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000
FXUS63 KMPX 182047
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
347 PM CDT FRI JUL 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI JUL 18 2014

THINGS LOOK TO REMAIN REASONABLY QUIET THROUGH THE SHORT TERM...
ALTHOUGH WE WILL FINALLY BE BRINGING MOISTURE AND INSTABILITY INTO
THE REGION... SO IT WILL LIKELY BE THE LAST SUCH SHORT TERM PERIOD.
LATEST VISIBLE IMAGERY SHOWS SCATTERED CU ACROSS THE AREA ONCE
AGAIN TODAY... UNDER A CANOPY OF LINGERING SMOKE AND SOME SCATTERED
AC. SURFACE ANALYSIS SHOWS A COLD FRONT OVER THE NORTHERN PLAINS...
AND THIS FEATURE WILL TRY TO COME AT US LATE TONIGHT AND SATURDAY...
BUT WILL MISERABLY FAIL IN THAT ATTEMPT. SHRA/TSRA SHOULD DEVELOP
ALONG/AHEAD OF THE FRONT THIS AFTERNOON/EVENING WHERE THERE IS A
NICE RIBBON OF 1000-2000 J/KG MLCAPE AND DECENT FORCING ASSOCIATED
WITH A SHORTWAVE NORTH OF THE CANADIAN BORDER, A SECOND FEATURE CAN
BE SEEN MOVING THROUGH SOUTH DAKOTA AT THE CURRENT TIME... BUT IT
APPEARS THAT IT WILL OUTPACE THE LOW LEVEL FORCING AND
INSTABILITY... AND SHOULDN/T DO MUCH IF ANYTHING AS A RESULT.
HOWEVER... STORMS WHICH DO FORM OVER THE DAKOTAS WILL TRACK EAST AND
ATTEMPT TO WORK INTO OUR AREA OVERNIGHT TONIGHT. BUT... GIVEN THE
DRY AIR CURRENTLY IN PLACE AND CAPPING EVIDENT ON OUR 12Z
SOUNDING... THIS INITIAL ATTEMPT SHOULD LARGELY FAIL AND MAINLY JUST
SERVE TO REDUCE THAT CAP A BIT WHILE MOISTENING UP THE PROFILE SOME.
DID BRING SOME CHANCE POPS INTO THE FAR WEST/NORTHWEST TONIGHT...
BUT DRIED THEM OUT QUICKLY AS THEY TRY TO SHIFT EAST. THE CAM
SOLUTIONS... INCLUDING THE HOPWRF... SPCNMM... AND HIRES WINDOWS...
ALL SHOW A SIMILAR WEAKENING EVOLUTION WITH THIS ACTIVITY AS WELL.
ON SATURDAY... WHAT/S LEFT OF THE COLD FRONT WILL MOVE ACROSS THE
AREA... BUT BY LATE IN THE DAY THERE WILL BE LITTLE TO KNOW
BAROCLINIC OR FORCING ASSOCIATED WITH IT. SOME KINEMATIC FORCING
FROM A LINGERING WIND SHIFT WILL REMAIN... AND THAT COULD BE
SUFFICIENT TO KICK OFF ISOLATED/SCATTERED SHRA/TSRA OVER THE CENTRAL
AND EASTERN PART OF THE AREA BY LATER SATURDAY AFTERNOON INTO
SATURDAY EVENING. SO... ALLOWED FOR SOME POPS TO REDEVELOP ACROSS
THAT PORTION OF THE AREA DURING THE AFTERNOON.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 345 PM
CDT FRI JUL 18 2014

HOT AND HUMID CONDITIONS WILL DEVELOP ACROSS THE MIDWEST AS AN UPPER
LEVEL RIDGE BUILDS OVER THE 4 CORNERS REGION. DIABATIC HEATING
ALONG THE FOOTHILLS OF THE ROCKIES WILL DEVELOP A SEASONABLY HOT
AIRMASS...AND THIS AIRMASS WILL OVERSPREAD THE UPPER MIDWEST. H850
TEMPERATURES OF 20 TO 25C WILL SUPPORT SURFACE TEMPERATURES IN THE
LOW TO MID 90S ACROSS THE DAKOTAS AND WESTERN MN SUNDAY. THIS HEAT
WILL SHIFT EASTWARD ON MONDAY...AS DEWPOINTS CLIMB INTO THE MID 70S.
AS ALLUDED TO IN THE PREVIOUS FORECAST DISCUSSION...CONVECTIVE
DEBRIS WILL BE THE LIMITING FACTOR ON TEMPERATURES...BUT AS OF NOW
EXPECT HEAT INDICES TO BE IN THE 100 TO 110F RANGE BY MID AFTERNOON.

SPEAKING OF CONVECTION...CONFIDENCE IS LOW IN ANY PRECIP BEFORE
MONDAY EVENING. THE MLCAPE MAX OFF THE GFS/NAM IS CENTERED ACROSS
MN/WI...WHICH IMPLIES THAT THE REGION WILL BE CAPPED OFF IN ORDER TO
GENERATE THAT AMOUNT OF INSTABILITY. FORECAST SOUNDINGS SUPPORT THIS
HYPOTHESIS. IN ADDITION...THERE IS ACTUALLY LOW LEVEL DIVERGENCE AT
H850...SO DESPITE THE THETA_E ADVECTION AND 30-40KT LOW LEVEL JET
FEEL THAT THE CAP WILL HOLD AND MOST OF THE CWA WILL STAY DRY.

