Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 100830
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
330 AM CDT THU JUL 10 2014

.SHORT/LONG TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CDT THU JUL 10 2014

WARM AND SUMMER-LIKE WEATHER WITH PERIODS OF SUN AND THUNDERSTORMS
WILL GIVE WAY TO COOL...CLOUDY...AND DOWNRIGHT FALL-LIKE WEATHER FOR
THE BEGINNING OF NEXT WEEK. WARMER AND DRIER WEATHER WILL FOLLOW THE
NEAR RECORD COOL TEMPERATURES.

EARLY MORNING WATER VAPOR WITH 500MB HEIGHTS AND WINDS SHOWED A
SHORTWAVE LOCATED ACROSS WESTERN MONTANA. THIS SHORTWAVE WILL
CONTINUE EASTWARD AND DRAW UP WARM MOIST AIR AHEAD OF IT. STILL SOME
UNCERTAINTY WITH THE TIMING OF THE PRECIP...WHETHER IT WILL BE LATE
THURSDAY NIGHT OR MORE TOWARD FRIDAY MORNING. GIVEN THE CONSISTENCY
OF THE UPPER LEVEL WAVE BEING LOCATED OVER THE MN/WI BORDER BY 06Z
FRIDAY...AND CENTRAL WI BY 12Z...HAVE SPED UP THE TIMING OF THE POPS
EVEN THOUGH THE BEST LOW LEVEL MOISTURE LAGS THIS UPPER LEVEL
FEATURE. THE NAM 10.00 IS THE MOST PROGRESSIVE WITH THE QPF...AND IN
THE PAST HAS DONE BETTER WITH THE TIMING OF WARM AIR ADVECTION
PRECIP. GIVEN THE 925MB MASS FIELDS ARE FAIRLY CONSISTENT BETWEEN
THE GFS/ECMWF/NAM FEEL COMFORTABLE WITH LEANING TOWARDS THE QUICKER
SOLUTION.

ONCE THIS PRECIP EXITS THE REGION BOUNDARY LAYER DESTABILIZATION
WILL OCCUR BEHIND IT ACROSS WESTERN MN...SO REINTRODUCED POPS LATE
FRIDAY AFTERNOON. THE CHANCE OF PRECIP LINGERS THROUGH
SUNDAY...BUT THE HIGHEST PROBABILITY IS ACROSS IOWA WHERE THE
BOUNDARY BECOMES MORE EAST/WEST ORIENTED SETTING THE STAGE FOR
HEAVY RAIN DOWN THERE. HOWEVER...CANT RULE OUT THUNDERSTORMS AT
ANYTIME OVER THE WEEKEND ACROSS MN/WI...SO CONTINUE WITH SLIGHT
CHANCE OF PRECIP ALTHOUGH MOST OF THE PERIOD SHOULD BE DRY.

LOOKING AHEAD...ASIDE FROM THURSDAY NIGHT...THE HIGHEST CONFIDENCE
IN PRECIP WILL BE ON MONDAY AS A POWERFUL UPPER LEVEL WAVE
STRENGTHENS ACROSS CENTRAL CANADA AND DROPS SOUTHWARD ACROSS THE
UPPER MIDWEST. THE GFS/GEM/ECMWF ARE IN REMARKABLE AGREEMENT WITH
THE LOCATION OF THIS PV ANOMALY...AND THE HEIGHTFALLS THAT PRECEDE
IT. COLD AIR ADVECTION WILL KEEP BOUNDARY LAYER LAPSE RATES
STEEP...AND DEEP LOW LEVEL MOISTURE MEANS OVERCAST SKIES AND PERIODS
OF LIGHT RAIN SHOWERS. THIS PATTERN IS SIMILAR TO JULY 17 2009...OR
JULY 27 2013 WHICH SET RECORD LOW MAXIMUM TEMPERATURES OF 65 AND 64
RESPECTIVELY. THEREFORE HEDGED TEMPERATURES CLOSER TO THE
GFS...WHICH HAS HIGHS ONLY IN THE 60S FOR BOTH MONDAY AND TUESDAY.
ALSO INCREASED CLOUD COVER CONSIDERABLY SINCE FORECAST SOUNDINGS
SHOW OVERCAST SKIES FOR BOTH MONDAY AND TUESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM CDT WED JUL 9 2014

HIGH PRESSURE WILL SLIP SOUTHEAST OF THE TAF SITES OVERNIGHT.
LIGHT SE WINDS WILL DEVELOP EARLY THURSDAY MORNING ON THE
BACKSIDE OF THE HIGH AND THEN BECOME MORE SOUTHERLY AT 10 KNOTS
FOR THE AFTERNOON. MOISTURE WILL BE INCREASING AS WELL ON THE
BACKSIDE OF THE HIGH WITH MID LEVEL CEILINGS (080-120) SPREADING
EAST ACROSS CENTRAL AND SOUTHERN MN DURING THE DAY. INSTABILITY
PUSHES INTO WESTERN MN TOWARD EVENING. THIS COUPLED WITH AN
INCREASE IN THE LOW LEVEL WIND FIELD SHOULD AID IN FORMING
SCATTERED SHOWERS AND THUNDERSTORMS FOR KAXN AND KRWF. THIS
ACTIVITY WILL MOVE EAST DURING THE NIGHT AND LIKELY REACH INTO THE
TWIN CITIES BEFORE DAYBREAK FRIDAY AND ACROSS WEST CENTRAL WI
FRIDAY MORNING.

KMSP...VFR CLR-SCT OVERNIGHT AND THURSDAY MORNING. REMAINING VFR
THURSDAY AFTERNOON AND EVENING WITH MID LEVEL CEILINGS (080-120)
DEVELOPING. SCT SHRA/TSRA EXPECTED LATE THURSDAY NIGHT/FRIDAY
MORNING.

/OUTLOOK FOR KMSP/

FRI...VFR WITH MVFR/SHRA/TSRA POSSIBLE. WINDS S 10 KTS.
SAT...VFR. WINDS NW 4-8 KTS.
SUN...VFR WITH MVFR/SHRA/TSRA POSSIBLE. WINDS W 6-10 KTS.

&&

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

$$

SHORT TERM...JRB
LONG TERM...JRB
AVIATION...RAH






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