FXUS63 KTOP 091203
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
603 AM CST WED DEC 9 2009
.UPDATE...
UPDATED FOR 12Z AVIATION.
&&
.DISCUSSION...
SEE PREVIOUS DISCUSSION.
&&
.AVIATION...
MAIN CONCERNS FOR TODAY WILL BE STRONG NORTHWESTERLY WINDS. SPEEDS
SHOULD DIMINISH SLOWLY THROUGH THE DAY...WITH LIGHT WEST WINDS IN
PLACE BY LATE AFTERNOON/EARLY EVENING. WITH HIGH PRESSURE SLIDING
IN SAW NO REASON TO ADD ANOTHER GROUP TO THE END OF THE TAF AS
LIGHT WINDS AND CLEARING SKIES EXPECTED TO CONTINUE OVERNIGHT. 67
&&
.PREV DISCUSSION... /ISSUED 335 AM CST WED DEC 9 2009/
DISCUSSION...
UPPER TROF AXIS WAS FROM THE WESTERN DAKOTAS INTO WESTERN KANSAS AT
0Z WITH EXPECTED 12HR HEIGHT FALLS OF 150M REPORTED AT TOP. 105KT
500MB JET WAS OBSERVED AT DFW...BRINGING A NEGATIVE TILT TO THE
UPPER TROF THIS MORNING AS IT PUSHES QUICKLY EAST. LIGHT SNOW
PERSISTS OVER MUCH OF THE AREA IN SATURATED SNOW GROWTH LAYER
THROUGH MUCH OF THE LOWER AND MIDDLE TROPOSPHERE. VERY STRONG
PRESSURE GRADIENT OVER EASTERN KANSAS AT 8Z WITH NEAR 3-HOUR
PRESSURE RISES OF NEAR 5MB. 500M PROFILER AND RADAR WINDS FROM 40
TO 50KT SUPPORTING SUSTAINED SPEEDS FROM 20 TO 30MPH WITH SOME
GUSTS AROUND 45MPH...RESULTING IN BLOWING AND DRIFTING OF THE
NEARLY FOOT OF SNOW IN NORTHERN AREAS.
GUIDANCE QUITE SIMILAR IN THE PEAK OF WIND SPEEDS OCCURRING IN THE
NEXT FEW HOURS...WITH SLACKENING GRADIENT ALLOWING SOME DECREASES TO
OCCUR THROUGH THE DAY. THOUGH SURFACE OBS HAVE BEEN REPORTING
VISIBILITIES GENERALLY OVER ONE MILE...LOCAL LAW ENFORCEMENT
INDICATES MUCH LOWER LEVELS WHERE THE HEAVY SNOW HAS FALLEN. WILL
CONTINUE WITH BLIZZARD WARNING AND WINTER STORM WARNING THROUGH THE
REST OF THE NIGHT...THOUGH MAY TRANSITION TO A WINTER WEATHER
ADVISORY FOR MUCH OF THE AREA FOR THE MORNING HOURS AS DRIFTING AND
COLD WIND CHILLS PERSIST PENDING THE WIND TRENDS. LOW LEVELS REMAIN
RATHER MOIST WITH DRYING TAKING PLACE FROM SOUTHWEST TO NORTHEAST
THROUGH MID AFTERNOON. EXPECT SOME FLURRIES TO PERSIST IN THE
SATURATED SNOW GROWTH LAYER THROUGH MUCH OF THE MORNING. MAX TEMPS
OF THE DAY MAY OCCUR JUST AFTER SUNSET IN MANY AREAS WITH COLD AIR
ADVECTION THROUGH THE EARLY AFTERNOON.
MODELS VARYING GREATLY WITH LOW TEMP PROGS FOR TONIGHT. HAVE LITTLE
DOUBT THAT TEMPS WILL FALL BELOW ZERO IN DEEP SNOW AREAS WITH LIGHT
WINDS AND LITTLE CLOUD...BUT NAM APPEARS A BIT OVERDONE WITH 925MB
WINDS REMAINING IN THE 20KT RANGE AND FACTORING IN CURRENT TEMPS IN
WESTERN NEBRASKA. DESPITE THE LIGHT WINDS...WIND CHILL VALUES WILL
AGAIN DIP INTO ADVISORY RANGE...BUT WILL LET LATER SHIFTS FINE TUNE
THE LOCATION AND TIMING.
SLOW WARMING TREND IN ORDER FOR THE END OF THE WEEK. LIGHT WINDS
AGAIN EXPECTED THURSDAY NIGHT BUT WEAK WARM AIR ADVECTION AND SOME
CIRRUS SHOULD KEEP TEMPS ABOVE ZERO. NOT SEEING MUCH MOISTURE RETURN
TO SUPPORT PRECIP CHANCES DESPITE PERSISTENT ISENTROPIC LIFT...AND
REMOVED SMALL POPS IN THE SOUTHEAST.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL
NOON WEDNESDAY FOR PORTIONS OF NORTHEAST AND NORTH CENTRAL KANSAS
KSZ008-KSZ009-KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-
KSZ024-KSZ034-KSZ035-KSZ036.
&&
$$
