000
FXUS63 KMPX 050504
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1104 PM CST WED DEC 4 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 320 PM CST WED DEC 4 2013

DEEPENING LOW PRESSURE WAS LOCATED IN NORTHEAST IOWA AT MID
AFTERNOON. THE LOW WILL CONTINUE TO STRENGTHEN AS IT MOVES
NORTHEAST ACROSS WISCONSIN...LAKE SUPERIOR...AND INTO ONTARIO
OVERNIGHT. THE CC PRODUCT FROM THE KMPX DUAL POL RADAR NICELY
DEPICTED THE SNOW/MIX PRECIPITATION LINE MOVING SLOWLY EAST ACROSS
THE ST CROIX RIVER VALLEY INTO WISCONSIN EARLY THIS AFTERNOON.
850MB TEMPERATURES OVER EAU CLAIRE REMAIN VERY WARM...BUT WILL
COLLAPSE DURING THE LATE AFTERNOON WITH RAIN CHANGING TO SLEET AND
SNOW AND THEN TO ALL SNOW. SO...PORTIONS OF WEST CENTRAL WISCONSIN
WILL SEE LIMITED SNOWFALL TOTALS DUE TO THE EXPECTED LOW LEVEL
WARMTH. STILL...SLEET AND FREEZING RAIN WILL CERTAINLY HAVE AN
IMPACT ON TRAVEL CONDITIONS THERE. WIDESPREAD SNOWFALL WILL
CONTINUE LIFTING NORTH THROUGH MINNESOTA FOR THE REMAINDER OF THE
AFTERNOON AND INTO THE EVENING. THE FORECAST CARRIES LIKELY POPS
THROUGH 03Z ACROSS MUCH OF THE AREA. THE 15Z RUN OF THE HOPWRF
SUPPORTED THIS IDEA AS IT DEVELOPED A SECONDARY AREA OF SNOW
DEVELOPING AROUND 00Z NEAR THE SOUTH DAKOTA BORDER AND MOVING ENE
THROUGH 06Z ACROSS CENTRAL MN. THIS SECONDARY AREA WILL BE FIRMLY
IN THE COLD AIR THAT IS COMING...MEANING IT WILL BE MUCH LIGHTER
/WITH HIGHER SNOW TO LIQUID RATIOS/. THE CONCERN WITH THIS ROUND
OF LIGHT SNOW IS THE BLOWING SNOW AND THE POOR VISIBILITIES THAT
IT MAY CAUSE FROM WEST CENTRAL INTO SOUTH CENTRAL MINNESOTA.
THEREFORE...WITH THE POTENTIAL FOR WHITE-OUT CONDITIONS WEST AND
SOUTH...ACCUMULATING SNOW SLOWLY DIMINISHING NORTH AND MIXED
PRECIPITATION CHANGING TO ALL SNOW EAST...WILL KEEP CURRENT
HEADLINES AS THEY ARE.

THE STRONG NORTHWEST WINDS WILL USHER IN MUCH COLDER AIR INTO THE
REGION OVERNIGHT...AS TEMPERATURES IN THE 20S AND 30S THIS
AFTERNOON PLUMMET OVERNIGHT TO NEAR ZERO ACROSS WESTERN MN AND
AROUND 10 ABOVE IN WESTERN WI. WIND CHILL VALUES WILL DROP INTO
THE MINUS TEENS OVERNIGHT ACROSS THE AREA. IN ADDITION... EXPECT
TO SEE FLURRIES THURSDAY MORNING. TEMPERATURES THURSDAY REALLY
WILL NOT MODERATE AS COLD AIR ADVECTION CONTINUES ON THE BACK SIDE
OF THE EXITING LOW PRESSURE SYSTEM.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM CST WED DEC 4 2013

