AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
AFDIWX 900 PM EST WED JAN 3 2007
.UPDATE...
INCREASED CLOUD COVER INTO THE PARTLY CLOUDY RANGE OVERNIGHT DUE TO
AREA OF CIRRUS MOVG ACROSS THE AREA ATTM. THIS SHOULD CLEAR THE AREA
BEFORE DAYBREAK BUT STILL WILL BE SEVERAL HOURS OF SOMEWHAT OPAQUE
CLOUD COVER. HOURLY TEMPS ARE RUNNING A LITTLE COLDER THAN FCST AS
WINDS WERE LIGHTER OVER MUCH OF THE AREA THAN EXPECTED EARLY THIS
EVE. CLOUD COVER SHOULD LIMIT DIURNAL COOLING OVERNIGHT BUT STILL
APPEARS FORECAST MINS MAY BE A BIT TOO HIGH AND LOWERED SLIGHTLY,
BUT STILL ABOVE FREEZING.
&&
.AVIATION...
DRY AIRMASS CONTINUES OVER THE REGION THIS EVE. A WK SHRTWV WILL
MOVE THROUGH THE AREA OVERNIGHT RESULTING IN HIGH CLOUD CIGS. RECENT
TAMDAR SOUNDING FROM SBN INDICATES LOW LEVELS ARE DRY WITH MOISTURE
DECREASING FROM THE SFC UP TO ABOUT 3KFT, SO NO LOW CLOUDS EXPECTED
OVERNIGHT AND BRISK LOW LEVEL WINDS WILL PREVENT FOG FROM FORMING.
DEEPENING TROF OVER THE PLAINS OVER THE NEXT 24HRS WILL RESULT IN
LOW LEVEL MOISTURE STREAMING N-NE FM TX INTO THE MIDWEST TOMORROW.
THIS IS EXPECTED TO RESULT IN LOW VFR CIGS DVLPG THU WHICH WILL
LIKELY BE LWRG FURTHER THU NGT.
&&
.PREV DISCUSSION...
SHORT TERM...
TONIGHT THROUGH THURSDAY.
HIGH PRESSURE OVER THE AREA WAS DRIFTING EAST AS LOW PRESSURE AREAS
TO THE WEST MOVE EAST. BIGGEST FORECAST CONCERN IS CHANCES OF RAIN
ON THURSDAY AND SECONDARY CONCERNS WOULD BE CHANCES OF ANOTHER HEAVY
FROST OVERNIGHT AND WINDS.
CURRENTLY CLEAR AND VERY MILD...PER SATELLITE IMAGES AND SURFACE
REPORTS. STIFF SOUTHWEST WINDS WITH PERIODIC GUSTS TO AROUND 25 MPH
IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. GRADIENT IS FORECAST
TO REMAIN TIGHT THROUGH THURSDAY...SO 15 KNOT WINDS EXPECTED
THROUGH THE PERIOD.
ALL MODELS ARE SUGGESTING MEASURABLE RAINFALL WILL REMAIN SOUTH OF
THE AREA...OR JUST SKIM FURTHEST SOUTH AND EAST AREAS BY THURSDAY
AFTERNOON...EARLIEST. MOISTURE IS STRUGGLING TO MAKE IT THIS FAR
NORTH AS THE CENTER OF THE STORM SYSTEM IS FORECAST TO REMAIN WELL
SOUTH AND IS FORECAST TO OPEN/WEAKEN AS IT MOVES NORTHEAST.
AS FOR THE FROST...NORMALLY THIS TIME OF YEAR NOT A CONCERN...BUT
THE HEAVY FROST WE EXPERIENCED THIS MORNING CAUSED A LOT OF TRAFFIC
ACCIDENTS AND A FEW FATALITIES. CONSIDERED ISSUING AN SPS TO MENTION
THE POSSIBILITY BUT WITH WARMER (ABOVE FREEZING) TEMPS AND WINDS IN
EXCESS OF 10 KTS...NOT CONFIDENT THE FROST WILL REPEAT TONIGHT.
LATER SHIFT WILL HAVE TO MONITOR.
TEMPS NEXT FEW PERIODS WILL BE EVEN MILDER THAN LAST FEW PERIODS AS
WARM ADVECTION OVERSPREADS THE AREA. STRONG WINDS WILL KEEP THE
ATMOSPHERE MIXED...SO OVERNIGHT LOWS WILL ALSO BE MILDER THAN THE
LAST FEW NIGHTS.
IN SUMMARY...ADJUSTED TEMPS UP A FEW DEGREES MOST PERIODS AND BACKED
MENTION OF RAIN OFF UNTIL THURSDAY AFTERNOON.
LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY.
MORE PRESSING CONCERN REMAINS RAINFALL POTENTIAL AND AMOUNTS WITH
AREA OF LOW PRESSURE AND SERIES OF FRONTS AND WAVES SET TO AFFECT
THE AREA THROUGH SATURDAY. NORTHERN JET STREAM AND TROUGH TAKE SHAPE
IN RESPONSE TO THIS DIP IN THE FLOW STILL APPEARS ON TARGET TO
ARRIVE LATE FRIDAY INTO SATURDAY WHICH WILL ALLOW PESKY SOUTHERN
STREAM CUT OFF LOW OVER TX TO BE EJECTED AND EVENTUALLY OPEN AS BOTH
STREAMS ATTEMPT TO PHASE AND CARVE OUT A GENERAL TROUGH OVER MUCH OF
THE EASTERN US THROUGH MUCH OF THE PERIOD. 150+ KT JET STREAK
SCREAMING ACROSS THE PACIFIC AT THIS TIME POISED TO MOVE IN AS THE
SFC LOW APPROACHES. AS NOTED BY MID SHIFT...WATER VAPOR SHOWS THIS
CUTOFF LOW ALREADY BEGINNING TO PULL IN TROPICAL MSTR AND SEND IT
NORTH IN AN INCREASING SW FLOW. NO DOUBT MSTR WILL ARRIVE AS THIS
SYSTEM TAKES SHAPE BUT PLACEMENT DETAILS OF BEST MSTR FEED REMAINS
KEY IN TERMS OF RAINFALL AMOUNTS AND HYDROLOGIC CONCERNS. TRACK OF
THE SFC LOW REMAINS TRICKY WITH NAM-WRF AND EARLIER RUNS OF GFS
TAKING THE LOW TO THE NEW OF THE CWA. EURO AND NOW THE 12Z GFS TRACK
THE SFC LOW OVER OR JUST SE OF THE CWA. ENOUGH CONSISTENCY HAS BEEN
IN PLACE TO ALLOW THE MID SHIFT TO INCREASE POPS TO LIKELY IN SE
AREAS THURS NGT/FRIDAY WHERE AT THIS POINT HEAVIEST RAINFALL WOULD
SEEM MOST LIKELY. SEVERAL SCENARIOS CONTINUE TO BE POSSIBLE RANGING
FROM MAJORITY OF PRECIP REMAINING SE AND NW AREAS SEEING LITTLE OR
NOTHING TO ENTIRE CWA GETTING ONE OR 2 ROUNDS OF SOAKING RAINS TO
EVEN SOME THUNDER POTENTIAL IF HIGHER DEWPTS AND FURTHER NW TRACK
OCCURS AS SHOWN BY NAM-WRF. JUST TOO MANY VARIABLES THAT REMAIN
UNSOLVED AND TO CHANGE ANYTHING AT THIS POINT WOULD BE PREMATURE AND
POTENTIALLY CAUSE A FLIP-FLOP IN THE FORECAST. WILL MAINTAIN GRIDS
THURS NGT THROUGH FRI NGT. COLD FRONT SHOULD HAVE CLEARED THE AREA
BY LATE SATURDAY WITH A RETURN TO COOLER...BUT STILL ABOVE NORMAL
TEMPS IN THE MID TO UPPER 30S. WILL MAINTAIN POPS ON SATURDAY FOR
NOW WITH FROPA AND RESIDUAL MSTR. HIGH PRESSURE WILL ATTEMPT TO
BUILD IN FROM THE SOUTH...BUT SEVERAL WAVES WILL MOVE THROUGH THE NW
FLOW IN THE FORM OF CLIPPER TYPE SYSTEMS. WITH GULF CUT OFF AND MSTR
APPEARING LIMITED WITH EACH OF THESE SYSTEMS AS WELL AS TIMING
RESOLUTION BEING POOR ON FEATURES THAT FAR OUT...THINK DRY FORECAST
CAN BE SAFELY MAINTAINED SUNDAY THROUGH WEDS. AS ELUDED TO BY MID
SHIFT...SOME LAKE EFFECT POTENTIAL MAY EXIST IN WAKE OF EACH OF
THESE WAVES AS SLIGHTLY COLDER AIR ARRIVES WITH EACH ONE AND LAKE
TEMPS STILL AROUND 40 F TO PROVIDE LOTS OF ENERGY. OUTSIDE THE
FORECAST PERIOD...LARGE POLAR HIGH AND CORE OF MUCH COLDER AIR
APPEARS TO BE DEPICTED BY MODELS TO VARYING DEGREES TO BEGIN A SLOW
SE TREND ACROSS WESTERN CANADA WHICH COULD SPELL OUT ARRIVAL OF MORE
WINTER LIKE CONDITIONS...BUT LOTS OF TIME BETWEEN NOW AND THEN TO
MONITOR.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT UNTIL 7 PM EST THURSDAY
FOR LMZ043-LMZ046.
&&
$$
SHORT TERM...EDDY
LONG TERM...FISHER
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
AFDIWX 635 PM EST WED JAN 3 2007
.AVIATION...
DRY AIRMASS CONTINUES OVER THE REGION THIS EVE. A WK SHRTWV WILL
MOVE THROUGH THE AREA OVERNIGHT RESULTING IN HIGH CLOUD CIGS. RECENT
TAMDAR SOUNDING FROM SBN INDICATES LOW LEVELS ARE DRY WITH MOISTURE
DECREASING FROM THE SFC UP TO ABOUT 3KFT, SO NO LOW CLOUDS EXPECTED
OVERNIGHT AND BRISK LOW LEVEL WINDS WILL PREVENT FOG FROM FORMING.
DEEPENING TROF OVER THE PLAINS OVER THE NEXT 24HRS WILL RESULT IN
LOW LEVEL MOISTURE STREAMING N-NE FM TX INTO THE MIDWEST TOMORROW.
