000
FXUS63 KMPX 191123
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
623 AM 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 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 610 AM CDT WED JUN 19 2013

VFR CIRRUS AND ISOLATED MID LEVEL DECK OVER WESTERN HALF OF
TAF SITES SHORTLY AFTER 12Z. LOOK FOR THIS LAYER TO OVERSPREAD
REMAINDER OF REGION BY ABOUT 15Z. PROXIMITY OF WARM FRONTAL
BOUNDARY SHOULD BE CATALYST FOR WDLY SCT CONVECTION OVER MOST
AIRPORT SITES BY MID TO LATE AFTN. LIGHT SE FLOW BECOMES MDT
WITH MIXING BY 15Z ACROSS SOUTHERN MN/WESTERN WI. MUCH BETTER
CHANCE FOR CONVECTION KICKS OFF KAXN AND KRWF AFT 07Z...AND
OVER REMAINDER OF TAF AREA BY 10Z...AS LOW LEVEL FORCING AND
JET STREAM SUPPORT INCREASES MARKEDLY. VFR CIGS AND VSBYS
ANTICIPATED PRIOR TO OVERNIGHT CONVECTIVE ACTIVITY...WITH
OCNL MVFR CIGS/VSBYS AS ACTIVITY WITHIN VCNTY OR OVERHEAD.


KMSP...

/OUTLOOK FOR KMSP/

VFR CIGS AND VSBYS THROUGH MOST OF TAF PERIOD...WITH LIGHT
OCNL MODERATE SE FLOW EXPECTED. SLIGHT CHANCE FOR STRONG
T-STORMS ANTICIPATED AFTER 10Z TONIGHT...IN TANDEM WITH LOW LEVEL
SOUTHERLY JET STREAM. POSSIBILITY OF SHORT TERM LLWS 20/06Z-20/12Z
TIME FRAME. MVFR CIGS AND VSBYS WILL BE VERY POSSIBLE ASSOCIATED
WITH CONVECTION LATE. COULD BE VCSH AT KMSP UNTIL 20/20Z...UNTIL
FORCING DIMINISHES.

THU...VFR. CHC OF MVFR. TSRA LIKELY. SSE WINDS 10 KTS.
FRI...VFR. CHC OF MVFR. TSRA LIKELY FRI NIGHT. S WINDS 10-15 KTS.
SAT...VFR. CHC OF MVFR TSRA. S WINDS 5-12 KTS.
SUN...VFR. CHC OF MVFR TSRA. S-SW WINDS 5-12KT.

&&

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

$$

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