Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT" or "AMDAR" received at FSL on 03/15/03


AREA FORECAST DISCUSSION
NWS DODGE CITY KS
AFDDDC 325 PM CST FRI MAR 14 2003

DAYS 1-2... FALLING SFC PRESSURES WITH STRENGTHENING LEE TROF HAVE YIELDED SOUTHWEST WINDS FROM 20-30KTS ACROSS MOST OF CWA BY THIS AFTERNOON. DOESN'T LOOK AS THOUGH WE WILL REACH ADVISORY LEVELS. MOST OF THE GOOD LOW LEVEL MOISTURE HAD BEEN PUSHED WELL INTO CENTRAL TX BY THIS MORNING, BUT ANALYSIS SHOWS LOWER AND MID 50 DEWPOINTS MOVING BACK INTO SOUTHWEST TEXAS, MOVING NORTHWARD. THINK THE MAIN CHALLENGE NEXT COUPLE OF DAYS WILL BE LOW TEMPS (BASED ON RETURNING DEWPOINTS) HIGH TEMPS(BASED ON LONGEVITY OF STRATUS).

FOR TONIGHT, MODELS BRING LEE TROF EAST BEFORE REDEVELOPING BACK NEAR THE COLORADO. DO NOT THINK TROF WILL MOVE EAST AS FAR AS MODELS PREDICT WITHOUT AN UPPER LEVEL FEATURE SO WILL NOT BRING THE WINDS AROUND TO THE NORTHWEST AS MUCH AS MODELS. WILL KEEP SPEEDS MAINLY 15-20 MPH FOR THE CENTRAL AND EAST AND LIGHTER WEST...NEAR TROF. DID NOT TWEAK THE LOWS TOO MUCH AS THEY APPEAR ON TRACK. SHOULD HAVE SOME HIGH CLOUDS MOVE INTO AREA ON SATURDAY. 850MB TEMPS SHOW WE SHOULD GET AT LEAST TO TODAY'S HIGHS, BUT WILL KNOCK A FEW OFF DUE TO A BIT LESS SUN. DELTA T'S ON SATURDAY AFTERNOON RISE TO AROUND 21. MODELS SHOWING SOME CONVERGENCE NEAR THE DRYLINE SATURDAY AFTERNOON. CURRENT GRIDS ALREADY INDICATE 20-30 POP FOR SATURDAY AFTERNOON AND EVENING AND DID NOT ADJUST. THINK WE WILL SEE SOME STRATUS/FOG DEVELOP LATE SATURDAY NIGHT AS LOW LEVEL JET BRING UP GULF MOISTURE. ADDED SOME FOG TO GRIDS FOR LATE SATURDAY NIGHT AND SUNDAY MORNING. RAISED LOWS A BIT, MAINLY OVER THE SOUTHEAST CWA SUNDAY MORNING BASED ON HIGHER DEWPOINTS. FOR HIGHS ON SUNDAY, WILL CONTINUE WITH SIMILAR TEMPS AS SATURDAY. SHOULD STILL HAVE ENOUGH HIGH CLOUDS TO CURTAIL SOME OF THE HEATING AS WELL AS STRATUS/FOG LINGERING TO SLOW DOWN THE HEATING. MODELS CONTINUE WITH DRYLINE EAST OF DDC TOWARD EASTERN EDGE WITH ANOTHER S/W TROF IN THE LATE AFTERNOON. WILL CONTINUE WITH CURRENT 30 POP FOR EASTERN CWA FOR SUNDAY AFTERNOON

DAYS 3-7... ** MAJOR STORM EXPECTED TO IMPACT PORTIONS OF SOUTHWEST KANSAS WITH SEVERE WEATHER, RAIN, HIGH WINDS, AND POSSIBLY SNOW **