THIS IS EXPECTED TO RESULT IN LOW VFR CIGS DVLPG THU WHICH WILL
LIKELY BE LWRG FURTHER THU NGT.
&&
.PREV DISCUSSION...
SHORT TERM...
TONIGHT THROUGH THURSDAY.
HIGH PRESSURE OVER THE AREA WAS DRIFTING EAST AS LOW PRESSURE AREAS
TO THE WEST MOVE EAST. BIGGEST FORECAST CONCERN IS CHANCES OF RAIN
ON THURSDAY AND SECONDARY CONCERNS WOULD BE CHANCES OF ANOTHER HEAVY
FROST OVERNIGHT AND WINDS.
CURRENTLY CLEAR AND VERY MILD...PER SATELLITE IMAGES AND SURFACE
REPORTS. STIFF SOUTHWEST WINDS WITH PERIODIC GUSTS TO AROUND 25 MPH
IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. GRADIENT IS FORECAST
TO REMAIN TIGHT THROUGH THURSDAY...SO 15 KNOT WINDS EXPECTED
THROUGH THE PERIOD.
ALL MODELS ARE SUGGESTING MEASURABLE RAINFALL WILL REMAIN SOUTH OF
THE AREA...OR JUST SKIM FURTHEST SOUTH AND EAST AREAS BY THURSDAY
AFTERNOON...EARLIEST. MOISTURE IS STRUGGLING TO MAKE IT THIS FAR
NORTH AS THE CENTER OF THE STORM SYSTEM IS FORECAST TO REMAIN WELL
SOUTH AND IS FORECAST TO OPEN/WEAKEN AS IT MOVES NORTHEAST.
AS FOR THE FROST...NORMALLY THIS TIME OF YEAR NOT A CONCERN...BUT
THE HEAVY FROST WE EXPERIENCED THIS MORNING CAUSED A LOT OF TRAFFIC
ACCIDENTS AND A FEW FATALITIES. CONSIDERED ISSUING AN SPS TO MENTION
THE POSSIBILITY BUT WITH WARMER (ABOVE FREEZING) TEMPS AND WINDS IN
EXCESS OF 10 KTS...NOT CONFIDENT THE FROST WILL REPEAT TONIGHT.
LATER SHIFT WILL HAVE TO MONITOR.
TEMPS NEXT FEW PERIODS WILL BE EVEN MILDER THAN LAST FEW PERIODS AS
WARM ADVECTION OVERSPREADS THE AREA. STRONG WINDS WILL KEEP THE
ATMOSPHERE MIXED...SO OVERNIGHT LOWS WILL ALSO BE MILDER THAN THE
LAST FEW NIGHTS.
IN SUMMARY...ADJUSTED TEMPS UP A FEW DEGREES MOST PERIODS AND BACKED
MENTION OF RAIN OFF UNTIL THURSDAY AFTERNOON.
LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY.
MORE PRESSING CONCERN REMAINS RAINFALL POTENTIAL AND AMOUNTS WITH
AREA OF LOW PRESSURE AND SERIES OF FRONTS AND WAVES SET TO AFFECT
THE AREA THROUGH SATURDAY. NORTHERN JET STREAM AND TROUGH TAKE SHAPE
IN RESPONSE TO THIS DIP IN THE FLOW STILL APPEARS ON TARGET TO
ARRIVE LATE FRIDAY INTO SATURDAY WHICH WILL ALLOW PESKY SOUTHERN
STREAM CUT OFF LOW OVER TX TO BE EJECTED AND EVENTUALLY OPEN AS BOTH
STREAMS ATTEMPT TO PHASE AND CARVE OUT A GENERAL TROUGH OVER MUCH OF
THE EASTERN US THROUGH MUCH OF THE PERIOD. 150+ KT JET STREAK
SCREAMING ACROSS THE PACIFIC AT THIS TIME POISED TO MOVE IN AS THE
SFC LOW APPROACHES. AS NOTED BY MID SHIFT...WATER VAPOR SHOWS THIS
CUTOFF LOW ALREADY BEGINNING TO PULL IN TROPICAL MSTR AND SEND IT
NORTH IN AN INCREASING SW FLOW. NO DOUBT MSTR WILL ARRIVE AS THIS
SYSTEM TAKES SHAPE BUT PLACEMENT DETAILS OF BEST MSTR FEED REMAINS
KEY IN TERMS OF RAINFALL AMOUNTS AND HYDROLOGIC CONCERNS. TRACK OF
THE SFC LOW REMAINS TRICKY WITH NAM-WRF AND EARLIER RUNS OF GFS
TAKING THE LOW TO THE NEW OF THE CWA. EURO AND NOW THE 12Z GFS TRACK
THE SFC LOW OVER OR JUST SE OF THE CWA. ENOUGH CONSISTENCY HAS BEEN
IN PLACE TO ALLOW THE MID SHIFT TO INCREASE POPS TO LIKELY IN SE
AREAS THURS NGT/FRIDAY WHERE AT THIS POINT HEAVIEST RAINFALL WOULD
SEEM MOST LIKELY. SEVERAL SCENARIOS CONTINUE TO BE POSSIBLE RANGING
FROM MAJORITY OF PRECIP REMAINING SE AND NW AREAS SEEING LITTLE OR
NOTHING TO ENTIRE CWA GETTING ONE OR 2 ROUNDS OF SOAKING RAINS TO
EVEN SOME THUNDER POTENTIAL IF HIGHER DEWPTS AND FURTHER NW TRACK
OCCURS AS SHOWN BY NAM-WRF. JUST TOO MANY VARIABLES THAT REMAIN
UNSOLVED AND TO CHANGE ANYTHING AT THIS POINT WOULD BE PREMATURE AND
POTENTIALLY CAUSE A FLIP-FLOP IN THE FORECAST. WILL MAINTAIN GRIDS
THURS NGT THROUGH FRI NGT. COLD FRONT SHOULD HAVE CLEARED THE AREA
BY LATE SATURDAY WITH A RETURN TO COOLER...BUT STILL ABOVE NORMAL
TEMPS IN THE MID TO UPPER 30S. WILL MAINTAIN POPS ON SATURDAY FOR
NOW WITH FROPA AND RESIDUAL MSTR. HIGH PRESSURE WILL ATTEMPT TO
BUILD IN FROM THE SOUTH...BUT SEVERAL WAVES WILL MOVE THROUGH THE NW
FLOW IN THE FORM OF CLIPPER TYPE SYSTEMS. WITH GULF CUT OFF AND MSTR
APPEARING LIMITED WITH EACH OF THESE SYSTEMS AS WELL AS TIMING
RESOLUTION BEING POOR ON FEATURES THAT FAR OUT...THINK DRY FORECAST
CAN BE SAFELY MAINTAINED SUNDAY THROUGH WEDS. AS ELUDED TO BY MID
SHIFT...SOME LAKE EFFECT POTENTIAL MAY EXIST IN WAKE OF EACH OF
THESE WAVES AS SLIGHTLY COLDER AIR ARRIVES WITH EACH ONE AND LAKE
TEMPS STILL AROUND 40 F TO PROVIDE LOTS OF ENERGY. OUTSIDE THE
FORECAST PERIOD...LARGE POLAR HIGH AND CORE OF MUCH COLDER AIR
APPEARS TO BE DEPICTED BY MODELS TO VARYING DEGREES TO BEGIN A SLOW
SE TREND ACROSS WESTERN CANADA WHICH COULD SPELL OUT ARRIVAL OF MORE
WINTER LIKE CONDITIONS...BUT LOTS OF TIME BETWEEN NOW AND THEN TO
MONITOR.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT UNTIL 7 PM EST THURSDAY
FOR LMZ043-LMZ046.
&&
$$
SHORT TERM...EDDY
LONG TERM...FISHER
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 958 PM EST WED JAN 3 2007
.SHORT TERM /REST OF TONIGHT/...
HIGH PRESSURE OVER THE MID ATLANTIC WILL CONTINUE TO DRIFT EAST
OVERNIGHT. ONLY A FEW CHANGES MADE TO THE OVERNIGHT
FORECAST...MAINLY BASED ON CURRENT TRENDS. CLOUD COVER WILL INCREASE
FROM THE SOUTH OVERNIGHT...SO HAVE ADJUSTED GRID TIMING ACCORDINGLY.
ALSO...WITH THOSE ADJUSTMENTS COME TEMPERATURE ADJUSTMENTS. HAVE
LOWERED TEMPERATURES IN THE WEST AND INCREASED THEM IN THE SOUTH BY
A COUPLE DEGREES. UPDATES WILL BE OUT SHORTLY.
&&
.AVIATION /03Z-24Z/...
HIGH CLOUDS WILL SPREAD FROM THE SOUTHWEST OVERNIGHT AHEAD OF A LOW
PRESSURE SYSTEM OVER THE CENTRAL GULF COAST. GIVEN INCREASING DEW
POINTS AND WARMER OVERNIGHT LOW TEMPERATURES...THERE IS A
POSSIBILITY OF FOG. CONFIDENCE IS LOW FOR STRATUS TONIGHT...SO HAVE
ONLY INCLUDED FOG IN THE TAFS. SOUTHERLY WINDS WILL SOUTHERLY WINDS
WILL GRADUALLY INCREASE TOMORROW AFTERNOON.
&&
.PREV DISCUSSION...
/ISSUED 243 PM EST WED JAN 3 2007/
SHORT TERM /TONIGHT THROUGH THURSDAY/...
WATER VAPOR LOOP SHOWS A NORTHERN STREAM WAVE PASSING OVER THE
NORTHERN MID ATLANTIC...FOLLOWED BY A WAVE MOVING EAST INTO THE
EASTERN GREAT LAKES. A CUTOFF UPPER LOW IS SPINNING OVER NORTHERN
MEXICO. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 60-90KT WESTERLY
JET FROM THE OHIO VALLEY EAST THROUGH THE NORTHERN MID ATLANTIC. 12Z
SURFACE ANALYSIS PLACED A 1033MB ANTICYCLONE SPRAWLED ACROSS THE
EAST COAST AND GULF STATES. A FRONTAL BOUNDARY HAS BECOME STATIONARY
ACROSS THE CENTRAL GULF OF MEXICO...SOUTHERN FLORIDA AND OFF THE
SOUTH CAROLINA COAST.