THE TWO WEATHER HIGHLIGHTS IN THE EXTENDED ARE THE COLD
TEMPERATURES/WIND CHILLS...AND THE CHANCE FOR LIGHT SNOW SUNDAY
AND MONDAY. AT THE START OF THE PERIOD...BITTERLY COLD AIR WILL
BE IN PLACE ACROSS THE REGION...BUT THE COLD ADVECTION WILL HAVE
ENDED FOR THE MOST PART. 3HR SURFACE PRESSURE RISES OFF THE NAM
ARE ON THE ORDER OF 2MB/3HR...SO WINDS WILL DECREASE OVERNIGHT TO
AROUND 10MPH. LOW TEMPERATURES WILL DROP TO NEAR -15F ACROSS
WESTERN MN...AND -5F IN EASTERN MN AND WESTERN WI. WIND CHILL
VALUES WILL BE -20 TO -30F ON FRIDAY MORNING...SO WILL LIKELY
ADDRESS THESE WITH WIND CHILL ADVISORIES ONCE THE WINTER STORM
WARNING EXPIRES THURSDAY MORNING. THE COLD AIR WILL REMAIN IN
PLACE THROUGHOUT THE PERIOD...WITH TEMPERATURES EXPECTED TO BE 20
TO 30 DEGREES BELOW THE SEASONAL AVERAGE FOR EARLY DECEMBER.

THE NEXT FEATURE OF INTEREST IS THE POTENTIAL FOR A LOW DENSITY
SNOWFALL CENTERED AROUND SUNDAY NIGHT. THE GFS/GEM/ECMWF 04.12 ALL
HAVE A SHORTWAVE MOVING SOUTHEAST OF THE REGION. DESPITE THE
4-CORNERS ORIGINATION...THE THERMAL PROFILE OF THIS WAVE WILL BE
MUCH MORE CLIPPER LIKE IN NATURE. FORECAST SOUNDINGS OFF THE GFS
SHOW LIGHT WINDS VEERING WITH HEIGHT AND A DEEP DENDRITIC ZONE.
THIS FITS THE CONCEPTUAL MODEL OF HIGH SNOW RATIOS...SO HAVE
INCREASED THE VALUES IN EXCESS OF 30:1. ALTHOUGH QPF AMOUNTS WILL
BE LIGHT...AS OF NOW COULD SEE AROUND 3 INCHES IN SOUTHEASTERN MN
AND WESTERN WI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1053 PM CST WED DEC 4 2013

PRECIPITATION HAS JUST ABOUT ENDED FOR ALL TAF SITES...THOUGH
PERIODS OF BLOWING/DRIFTING SNOW WILL BE AN ISSUE FOR MAINLY KAXN
AND KRWF WHERE WINDS WILL BE STRONGEST. BLOWING/DRIFTING WILL BE
MORE SPORADIC IN CENTRAL MN INTO WRN WI...BUT CANNOT BE RULED OUT
ALTHOUGH WILL RUN WITH VFR VSBY. THE ISSUE OF BLOWING/DRIFTING IS
MITIGATED BY MIDDAY THU WHEN THE STRONG W WINDS BEGIN TO DIMINISH.
THE MAIN ISSUE WILL BE CEILINGS WHICH WILL PRIMARILY LINGER IN THE
MVFR RANGE...THOUGH A FEW REPORTS OF IFR HEIGHT ARE NOT
UNREASONABLE. CEILINGS WILL GRADUALLY IMPROVE DURG THE DAY
TMRW...NOT SO MUCH LIFTING AS IT WILL BE SCATTERING OUT BEFORE
ONLY HIGH CIRRUS REMAINS TMRW NIGHT.

KMSP...WILL INITIALIZE WITH MVFR CEILINGS...WITH HEIGHTS ABOVE
1700 FT. AM EXPECTING CEILINGS TO REMAIN ABOVE 1700 FT BUT CLOSE
TO SUNRISE...CEILINGS CLOSER TO 1500 FT MAY DEVELOP BUT CHANCES
ARE LOW. MVFR CIGS WILL THEN PREVAIL THRU MUCH OF THE DAY BEFORE
SCATTERING OUT LATE...RESULTING IN VFR. NO VSBY RESTRICTIONS
ANTICIPATED THOUGH SOME BLOWING/DRIFTING REPORTS CAN BE EXPECTED
THRU DAYBREAK. STRONG GUSTY W WINDS WILL PERSIST THRU MIDDAY THEN
GRADUALLY DIMINISH.

/OUTLOOK FOR KMSP/
FRI...VFR. W WIND 5-15 KT.
SAT...VFR. SW WIND 5-10 KT.
SUN...MVFR CONDS LIKELY. IFR CONDS POSSIBLE. CHC -SN. SE WIND 5-10
KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR MNZ041>045.

WI...NONE.
&&

$$

SHORT TERM...SPD
LONG TERM...JRB
AVIATION...JPC