Hail in Wisconsin, September 26, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1119 PM CDT FRI SEP 26 2008

.DISCUSSION...

VERY WARM THERMAL WEDGE AHEAD OF COLD FRONT HAS YIELDED TEMPS IN
THE UPPER 80S IN SW INTO WC MN WITH MID 80S ACROSS MUCH OF THE
REMAINDER OF THE CWA.  CONVECTIVE TEMPS ACROSS SOUTHERN MINNESOTA
ARE IN THE MID 90S...SO AIRMASS STILL CAPPED.  ACTIVITY THUS FAR HAS
BEEN MAINLY POSTFRONTAL ACROSS N MN AHEAD OF SHORTWAVE NOW MOVING
INTO NW MN...BUT STRONGER STORMS LIFTING INTO ONTARIO.  EXPECT THAT
WITH UPSTREAM TROF MOVING IN ADDITIONAL STORMS WILL DEVELOP IN
CENTRAL MN LATE AFTERNOON AND EVENING AND THEN DEVELOP SOUTHWARD AS
MID LEVELS COOL AND CAP WEAKENS.  STILL SOME PRETTY STRONG 0-6KM
SHEAR VICINITY FRONT WHICH COULD BRING A SEVERE THREAT INTO THE
EVENING HOURS. UPPER TROF EXITS E CWA SATURDAY MORNING SO WILL
MAINTAIN CHANCE POPS WC WI INTO SC MN.  WITH COOL 500 MB TEMPS
EXPECT SCATTERED TO PERHAPS BROKEN CU TOMORROW...MAINLY E HALF AREA

HIGH PRESSURE BUILDS ACROSS AREA SATURDAY NIGHT WITH MAINLY MID TO
UPPER 40S EXPECTED.  SOME DIFFERENCES IN MODELS HANDLING OF COLD
FRONT FOR LATE SUNDAY WITH NAM MUCH MORE AGGRESSIVE THAN ECMWF AND
GFS AND THUS QPF OUTPUT HIGHER WITH STRONGER UPPER TROF BACKING MID
LEVEL WINDS LEADING TO BETTER UPGLIDE.  ALL MODELS DO POINT TO
CHANCE TYPE TSTMS MOVING THRU AREA AS MID LEVELS DO SHOW
CONSIDERABLE DESTABALIZATION.

BEHIND SUNDAY NIGHT COLD FRONT UPPER FLOW BECOMES MUCH MORE
AMPLIFIED WITH STRONG RIDGING ACROSS W U.S. AND TROF TO THE EAST
SETTING US UP FOR SOME MORE FALL-LIKE TEMPERATURES. SIGNIFICANT
DIFFERENCES BETWEEN GFS AND ECMWF MID/LATE WEEK WITH ECMWF SHOWING
500 MB HEIGHTS 150 TO 200 METERS HIGHER THAN GFS AND HENCE NOT
CHILLY.  TRENDED TOWARD HPC GUIDANCE FOR NOW...BUT NOT A LOT OF
CERTAINTY IN TEMPERATURES WITH ECWMF ALMOST 20C WARMER AT 850 MB IN
NW MN 12Z FRIDAY.

&&

.AVIATION.../06Z TAF ISSUANCE/

SFC FRONTAL SYSTEM SLOWLY SHIFTING ESE ACROSS CTRL MN AND WRN WI
OVERNIGHT. UPPER WAVE COMING IN FROM THE DAKOTAS HELPING TO ALLOW
THE ATMOSPHERE TO OVERCOME CAPPING AND PROMOTE MORE SHOWER
DEVELOPMENT IN CTRL MN. A FEW ISOLD LIGHTNING STRIKES SEEN WITH
THIS SHOWER ACTIVITY AND GIVEN THE STEEP LAPSE RATES ALOFT THOSE
SHOULD CONTINUE AS THEY SHIFT EASTWARD. SO HAVE CB MENTIONED AT
TAF SITES BUT COVERAGE OF LIGHTNING THUS FAR AND OTHER DIAGNOSTIC
TRENDS INDICATE NOTHING FURTHER NEEDED IN THE ERN TAF SITES. SFC
WINDS BEHIND THE FRONT HAVE COME UP FROM THE NORTH DUE TO THE
SURFACE PRESSURE RISE RESPONSE. ALSO BEHIND THE FRONT HAVE BEEN
MVFR TO IFR CIGS IN A CORRIDOR OF RESIDUAL LOW LEVEL MOISTURE. THE
00Z NAM SEEMS TO HAVE A GOOD HANDLE ON THIS MOISTURE AREA AND
PROPAGATES IT IMMEDIATELY BEHIND THE FRONT. HAVE MVFR AND IFR CIGS
MENTIONED AT ALL TAF SITES AT TIMES IN THE NEXT 6 TO 9 HOURS. WRN
WI MOST PROBABLE AREA FOR MVFR STRATOCU TO HANG AROUND INTO THE
AFTN. THIS AREA SUSCEPTIBLE FOR LOW CLOUD RE-EXPANSION SAT NIGHT
AS LOW LEVEL RIDGE MOVES ATOP THAT AREA.

&&

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

BAP/MTF

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1125 PM CDT FRI SEP 26 2008

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
271100-
DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS-
BENTON-SHERBURNE-ISANTI-CHISAGO-LAC QUI PARLE-SWIFT-CHIPPEWA-
KANDIYOHI-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON-
YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA-
REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE-WATONWAN-BLUE EARTH-
WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN-POLK-BARRON-RUSK-
ST. CROIX-PIERCE-DUNN-PEPIN-EAU CLAIRE-
1125 PM CDT FRI SEP 26 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN.

.DAY ONE...OVERNIGHT

SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS CENTRAL AND EASTERN
MINNESOTA INTO WEST CENTRAL WISCONSIN OVERNIGHT. A FEW OF THESE
STORMS MAY BE STRONG TO SEVERE WITH PENNY SIZE HAIL AND BRIEF GUSTY
WINDS THE POSSIBLE THREATS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORMS ARE POSSIBLE ACROSS WEST CENTRAL WISCONSIN ON
SATURDAY AS THE COLD FRONT MOVES SLOWLY AWAY FROM THE OUTLOOK
AREA. THUNDERSTORMS WILL BE POSSIBLE AGAIN ACROSS MUCH OF THE
OUTLOOK AREA SUNDAY AFTERNOON AND NIGHT AS A NEW COLD FRONT MOVES
ACROSS THE REGION. ALTHOUGH WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED...A FEW OF THE STORMS DURING THESE PERIODS MAY BE STRONG
WITH SMALL HAIL AND GUSTY WINDS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED OVERNIGHT.