THE SKY WILL BEGIN CLEAR THIS EVENING...WITH HIGH LEVEL MOISTURE
TRANSPORTING NORTHEAST INTO THE REGION AS THE UPPER LEVEL RIDGE AXIS
PASSES OVERHEAD. AM SOMEWHAT CONCERNED ABOUT A MARINE AIRMASS
CONSISTING OF LOW LEVEL STRATO-CU LOCATED ACROSS THE EASTERN
CAROLINAS MAY ADVECT CLOSER TO THE REGION AS THE SURFACE HIGH MOVES
OFF THE EAST COAST. WITH SOUTHWESTERLY BOUNDARY LAYER FLOW...BEST
GUESS IS THAT THIS AIRMASS ONLY REACHES INTO SOUTHEAST VIRGINIA.
LATER SHIFTS WILL HAVE TO MONITOR ITS PROGRESS.
ANOTHER GOOD DECOUPLING OPPORTUNITY TONIGHT WILL ALLOW TEMPERATURES
TO FALL NEAR 30F (CONSIDERING WARM ADVECTION DURING THE PAST 24
HOURS). THERE COULD BE SOME LIGHT PATCHY FOG AS DEW POINTS ARE
FORECAST TO JUMP DURING MORNING MIXING. TEMPERATURES ACROSS THE
HIGHER TERRAIN ABOVE 2500 FEET WILL BE MUCH WARMER AS WINDS REMAIN
SUSTAINED OVERNIGHT (IN THE LOWER 40S).
UPPER LEVEL MOISTURE CONTINUES TO OVERSPREAD THE MID ATLANTIC
THURSDAY...BUILDING DOWN INTO THE MID LEVELS. AT THIS POINT AM GOING
WITH SOME PARTIAL SUNSHINE...ESPECIALLY ACROSS CENTRAL MARYLAND.
WITH ONLY SLIGHT WARM ADVECTION...TEMPERATURES ARE EXPECTED TO EASE
TOWARD 60F THURSDAY WITH CONTINUED SOUTHWEST FLOW.
AVIATION /20Z-18Z/...
WINDS SLACKEN DIURNALLY WITH SUNSET. THERE COULD BE SOME LIGHT
PATCHY FOG TOMORROW MORNING...SIMILAR TO AT KMRB THIS
MORNING...UNDER DECENT RADIATIONAL COOLING CONDITIONS. UPPER LEVEL
MOISTURE WILL BE INCREASING FROM THE SOUTHWEST LATE TONIGHT THROUGH
TOMORROW.
HAVE NOTICED MARINE STRATO-CU ACROSS THE CAROLINAS. BELIEVE
SOUTHWEST BOUNDARY LAYER FLOW WILL PREVENT THIS AIRMASS FROM
REACHING THE TERMINALS...BUT ITS SOMETHING TO WATCH OVERNIGHT.
MARINE...
12Z GFS/ETA MOS AT THOMAS POINT BOTH SUGGEST SUSTAINED WINDS WILL
INCREASE INTO THE 10 TO 15KT RANGE TOMORROW FROM 10KT OVERNIGHT. 12Z
NAM/GFS PROXIMITY LAND BUFKIT FORECAST SOUNDINGS SUGGEST ADDITIONAL
WIND GUST MOMENTUM MAY BRIEFLY REACH 18KT TOMORROW AFTERNOON. WILL
KEEP WINDS BELOW SMALL CRAFT CRITERIA...IN THE 10 TO 15KT RANGE
GIVEN SOUTHWEST WARM FLOW OVER MID 40 DEGREE WATER.
TIDES...
WATER LEVELS ARE CURRENTLY A HALF FOOT ABOVE ASTRONOMIC PREDICTIONS.
THE LUNAR CYCLE IS AT A FULL MOON (100% FULL). THE CHESAPEAKE AND
POTOMAC ARE RECOVERING FROM A BLOWOUT. BOTH THE CHESAPEAKE BAY
OPERATIONAL FORECAST SYSTEM AND NOAA EXTRATROPICAL STORM SURGE MODEL
GUIDANCE MAINTAIN CURRENT WATER LEVEL DEPARTURES THROUGH THE SHORT
TERM.
LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
BY THURSDAY NIGHT THE HIGH IS WELL OFF THE COAST AND RETURN FLOW IS
STREAMING MOISTURE AND RAIN UP THE WEST SIDE OF THE APPS AND ALSO UP
FROM THE SE STATES. CHCS FOR RAIN IMPROVE THROUGH THE NIGHT AND BY
FRI MORNING RAIN IS CATEGORICAL POPS IN THE MOUNTAINS...LIKELY WEST
OF THE BLUE RIDGE... AND HIGH CHC TO THE EAST.
LOW PRES WILL LIFT NORTH THRU THE MIDWEST FRIDAY AND FRI NIGHT
MOVING A WARM FRONT TO OUR N BY SAT MORNING. RAIN IS LIKELY OR
CATEGORICAL POPS FRIDAY... THEN JUST CHC FRI NIGHT AS THE FRONT
LIFTS NORTH. NOT EXPECTING A DELUGE... BUT A DECENT RAIN WITH THE
EVENT. EXPECTING BETWEEN A QUARTER AND THREE QUARTERS OF AN INCH OF
RAIN BETWEEN THU NIGHT AND FRI NIGHT.
ALTHOUGH CONFIDENCE IS NOT EXCEPTIONALLY HIGH...SAT LOOKS TO BE A
RATHER NICE DAY AT THE MOMENT. THE LOW LIFTS THE WARM FRONT INTO PA
AND NORTHERN NJ...AND THE COLD FRONT STILL LAGS BACK OVER THE
MISSISSIPPI RIVER. THAT SHOULD PUT US FIRMLY IN THE WARM SECTOR
ASSUMING THE WARM FRONT TAKES THE HINT AND DOES INDEED PUSH UP TO
OUR NORTH... ALWAYS A TROUBLE SPOT DURING THE COOL SEASON.
COLD FRONT PUSHES THRU LATE SAT NIGHT OR SUN MORN FOLLOWED BY MILD
HIGH PRESSURE AGAIN. LATE SUN NIGHT OR MONDAY MORN A MORE
SUBSTANTIAL COLD FRONT MOVES THROUGH WITH MORE SEASONABLE DAYTIME
TEMPS IN THE 40S AND A CHC FOR SOME MINOR UPSLOPE SNOW SHOWERS IN
THE MTNS FOR THE EARLY WEEK.
WINTER STILL NOWHERE TO BE FOUND IN THE EAST. THERE STILL IS A
MASSING OF COLD AIR IN CANADA AND THE NORTHERN STATES FORECAST BY
MID MONTH... BUT NOT AS COLD AS IT WAS FORECAST BY YESTERDAYS GFS
RUN. IT CERTAINLY WOULD APPEAR THAT THE SECOND HALF OF JAN IS OUR
CHANCE FOR REAL WINTER. WASHINGTON IS UP TO SIXTH AND BALTIMORE
NINTH WARMEST PERIOD SINCE NOV 23RD THANKSGIVING...AND CLIMBING AS
LONG AS WE KEEP UP THE LACK OF COLD AIR.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SHORT TERM/AVIATION...SAR
PREV. DISCUSSION...ROGOWSKI/STRONG
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 238 PM EST TUE JAN 2 2007
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
WATER VAPOR LOOP SHOWS A WAVE MOVING OFF THE NEW ENGLAND SHORE. THE
NEXT NORTHERN STREAM WAVE IS TILTED POSITIVELY AS IT MOVES ACROSS
THE UPPER MIDWEST. A DEEP UPPER LOW IS SINKING SOUTH INTO NORTHERN
MEXICO. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-120KT
WESTERLY JET FROM THE MIDWEST EAST ACROSS THE NORTHERN MID ATLANTIC.
12Z SURFACE ANALYSIS PLACED A SECONDARY COLD FRONT FROM THE NEW
ENGLAND SHORE SOUTHWEST THROUGH WESTERN MARYLAND. A TROUGH WAS IN
THE LEE OF THE APPALACHIANS...WITH A 1032MB ANTICYCLONE SPRAWLED
ACROSS THE CENTRAL CONUS.
THE SKY WILL START OUT CLEAR THIS EVENING WITH THE EROSION OF
MOUNTAIN STRATO-CU. HAVE RAISED CLOUD COVER (ESPECIALLY
ACROSS THE NORTHERN FORECAST AREA) LATE TONIGHT AND WEDNESDAY
MORNING IN ANTICIPATION OF INCREASING HIGH LEVEL MOISTURE
ASSOCIATED WITH THE PASSAGE OF THE NORTHERN STREAM WAVE FROM THE
LOWER GREAT LAKES REGION. THE SKY SHOULD CLEAR FOR THE AFTERNOON
HOURS BEHIND THE WAVE...AS A NORTHWESTERLY UPPER LEVEL JET
STRENGTHENS ACROSS THE TENNESSEE VALLEY...TRAPPING UPPER LEVEL
MOISTURE FROM THE SOUTHERN STREAM SYSTEM SOUTH OF THE REGION.
LOWS TONIGHT WILL RANGE FROM THE MID TO UPPER 30S DOWNTOWN...LOW 30S
ABOVE 2500FT AND ALONG THE BAY...TO THE MID 20S ACROSS RURAL LOW
LYING AREAS. THE ADVECTION SIGN WILL SHIFT FROM COLD TO WARM
OVERNIGHT...WITH SOUTHWEST WINDS USHERING IN +5C OF WARMING NEAR
850MB. 09Z SHORT RANGE ENSEMBLES SUGGEST 850MB TEMPERATURES TOMORROW
WILL BE +1-1.5 STANDARD DEVIATIONS ABOVE CLIMATOLOGY. THIS WILL
SUPPORT HIGH TEMPERATURES REACHING 60F WEDNESDAY.
&&
.AVIATION /20Z-18Z/...
P6SM SKC THROUGH MUCH OF THE NIGHT. WINDS GUSTS HAVE SLACKENED WITH
A SURFACE HIGH BUILDING IN. MAY SEE FEW-SCT250 AS UPPER LEVEL
MOISTURE ADVECTS IN AHEAD OF A WEAK SHORTWAVE LATE TONIGHT AND
TOMORROW MORNING.
