FXUS63 KMPX 090726
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
126 AM CST WED DEC 9 2009
.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.../06Z TAF ISSUANCE/
MAJOR WINTER STORM CURRENTLY UNFOLDING WILL HAVE SIGNIFICANT
IMPACTS ON ALL TAF SITES FOR AT LEAST FIRST 12 HRS OF TAF. AT
6Z...DEEPENING SFC LOW ANALYZED OVER WRN IL IS PROGGED TO BE NE OF
LAKE HURON BY 06Z WEDNESDAY. CURRENT SATELLITE/RADAR IMAGERY
SHOWING BANDED SNOW OVER SE MN INTO WC WI THAT WILL BE IMPACTING
MSP/RNH/EAU THROUGH AT LEAST 15Z WITH PERIODS OF HEAVIER
SNOWFALL. OTHER IMPACT OF DEEPENING LOW IS RAPIDLY INCREASING
WINDS. THESE WINDS WILL BE SLOWLY TURNING TO THE NW WITH
TIME...WITH NAM/BUFKIT PROFILES SUGGESTING GUST POTENTIAL
APPROACHING 40 KTS AT ALL TERMINALS THROUGH THE MORNING...WITH
GUSTS OVER 30KTS WELL INTO THE AFTERNOON...WHICH WILL KEEP VSBYS
REDUCED THROUGH THE AFTERNOON.
AXN/RWF/STC...THESE TERMINALS WILL SEE THE LEAST AMOUNT OF
SNOWFALL AS BEST FGEN FORCING WILL BE CENTERED OFF TO THE EAST. IN
ADDITION...EXPECT MAINLY MVFR CIGS TO PERSIST OUT HERE...AS SEEN
IN THE GFSLAMP...AS BETTER MOISTURE AND LOWER CLOUDS WILL STAY
CLOSER TO THE LOW...THOUGH A FEW MOMENTS DOWN IN IFR CATEGORY CAN
NOT BE RULED OUT THROUGH 15Z. THOUGH SNOWFALL WILL NOT BE AS
MUCH...STILL PLENTY OF WINDS TO CREATE BLSN ISSUES OUT TO ABOUT
21Z BEFORE WINDS BEGIN TO DIE DOWN.
MSP...LOOKS LIKE WILL BE ON WRN EDGE OF HEAVIEST BANDED SNOW
THROUGH THE EVENING...AND WITH WINDS...EXPECT VSBY TO DROP INTO
THE 1/2SM RANGE FOR A GOOD PORTION OF THE MORNING RUSH...ALSO CAN
NOT RULE OUT SOME VSBYS SNEAKING DOWN UNDER 1/4SM. GFSLAMP HOLDS
VSBYS DOWN TO IFR THROUGH THE AFTERNOON...AND WITH WINDS EXPECTED
TO BE AS HIGH AS THEY ARE THIS SEEMS VERY PLAUSIBLE. GFS ALSO
HOLDS CLOUDS IN STRONG THOUGH 06Z THURSDAY...BUT BOTH NAM AND GFS
WANT TO GO FULL VFR AT MSP BY THE END OF THE PERIOD.
RNH/EAU...THESE TERMINALS WILL FEEL BRUNT OF HEAVIEST SNOWFALL
THROUGH THE MORNING. EAU ALREADY HAS HAD SUSTAINED 3/4SM VSBYS FOR
THE LAST COUPLE OF HOURS...AND SEE NO REASON WHY THIS WILL NOT
CONTINUE TO BE THE CASE THROUGH AT LEAST 15Z. LOOKS LIKE AT LEAST
-SN WILL HOLD ON AT WIS TERMINALS TO ABOUT 00Z. STRONGEST WINDS
WILL ALSO LINGER LONGEST HEAR AND THEY WILL LIKELY HAVE BLSN ISSUE
THROUGH THE ENTIRE 24 HOURS. FOR CIGS...IFR OR LOWER WILL PERSIST
DURING HEAVIEST SNOW THIS MORNING...BUT PROXIMITY TO LOW WILL HOLD
IFR CIGS UNTIL CLOSER TO 00Z...WITH MVFR CIGS HOLDING THROUGH 06Z
THURSDAY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...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.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR BENTON-
DOUGLAS-KANABEC-KANDIYOHI-MEEKER-MILLE LACS-MORRISON-POPE-
STEARNS-STEVENS-SWIFT-TODD.
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 CHIPPEWA-LAC
QUI PARLE-REDWOOD-RENVILLE-YELLOW MEDICINE.
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/MPG
