National Weather Service Raw Text Product

156 
FXUS63 KTOP 062337
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
537 PM CST MON FEB 6 2012

...UPDATE TO AVIATION...

.DISCUSSION...

SHORT TERM (THROUGH TUESDAY NIGHT)...

SUNNY SKIES AND A SOUTHWEST BREEZE HAVE DOMINATED THE AREA TODAY 
WITH TEMPERATURES WARMING NICELY...INTO THE LOWER 50S ACROSS MUCH OF 
THE AREA WITH UPPER 40S CLOSER TO THE SNOWPACK NEAR THE NEBRASKA 
BORDER. WIDESPREAD PRESSURE FALLS WERE OVERSPREADING THE CENTRAL 
PLAINS WITH A LEE SURFACE LOW CENTERED OVER SOUTHEAST COLORADO. 
ALOFT...A CUT OFF UPPER LOW WAS CENTERED OVER WESTERN COLORADO WITH 
A JET STREAK ACROSS NORTHERN NEW MEXICO AND MAKING ITS WAY TOWARD 
KANSAS. THE UPPER LOW WAS IN THE PROCESS OF BEING ABSORBED INTO A 
STRONG NORTHERN STREAM SHORT WAVE TROUGH ENTERING THE GREAT LAKES 
REGION. THE END RESULT WILL BE THE WAVE OVER COLORADO WEAKENING... 
BECOMING POSITIVELY TILTED...AND EJECTING EAST ACROSS THE CENTRAL 
PLAINS TONIGHT THROUGH TUESDAY. 

OVERNIGHT LOWS WILL BE ON THE WARM SIDE AS MID TO HIGH LEVEL CLOUDS 
OVERSPREAD THE AREA AFTER A PARTICULARLY WARM AFTERNOON. THE MAIN 
PLAYERS IN TERMS OF LOW TEMPS ARE HOW SOON THE CLOUDS MOVE IN...AND 
A COLD FRONT ENTERING THE AREA JUST BEFORE SUNRISE. CURRENTLY FEEL 
THAT MID 20S ARE APPROPRIATE IN THE NORTHWESTERN FORECAST AREA WITH 
MID 30S IN THE SOUTHEASTERN THIRD. HIGHS ON TUESDAY WILL ALSO DEPEND 
LARGELY ON FRONTAL TIMING WITH VERY LITTLE TEMP RISE IN THE 
NORTHWEST WHILE THE SOUTHEAST MAY CLIMB INTO THE MID 40S BEFORE 
FALLING. COLD ADVECTION FILLS IN BEHIND THE SYSTEM WITH WED MORNING 
LOWS IN THE TEENS AND 20S...WITH THE GRADIENT DEPENDENT UPON HOW 
FAST CLOUD COVER EXITS.

VERTICAL ASCENT WILL ALSO BE ON THE INCREASE FROM WEST TO EAST AFTER 
MIDNIGHT. A BAND OF ISENTROPIC ASCENT WILL PRECEDE THE COLD FRONT 
AND SHOULD ENCOURAGE SOME GRADUAL SATURATION ALOFT...BUT THERE WILL 
BE PLENTY OF DRY AIR TO OVERCOME. SO WHILE SOME MODEL GUIDANCE 
SUGGESTS AN AREA OF PRECIP DEVELOPING ACROSS EASTERN KANSAS AFTER 
MIDNIGHT AND LASTING INTO THE MORNING HOURS...FEEL THAT THIS WILL 
MOSTLY BE IN THE FORM OF VIRGA...SPRINKLES...OR FLURRIES. HAVE STILL 
INCLUDED AT LEAST SLIGHT CHANCES FOR THE POTENTIAL OF A PERSISTENT 
ZONE OF LIFT TO OVERCOME THE DRY AIR. THE MORE ORGANIZED AREA OF 
LIGHT PRECIP WILL BEGIN OVER CENTRAL KANSAS BY MID MORNING AND MOVE 
EAST ALONG WITH THE UPPER LEVEL WAVE. SHOULD SEE MAINLY SNOW IN 
NORTH CENTRAL KANSAS...WITH SOME RAIN POTENTIALLY MIXING IN TO THE 
SOUTH AND EAST BEFORE CHANGING OVER TO LIGHT SNOW. PRECIP TOTALS 
SHOULD STILL BE LIGHT...AND WITH GROUND TEMPS ACROSS MUCH OF THE 
AREA STILL IN THE UPPER 30S TO AROUND 40 DO NOT EXPECT MUCH IN THE 
WAY OF SNOW ACCUMULATION. WITH THAT SAID...A FEW AREAS COULD 
APPROACH A HALF INCH OF SNOW. 

