Hail and Damaging Winds in Minnesota, August 3, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
530 PM CDT FRI AUG 3 2012

.UPDATED FOR 00Z AVIATION DISCUSSION...

.DISCUSSION...
MAIN FORECAST CONCERN TODAY IS OBVIOUSLY THE POTENTIAL FOR
CONVECTION AND SEVERE WEATHER TONIGHT. OTHERWISE THINGS LOOK
FAIRLY QUIET THROUGH MOST OF THE FORECAST PERIOD AS THE UPPER
RIDGE RETROGRADES TO THE WESTERN PART OF THE CONTINENT AND WE FIND
OURSELVES IN PREDOMINANTLY DRY NORTHWEST FLOW. LATEST VISIBLE
SATELLITE AND RADAR IMAGERY SHOW CONVECTION OVER THE DAKOTAS NEAR
THE SURFACE FRONTAL BOUNDARY. THE SHORTWAVE WHICH WILL DRIVE
THINGS EAST TONIGHT IS IMPRESSIVE ON WATER VAPOR IMAGERY....
CURRENTLY MOVING THROUGH MONTANA. THE MODELS ARE IN GENERAL
AGREEMENT ON THE TIMING OF THE FRONT TONIGHT... WITH DIFFERENCES
IN SOME OF THE CONVECTIVE DETAILS. THERE ARE ALSO A VARIETY OF
SOLUTIONS WITH THE CAM RUNS... ALTHOUGH MOST SUGGEST THE
DEVELOPMENT OF A SOLID LINE OF CONVECTION NEAR THE MINNESOTA-
DAKOTAS BORDER BY 00Z... WHICH WOULD THEN TRACK EAST ACROSS THE
REMAINDER OF THE CWFA THROUGH THE EVENING AND INTO THE OVERNIGHT
HOURS. BEST GUESS NOW WOULD BE FOR THE MAIN CONVECTIVE LINE TO
REACH THE I-35 CORRIDOR AROUND THE 4-5Z TIME FRAME... ALTHOUGH
MUCH WILL DEPEND ON HOW THINGS EVOLVE OVER THE NEXT SEVERAL HOURS
OVER SOUTH DAKOTA. PLENTY OF INSTABILITY IS PRESENT OVER THE
AREA... AND WILL REMAIN IN PLACE THROUGH THE EVENING. DEEP LAYER
AND LOW LEVEL SHEAR WILL ALSO INCREASE... AND LOOK TO BE MORE THAN
SUFFICIENT FOR GOOD STORM ORGANIZATION AND UPSCALE GROWTH INTO A
LINEAR MCS... SO THE SUGGESTIONS FROM THE CAMS AS WELL AS THE SSEO
SEEM PRETTY REASONABLE. MAIN THREAT LOOKS TO BE DAMAGING WIND
GUSTS... WITH SOME HAIL ALSO POSSIBLE. WOULDN/T RULE OUT THE
POSSIBILITY OF A BRIEF TORNADO OVER THE FAR WESTERN PART OF THE
AREA IF THERE ARE STILL ANY DISCRETE CELLS OR SUPERCELLS EMBEDDED
IN A QLCS STRUCTURE AT THAT POINT. THE COLD FRONT LOOKS TO CLEAR
THE AREA SOMETIME SATURDAY MORNING... AND THAT SHOULD TAKE MOST OF
THE PCPN WITH IT. SOME ACTIVITY COULD REMAIN OVER THE NORTHERN
PART OF THE AREA THROUGH THE DAY AS THE UPPER TROUGH MIGRATES
THROUGH... WITH THE HEART OF THE MID-LEVEL COLD POOL STAYING TO
OUR NORTH.

HIGH PRESSURE BUILDS IN SATURDAY NIGHT AND REMAINS ANCHORED IN
PLACE THROUGH SUNDAY NIGHT. ANOTHER FRONT WILL DROP SOUTHEAST
THROUGH THE AREA ON MONDAY... BUT WILL BE MOISTURE STARVED AND
DOES NOT LOOK TO HAVE VERY STRONG QG FORCING ASSOCIATED WITH ITS
UPPER WAVE... SO EXPECT IT TO PUSH THROUGH MOST OF THE AREA DRY.
HOWEVER... SOME SHRA/TSRA COULD EVENTUALLY DEVELOP AS IT GETS INTO
THE SOUTHERN PART OF THE AREA BY MONDAY NIGHT... SO KEPT SOME LOW
POPS TO ACCOUNT FOR THAT POSSIBILITY. AFTER THAT WE LOOK TO REMAIN
ON THE NORTHEAST PERIPHERY OF THE EXPANSIVE UPPER RIDGE FOR THE
BALANCE OF THE WEEK. SOME INSTABILITY SHOULD RETURN TO THE AREA BY
WEDNESDAY... AND FROM THEN THROUGH FRIDAY WE WILL LIKELY SEE A FEW
CHANCES FOR PCPN AS SEVERAL WEAK SHORTWAVES MIGRATE AROUND THE UPPER
RIDGE AND DROP THROUGH OUR AREA IN THE PREVAILING NORTHWEST MID-
UPPER LEVEL FLOW. IT/S POSSIBLE THAT MOST OF THAT ACTIVITY WILL
STAY NORTH/EAST OF OUR AREA DEPENDING ON WHERE THE BAROCLINIC ZONE
WINDS UP... BUT AT THIS POINT THERE IS SUFFICIENT UNCERTAINTY AND
DIVERSITY IN THE NWP SOLUTIONS TO INCLUDE SOME POPS FOR MUCH OF
THE PERIOD FROM WEDNESDAY NIGHT THROUGH FRIDAY.

