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000
FXUS63 KMPX 021812
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1212 PM CST MON DEC 2 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CST MON DEC 2 2013

PATCHES OF SNOW AND SLEET HAVE BEEN SLIDING ACROSS THE MN COUNTIES
OVERNIGHT WITH MODEST ISENTROPIC LIFT...BUT AMOUNTS HAVE BEEN LIGHT.
THE MAIN SHOW IS STILL UP IN NORTH DAKOTA WHICH WILL SLIDE SOUTHEAST
THROUGH THE DAY. MOISTURE WILL INCREASE WITH ISENTROPIC LIFT STILL
IN PLACE SO A SOLID BAND OF PRECIPITATION IS FORECAST TO SHIFT INTO
CENTRAL MN LATE THIS MORNING AND ERN MN/WRN WI BY THIS AFTERNOON.
RAISED POPS QUITE A BIT FOR THESE AREAS...NOW IN THE 80-90 PERCENT
RANGE. FURTHER SOUTH AND WEST...DRIER MID LEVEL AIR AND NEUTRAL OR
SLIGHT ISENTROPIC DOWNGLIDE WILL ENSURE A DRIER FORECAST.

THERMAL PROFILES WARM DURING THE DAY...ESPECIALLY JUST ALOFT. MAINLY
SNOW IS EXPECTED NORTH OF A LINE FROM ALEXANDRIA TO CAMBRIDGE AND
BLOOMER WITH 3 OR 4 INCHES POSSIBLE. BOUNDARY LAYER TEMPS WARM
ENOUGH TO INCLUDE A MIX OF RAIN AND SNOW OR RAIN FURTHER SOUTH.
PLAN TO ISSUE A WINTER WEATHER ADVISORY FOR THE AREAS EXPECTED TO
REMAIN MAINLY SNOW...BUT THE DAY SHIFT WILL WATCH FOR TRENDS AND
MAKE UPDATES AS NECESSARY.

DRY MID LEVEL AIR WILL SHIFT NORTHEAST THIS EVENING AND WILL RESULT
IN A TAPERING OF STEADIER PRECIPITATION. HOWEVER...THE COLUMN IS
STILL EXPECTED TO BE SATURATED BELOW 4-5 KFT WITH SOME OMEGA
PRESENT. DENDRITIC GROWTH ZONE WILL BE ABOVE 12KFT AND DRYING OUT
NICELY AFTER 00Z. THUS...DRIZZLE OR FREEZING DRIZZLE WILL TAKE OVER
FOR TONIGHT. DON/T ANTICIPATE TOO MANY PROBLEMS ON TREATED ROADS
WITH TEMPS IN THE UPPER 20S TO LOWER 30S...BUT SOME OF THE UNTREATED
SURFACES MAY BECOME SLICK.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 339 AM CST MON DEC 2 2013

OVERALL DEVELOPMENT OF UPPER TROUGH OVER THE WESTERN CONUS STILL
UNCERTAIN. DETERMINISTIC MODELS CONTINUE TO DIVERGE QUITE A BIT.
THE NAM/GFS HAVE BEEN PRETTY CONSISTENT ON DRIVING UPPER
TROUGH/CLOSED CIRCULATION OVER THE NORTHERN MN INTO WEDNESDAY. THE
GEM/ECMWF/UKMET ARE MUCH SLOWER...DRIVING JET ENERGY OVER THE
SOUTHWEST CONUS TUESDAY INTO TUESDAY NIGHT. THE PNA TELECONNECTION
(NEGATIVE) IS FAVORING MORE OF THE DEVELOPMENT OF THE WESTERN
CONUS TROUGH...WITH HIGHER HEIGHTS LIFTING OVER ALASKA. THIS WILL
DRIVE THE COLD AIR SOUTH AND EAST IN THE TUESDAY/WEDNESDAY TIME
FRAME. LEE CYCLOGENESIS IS CERTAINLY POSSIBLE WITH THE ECMWF
HINTING AT A POSSIBLE SIGNIFICANT COLORADO LOW LIFTING NORTHEAST
OVER WISCONSIN WEDNESDAY. THE FIM MODEL WAS ALSO SHOWING THIS
SOLUTION AT 12Z SUN. FOR NOW...WILL TRY AND FOLLOW MORE OF THE
ECMWF/GEM/UKMET SOLUTION FOR NOW. THIS WILL BE DIFFICULT FOR
P-TYPE DISCERNMENT IN THE LONGER TERM. THE FRIGID AIR STILL
PROGGED TO AFFECT THE AREA WEDNESDAY NIGHT THROUGH THE WEEKEND.