BARJENBRUCH

MID RANGE AND EXTENDED FORECAST (WEDNESDAY THROUGH MONDAY)...

PATTERN FOR THE MID RANGE AND EXTENDED FORECAST LOOKS TO BE 
CHILLY...BUT NOT MUCH PRECIPITATION IS EXPECTED...AT LEAST THROUGH 
THE END OF THE WEEK AND INTO THE WEEKEND. THE MID TO LATE PART OF 
THE WEEK LOOKS TO BRING BELOW CLIMATOLOGICAL NORMAL TEMPERATURES AS 
THE UPPER LOW WHICH WILL BRING PRECIP ON TUESDAY/WEDNESDAY MOVES 
TO THE EAST. UPPER LEVEL SUBSIDENCE MOVES IN BEHIND THE WAVE CAUSING
SKIES TO CLEAR OUT. SURFACE RIDGE ALSO MOVES IN LATE WEDNESDAY
WHICH WILL CAUSE WINDS AT THE SURFACE TO BECOME CALM. THE
COMBINATION OF CLEAR SKIES AND CALM WINDS WILL BRING COLD
CONDITIONS ON THURSDAY MORNING. LEANED TOWARD THE LOWER END OF
ENSEMBLE GUIDANCE REGARDING THURSDAY MORNING LOWS...AND INPUT A
FORECAST WHICH REFLECTS UPPER SINGLE DIGITS IN FAR NORTHEASTERN
KANSAS AND LOWER TO MID TEENS FURTHER SOUTH ALONG INTERSTATE 70
FOR THURSDAY MORNING. WITH LIGHT NORTHERLY WINDS AND A COLD AIR MASS
OVER THE AREA...EXPECT HIGHS ON THURSDAY TO REMAIN BELOW SEASONAL
NORMALS...AND EXPECT COOL CONDITIONS TO PERSIST THROUGH THE END
OF THE WEEK BEFORE SOUTHERLY FLOW FINALLY RETURNS TO THE AREA FOR
THE END OF THE WEEKEND. BOTH ECMWF AND GFS HINT AT SOME SLIGHT
CHANCE POPS FOR BEGINNING OF NEXT WEEK AS A SHORTWAVE TROUGH
PUSHES THROUGH THE AREA. WITH SOME DISAGREEMENT BETWEEN THE ECMWF
AND THE GFS REGARDING PRECIP TYPE WEATHER TYPE COULD BE RAIN OR
SNOW DEPENDING ON THE DEPTH OF COOL AIR AND MOISTURE IN THE
ATMOSPHERIC COLUMN. WILL NEED TO KEEP AN EYE ON THE LOWER
ATMOSPHERIC TEMPERATURE TRENDS AND ADJUST AS NECESSARY.

JL

&&

.AVIATION...

MAIN CONCERN IS CEILING HEIGHTS IN THE LAST HALF OF THE FORECAST.
STRATUS IN THE DAKOTAS WILL SURGE SOUTH WITH A COLD FRONT
TONIGHT...WITH THESE FEATURES PASSING IN THE 13-16Z TIME FRAME.
WILL KEEP MVFR CIGS AT THIS POINT...BUT SOME CONCERN FOR LOWER
LEVELS EXISTS...ESPECIALLY AFTER 20Z. THIS IS WHEN THE BEST
PROBABILITY FOR SOMEWHAT HEAVIER PRECIP WILL OCCUR. KEPT ANY
VISBYS IN SNOW LIMITED TO MVFR FOR NOW. 

65

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$