Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 231209 AAA
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
609 AM CST TUE DEC 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CST TUE DEC 23 2014

THERE WILL BE ONE LAST ROUND OF PRECIPITATION WITH THIS SYSTEM
BEFORE IT FINALLY EXITS THE AREA WEDNESDAY. TEMPERATURES ACROSS THE
ENTIRE UPPER MIDWEST ARE HOLDING STEADY IN THE LOW OR MID 30S WITH
REALLY NO COLD AIR ANYWHERE TO BE FOUND. THIS TREND WILL CONTINUE
TODAY MAKING FOR ANOTHER TRICKY SITUATION IN TERMS OF PRECIPITATION
TYPE. THE ONE THING TODAY HAS THAT PRIOR DAYS DID NOT IS MORE
INTENSE PRECIPITATION ASSOCIATED WITH DEFORMATION BANDING ON THE
BACKSIDE OF THE LOW. THIS SHOULD...ONE WOULD THINK...ALLOW FOR MORE
SNOW POTENTIAL DESPITE NEAR OR ABOVE FREEZING TEMPS. HOW MUCH OF AN
IMPACT IT WILL HAVE ON THE ROADS IS THE BIGGEST QUESTION...BUT IF
RATES INCREASE AS EXPECTED THEN THERE COULD BE AT LEAST SOME IMPACT
THIS MORNING FROM ALBERT LEA TO EAU CLAIRE AND LADYSMITH. THAT IS
WHERE THE HIGHEST POTENTIAL FOR ACCUMULATING SNOW WILL RESIDE THIS
MORNING AND EARLY AFTERNOON. INTENSITY AND THEREFORE AMOUNTS WILL
TAPER OFF TO THE WEST OF HERE...WITH AREAS WEST OF NEW ULM AND THE
TWIN CITIES PROBABLY NOT SEEING MUCH...IF ANY ACCUMULATING SNOW.

SNOW RATIOS USING THE AIR FORCE METHOD LEAVE A LOT TO BE DESIRED
WITH ITS 4 OR 5:1 VALUES. THE ROEBBER SNOW RATIO TECHNIQUE FROM
UW-MILWAUKEE ALSO LEANS TOWARD HEAVY SNOW RATIOS OF LESS THAN
9:1...ALTHOUGH THERE ARE SOME PROBABILITIES LEANING INTO THE AVERAGE
RANGE OF 9:1 TO 15:1 AS WELL. TOOK A COMPROMISE OF ALL OF THIS WITH
AN 8:1 RATIO OFFICIALLY. THIS LEAVES A SWATH OF 2 TO 3 INCHES OF WET
SNOW FROM KAEL TO KEAU. THE SNOW WILL TAPER OFF BY MID AFTERNOON
WITH ONLY DRIZZLE OR FLURRIES CONTINUING INTO TONIGHT AS THE MID
LEVELS DRY OUT. ADDED EAU CLAIRE COUNTY TO THE ADVISORY...AND
TRIMMED THE BACK END OF THE TIME TO 21Z INSTEAD OF 00Z.

DRIER AIR WILL WORK IN TONIGHT AND PUT AN END TO THE PRECIP FROM
NORTHWEST TO SOUTHEAST. CLOUDS AND FAIRLY UNIFORM TEMPS AROUND WILL
KEEP TEMPS FROM FALLING TOO MUCH...AND WILL PROBABLY REMAIN IN THE
LOW 30S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 AM CST TUE DEC 23 2014

LONG TERMS CONCERNS REMAIN THE DEVELOPMENT OF THE THURSDAY NIGHT/FRIDAY
SYSTEM AND THEN OVERALL PATTERN TOWARD COLDER WEATHER LATE IN THE
WEEKEND AND CONTINUING EARLY NEXT WEEK.

INITIALLY...IN THE WAKE OF TUESDAY SYSTEM...CLOUDS REMAIN ONCE AGAIN.
TEMPERATURES WILL REMAIN ON THE MILD SIDE AS WELL.

