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000
FXUS63 KMPX 191757
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1257 PM CDT WED JUN 19 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT WED JUN 19 2013

CIRRUS SHIELD NOTED ON IR SATELLITE ENTERING FAR WESTERN MN.
SHIELD IS JUST AHEAD OF DEEPENING SURFACE CYCLONE ABOVE EASTERN
MONTANA. THIS FEATURE WILL BE EJECTED OUT OF 50H TROF OVER PACIFIC
NW DURING THE NEXT 24 HOURS INTO WESTERN NODAK AND SOUTHERN
SASKATCHEWAN. WARM FRONTAL BOUNDARY ATTACHED TO SURFACE CYCLONE
WILL BE CATALYST FOR SCATTERED SHOWERS AND ISOLATE THUNDERSTORMS
LATE THIS MORNING OVER FAR WESTERN CWA. USED GFS40 THETA E
ADVECTION AND HRRR GUIDANCE FOR PLACEMENT AND TIMING OF DAYTIME
CONVECTION OVER FA. COULD BE A FEW STRONG TO NEAR SEVERE
THUNDERSTORMS THIS AFTERNOON OVER CENTRAL AND PORTIONS OF SW MN
TO...AS JOULES INCREASE INTO THE 1500 TO 2500 RANGE. MODERATE
250MB DIVERGENCE COUPLETS ALSO NOTED OVER THESE AREAS ALONG WITH
LI`S PLUNGING INTO THE NEGATIVE 4 TO NEGATIVE 8 CATEGORY. ONLY
LIMITING FACTOR WOULD BE THICKER CLOUD DECK THEN CURRENT CIRRUS
SHIELD PROGGED FOR MUCH OF THE DAYTIME HOURS.

PRESENCE AND PROGRESSION OF WARM FRONTAL BOUNDARY DEEPER INTO
SOUTHERN HALF OF MN TONIGHT SHOULD PORTEND SLIGHTLY ENHANCED
CHANCES FOR CONVECTION...WITH QPF VALUES ALSO RISING NOTICEABLY.
COULD BE A QUICK QUARTER INCH TO ONE HALF INCH OF MOISTURE
GENERATE FROM CONTINUE SCT ACTIVITY DURING THE OVERNIGHT. 850MB
LAPSE RATES AND LI`S WILL ALSO RISE SLIGHTLY OVERNIGHT. MODERATE
SOUTHERLY LOW LEVEL JET WILL ALSO FORM BY LATE TONIGHT OVER MUCH
OF MN FA ...WITH 25 TO 30KT MAGNITUDES COMMON SOUTH OF A LINE FROM
ALEXANDRIA TO OWATONNA. COULD BE ADDITIONAL ISOLATED STRONG TO
NEAR SEVERE T-STORMS OVER WESTERN HALF OF FA DURING THE
EVENING...SWITCHING TO FAR EAST CENTRAL MN/WEST CENTRAL WI AFTER
MIDNIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 410 AM CDT WED JUN 19 2013

