FXUS63 KMPX 150931
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
331 AM CST TUE DEC 15 2009
.DISCUSSION...
SURFACE ANALYSIS THIS MORNING SHOWS 1036MB HIGH CENTERED FROM ERN
NEB NW BACK INTO ERN MONTANA. THIS PUTS THE CWA ON COLD SIDE OF
HIGH...BUT TEMPS HAVE BEEN SOMEWHAT SLUGGISH TO RESPOND...THANKS IN
LARGE PART TO WEAK SHORTWAVE MOVING ACROSS NRN MN THAT HAS SPREAD
CLOUD COVER ACROSS THE AREA. THE BACK EDGE OF CLOUDS HAS MOVED OUT
OF WRN MN AND THE DAKOTAS...BUT EVEN HERE TEMPS HAVE BEEN SLOW TO
DROP...SO LIKELY NOT GOING TO SEE TEMPS THIS MORNING AS COLD AS
ORIGINALLY THOUGHT. THIS HAS ALSO RESULTED IN WIND CHILL VALUES
BEING A BIT WARMER THAN FORECAST...WITH ONLY A HANDFUL OF SITES OUT
WEST GETTING TO OR BELOW -25F THIS MORNING...THOUGH MANY AIRPORTS
ACROSS MN ARE SHOWING WIND CHILLS OF -20F OR LESS...SO WILL KEEP THE
WIND CHILL ADVISORY GOING THROUGH 17Z. DESPITE THE WARMER STARTING
POINT THOUGH...MIX DOWN TOOL TO H95 FROM BOTH 00Z NAM/GFS STILL
SUGGESTS TEMPS WILL STRUGGLE TO SNEAK ABOVE ZERO THIS
AFTERNOON...WITH AREAS FROM LITTLE FALLS BACK TO MORRIS LIKELY NOT
EVEN SEEING ZERO. THIS IS MUCH COOLER THAN THE MAV...BUT FAIRLY
SIMILAR TO COOLER MET GUIDANCE.
FOR TONIGHT...CENTER OF SFC HIGH WILL SLIP INTO ERN IL...WHICH WILL
PUT CWA INTO SRLY FLOW AND RATHER IMPRESSIVE WAA. IN FACT...BY 12Z
WEDNESDAY H85 TEMPS ARE FORECAST BY ALL GUIDANCE TO HAVE WARMED TO
NEAR 0C IN THE SW...THIS IS UP FROM VALUES AROUND -17C THIS MORNING.
SREF PLUMES FROM BOTH THE 21Z AND 03Z RUNS SHOW ALL SITES WARMING
OVERNIGHT...WITH THE WARMING STARTING AT MVE AROUND 00Z...MSP 03Z...
AND EAU 06Z. NEEDLESS TO SAY...HAVE NON-DIURNAL CURVE FOR TEMPS
TONIGHT...FOLLOWING THE SREF TREND. WILL ALSO HAVE TO EYE ANOTHER
WEAK SHORTWAVE PASSING TO THE NORTH OVERNIGHT. GFS SHOWING DECENT
FGEN FROM H85-H7 ON ELEVATED WARM FRONT AND MOIST UPGLIDE ON THE
280/285K SFCS NOSING DOWN TOWARD CENTRAL MN. SREF PROBS ALSO HINTING
AT SOME LOW END SNOW CHANCES NOSING DOWN INTO NRN CWA WEDNESDAY
MORNING...BUT OUTSIDE OF THAT...NO OTHER GUIDANCE HINTING AT THIS
WAVE DOING MUCH...SO KEPT FORECAST DRY FOR NOW.
FOR THE REST OF THE WEEK...H5 RIDGE FORECAST TO STRENGTHEN ACROSS
THE ROCKIES...WITH DEEP H5 LOWS SETTING UP NE OF MAINE AND OVER
ALASKA AS A STRONG REX BLOCK HIGH DEVELOPS FROM THE NRN ATLANTIC
ACROSS GREENLAND AND INTO NRN CANADA. GFS/ECMWF/GEM ALL HANDEL THIS
COMPLEX FLOW PATTERN IN SLIGHTLY DIFFERENT WAYS...BUT ALL INDICATE
POTENTIAL SHORTWAVE PASSAGES THURSDAY AND AGAIN FRIDAY. NONE OF
THESE PIECES OF ENERGY LOOK ALL THAT ORGANIZED...WITH THURSDAYS
SYSTEM AGAIN BRUSHING BY TO THE NORTH. ECMWF/GFS TAKE THE FRIDAY
WAVE SW OF AREA...BUT NAM/GEM/SREF BRING IT AND SOME LIGHT QPF
CLOSER TO THE AREA...SO WILL CONTINUE MENTION OF SLIGHT CHANCE OF
-SN FROM FRIDAY INTO SATURDAY. ON SATURDAY...GFS/ECMWF BRING ANOTHER
CANADIAN HIGH INTO THE UPPER MIDWEST...THOUGH ARCTIC AIR IS FORECAST
TO BE OVER ASIA AND ALASKA...WHICH MEANS AIRMASS FROM SATURDAY ON
WILL BE OF CONTINENTAL POLAR ORIGIN...STILL COLD WITH BELOW NORMAL
TEMPERATURES...JUST NOT AS COLD AS WILL BE SEEN TODAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
WEAK VORT APRCHG KFAR MVG EAST ARND 30KTS SPRDG BAND CLDS AND SCT
-SN MAINLY ACRS N MN. A BRF PRD OF 5SM -SN PSBL AT AXN TIL ARND
08Z AND PERHAPS AT STC BTWN 07Z AND 10Z. REMAINING TAF SITES WL
HAVE A 2-4 HOUR WINDOW FOR CIGS 3-5K. SEE SPECIFIC TAFS FOR
TIMING. BAND OF BIT STRONGER SFC WNDS ALSO APPEARING IN METARS
ACRS N NODAK INTO NW MN BHD VORT. MAY SEE SOME WINDS IN 10 TO 15
KT RANGE MAINLY AT AXN AND STC DVLPG BFR 12Z.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 11 AM CST THIS MORNING FOR ANOKA-
BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-
DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE
LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
&&
$$
MPG/BAP
