Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 050354
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1054 PM CDT MON MAY 4 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 350 PM CDT MON MAY 4 2015

HIGH PRES ATOP THE AREA TDA HAS SUPPRESSED CLOUD COVER...ALLOWING
FOR PLENTY OF SUNSHINE BEHIND THE CDFNT FROM YDA WHICH HAS STALLED
OUT OVER THE MID-MISS RIVER VALLEY AND CENTRAL PLAINS REGIONS.
DESPITE PLENTY OF SUNSHINE...CAA AS EVIDENCED BY NLY WINDS ALL DAY
LONG HAS KEPT HIGHS IN THE MID 60S TO LWR 70S. CLOUDS WILL INCRS
TNGT AS THE HIGH PRES CENTER SHIFTS OFF TO THE E AND THE STALLED
FRONT GAINS IMPETUS TO LIFT N AS A WMFNT TNGT THRU TUE. HOWEVER...
PER OVERALL MODEL TREND FROM LAST NIGHT THRU TDA...THIS NWD
PROGRESSION WILL BE SLOWER AND THIS WILL INFLUENCE THE TIMING OF
THE RETURN OF SHWRS/TSTMS INTO SRN MN TUE. IN ADDITION...A NW-SE
ORIENTED UPR LVL RIDGE AXIS WILL SHIFT NNE ACRS THE AREA DURG THE
DAY TUE...AND THIS RIDGE WILL ALSO KEEP THE WMFNT ALONG WITH ANY
ASSOCIATED PRECIPITATION OFF TO THE S. THEREFORE...HAVE BEEN ABLE
TO KEEP THE FCST DRY UNTIL THE PRE-DAWN HRS EARLY TUE MRNG THEN
KEPT THE PRECIP ONLY IN FAR SRN AND SWRN PORTIONS OF MN TUE. HAVE
ALSO KEPT POPS NO HIGHER THAN LOW-CHC RANGE DUE TO THE SLOWER
PROGRESSION...AND ALSO CONFINED TSTM MENTION TO TUE WITH NO TSTM
MENTION FOR TNGT. TEMPS LOOK TO RUN FAIRLY SIMILAR TMRW AS WHAT
WAS RECORDED TDA...WITH HIGHS IN THE UPR 60S TO ARND 70...DUE TO
NO APPRECIABLE TEMP ADVECTION. LOWS TNGT WILL RANGE FROM ARND 40
IN NRN PORTIONS OF THE WFO MPX CWFA TO ARND 50 NEAR THE IA BORDER.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 350 PM CDT MON MAY 4 2015

THE EXTENDED PERIOD CAN BE CHARACTERIZED AS UNSETTLED/MORE HUMID
AND AN ANOMALOUS FEED OF DEEP MOISTURE FROM THE GULF THROUGH THE
WEEKEND. TWO FRONTS ARE FORECAST TO MOVE ACROSS THE UPPER MIDWEST
WHICH WILL FOCUS A MUCH BETTER CHANCE OF ORGANIZED CONVECTION...
HEAVY RAINFALL AND ASSOCIATED HIGHER CONFIDENCE OF LIKELY OR
CATEGORICAL POPS. HOWEVER...AS MOISTURE BEGINS TO SURGE NORTHWARD
TUESDAY...ANY PERIOD IN THE EXTENDED HAS A CHANCE OF RAINFALL.
BASICALLY WE NEED TO FOCUS ON FRONTAL PASSAGES WHICH WILL INCREASE
THE LIKELIHOOD OF RAINFALL.

AS FOR FRONTAL PASSAGES...THE FIRST WILL OCCUR THURSDAY...WITH A
SECOND FRONT LATE IN THE WEEKEND. BOTH OF THESE FRONTS AND
ASSOCIATED MOISTURE/ENERGY PARAMETERS HAVE THE POTENTIAL OF SEVERE
THUNDERSTORMS. HOWEVER...THE OVERALL DEEP WIND SHEAR PARAMETERS
ARE NOT STRONG ENOUGH TO WARRANT ANYTHING OTHER THAN SLIGHT
CHC/S.

THE UPPER AIR PATTERN REMAINS FAVORABLE FOR COPIOUS AMOUNTS OF
DEEP GULF MOISTURE TO PROGRESS NORTHWARD ACROSS THE PLAINS AND
INTO THE UPPER MIDWEST. PWATS ANOMALIES ARE NEARLY 2-3 STANDARD
DEVIATIONS ABV NORMAL FOR THIS TIME OF YEAR BY THURSDAY WITH
VALUES NEAR 1.30" TO 1.50". THE MOISTURE ADVECTION PARAMETERS BLW
70H ARE OVER THE TOP WITH STANDARD DEVIATIONS AS HIGH AS 4-5 ABV
NORMAL IN THE UPPER MIDWEST BY THURSDAY...LEADING TO A HIGHER
PROBABILITY OF HEAVIER RAINFALL TOTALS ONCE CONVECTION DEVELOPS.
THE MAIN DILEMMA IS WHERE DOES THE PRECIPITATION BEGIN OR FOCUS AS
THE WEEK PROGRESSES. THERE IS A HINT OF A STRONG LLJ FOR TUESDAY
NIGHT INTO WEDNESDAY MORNING...BUT THIS FOCUS IS MAINLY IN WESTERN
AND NORTHERN MN. NOT UNTIL THURSDAY AS THE FRONT MOVES THROUGH
MN/WI DOES ANY TYPE OF A HIGHER PROBABILITY OF HEAVY
RAINFALL/THUNDERSTORMS AND SEVERE WEATHER DEVELOPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1054 PM CDT MON MAY 4 2015

VFR THROUGH THE PERIOD. SHRA/TSRA TO REMAIN SOUTH OF THE TAF
SITES THROUGH TUESDAY MORNING AS A DRY ENE LOW LEVEL FLOW
PREVAILS. THE LOW LEVEL FLOW WILL VEER TO A MORE SE DIRECTION
TUESDAY AFTERNOON...ALLOWING FOR CEILINGS OF 040-050 TO SPREAD
SLOWLY NORTH ACROSS THE TAF SITES. SMALL CHANCES FOR SHRA AT KRWF
TUESDAY AFTERNOON/EVE WITH DRY WEATHER CONTINUING ELSEWHERE. SE
WINDS WILL BE ON THE INCREASE BY LATE TUESDAY MORNING WITH 12-16
KNOTS SUSTAINED WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON.

KMSP...FEW CONCERNS THIS CYCLE. ESE WINDS INCREASING TUESDAY
MORNING TO 12-14 KNOTS WITH GUSTS 20 KNOTS THROUGH THE AFTERNOON.
CEILINGS OF 040-050 DEVELOPING TUESDAY EVENING.

/OUTLOOK FOR KMSP/
WED...VFR. CHC MVFR CONDS IN SHRA/TSRA. WINDS SE 10-20 KTS.
THU...MVFR CONDS LIKELY WITH IFR CONDS POSSIBLE IN SHRA/TSRA.
      WINDS S 10-20 KTS.
FRI...VFR. WINDS NW 5-10 KTS.

&&

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

$$

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


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