THE 12Z SUITE OF THE NUMERICAL MODELS ARE ON A GENERAL CONSENSUS...EXCEPT, ONCE AGAIN, THE GFS. AS PER ACARS DATA AT 12Z, 190-200KT JET STREAK WAS LOCATED BETWEEN 35-37N LATITUDE, WITH S/W CYCLONE DEVELOPMENT IN LEFT EXIT REGION THIS AFTERNOON AROUND 42N/135W. UPSTREAM OF THIS AND JUST POLEWARD OF THE 200KT JET, WV LOOP SHOWS PRONOUNCED, NARROW BAND OF DRYING, INDICATING FAIRLY IMPRESSIVE CHANNEL OF HIGH VORTICITY AIR. THIS WILL CONTINUE TO DIVE EAST SOUTHEASTWARD INTO SOUTHERN CALIFORNIA WITH TIME. ANOTHER LEAD S/W TROUGH WILL INDUCE LEE CYCLOGENESIS OVER COLORADO. THE GFS THEN INDUCES SIGNIFICANT CYCLOGENESIS WITH THIS LEAD S/W TROF AND MOVES IT ON EASTWARD MUCH MORE RAPIDLY THEN ALL OTHER MODELS. A MORE PREFERRED SOLUTION WOULD BE THE SFC/H85/H7 CYCLOGENESIS SCENARIO DEPICTED BY 84H ETA, UKMET, NOGAPS, AND CANADIAN MODEL. THE ETA MODEL SHOWS VERY LOW STATIC STABILITY IN THE H5-H7 LAYER AS LEESIDE LOW BEGINS TO UNDER CYCLOGENESIS SUNDAY NIGHT.

THREAT FOR SVRWX EXISTS FOR EASTERN PORTIONS OF CWA SUNDAY NIGHT AS SFC LOW BEGINS TO TAKE SHAPE OVER SOUTHEAST COLORADO. IMPRESSIVE Q-G ASCENT WITH APPROACH OF SOUTHWEST VORT MAX SHOULD BE MORE THAN SUFFICIENT TO INITIATE CONVECTION. INITIALLY, VERTICAL SHEAR PROFILES WILL BE RELATIVELY MARGINAL, BUT WILL INCREASE LATE SUNDAY NIGHT. SFC LOW WILL NOT MOVE MUCH, BUT DEEPEN RAPIDLY ON MONDAY. THE PROGGED PLACEMENT OF THE LOW MAY KEEP A MAJORITY OF THE CWA IN DRY SLOT, BUT AT THIS TIME, THIS IS TOO EARLY TO CALL FOR SURE. WITH INCREASED SHEAR PROFILES, CONVECTION WOULD LIKELY BE MUCH BETTER ORGANIZED OVER EASTERN CWA MONDAY. ETA CAPES ARE PROGGED TO BE RATHER LOW, BUT THIS IS LIKELY A FUNCTION OF ONGOING CONVECTION.

SIGNIFICANT H5/H7 LOW DEVELOPMENT TO THE SOUTH OF CWA WOULD PUT A MAJORITY OF CWA IN GOOD PCPN AREA THROUGH MUCH OF THE DAY TUESDAY. LATE TUESDAY, IT IS STILL UNCLEAR HOW MUCH COLD AIR CAN FILTER DOWN THE HIGH PLAINS, BUT IT IS EXPECTED THAT SIGNIFICANT AGEOSTROPHIC LOW LEVEL FLOW WILL RAPIDLY ADVECT COLD AIR SOUTHWARD, AS WELL AS ADDITIONAL COOLING FROM DYNAMIC PROCESSES. PUSHED THE RAIN/SNOW BACK TO TUESDAY NIGHT FOR NORTHERN CWA.

SOMETHING ELSE TO CONSIDER IS THE AMOUNT OF WIND BEHIND THE SFC LOW. COULD SEE HIGH WIND WARNING CRITERIA BREACHED TUESDAY/TUESDAY NIGHT IF SFC LOW BOMBS OUT OVER NORTHERN OK/SOUTHEAST KS, AND IF SNOW IS ASSOCIATED WITH THIS, IT COULD BECOME RATHER INTERESTING.

PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE CONTAINED WITHIN THE DODGE CITY ZONE FORECAST.

DDC 49 78 49 78 / 0 20 20 30 GCK 48 77 44 78 / 0 0 0 0 EHA 48 76 41 77 / 0 0 0 0 LBL 50 79 45 78 / 0 0 0 0 HYS 47 78 46 75 / 0 20 0 30 P28 52 78 54 78 / 0 30 30 30

.DDC...NONE.

