Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 271813
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
113 PM CDT FRI MAR 27 2015

.UPDATED FOR 18Z AVIATION DISCUSSION...
ISSUED AT 109 PM CDT FRI MAR 27 2015

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT FRI MAR 27 2015

HIGH PRESSURE OVER THE AREA WILL PROVIDE YET ONE MORE COOL DAY WITH
SUNNY SKIES AND LIGHT WINDS. OTHERWISE IT IS A QUIET SHORT TERM
PERIOD WITH SOME MID LEVEL CLOUDS ARRIVING LATE THIS AFTERNOON.
TEMPERATURES WILL BE ABOUT 10 DEGREES BELOW NORMAL. DECENT WARM AIR
ADVECTION MAY PUSH SOME PRECIPITATION INTO FAR WESTERN MN TONIGHT.
AT THIS POINT IT LOOKS TO BE MOSTLY SNOW AND ANY PRECIPITATION THAT
FALLS WILL BE QUITE LIGHT. FURTHER EAST...LIMITED LIFT AND A VERY
DRY AIR MASS WILL KEEP THE AREA PRECIP FREE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 425 AM CDT FRI MAR 27 2015

NOT A GREAT DEAL OF CHANGE IN THE EXTENDED FORECAST WITH A
GRADUAL WARMING TREND STILL EXPECTED OVER THE NEXT SEVERAL DAYS.
THE MOST NOTABLE WEATHER DISTURBANCE IN THE COMING DAYS IS
EXPECTED ON SUNDAY WHEN A SHARP SHORTWAVE TROUGH SWINGS THROUGH
THE UPPER MISSISSIPPI RIVER VALLEY. THIS WILL LIKELY BRING LIGHT
RAIN TO THE FORECAST AREA AND STRONG WINDS.

AFTER 14 STRAIGHT DAYS WITH HIGHS IN THE 40S/50S/60S/70S IN MID
MARCH...WE HAVE NOW HAD A WEEK STRAIGHT OF HIGHS IN THE 30S FOR
MOST LOCATIONS. THIS STREAK WILL COME TO AN END ON SATURDAY. WE
WILL FINALLY SEE BUILDING HEIGHTS AS A RIDGING SLOWLY MOVES FROM
THE WESTERN CONUS AND HIGH PLAINS TO THE UPPER MISSISSIPPI RIVER
VALLEY. WE MIGHT END UP A BIT WARMER THAN WHAT WE ARE CURRENTLY
FORECASTING ON SATURDAY GIVEN THE DRY FORECAST SOUNDINGS AND GOOD
CHANCE FOR SUNSHINE. SATURDAY COULD END UP NEAR OR IN THE LOWER
50S IF THE SURFACE WINDS END UP MORE S-SW RATHER THAN S-SE.

THE MAIN PRECIP EVENT ON SUNDAY IS IN RESPONSE TO A FORMIDABLE
WAVE THAT PASSES ACROSS NORTHERN MN AND SOUTHERN CANADA. SOUTHERN
MN AND WEST CENTRAL WI STILL REMAINS JUST A BIT TOO FAR SOUTH TO
BE CONCERNED WITH A LOT OF QPF...BUT THERE SHOULD BE A BAND OF
LIGHT RAIN/SNOW /MAINLY RAIN/ TRAILING S-SE NEAR THE COLD FRONT.
ANY PRECIP THAT FALLS ON SUNDAY SHOULD BE PRIMARILY RAIN GIVEN THE
FORECAST SOUNDINGS AND LOW-LEVEL THICKNESSES. THE BIGGER WEATHER
STORY ON SUNDAY WILL LIKELY BE THE STRONG WINDS...FIRST OUT OF THE
SOUTH AND THEN OUT OF THE W-NW BEHIND THE COLD FRONT SUNDAY
AFTERNOON. THE FORECAST SOUNDINGS SHOW CLOSE TO 50KTS AT THE TOP
OF THE BOUNDARY LAYER. EVEN WITH MODEST MIXING WE SHOULD BE ABLE
TO ACHIEVE GUSTS BETWEEN 40 TO 50 MPH. THE ONE CAVEAT WITH THIS
SYSTEM IS THE TIMING DIFFERENCES BETWEEN THE NAM/GFS CAMP AND THE
ECMWF CAMP...WITH THE ECMWF BEING ABOUT 6 HOURS SLOWER WITH THE
COLD FRONTAL PASSAGE. THE ECMWF IS ALSO MUCH LIGHTER WITH THE
WINDS. INTERESTINGLY...WHEN LOOKING AT THE PAST 3-4 MODEL
CYCLES...EACH MODELING SYSTEM HAS HAD GOOD RUN-TO-RUN CONSISTENCY
WITH. NEITHER THE GFS AND ECMWF HAS DEVIATED MUCH IN THE FRONTAL
TIMING.

THE WARM-UP EARLY NEXT WEEK WILL BRING A BIT MORE ATMOSPHERIC MOISTURE
TO THE AREA...PARTICULARLY SOUTHERN MN. THE 5-6 DAY FORECAST OFF
THE GFS WOULD HAVE DEWPOINTS WELL INTO THE 50S...500-1000 J/KG OF
SBCAPE AND MOST LIKELY THUNDERSTORMS ACROSS FAR SOUTHERN MN NEXT
WEDNESDAY. THIS IS AN ENCOURAGING SIGN FOR THUNDERSTORM FANS. THE
ECMWF KEEPS THE JUICE FARTHER SOUTH AT THIS POINT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 109 PM CDT FRI MAR 27 2015

VFR CONDITIONS WITH LIGHT WINDS. HIGH PRESSURE WILL KEEP WINDS
LIGHT AND VARIABLE THIS AFTERNOON. EXPECT A SOUTH SOUTHEASTERLY
DIRECTION LATER TONIGHT...WITH GUSTS NEAR 15KTS LATE SATURDAY
MORNING.

KMSP...NO NOTABLE DIFFERENCES FROM GENERAL DISCUSSION.

/OUTLOOK FOR KMSP/
SAT NIGHT...MVFR WITH -RA/-SN POSSIBLE LATE. WINDS S AT 10G15
KTS.
SUN...VFR. MORNING PRECIP ENDING WITH CLEARING SKIES. WINDS NW AT
25G35KTS.
MON...MVFR PSBL...WINDS WEST 5-10KTS.

&&

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

$$

SHORT TERM...DRL
LONG TERM...CLF
AVIATION...JRB



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