WARM AND MOISTURE-RICH PATTERN WILL REMAIN IN PLACE FOR THE END OF
THIS WEEK INTO THE START OF NEXT WEEK...INCLUDING PERIODS OF
STRONG THUNDERSTORMS AND HEAVY RAIN. AN UPPER LEVEL RIDGE BUILDING
OVER THE DAKOTAS AND MN/WI THRU TDA WILL SHIFT TO THE E THRU THU
WHILE A LONGWAVE TROUGH DEVELOPS OVER THE NORTHWEST. SEVERAL
SHORTWAVE DISTURBANCES RIDING NOT ONLY OVER TOP THE RIDGE BUT ALSO
AROUND THE BASE OF THE TROUGH THU INTO FRI WILL WORK WITH AN
INCOMING SFC FRONTAL SYSTEM DEVELOPING OVER THE CENTRAL-NRN
PLAINS. SOLID SW FLOW WILL BRING NOT ONLY WARMER AIR /WHICH WILL
RAISE H5 HEIGHTS TO ENHANCE CAPPING BUT ALSO STRONGER JETTING/ BUT
ALSO MOISTURE-RICH AIR /HELPING RAISE PWATS ABOVE 1.50 INCHES AND
ENHANCE INSTABILITY/...AND THE SFC FRONTAL WAVES COMBINED WITH
UPPER LEVEL DISTURBANCES WILL ALLOW FOR PERIODS OF CONVECTION.
THURSDAY CONTINUES TO BE HIGHLIGHTED BY SPC INVOF THE APCHG CDFNT
FOR THE WRN HALF OF MN. ONCE THE CAPPING INVERSION IS LOST OVER
WRN MN...STRONG MID- AND UPPER-LEVEL JETTING WITH STEEP LAPSE
RATES WITHIN A HIGHLY UNSTABLE ENVIRON /INCLUDING DEWPOINTS NEAR-
OVER 70 DEGREES/ WILL PROMOTE STRONG TO SEVERE TSTMS CAPABLE OF
PRODUCING LARGE HAIL AND DMGG WINDS. THE REGIME THEN TRANSITIONS
TO ONE OF HEAVY RAIN OVER THE WEEKEND AS THE SFC LOW PRES SYSTEM
OPENS UP AND BECOMES CAUGHT UP IN THE PROLIFIC SWLY FLOW WHILE THE
NW UPPER LEVEL TROUGH OPENS TO MORE OF A TROUGH THAN CUTOFF LOW.
LONG PLUME OF SLY SFC FLOW WILL AID IN BRINGING MOISTURE WELL N
INTO THE UPPER MISS RIVER VALLEY REGION. MODEL QPF CONTINUES TO
ADVERTISE BETWEEN 3 AND 6 INCHES OF RAIN FOR THE AREA THROUGH THE
WEEKEND...BUT WITH MUCH OF IT CONVECTIVE...TRYING TO PINPOINT
WHERE SUCH RAINFALL EVENTS MAY OCCUR IS HIGHLY PROBLEMATIC.
STILL...HAVE KEPT HIGH-END CHC POPS GOING IN THE FCST. POPS
DIMINISH FOR THE START OF NEXT WEEK AS A MORE ZONAL UPPER LEVEL
PATTERN DEVELOPS...KEEPING ANY ORGANIZED LOW PRES SYSTEMS AWAY
FROM THE AREA. THAT SAID...SEVERAL MID- AND UPPER-LEVEL SHORTWAVE
DISTURBANCES WILL STILL BE CAPABLE OF PRODUCING ISOLD TO SCATTERED
CONVECTION AS THE WARM/MOIST AIR WILL REMAIN IN PLACE THROUGH
EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1250 PM CDT WED JUN 19 2013

THE CU FIELD IS EXPANDING ACROSS THE MN RIVER VALLEY AND A FEW
SHOWERS/TSTMS COULD OCCUR THIS AFTERNOON IN THIS AREA AS TEMPS
PEAK IN THE UPPER 80S. A FEW ELEVATED SHOWERS/TSTMS MAY ALSO
OCCUR IN WEST CENTRAL WI AS MID LEVEL INSTABILITY MOVES THROUGH.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THE
EVENING FOR KAXN AND KRWF WITH SHOWERS AND ISOLATED THUNDERSTORMS
MOVING INTO THE TWIN CITIES AND WEST CENTRAL WI DURING THE
OVERNIGHT HOURS. THE ACTIVITY WILL LINGER OVER EASTERN AREAS
THURSDAY MORNING. THERE IS NO REAL FOCUS ON THE SHOWERS AND
THUNDERSTORMS TONIGHT/EARLY THURSDAY AND MUCH WILL RELY ON THE
DEVELOPMENT OVER THE DAKOTAS LATER THIS AFTERNOON AND TONIGHT. A
MUCH BETTER CHANCE FOR STRONG TO SEVERE STORMS WILL EXIST THURSDAY
AFTERNOON AND NIGHT ACROSS WESTERN AND SOUTHERN MN AS A FRONTAL
BOUNDARY INCHES CLOSER TO THE AREA. LOOK FOR SE WINDS FROM 10 TO
15 KNOTS THIS AFTERNOON WITH SOME GUSTS TO AROUND 20 FOR KAXN AND
KRWF.

KMSP...VFR EXPECTED THROUGH THE PERIOD. THE BEST CHANCE FOR
SHOWERS AND ISOLATED THUNDERSTORMS IS FROM LATE TONIGHT THROUGH
THURSDAY MORNING. TEMPORARY DIPS TO MVFR CAN BE EXPECTED IN THE
BOUTS OF PRECIPITATION. SE WINDS THIS AFTERNOON AND TONIGHT NEAR
10 KNOTS.

/OUTLOOK FOR KMSP/

THU NIGHT...VFR. CHC OF MVFR/TSRA. SE WINDS 10 KTS.
FRI...VFR. CHC OF MVFR/TSRA. SE WINDS 10 KTS.
SAT...VFR. CHC OF MVFR/TSRA. SE WINDS 8 KTS.
SUN...VFR. CHC OF MVFR/TSRA. S WINDS 10 KTS.

&&

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

$$

SHORT TERM...AJZ
LONG TERM...JPC
AVIATION...RAH