FCSTID = 15/25




AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
AFDSDF 315 PM EST FRI MAR 14 2003

CLOUDS WERE SLOW TO DECREASE THIS MORNING BUT LOW CLOUDS OVER MOST OF FORECAST AREA HAVE DECREASED EXCEPT FOR THE SOUTH NEAR THE TENNESSEE BORDER. TEMPERATURES ARE REBOUNDING AND MAY REACH THE MID 50S BY LATE AFTERNOON.

FORECAST CHALLENGES THIS FORECAST WILL BE RETURN/REDEVELOPMENT OF CLOUDS TONIGHT AND THE CHANCES OF PRECIPITATION OVER THE WEEKEND.

MODELS GENERALLY SIMILAR BUT GFS IS FASTER WITH SPEED OF LOW MOVING OUT OVER THE WEEKEND. WILL LEAN MORE TOWARD GFS AS IT HAS BEEN MORE CONSISTENT PER NCEP DISCUSSION.

FOR THE SHORT TERM...MOST OF LOW CLOUDS HAVE DISSIPATED WITH REMAINING CLOUDS ALONG TENNESSEE BORDER EXPECTED TO SCATTER OUT DURING THE LATE AFTERNOON. HOWEVER MOISTURE PERSISTS IN THE LOWER LEVELS AND MODEL RH AT 925 MB INCREASES DURING THE OVERNIGHT HOURS. AIRCRAFT SOUNDINGS INDICATE LOW LEVEL INVERSION STILL PRESENT AT 1730Z. WILL ALLOW LOW CLOUDS TO REDEVELOP AND WITH CIRRUS STILL OVER THE AREA CLOUDS WILL INCREASE OVERNIGHT.

ON SATURDAY LOW PRESSURE MOVING NORTHEAST FROM GULF STATES WILL KEEP MOSTLY CLOUDY SKIES OVER CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA. WITH WINDS BECOMING MORE SOUTHERLY AHEAD OF THE SURFACE LOW...EXPECT TEMPERATURES TO WARM INTO THE LOWER AND MID 60S EVEN WITH THE CLOUD COVER.

IN THE LONGER TERM...THE MAIN QUESTION IS FOR SHOWERS SATURDAY NIGHT. MODELS TRY TO BRING IN A FEW HUNDREDTHS OF AN INCH AS THE LOW MOVES TO OUR SOUTHEAST. MOS GUIDANCE ALSO BRINGS IN SMALL POPS BUT WITH RAIN AMOUNTS BEING SO SMALL WILL KEEP DRY FOR NOW. THIS ALSO MATCHES UP BETTER WITH COUNTIES TO THE EAST.

CLOUDS WILL SLOWLY DECREASE SOME SUNDAY/SUNDAY NIGHT AND STAY PARTLY CLOUDY AND MILD THROUGH MONDAY INTO TUESDAY. THIS IS A LITTLE LESS CLOUD COVER THAN SHOWN ON GFS TIME SECTIONS BUT GFS TENDS TO BE A LITTLE HIGH ON RH SO WILL LEAN TOWARD PARTLY CLOUDY.

THEN THE NEXT MAJOR STORM COMES IN TUESDAY NIGHT/WEDNESDAY. WINDS WILL BE BRISK AHEAD OF THIS SYSTEM...PUMPING UP A LOT OF MOISTURE. GFS SHOWS AIR BECOMING UNSTABLE AND WILL HAVE TO WATCH THIS NEXT WEEK FOR POSSIBLE STRONG THUNDERSTORMS.

MILD TEMPERATURES (NEARER TO SEASONAL NORMALS) WILL CONTINUE THROUGH THE WEEK.

.SDF...NONE.

$$ SCHOLZ




SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION...COR FOR HIGHLIGHT
NWS BILLINGS MT
AFDBIL 325 AM MST SAT MAR 15 2003

.SHORT TERM...VALID FOR TDY AND SUN...

SHORT WAVE TROUGH PASSING THROUGH FAR EASTERN MONTANA WILL EXIT QUICKLY THIS MORNING WITH SUNNY SKIES BEHIND IT. SUNSHINE WILL BE SHORT LIVED HOWEVER AS ANOTHER TROUGH WILL HEAD INTO THE AREA THIS AFTERNOON. 04Z ACARS SHOWED COOLING TOOK PLACE AT 800-700MB SINCE THIS AFTERNOON AND WAS COOLER THAN THE ETA/GFS. HOWEVER...BOTH THE ETA/GFS BUILD A THERMAL RIDGE BACK INTO THE AREA. GIVEN THE CONSISTENT WARM BIAS THE MODELS HAVE HAD THE LAST SEVERAL DAY...WILL UNDERCUT MODEL GUIDANCE. THE EAST WILL BE TOUGHEST TEMP WISE TODAY AS SOME LOCATIONS DIDN'T BREAK THEIR LOW LEVEL INVERSIONS AND WERE 15 DEGREES COOLER THAN EXPECTED. DESPITE THIS...WILL BUY INTO THE IDEA THAT THE INVERSIONS WILL BREAK TODAY.

