SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 300 PM PST SUN JAN 27 2002
SYNOPTIC SITUATION...IN 24 HOURS...AN UPPER LEVEL LOW OVER VANCOUVER
ISLAND DRIFTS SOUTHEAST TO NORTHERN CALIFORNIA AND A COLD FRONT OVER
SOUTHERN CALIFORNIA WILL MOVE EAST TO ARIZONA. IN 48 HOURS...THE LOW
MOVES SE INTO SRN NV.
DOPPLER RADARS CURRENTLY SHOW THE HEAVIEST SHOWERS WITH THE FRONT OVER
WESTERN VENTURA COUNTY. RAINFALL RATES HAVE BEEN AS HIGH AS 0.56
INCHES IN ONE HOUR EARLIER THIS AFTERNOON NEAR SANTA BARBARA...BUT
MOST RAINFALL HAS BEEN FALLING AT LESS THAN A QUARTER OF AN INCH PER
HOUR. EXPECT THE FRONT TO MOVE THROUGH THE REGION THIS EVENING
PRODUCING ACCUMULATIONS LESS THAN A HALF INCH IN MOST AREAS...BUT SOME
SOUTH FACING SLOPES COULD SEE UP TO 1.25 INCHES. DUE TO OROGAPHICS...
RAIN IS EXPECT TO CONTINUE LINGER OVER LA COUNTY THROUGH MUCH OF
TONIGHT.
SNOW WAS FALLING EARLIER AT MOUNT WILSON WHERE A TRACE WAS MEASURED AT
NOON...AND SANBERG IS OBSERVING SNOW WITH AN AIR TEMP OF +3 DEG C.
LATEST AVAILABLE ACARS SOUNDING HAS FREEZING LEVEL OVR LA BASIN AT
6000 FEET. BUT THIS SHOULD LOWER QUICKLY WITH FRONTAL PASSAGE THIS
EVENING. A SNOW ADVISORY HAS BEEN ISSUED BY NWS SAN DIEGO FOR THEIR
MOUNTAINS...AND ONE WILL LIKELY BE ISSUED BY THIS OFFICE BY 4 PM.
BEHIND THE FRONT...COLD AIR ALOFT WILL MAKE THE ATMOSPHERE UNSTABLE.
SO WHEN THE FRONTAL BAND EXITS OVERNIGHT...EXPECT INSTABILITY SHOWERS
TO DEVELOP ON MONDAY. THESE SHOWERS CAN BE EXPECTED TO CONTINUE INTO
TUESDAY WITH THE APPROACH OF THE UPPER LEVEL LOW. NOTE THAT THE UPPER
LEVEL LOW WILL ALSO BRING BITTER COLD TEMPERATURES TO THE MOUNTAINS
AND VERY CHILLY CONDITIONS ELSEWHERE. MOUNTAIN WIND CHILLS COULD DROP
TO 5 TO 10 DEGREES ABOVE ZERO TONIGHT AND MONDAY NIGHT AND DOWN TO
ZERO TO 10 BELOW TUESDAY NIGHT.
EXTENDED...MRF AND ECMWF IN GOOD AGREEMENT THROUGH THURSDAY MORNING
BEFORE DIVERGING ON FRIDAY AND BEYOND. THE CURRENT SYSTEM LINGERS INTO
TUESDAY BEFORE MOVING EAST. WEDNESDAY AND THURSDAY LOOK FAIR AND
WARMER...BUT BOTH MRF AND ECMWF ARE CALLING FOR ANOTHER SYSTEM LATE IN
THE WEEK. ALTHOUGH THE DETAILS OF THE MODEL SOLUTIONS ARE DIFFERENT...
AT THIS TIME...DOES NOT LOOK AS COLD OR WET AS THIS CURRENT SYSTEM.
WILL LEAVE THE FORECAST AS PARTLY CLOUDY FOR THE TIME BEING.
LAX 8675. DANIELSON.
.LOX...SMALL CRAFT ADVISORY (SEE LAXCWFLAX).
HAZARDOUS WEATHER OUTLOOK (SEE LAXSPSLAX).
AREA FORECAST DISCUSSION
NWS WICHITA KS
AFDICT 330 PM CST SUN JAN 27 2002
MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE TIMING OF THE
FRONT...PRECIP TYPE AND TEMPERATURES.