&&

.AVIATION.../00Z TAF ISSUANCE/

HELD ONTO TO THE SPIRIT OF PREVIOUS FORECAST WITH JUST A BIT OF
TIMING CHANGES...MAYBE AN HOUR OR SO AT SOME LOCALES. ADDED SOME
WIND GUSTS AT KAXN/KRWF/KSTC WITH A 3 HOUR TEMPO ASSOCIATED. SHOULD
SEE LINEAR FORM OF CONVECTION IN THE EASTERN DAKOTAS NEXT HOUR OR SO
AND THEN MOVE INTO THE AREA AND MOVE EAST INTO WESTERN WI BY 06Z
SAT.  ACTIVITY EXPECTED TO WEAKEN SOME AS IT CROSSES INTO
WISCONSIN.  THEN PERIOD OF MVFR CIGS POSSIBLE EARLY IN THE MORNING
WITH FROPA...LIFTING AND CLEARING SOME DURING THE LATE MORNING.
COULD SEE REDEVELOPMENT INTO KEAU AREA IN THE AFTERNOON AND LEFT VCTS
FOR NOW...BUT SHOULD MOVE OUT AFTER 21Z SAT. SOUTHEAST SURFACE WINDS
BECOMING WEST TO NORTHWEST WITH FROPA AND PERHAPS A BIT GUSTY INTO
THE LATE MORNING/AFTERNOON.

KMSP...STILL LOOKS LIKE A 04Z-07Z TIMED EVENT FOR SIG CONVECTION IN
THE AREA.  SHOULD MOVE OUT THEREAFTER AND HELD ONTO VCSH AND THE
MVFR CIGS INTO THE EARLY MORNING.  SOUTHEAST WINDS WILL BECOME WEST
TO NORTHWEST WITH FROPA INTO SATURDAY MORNING. COULD BE A BIT GUSTY
AS SKY CLEARS SOME AND MIXING DEVELOPS. SHOULD CLEAR INTO THE LATE
AFTERNOON WITH LIGHTER NORTHWEST WINDS INTO SATURDAY EVENING.

/OUTLOOK/
.SUNDAY...VFR WITH POSSIBLE MORNING MVFR CEILINGS. WINDS NW AT
10G15KT.
.MONDAY...VFR. WINDS SW AT 10KT.
.TUESDAY...VFR/MVFR. WINDS SSW AT 5KT.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1247 PM CDT FRI AUG 3 2012

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
041800-
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-
1247 PM CDT FRI AUG 3 2012

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO ENTER WEST CENTRAL
MINNESOTA FROM THE EASTERN DAKOTAS AFTER 6 PM AND EXPAND EASTWARD
ACROSS THE OUTLOOK AREA DURING THE EVENING...REACHING WEST CENTRAL
WISCONSIN AROUND MIDNIGHT. DAMAGING WINDS...LARGE HAIL...AND
BURSTS OF HEAVY RAINFALL WILL BE POSSIBLE WITH THESE STORMS. THE
PRIMARY THREAT FOR SEVERE WEATHER WILL EXIST WEST OF LINE FROM
RUSH CITY TO FAIRMONT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORM CHANCES WILL LINGER INTO SATURDAY FROM SOUTH CENTRAL
MINNESOTA INTO WEST CENTRAL WISCONSIN. THOUGH THE THREAT OF
SEVERE WEATHER LOOKS TO BE EAST OF THE OUTLOOK AREA
SATURDAY...ISOLATED STORMS COULD FLARE UP TO SEVERE LEVELS MID DAY
SATURDAY EAST OF THE INTERSTATE 35 CORRIDOR.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL LIKELY BE NEEDED ACROSS WEST
CENTRAL MINNESOTA DURING THE LATE AFTERNOON AND EARLY
EVENING...AND ACROSS THE REMAINDER OF CENTRAL MINNESOTA TONIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
714 PM CDT FRI AUG 3 2012

MNZ054>056-064-040100-
CHIPPEWA-LAC QUI PARLE-SWIFT-YELLOW MEDICINE-
714 PM CDT FRI AUG 3 2012

...THUNDERSTORMS MOVING INTO CHIPPEWA...LAC QUI PARLE...SWIFT AND
YELLOW MEDICINE COUNTIES THROUGH 800 PM CDT...

AT 709 PM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM 18 MILES WEST OF REVILLO. THIS STORM WAS MOVING EAST AT
35 MPH.

WINDS UP TO 50 MPH AND HEAVY DOWNPOURS ARE EXPECTED WITH THIS STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  NASSAU.
  MARIETTA.
  MADISON.
  CANBY.
  MONTEVIDEO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEEK SHELTER AND STAY AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

&&

LAT...LON 4526 9646 4527 9642 4526 9629 4523 9627
      4520 9612 4522 9611 4524 9613 4534 9612
      4538 9549 4456 9550 4456 9561 4462 9562
      4463 9645 4470 9647
TIME...MOT...LOC 0013Z 264DEG 29KT 4493 9686

SPD