FXUS63 KTOP 242146
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
346 PM CST THU DEC 24 2009
.DISCUSSION...
THE UPPER LOW WAS LOCATED ACROSS NORTHEAST TEXAS AND WAS BEGINNING
TO LIFT NORTHEAST TOWARDS SOUTHWEST AR. BROAD DEFORMATION ZONE WEST
AND NORTH OF THE UPPER LOW EXTENDED FROM WESTERN OK NORTHEAST ACROSS
THE TOP CWA. MID AND LOW-LEVEL FRONTOGENETICAL FORCING WITHIN THE
TROUGH OF WARM AIR ALOFT WILL PROVIDE SUFFICIENT LIFT AND WRAP
AROUND MOISTURE FOR HEAVY SNOW TO CONTINUE ACROSS THE EASTERN CWA
THROUGH 1200 MIDNIGHT. EVENTUALLY THE UPPER LOW IS FORETASTED TO
LIFT NORTHWARD THROUGH CENTRAL MO INTO SOUTHWEST IA. THIS SHOULD
CAUSE THE HEAVIER SNOW BAND TO LIFT NORTHEAST INTO IA. THE MAJOR
PROBLEM TONIGHT WILL BE THE TIGHT PRESSURE GRADIENT DEVELOPING
BETWEEN A DEEPENING LOW PRESSURE IN SOUTHWEST AR THAT WILL DEEPEN
THROUGH THE NIGHT AS IT HEADS NORTHEAST INTO THE TN RIVER VALLEY.
THE TIGHT PRESSURE GRADIENT ACROSS EASTERN KS WILL CAUSE NORTHWEST
SFC WINDS TO INCREASE TO 35 TO 40 MPH WITH GUSTS OF 45 TO 50 MPH
THROUGH THE NIGHT AND INTO FRIDAY AFTERNOON. THE STRONG WINDS WILL
CAUSE BLIZZARD CONDITIONS TO DEVELOP ALONG AND EAST OF A MARYSVILLE
TO ABILENE LINE. 6 TO 10 INCHES OF SNOW WILL BE POSSIBLE ACROSS THE
EASTERN HALF OF THE CWA WITH ONLY 1 TO 3 INCHES ACROSS THE NORTH
CENTRAL COUNTIES. DRIVING WILL BECOME EXTREMELY DIFFICULT WITH THE
BLOWING AND DRIFTING SNOW. BLIZZARD CONDITIONS EXTENDED FROM CENTRAL
AND WESTERN OK...NORTHWARD UP THE KS TURNPIKE TO EMP. THE BLIZZARD
CONDITIONS WILL SLOWLY EXPAND EAST ACROSS THE EASTERN COUNTIES OF
THE CWA THROUGH THE EARLY EVENING HOURS. THE SNOW WILL GRADUALLY
DECREASE ON FRIDAY BUT STRONG WINDS WILL CONTINUE FOR MUCH OF THE
DAY FRIDAY WITH BLOWING AND DRIFTING SNOW. ATTM...THE HEAVIEST
SNOWFALL MAY OCCUR 20 MILES EITHER SIDE OF THE LINE FROM EMPORIA TO
SENECA. THERE COULD BE SOME ISOLATED AREAS THAT RECEIVE OVER 10
INCHES OF SNOWFALL. MOST AREAS ALONG AND EAST OF A MARYSVILLE TO
HERINGTON LINE WILL SEE 5 TO 10 INCHES OF SNOW. MUCH LOWER AMOUNTS
OF ONE TO THREE INCHES ACROSS NORTH CENTRAL KANSAS OVER
REPUBLIC...CLOUD AND OTTAWA COUNTIES..
GARGAN
LIGHT SNOW WILL CONTINUE TO WRAP AROUND INTENSE UPPER TROUGH AS
IT SLOWLY WOBBLES EASTWARD INTO THE GREAT LAKES REGION FRIDAY
NIGHT INTO THE WEEKEND. AS THE SYSTEM SLOWLY PULLS AWAY SNOW
CHANCES WILL SLOWLY TAPER OFF ACROSS THE CWA FROM SOUTHWEST TO
NORTHEAST AS THE SYSTEM PULLS EASTWARD. ADDITIONAL SNOW AMOUNTS
ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY WILL GENERALLY RANGE
FROM NEAR 2 INCHES IN THE FAR NORTHEAST CORNER NEAR THE NEBRASKA
BORDER TO LESS THAN AN INCH SOUTH OF I 70 AS WINDS GRADUALLY
DECREASE. WARMER AIR ACTUALLY WRAPS AROUND THE SYSTEM SO WITH
CLOUDS AND SOME WIND WILL HELP TO KEEP LOWS AND HIGHS NOT QUITE AS
COLD AS EARLIER MODEL RUNS. STILL SHOULD SEE LOWS IN THE TEENS AND
HIGHS IN THE 20S THROUGH THE WEEKEND. HOWEVER...WINDCHILLS BOTH
FRIDAY AND SATURDAY NIGHTS WILL STILL COMMONLY BE IN THE ZERO TO
10 BELOW RANGE.
A BREAK IN THE PRECIP CHANCES WILL PERSIST INTO EARLY NEXT WEEK
BEFORE THE NEXT WAVE APPROACHES FROM THE DESERT SOUTHWEST. MODELS
ARE IN AGREEMENT THAT THE AREA MAY GET CLIPPED BY THIS WAVE AS ITS
MOVES THROUGH BY MIDWEEK. THEREFORE ADDED A SLIGHT CHANCE FOR LIGHT
SNOW AT THAT TIME. TEMPERATURES WILL REMAIN BELOW NORMAL WITH HIGHS
IN THE UPPER 20S TO LOWER 30S. 63
&&
.AVIATION...
DEFORMATION ZONE SETTING UP ON THE NORTHWEST PERIPHERY OF
INTENSE UPPER LOW NOW APPROACHING FROM THE SOUTH. IT WILL SET
UP IN CLOSE PROXIMITY TO THE TAF SITES THROUGH THE AFTERNOON/EVENING
HOURS...ALTHOUGH EXPECTED TO BE CLOSER TO KFOE/KTOP SITES THAN
KMHK. THIS PRODUCE LIGHT/MODERATE SNOW BAND (SOME SLEET THROUGH
19Z) ACROSS THE TAF SITES...ESPECIALLY THIS EVENING WITH
LIFR/VLIFR VSBYS IN SNOW AND BLOWING SNOW UNTIL AROUND 07-09Z
TIMEFRAME...BUT THE STRONG WINDS WILL PERSIST TONIGHT/FRIDAY
WITH MORE BLOWING SNOW BUT WITH SLOW IMPROVEMENT IN CIGS TO AROUND
1000 FEET BY THE END OF THE FCST.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...BLIZZARD WARNING UNTIL 6 PM FRIDAY FOR
KSZ010-KSZ011-KSZ012-KSZ022-KSZ023-KSZ024-KSZ026-KSZ036-KSZ037-KSZ038-KSZ039-
KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.
WINTER STORM WARNING UNTIL 6 PM FRIDAY FOR KSZ009-KSZ021-KSZ035.
WINTER WEATHER ADVISORY UNTIL 6 PM FRIDAY FOR KSZ008-KSZ020-
KSZ034.
&&
$$
63