THE SHORT WAVE MOVING THROUGH LATE TODAY WILL WEAKEN AS IT CROSSES THE STATE SO ONLY EXPECT SOME CLOUDS THIS AFTERNOON THROUGH TONIGHT. ANOTHER WAVE WILL HEAD INTO THE AREA SUNDAY. MODELS ARE NOT IN AGREEMENT WITH THIS NEXT FEATURE. THE GFS SEEMS TO HAVE INITIALIZED BETTER THAN THE ETA OVER THE PACIFIC...BUT THE ETA HAS BEEN MORE CONSISTENT FROM RUN TO RUN. SO ITS DIFFICULT TO DECIDE WHICH IS THE BEST CHOICE. AFTER COORDINATION WITH SURROUNDING OFFICE...WILL GO WITH CHANCE POPS FOR MOST OF THE CWA SUNDAY. THE MORE SIGNIFICANT WEATHER WILL COME IN THE LATER PERIODS. MOORE

.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...

MODELS HAVE CHANGED A LITTLE OVER THE PAST COUPLE OF RUNS AND THE RESULTS ARE SOME VERY IMPRESSIVE QPF VALUES FROM LATE SUNDAY NIGHT THROUGH WEDNESDAY MORNING. ETA AND GFS BOTH INDICATING SOME OF THE SOUTH CENTRAL ZONES PICKING UP MORE THAN A HALF INCH OF LIQUID EVERY 6 HOURS FOR SEVERAL PERIODS IN A ROW. THIS IS BEING GENERATED BY A DEEP UPPER LEVEL TROF THAT PARKS OVER THE WESTERN STATES AND GENERATES A DEEP SURFACE LOW OVER NEBRASKA BY TUESDAY. AN INVERTED TROF EXTENDS NORTH INTO EASTERN MONTANA FROM THIS FEATURE...AND PRECIPITATION IS GENERATED AS DISTURBANCES ROTATE INTO THE AREA FROM THE SOUTHEAST AROUND THIS FEATURE. IN ADDITION TO THE IMPRESSIVE OMEGA FIELDS...STRONG NORTHERLY FLOW UP TO 700MB WILL PROVIDE GOOD UPSLOPE PRECIPITATION GENERATION. THE PREVIOUS MODEL RUN WAS NOT AS STRONG WITH THE DIFFLUENCE ALOFT AND ASSOCIATED OMEGA FIELDS BUT STILL HAD GENERAL PREMISE. WRAP AROUND EVENTS LIKE THIS ONE TEND TO BE PROLIFIC PRECIPITATION PRODUCERS... ESPECIALLY ACROSS EASTERN ZONES WHICH IS WHY SURROUNDING OFFICES TO THE EAST HAVE GONE WITH LIKELY PRECIP CHANCES THROUGH WEDNESDAY. GIVEN MODEL INCONSISTENCIES AM A LITTLE HESITANT TO PULL TRIGGER ON LIKELY POPS ALL THE WAY OUT TO WEDNESDAY...BUT IN ORDER TO LINE UP WITH OTHER OFFICES WILL GO AHEAD. PRECIPITATION MAY CHANGE FROM RAIN TO SNOW SEVERAL TIMES DURING THIS TIME FRAME AS TEMPERATURES WILL BE IN THE 30S AND LOWER 40S DURING THE DAY AND 20S TO LOWER 30S AT NIGHT. THE BIG HORNS LOOK TO BE IN A FAVORED POSITION FOR A GOOD DUMPING OF WET SNOW THROUGH MID WEEK. FOR THE PLAINS...TEMPERATURES WILL BE KEY IN DETERMINING IF HEAVY SNOW FALLS OR NOT. WILL HAVE TO WATCH POSITION OF LOW VERY CAREFULLY TO GAUGE WHERE SHARP WRAP AROUND PRECIPITATION GRADIENT WILL FORM. CHAMBERS

TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 060 036/052 032/045 031/040 028/043 026/049 026/052 0/B 03/W 64/O 44/S 43/O 30/E 00/E LVM 058 032/050 028/044 028/041 025/041 023/046 023/049 0/E 24/W 66/O 44/S 43/O 33/E 30/E HDN 058 035/053 031/045 029/041 026/043 024/048 024/050 0/B 03/W 66/O 66/S 63/O 30/E 00/E MLS 057 034/053 030/043 030/038 026/040 024/048 024/051 0/U 03/W 46/O 66/S 60/E 00/E 00/E 4BQ 064 037/055 031/041 029/037 026/039 024/045 024/046 0/U 03/W 66/W 66/S 63/J 30/B 00/B BHK 055 033/052 029/043 027/036 024/037 022/041 022/044 0/U 03/W 46/O 66/S 60/E 00/B 00/B SHR 060 032/053 028/044 027/039 025/040 023/047 023/050 0/B 03/W 66/W 66/S 63/O 30/E 00/E

.BYZ...

FLOOD WARNING TODAY FOR THE TONGUE RIVER SOUTH OF MILES CITY.

WY...NONE.




SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NWS BILLINGS MT
AFDBIL 251 AM MST SAT MAR 15 2003

.SHORT TERM...VALID FOR TDY AND SUN...

SHORT WAVE TROUGH PASSING THROUGH FAR EASTERN MONTANA WILL EXIT QUICKLY THIS MORNING WITH SUNNY SKIES BEHIND IT. SUNSHINE WILL BE SHORT LIVED HOWEVER AS ANOTHER TROUGH WILL HEAD INTO THE AREA THIS AFTERNOON. 04Z ACARS SHOWED COOLING TOOK PLACE AT 800-700MB SINCE THIS AFTERNOON AND WAS COOLER THAN THE ETA/GFS. HOWEVER...BOTH THE ETA/GFS BUILD A THERMAL RIDGE BACK INTO THE AREA. GIVEN THE CONSISTENT WARM BIAS THE MODELS HAVE HAD THE LAST SEVERAL DAY...WILL UNDERCUT MODEL GUIDANCE. THE EAST WILL BE TOUGHEST TEMP WISE TODAY AS SOME LOCATIONS DIDN'T BREAK THEIR LOW LEVEL INVERSIONS AND WERE 15 DEGREES COOLER THAN EXPECTED. DESPITE THIS...WILL BUY INTO THE IDEA THAT THE INVERSIONS WILL BREAK TODAY.

THE SHORT WAVE MOVING THROUGH LATE TODAY WILL WEAKEN AS IT CROSSES THE STATE SO ONLY EXPECT SOME CLOUDS THIS AFTERNOON THROUGH TONIGHT. ANOTHER WAVE WILL HEAD INTO THE AREA SUNDAY. MODELS ARE NOT IN AGREEMENT WITH THIS NEXT FEATURE. THE GFS SEEMS TO HAVE INITIALIZED BETTER THAN THE ETA OVER THE PACIFIC...BUT THE ETA HAS BEEN MORE CONSISTENT FROM RUN TO RUN. SO ITS DIFFICULT TO DECIDE WHICH IS THE BEST CHOICE. AFTER COORDINATION WITH SURROUNDING OFFICE...WILL GO WITH CHANCE POPS FOR MOST OF THE CWA SUNDAY. THE MORE SIGNIFICANT WEATHER WILL COME IN THE LATER PERIODS. MOORE

.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...

