Hail and Damaging Winds in Minnesota, September 15, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
143 AM CDT WED SEP 15 2010

.DISCUSSION...

A COMPLEX OF SHRA/TSRA HAS DEVELOPED ACROSS EASTERN SD EARLY THIS
MORNING ALONG WITH SOME FRISKY TSRA THAT PRODUCED QUARTER SIZE
HAIL NEAR WATERTOWN SD ARND MIDNIGHT. REGIONAL VWP INDICATED THAT
WNDS WERE BEGINNING TO VEER TO THE S/SE ACROSS IA/SE SD AND SW MN.
E/SE WNDS WERE ACROSS E/SE MN WHICH INDICATED THAT STRONG
CONVERGENCE WAS DEVELOPING ACROSS WC AND SW MN. ALTHOUGH ELEVATED
CONVECTION WILL LIKELY CONTINUE TO DEVELOP NORTH/NE ACROSS CENTRAL
MN...BELIEVE THE MAIN ACTIVITY WILL LIKELY HOLD NEAR THE MN RIVER
VALLEY...NORTH TO I-94. THIS IS JUST SLIGHTLY FURTHER NORTH THAN
PREVIOUS MODELS INDICATED A FEW RUNS AGO. HOWEVER...OVERALL THE
MODELS CONTINUED TO ADVERTISE TWO WAVES OF SIGNIFICANT
PRECIPITATION MOVING ACROSS SOUTHERN/CENTRAL MN...AS WELL AS WEST
CENTRAL WISCONSIN THROUGH WEDNESDAY EVENING.

QPF AMTS WILL LIKELY BE ALTERED SLIGHTLY NORTH THEN PREVIOUSLY
INDICATED. HOWEVER...THIS IS BASED ON MODEL INTERPRETATION AND
SHORT TERM ANALYSIS REMAINS MORE FAVORABLE FOR AREAS ALONG THE MN
RIVER VALLEY. USING REGIONAL PROFILERS AND VWP WILL HOLD THE KEY
AS TO WHERE THE GREATEST LOW LEVEL CONVERGENCE AND PRECIPITATION
DEVELOPMENT IS EXPECTED OVER THE NEXT 6 TO 12 HRS.

MOST OF THE DEEP MOISTURE AND ENERGY SHOULD QUICKLY DEPART THE FA
BY 06Z/16...OR LATE WEDNESDAY EVENING. RESIDUAL MOISTURE AND
ASSOCIATED WRAP AROUND /TROWAL/ WILL LEAD TO SOME LINGERING
SHRA/DZ IN EC/SC MN AS WELL AS WC WISCONSIN AFT 06Z/16.

THE NEXT WEATHER SYSTEM WILL LIKELY BE MOISTURE STARVED DUE TO THE
CURRENT SYSTEM TAKING MOST OF THE HIGHER PRECIPIABLE WATER CONTENT
TO THE S/SE OF OUR FA. HOWEVER...THE WAA REGIME AND SFC CONVERGENCE
ALONG THE FRONTAL BOUNDARY LATE THURSDAY/FRIDAY WILL LEAD TO CHC
POPS. LATER SHIFTS CAN ADJUST BASED ON ENERGY AND ASSOCIATED
MOISTURE ADV/CONVERGENCE.

AS WITH PREVIOUSLY FORECAST DISCUSSIONS...AM STARTING TO GET MORE
CONCERNED WITH A MORE ACTIVE WEATHER PATTERN DEVELOPING DURING THE
LATTER PART OF THE WEEKEND...AND CONTINUING THRU EARLY NEXT WEEK.
THE UPPER RIDGE THAT HAS BEEN ADVERTISED TO STRENGTHEN ACROSS THE
NORTHERN PLAINS/UPPER MIDWEST THIS WEEKEND/EARLY NEXT WEEK HAS
BEEN TRENDING SLIGHTLY SOUTHWARD WITH A MORE ELONGATED/WEAKER
UPPER RIDGE CENTERED MORE ACROSS THE SOUTHERN PLAINS. THIS WOULD
KEEP THE BAROCLINIC BOUNDARY NEAR THE UPPER MIDWEST AND ALLOW MORE
MORE SHRA/TSRA. THIS PATTERN IS ALSO MAKING ANY TYPE OF CANADIAN
AIR MASS INTRUSION TO BE DOUBTFUL. ..JLT..

