Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 280907
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
407 AM CDT TUE JUL 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT TUE JUL 28 2015

A CONVECTIVE LINE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
TRACK EASTWARD ACROSS THE FORECAST AREA THIS MORNING. WIND GUSTS
TO AROUND 40 MPH AND SMALL ARE POSSIBLE...BUT SEVERE WEATHER IS
UNLIKELY THIS MORNING. THE PRIMARY CONCERN WILL BE THE ARRIVAL
TIMING OF THIS LINE AROUND THE MORNING COMMUTE. GIVEN THE
TORRENTIAL RAINFALL THAT WILL ACCOMPANY IT...A SLOWER COMMUTE WILL
LIKELY BE HAD. DO EXPECT A WEAKENING TREND AS THE LINE SHIFTS
EASTWARD INTO MORE STABLE AIR HOWEVER...SO CONCERNS WILL DECREASE
THROUGHOUT MORNING AS IT SHIFTS EASTWARD.

IN THE WAKE OF THIS LINE...THE NEXT CONCERN WILL BE THE POTENTIAL
FOR AFTERNOON/EVENING REDEVELOPMENT AS THE COLD FRONT /CURRENTLY
OVER THE EASTERN DAKOTAS/ MOVES ACROSS THE AREA. GIVEN THE MORNING
CONVECTION...IT WILL LIKELY TAKE AWHILE TO SEE THE BOUNDARY LAYER
DESTABILIZE...ESPECIALLY GIVEN THE PROGGED H7 TEMPS OF +12 TO
+14C NOSING INTO EAST CENTRAL MN. DID RE-INTRODUCE CHANCE POPS
ACROSS CENTRAL/SOUTH CENTRAL MN AT 21Z...BUT THAT COULD BE A BIT
PREMATURE. ONCE CELLS DO DEVELOP...THEY WILL HAVE THE POTENTIAL TO
BE SEVERE...GIVEN THE STRENGTH OF UPPER LEVEL FORCING AND SHEAR
PROVIDED BY ITS RELATIONSHIP WITH THE SURFACE FRONTAL
BOUNDARY...AND LAPSE RATES IN THE 7-8 C/KM RANGE. LARGE
HAIL/WINDS/HEAVY RAINFALL WILL BE THE MAIN CONCERNS...PRIMARILY
EAST OF AN ALEXANDRIA...TO WILLMAR...TO FAIRMONT LINE.

TEMPS TODAY WILL BE A BIT COOLER GIVEN THE CLOUDS/PRECIP AND
EVENTUAL COLD FRONT. HIGHS WILL TOP OUT IN THE 80-85 DEGREE RANGE.
LOWS TONIGHT WILL PRIMARILY RANGE FROM THE UPPER 50S TO LOWER 60S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 406 AM CDT TUE JUL 28 2015

.LONG TERM...(WEDNESDAY THRU MONDAY)

WED THRU FRI REMAIN DRY AND VERY COMFORTABLE IN TERMS OF HUMIDITY
LEVELS AS TODAYS SYSTEM SCOURS OUT THE HUMID AIR MASS. DEW PTS WILL
FALL BACK INTO THE 50S AND LOWER 60S BY WED. EVEN PAST FRIDAY...DEW
PTS DO NOT RISE BACK INTO THE 70S WITH A PERSISTENT NW FLOW ALOFT
KEEPING MOST OF THE HUMID AIR TO THE SOUTH/SW OF MPX CWA. TWO
FRONTAL BOUNDARIES WILL MOVE ACROSS THE UPPER MIDWEST PAST
WEDNESDAY. THE BEST CHC OF ANY CONCENTRATED AREA OF PRECIPITATION
WILL OCCUR SAT/SUN WITH AN ACTIVE UPPER JET MOVES OVERHEAD.

NEXT WEEK LOOKS TO BE COOLER THAN NORMAL FOR EARLY AUGUST. BOTH THE
EC/GFS HAVE BEEN ADVERTISING A SHARP DROP IN TEMPS BY THE MIDDLE OF
NEXT WEEK AS A VERY ABNORMALLY STRONG UPPER LOW ROTATES ACROSS
HUDSON BAY. THIS SAME UPPER LOW IS THE REMNANTS OF TODAYS STRONG
SYSTEM THAT IS VERY ANOMALOUS BASED ON CLIMATOLOGY FOR LATE
JULY/EARLY AUGUST. THIS SYSTEM IS MORE TYPICAL FOR SEPT THEN MID
SUMMER. THE UPPER LOW WILL BEGIN TO TAP MUCH COOLER AIR FROM
NORTHERN CANADA THIS WEEKEND...AND MOVE IT SOUTHWARD INTO THE UPPER
MIDWEST AND GREAT LAKES REGION BY THE MIDDLE OF NEXT WEEK. THE BULK
OF THE COOLEST AIR WILL SLIDE OFF TO THE EAST BY THE END OF NEXT WEEK
...BUT THIS AIR MASS IS COOL ENOUGH FOR HIGHS ONLY IN THE 60S BY
NEXT WED/THU.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1057 PM CDT MON JUL 27 2015

A LINE OF TSRA ACROSS THE CENTRAL DAKOTAS WILL REACH WESTERN MN
AROUND 09Z...THE TWIN CITIES NEAR 12Z AND KEAU AFTER 15Z. SOME
DEVELOPMENT MAY OCCUR AHEAD OF THIS LINE ALONG A WARM FRONT
LIFTING NORTH ACROSS SOUTHERN MN...SKEWING THE TIME A LITTLE. THE
OVERALL TREND IN THIS PACKAGE WAS TO SLOW DOWN THE ONSET OF THE TEMPO
GROUP BY AN HOUR OR SO. CONFIDENCE IS ALSO LOWERING ON MVFR
CEILINGS/VSBYS IN ADVANCE OF THE LINE WITH CONFIDENCE REMAINING
HIGH ON MVFR OR LOWER CEILINGS/VSBYS FOR A FEW HOURS IN THE WAKE
OF THE SHRA/TSRA. SURFACE WINDS WILL INCREASE EARLY ON TUESDAY AS
THE GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. SE WINDS
AT 15-20KTS GUSTING 25KTS ARE LIKELY. THE FRONT WILL NOT PASS THE
TWIN CITIES UNTIL TUESDAY EVENING WHICH MEANS MORE SHRA/TSRA
DEVELOPMENT IS POSSIBLE TUESDAY AFTERNOON AND EVENING ACROSS
EASTERN MN AND WESTERN WI.

KMSP...THE TIMING OF THE SHRA/TSRA HAS SLOWED A BIT WITH TUESDAY
MORNING LOOKING BEST FOR PERHAPS TWO ROUNDS OF STORMS. AT THIS
POINT...INDICATED THE TEMPO FROM 12Z-15Z...BUT THIS MAY STILL BE
TOO EARLY AND NEED TO BE EXTENDED THROUGH THE MORNING (17Z). MORE
DEVELOPMENT IS POSSIBLE IN THE AFTERNOON AHEAD OF A COLD FRONT
BUT THERE IS QUITE A BIT OF UNCERTAINTY...ESPECIALLY DUE TO HOW
THE MORNING ACTIVITY WORK OUT.

/OUTLOOK FOR KMSP/
WED...VFR. WINDS W AT 20G30KT.
THU...VFR. WINDS W AT 10-15 KT.
FRI...VFR. WINDS W AT 5 KT.


&&

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

$$

SHORT TERM...LS
LONG TERM...JLT
AVIATION...RAH


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