Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 171940
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
240 PM CDT THU JUL 17 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 231 PM CDT THU JUL 17 2014

ANOTHER BENIGN SHORT TERM PERIOD WILL UNFOLD TONIGHT AND FRIDAY.
UPPER WAVE THAT BROUGHT FLOODING RAINS TO NORTH TX LAST NIGHT WILL
MOVE INTO THE OHIO VALLEY THIS PERIOD. AS THIS HAPPENS...OUR FLOW
ALOFT WILL TURN MORE WRLY AS A STRONG SHORT WAVE WORKS OUT INTO THE
CANADIAN PRAIRIES. THIS CANADIAN UPPER WAVE WILL HELP DRIVE A COLD
FRONT ACROSS THE DAKOTAS TOMORROW...WHICH WILL RESULT IN THE ONLY
NOTICEABLE CHANGE IN THE WEATHER FRIDAY...STRONGER SOUTHERLY WINDS
IN RESPONSE TO THE TIGHTENING OF THE PRESSURE GRADIENT BETWEEN THE
DAKOTAS FRONT AND THE SPRAWLING ERN CONUS SFC HIGH...WHICH WILL HAVE
GONE FROM THE OHIO VALLEY TODAY OVER TO THE EAST COAST FRIDAY.

AS WE HAVE SEEN SINCE THE COLD DAY ON MONDAY...EVERY DAY SINCE THEN
HAS BEEN WARMER THAN THE DAY BEFORE AND THIS WILL CONTINUE TO BE THE
CASE FRIDAY...WITH HIGHS CONTINUING TO CREEP UP INTO THE UPPER
70S/LOWER 80S. WILL ALSO SEE WARMER CONDITIONS TONIGHT THAN WHAT WAS
SEEN LAST NIGHT...ESPECIALLY IN WRN MN...WHERE THE BOUNDARY LAYER IS
NOT EXPECTED TO DECOUPLE...WHICH WILL HELP KEEP LOWS UP IN THE 60S.
CONSIDERING WE SAW VERY LITTLE IF ANY FOG LAST NIGHT...WITH LOWS
EXPECTED TO BE A FEW DEGREES WARMER TONIGHT...THAT WILL KEEP FOG
FROM BEING ANY SORT OF AN ISSUE. FINALLY...NAM CU RULE CONTINUES TO
BE NEGATIVE FOR FRIDAY...WHICH MEANS WE WILL ONCE AGAIN SEE A CU
FIELD DEVELOP AFTER 10 AM FRIDAY MORNING...MUCH LIKE THE LAST TWO
DAYS. THE ONLY DIFFERENCE IS THAT HIGHER SFC DEWPOINTS WILL RESULT
IN LOWER LCLS...WHICH MEANS THE CU WILL COME IN BETWEEN 4K AND 6K
FEET AS OPPOSED TO 5K AND 7K FEET LIKE WE HAVE SEEN THE LAST COUPLE
OF DAYS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 231 PM CDT THU JUL 17 2014

THE LONGER TERM WILL FINALLY BRING SOME CHANCES OF PCPN INTO THE
AREA... ALTHOUGH OVERALL THINGS APPEAR FAIRLY QUIET IN TERMS OF
ANY OBVIOUS SIGNIFICANT WEATHER CONCERNS. FAIRLY ZONAL FLOW AT THE
START OF THE PERIOD LOOKS TO GIVE WAY TO A BROAD UPPER RIDGE
ACROSS MOST OF THE CONUS BY TUESDAY... WITH TROUGHING OFF THE WEST
COAST. HOWEVER... BY THE END OF THE WEEK IT APPEARS WE SHOULD SEE
THE RIDGE FLATTEN AS A PIECE OF THE WESTERN TROUGH CRESTS THE
RIDGE AND DROPS INTO THE UPPER MIDWEST AND GREAT LAKES. THE ECMWF
AND GFS ARE ACTUALLY IN GOOD AGREEMENT ON THE OVERALL LARGE SCALE
PATTERN... WITH THE EXPECTED DIFFERENCES IN TIMING AND AMPLITUDE
OF INDIVIDUAL SHORTWAVE FEATURES OVER THE COURSE OF THE WEEK. IN
GENERAL TERMS... THIS ALL LEADS TO A WARMING TREND ACROSS THE
REGION INTO MONDAY/TUESDAY... THEN A BIT OF A COOL DOWN BY
WEDNESDAY/THURSDAY. A MORE SIGNIFICANT COOL DOWN BACK TO
NEAR/BELOW NORMAL TEMPERATURES COULD THEN OCCUR BY THE WEEKEND...
BUT WE/LL HAVE TO WAIT AND SEE IF THAT SUGGESTION IN THE GUIDANCE
PERSISTS. A SHORTWAVE MOVING BY TO OUR NORTH FRIDAY NIGHT INTO
SATURDAY WILL TRY TO PUSH A COLD FRONT THROUGH THE AREA.
HOWEVER... THAT FEATURE LOOKS TO LOSE ITS BAROCLINITY AND WASH OUT
AS IT MAKES THE ATTEMPT. THE MAIN FORCING AND CHANCE TO SEE ANY
PCPN LATE FRIDAY INTO SATURDAY WILL BE ACROSS THE NORTHERN PORTION
OF THE AREA... SO INCLUDED SOME CHANCE POPS FOR THAT POSSIBILITY.
ANOTHER SHORTWAVE AND FRONT WILL MAKE A RUN AT THE AREA LATE
TUESDAY... AND THAT LOOKS TO HAVE A BETTER CHANCE AT BRINGING PCPN
TO THE AREA. IN BETWEEN THEN WE COULD SEE SOME SHRA/TSRA MONDAY IF
A TRANSIENT FEATURE IS ABLE TO TRIGGER CONVECTION AS ROBUST
INSTABILITY SITS OVER THE AREA AND THE PERIPHERY OF THE RIDGE
LOITERS OVER US. SOME CHANCE POPS LOOK NECESSARY TOWARD THE TAIL
END OF THE FORECAST AS WE START TO SEE THE RIDGE FLATTEN AHEAD OF
THE APPROACHING PACIFIC NORTHWEST TROUGH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1250 PM CDT THU JUL 17 2014

QUIET WEATHER CONTINUES...WITH THE ONLY CHANGE BEING THE SLOW
EWRD PROGRESSION OF THE SFC HIGH FROM THE OHIO VALLEY TOWARD THE
EAST COAST. AS THIS IS HAPPENING...A COLD FRONT WILL MOVE INTO THE
DAKOTAS. THIS WILL RESULT IN A TIGHTENING OF THE PRESSURE GRADIENT
AND A RESULTANT INCREASE IN SRLY WINDS LATE FRIDAY MORNING. ALSO
EXPECT THE CU FIELD TO ACT SIMILARLY THIS PERIOD...WITH IT
DISAPPEARING BETWEEN 0Z AND 2Z...ONLY TO REAPPEAR AFTER 16Z FRIDAY
MORNING. HOWEVER...INCREASED DEWPOINTS FRIDAY AS COMPARED TO TODAY
WILL RESULT IN SAID CU FIELD SETTING UP IN MORE THE 4K-6K FT RANGE
AS OPPOSED TO THE 5K-7K FT RANGE.

KMSP...NO ISSUES EXPECTED THIS TAF PERIOD...WITH TAF REFLECTING
EXPECTATIONS WITH HIGH CONFIDENCE.

/OUTLOOK FOR KMSP/
SAT-MON...VFR. WINDS S/SW 5-15KTS.


&&

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

$$

SHORT TERM...MPG
LONG TERM...
AVIATION...MPG







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