Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 211720
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1220 PM CDT MON APR 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT MON APR 21 2014

MAIN CONCERN IN THE SHORT TERM IS THE CONVECTION CURRENTLY OCCURRING
ACROSS THE AREA... AND HOW IT WILL EVOLVE THROUGH THE MORNING HOURS.
LATEST SURFACE ANALYSIS SHOWS A TIGHT DEWPOINT GRADIENT FROM WEST
CENTRAL MINNESOTA THROUGH WEST CENTRAL WISCONSIN... ACTING AS A WARM
FRONT OF SORTS... WITH THE THERMAL GRADIENT A BIT FARTHER NORTH AND
ALSO TO THE WEST ALONG THE SURFACE TROUGH. SPC MESOANALYSIS MUCAPE
SHOWS VALUES OF 250-500 J/KG COINCIDENT WITH THE AREA OF ACTIVITY
CURRENTLY OVER THE AREA... LINING UP FAIRLY WELL WITH THE RAP
ANALYZED 850MB THETA-E RIDGE AHEAD OF THE SURFACE FRONT AND
SHORTWAVE APPARENT IN WATER VAPOR IMAGERY. THINGS ARE EXPECTED TO
CONTINUE TO SHIFT EAST THIS MORNING... WITH MOST OF THE ACTIVITY
EAST OF THE FORECAST AREA AFTER 15Z. HOWEVER... UNTIL THAT TIME WE
WILL SEE SOME LOCAL DOWNPOURS AND PEA-SIZED HAIL WITH THE STORMS
THAT ARE MOVING THROUGH THE AREA. BY 18Z WE SHOULD SEE CLEARING
QUICKLY WORKING ITS WAY FROM WEST TO EAST ACROSS THE FORECAST
AREA... WITH STRONG NORTHWEST WINDS... PARTICULARLY OVER WEST
CENTRAL AND SOUTH CENTRAL MINNESOTA. THE COMBINATION OF STRONG WINDS
AND RELATIVE HUMIDITY VALUES IN THE 20S THIS AFTERNOON WILL RESULT
IN ELEVATED FIRE DANGER POTENTIAL FOR FROM WEST CENTRAL INTO SOUTH
CENTRAL MINNESOTA... SO WILL CONTINUE THE FIRE WEATHER WATCH FOR
THAT AREA. HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT... WITH
WINDS QUICKLY DYING OFF DURING THE EVENING HOURS... AND COOLER
TEMPERATURES MOVING BACK INTO THE AREA... MAKING FOR LOWS IN THE 30S
AND PERHAPS BELOW FREEZING IN OUTLYING AREA.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT MON APR 21 2014

TRENDS IN THE LONG TERM CONTINUE TO INDICATE A FAIRLY ACTIVE
MIDWEEK...FOLLOWED BY A COOLING TRNED THAT WILL LAST THROUGH NEXT
WEEKEND.

HIGH PRESSURE BEGINS THE LONG TERM FOR TUESDAY. IT SHOULD BE A
RATHER PLEASNT DAY WITH LIGHT WINDS...AND MILD TEMPERATURES.

THE NEXT WESTERN CONUS TROUGH DIGS SOUTHEAST AND BEGINS TO AFFECT
THE AREA LATE TUESDAY NIGHT. RETURN FLOW AND LLJ INTENSIFIES
OVER THE EASTERN DAKOTAS LATE TUESDAY NIGHT. THIS WILL DEVELOP AT
LEAST SOME WIDELY SCATTERED CONVECTION IN THE EASTERN
DAKOTAS...SPILLING EAST INTO WEST CENTRAL MN LATE. STEEPER LAPSE
RATES MOVE INTO THE WEST DURING THE DAY WEDNESDAY...WITH THE
THREAT OF ISOLATED CONVECTION EXPECTED. THE MORNING ACTIVITY WILL
SPREAD EAST INTO WESTERN WISCONSIN WITH REDEVELOPMENT AGAIN TO THE
WEST INTO THE AFTERNOON. THE BETTER INSTABILITY WORKS EAST WITH
TROUGH WEDNESDAY NIGHT INTO THURSDAY.  AREA OF STEEP LAPSE RATES
LIFT NORTH ACROSS AT LEAST THE SOUTHERN HALF OF THE AREA AHEAD OF
THE SURFACE LOW WHICH IS PROGGED TO MOVE SOUTH OF THE CWA...ALONG/NEAR
THE MN/IA BORDER. STILL SEE SOME ELEVATED HAIL POSSIBILITIES LATER
WEDNESDAY NIGHT AND THURSDAY MORNING.

MODEL DISCREPANCIES REMAIN AS TO HOW QUICKLY THE UPPER LOW MOVES
EAST OF THE AREA. THE 00Z ECMWF IS MOST PROGRESSIVE WITH THE SYSTEM
AND DROPS SOME COLDER AIR SOUTH OVER THE AREA INTO THE WEEKEND.
THE 00Z GFS IS SLOWER AND MUCH MORE AMPLIFIED WITH THE SYSTEM. IT
EVENTUALLY DROPS 85H TEMPERATURES CLOSE TO MINUS 12C ONCE AGAIN BY
SATURDAY MORNING. THIS MAY BE OVERDONE...BUT IT DOES APPEAR WELL
BELOW NORMAL TEMPERATURES ARE ONCE AGAIN IN STORE WELL INTO THE
WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1220 PM CDT MON APR 21 2014

NORTHWEST WINDS HAVE INCREASED IN THE WAKE OF A COLD FRONT WITH
SPEEDS OF 15-20 KNOTS LIKELY THROUGH THE AFTERNOON ALONG WITH
GUSTS IN THE 25-30 KNOT RANGE. THE STRONGEST WINDS WILL BE FROM
KAXN ON SOUTH THROUGH KRWF. MVFR CEILINGS HAVE BEEN APPROACHING
KAXN FROM THE NORTHWEST...BUT THE LEADING EDGE IS SHOWING SIGNS OF
ERODING. PLAN ON JUST KEEPING A SCT DECK FOR THE AFTERNOON. THE
NORTHWEST WINDS WILL DIMINISH THIS EVENING WITH A SLOW VEERING TO
THE NORTH - NORTHEAST FOR TUESDAY.

KMSP...VFR FOR THE NEXT 30 HOURS. NORTHWEST WINDS THIS AFTERNOON
NEAR 20 KNOTS WITH GUSTS REACHING THE UPPER 20 KNOT RANGE. SPEEDS
WILL DIMINISH RATHER QUICKLY AFTER SUNSET. NORTH WINDS 6 TO 8
KNOTS ON TUESDAY.

/OUTLOOK FOR KMSP/

TUE AFTN...VFR. N WIND 6-8 KTS.
TUE NGT...VFR. WIND BCMG SE 6-8 KTS.
WED...MAINLY VFR WITH MVFR CIGS/VSBYS POSSIBLE ALONG WITH -RA.
SE WIND 10-20 KTS.
WED NGT...MVFR CIGS/VSBYS LIKELY IN -RA WITH IFR POSSIBLE.
SE WIND 15 TO 20 KTS.
THU...MVFR CIGS/VSBYS LIKELY EARLY WITH -RA. S WIND 10-20 KTS
SHIFTING W.
THU NGT...VFR. WEST WIND 5 TO 15 KT.
FRI...MVFR CIGS/VSBYS POSSIBLE WITH A CHANCE OF -RA. W WIND 5-15
KTS BCMG NW.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR MNZ047-054>056-
     064-065-073>075-082-083-091-092.

WI...NONE.
&&

$$

SHORT TERM...TRH
LONG TERM...DWE
AVIATION...RAH






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