Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 271745
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1245 PM CDT MON JUL 27 2015

.UPDATED FOR 18Z AVIATION...
ISSUED AT 1231 PM CDT MON JUL 27 2015

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 27 2015

ANOTHER HOT AND MUGGY DAY IS AHEAD...AS TEMPERATURES MODERATE TO
BETWEEN 85 AND 90 DEGREES. HEAT INDICES WILL RANGE FROM 90 TO 95
DEGREES AT THEIR AFTERNOON MAX VALUES...ALTHOUGH INCREASING WINDS
AND SCATTERED CLOUD COVER SHOULD HELP MINIMIZE HEAT CONCERNS BELOW
ADVISORY THRESHOLDS. WILL SEE H7 TEMPS WARM TO AROUND +12C INTO
CENTRAL MN THIS AFTERNOON...SO GIVEN THAT AND THE ABSENCE OF ANY
FORCING...HAVE REMOVED POPS FOR THE AFTERNOON HOURS.

BY THIS EVENING /00Z TUESDAY/...MODELS INDICATE STRONG H85
MOISTURE TRANSPORT WILL ENSUE FROM THE EASTERN DAKOTAS INTO
SOUTHWEST MN AS LOW LEVEL WINDS INCREASE AHEAD OF THE ADVANCING
TROUGH. IT SEEMS TO TAKE AWHILE FOR EASTWARD EXPANSION OF MOISTURE
ADVECTION/CONVERGENCE TO OCCUR...SO HAVE DELAYED THE EASTWARD
PROGRESSION OF THUNDERSTORM CHANCES A BIT. DO NOT THINK WE WILL
SEE CONVECTION REACH THE MN/WI BORDER UNTIL AROUND 09Z TUESDAY.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 27 2015

THERE IS A POTENTIAL OF A VERY ACTIVE TUESDAY AFTN IF TUESDAY
MORNING CONVECTION EXIT MINNESOTA AND THE REGION CAN RECOVER AHEAD
OF A COLD FRONT.

FIRST...IT LOOKS VERY PROMISING THAT MONDAY NIGHTS CONVECTION WILL
CONTINUE TO AFFECT MOST OF MN TUESDAY MORNING. STRONG ASCENT AHEAD
OF THE SHARP UPPER LOW AND VERY STRONG MOISTURE ADVECTION /CURRENT
ANOMALY OF 85/70H MOISTURE ADVECTION IS 4-6 STANDARD DEVIATIONS ABV
NORMAL FOR THIS TIME OF YEAR FOR THE UPPER MIDWEST/ SHOULD LEAD TO A
LARGE AND WIDESPREAD AREA OF SHRA/TSRA MOVING ACROSS MN DURING THE
MORNING. HOW FAR EAST THIS AREA OF SHRA/TSRA MOVES REMAINS THE MAIN
DILEMMA FOR RECOVERY AS THE COLD FRONT MOVES ACROSS MN. MODELS HAVE
BEEN FAIRLY CONSISTENT ON THE FRONTAL POSITION BISECTING THE STATE
AROUND NOON ON TUE. THE AMT OF WIND ENERGY WITH THIS SYSTEM AND IF
MODERATE INSTABILITY CAN BE ACHIEVED...AN EXPLOSIVE ATMOSPHERE IN
TERMS OF SVR WX IS POSSIBLE EAST OF THIS FRONT. ONE OF THE CIPS
ANALOGS IS JUNE 17 2010 WHERE MN HAD ITS BIGGEST OUTBREAK OF
TORNADOES. AN AVERAGE OF THE TOP 15 ANALOGS HAS 60/70% OF AT LEAST
ONE SVR WX REPORT IN SOUTHERN MN TUE AFTN. THERE IS EVEN A 20/30%
CHC OF 10 SVR WX REPORTS BASED ON THESE 15 TOP ANALOGS ON THE
CURRENT MODEL RUN 27/00Z. AGAIN...THIS IS HIGHLY BASED ON TUESDAY
AFTN RECOVERY AHEAD OF THE COLD FRONT WHICH IS CURRENTLY FORECAST TO
BE IN EASTERN MN TUESDAY AFTN. ANOTHER ASPECT TO THIS SYSTEM IS THE
POTENTIAL OF EXCESSIVE RAINFALL...ESPECIALLY WITH PWATS ARND 1.75"
TO 2.00". IF ANY TRAINING OF THE TSRA DEVELOPS THERE COULD BE A
THREAT OF FLASH FLOODING. WITH THESE TYPE OF PWAT VALUES...RAINFALL
RATES WILL AVERAGE 1-2 INCHES PER HR.

ANY TSRA/SHRA ACTIVITY TUESDAY EVENING SHOULD QUICKLY MOVE OUT OF
MPX CWA BY 6Z...WITH A DRY PERIOD EXPECTED AT LEAST THRU FRIDAY.
THIS SHARP COLD FRONT WILL SCOUR OUT OUR OPPRESSIVE DEW PTS IN THE
70S...WITH 50S LIKELY FOR WED/THU.

BY NEXT WEEKEND...ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE
UPPER MIDWEST. WITH THE JET STREAM NEARLY OVERHEAD...AND SOME RETURN
FLOW WITH DEW PTS RISING BACK INTO THE 60S...ANOTHER CHC OF SVR WX
IS POSSIBLE SAT/SUN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1231 PM CDT MON JUL 27 2015

TIMING OF CONVECTION REMAINS ON TRACK FOR LATE TONIGHT...SO DID
NOT MAKE SIGNIFICANT CHANGES TO THE PREVIOUS TAF. MORNING CLOUDS
SHOULD CONTINUE TO BURN OFF BY EARLY AFTERNOON. STORMS SHOULD LIFT
UP FROM THE SOUTHWEST AS THE WARM FRONT MOVES ACROSS THE REGION
TONIGHT. THIS SHOULD EVENTUALLY DEVELOP INTO A NORTH/SOUTH
ORIENTED LINE THAT WILL MOVE EASTWARD ACROSS THE REGION WITHIN THE
10-14Z TIMEFRAME.

KMSP...
THE WARM FRONT CONVECTION IN THE 06-08Z TIMEFRAME SHOULD BE
SOUTHWEST OF KMSP...AND THE MAIN THREAT FOR CONVECTION WILL BE
WITH A NORTH/SOUTH ORIENTED LINE THAT WILL AFFECT THE METRO
AROUND 12Z TUESDAY MORNING. LOW CLOUDS WILL LIKELY DEVELOP IN THE
WAKE OF THIS LINE. COULD SEE SOME THUNDERSTORM REDEVELOPMENT IN
THE AFTERNOON...BUT THIS SHOULD BE EAST OF KMSP. WESTERLY WINDS
WILL DEVELOP LATE TUESDAY EVENING AS THE COLD FRONT PASSES
THROUGH.

/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...JRB


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