MODELS HAVE CHANGED A LITTLE OVER THE PAST COUPLE OF RUNS AND THE RESULTS ARE SOME VERY IMPRESSIVE QPF VALUES FROM LATE SUNDAY NIGHT THROUGH WEDNESDAY MORNING. ETA AND GFS BOTH INDICATING SOME OF THE SOUTH CENTRAL ZONES PICKING UP MORE THAN A HALF INCH OF LIQUID EVERY 6 HOURS FOR SEVERAL PERIODS IN A ROW. THIS IS BEING GENERATED BY A DEEP UPPER LEVEL TROF THAT PARKS OVER THE WESTERN STATES AND GENERATES A DEEP SURFACE LOW OVER NEBRASKA BY TUESDAY. AN INVERTED TROF EXTENDS NORTH INTO EASTERN MONTANA FROM THIS FEATURE...AND PRECIPITATION IS GENERATED AS DISTURBANCES ROTATE INTO THE AREA FROM THE SOUTHEAST AROUND THIS FEATURE. IN ADDITION TO THE IMPRESSIVE OMEGA FIELDS...STRONG NORTHERLY FLOW UP TO 700MB WILL PROVIDE GOOD UPSLOPE PRECIPITATION GENERATION. THE PREVIOUS MODEL RUN WAS NOT AS STRONG WITH THE DIFFLUENCE ALOFT AND ASSOCIATED OMEGA FIELDS BUT STILL HAD GENERAL PREMISE. WRAP AROUND EVENTS LIKE THIS ONE TEND TO BE PROLIFIC PRECIPITATION PRODUCERS... ESPECIALLY ACROSS EASTERN ZONES WHICH IS WHY SURROUNDING OFFICES TO THE EAST HAVE GONE WITH LIKELY PRECIP CHANCES THROUGH WEDNESDAY. GIVEN MODEL INCONSISTENCIES AM A LITTLE HESITANT TO PULL TRIGGER ON LIKELY POPS ALL THE WAY OUT TO WEDNESDAY...BUT IN ORDER TO LINE UP WITH OTHER OFFICES WILL GO AHEAD. PRECIPITATION MAY CHANGE FROM RAIN TO SNOW SEVERAL TIMES DURING THIS TIME FRAME AS TEMPERATURES WILL BE IN THE 30S AND LOWER 40S DURING THE DAY AND 20S TO LOWER 30S AT NIGHT. THE BIG HORNS LOOK TO BE IN A FAVORED POSITION FOR A GOOD DUMPING OF WET SNOW THROUGH MID WEEK. FOR THE PLAINS...TEMPERATURES WILL BE KEY IN DETERMINING IF HEAVY SNOW FALLS OR NOT. WILL HAVE TO WATCH POSITION OF LOW VERY CAREFULLY TO GAUGE WHERE SHARP WRAP AROUND PRECIPITATION GRADIENT WILL FORM. CHAMBERS

TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 060 036/052 032/045 031/040 028/043 026/049 026/052 0/B 03/W 64/O 44/S 43/O 30/E 00/E LVM 058 032/050 028/044 028/041 025/041 023/046 023/049 0/E 24/W 66/O 44/S 43/O 33/E 30/E HDN 058 035/053 031/045 029/041 026/043 024/048 024/050 0/B 03/W 66/O 66/S 63/O 30/E 00/E MLS 057 034/053 030/043 030/038 026/040 024/048 024/051 0/U 03/W 46/O 66/S 60/E 00/E 00/E 4BQ 064 037/055 031/041 029/037 026/039 024/045 024/046 0/U 03/W 66/W 66/S 63/J 30/B 00/B BHK 055 033/052 029/043 027/036 024/037 022/041 022/044 0/U 03/W 46/O 66/S 60/E 00/B 00/B SHR 060 032/053 028/044 027/039 025/040 023/047 023/050 0/B 03/W 66/W 66/S 63/O 30/E 00/E

.BYZ... MT...NONE. WY...NONE.




SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 815 AM PST SAT MAR 15 2003

SYNOPTIC SITUATION...A WET PACIFIC STORM SYSTEM LIES OVER THE REGION THIS MORNING. WINDS AT PIEDRAS BLANCAS TURNED INTO THE NORTHWEST JUST BEFORE 7 THIS MORNING...INDICATING THE TRAILING END OF THE STORM SYSTEM HAS JUST PASSED THROUGH. FROM THERE...A BROAD BAND OF MODERATE RAIN EXTENDS SOUTH TO THE LA BASIN. IN 24 HOURS...THE STORM SYSTEM WILL PUSH INTO ARIZONA...BUT PERSISTENT ONSHORE FLOW...SOME INSTABILITY AND A LOT OF RESIDUAL MOISTURE WILL MEAN THAT THE CHANCE OF SHOWERS WILL BE WITH US THROUGH SUNDAY AND INTO EARLY MONDAY.

