Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 020350
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1050 PM CDT MON SEP 1 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 1 2014

ISOLD INSTABILITY SHRA/TSRA WILL OCCUR THRU SUNSET ACROSS WC/SW MN
AS A WEAK SHRTWV MOVES ACROSS THE AREA. LATER TONIGHT A STRONGER
SHRTWV MOVING ACROSS SOUTHERN SD MAY GENERATE A FEW MORE SHRA
ACROSS MAINLY SC/SW MN DURING THE PRE DAWN HRS. HOWEVER...MOISTURE
IS LIMITED SO WILL CONTINUE WITH MOSTLY CLOUDY SKIES AND LET THE
EVENING SHIFT HANDLE ANY ADJUSTMENTS BASED ON COVERAGE IN SD THIS
EVENING. NO OTHER CHGS ON TUESDAY AS SKIES CLR BEHIND THIS
AFOREMENTIONED SHRTWV LATER TONIGHT.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 1 2014

TUESDAY NIGHT-THURSDAY...HIGH PRES WILL BE CENTERED OVER THE
APPALACHIANS AT THE START OF THE PERIOD WITH PRONOUNCED SFC RETURN
SLY FLOW AND ZONAL FLOW ALOFT. SURGING MOISTURE AND WARMER AIR
BEHIND THE HIGH BUT AHEAD OF AN INCOMING LOW PRES SYSTEM WILL AID
INCREASES IN HUMIDITY AND INSTABILITY FOR THE MIDDLE OF THE WEEK.
CLOUDS WILL BE ON THE INCREASE BUT PRECIP COVERAGE WILL BE
SOMEWHAT SPARSE FOR WED DUE TO LACK OF SUPPORT ALOFT AND NO
INFLUENTIAL SFC FEATURES...LEAVING PURE CONVECTION AS THE MODE FOR
PRECIP GENERATION. WILL CARRY CHC POPS FOR MAINLY AFTN
DEVELOPMENT. CHCS INCRS FOR INCREASED COVERAGE AND STRENGTH OF
STORMS WED NIGHT AS SEVERAL SHORTWAVE BUCKLES IN THE ZONAL FLOW
ALOFT CROSS OVER THE REGION...BUT THE LARGER CULPRIT WILL BE A
DIGGING LONGWAVE TROUGH OVER ERN MT INTO THE DAKOTAS. THIS TROUGH
WILL SHOVE A DEVELOPMENT LOW PRES CENTER FROM THE ROCKIES INTO THE
ERN DAKOTAS WED EVE THEN INTO NRN MN EARLY THU MRNG. THIS SYSTEM
WILL DRAG A CDFNT ALONG WITH IT...WHILE LLJ DEVELOPS OVER NE/IA
AND SHIFTS INTO SRN MN. THERE IS SOME DISAGREEMENT AS TO
POTENTIALLY WHERE THE BEST CONVERGENCE IS FOR THE DEVELOPMENT OF
TSTMS...SPECIFICALLY SEVERE WX...WHETHER OVER NRN OR SRN MN AND
WRN WI...BUT ENOUGH INGREDIENTS ARE IN PLACE TO AT LEAST THINK
ABOUT THE POTENTIAL FOR SEVERE WX IN PORTIONS OF THE WFO MPX CWFA
WED NIGHT INTO THU. THE PARENT LOW PRES CENTER SHIFTS OFF INTO
LOWER ONTARIO PROVINCE ALONG WITH THE UPR LVL TROF DURG THE DAY
THU...WHILE THE SFC CDFNT SLOWLY PUSHES INTO THE GREAT LAKES. SOME
LINGERING SHOWERS AND TSTMS ARE POSSIBLE THU INTO THU NIGHT BUT
THE VAST MAJORITY OF THE PRECIP LOOKS TO BE OUT OF THE CWFA BY
THEN. TEMPS WILL GO ON A NOTICEABLE WARMING TREND FOR WED-THU
AHEAD OF THE AFOREMENTIONED CDFNT. HIGHS WILL CLIMB TO THE LOW-MID
80S...ALONG WITH DEWPOINTS RISING TO THE LWR 70S...SPELLING A PAIR
OF EARLY SEPTEMBER WARM AND MUGGY DAYS.

FRIDAY-MONDAY...COOLER DRIER CANADIAN HIGH PRES WILL SLOWLY SLIDE
ESE ACRS THE NRN PLAINS AND UPR MISS RIVER VALLEY FRI-SUN. THIS
WILL RESULT IN MAINLY CLEAR SKIES...OR AT LEAST A MIX OF SUN AND
CLOUDS DURG THE DAYTIME PERIODS...AND NOTICEABLY COOLER
TEMPERATURES THAT WILL MAKE IT FEEL LIKE EARLY SEPTEMBER. HIGHS
WILL BE BUMPED BACK DOWN TO ARND 70 WITH LOWS TO ARND 50.
HOWEVER...MORE UNSETTLED WX LOOKS TO BE THE STORY FOR THE START OF
THE FULL WORK WEEK NEXT WEEK AS HIGH PRES SHIFTS OFF TO THE EAST
AND ANOTHER GULF OF ALASKA LONGWAVE TROF DROPS INTO THE PAC NW
OVER THE WEEKEND...DIGGING INTO THE WRN CONUS EARLY NEXT WEEK.
RETURN FLOW ON THE BACKSIDE OF THE HIGH PRES AREA ON MON COMBINED
WITH A DEVELOPING LOW PRES SYSTEM OVER THE NRN PLAINS IN ADVANCE
OF THE LONGWAVE TROF WILL MAKE FOR A SETUP OF SCATTERED
SHWRS/TSTMS ON MON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1050 PM CDT MON SEP 1 2014

ISOLATED SHOWERS AND THUNDERSTORMS WILL WORK THEIR WAY EASTWARD
ACROSS CENTRAL/SOUTHERN MN AND WEST CENTRAL WI OVERNIGHT AND
TUESDAY MORNING. DUE TO THE NATURE OF THE PRECIPITATION ONLY VCSH
WAS USED. A CONCERN FOR THE OVERNIGHT IS THE POTENTIAL FOR FOG TO
DEVELOP...ESPECIALLY ACROSS WEST CENTRAL WI INCLUDING KRNH AND
KEAU. THE LIMITING FACTOR IS HOW FAST MID/HIGH LEVEL CLOUDINESS
INCREASES AFTER MIDNIGHT. CONFIDENCE IS LOW SO KEPT THE MENTION
OUT FOR NOW. LIGHT WINDS OVERNIGHT WILL INCREASE TO 10-14 KNOTS BY
LATE TUESDAY MORNING FROM THE WSW. WINDS WILL DIMINISH ONCE AGAIN
TUESDAY EVENING.

KMSP...ONLY EXPECT ISOLATED SHRA/TSRA DURING THE OVERNIGHT HOURS
(08Z-12Z) WITH A MORE SOLID AREA OF PRECIPITATION PASSING ACROSS
IA AND FAR SOUTHERN MN. VFR THROUGH THE PERIOD.

/OUTLOOK FOR KMSP/

WED...VFR. CHC MVFR/TSRA. WINDS S 10-15 KTS.
THU...VFR. CHC MVFR/TSRA LATE. WINDS S 10-15 KTS BCMG W LATE.
FRI...VFR. WINDS NW 10 KNOTS.

&&

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

$$

SHORT TERM...JLT
LONG TERM...JPC
AVIATION...RAH






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