Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 232039
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
339 PM CDT SAT AUG 23 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 339 PM CDT SAT AUG 23 2014

THE MAIN SHORT TERMS CONCERN IS TIMING OF CONVECTION AND SEVERE
WEATHER THREAT TONIGHT INTO SUNDAY...AND THE EXCESSIVE HEAT THREAT
FOR SUNDAY AFTERNOON/EVENING.

LIGHT SHOWERS LIFTING NORTHEAST ASSOCIATED WITH INITIAL UPPER WAVE
LIFTING OVER THE NORTHEAST CWA. REMNANTS OF THE MCS STILL RIDING
EAST OVER SOUTHWEST WISCONSIN AND MAY CONTINUE SMALL THREAT OF
THUNDER OVER WEST CENTRAL WISCONSIN THIS EVENING.  MODELS HAVE
SLOWED MAIN SHOT OF CONVECTION ASSOCIATED WITH THE UPPER TROUGH
OVERNIGHT.  APPEARS CONVECTION FIRING NOW OVER CENTRAL SOUTH DAKOTA
NOW. THIS SI FORECAST TO MOVE INTO WESTERN MN MAINLY AFTER 03Z.
SOME QUESTION AS TOO HOW FAR EAST TO TAKE THE THUNDER. IT APPEARS
EAST CENTRAL MN WILL BY ON THE EDGE OF THIS THREAT AS MAINLY
TROUGH/FORCING LIFTS OVER THE NORTHWEST CWA.  WITH PW`S AROUND
2 INCHES...SOME HEAVY RAIN LIKELY...ESPECIALLY WEST CENTRAL
OVERNIGHT.  THE FRONT MOVES INTO WESTERN MN DURING THE MORNING
SUNDAY...AND WILL CONTINUE CHANCE POPS WITH THE FRONT MOVING INTO
CENTRAL MN BY AFTERNOON.  SEVERE THREAT FOR THE LATE AFTERNOON
REMAINS AS WELL...MAINLY FROM CENTRAL AND NORTHERN MN WITH BETTER
DEEP LAYER SHEAR EXPECTED.

NEXT PROBLEM WILL BE EXCESSIVE HEAT THREAT FOR SUNDAY AFTERNOON.
CURRENTLY CONTINUE THE TREND OF TEMPERATURES WARMING TO AROUND 90
OVER THE EASTERN HALF OF THE CWA.  WITH DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE FORECAST TO RISE TO 95 TO 100 FOR A FEW
HOURS IN THE AFTERNOON/EVENING.  CONSIDERED AND ADVISORY FOR THE
METRO...BUT THE CLOUD COVER TRENDS REMAIN TRICKY AGAIN INTO SUNDAY
AFTERNOON. WE SHOULD SEE CLOUDS CLEAR THROUGH THE LATE
MORNING...WITH MORE SUNSHINE EXPECTED.  CONFIDENCE IS LOW ENOUGH
WITH MARGINAL CRITERIA NOT TO ISSUE AT THIS TIME. WILL HAVE ONE MORE
MODEL RUN TO SEE IF CLOUDS CLEAR MORE QUICKLY IN THE MORNING.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 339 PM CDT SAT AUG 23 2014

SHOWERS AND THUNDERSTORMS WILL LIKELY PUSH ACROSS THE EASTERN
PART OF THE FORECAST AREA ON SUNDAY NIGHT AS THE FRONT SWEEPS
ACROSS EASTERN MINNESOTA AND WISCONSIN. PRECIPITABLE WATER VALUES
SOAR TO AROUND 180 PERCENT OF NORMAL /1.8 INCHES/...WITH 1 TO 2 INCH
RAINFALL AMOUNTS THEREFORE APPEARING POSSIBLE EAST OF THE
INTERSTATE 35 CORRIDOR.