THE AREA OF MODERATE TO HEAVY RAINS WILL DRIFT SOUTHWARD DURING THE DAY WITH RAIN DIMINISHING TO SHOWERS OVER SAN LUIS OBISPO COUNTY BY NOON...SANTA BARBARA COUNTY THIS AFTERNOON...VENTURA COUNTY LATER THIS AFTERNOON...AND LA COUNTY THIS EVENING. RAINFALL RATES OF OVER AN INCH PER HOUR HAVE BEEN OBSERVED AND ARE POSSIBLE THROUGH THE DAY WITH THE PASSAGE OF THIS SYSTEM. ACCUMULATIONS ALONG PORTIONS OF THE SANTA YNEZ RANGE THIS MORNING ARE RUNNING 2 TO 4 INCHES...AND THE RAIN CONTINUES TO FALL. SPOTTER REPORTS FROM SANTA BARBARA COUNTY INDICATE THAT SOME ROADS HAVE BEEN CLOSED THIS MORNING DUE TO FLOODING IN THE CITY OF SANTA BARBARA. MINOR FLOODING AND MUDSLIDES ARE LIKELY AND THERE IS A POTENTIAL FOR MORE SERIOUS FLOODING AS THE RAIN CONTINUES. FLOOD WATCHES...WARNINGS...AND ADVISORIES HAVE ALREADY BEEN ISSUED FOR VARIOUS PORTIONS OF THE REGION. SEE FLOOD STATEMENTS FOR DETAILS.

SNOW LEVELS ARE EXPECTED TO REMAIN HIGH THROUGH THE WETTEST PART OF THE STORM. ACARS OUT OF LAX SHOWS THE FREEZING LEVEL AT AROUND 9500 FEET THIS MORNING. SNOW LEVELS IN THE MOUNTAINS ARE EXPECTED TO DROP TODAY TO BETWEEN 5500 AND 6500 FEET TOMORROW MORNING. HEAVY ACCUMULATIOS OF SNOW ARE POSSIBLE ABOVE THE 7000 FOOT LEVEL.

WINDS HAVE NOT BEEN AS STRONG AS EXPECTED WITH THIS SYSTEM...BUT CONDITIONS HAVE STILL BEEN BREEZY AND WINDS ARE EXPECTED TO PICK UP AS THE DAY PROGRESSES. SO WE WILL KEEP THE WIND ADVISORIES IN EFFECT.

EXTENDED...MEDIUM RANGE MODEL AGREEMENT IS LOOKING PRETTY GOOD FOR NEXT WEEK. LOOKS LIKE A MINOR TROUGH WILL MOVE THROUGH THE REGION EARLY MONDAY PRODUCING SOME LIGHT SHOWER ACTIVITY MONDAY MORNING... BUT THEN A RIDGE BUILDS IN LATER MONDAY AND PERSISTS THROUGH WEDNESDAY. SO LOOK FOR CONDITIONS TO IMPROVE ON MONDAY WITH FAIR WEATHER CONTINUING INTO WEDNESDAY. WHILE THE DETAILS DIFFER...BOTH THE ECMWF AND GFS ARE SUGGESTING AN INSIDE SLIDER FOR THURSDAY WITH ANOTHER RIDGE BUILDING IN FOR FRIDAY. THEREFORE...PERHAPS A SLIGHT CHANCE FOR SHOWERS ON THURSDAY...COOLER AND BREEZY...WITH FAIR SKIES EXPECTED AGAIN ON FRIDAY INTO SATURDAY.

LAX +94. DANIELSON

.LOX...FLOOD WARNING (SEE LAXFLWLOX) FLOOD ADVISORY (SEE LAXFLSLOX) FLOOD WATCH (SEE LAXFLSLOX) WIND ADVISORY (SEE LAXNPWLOX) SMALL CRAFT ADVISORY (SEE LAXCWFLOX) HIGH SURF ADVISORY STATEMENT (SEE LAXMWSLOX).




SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NWS BILLINGS MT
AFDBIL 856 AM MST SAT MAR 15 2003

.SHORT TERM...VALID FOR TDY AND SUN...

