Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 281746
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1146 AM CST SAT FEB 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST SAT FEB 28 2015

THE SHORT TERM CONCERN IS TIMING OF CLOUDS AND THREAT OF LIGHT
SNOW/FLURRIES INTO TONIGHT.

RETREATING HIGH PRESSURE TO THE SOUTHEAST THIS MORNING.  THIS HAS
ALLOWED A SOUTHERLY WIND TO BE ESTABLISHED OVER MOST OF THE CWA.
PRESSURE GRADIENT AND PRESSURE FALLS DEVELOPING TO THE WEST...AHEAD
OF THE NEXT WEAK SURFACE FRONT MOVING INTO THE WESTERN DAKOTAS.
THIS FEATURE MOVES EAST TODAY.  ISENTROPIC LIFT...ALBEIT
WEAK...MOVES NORTH AND EAST ACROSS MOST OF MN PORTION OF THE CWA
DURING THE DAY.  THIS SHOULD INCREASE THE CLOUD COVER AND THERE IS A
THREAT OF SOME LIGHT SNOW OR FLURRIES TONIGHT AHEAD OF THE
FRONT/UPPER WAVE.  THIS FEATURE REMAINS WEAK...AND BUFKIT PROFILES
ARE INDICATING RATHER SHALLOW MOIST LAYER.  IT DOES APPEAR DEEP
ENOUGH OVER THE NORTHERN PORTION TO MENTION SLIGHT CHANCE POPS AT
THIS TIME.

CLOUDS DROP SOUTH AND EAST WITH THE FEATURE AND SHOULD GRADUALLY
MOVE EAST THROUGH 12Z SUNDAY. THE AIR BEHIND THE SYSTEM ISNT MUCH
COLDER THIS TIME AROUND...WITH THE BETTER COOLING LOCKED FARTHER
NORTH. HIGHS IN THE 20S SHOULD ONCE AGAIN BE FOUND OVER THE CWA.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 404 AM CST SAT FEB 28 2015

ONLY REAL CONCERN IN THE LONG TERM IS THE SYSTEM FOR EARLY NEXT
WEEK. ALL AVAILABLE GUIDANCE HAS SHOWN A NORTHWARD SHIFT
OVERNIGHT. IN FACT...A DPROG/DT ON THE GFS SHOWS EACH OF THE LAST
FOUR RUNS /EXCEPT THE INCOMING 06Z RUN/ HAD SOME SLIGHT DEEPENING
AND A MORE NORTHERLY TRACK. MAIN REASON FOR THE SHIFT IS A WEAKER
NORTHERN WAVE ACROSS CANADA AND A LATER ARRIVAL OF THE ARCTIC
FRONT. GFS ENSEMBLES ARE BECOMING MORE TIGHTLY CLUSTERED AND ITS
AVERAGE LOW TRACK FROM ERN CO/NWRN KS TO SERN IA TO NEAR MILWAUKEE
BY TUESDAY EVENING IS IN CLOSE AGREEMENT WITH THE DETERMINISTIC
GFS/ECMWF. THUS... CONFIDENCE IS BEGINNING TO INCREASE THAT THE
SOUTHEASTERN HALF OF MINNESOTA AND ALL OF WISCONSIN WILL SEE SOME
ACCUMULATING SNOW WITH THE QUESTION BEING HOW MUCH.

RIDGING OVER THE GULF OF MEXICO WILL ALLOW FOR RICH MOISTURE TO
STREAM NORTHWARD INTO THE PLAINS MONDAY. BY MONDAY NIGHT...INCREASING
MOISTURE ADVECTION AND ISENTROPIC LIFT ACROSS THE UPPER MIDWEST
WILL ALLOW SNOW TO BLOSSOM IN ADVANCE OF THE SYSTEM AND NORTH OF
THE WARM FRONT. THE SNOW WILL BECOME STEADIER AND MORE INTENSE AS
THE UPPER WAVE ARRIVES TUESDAY MORNING. BY TUESDAY AFTERNOON
ISENTROPIC DOWNGLIDE AND RAPID DRYING WILL ERODE THE SNOW SHIELD
WITH MOST AREAS DRY BY 00Z.