LATEST WATER VAPOR LOOP SHOWS A WELL DEFINED VORT LOBE PREPARING TO
SLAM INTO THE WEST COAST. WIND FIELDS AHEAD OF THIS TROF ACCORDING
TO ACARS AND PROFILERS ARE ON THE ORDER OF 120-130KTS BETWEEN 200
AND 300MB. THIS IS WELL INITIALIZED BY THE ETA/AVN RUNS. BOTH OF
THESE MODELS ARE ALSO IN FAIRLY GOOD AGREEMENT THROUGH THE FIRST
60HRS ON THE PLACEMENT OF THE UPPER LEVEL TROF. THE MRF APPEARS TO
BE THE OUTLIER IN CUTTING OFF THIS TROF IN THE ROCKIES WHILE THE
ETA/AVN SOLUTION TEND PHASE IT WITH THE NORTHERN STREAM WAVE. LATEST
SFC ANALYSIS IS SHOWING THE FRONT MAKING QUICK PROGRESS SOUTHWARD
THROUGH NB. THIS IS AHEAD OF WHAT THE ETA WAS PROJECTING AT 18Z. AS
A RESULT...WE WILL FOLLOW CLOSEST TO THE ETA SOLUTION THROUGH THE
NEXT COUPLE OF DAYS.
TNGT:
THE ARCTIC FRONT IN NB WILL CONTINUE TO PUSH INTO NORTHERN KS AROUND
DAYBREAK. THERE IS A LITTLE BIT OF LOW LEVEL MOISTURE GETTING
TRAPPED UNDERNEATH THE INVERSION WHICH IS PRODUCING A FEW LOW CLOUDS
IN NB. AS THIS ARCTIC AIR MASS HEADS SOUTH IT SHOULD CONTINUE TO
MODIFY SOME WHICH WILL ALLOW FOR THE LOW LEVEL MOISTURE TO MIX OUT
FAIRLY QUICKLY IN THE MORNING DUE TO A VERY DRY AIR MASS IN PLACE.
TEMPERATURES SHOULD RADIATE OUT FAIRLY WELL TONIGHT AS THE FRONT
APPROACHES WITH ONLY SOME HIGH CLOUDS PRESENT. WE HAVE LOWERED
TEMPERATURES ABOUT A CATEGORY IN ALL LOCATIONS TO REFLECT
RADIATIONAL COOLING WHICH FOLLOWS CLOSE TO GUIDANCE.
TMRW:
THE ETA BRINGS THE FRONT THROUGH CENTRAL KS DURING THE MORNING...BUT
IT IS TENDING TO STALL OUT IN THE SOUTHEAST. THIS IS PROBABLY IN
RESPONSE TO THE UPPER LEVEL TROF DIGGING IN THE SOUTHWEST.
HOWEVER...WITH THE FAST PROGRESSION OF THE COLD FRONT IT MAY GO A
LITTLE FARTHER SOUTH THAT WHAT THE ETA IS PROJECTING. WE HAVE STAYED
CLOSER TO THE PREVIOUS FORECAST SINCE IT TENDS TO BLEND EARLIER WITH
THE ETA RUN.
TMRW NGT:
THE BOUNDARY GRADUALLY SAGS INTO NORTHERN OK. HOW FAR SOUTH THIS
BOUNDARY WILL TRAVEL IS BIG QUESTION MARK AS CYCLOGENIS GETS GEARED
UP IN THE ROCKIES WITH GOOD FRONTOGENISIS SETTING UP ALONG THE
BOUNDARY. WE WILL GO WITH THE PREVIOUS FORECAST ON TEMPERATURES
SINCE THERE WILL MOST LIKELY BE A HUGE GRADIENT SETTING UP WITH THE
TEMPERATURES ALONG WITH GOOD RADIATIONAL COOLING.
