FXUS63 KTOP 241324
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
724 AM CST THU DEC 24 2009
.UPDATE...
UPDATED FOR 12Z AVIATION.
&&
.DISCUSSION...
SEE PREVIOUS DISCUSSION.
&&
.AVIATION...
MAINLY IFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS. BRIEF
WINDOW OF FZRA AND PL BEFORE TRANSITION TO ALL SNOW BY MIDDAY.
WINDS WILL SIGNIFICANTLY INCREASE LATER TODAY WITH BLOWING SNOW
AND REDUCED VISBY. SNOW WILL CONTINUE THROUGH THE END OF THE TAF
PERIOD. BLAIR
&&
.PREV DISCUSSION... /ISSUED 419 AM CST THU DEC 24 2009/
..SIGNIFICANT WINTER STORM TO AFFECT THE AREA TODAY THROUGH
CHRISTMAS...
DISCUSSION...H5 NORTHERN AND SOUTHERN STREAM SYSTEMS VERY
APPARENT ON WV LOOP. A FEW SCT SHRA WERE MAINLY EAST OF US 75. A
SECOND AREA OF PRECIP WAS MOVING NORTH THROUGH OKLAHOMA.
MODEL TRENDS CONTINUE TO MOVE THE H5 LOW AND ASSOCIATED SFC LOW EVER
SO SLIGHTLY TO THE EAST WHICH PULLS THE MAIN HEAVY SNOW AXIS TO THE
EAST AS WELL. THE GFS/ECMWF ARE CLOSER TOGETHER THAN THE NAM WHICH
PULLS THE SYSTEM THE FARTHEST TO THE EAST SO WILL LEAN MORE ON THE
GFS/ECMWF.
EARLY TODAY...AS MULTIPLE SHWVS MOVE ACROSS THE CWA EARLY THIS
MORNING THERE WILL BE ENOUGH DYNAMIC COOLING TO ALLOW FOR SOME
FREEZING RAIN AND SLEET TO MIX WITH RAIN EARLY ON. HOWEVER...SINCE
THE SYSTEM IS SO STRONG IT WONT TAKE LONG BEFORE ANY MIXED PRECIP
CHANGES COMPLETELY TO SNOW. HAVE KEPT A MIX OVER THE WARNING AREA
EARLY ON BEFORE TRANSITIONING TO ALL SNOW NO LATER THAN THIS
AFTERNOON.
H5 NORTHERN AND SOUTHERN STREAM SYSTEMS WILL PHASE SOMETIME LATE
TONIGHT INTO FRIDAY MORNING. THE RESULTANT SFC LOW WILL DEEPEN AS
IT MOVES INTO ARKANSAS LATER TONIGHT WITH THE MOST SIGNIFICANT
DEEPENING OCCURRING THIS EVENING TO LATE TONIGHT. AT THIS TIME IT
LOOKS LIKE THE HEAVIER SNOW WILL FALL BETWEEN TONIGHT AND FRIDAY
MORNING AS THE MORE SIGNIFICANT ENERGY MOVES THROUGH...THE SYSTEM
BECOMES NEGATIVELY TILTED AND RAPID PRESSURE FALLS OCCUR. WITH THE
TRACK FARTHER TO THE EAST...FEEL THAT OUR WESTERN CWA WILL NOT SEE
MUCH SNOW OUT OF THIS...MAYBE ONE TO TWO INCHES. THAT SAID HAVE
DOWNGRADED THE WARNING IN THAT AREA TO A WINTER STORM ADVISORY.
FARTHER EAST...WITH THE AREA OF HEAVY SNOW REMAINING IN THE SAME
PLACE ALTHOUGH WITH SOMEWHAT LESSER AMOUNTS HAVE CONTINUED WITH THE
WS WARNING WITH STORM TOTAL 5 TO 7 INCHES ANTICIPATED. IN ADDITION
TO WHATEVER SNOW FALLS...SUSTAINED WIND 25 TO 35 MPH WILL CREATE
TRAVEL HAZARDS AS SNOW BLOWS AROUND OVER ROADWAYS. AS WIND
CONTINUES TO BE STRONG ON CHRISTMAS DAY...WIND CHILLS RANGING FROM 5
TO 15 BELOW WILL BE POSSIBLE THROUGH THE DAY ON CHRISTMAS.
AS THE H5 LOW SITS OVER IOWA FRIDAY NIGHT INTO SATURDAY THERE IS
STILL A CHANCE FOR SNOW OVER MOSTLY THE NORTHERN HALF OF THE CWA.
HAVE GRADUALLY TAPERED OFF SNOW BY SATURDAY EVENING.
SUNDAY/MONDAY...DRY CONDITIONS EXPECTED FOR NOW BUT COLD TEMPS WILL
LINGER. MOST AREAS WILL NOT GET OUT OF THE 20S EITHER DAY BUT WILL
WARM TO NEAR FREEZING BY TUES/WED.
SALLY
&&
.TOP WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING UNTIL 6 PM FRIDAY FOR KSZ010-KSZ011-KSZ012-
KSZ023-KSZ024-KSZ026-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-
KSZ058-KSZ059.
WINTER WEATHER ADVISORY UNTIL 6 PM FRIDAY FOR KSZ008-KSZ009-
KSZ020-KSZ021-KSZ022-KSZ034-KSZ035-KSZ036-KSZ037.
&&
$$
