FXUS63 KMPX 091816
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1216 PM CST WED DEC 9 2009
.UPDATE...
AS PRIMARY WIND SURGE HAS PASSED AND BLOWING SNOW VISIBILITIES
SHOULD GRADUALLY IMPROVE...THE THOUGHTS ARE TO REPLACE A LARGE
PORTION OF THE BLIZZARD WARNING WITH A WINTER WEATHER ADVISORY FOR
CONTINUED BLOWING SNOW INTO THE EVENING. WITH THE IMPROVEMENT
SEEN...WE EXPECT TO BE ABLE TO DO THIS IN THE MID-AFTERNOON. WILL
CONTINUE TO CHECK WITH LAW ENFORCEMENT THROUGHOUT THE CWA AS TO
CONDITIONS IN THEIR COUNTIES.
.DISCUSSION...
MAIN FORECAST CONCERNS (SHORT TERM) ARE ASSOCIATED WITH SFC WINDS
AND HOW STRONG THEY WILL DEVELOP THIS MORNING...AND IF BLIZZARD
CONDITIONS ARE MET.
SEVERAL MESOSCALE FEATURES ARE NOTED ON REGIONAL RADAR AND
SATELLITE IMAGES EARLY THIS MORNING THAT HAS DEPICTED AN ENHANCED
AREA OF LIFT AND THUS INCREASED REFLECTIVITY OF SN/+SN. SFC WINDS
HAVE STARTED TO INCREASE SLOWLY FROM EARLIER THIS EVENING...WITH
SEVERAL AWOS/ASOS'S IN THE FAR WEST REPORTING GUSTS OF 35 TO 45
MPH. HOWEVER...DUE TO LIMITED SNOWFALL IN THESE AREAS...VSBYS HAVE
BEEN 1/2SM OR HIGHER. MOST AREAS HAVE BEEN AVERAGING BETWEEN 1 &
2SM. STILL...LATEST 13KM RUC CONTINUES THE TREND OF INCREASING
WINDS OVERNIGHT WITH SUSTAINED WINDS OF 30 TO 40 MPH...AND NEAR
50 MPH IN OPEN COUNTRY WHERE THE CURRENT BLIZZARD WARNING IS IN
EFFECT BETWEEN 09/15Z.
AS FOR SNOWFALL AND ACCUMULATIONS FOR THE NEXT 12/18 HRS...HAVE
BASICALLY FOLLOWED THE RICH COLUMN OF OMEGAS/MOISTURE WHICH IS
MAXIMIZED BETWEEN 92H/60H...AND IS SHOWING THE BEST CONTINUED
SNOWFALL ALONG A LINE FROM RICE LAKE WISCONSIN...TO
HASTINGS/ALBERT LEA MINNESOTA THROUGH 18Z. THIS IS WHERE THE BEST
POTENTIAL OF 8 TO 12 INCHES WILL EXIST BEFORE TAPERING OFF TO
FLURRIES THIS AFTERNOON. SEVERAL COUNTIES IN WEST-CENTRAL
WISCONSIN WILL ALSO BE CLOSE TO 10-12" BEFORE IT TAPERS OFF LATER
TODAY...BUT THIS WILL LIKELY BE ASSOCIATED WITH ANOTHER SHORT WAVE
ACROSS SOUTHERN IOWA EARLY THIS MORNING. THE MEAN 50H SHORT WAVE
ACROSS THE EASTERN DAKOTAS WILL LIKELY BE THE MAIN PLAYER FOR
ENDING THE -SN OR AT LEAST THE ACCUMULATING SNOWFALL LATER TODAY.
THIS AXIS WILL BE NEAR THE MN/SD/ND BORDER BY 12Z...THEN SLOWLY
MOVING INTO WESTERN WISCONSIN BY 00Z. THERE MAY BE SOME LINGERING
-SN WITH MINOR ACCUMULATIONS ACROSS RICE LAKE/LADYSMITH AREA
DURING THE EVENING...BUT MOST AREAS SHOULD SEE THE END OF
MEASURABLE PRECIPITATION BY LATER THIS AFTN.
AS FOR WINDS...THE STRONGEST AND MOST EFFECTIVE IN TERMS OF
PRODUCING BLIZZARD OR NEAR BLIZZARD CONDITIONS WILL BE FROM 09Z TO
18Z TODAY. WINDS SHOULD SLOWLY DECREASE THIS AFTN AS THE MAIN SFC
LOW MOVES EAST INTO THE EASTERN GREAT LAKES REGION.
