FXUS63 KTOP 261116
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
516 AM CST SAT DEC 26 2009
.UPDATE...
UPDATED THE AVIATION DISCUSSION FOR THE 12Z TAFS.
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.DISCUSSION...
SEE PREV DISCUSSION.
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.AVIATION...
LATEST WAVE ROTATING AROUND THE UPPER LOW IS BRINGING IN SOME
HEAVIER BANDS OF SNOW. ISENTROPIC SFCS SHOW LIFT ROTATING TO THE
EAST OF THE TERMINALS BEFORE NOON. OBS UPSTREAM DO NOT SHOW AN
EXPANSIVE DECK OF LOW CLOUDS. THEREFORE WILL BRING SOME MVFR CIGS
WITH TEMPO IFR VSBY WITH THE SNOW BANDS...AND GENERALLY GO ON THE
OPTIMISTIC SIDE WITH VFR CONDITIONS ONCE THE FORCING ROTATES EAST.
WOLTERS
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.PREV DISCUSSION.../334 AM CST SAT DEC 26 2009/
MAIN THEME IN SHORT TERM IS GRADUALLY IMPROVING CONDITIONS OVER THE
NEXT 24 HOURS ACROSS THE CWA. AS OF EARLY THIS MORNING...CENTER OF
LARGE UPPER LOW WAS LOCATED OVER NORTHERN ILLINOIS. EMBEDDED VORT
MAXES ALONG THE BROAD CIRCULATION WAS AIDING IN ENHANCING VERTICAL
ASCENT OVER PORTIONS OF NEBRASKA AND KANSAS...WITH SCATTERED AREAS
OF LIGHT TO OCCASIONALLY MODERATE SNOW. 24 HOUR WATER VAPOR IMAGERY
LOOP SHOWS A DECREASING ORGANIZATIONAL PRESENTATION OF WARM CONVEYOR
BELT ALOFT AS AXIS OF DEEPER MOISTURE CONTINUES TO SHIFT WELL TO THE
EAST OF THE UPPER LOW OVER THE EASTERN SHORES OF THE ATLANTIC. THE
UPPER LOW WILL WOBBLE AROUND THE WESTERN GREAT LAKES STATES TODAY AS
THE SURFACE LOW CURRENTLY LOCATED NEAR THE MO/IA BORDER SLOWLY MOVES
NORTHEASTWARD. THE SFC LOW WILL BEGIN TO FILL TODAY WITH A GRADUALLY
DECREASING PRESSURE GRADIENT OVER THE AREA. WINDS WILL BE A LITTLE
WEAKER TODAY...WITH NORTHWEST WINDS AVERAGING AROUND 20 TO 25 MPH
WITH GUSTS UP TO 30 MPH. LIGHT TO OCCASIONALLY BRIEF PERIODS OF
MODERATE SNOW WILL CONTINUE TODAY. NEW SNOWFALL ACCUMULATION THROUGH
TONIGHT WILL RANGE FROM ONE HALF OF AN INCH OR LESS SOUTH OF
INTERSTATE 70...WITH ONE HALF OF AN INCH TO ONE INCH NORTH OF
INTERSTATE 70. WOULD STILL EXPECT TO SEE SOME DRIFTING OF SNOW IN
LOCALIZED AREAS ALTHOUGH NOT NEARLY AS WIDESPREAD AND THE MAGNITUDE
THAT WAS PREVIOUSLY EXPERIENCED OVER THE PAST 36 HOURS. WITH WINDS
ON A GRADUAL DECREASING TREND AND NEW SNOWFALL ACCUMULATIONS OF ONE
INCH OR LESS...EXPECT GREATEST IMPACT OF BLOWING/DRIFTING SNOW TO
HAVE PASSED. THEREFORE...WILL EXPIRE WINTER WX ADVISORY THIS MORNING
AND CONTINUE TO MENTION AREAS OF BLOWING SNOW IN FORECAST.
TONIGHT/SUNDAY/BEYOND...INFLUENCE OF UPPER LOW WILL CONTINUE TO
LESSEN. CONTINUED CHANCES OF LIGHT SNOW OR FLURRIES ACROSS THE AREA
TONIGHT WITH MEASURABLE PRECIPITATION CHANCES OVER BY SUNRISE
SUNDAY. LOW CLOUDS WILL FINALLY DEPART THE REGION SUNDAY NIGHT.
UPPER LEVEL RIDGING WILL TAKE SHAPE ACROSS THE CENTRAL PLAINS MONDAY
INTO TUESDAY IN ADVANCE OF THE NEXT UPPER LEVEL SYSTEM...SPELLING
DRY/TRANQUIL WEATHER.
NO BIG CHANGE MADE TO TEMPERATURES. WITH WIND...SNOW COVER...AND
OVERCAST CONDITIONS TODAY INTO SUNDAY...SMALL DIURNAL CURVE IN
TEMPERATURES EXPECTED WITH LOWS IN THE TEENS AND HIGHS IN THE 20S.
AS HIGH PRESSURE MOVES INTO THE REGION AND CLOUDS CLEAR...COLDER
MINIMUM READINGS CAN BE ANTICIPATED SUNDAY NIGHT AND MONDAY NIGHT.
LOWS SHOULD FALL INTO THE SINGLE DIGITS TO LOWER TEENS.
NEXT CHANCE FOR SNOW STILL ON TRACK FOR TUESDAY NIGHT INTO
WEDNESDAY...ALTHOUGH BEST DYNAMICS/MOISTURE WELL TO THE SOUTH OF THE
REGION. NO CHANGES MADE BEYOND TUESDAY.
BLAIR
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.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
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