FOR MONDAY...THE FRONT APPEARS TO SHIFT FAR ENOUGH SOUTH AND EAST
OF THE AREA TO LIMIT PRECIPITATION CHANCES. HAVE REMOVED POPS FOR
MONDAY. HOWEVER...THE FRONTAL BOUNDARY WILL STALL JUST SOUTH OF
THE AREA THROUGH MID WEEK AS MULTIPLE MID LEVEL SHORTWAVES
OVERRIDE THE BOUNDARY. THIS WILL FACILITATE LIKELY PRECIP CHANCES
FROM MONDAY NIGHT INTO AT LEAST WEDNESDAY ACROSS SOUTHERN
MINNESOTA...TAPERING OFF TO 20-30 PERCENT CHANCES NORTHWARD TO THE
TWIN CITIES AND EAU CLAIRE. THE 23.12Z ECMWF AND GEM CONTINUED TO
SLOW THE EXIT OF THE TROUGH/BOUNDARY...WHERE AS THE GFS BLASTS PRECIP OUT
OF THE AREA BY THURSDAY. THINK THE GFS IS A BIT TOO QUICK...AT LEAST FOR
SOUTHERN/EASTERN AREAS...SO HAVE INCLUDED SHOWER AND THUNDERSTORM
CHANCES ON THURSDAY FOR SOUTH/EAST CENTRAL MN AND WEST CENTRAL WI.
WHILE PRECIP CHANCES WILL NEED NOTABLE REFINEMENT WITH FUTURE
MODEL RUNS...COOLER THAN NORMAL TEMPS ARE MORE OF A GIVEN...WITH
HIGHS FROM TUESDAY THROUGH FRIDAY RANGING FROM THE UPPER 60S TO
MID 70S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1212 PM CDT SAT AUG 23 2014

NORTHERN EDGE OF DISSIPATING MCS OVER EASTERN IOWA CLIPPED KMSP
AROUND NOON. LIGHT -SHRA INDICATED. THIS CONTINUES TO MOVE EAST
AND IF MAY AFFECT KEAU EARLY. INCLUDED VCSH FOR THAT. COMPLICATED
SCENARIO DEVELOPING WITH THE UPPER TROUGH MOVING THROUGH THE
DAKOTAS. HIRES MODELS ARE PICKING UP ON SOME ACCAS LIFITNG OUT OF
SOUTHEAST SODAK. THEY DEVELOP SOME ISOLD TSRA INTO SW MN DURING
THE AFTERNOON...AND DISSIPATE LATE AFTERNOON INTO SC MN. WONT
MENTION THIS ACTIVITY AT TAF SITE FOR NOW. LOWER IFR CLOUDS REMAIN
LOCKED OVER CENTRAL MN WITH SOME EROSION NOTED INTO SC MN. THIS
MAY WORK N-NE INTO THE AFTERNOON IN THE WAKE OF THE IOWA MCS. WILL
TREND VFR THROUGH ABOUT 00Z MOST AREAS. EXPECT THUNDER TO DEVELOP
AROUND 00Z IN EASTERN SODAK AND LIT NORTHEAST OVER WESTERN AND
CENTRAL MN THROUGH THE NIGHT. HEAVY RAIN/POSSIBLE SEVERE INTO FAR
WESTERN MN THROUGH ABOUT 06Z OR SO. WILL DROP CIGS AGAIN TO IFR
OVERNIGHT AS WARM FRONT LIFTS OVER THE AREA. WILL MENTION MAINLY
3-5SM BR WITH IFR CIGS. EXPECT SLOW IMPROVEMENT AGAIN INTO
SATURDAY MORNING...SIMILAR TO PREVIOUS FORECAST TREND. INCREASING
GRADIENT AHEAD OF FRONT SHOULD YIELD SOME STRONG SE-S SOUTH WINDS
WITH FROPA SATURDAY.

KMSP...-SHRA/SPINKLES EXITING KMSP NOW. NEXT THREAT MOVES IN AFTER
05Z WITH A PROB30 FOR THUNDER INDICATED THROUGH 08Z. CIGS EXPECTED
TO DROP OFF TO IFR LATE WITH IMPROVING CONDITIONS TO MVFR BY
MIDE/LATE SUNDAY MORNING. EAST TO SOUTHEAST WINDS AHEAD OF WARM
FRONT...WITH WINDS BECOMING MORE SOUTHERLY BY LATE SUNDAY MORNING
OR EARLY SUNDAY AFTERNOON. SPEEDS AREA EXPECTED TO REMAIN AROUND
10KTS INTO TONIGHT...INCREASING TO 10-14KTS SUNDAY MORNING.

/OUTLOOK FOR KMSP/
SUN NIGHT...VFR. CHANCE MVFR/TSRA. S WINDS 10-14KTS BCMG W 5-10
KTS.
MON...VFR. WINDS W 5-10 KTS.
TUE...SHRA/TSRA AND MVFR LIKELY BY AFTERNOON. WINDS NE 5-10 KTS.


&&

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

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...DWE






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