AFTER THIS EVENING...A QUIET WEATHER PATTERN SHOULD DEVELOP AS THE
EXITING STORM TODAY WILL BE ACROSS SOUTHEASTERN CANADA...WITH A
SIGNIFICANT LONG WAVE TROUGH (NW TO SE ACROSS SOUTHERN
CANADA...INTO THE NE U.S.) BEGINS TO CONTROL THE WEATHER PATTERN
ACROSS THE UPPER MIDWEST. ALTHOUGH CURRENT ENSEMBLE MEMBERS AND
THE GENERAL MEAN OF THE ARCTIC BOUNDARY WILL BE CLOSE TO THE
AREA...I DON'T THINK ANY TYPE OF SUBSTANTIAL WARM-UP IS
ANTICIPATED IN OUR AREA UNTIL THIS PATTERN CHANGES...OR UNTIL A
STORM SYSTEM ACROSS THE ROCKIES BY EARLY NEXT WEEK...BEGINS TO
BUCKLE THIS LONG WAVE TROUGH AND ALLOW FOR MODIFIED PACIFIC AIR TO
FILTER INTO OUR REGION. THEREFORE...TOO MANY UNCERTAINTIES IN THE
EXTENDED PERIOD TO CHANGE. ..JLT..
&&
.AVIATION.../18Z TAF ISSUANCE/
DEEP CYCLONIC FLOW ENTRENCHED OVER THE AREA WITH GUSTY WINDS AND
BLOWING SNOW. FALLING SNOW IS PRIMARILY IN WESTERN WI AND THAT
WILL GRADUALLY WANE THROUGH THIS AFTN AND EARLY EVE. THE BLOWING
SNOW HAS REDUCED VISIBILITIES TO THEIR LOWEST IN SOUTH CENTRAL
MINNESOTA...WHERE UNDER ONE HALF MILE HAS BEEN COMMON. IFR VISBYS
HAVE BEEN TYPICAL FROM KRWF TOWARDS KMSP AND INTO WRN WI. THINK
THESE WILL ALL ONLY GRADUALLY IMPROVE AS WINDS REMAIN NEARLY
STEADY THROUGH 21Z. THEN AS THE WINDS BEGIN DROPPING THE
VISIBILITIES SHOULD IMPROVE SOMEWHAT MARKEDLY...PRIMARILY AFTER
DARK. THE WINDS MAY STILL GUST AS HIGH AS 30 KTS AT TAF SITES
OUTSIDE OF KAXN AND KSTC. CIGS WILL BE MAINLY MVFR THROUGH 22Z AS
COLD AIR ADVECTION STRATOCU CLOUDS PREVAIL. THESE WILL THEN
QUICKLY LIFT AND SCATTER AS THE CENTER OF THE MAIN SYSTEM DEPARTS
EASTWARD OVER THE GREAT LAKES. BEHIND THIS SYSTEM...WINDS WILL
GRADUALLY BACK TO THE W LATE TONIGHT AND WSW THU MORNING. SOME
COLD AIR ADVECTION STRATOCU IS EXPECTED DURING THE DAY THU.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 10 AM CST THURSDAY
FOR BLUE EARTH-BROWN-CARVER-FARIBAULT-FREEBORN-KANDIYOHI-LE
SUEUR-MARTIN-MCLEOD-MEEKER-NICOLLET-REDWOOD-RENVILLE-RICE-
SCOTT-SIBLEY-STEELE-WASECA-WATONWAN.
BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR BLUE EARTH-BROWN-
CARVER-DAKOTA-FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-MARTIN-
MCLEOD-NICOLLET-RICE-SCOTT-SIBLEY-STEELE-WASECA-WATONWAN.
WIND CHILL ADVISORY UNTIL 10 AM CST THURSDAY FOR CHIPPEWA-
DOUGLAS-LAC QUI PARLE-POPE-STEVENS-SWIFT-TODD-YELLOW
MEDICINE.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR BENTON-
KANABEC-KANDIYOHI-MEEKER-MILLE LACS-MORRISON-STEARNS.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-
CHISAGO-HENNEPIN-ISANTI-RAMSEY-SHERBURNE-WASHINGTON-WRIGHT.
BLIZZARD WARNING UNTIL 6 PM CST THIS EVENING FOR REDWOOD-
RENVILLE.
WI...BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR CHIPPEWA-DUNN-
EAU CLAIRE-PEPIN-PIERCE.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-POLK-
RUSK-ST. CROIX.
&&
$$
JLT/MTF