&&
.MARINE...
12Z GFS/ETA MOS AT THOMAS POINT...15Z LWX WRF-NMM MARINE AND 12Z
NAM/GFS PROXIMITY LAND BUFKIT FORECAST SOUNDINGS ALL SUGGEST
SUSTAINED WINDS AND GUSTS WILL QUICKLY FALL BELOW SMALL CRAFT
CRITERIA THROUGH THE MID AFTERNOON. 18Z OBSERVATIONS ALREADY SHOW
THIS TREND...SO WILL CANCEL THE SMALL CRAFT ADVISORY WITH THE 330PM
COASTAL WATER FORECAST ISSUANCE.
WINDS WILL APPROACH SMALL CRAFT FRIDAY AFTERNOON AND EVENING BUT AT
THIS TIME ARE FORECAST TO STAY JUST BELOW 15 KT.
&&
.TIDES...
WATER LEVELS ARE CURRENTLY AT OR JUST BELOW ASTRONOMIC PREDICTIONS.
THE LUNAR CYCLE IS AT A FULL MOON (99% FULL). THE CHESAPEAKE AND
POTOMAC EXPERIENCED A BLOWOUT...WITH WATER LEVELS RETURNING NEAR
NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
IT WILL TAKE SOME TIME FOR THE LARGE HIGH TO MOVE ACROSS THE AREA...
BUT BY THU NIGHT RETURN FLOW WILL BRING RAIN BACK INTO THE FORECAST.
ONCE IT IS HERE THAT UNSETTLED WEATHER WILL LAST UNTIL SATURDAY WHEN
A COLD FRONT WILL FINALLY CLEAR THE REGION WITH A RETURN TO TEMPS
THAT ARE CLOSER TO SEASONABLE BUT CERTAINLY NOT COLD FOR EARLY NEXT
WEEK. BEST CHANCE OF RAIN SEEMS TO BE LATE THU NIGHT INTO FRI MORN
AT THE MOMENT... AND THE TIMING SEEMS TO BE SETTLING IN AFTER SOME
ACCELERATION IN THE SYSTEM DURING PREVIOUS MODEL RUNS.
IN THE VERY LONG TERM. WINTER DOES SEEM TO BE MASSING ITS TROOPS ON
THE CANADIAN BORDER DURING MIDDLE JANUARY. THE PAST FEW RUNS ON THE
GFS INDICATE A PATTERN SHIFT UPCOMING LATER IN THE MONTH AS THE
POLAR VORTEX SWINGS AROUND TO OUR PART OF THE GLOBE. IT CERTAINLY
WOULD MAKE SENSE AS WE NOW HAVE HAD SEVERAL WEEKS OF ABNORMALLY WARM
TEMPERATURES AND IT IS DIFFICULT TO MAINTAIN A LARGE ANOMALY LIKE
THAT FOR MORE THAN A FEW WEEKS. OTHER THAN A FEW BRIEF SHOTS OF COOL
AIR... WE HAVE BEEN NEAR TO WELL ABOVE NORMAL SINCE EARLY NOVEMBER.
DECEMBER WAS THE TENTH WARMEST ON RECORD IN DC AND 13TH WARMEST FOR
BALTIMORE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SHORT TERM...ROGOWSKI
LONG TERM...STRONG
AVIATION...ROGOWSKI
MARINE...ROGOWSKI/STRONG
TIDES...ROGOWSKI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 940 AM EST TUE JAN 2 2006
.SHORT TERM...
WATER VAPOR LOOP SHOWS A WAVE MOVING OFF THE NEW ENGLAND SHORE. THE
NEXT NORTHERN STREAM WAVE IS TILTED POSITIVELY AS IT MOVES ACROSS
THE UPPER MIDWEST. A DEEP UPPER LOW IS SINKING SOUTH INTO NORTHERN
MEXICO. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-120KT
WESTERLY JET FROM THE MIDWEST EAST ACROSS THE NORTHERN MID ATLANTIC.
12Z SURFACE ANALYSIS PLACED A SECONDARY COLD FRONT FROM THE NEW
ENGLAND SHORE SOUTHWEST THROUGH WESTERN MARYLAND. A TROUGH WAS IN
THE LEE OF THE APPALACHIANS...WITH A 1032MB ANTICYCLONE SPRAWLED
ACROSS THE CENTRAL CONUS.
SECONDARY COLD FRONT PASSAGE WILL PROMOTE CONTINUED BREEZY WINDS
THROUGH THE EARLY AFTERNOON. WINDS ATOP THE MIX LAYER ARE NEAR 40KT
SAMPLED BY MORNING ACARS SOUNDINGS AND THE 12Z KIAD RAOB...WHICH
COULD GET WIND GUSTS ABOVE 30 MPH DURING A SHORT OVERLAPPING PERIOD
OF DEEPER MIXING LATE THIS MORNING...BEFORE THE WIND CORE ALOFT
MOVES EAST OF THE FORECAST AREA.
COMBINATION OF DRY ADVECTION AND STRONG DOWNSLOPE WILL CONTINUE TO
ERODE UPSLOPE CLOUDS ALONG THE MOUNTAINS. MIXING UP TO THE
SUBSIDENCE INVERSION BETWEEN 850MB AND 900MB SHOULD ALLOW
TEMPERATURES TO BREAK 50F.
&&
.AVIATION...
P6SM SKC WITH WIND GUSTS AROUND 25 KNOTS DIMINISHING DURING THE
AFTERNOON.
&&
.MARINE...
06Z GFS AND 00Z ETA MOS AT THOMAS POINT SUGGEST SUSTAINED WINDS IN
THE 15 TO 20 KT RANGE WILL GRADUALLY DIMINISH DURING THE MID
AFTERNOON. 09Z LWX WRF-NMM MARINE AND 06Z NAM/GFS PROXIMITY LAND
BUFKIT FORECAST SOUNDINGS ALL SUGGEST THE SAME TREND WITH ANY WIND
GUSTS ABOVE THE SUSTAINED 15 TO 20 KT RANGE DIMINISHING DURING THE
MID MORNING. HAVE LEFT THE 22Z END TIME FOR THE SMALL CRAFT ADVISORY
SO NOT TO CUT IT SO CLOSE...BUT ANTICIPATE CANCELING IT WITH THE
AFTERNOON PACKAGE BETWEEN 3 AND 4 PM.
&&
.TIDES...
WATER LEVELS ARE CURRENTLY AT OR JUST BELOW ASTRONOMIC PREDICTIONS.
THE LUNAR CYCLE IS AT A FULL MOON (99% FULL). THE CHESAPEAKE AND
POTOMAC EXPERIENCED A BLOWOUT...WITH WATER LEVELS RETURNING NEAR
NORMAL.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR ANZ530>537.
&&
$$
SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
AFDMQT 951 PM EST WED JAN 3 2007
.UPDATE...
MAIN FCST ISSUE OVERNIGHT IS POTENTIAL OF LIGHT PCPN.
WATER VAPOR IMAGERY SHOWS A WELL-DEFINED SHORTWAVE TRACKING ACROSS
CNTRL MANITOBA. 110KT UPPER JET SUPPORTING SHORTWAVE PER 00Z CWPL
SOUNDING IS PLACING RIGHT ENTRANCE REGION UPPER DIVERGENCE OVER THE
UPPER MISSISSIPPI VALLEY. RESULT HAS BEEN AN EXPANSION AND LOWERING
OF INITIALLY HIGH BASED MID CLOUDS IN THE WAA/ISENTROPIC ASCENT
PATTERN OVER THE LAST FEW HRS ACROSS ERN MN/NW WI AND WRN UPPER MI.
KMQT RADAR HAS SHOWN REFLECTIVITIES OCCASIONALLY AS HIGH AS 25-30DBZ
(UP TO 40DBZ IN MOST RECENT SCAN) IN THE BAND OF MID CLOUDS OVER WRN
UPPER MI. EVEN THOUGH AWOS/ASOS SITES HAVE SHOWN CLOUDS NO LWR THAN
8.5KFT...40DBZ AT 5.3KFT AGL IS LIKELY SUFFICIENT FOR SPRINKLES TO
BE REACHING THE SFC. EVENING TAMDAR SOUNDINGS FROM KSAW AND KCMX
SHOWED A FAIR AMOUNT OF DRY AIR TO OVERCOME...MORE SO WITH REGARD TO
DEPTH RATHER THAN BEING EXTREMELY DRY (DRY LAYER HAD RH GENERALLY
40-50PCT). UPSTREAM...00Z KINL SOUNDING HAS BECOME ESSENTIALLY
SATURATED THRU THE COLUMN SINCE THE 12Z SOUNDING.
GIVEN EVENING TRENDS AND POTENTIAL FOR FURTHER MOISTENING AS
INDICATED BY 00Z KINL SOUNDING...WILL MENTION SPRINKLES/ISOLD -SHRA
OVER ROUGHLY THE NW HALF OF FCST AREA OVERNIGHT WHERE SUFFICIENT
COLUMN MOISTENING IS LIKELY TO OCCUR. 00Z KGRB SOUNDING STILL
DEPICTED A VERY DRY COLUMN...SO WOULD EXPECT THE SCNTRL AND E TO
REMAIN DRY.
WINDS HAVE BEEN GUSTING FAIRLY HIGH OVER THE ERN FCST AREA (30-35MPH
AT KERY AND 30-40MPH AT GRAND MARAIS) UNDER FAVORABLE 190-210 WIND
DIRECTION FOR THAT PORTION OF UPPER MI. THIS SHOULD CONTINUE FOR THE
NEXT SEVERAL HRS AS LOW-LEVEL JET TRANSLATES ACROSS THE AREA.
WILL BUMP MIN TEMPS UP A DEGREE OR TWO BASED ON THICKENING CLOUD
COVER. MOST AREAS WILL LIKELY STAY ABOVE FREEZING OVERNIGHT.