&&

.AVIATION.../06Z TAF ISSUANCE/

CONFIDENCE REMAINS HIGH FOR WEATHER CONDITIONS TO DETERIORATE DURING
THE PERIOD. A STRONG WEATHER SYSTEM WILL MOVE EAST OVER THE MIDWEST
WEDNESDAY AND WEDNESDAY NIGHT. MODELS ARE IN GENERAL AGREEMENT WITH
ONLY A TIMING ISSUE NOTED ON THE SHORT AND MEDIUM RANGE MODELS. THE
LATEST UPPER AIR ANALYSIS SHOWED SHRAS AND ISOLD TSRA DEVELOPING
NORTH OF THE MID LEVEL FRONTAL BOUNDARY AS LOW LEVEL JET STRENGTHEN
OVERNIGHT INTO DAYBREAK WEDNESDAY. A SURGE OF MOISTURE AND WARM
AIR...WILL CONTINUE TO OVERRIDE THE FRONTAL BOUNDARY INITIALLY WITH
BEST FORCING ASSOCIATE WITH THE UPPER LEVEL TROUGH.

SFC TROUGH AND UPPER LEVEL TROUGH SHOULD CONTINUE TO ADVANCE EAST
OVER THE NEXT 24 TO 30 HOURS AS SYSTEM MOVES OVER WESTERN MN WED
MRNG...AND OVER CENTRAL AND EASTERN MN DURING THE AFTERNOON. RAIN
AND ISOLD TSRA SHOULD ENGULF MUCH OF THE AREA. THE EXTENT OF THE
THUNDER CHANCES DURING THE DAY UNCERTAIN...THE BEST CHANCE OF
THUNDER WILL OCCUR DURING THE OVERNIGHT HOURS AND WEDNESDAY
MORNING.

CEILING HEIGHTS OVER SOUTHERN MN...WILL VARY BETWEEN 5000-9000 FEET
AGL...GRADUALLY LOWER TO MARGINAL/IFR CONDS IN RAIN WITH
VISIBILITIES LOWERING BTWN 3-5 MILES AND CEILINGS LOWERING BELOW
1000 FEET AGL. DON'T EXPECT MUCH IN THE WAY OF IMPROVEMENT THROUGH
MUCH OF THE EVENING/NIGHTTIME HOURS.  THE RAIN IS EXPECTED TO LET UP
TOMORROW NIGHT...HOWEVER WEATHER CONDS WILL REMAIN IFR OR LOW
MARGINAL VFR CONDITIONS.

KMSP...CURRENT FORECAST SEEM REASONABLE WITH THE TIMING OF THE
PRECIPITATION STARTING BETWEEN 500 AM AND 700 AM. THUS...THE
FORECAST CONFIDENCE REMAINS HIGH WITH WEATHER CONDS LOWERING DURING
THE OVERNIGHT AND WEDNESDAY MORNING. THERE COULD BE A FEW RUMBLES OF
THUNDER IN THE MORNING SHORTLY AFTER 700 AM...OTHERWISE RAIN SHOULD
BE THE PREDOMINANT WEATHER FEATURE WEDNESDAY AND WEDNESDAY NIGHT.
CONDS WILL BE SLOW TO IMPROVE...WITH A SLIGHT IMPROVEMENT BEFORE
DAYBREAK THURSDAY.

&&

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

JLT/JVM

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
247 PM CDT TUE SEP 14 2010

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
152000-
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-
247 PM CDT TUE SEP 14 2010

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

.DAY ONE...TONIGHT

ISOLATED THUNDERSTORMS WILL BE POSSIBLE TONIGHT ACROSS CENTRAL AND
SOUTHERN MINNESOTA. THE STORMS ARE NOT EXPECTED TO BE SEVERE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NON-SEVERE...ISOLATED THUNDERSTORMS WILL BE POSSIBLE WEDNESDAY
AND WEDNESDAY NIGHT ACROSS THE OUTLOOK AREA. THUNDERSTORMS ARE
POSSIBLE ACROSS SOUTHERN MINNESOTA AND WEST CENTRAL WISCONSIN ON
SUNDAY AND MONDAY.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

RAH