Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 160356
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1056 PM CDT TUE APR 15 2014

.UPDATE...
ISSUED AT 514 PM CDT TUE APR 15 2014

ISSUED A WINTER WEATHER ADVISORY JUST TO THE WEST AND SOUTH OF THE
WINTER STORM WARNING AREA FOR LATE TONIGHT THROUGH WEDNESDAY
NIGHT. VARIOUS WRF SOLUTIONS SUPPORT MODERATE AREAS OF SNOW
ON THE PERIPHERY OF THE WARNING AREA LATE TONIGHT INTO WEDNESDAY
NIGHT...WHICH WAS ALREADY IN PLACE FROM THE DAY SHIFT. CONFIDENCE
IS HIGHEST ON AMOUNTS REACHING 4 TO 6 INCHES IN STEVENS...POPE...DOUGLAS
AND STEARNS COUNTIES WHERE LITTLE TO NO RAIN IS EXPECTED ON
WEDNESDAY. IT BECOMES MORE PROBLEMATIC ON SNOW AMOUNTS THE FARTHER
EAST YOU GO...ESPECIALLY ACROSS THE NORTH METRO AND INTO WEST
CENTRAL WISCONSIN ALONG HIGHWAY 64. THE THINKING WAS THAT THERE
COULD BE SEVERAL INCHES OF SNOW FALL QUICKLY IN THESE AREAS
WEDNESDAY MORNING BEFORE A MIX OR CHANGEOVER TO RAIN OCCURS...WITH A
CHANGE BACK TO ALL SNOW LATE IN THE DAY WITH MORE ACCUMULATION
LIKELY. THIS COULD IMPACT BOTH THE MORNING AND EVENING RUSH HOUR.
A FINAL CONCERN IS THAT CHIPPEWA COUNTY WI MAY APPROACH OR EXCEED
WARNING CRITERIA LATE WEDNESDAY MORNING AND IT MAY MAY NEED AN
UPGRADE TO A WARNING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 232 PM CDT TUE APR 15 2014

FOCUS IS ON THE SHORTWAVE TROUGH TRACKING FROM THE PACIFIC
NORTHWEST ACROSS THE NORTHERN ROCKIES ON AFTERNOON WATER VAPOR
IMAGERY. A HEALTHY LOW LEVEL JET WILL KICK IN OVERNIGHT AHEAD OF SAID
FEATURE...WITH WARM AIR ADVECTION PROCESSES ENSUING LOCALLY AFTER
06Z WEDNESDAY. EXPECT A BAND OF SNOW TO EXPAND WEST TO EAST ACROSS
CENTRAL MN INTO WEST CENTRAL WISCONSIN BETWEEN 06Z AND 12Z.
SOUTHERN SITES /SOUTH OF INTERSTATE 94/ COULD ESCAPE THIS PRIMARY
BAND OVERNIGHT...BUT A MORE WIDESPREAD/FORMIDABLE AREA OF PRECIP
WILL OVERSPREAD THE AREA DURING THE LATE MORNING AND AFTERNOON
HOURS ON WEDNESDAY. PRECIP TYPE IS CERTAINLY CHALLENGING WITH THIS
EVENT...BUT CONFIDENCE IS FAIRLY HIGH THAT THE PRIMARY FORM OF
PRECIP IN NORTHERN AREAS /LONG PRAIRIE TO CAMBRIDGE MN AND ALONG
AND NORTH OF HWY 8 IN WI/ WILL BE SNOW. ALL OF THE MODELS INDICATE
AT LEAST 6-10 INCHES WILL FALL IN THE WARNING AREA BETWEEN EARLY
WEDNESDAY MORNING AND THURSDAY MORNING...WITH 15.12Z RUNS OF THE
NAM...GFS...AND GEM MODELS EVEN INDICATING A BAND OF 12-18 INCHES
ACROSS POLK/BARRON/RUSK COUNTIES. WHILE THE FORCING IS CERTAINLY
THERE...COULD LOSE A FAIR AMOUNT OF THAT PRECIP AS RAIN IF THE
MODELS ARE OFF ON THEIR TIMING OF THE CHANGEOVER. HAVE THEREFORE
LEANED A BIT MORE CONSERVATIVELY TOWARD THE 15.12Z ECMWF...WHICH
FEATURES 5-10 INCHES ACROSS THE WARNING AREA...AND A ECMWF/NAM
BLEND FOR THE TWIN CITIES TO EAU CLAIRE...WHICH YIELDS 1-3 INCHES.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CDT TUE APR 15 2014

SPLIT FLOW WILL LEAD TO A RATHER QUIET PERIOD IN THE EXTENDED AS
TEMPERATURES GRADUALLY WARM TO NEAR THE SEASONAL AVERAGE BY THE
BEGINNING OF NEXT WEEK. THE BEST CHANCE FOR RAIN WILL BE SATURDAY
INTO SUNDAY IN ASSOCIATION WITH THE H850 THETA_E ADVECTION AS
NORTHWEST FLOW TRANSITIONS TO A MORE ZONAL PATTERN.