THE POSITIVELY TILTED NATURE OF THE SYSTEM AND A SHEARING OF THE
UPPER WAVE WITH TIME WILL LIMIT THE DURATION OF MOST INTENSE SNOW.
THEREFORE NOT ANTICIPATING A MONSTER SNOWFALL...BUT SEVERAL INCHES
ARE CERTAINLY POSSIBLE.

THE SECOND ASPECT OF THIS STORM TO WATCH IS THE PASSAGE OF THE
ARCTIC FRONT TUESDAY AFTERNOON. 925 MB WINDS INCREASE TO AS MUCH
AS 40 KT IMMEDIATELY BEHIND THE FRONT WITH THE MAX ISOTACHS
SLIDING SE ACROSS THE MN RIVER VALLEY BETWEEN 18Z TUE AND 03Z
WED. NEEDLESS TO SAY...FOLLOWING A FRESH SNOWFALL THIS WOULD LEAD
TO QUITE A BIT OF BLOWING SNOW FOR A TIME.

COLD TEMPERATURES RETURN WEDNESDAY BUT THE TROUGH WILL LIFT OUT
LATE WEEK WITH A MILDER AND QUIET PATTERN TO FOLLOW FOR NEXT
WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1145 CST SAT FEB 28 2015

HIGH CLOUDS ARE BEGINNING TO MOVE INTO OUR REGION FROM THE WEST
AS AN UPPER LEVEL SHORTWAVE APPROACHES OUR AREA...BUT VFR
CONDITIONS WILL PERSIST THROUGH THE EARLY EVENING AT ALL
TERMINALS. BREEZY CONDITIONS CAN BE EXPECTED WITH SOUTHERLY WINDS,
ESPECIALLY AT AXN WHERE GUSTS TO AROUND 20 KTS WILL CONTINUE THIS
AFTERNOON. AS THE UPPER LEVEL FEATURE MOVES THROUGH TONIGHT THE
CLOUD DECK IS EXPECTED TO LOWER...AND MVFR CIGS ARE POSSIBLE AT
MOST TERMINALS. THIS FEATURE WILL ALSO PRODUCE A FEW FLURRIES
OVERNIGHT IN CENTRAL MN AND WESTERN WI...BUT VISIBILITY SHOULD NOT
BE SIGNIFICANTLY IMPACTED. VFR CONDITIONS WILL RETURN TO ALL
TERMINALS SUNDAY MORNING AS THE LOW CLOUDS AND SCATTERED FLURRIES
MOVE OFF TO THE EAST.

KMSP...
VFR CONDITIONS WILL PERSIST FOR THE REMAINDER OF THE
AFTERNOON...WITH A FEW SOUTHERLY WIND GUSTS TO 15-17 KTS
POSSIBLE. LOWER CLOUDS WILL MOVE IN DURING THE EVENING...WITH MVFR
CIGS POSSIBLE THROUGH EARLY SUNDAY MORNING. A FEW FLURRIES CANNOT
BE RULED OUT FROM THE LATE EVENING THROUGH EARLY MORNING
SUNDAY...BUT SHOULD MAINLY REMAIN TO THE NORTH AND EAST OF MSP.
WINDS WILL SHIFT TO THE SW SUNDAY MORNING...AND BECOME WESTERLY
SUNDAY AFTERNOON.

/OUTLOOK FOR KMSP/
MON...VFR WITH MVFR/IFR -SN LIKELY LATE. WINDS S AT 10KTS.
TUE...MVFR/IFR AND SN LIKELY. WINDS S 10KTS BECOMING NW 20G30KTS.
WED...VFR LIKELY. WINDS NW 15G20KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

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


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