&&
.PREV DISCUSSION... ISSUED AT 425 PM EST
SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
WV IMAGERY AND RUC ANALYSIS INDICATED MAINLY ZONAL MID/UPPER LEVEL
FLOW OVER SRN CANADA AND NRN CONUS WHILE A SRN STREAM CUTOFF LOW
CIRCULATES OVER NW MEXICO. AN UPSTREAM SHORTWAVE WAS NOTED MOVING
THROUGH CENTRAL SASKATCHEWAN AND MANITOBA WHILE ANOTHER SHORTWAVE
WAS BEING DRIVEN ONSHORE OVER THE PAC NW BY 160 3H JET STREAM. AT
THE SFC...A SSW FLOW PREVAILED OVER THE FORECAST AREA BTWN A RDG
OVER THE ATLANTIC COAST AND E AND SRN CONUS AND LOW PRES OVER CNTRL
CANADA.
TONIGHT...LOOK FOR INCREASING MID CLOUDS WITH UPR DIV IN RRQ OF JET
MAX MOVING THROUGH CENTRAL CANADA AND INCREASING WAA. THIS SHOULD
KEEP TEMPS FROM DROPPING OFF TOO MUCH ESPECIALLY FOR AREAS ALONG
LAKE SUPERIOR WITH DOWNSLOPING SRLY FLOW. KEPT READINGS CLOSE TO
GOING FCST AND IN GENERALLY IN LINE WITH GFS/NAM GUIDANCE VALUES.
THU INTO THU NIGHT...12Z MODEL CONSENSUS INDICATES WEAK UPR DIV AND
MID-LVL Q-VECT CONV OVER THE FAR WRN FCST AREA AS PACIFIC SHORTWAVE
EMERGES OUT OF THE PLAINS. GFS ALSO INDICATE 800-500 MB FGEN
SUPPORT. HOWEVER...GIVEN HOW DRY 12Z UPSTREAM SNDGS ARE OVER THE
PLAINS STATES...PCPN CHCS STILL SEEM VERY MUCH IN QUESTION. UKMET
AND NAM GENERALLY KEEP ENTIRE CWA DRY THROUGH 12Z FRI WITH ONLY SOME
PCPN REACHING INTO WRN AND CENTRAL LAKE SUPERIOR. CANADIAN MODEL
ALSO LOOKS DRY EXCEPT FOR SOME PCPN REACHING INTO FAR WRN COUNTIES
THU AFTERNOON. GFS ON THE OTHER HAND IS THE OUTLIER...BRINGING LIGHT
PCPN IN ACROSS CWA THU AND THU AFTERNOON. GIVEN DRY AIRMASS IN
PLACE...I`M MORE INCLINED TO BELIEVE DRIER SOLUTION IS BEST BUT
SINCE THERE IS STILL SOME MODEL UNCERTAINTY WILL KEEP A SLIGHT CHC
OF PCPN IN FOR THE FAR WRN COUNTIES ON THU WITH A LOW CHC POP FOR
THU EVENING AS PACIFIC SHORTWAVE AND ASSOC SFC TROF PASS THROUGH THE
AREA. WILL KEEP CENTRAL COUNTIES DRY ON THU BUT BRING A SLIGHT CHC
IN FOR THU EVENING. WITH A POSSIBILITY FOR SOME EVAPORATIVE AND
DYNAMIC COOLING...MODEL FCST SNDGS INDICATE EITHER RAIN OR SNOW AS
PTYPE. ANY LIGHT PCPN THAT DOES FORM SHOULD END BY LATE THU NIGHT AS
SHORTWAVE LIFTS NE OF LAKE SUPERIOR.
LONG TERM (12Z FRIDAY THROUGH DAY 7)...
DECIDED TO DELAY PRECIPITAITON ON FRIDAY TIL 21Z AS BETTER DYNAMICS
NOTED IN 850-700MB FRONTOGENESIS ARE DELAYED TILL ABOUT THAT TIME.
FROM THERE ON LES POTENTIAL LOOKS MARGINAL THROUGH 18Z WITH 850
TEMPS AROUND -9 OR -10 CELSIUS...BUT I CAN`T RULE IT OUT. SO DECIDED
TO LEAVE WX GRIDS AS IS FOR THAT TIME. MODELS HAVE DECENT AGREEMENT
WITH NEXT SYSTEM PASSING THROUGH THE FA LATE SUNDAY NIGHT/MONDAY
MORNING. AS FOR RUN TO RUN CONTINUITY...THE EC IS A BIT QUICKER
SINCE YESTERDAY`S 12Z RUN. THE GFS HAS COME INTO BETTER AGREEMENT
WITH THE EC IN ITS LAST COUPLE RUNS...06Z/12Z...THOUGH IS STILL
SLOWER THAN THE EC...AS IT KEEPS THE S/W OVER THE DAKOTAS BY 12Z
SUNDAY. GLBLGEM IS IN LINE WITH THE EC TOO THOUGH IS A BIT SLOWER.
WITH ALL THAT SAID I DECIDED NOT TO DELAY PRECIPITATION ON SUNDAY
AND KEEP IT ARRIVING SUNDAY MORNING(12Z)...THOUGH I WOULDN`T BE
SURPRISED IF PRECIPITATION HELD OFF TILL SUNDAY AFTERNOON AS TIMING
STILL LOOKS TO BE UNCERTAIN. WITH ARRIVAL OF COLDER AIR...-13 TO -14
850MB TEMPS...AND WEST TO NW FLOW KEPT PRECIP FOR DAY 6 THROUGH 12Z
DAY 7 FOR THE NORTH HALF OF THE FA. RIDGING THEN BUILDS IN WEDNESDAY
SO LEFT THE FCST DRY FROM 12Z WED ON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
ROLFSON (UPDATE)
JV (SHORT TERM)
PEARSON (LONG TERM)
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
AFDMQT 345 PM EST TUE JAN 2 2007
.SYNOPSIS...
20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED NEARLY
ZONAL FLOW ACROSS THE NORTHERN U.S. AND SOUTHERN CANADA. PLENTY OF
MOISTURE STREAMING FROM THE CENTRAL PACIFIC INTO THE NORTHERN PLAINS
WITH THIS ZONAL PATTERN...WHICH IS SEEN AS EITHER HIGH BASED
ALTOSTRATUS OR CIRRUS ON VISIBLE SATELLITE IMAGERY. WITHIN THE
FLOW...A FEW SHRTWVS TO NOTE INCLUDE ONE OVER SW MANITOBA AND
ANOTHER IN SW BRITISH COLUMBIA. DUE TO DRY LOW LEVELS SEEN ON THE
12Z INL AND BIS SOUNDINGS (DEWPOINT DEPRESSIONS OF 10C OR MORE FROM
900-500MB)...ALL THE SW MANITOBA SHRTWV HAS BEEN ABLE TO PRODUCE IS
CIRRUS. THE DRY AIR EXTENDS EASTWARD INTO UPPER MICHIGAN...AND WITH
LESS CIRRUS PRESENT AND 925MB TEMPS AROUND 0C...TEMPERATURES HAVE
BEEN ABLE TO CLIMB QUITE A BIT OFF MORNING LOWS. READINGS RIGHT NOW
ARE IN THE MID 30S TO LOW 40S. BASED ON AN 18Z TAMDAR SOUNDING FROM
HOUGHTON AND THESE READINGS...IT APPEARS THAT THE PRESENT MIXING
HEIGHT IS AROUND 940MB. THE RISE IN TEMPERATURES ARE ALSO BEING
HELPED BY SOMEWHAT BREEZY SOUTHWESTERLY WINDS...OCCURRING BETWEEN
1030MB HIGH PRESSURE OVER THE OHIO VALLEY AND A 986MB LOW OVER
NORTHERN MANITOBA. GIVEN THE STRONG INVERSION PRESENT...WINDS ARE
STRONGER JUST OFF THE SURFACE. KMQT VAD WIND PROFILE CONTINUES TO
SHOW WINDS INCREASING AT 2000FT...NOW AT 25 KT. AT CMX...THE
SOUNDING SHOWED 30 KT AT 2000 FT.
&&
.SHORT TERM (TONIGHT AND WED)...
FOR TONIGHT...THE SHRTWV TROUGH OVER SW MANITOBA IS PROGGED TO MOVE
ACROSS NORTHERN ONTARIO. THIS TROUGH...COMBINED WITH THE DIURNAL
NATURE OF THE LOW LEVEL JET...WILL HELP TO CONTINUE STRENGTHENING
WINDS JUST ABOVE THE LAND SURFACE THROUGH THE NIGHT. ALTHOUGH THESE
WINDS WILL BE BRINGING IN WARM AIR ALOFT...ENOUGH INSTABILITY SHOULD
STILL EXIST OVER WESTERN LAKE SUPERIOR TO CREATE GALE FORCE
WINDS...ESPECIALLY WITH THE FUNNELING NATURE OF THE SW WIND ON
WESTERN LAKE SUPERIOR. THEREFORE THE GALE WARNING WILL REMAIN
POSTED. WIND GUSTS FROM THE 13 KM DEV RUC AND 950MB WINDS FROM THE
NAM AND GFS ALSO POINT TO THIS SCENARIO. IN ADDITION...SINCE THE
WIND DIRECTIONS ARE FROM THE SOUTHWEST...AM EXPECTING THAT DOWNSLOPE
LOCATIONS WILL NOT DROP A LOT...PROBABLY RIGHT NEAR FREEZING.
PREVIOUS FORECAST LOWS HAVE THIS WELL IN HAND. HOWEVER...FOR THE
INTERIOR SECTIONS...DID RAISE TEMPERATURES A DEGREE OR TWO AS HIGH
CLOUDS ASSOCIATED WITH THE SHRTWV TROUGH WILL BE OVERSPREADING THE
AREA THROUGH THE EVENING HOURS.
ON WEDNESDAY...UPPER FLOW IS EXPECTED TO REMAIN ZONAL. THEREFORE
DESPITE DNVA AND MID-LEVEL RIDGING BEHIND THE DEPARTING SHRTWV
TROUGH...PLENTY OF CIRRUS OR HIGH BASED ALTOSTRATUS SHOULD PERSIST.
HAVE LOWERED HIGHS A FEW DEGREES FROM THE PREVIOUS FORECAST TO
ACCOUNT FOR MORE CLOUD COVER. NONETHELESS...TEMPERATURES ARE
EXPECTED ABOVE NORMAL TO AROUND RECORD HIGHS AS ENOUGH SUNSHINE
SHOULD STILL GET THROUGH TO RESULT IN MIXING UP TO 940MB. ALTHOUGH
WE CANNOT MIX UP TO THE LEVEL...IT IS INTERESTING TO NOTE THAT BOTH
THE GFS AND NAM SHOW 850MB TEMPS RISING TO AROUND 6C BY 00Z THURSDAY.