TUE AND WED:
WE ARE ONCE AGAIN GOING WITH THE ETA SOLUTION. THE AVN...ECMF...AND
UKMET SOLUTION APPEARS TO PUT THE BOUNDARY TO FAR NORTH. ALL THESE
MODELS ARE PUMPING IN GOOD WARM AIR ADVECTION ABOVE THE BOUNDARY
LAYER WHICH WILL YIELD TO A MIXED BAG OF PRECIP. THE BEST CHANCE
APPEARS TO BE IN THE SOUTH CENTRAL AND SOUTHEAST PART SINCE THEY
WILL BE CLOSER TO THE BOUNDARY AND THE STRONGER ISENTROPIC LIFT
DEPICTED BETWEEN I290-I300K. ENTRANCE REGION OF THE UPPER LEVEL JET
WILL ALSO AID IN THE SITUATION AND PROVIDE AMPLE LIFT. FOR NOW WE
WILL INTRODUCE A CHANCE OF RAIN DURING THE LATE AFTN IN THE SOUTH
CENTRAL AND SOUTHEAST. THEN TUE NGT AND WED WE WILL GO WITH RA TO
FZRA IN THE SOUTH CENTRAL AND SOUTHEAST WITH A MIXED BAG IN THE
NORTH. PRECIP SHOULD CHANGEOVER TO ALL SNOW WED AND WED NIGHT AS THE
UPPER LEVEL TROF AXIS SHIFTS THROUGH.
EXTD:
APPEARS AS IF THE UPPER LEVEL TROF WILL KICK EAST TO THE OHIO VALLEY
AND YIELD TO ZONAL FLOW OVER THE AREA. TEMPERATURES ALSO SHOULD
BEGIN TO RECOVER AFTER THE CLOUDS MOVE OUT ON THURSDAY WITH A GOOD
DOWNSLOPE COMPONENT SETTING UP AGAIN. WE HAVE RAISED TEMPERATURES TO
REFLECT THIS.
THANKS FOR COORDINATION EVERYONE
FCSTID = 18
ICT 39 55 25 37 / 0 0 0 40
HUT 39 55 25 37 / 0 0 0 40
EWK 39 55 25 37 / 0 0 0 40
EQA 39 55 25 37 / 0 0 0 40
WLD 39 55 25 37 / 0 0 0 40
RSL 32 44 21 30 / 0 0 0 0
GBD 32 44 21 30 / 0 0 0 0
SLN 35 47 24 34 / 0 0 0 0
MPR 35 47 24 34 / 0 0 0 0
CFV 43 59 29 42 / 0 0 0 40
CNU 43 59 29 42 / 0 0 0 40
K88 43 59 29 42 / 0 0 0 40
.ICT...NONE.
COX
AREA FORECAST DISCUSSION
NWS WICHITA KS
AFDICT 218 PM CST SUN JAN 27 2002
MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE TIMING OF THE
FRONT...PRECIP TYPE AND TEMPERATURES.
LATEST WATER VAPOR LOOP SHOWS A WELL DEFINED VORT LOBE PREPARING TO
SLAM INTO THE WEST COAST. WIND FIELDS AHEAD OF THIS TROF ACCORDING
TO ACARS AND PROFILERS ARE ON THE ORDER OF 120-130KTS BETWEEN 200
AND 300MB. THIS IS WELL INITIALIZED BY THE ETA/AVN RUNS. BOTH OF
THESE MODELS ARE ALSO IN FAIRLY GOOD AGREEMENT THROUGH THE FIRST
60HRS ON THE PLACEMENT OF THE UPPER LEVEL TROF. THE MRF APPEARS TO
BE THE OUTLIER IN CUTTING OFF THIS TROF IN THE ROCKIES WHILE THE
ETA/AVN SOLUTION TEND PHASE IT WITH THE NORTHERN STREAM WAVE. LATEST
SFC ANALYSIS IS SHOWING THE FRONT MAKING QUICK PROGRESS SOUTHWARD
THROUGH NB. THIS IS AHEAD OF WHAT THE ETA WAS PROJECTING AT 18Z. AS
A RESULT...WE WILL FOLLOW CLOSEST TO THE ETA SOLUTION THROUGH THE
NEXT COUPLE OF DAYS.