AT THE START OF THE PERIOD THURSDAY MORNING THE SURFACE RIDGE OF
HIGH PRESSURE WILL BE CENTERED ACROSS WESTERN MN AND GRADUALLY SHIFT
EASTWARD THROUGHOUT THE DAY. FORECAST SOUNDINGS SHOW A BACKING WIND
PROFILE IN THE LOWEST 10KFT...AND THE WEAK COLD AIR ADVECTION
TOGETHER WITH MID LEVEL CLOUDS WILL KEEP AFTERNOON HIGHS GENERALLY
IN THE LOWER 40S TO THE SOUTH...AND UPPER 30S ACROSS THE NORTH WHERE
THE FRESH SNOW IS EXPECTED.

A SHORTWAVE ON THE BACK SIDE OF A LOW AMPLITUDE LONGWAVE TROUGH WILL
BECOME ELONGATED INTO A STRIP OF POSITIVE VORTICITY AS IT RIDES THE
UPSTREAM RIDGES ACROSS THE UPPER MIDWEST FRIDAY. A FEW LIGHT
RAIN/SNOW SHOWERS ARE POSSIBLE...BUT THE PRECIP SHOULD REMAIN
CONFINED TO THE EASTERN DAKOTAS AND SOUTHWESTERN MN. THE BEST CHANCE
FOR PRECIP WILL BE OVER THE WEEKEND WITH THE AFOREMENTIONED THETA_E
ADVECTION DOWNSTREAM OF ANOTHER 500MB WAVE THAT IS FORECAST TO TAKE
ON A NEGATIVE TILT AS IT MOVES INTO CENTRAL CANADA AND HUDSON BAY.
THERMODYNAMIC PROFILES SUPPORT THIS PRECIP AS ALL RAIN...EXCEPT FOR
A FEW SNOW FLAKES IN WEST CENTRAL WI. AS OF NOW RAINFALL TOTALS LOOK
TO BE AROUND 0.25 TO 0.50 INCHES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1056 PM CDT TUE APR 15 2014

LATEST SHORT TERM SOLUTIONS ARE INDICATING A SLOWER EVOLUTION TO
THE LOW PRESSURE SYSTEM PASSING ACROSS THE TAF SITES ON
WEDNESDAY/WEDNESDAY NIGHT. THIS RESULTS IN WARMER AND SOMEWHAT
DRIER LOW LEVEL CONDITIONS ON WEDNESDAY FROM KMSP ON EAST...WHILE
COLDER CONDITIONS AND MORE SNOW ARE NOW INDICATED FOR KAXN AND
KRWF. WORKED THESE NEW IDEAS INTO THE TAFS. THIS WOULD PLACE THE
BEST SNOW ACCUMULATION ACROSS CENTRAL INTO SOUTHWEST AREAS OF MN
DURING THE AFTERNOON AND EVENING. SNOW WOULD EVENTUALLY WORK INTO
THE EASTERN TAF SITES LATER IN THE EVENING AND BEYOND THE CURRENT
TAF PERIOD. STRONG EASTERLY WINDS BY DAYBREAK WEDNESDAY WITH
SPEEDS IN THE 15-20 KNOT RANGE WITH GUSTS IN THE MID 20 KNOT
RANGE. THESE WILL CONTINUE THROUGH THE DAY.

KMSP...IMPROVED THE TAF DURING THE OVERNIGHT AND EARLY MORNING
HOURS WITH WARMER AND DRIER LOW LEVEL CONDITIONS INDICATED. MVFR
CONDITIONS DEVELOPING IN THE AFTERNOON ALONG WITH LIGHT RAIN. RAIN
THEN CHANGING TO SNOW DURING THE LATE EVENING HOURS.

/OUTLOOK FOR KMSP/

THU...VFR. WINDS NNE 10-15 KTS.
FRI...VFR. CHANCE MVFR FRI NIGHT WITH RAIN/SNOW. WINDS NE 5-10 KTS.
SAT...CHANCE MVFR WITH RAIN/SNOW. WINDS E-SE 10-15 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 4 AM CDT THURSDAY
     FOR MNZ042>045-050-052-053.

     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 4 AM CDT THURSDAY
     FOR MNZ051-061-063.

     WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 4 AM CDT THURSDAY
     FOR MNZ041-047>049.

WI...WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 4 AM CDT THURSDAY
     FOR WIZ014.

     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 7 AM CDT THURSDAY
     FOR WIZ025-027.

     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 4 AM CDT THURSDAY
     FOR WIZ023.

     WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 7 AM CDT THURSDAY
     FOR WIZ015-016.

&&

$$

UPDATE...RAH
SHORT TERM...LS
LONG TERM...JRB
AVIATION...RAH







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