.LONG TERM (WED NIGHT THRU TUE)...
WINDS WILL STAY UP WED NIGHT AS FAIRLY TIGHT PRES GRADIENT WILL
COVER THE GREAT LAKES BTWN SFC HIGH PRES NEAR THE SE COAST AND
FAIRLY DEEP LOW PRES OVER SCNTRL CANADA. WILL THUS LEAN TOWARD THE
WARMER ETA MOS NUMBERS FOR MINS. SOME INCREASE/THICKENING OF CLOUDS
WILL ASSIST IN KEEPING TEMPS UP.
ON THU/THU NIGHT...MODELS INDICATE A COMPLICATED MIX OF SHORTWAVE
ENERGY TRACKING THRU THE NRN PLAINS/SCNTRL CANADA IN WSW FLOW. THERE
APPEARS TO BE SOME EMPHASIS ON A SHORTWAVE TRACKING TOWARD UPPER MI
BY THU EVENING. UKMET IS SHARPEST WITH WAVE AND ITS ASSOCIATED SFC
TROF REFLECTION REACHING WRN UPPER MI THU EVENING. ALTHOUGH
WEAKER...THE GLOBAL CANADIAN PROVIDES SUPPORT TO THE OVERALL LOOK OF
THE UKMET. THE GFS HAS A WEAK SFC LOW OVER THE DAKOTAS THU AFTN
WHICH IS CONSISTENT WITH ITS PREVIOUS RUNS. AT THIS POINT...DON`T
THINK THESE DIFFERENCE SERIOUSLY IMPACT PCPN POTENTIAL AS MODELS
SHOW MODEST WAA/ISENTROPIC ASCENT PATTERN DEVELOPING. SHOULD BE SOME
PCPN...BUT ANTECEDENT DRY AIRMASS IN THE LWR MID LEVELS WHICH TENDS
TO HOLD ON AROUND 5KFT PER NAM/GFS FCST SOUNDINGS WILL OBVIOUSLY
PLAY A ROLE IN DELAYING OR EVEN PREVENTING PCPN FROM REACHING THE
SFC. IN THE DRIER LAYER...TEMPS ARE PLENTY WARM ENOUGH TO SUPPORT
LIQUID PCPN (2 TO 4C)...BUT DUE TO THE DRYNESS...WETBULB TEMPS HOVER
AROUND 0C. SO...PROVIDED ENOUGH MOISTENING CAN OCCUR... ANY LIGHT
PCPN THAT DEVELOPS COULD BE RAIN OR SNOW. IF PCPN DEVELOPS EARLY
ENOUGH IN THE DAY PER GFS...-FZRA COULD BE AN ISSUE. HOWEVER...IT
APPEARS THE GFS IS PRODUCING PCPN TOO QUICKLY BASED ON ITS FCST
SOUNDING WHICH REVEAL LINGERING DRY AIR WHEN IT FIRST GENERATES
PCPN. WILL SHOOT FOR LOW CHC POPS FOR -RA/-SN THU AFTN THRU THU
EVENING. WILL THEN DROP POPS BACK TO SLIGHT CHC CATEGORY THU
OVERNIGHT.
TOUGH TO GET A HANDLE ON SITUATION FOR FRI/FRI NIGHT. UKMET/CANADIAN
SUGGEST DRY WEATHER TAKING OVER AS EARLY AS THU NIGHT AND LASTING
THRU FRI BEHIND THEIR SHARPER SHORTWAVE DISCUSSED ABOVE. GFS ALSO
SUGGESTS DRY WEATHER...POSSIBLY BEGINNING THU OVERNIGHT AND
CONTINUING THRU FRI MORNING BEFORE NEXT SHORTWAVE APPROACHES. IN
LIGHT OF INHERITED FCST WHICH HAD CHC POPS FOR -SN/-RA THRU THE DAY
FRI...THE UNCERTAINTIES SUGGEST JUST LOWERING CHC TO SLIGHT CHC FRI
MORNING SINCE THERE IS SOME INDICATION FOR THAT PERIOD TO BE DRY
BASED ON 12Z RUNS. SHORTWAVE TROF WILL THEN MOVE ACROSS THE AREA FRI
NIGHT/SAT MORNING...SUPPORTING CHC POPS WITH TREND TO JUST SNOW AS
PTYPE.
SAT THRU TUE...FAIRLY ACTIVE PATTERN EXPECTED FOR THIS TIME FRAME...
BUT WITH ONLY A SERIES OF WHAT SHOULD BE WEAK SYSTEMS CROSSING THE
AREA TO PROVIDE FREQUENT CHANCES OF LIGHT PCPN. CANADIAN/UKMET/ECWMF
AND GFS ALL SHOW A TENDENCY FOR BROAD MEAN TROFFING DURING THIS TIME
ROUGHLY OVER THE CNTRL CONUS. TIMING SHORTWAVES IN THIS FLOW WILL BE
A PROBLEM...BUT SURPRISINGLY MODELS ARE IN REASONABLE AGREEMENT FOR
THE MOMENT. FIRST SHORTWAVE WILL BE EXITING SAT...AND WILL END -SN
CHC FROM W TO E. AT THIS POINT...IT DOESN`T LOOK COLD ENOUGH FOR ANY
LES. NEXT SHORTWAVE WILL TRACK INTO THE AREA SUN...PROVIDING A CHC
OF -SN. WHILE THERE WILL LIKELY BE A PERIOD OF DRY WEATHER BEHIND
THIS SYSTEM...WILL MAINTAIN CHC -SN/FLURRIES INTO MON WITH
UNCERTAINTIES REGARDING TIMING NEXT SHORTWAVE INTO THE AREA. IN
ADDITION...IT MAY BE COLD ENOUGH FOR SOME LES OFF LAKE SUPERIOR. 00Z
GFS INDICATED THE NEXT SYSTEM COULD BE A DECENT CLIPPER TYPE SNOW
PRODUCER WITH A RESPECTABLE SFC LOW TRACKING THRU CNTRL WI/NRN LWR
MI MON NIGHT. HOWEVER...THERE IS LITTLE CONFIDENCE ON DETAILS FOR A
DAY 6-7 SYSTEM. GFS HAS SINCE BACKED OFF SOME ON THIS SYSTEM. A NEW
DEVELOPMENT IN THE 12Z UKMET/CANADIAN IS FOR SHARPER CNTRL CONUS
TROFFING MON WITH A SFC LOW TRACKING THRU THE UPPER LAKES. EVEN IF
THIS IS OVERDONE...MODEL CONSENSUS SUPPORTS -SN CHC MON/MON NIGHT
WITH MAINLY LES ON TUE. AS FOR TEMPS...THERE WILL CONTINUE TO BE A
LACK OF ARCTIC AIR BUILDING UP OVER SRN CANADA DURING THIS TIME WITH
PACIFIC FLOW STILL DRIVING INTO THE W COAST OF NAMERICA. THUS...
TEMPS WILL REMAIN ABOVE NORMAL HERE (GENERALLY HIGHS MID 20S TO MID
30S WITH THE WARMER READINGS EARLY IN THE PERIOD). DOWN THE ROAD...
THERE HAVE BEEN INDICATIONS THAT RIDGING WILL DEVELOP OVER THE ERN
PACIFIC INTO ALASKA...RELATED TO MJO ACTIVITY. SO THERE MAY BE A
TEMPORARY TRANSITION TO MORE SEASONABLE WINTER WEATHER...PERHAPS
EVEN BLO NORMAL TEMPS AND MORE FREQUENT SNOWS...FOR THE MIDDLE AND
END OF THE MONTH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
GALE WARNING WEST HALF LAKE SUPERIOR.
&&
$$
AJ (SHORT TERM)
ROLFSON (LONG TERM)
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
AFDDTX 105 PM EST TUE JAN 2 2007
.AVIATION...
MAIN PROBLEM THROUGH 18Z THURS WILL BE WINDS AND LOW LEVEL WIND
SHEAR. LOW LEVEL GRADIENT AROUND HIGH PRESSURE ACROSS THE OHIO
VALLEY WILL BEGIN STRENGTHENING ACROSS LOWER MICHIGAN THIS AFTERNOON
AND CONTINUE INTO THURSDAY. WINDS AROUND 925MB OR ABOUT 2000 FEET
AGL INCREASE TO 35KTS ACROSS THE SAGINAW VALLEY EARLY TONIGHT AND
EXPAND SOUTHWARD TOWARDS THE DETROIT AREA BY 09Z. WITH GENERALLY
CLEAR SKIES AND LOW DEWPOINTS ALONG WITH WARM AIR ADVECTION
ALOFT...EXPECT ENOUGH SURFACE RADIATIONAL COOLING EARLY TONIGHT TO
DECOUPLE BOUNDARY LAYER. THIS SHOULD KEEP WIND SPEEDS DOWN SOMEWHAT
WHILE WINDS AT AND ABOVE SURFACE INVERSION INCREASE. THIS WILL LEAD
TO LOW LEVEL WIND SHEAR ACROSS SOUTHEAST LOWER MICHIGAN.
MIXING AFTER SUNRISE THURSDAY WILL INCREASE SURFACE WINDS AND GUSTS
STARTING ABOUT 14Z.
VISIBILITIES AND CEILINGS WILL REMAIN WELL VFR THROUGH 18Z THURS AS
ONLY CLOUDS WILL BE SCT-BKN AC AND CI DECK THROUGH ABOUT 06Z
ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE.
&&
.PREV DISCUSSION...ISSUED 320 AM EST TUE JAN 2 2007
SHORT TERM...TODAY AND TONIGHT
QUITE WEATHER PATTERN TO CONTINUE THROUGH THE SHORT TERM PERIOD.