TNGT:
THE ARCTIC FRONT IN NB WILL CONTINUE TO PUSH INTO NORTHERN KS AROUND
DAYBREAK. THERE IS A LITTLE BIT OF LOW LEVEL MOISTURE GETTING
TRAPPED UNDERNEATH THE INVERSION WHICH IS PRODUCING A FEW LOW CLOUDS
IN NB. AS THIS ARCTIC AIR MASS HEADS SOUTH IT SHOULD CONTINUE TO
MODIFY SOME WHICH WILL ALLOW FOR THE LOW LEVEL MOISTURE TO MIX OUT
FAIRLY QUICKLY IN THE MORNING DUE TO A VERY DRY AIR MASS IN PLACE.
TEMPERATURES SHOULD RADIATE OUT FAIRLY WELL TONIGHT AS THE FRONT
APPROACHES WITH ONLY SOME HIGH CLOUDS PRESENT. WE HAVE LOWERED
TEMPERATURES ABOUT A CATEGORY IN ALL LOCATIONS TO REFLECT
RADIATIONAL COOLING WHICH FOLLOWS CLOSE TO GUIDANCE.
TMRW:
THE ETA BRINGS THE FRONT THROUGH CENTRAL KS DURING THE MORNING...BUT
IT IS TENDING TO STALL OUT IN THE SOUTHEAST. THIS IS PROBABLY IN
RESPONSE TO THE UPPER LEVEL TROF DIGGING IN THE SOUTHWEST.
HOWEVER...WITH THE FAST PROGRESSION OF THE COLD FRONT IT MAY GO A
LITTLE FARTHER SOUTH THAT WHAT THE ETA IS PROJECTING. WE HAVE STAYED
CLOSER TO THE PREVIOUS FORECAST SINCE IT TENDS TO BLEND EARLIER WITH
THE ETA RUN.
TMRW NGT:
THE BOUNDARY GRADUALLY SAGS INTO NORTHERN OK. HOW FAR SOUTH THIS
BOUNDARY WILL TRAVEL IS BIG QUESTION MARK AS CYCLOGENIS GETS GEARED
UP IN THE ROCKIES WITH GOOD FRONTOGENISIS SETTING UP ALONG THE
BOUNDARY. WE WILL GO WITH THE PREVIOUS FORECAST ON TEMPERATURES
SINCE THERE WILL MOST LIKELY BE A HUGE GRADIENT SETTING UP WITH THE
TEMPERATURES ALONG WITH GOOD RADIATIONAL COOLING.
TUE AND WED:
WE ARE ONCE AGAIN GOING WITH THE ETA SOLUTION. THE AVN...ECMF...AND
UKMET SOLUTION APPEARS TO PUT THE BOUNDARY TO FAR NORTH. ALL THESE
MODELS ARE PUMPING IN GOOD WARM AIR ADVECTION ABOVE THE BOUNDARY
LAYER WHICH WILL YIELD TO A MIXED BAG OF PRECIP. THE BEST CHANCE
APPEARS TO BE IN THE SOUTH CENTRAL AND SOUTHEAST PART SINCE THEY
WILL BE CLOSER TO THE BOUNDARY AND THE STRONGER ISENTROPIC LIFT
DEPICTED BETWEEN I290-I300K. ENTRANCE REGION OF THE UPPER LEVEL JET
WILL ALSO AID IN THE SITUATION AND PROVIDE AMPLE LIFT. FOR NOW WE
WILL INTRODUCE A CHANCE OF RAIN DURING THE LATE AFTN IN THE SOUTH
CENTRAL AND SOUTHEAST. THEN TUE NGT AND WED WE WILL GO WITH RA TO
FZRA IN THE SOUTH CENTRAL AND SOUTHEAST WITH A MIXED BAG IN THE
NORTH. PRECIP SHOULD CHANGEOVER TO ALL SNOW WED AND WED NIGHT AS THE
UPPER LEVEL TROF AXIS SHIFTS THROUGH.
EXTD:
APPEARS AS IF THE UPPER LEVEL TROF WILL KICK EAST TO THE OHIO VALLEY
AND YIELD TO ZONAL FLOW OVER THE AREA. TEMPERATURES ALSO SHOULD
BEGIN TO RECOVER AFTER THE CLOUDS MOVE OUT ON THURSDAY WITH A GOOD
DOWNSLOPE COMPONENT SETTING UP AGAIN. WE HAVE RAISED TEMPERATURES TO
REFLECT THIS.
THANKS FOR COORDINATION EVERYONE
.ICT...NONE.
COX