LOOKING AT THE SOUNDINGS FOR EARLY THIS MORNING...MAX TEMPERATURES FORECAST LOOK REASONABLE. UNFORTUNATELY...NO ACARS SOUNDING FOR BILLINGS REALLY TO CONFIRM THIS PREMISE. DID SOME TINKERING WITH THE WINDS AND TWEAKED A BIT THE EXPRESSIONS FOR THE APPROACHING CLOUD COVER. OTHERWISE...ESSENCE OF GOING FORECAST LOOKS GOOD. CHB

.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...

MODELS HAVE CHANGED A LITTLE OVER THE PAST COUPLE OF RUNS AND THE RESULTS ARE SOME VERY IMPRESSIVE QPF VALUES FROM LATE SUNDAY NIGHT THROUGH WEDNESDAY MORNING. ETA AND GFS BOTH INDICATING SOME OF THE SOUTH CENTRAL ZONES PICKING UP MORE THAN A HALF INCH OF LIQUID EVERY 6 HOURS FOR SEVERAL PERIODS IN A ROW. THIS IS BEING GENERATED BY A DEEP UPPER LEVEL TROF THAT PARKS OVER THE WESTERN STATES AND GENERATES A DEEP SURFACE LOW OVER NEBRASKA BY TUESDAY. AN INVERTED TROF EXTENDS NORTH INTO EASTERN MONTANA FROM THIS FEATURE...AND PRECIPITATION IS GENERATED AS DISTURBANCES ROTATE INTO THE AREA FROM THE SOUTHEAST AROUND THIS FEATURE. IN ADDITION TO THE IMPRESSIVE OMEGA FIELDS...STRONG NORTHERLY FLOW UP TO 700MB WILL PROVIDE GOOD UPSLOPE PRECIPITATION GENERATION. THE PREVIOUS MODEL RUN WAS NOT AS STRONG WITH THE DIFFLUENCE ALOFT AND ASSOCIATED OMEGA FIELDS BUT STILL HAD GENERAL PREMISE. WRAP AROUND EVENTS LIKE THIS ONE TEND TO BE PROLIFIC PRECIPITATION PRODUCERS... ESPECIALLY ACROSS EASTERN ZONES WHICH IS WHY SURROUNDING OFFICES TO THE EAST HAVE GONE WITH LIKELY PRECIP CHANCES THROUGH WEDNESDAY. GIVEN MODEL INCONSISTENCIES AM A LITTLE HESITANT TO PULL TRIGGER ON LIKELY POPS ALL THE WAY OUT TO WEDNESDAY...BUT IN ORDER TO LINE UP WITH OTHER OFFICES WILL GO AHEAD. PRECIPITATION MAY CHANGE FROM RAIN TO SNOW SEVERAL TIMES DURING THIS TIME FRAME AS TEMPERATURES WILL BE IN THE 30S AND LOWER 40S DURING THE DAY AND 20S TO LOWER 30S AT NIGHT. THE BIG HORNS LOOK TO BE IN A FAVORED POSITION FOR A GOOD DUMPING OF WET SNOW THROUGH MID WEEK. FOR THE PLAINS...TEMPERATURES WILL BE KEY IN DETERMINING IF HEAVY SNOW FALLS OR NOT. WILL HAVE TO WATCH POSITION OF LOW VERY CAREFULLY TO GAUGE WHERE SHARP WRAP AROUND PRECIPITATION GRADIENT WILL FORM. CHAMBERS

TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 060 036/052 032/045 031/040 028/043 026/049 026/052 0/B 03/W 64/O 44/S 43/O 30/E 00/E LVM 058 032/050 028/044 028/041 025/041 023/046 023/049 0/E 24/W 66/O 44/S 43/O 33/E 30/E HDN 058 035/053 031/045 029/041 026/043 024/048 024/050 0/B 03/W 66/O 66/S 63/O 30/E 00/E MLS 057 034/053 030/043 030/038 026/040 024/048 024/051 0/U 03/W 46/O 66/S 60/E 00/E 00/E 4BQ 064 037/055 031/041 029/037 026/039 024/045 024/046 0/U 03/W 66/W 66/S 63/J 30/B 00/B BHK 055 033/052 029/043 027/036 024/037 022/041 022/044 0/U 03/W 46/O 66/S 60/E 00/B 00/B SHR 060 032/053 028/044 027/039 025/040 023/047 023/050 0/B 03/W 66/W 66/S 63/O 30/E 00/E

.BYZ... MT...NONE. WY...NONE.