SURFACE HIGH PRESSURE OVER THE THE CENTRAL AND SOUTHERN GREAT LAKES
WILL SLOWLY DROP SOUTH TODAY. THIS WILL ALLOW THE SOUTHWEST RETURN
FLOW TO STRENGTHEN...INCLUDING SOME WEAK ISENTROPIC LIFT THIS
AFTERNOON. SATELLITE IR LOOP SHOWS SOME HIGH AC MOVING ACROSS
WISCONSIN ASSOCIATE WITH SOME WEAK RETURN FLOW ISENTROPIC LIFT AS
NOTED ON THE 300K SURFACE. THIS AREA OF MID LEVEL CLOUD TO AFFECT
THE CWA TODAY AND HOLD TEMPERATURES DOWN A BIT. HOWEVER 850 MB TEMPS
WARM 4 DEGREES TODAY AND EVEN WITH SCATTERED TO BROKEN CLOUD COVER
ANTICIPATE TEMPERATURES TO RISE AT LEAST INTO THE MID 40S.
ANTICIPATE SOME OF THIS CLOUD TO COVER TO BREAK UP THOUGH AS MODELS
SHOW UPPER CONFLUENCE INCREASING TODAY...SO WILL HAVE TO KEEP AN EYE
ON THE TEMPERATURES.
SCATTERED TO BROKEN CLOUD COVER TO BE REINFORCED THIS EVENING AS A
WEAK UPPER WAVE MOVES THROUGH THE REGION. THIS WAVE IS CURRENT OVER
THE NORTHERN PLAINS AND PRODUCING VERY LITTLE CLOUD COVER THOUGH.
COMBINATION OF AT LEAST EVENING CLOUD COVER AND INCREASING SURFACE
GRADIENT AS HIGH DROPS SOUTH...SHOULD KEEP TEMPS UP TONIGHT...SO
WILL CONTINUE WITH LOWS ONLY AROUND 30 AT THIS TIME.
LONG TERM...
MILD SOUTHWEST FLOW WILL BE THE RULE WEDNESDAY-FRIDAY WITH
MOISTURE ALSO ON THE INCREASE AS A RESULT. LOTS OF ENERGY OVER THE
EASTERN PACIFIC...AS SATELLITE/AIRCRAFT ESTIMATES INDICATE A 180
KNOT UPPER LEVEL JET (250 MB) OFF THE SOUTHERN BRITISH COLUMBIA
COAST. THE 00Z GFS INITIALIZATION SEEMED TO BEST REPRESENT THIS
JET. THE UNCERTAINTY OF THE FORECAST REALLY BEGINS TO RAMP UP BY
LATE THURSDAY...AS THERE ARE BIG DIFFERENCES WITH THE HANDLING OF
THE PACIFIC ENERGY/SHORTWAVES. ALTHOUGH THE CUTOFF LOW OVER
ARIZONA MAY NOT DIRECTLY IMPACT SOUTHEAST MICHIGAN...STILL
CONCERNS FOR RAIN THURSDAY NIGHT WITH THE NORTHERN STREAM
SHORTWAVE TRACKING THROUGH THE NORTHERN GREAT LAKES...AS SOUTHEAST
MICHIGAN IS CAUGHT UNDERNEATH THE RIGHT ENTRANCE REGION OF AN
INCREASING UPPER LEVEL JET (140+ KNOTS) FRIDAY MORNING...PER 12Z
GFS. THE 00Z CANADIAN GLOBAL IS MUCH MORE PRONOUNCED AND FARTHER
SOUTH WITH THE NORTHERN STREAM WAVE...WHILE THE 00Z UKMET IS ALSO
INDICATING A STRONG UPPER WAVE TRACKING THROUGH LAKE
MICHIGAN...BUT MUCH FASTER (00Z FRIDAY). MEANWHILE...THE 00Z
EUROPEAN INDICATES A WEAK NORTHERN STREAM WAVE AT BEST MOVING
THROUGH...BUT BRINGS THE SOUTHERN UPPER LOW FARTHEST
NORTH...IMPACTING SOUTHEAST MICHIGAN BY FRIDAY...AS THE SURFACE
LOW TRACKS OVER LAKE ERIE.
UNFORTUNATELY...THE GFS ENSEMBLE MEMBERS ARE NOT A HUGE HELP FOR
THURSDAY NIGHT...AS ABOUT HALF ARE DRY OR BASICALLY DRY (A COUPLE
HUNDREDTHS) WITH THE OTHER HALF INDICATING AT LEAST A TENTH OF AN
INCH QPF TO OVER A QUARTER OF AN INCH...HIGHEST AMOUNTS ACROSS THE
FAR SOUTHEAST PART OF THE CWA. WITH ALL THAT INFORMATION...PLANNING
ON CARRYING A SLIGHT CHANCE ACROSS THE NORTH HALF OF THE CWA
THURSDAY NIGHT...WITH CHANCE POPS SOUTH. WILL MAINTAIN THE CURRENT
CHANCE POPS FOR FRIDAY.
MEDIUM RANGE MODELS HAVE A LITTLE BETTER SUPPORT/AGREEMENT AS WE
HEAD INTO SATURDAY WITH BROAD UPPER LEVEL TROUGH/SURFACE COLD FRONT
SWINGING THROUGH THE CENTRAL GREAT LAKES...ALTHOUGH TIMING
DIFFERENCES STILL ABOUND WHICH WILL HAVE A BIG IMPACT ON MAXES.
WE HAVE A 40 POP GOING AND SEE NO REASON TO DEVIATE AT THIS TIME
WITH MAXES IN THE MID 40S...WHICH ARE GENERALLY IN LINE WITH THE
GFSX MOS GUIDANCE. ALTHOUGH...THE TREND OF THE FROPA IS A LITTLE
FASTER BASED ON THE 00Z GFS/EUROPEAN/CANADIAN GLOBAL. WILL ALLOW FOR
A POSSIBLE CHANGEOVER TO SNOW LATE IN THE DAY. MAXES SHOULD OCCUR
EARLY IN THE DAY AND THEN FALL DURING THE AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 10 AM TUESDAY.
SMALL CRAFT ADVISORY...LHZ421 UNTIL 7 AM TUESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...GSS
AVIATION.....DRC
LONG TERM....SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
AFDDTX 605 AM EST TUE JAN 2 2007
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE TAF FORECAST PERIOD. HIGH
PRESSURE OVER THE LOWER GREAT LAKES WILL SLOWLY DROP SOUTH INTO THE
OHIO VALLEY TODAY AND TONIGHT. AS A RESULT SOUTHWEST RETURN FLOW
WILL DEVELOP OVER THE REGION...WITH SOME ASSOCIATED ISENTROPIC LIFT
PRODUCING SOME MID LEVEL CLOUDS. ANTICIPATE BROKEN AC DECK 100-120
BETWEEN 16-22Z. REINFORCING SURGE OF MID LEVEL CLOUDS EXPECTED
BETWEEN 02-08Z AS WEAK UPPER WAVE MOVES THROUGH THE LOWER GREAT
LAKES. SURFACE WINDS EXPECTED TO INCREASE TO AROUND 15KTS
18-22Z...AS SURFACE GRADIENT STRENGTHENS OVER THE LOWER GREAT LAKES.
&&
.PREV DISCUSSION...ISSUED 320 AM EST TUE JAN 2 2007
SHORT TERM...TODAY AND TONIGHT
QUITE WEATHER PATTERN TO CONTINUE THROUGH THE SHORT TERM PERIOD.
SURFACE HIGH PRESSURE OVER THE THE CENTRAL AND SOUTHERN GREAT LAKES
WILL SLOWLY DROP SOUTH TODAY. THIS WILL ALLOW THE SOUTHWEST RETURN
FLOW TO STRENGTHEN...INCLUDING SOME WEAK ISENTROPIC LIFT THIS
AFTERNOON. SATELLITE IR LOOP SHOWS SOME HIGH AC MOVING ACROSS
WISCONSIN ASSOCIATE WITH SOME WEAK RETURN FLOW ISENTROPIC LIFT AS
NOTED ON THE 300K SURFACE. THIS AREA OF MID LEVEL CLOUD TO AFFECT
THE CWA TODAY AND HOLD TEMPERATURES DOWN A BIT. HOWEVER 850 MB TEMPS
WARM 4 DEGREES TODAY AND EVEN WITH SCATTERED TO BROKEN CLOUD COVER
ANTICIPATE TEMPERATURES TO RISE AT LEAST INTO THE MID 40S.
ANTICIPATE SOME OF THIS CLOUD TO COVER TO BREAK UP THOUGH AS MODELS
SHOW UPPER CONFLUENCE INCREASING TODAY...SO WILL HAVE TO KEEP AN EYE
ON THE TEMPERATURES.
SCATTERED TO BROKEN CLOUD COVER TO BE REINFORCED THIS EVENING AS A
WEAK UPPER WAVE MOVES THROUGH THE REGION. THIS WAVE IS CURRENT OVER
THE NORTHERN PLAINS AND PRODUCING VERY LITTLE CLOUD COVER THOUGH.
COMBINATION OF AT LEAST EVENING CLOUD COVER AND INCREASING SURFACE
GRADIENT AS HIGH DROPS SOUTH...SHOULD KEEP TEMPS UP TONIGHT...SO
WILL CONTINUE WITH LOWS ONLY AROUND 30 AT THIS TIME.
LONG TERM...
MILD SOUTHWEST FLOW WILL BE THE RULE WEDNESDAY-FRIDAY WITH
MOISTURE ALSO ON THE INCREASE AS A RESULT. LOTS OF ENERGY OVER THE
EASTERN PACIFIC...AS SATELLITE/AIRCRAFT ESTIMATES INDICATE A 180
KNOT UPPER LEVEL JET (250 MB) OFF THE SOUTHERN BRITISH COLUMBIA
COAST. THE 00Z GFS INITIALIZATION SEEMED TO BEST REPRESENT THIS
JET. THE UNCERTAINTY OF THE FORECAST REALLY BEGINS TO RAMP UP BY
LATE THURSDAY...AS THERE ARE BIG DIFFERENCES WITH THE HANDLING OF
THE PACIFIC ENERGY/SHORTWAVES. ALTHOUGH THE CUTOFF LOW OVER
ARIZONA MAY NOT DIRECTLY IMPACT SOUTHEAST MICHIGAN...STILL
CONCERNS FOR RAIN THURSDAY NIGHT WITH THE NORTHERN STREAM
SHORTWAVE TRACKING THROUGH THE NORTHERN GREAT LAKES...AS SOUTHEAST
MICHIGAN IS CAUGHT UNDERNEATH THE RIGHT ENTRANCE REGION OF AN
INCREASING UPPER LEVEL JET (140+ KNOTS) FRIDAY MORNING...PER 12Z
GFS. THE 00Z CANADIAN GLOBAL IS MUCH MORE PRONOUNCED AND FARTHER
SOUTH WITH THE NORTHERN STREAM WAVE...WHILE THE 00Z UKMET IS ALSO
INDICATING A STRONG UPPER WAVE TRACKING THROUGH LAKE
MICHIGAN...BUT MUCH FASTER (00Z FRIDAY). MEANWHILE...THE 00Z
EUROPEAN INDICATES A WEAK NORTHERN STREAM WAVE AT BEST MOVING
THROUGH...BUT BRINGS THE SOUTHERN UPPER LOW FARTHEST
NORTH...IMPACTING SOUTHEAST MICHIGAN BY FRIDAY...AS THE SURFACE
LOW TRACKS OVER LAKE ERIE.