BY MONDAY NIGHT ALL THE NUMERICAL MODELS BRING A SHORTWAVE CURRENTLY
LOCATED OFF THE SOUTHERN CALIFORNIA SHORE OVER THE 500MB RIDGE AND
ACROSS THE UPPER MIDWEST. GIVEN THE THERMODYNAMICALLY RICH
ENVIRONMENT WITH CHARACTERIZED BY 4000-5000J/KG OF MUCAPE...AND
PWATS IN EXCESS OF 2IN...THE NUMERICAL MODELS VIGOROUSLY DEVELOP
PRECIP THROUGH THE DAY ON TUESDAY. THERE APPEARS TO BE SOME
CONVECTIVE FEEDBACK WITH THIS SYSTEM...AND AT THIS TIME FEEL THE
HIGHEST CHANCE FOR PRECIP WILL BE NORTH OF I94 TIED TO THE UPPER
LEVEL FORCING. IF STORMS DO MANAGE TO DEVELOP THEY COULD PROPAGATE
SOUTHEASTWARD. THE HIGHEST RISK APPEARS TO BE HEAVY RAIN SINCE BOTH
MEAN WIND AND SHEAR WILL BE LIGHT WITHIN THE COLUMN. LOOKING
AHEAD...COOLER AND DRIER AIR WILL BRING MORE SEASONABLE CONDITIONS
FOR THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1200 PM CDT FRI JUL 18 2014

THINGS STILL LOOK GENERALLY QUIET THROUGH THE FORECAST PERIOD...
ALTHOUGH SLIGHTLY MORE COMPLICATED THAN THE PAST FEW DAYS. FRONTAL
BOUNDARY OVER THE DAKOTAS WILL MOVE EAST THROUGH THE FORECAST AS
ITS ASSOCIATED UPPER LEVEL TROUGH MOVES EAST ACROSS SOUTHERN
CANADA. THE FRONT WILL LOSE ITS IDENTITY AND WASH OUT AS IT
CROSSES MINNESOTA LATE TONIGHT AND SUNDAY. CONVECTION IS EXPECTED
TO FIRE OVER THE DAKOTAS ALONG THE BOUNDARY LATER TODAY... AND
THIS WILL MOVE TOWARD THE AREA TONIGHT. HOWEVER... THE ACTIVITY
WILL LIKELY OUTPACE THE INSTABILITY GRADIENT AND FORCING WILL BE ON
THE DECREASE AS THE FRONT LOSES BAROCLINITY AND THE UPPER WAVE
STAYS WELL TO THE NORTH. SO... ALTHOUGH SOME SHRA/TSRA COULD MAKE
IT INTO THE WESTERN PART OF THE AREA... DO NOT EXPECT MUCH TO HOLD
TOGETHER AS IT MOVES EAST. KEPT PCPN OUT OF ALL TAFS EXCEPT KAXN
GIVEN THESE EXPECTATIONS. WHAT/S LEFT OF THE OLD BOUNDARY WILL
BE NEAR OR A BIT EAST OF I-35 BY SATURDAY AFTERNOON... AND THERE/S
A POSSIBILITY FOR SOME ISO/SCT SHRA/TSRA TO DEVELOP ALONG IT.
HOWEVER... CONFIDENCE IN OCCURRENCE... TIMING... AND LOCATION IS
PRETTY LOW... SO CHOSE NOT TO INCLUDE ANYTHING FOR THE EASTERN
SITES AT THIS POINT.

KMSP...MAIN AREA OF CONCERN IS WHETHER ANY SHRA/TSRA WILL IMPACT
THE AREA... WITH THE TIME FRAME OF POTENTIAL LOOKING TO BE FROM
AROUND 19-22Z SATURDAY. HOWEVER... CONFIDENCE IN OCCURRENCE IS
LOW... WITH THE POSSIBILITY OF EITHER NOTHING DEVELOPING AND/OR IT
OCCURRING EAST OF THE AREA. SO... CHOSE TO LEAVE PCPN OUT OF THE
FORECAST... AND KEEP VFR THROUGHOUT. SOME GUSTS AOA 20KT FROM THE
SOUTH ARE EXPECTED THIS AFTERNOON AS THE GRADIENT TIGHTENS AND WE
MIX MORE DEEPLY.

/OUTLOOK FOR KMSP/
SATURDAY NIGHT. BRIEF MVFR POSSIBLE WITH A CHANCE OF SHRA/TSRA.
SOUTH WIND 5 TO 15 KT.
SUNDAY THROUGH MONDAY. VFR. SOUTH WIND 5 TO 15 KT.
MONDAY NIGHT AND TUESDAY. MVFR POSSIBLE WITH A CHANCE OF
SHRA/TSRA. SOUTH WIND 5 TO 15 KT BECOMING LIGHT AND VARIABLE
TUESDAY.


&&

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

$$

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