FXUS63 KMPX 030025
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
625 PM CST WED DEC 2 2009
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED 339 PM CST WED DEC 2 2009/
NEXT WEATHER MAKER OF SIGNIFICANCE IS THE UPPER LOW DROPPING SE
OUT OF NORTH DAKOTA. AHEAD OF THIS CIRCULATION...THERE IS AN AREA
OF PV ADVECTION DEVELOPING FROM EASTERN SD INTO SW MN. THE RUC
CONTINUES TO DEVELOP THIS FORCING OVERNIGHT BUT THE MAIN FORCING
FROM THE UPPER LOW MOVES IN THURSDAY MORNING. IT LOOKS LIKE THE
NAM REFLEC SIMULATION IS A LITTLE TOO FAR EAST INTO NW MN THIS
AFTERNOON. THE WWD ESTIMATE OF SNOWFALL A TOUCH FARTHER WEST OVER
SW MN LOOK REASONABLE. H5 HEIGHT FALLS MAINLY OVER SE SD INTO
CENTRAL IA WOULD SUPPORT THIS AS WELL. WILL UP POPS A BIT AND RUN
THE BEST AREA FROM WEST CENTRAL INTO SOUTH CENTRAL MN. GENERAL
COLD CYCLONIC FLOW WILL DOMINATE THROUGH FRIDAY WITH AT LEAST
FLURRIES THE REMAINDER OF THURSDAY INTO THURSDAY NIGHT.
ANOTHER WEAK WAVE WILL DROP DOWN IN THE CYCLONIC FLOW ON FRIDAY
WITH A SMALL CHANCE OF MEASURABLE SNOW OVER THE NORTH AND EAST
PART OF THE CWA. CLOUDS MAY HOLD UP OVERNIGHT TEMPS A BIT ABOVE
GUIDANCE TONIGHT BUT THEN CLOSER TO GUIDANCE BEHIND THE DEPARTING
WAVE ON THURSDAY.
OTHERWISE THE SLIDE IN TEMPS SHOULD LAST INTO FRIDAY...AND THEN
A BIT OF MODERATION IN MAX TEMPS INTO THE WEEKEND AHEAD OF SOME
SURFACE DEVELOPMENT IN THE PLAINS. PRECIP CHANCES APPEAR TO BE ON
THE LOW SIDE WITH THE GENERAL WEST TO EAST UPPER JET THROUGH THE
CENTRAL PLAINS. WILL CONTINUE THE LOW CHANCE OF SNOW FOR SOUTHERN
MN. THE GFS ENSEMBLE POPS FOR FAR SOUTHERN MN DO NOT SHOW MUCH
VARIATION AMONG THE MEMBERS AND ARE STILL ONLY IN THE 20 RANGE ON
AVERAGE.
&&
.AVIATION.../00Z TAF ISSUANCE/
LOW PRESSURE OVER NORTH CENTRAL SD AND SOUTH CENTRAL ND MOVING
SSE. LATEST RUC SUGGESTS A SPLIT WITH ANOTHER UPPER TROUGH FROM
NORTHEAST MN INTO NORTHWEST ONTARIO. THIS HAS MANIFESTED ITSELF
WITH NORTHEAST COMPONENT TO THE UPPER FLOW MOVING SWWD INTO WEST
CENTRAL MN WITH A POCKET OF DRY AIR. UPPER LOW WILL THEN BEGIN AN
ARCING TURN AS IT REACHES EAST CENTRAL OR SOUTHEASTERN SD...LOOPING
ALONG THE MN/IA BORDER AND THEN INTO CENTRAL OR SOUTHERN WISCONSIN.
DETERMINISTIC 18Z NAM AND GFS BOTH SHOW UPPER LOW STRENGTHENING AS
THIS HAPPENS...AND 21Z RUC ALSO SHOWS STRENGTHENING.
BOTTOM LINE IS THAT NARROW CORRIDOR OF SNOW THIS EVENING FROM FAR
WEST CENTRAL INTO SOUTHWEST MN WILL PERSIST... THEN MORE SNOW WILL
DEVELOP ACROSS SOUTHERN AND CENTRAL MN THURSDAY MORNING AND MOVE
INTO WISCONSIN.
KAXN...DRY AIR FROM THE NORTHEAST HAS RESULTED IN CLOUDS LIFTING
TO 1500-3000 AT 23Z...BUT STREAMLINES SUGGEST AXN WILL REMAIN JUST
BARELY ON THE EASTERN EDGE OF IFR CIGS/VSBYS... WITH CORRIDOR OF
LIGHT SNOW THAT EXTENDS SSE FROM THE RED RIVER VALLEY HANGING
POSSIBLY ONLY A FEW MILES WEST OF KAXN. THUS KAXN MAY WAVER BACK
AND FORTH BETWEEN IFR AND MVFR VSBYS/CIGS THIS EVENING. MORE
DEFINITE CHANCE OF 1000-2000 CIGS LATE TONIGHT AS BETTER FORCING
ASSOCIATED WITH UPPER LOW EDGES EASTWARD.
KRWF...BAND OF SNOW FROM THE RED RIVER VALLEY WILL CONTINUE MOVING
SSE INTO KRWF THIS EVENING. SHOULD BE A BRIEF RISE IN VSBYS LATER
THIS EVENING BEFORE NEXT ROUND OF LIGHT SNOW TAKES IT BACK DOWN.
SOME POTENTIAL FOR VSBYS TO GO DOWN TO 1 OR 2 MILES.
KSTC...CLOUDS AROUND 3500-4500 SHOULD CONTINUE UNTIL LATE TONIGHT
OR DAYBREAK THURSDAY WHEN MVFR VSBYS AND CIGS DEVELOP ASSOCIATED
WITH BETTER FORCING ASSOCIATED WITH UPPER LOW.
KMSP...CLOUDS AROUND 3500-4500 SHOULD PERSIST UNTIL LATE TONIGHT
OR DAYBREAK THURSDAY WHEN MVFR VSBYS AND CIGS DEVELOP ASSOCIATED
WITH BETTER FORCING ASSOCIATED WITH STRENGTHENING UPPER LOW. SOME
POTENTIAL FOR VSBYS THURSDAY LATE MORNING OR AFTERNOON TO GO DOWN
TO 2 MILES.
KRNH...EXPECT CLOUDS CLOUDS OF 3500-4000 TO CONTINUE UNTIL DAYBREAK
THURSDAY WHEN MVFR VSBYS AND CIGS DEVELOP ASSOCIATED WITH BETTER
FORCING ASSOCIATED WITH STRENGTHENING UPPER LOW. SOME POTENTIAL
FOR VSBYS THURSDAY MIDDAY OR AFTERNOON TO GO DOWN TO 2 MILES.
KEAU...CLOUDS SHOULD REMAIN ABOVE MVFR UNTIL LATE TONIGHT OR
THURSDAY MORNING WHEN STRENGTHENING UPPER LOW GETS CLOSER. BETTER
FORCING DOES NOT ARRIVE UNTIL THURSDAY MIDDAY WHEN HAVE MAINTAINED
FLURRIES. MAY NEED TO INTRODUCE MVFR VSBY THURSDAY AFTERNOON IF
UPPER LOW MAINTAINS ITS INTENSITY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/TDK