UNFORTUNATELY...THE GFS ENSEMBLE MEMBERS ARE NOT A HUGE HELP FOR
THURSDAY NIGHT...AS ABOUT HALF ARE DRY OR BASICALLY DRY (A COUPLE
HUNDREDTHS) WITH THE OTHER HALF INDICATING AT LEAST A TENTH OF AN
INCH QPF TO OVER A QUARTER OF AN INCH...HIGHEST AMOUNTS ACROSS THE
FAR SOUTHEAST PART OF THE CWA. WITH ALL THAT INFORMATION...PLANNING
ON CARRYING A SLIGHT CHANCE ACROSS THE NORTH HALF OF THE CWA
THURSDAY NIGHT...WITH CHANCE POPS SOUTH. WILL MAINTAIN THE CURRENT
CHANCE POPS FOR FRIDAY.
MEDIUM RANGE MODELS HAVE A LITTLE BETTER SUPPORT/AGREEMENT AS WE
HEAD INTO SATURDAY WITH BROAD UPPER LEVEL TROUGH/SURFACE COLD FRONT
SWINGING THROUGH THE CENTRAL GREAT LAKES...ALTHOUGH TIMING
DIFFERENCES STILL ABOUND WHICH WILL HAVE A BIG IMPACT ON MAXES.
WE HAVE A 40 POP GOING AND SEE NO REASON TO DEVIATE AT THIS TIME
WITH MAXES IN THE MID 40S...WHICH ARE GENERALLY IN LINE WITH THE
GFSX MOS GUIDANCE. ALTHOUGH...THE TREND OF THE FROPA IS A LITTLE
FASTER BASED ON THE 00Z GFS/EUROPEAN/CANADIAN GLOBAL. WILL ALLOW FOR
A POSSIBLE CHANGEOVER TO SNOW LATE IN THE DAY. MAXES SHOULD OCCUR
EARLY IN THE DAY AND THEN FALL DURING THE AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 10 AM TUESDAY.
SMALL CRAFT ADVISORY...LHZ421 UNTIL 7 AM TUESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...GSS
AVIATION.....GSS
LONG TERM....SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
AFDDTX 320 AM EST TUE JAN 2 2007
.SHORT TERM...TODAY AND TONIGHT
QUITE WEATHER PATTERN TO CONTINUE THROUGH THE SHORT TERM PERIOD.
SURFACE HIGH PRESSURE OVER THE THE CENTRAL AND SOUTHERN GREAT LAKES
WILL SLOWLY DROP SOUTH TODAY. THIS WILL ALLOW THE SOUTHWEST RETURN
FLOW TO STRENGTHEN...INCLUDING SOME WEAK ISENTROPIC LIFT THIS
AFTERNOON. SATELLITE IR LOOP SHOWS SOME HIGH AC MOVING ACROSS
WISCONSIN ASSOCIATE WITH SOME WEAK RETURN FLOW ISENTROPIC LIFT AS
NOTED ON THE 300K SURFACE. THIS AREA OF MID LEVEL CLOUD TO AFFECT
THE CWA TODAY AND HOLD TEMPERATURES DOWN A BIT. HOWEVER 850 MB TEMPS
WARM 4 DEGREES TODAY AND EVEN WITH SCATTERED TO BROKEN CLOUD COVER
ANTICIPATE TEMPERATURES TO RISE AT LEAST INTO THE MID 40S.
ANTICIPATE SOME OF THIS CLOUD TO COVER TO BREAK UP THOUGH AS MODELS
SHOW UPPER CONFLUENCE INCREASING TODAY...SO WILL HAVE TO KEEP AN EYE
ON THE TEMPERATURES.
SCATTERED TO BROKEN CLOUD COVER TO BE REINFORCED THIS EVENING AS A
WEAK UPPER WAVE MOVES THROUGH THE REGION. THIS WAVE IS CURRENT OVER
THE NORTHERN PLAINS AND PRODUCING VERY LITTLE CLOUD COVER THOUGH.
COMBINATION OF AT LEAST EVENING CLOUD COVER AND INCREASING SURFACE
GRADIENT AS HIGH DROPS SOUTH...SHOULD KEEP TEMPS UP TONIGHT...SO
WILL CONTINUE WITH LOWS ONLY AROUND 30 AT THIS TIME.
&&
.LONG TERM...
MILD SOUTHWEST FLOW WILL BE THE RULE WEDNESDAY-FRIDAY WITH
MOISTURE ALSO ON THE INCREASE AS A RESULT. LOTS OF ENERGY OVER THE
EASTERN PACIFIC...AS SATELLITE/AIRCRAFT ESTIMATES INDICATE A 180
KNOT UPPER LEVEL JET (250 MB) OFF THE SOUTHERN BRITISH COLUMBIA
COAST. THE 00Z GFS INITIALIZATION SEEMED TO BEST REPRESENT THIS
JET. THE UNCERTAINTY OF THE FORECAST REALLY BEGINS TO RAMP UP BY
LATE THURSDAY...AS THERE ARE BIG DIFFERENCES WITH THE HANDLING OF
THE PACIFIC ENERGY/SHORTWAVES. ALTHOUGH THE CUTOFF LOW OVER
ARIZONA MAY NOT DIRECTLY IMPACT SOUTHEAST MICHIGAN...STILL
CONCERNS FOR RAIN THURSDAY NIGHT WITH THE NORTHERN STREAM
SHORTWAVE TRACKING THROUGH THE NORTHERN GREAT LAKES...AS SOUTHEAST
MICHIGAN IS CAUGHT UNDERNEATH THE RIGHT ENTRANCE REGION OF AN
INCREASING UPPER LEVEL JET (140+ KNOTS) FRIDAY MORNING...PER 12Z
GFS. THE 00Z CANADIAN GLOBAL IS MUCH MORE PRONOUNCED AND FARTHER
SOUTH WITH THE NORTHERN STREAM WAVE...WHILE THE 00Z UKMET IS ALSO
INDICATING A STRONG UPPER WAVE TRACKING THROUGH LAKE
MICHIGAN...BUT MUCH FASTER (00Z FRIDAY). MEANWHILE...THE 00Z
EUROPEAN INDICATES A WEAK NORTHERN STREAM WAVE AT BEST MOVING
THROUGH...BUT BRINGS THE SOUTHERN UPPER LOW FARTHEST
NORTH...IMPACTING SOUTHEAST MICHIGAN BY FRIDAY...AS THE SURFACE
LOW TRACKS OVER LAKE ERIE.
UNFORTUNATELY...THE GFS ENSEMBLE MEMBERS ARE NOT A HUGE HELP FOR
THURSDAY NIGHT...AS ABOUT HALF ARE DRY OR BASICALLY DRY (A COUPLE
HUNDREDTHS) WITH THE OTHER HALF INDICATING AT LEAST A TENTH OF AN
INCH QPF TO OVER A QUARTER OF AN INCH...HIGHEST AMOUNTS ACROSS THE
FAR SOUTHEAST PART OF THE CWA. WITH ALL THAT INFORMATION...PLANNING
ON CARRYING A SLIGHT CHANCE ACROSS THE NORTH HALF OF THE CWA
THURSDAY NIGHT...WITH CHANCE POPS SOUTH. WILL MAINTAIN THE CURRENT
CHANCE POPS FOR FRIDAY.
MEDIUM RANGE MODELS HAVE A LITTLE BETTER SUPPORT/AGREEMENT AS WE
HEAD INTO SATURDAY WITH BROAD UPPER LEVEL TROUGH/SURFACE COLD FRONT
SWINGING THROUGH THE CENTRAL GREAT LAKES...ALTHOUGH TIMING
DIFFERENCES STILL ABOUND WHICH WILL HAVE A BIG IMPACT ON MAXES.
WE HAVE A 40 POP GOING AND SEE NO REASON TO DEVIATE AT THIS TIME
WITH MAXES IN THE MID 40S...WHICH ARE GENERALLY IN LINE WITH THE
GFSX MOS GUIDANCE. ALTHOUGH...THE TREND OF THE FROPA IS A LITTLE
FASTER BASED ON THE 00Z GFS/EUROPEAN/CANADIAN GLOBAL. WILL ALLOW FOR
A POSSIBLE CHANGEOVER TO SNOW LATE IN THE DAY. MAXES SHOULD OCCUR
EARLY IN THE DAY AND THEN FALL DURING THE AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 1147 PM EST MON JAN 1 2007
AVIATION...
TAF FORECASTS FOR THE 06Z ISSUANCE ARE SOLIDLY VFR. GENERALLY
CLEAR SKIES FOR THE REMAINDER OF THIS NIGHT. SOME HIGH AND WARM
ADVECTION MID CLOUDS TUESDAY THINNING TUESDAY EVENING BEHIND MID
LEVEL VORTICITY MAXIMUM CLEARING THE AREA. 00Z MODEL FORECASTS FOR
MOISTURE SHOW VERY DRY CONDITIONS BELOW 10K FEET THROUGH THE
PERIOD...SO NO PRECIPITATION EXPECTED TUESDAY OR TUESDAY EVENING
EVEN WITH SOME SEMBLANCE OF SYNOPTIC SCALE LIFT/ASCENT EXPECTED.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 10 AM TUESDAY.
SMALL CRAFT ADVISORY...LHZ421 UNTIL 7 AM TUESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...GSS
LONG TERM....SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).