FOR TUESDAY/TUESDAY NIGHT...THE DETERMINISTIC ECMWF AND GEM CONTINUE
TO DEVELOP SOME QPF OVER THE NORTHEAST AND EASTERN CWA. WILL
CONTINUE HIGHER POPS THIS REGION. GRIDDED SNOW ACCUMULATION SHOWS
A GENERAL 3-5 INCH SNOW POSSIBLE OVER THE NORTHERN TIER COUNTIES
DURING THIS 24 HOUR PERIOD. WITH THE FAVORED MODELS A BIT COOLER
THAN THE OTHERS...MUCH OF THIS WILL BE SNOW OVER THE NORTH. COULD
SEE A RAIN SNOW MIX YET IN THE SOUTH...CHANGING OVER TO ALL RAIN
AS THE ELEVATED WARM LAYER DOES LIFT NORTH A BIT. THIS WILL LIMIT
ANY SIG ACCUMULATION OVER THE SOUTHERN CWA TUESDAY.

FOR WEDNESDAY/WEDNESDAY NIGHT...THE MODELS DIVERGE THE GREATEST
HERE. THE FAVORED MODELS DRAG A INVERTED TROUGH OVER THE AREA
INTO WEDNESDAY...WITH LEE CYCLOGENESIS POSSIBLE DURING THIS
PERIOD...LIFTING NORTHEAST AFFECTING THE WESTERN GREAT LAKES. IT
IS HOPED THE MODELS COME INTO BETTER AGREEMENT WITH THIS MORNINGS
RUN...AS THE WESTERN TROUGH MOVES ASHORE. WILL DELAY COLDER
TEMPERATURES UNTIL LATER WEDNESDAY FOR NOW AS WELL. ANOTHER 3-6
INCH SNOW IS POSSIBLE DURING THIS PERIOD OVER THE NORTHEAST
PORTION OF THE CWA...IF THE ECMWF DOES VERIFY.  AS THE COLD AIR
ARRIVES...WIND CHILLS WILL DRIVEN SOUTH INTO THE DANGEROUS
CATEGORY...THURSDAY NIGHT INTO THE WEEKEND.

CONFIDENCE NOT HIGH ENOUGH FOR A 3RD-4TH PERIOD WATCH FOR THE
NORTHERN CWA...BECAUSE OF THE LARGE SCALE MODEL DIFFERENCES. STAY
TUNED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1212 PM CST MON DEC 2 2013

MAIN CONCERN FOR THIS AFTERNOON AND EARLY TONIGHT IS THE PRECIP
TYPE WITH THE ECHOES MOVING ACROSS MN/WI. LATE MORNING OBSERVATIONS
INDICATE RAIN BETWEEN KRWF AND THE TWIN CITIES ON NORTH TO NEAR
KSTC. SHORT TERM SOLUTIONS VARY ON WHETHER THE PRECIP STAYS AS ALL
RAIN DURING THE LATE AFTERNOON AND EVENING AS IT MOVES ACROSS THE
TWIN CITIES AND INTO WEST CENTRAL WI. WENT WITH A RAIN SCENARIO
FOR KMSP LATE THIS AFTERNOON WITH RAIN AND SNOW AT KEAU AND MAINLY
SNOW AT KRNH... WHERE THE LOW LEVEL THERMAL PROFILE STRUGGLES TO
WARM. KSTC AND KAXN ARE ON THE EDGE OF THE WARMER LOW LEVEL AIR
BUT WITH STRONG FORCING MOVING THROUGH THIS AFTERNOON... STAYED
WITH A SNOW SCENARIO. THE PRECIP DIMINISHES THIS EVENING FROM SW
TO NE. THIS OPENS THE DOOR FOR DZ/FZDZ WITH THE LOSS OF ICE IN THE
CLOUDS ABOVE. ALONG WITH THIS COMES LOWERING CEILINGS AND VSBYS
DUE TO THE VERY MOIST LOW LEVEL CONDITIONS AND LIGHT WINDS. IFR OR
LOWER CIGS/VSBYS FORECAST FOR THE LATTER HALF OF THE TAF PERIOD.

KMSP...TWO BANDS OF PRECIPITATION TO DEAL WITH THIS AFTERNOON. THE
FIRST IS EARLY ON WITH A MIX OF -RASN. THEREAFTER THINKING MORE
-RA. THE BACK EDGE OF THE -RA SHOULD BE THROUGH BY EVENING WITH
AREAS OF DRIZZLE THROUGH THE OVERNIGTH HOURS ALONG WITH IFR
CIGS/VSBYS.

/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS. SN LIKELY. ESE WINDS 10 KTS.
WED...MVFR CIGS. CHC SN. WINDS NW 15-25 KTS.
THU...MVFR CIGS POSSIBLE. WINDS WNW 10-15 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 3 AM CST TUESDAY FOR MNZ041>045-
     047>053.

WI...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
     TUESDAY FOR WIZ014>016.

&&

$$

SHORT TERM...BORGHOFF
LONG TERM...DWE
AVIATION...RAH