THE NEXT WAVE WORKS EAST LATER THURSDAY.  THE UPPER FLOW DOES APPEAR
TO BE PARTIALLY SPLIT...BUT THE SOUTHERN STREAM ENERGY LIFTS AHEAD
OF THE CANADIAN TROUGH AND THEY THEN PHASE AS THE SYSTEM LIFTS
THROUGH THE AREA FRIDAY. THERE SHOULD BE A FAIRLY DISTINCT
BAROCLINIC ZONE ASSOCIATED WITH THE TROUGH...AND ISENTROPIC
FORECASTS INDICATE A NICE PRECIPITATION BAND IS FORECAST ACROSS THE
CENTRAL CWA.  THIS SHOULD BE IN THE FORM OF SNOW AS TEMPERATURES
COOL DYNAMICALLY AS THE TROUGH LIFTS THROUGH THE AREA.  STILL SOME
QUESTION HOW FAR SOUTH THIS WILL DEVELOP SO WE CONTINUE THE THE HIGH
CHANCE POPS OVER THE CENTRAL CWA FOR NOW. THIS DOES HAVE THE
POTENTIAL FOR A HEADLINE TYPE EVENT.

THE GFS DRAGS COOLER AIR OR BELOW NORMAL TEMPERATURES OVER THE AREA
FOR THE WEEKEND. BOTH THE GFS AND ECMWF MOVE A 1030+MB HIGH OVER THE
NORTHERN PLAINS DURING THE PERIOD.  THE NEXT THREAT OF SNOW MOVES
INTO THE AREA SUNDAY NIGHT AND MONDAY AS THE LONG TERM MODELS DRAG A
FORMIDABLE ARCTIC FRONT THROUGH THE AREA. THE LONG TERM CFS ENSEMBLE
PLUMES CONTINUE THIS TREND...BUT ONLY FOR A SHORT TIME...WITH A
WARMING TREND DEVELOPING FOR LATER NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 609 AM CST TUE DEC 23 2014

CONDITIONS RANGE FROM LIFR NEAR AXN...TO HIGH END IFR OR MVFR
ELSEWHERE AT TAF ISSUANCE TIME. SNOW IS ADVANCING NORTH INTO SRN
MN WHICH WILL ROTATE NORTHEAST INTO WESTERN WI AND ERN MN LATER
THIS MORNING. THE BEST ACCUMULATIONS WILL BE NEAR EAU WHERE 3
INCHES ARE FORECAST. IFR OR LIFR CONDITIONS WILL ACCOMPANY THE
SNOW. THE SNOW WILL TAPER OFF EARLY TO MID AFTERNOON...BUT THE IFR
CONDITIONS WILL CONTINUE THROUGH JUST ABOUT THE WHOLE PERIOD.

KMSP...SNOW IS LOCATED JUST TO THE SOUTH NEAR NORTHFIELD AND
FARIBAULT WITH A MIX OF RAIN AND SNOW TO THE EAST ACROSS WI. THIS
PRECIPITATION WILL CONTINUE ADVANCING NORTH DURING THE NEXT COUPLE
HOURS AND STEADY SNOW SHOULD REACH MSP AROUND 15Z...IF NOT JUST A
BIT BEFORE. SNOW WILL TAPER OFF DURING THE EARLY AFTERNOON...BUT
FLURRIES ARE POSSIBLE THROUGH THE EVENING. MVFR CONDITIONS EARLY
THIS MORNING WILL DETERIORATE BACK TO IFR AS THE SNOW ARRIVES.
SNOW ACCUMULATION AROUND AN INCH IS EXPECTED.

/OUTLOOK FOR KMSP/
WED...MVFR. WINDS NW 10-15 KTS.
THU...VFR.  WINDS W 5-10 KTS.
FRI...MVFR WITH CHC -SN. WINDS NW 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR WIZ016-
     027-028.

&&

$$

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





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