FXUS63 KTOP 251327
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
727 AM CST FRI DEC 25 2009
.UPDATE...
UPDATED THE FORECAST TO DOWNGRADE THE BLIZZARD WARNING TO AN
ADVISORY.
&&
.DISCUSSION...
THE MAIN DEFORMATION AND BANDS OF MODERATE SNOW CONTINUE TO LIFT
NORTH. AREA OBSERVATIONS SHOW VISIBILITIES SLOWLY IMPROVING. WITH
MODELS SHOWING THE BETTER SNOWFALL RATES REMAINING NORTH THROUGH THE
DAY...EXPECT CONDITIONS TO KEEP A TREND OF GRADUAL IMPROVEMENT.
ADDITIONAL SNOW ACCUMULATIONS WILL ONLY BE AROUND 1 INCH NEAR I-70
TO POSSIBLY AS MUCH AS 3 INCHES OVER FAR NORTHEAST KS. THE WINDS
WILL BE THE BIG PROBLEM THOUGH AS WEST WINDS STAY UP BETWEEN 20 AND
30 MPH. THIS WILL LIKELY KEEP SNOW DRIFTING...HENCE THE ADVISORY.
WOLTERS
&&
.AVIATION...
ANTICIPATE A GRADUAL IMPROVEMENT TO VSBY AND CIGS AS UPPER
DEFORMATION ZONE LIFTS NORTH. STILL THINK THAT MVFR VSBY AND CIGS
AROUND 2 KFT WILL PERSIST THROUGH THE PERIOD ONCE THE HEAVIER SN AND
IFR CONDITIONS LIFT NORTH OF THE TERMINALS. OPTED TO KEEP A MENTION
OF LIGHT SN UNTIL 00Z. NOT SURE THERE WILL BE SN AFTER 00Z SINCE
MODELS INDICATE DEEP VERTICAL MOTION ENDING BY EARLY AFTERNOON. ALL
DEPENDS ON HOW THE LOW WOBBLES OVER IA.
WOLTERS
&&
.PREV DISCUSSION.../308 AM CST FRI DEC 25 2009/
ONGOING SIGNIFICANT WINTER STORM CONTINUES TO BE MAIN FOCUS WITHIN
FORECAST PACKAGE. AS OF EARLY THIS MORNING...THE UPPER LOW WAS
CENTERED ACROSS SOUTHERN MISSOURI WITH THE SFC LOW OVER EAST CENTRAL
MISSOURI. LATE EVENING DEFORMATION BAND REMAINS OVER EASTERN KANSAS
WITH A NEW MORE PRONOUNCED BAND ACROSS WESTERN MISSOURI. SNOWFALL
RATES THIS MORNING HAVE AVERAGED ONE HALF INCH OR LESS PER HOUR.
INITIAL BAND CONTINUES TO SHOW SIGNS OF WEAKENING AS RADAR
REFLECTIVITY RETURNS HAVE TRENDED DOWNWARD AND IR IMAGERY SHOWS
CLOUD TOPS WARMING. EXPECT HEAVIEST ACTIVITY TO BE LOCATED ACROSS
FAR EASTERN AND FAR NORTHEAST PORTIONS OF THE CWA BY SUNRISE. THE
OTHER IMPACT CONTINUES TO BE THE STRONG NORTH-NORTHWEST WINDS OF 20
TO 30 MPH WITH GUSTS IN EXCESS OF 40 MPH. THIS HAS LED TO WIDESPREAD
REDUCED VISIBILITIES WITH AREAS OF BLIZZARD CONDITIONS AND
SIGNIFICANT DRIFTING AND BLOWING OF SNOW...WITH MANY DRIFTS IN
EXCESS OF A FOOT.
AS THE UPPER LOW MOVES INTO SOUTHERN IOWA TODAY...A SECONDARY VORT
MAX WILL DIVE INTO THE REGION AND PHASE WITH THE INITIAL
DISTURBANCE. AS THE SFC LOW OCCLUDES...IT WILL BEGIN MOVING BACK
WESTWARD AND THEN SOUTHWESTWARD INTO SOUTHWEST IOWA BY SUNSET. THE
CONTINUING CLOSE PROXIMITY OF THIS SYSTEM WILL ALLOW FOR ADDITIONAL
LIGHT SNOWFALL OVER THE MAJORITY OF THE CWA. THE HIGHEST PROBABILITY
OF ACCUMULATING SNOWFALL...WHERE OCCASIONALLY MODERATE SNOWS WILL BE
POSSIBLE...WILL BE ACROSS FAR NORTHEAST KANSAS CLOSEST TO THE NEAR
VERTICALLY STACKED SYSTEM. ADDITIONAL SNOWFALL ACCUMULATIONS NOW
THROUGH SATURDAY WILL RANGE FROM ONE INCH OR LESS SOUTH OF
INTERSTATE 70...ONE TO TWO INCHES ALONG INTERSTATE 70 TO HIGHWAY
36...AND TWO TO THREE INCHES NORTH OF HIGHWAY 36. IN ADDITION TO
THE SNOW...GUSTY NORTHERLY WINDS WILL CONTINUE THROUGH SATURDAY.
THIS WILL LIKELY LEAD TO ADDITIONAL BLOWING AND DRIFTING OF NEW
AND ALREADY FALLEN SNOW. WILL CONTINUE WINTER WEATHER HEADLINES AS
IS THIS MORNING FOR THE AFOREMENTIONED HAZARDOUS CONDITIONS.
THE UPPER SYSTEM WILL FINALLY MAKE PROGRESS AWAY FROM THE CWA BY
SATURDAY NIGHT. LIKEWISE...LIGHT SNOW CHANCES WILL END FROM WEST TO
EAST BEGINNING SATURDAY AFTERNOON INTO SATURDAY NIGHT. BY SUNRISE
SUNDAY...EXPECT ALL PRECIPITATION TO BE EAST OF THE REGION.
AS FOR TEMPERATURES...CLOUD COVER...CAA...AND SNOW COVER WILL KEEP
HIGHS TODAY IN THE MIDDLE TEENS TO LOWER 20S. ADDITIONALLY...WIND
CHILL VALUES THIS MORNING AND AGAIN TONIGHT WILL FALL INTO THE ZERO
TO MINUS 10 RANGE. MINIMUM TEMPERATURES THE NEXT COUPLE DAYS WILL
REMAIN IN THE LOWER TO MIDDLE TEENS AS LOW LEVEL CLOUD COVER AND
WIND SPEEDS HELP MITIGATE COLD POTENTIAL WITH FRESH SNOW COVER. NO
CHANGES MADE TO FORECAST BEYOND MONDAY.
BLAIR
&&
.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.
&&
$$
