Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 260458 AAB
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1158 PM CDT WED MAR 25 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED MAR 25 2015

SURFACE LOW SLIDING EAST FROM THE ARROWHEAD ACROSS NORTHERN LAKE
SUPERIOR THIS AFTERNOON AND STRONG NORTHWEST WINDS HAVE BEEN
REALIZED IN THE STRONG PRESSURE GRADIENT ACROSS THE AREA. THE WIND
SPEEDS WILL SLOWLY WEAKEN THIS EVENING AS THE GRADIENT SLACKENS AND
THE LOW MOVES FURTHER AWAY. STRONG SUBSIDENCE IS MOVING IN FROM THE
EASTER DAKOTAS AND EXPECT THE CLOUD COVER TO QUICKLY DISSIPATE
DURING THE EVENING INTO THE OVERNIGHT FROM WEST TO EAST. REMOVED ALL
POPS FROM THE FORECAST FOR THE REST OF THE AFTERNOON AND EVENING AS
THE PRECIP WILL BE CONFINED TO THE NORTH OF OUR AREA.

A SURFACE HIGH WILL BE SLIDING SOUTH THROUGH CANADA TOWARD OUR AREA
TOMORROW...AND STRONG COLD AIR ADVECTION WILL CONTINUE AND DESPITE
MORE ABUNDANT SUNSHINE...TEMPS WILL BE HELD BELOW
NORMAL...ESPECIALLY OVER THE PORTION OF THE FORECAST AREA WITH A
CURRENT SNOW PACK OBVIOUSLY.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED MAR 25 2015

THE EXTENDED PERIOD WILL START OUT BLW NORMAL WITH A TEMPORALLY
PERIOD OVER THE WEEKEND WITH ABV NORMAL TEMPS...THEN POSSIBLY
ANOTHER COLDER PATTERN DEVELOPING LATE NEXT WEEK BASED ON THE
OVERALL MEAN PATTERN TRANSITION BACK TO NW FLOW AND THE NORTHERN
JET STREAM SHIFTS SOUTH.

SYNOPTICALLY...ONE MAIN WEATHER SYSTEM WILL AFFECT THE UPPER
MIDWEST OVER THE WEEKEND...WITH A SECONDARY SYSTEM NEAR THE END OF
THE 7 DAY PERIOD.

SATURDAY NIGHT/SUNDAY MORNING A STRONG MID LEVEL SHRTWV WILL
DEEPEN ACROSS THE NORTHERN PLAINS AND MOVE THRU THE UPPER MIDWEST.
MODELS HAVE BEEN TRENDING SLOWER WITH THIS SHRTWV...AND DEEPER
WHICH MAY MEAN THAT THE PRECIPITATION WOULD HOLD OFF UNTIL SUNDAY
MORNING. HAVE ALREADY SLOWED THE CHC/S OF PRECIPITATION UNTIL AFT
MIDNIGHT SATURDAY...BUT THIS MAY BE TOO FAST. THE GFS ENSEMBLE
MEAN OF THE 50H IS SLOWER COMPARED TO THE LATEST DETERMINISTIC
RUNS OF THE GFS/EC 12Z WED.

ONE ISSUE THAT HAS SOME CONCERN IS THE CURRENT SNOW PACK WHICH
MAY CONTRIBUTE TO SLIGHTLY COOLER TEMPS THAN CURRENT MODELS
SUGGEST. NOT EXPECTING ANY ICING PROBLEMS AT THIS TIME ONCE THE
PRECIPITATION DEVELOPS SOMETIME EARLY SUNDAY...BUT SOMETHING TO
CONSIDER AS WE GET CLOSER TO THE WEEKEND. IN ADDITION TO THE CHC/S
OF PRECIPITATION...THE WIND SPD PARAMETERS /GFS/ SUGGEST A HIGH
WIND WARNING IN THE TYPICAL AREAS OF WC/SW MN SUNDAY AFTN. AREA
SOUNDINGS IN WESTERN MN HAVE BOUNDARY LAYER WINDS NEAR 30
KTS...WITH 45-50 KTS JUST ABV THIS BOUNDARY LAYER. IF WE HAVE
SUBSTANTIAL MIXING SUNDAY AFTERNOON...WE WILL SEE SIGNIFICANT
WINDS DEVELOP. THIS IS BASED ON THE DEEPER SOLUTION OF THE GFS
AND STRONGER PRESSURE GRADIENT IN THE LEE OF SUNDAY MORNINGS
WEATHER SYSTEM.

PAST SUNDAY...THE MEAN PATTERN OF THE GFS/EC DIFFER AND
COMPLICATES THE WEATHER SITUATION AS ANOTHER STRONG SHRTWV MOVES
ACROSS THE UPPER MIDWEST. THERE IS ENOUGH CONFIDENCE TO HOLD ONTO
ABV NORMAL TEMPS...BUT PRECIPITATION CHC/S REMAIN PROBLEMATIC DUE
TO THE LOCATION OF THE SFC LOW AND FRONTAL BOUNDARY OF THE EC/GFS.

DEPENDING UPON WHICH MODEL SOLUTION IS MORE ACCURATE NEXT
WEEK...THE END OF NEXT WEEK WILL TRANSITION TO A MUCH COLDER
PATTERN AS THE MEAN NORTHERN JET SHIFTS SOUTH ACROSS THE
PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1158 PM CDT WED MAR 25 2015

STRATUS ACROSS THE EASTERN DAKOTAS AND SOUTHERN/WESTERN MINNESOTA
IS DISSIPATING ON SCHEDULE. VFR/MVFR STRATUS OVER NORTHERN MN AND
WI IS A BIT MORE STUBBORN AND MAY CONTINUE TO HANG ON THROUGH MUCH
OF THE OVERNIGHT HOURS IN THE CYCLONIC FLOW. THIS WOULD IMPACT
PRIMARILY EAU WITH RNH ON THE EDGE. DON/T ANTICIPATE STC AND MSP
BEING IMPACTED AT THIS POINT...BUT WILL CONTINUE TO MONITOR.
DIURNAL CI FORECAST TO DEVELOP LATE THURSDAY MORNING WITH BASES
WELL WITHIN THE VFR RANGE.

KMSP...SKC AT TAF ISSUANCE TIME WITH STRATUS TO THE NORTH AND
EAST. IT DOES NOT APPEAR AS IF THIS WILL MAKE ANOTHER
APPEARANCE...SO KEPT THE PREVIOUS TAF LARGELY INTACT.

/OUTLOOK FOR KMSP/
FRI...VFR. WINDS LGT AND VRB.
SAT...MVFR POSSIBLE WITH CHC -RA/-SN LATE. WINDS S 10-15 KTS.
SUN...VFR. PRECIP DEPARTING EAST IN THE MORNING...SKIES CLEARING
IN THE AFTERNOON. WINDS TURNING NW 20-25G35KTS.

&&

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

$$

SHORT TERM...SPD
LONG TERM...JLT
AVIATION...BORGHOFF


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