Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
620 AM CDT FRI JUN 25 2010

UPDATED TO ADD THE 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...

A SEVERE WEATHER EVENT IS EXPECTED TO UNFOLD LATER TODAY ACROSS
MUCH OF THE FORECAST AREA...AS A SURFACE BOUNDARY SETS UP OVER
SOUTHERN MN. ADDITIONALLY...IT COULD BE A ONE-TWO PUNCH OF SEVERE
WEATHER OVER THE NEXT 48 HOURS...AS THE AFOREMENTIONED BOUNDARY
LINGERS ACROSS THE CWA ON SATURDAY.

EARLY MORNING WATER VAPOR IMAGERY SHOWS A COLLECTION OF MID LEVEL
IMPULSES DROPPING FROM SOUTHERN SASKATCHEWAN/MANITOBA INTO
NORTHERN MN. ASSOCIATED CONVECTION CONTINUES TO SPAWN OVER NORTH
DAKOTA AND NORTHERN MN OVERNIGHT...ON THE NOSE OF DECENT 850-700MB
MOISTURE TRANSPORT. WHILE ISOLD-SCT SHOWERS/TS ARE EXPECTED TO
GRADUALLY SPREAD INTO THE CENTRAL MN PORTION OF THE CWA THIS
MORNING...THE MORE WIDESPREAD AND POTENTIALLY SEVERE ACTIVITY IS
EXPECTED TO ARRIVE THIS AFTERNOON/EVE AS DESTABILIZATION OCCURS IN
THE VICINITY OF THE BOUNDARY OVER SOUTHERN MN. SUPERCELLULAR STORM
MODE APPEARS PROBABLE THIS AFTERNOON/EVE FROM CENTRAL INTO SOUTH
CENTRAL MN WITH PROGGED 0-6KM BULK SHEAR VALUES OF 50-60 KTS.
FORECAST ML CAPE TO 3 KM OF 100 J/KG AND 0-1KM EHI VALUES OF 2-4
MS/S2 ALSO ILLUSTRATE THE POTENTIAL FOR TORNADOGENESIS OVER
CENTRAL/SOUTH CENTRAL MN THIS AFTN/EVE. EXPECT THE STORM
MODE/THREATS TO TRANSITION TO A MCS/DAMAGING WIND SCENARIO AS THE
EVENING PROGRESSES. HEAVY RAINFALL WILL BECOME A CONCERN LATER THIS
EVENING AND TONIGHT...AS AN AREA OF DIFFLUENT THICKNESS SETS UP FROM
CENTRAL MN INTO WEST CENTRAL WI...WHERE PWAT VALUES SURGE TO NEARLY
200 PERCENT OF NORMAL /2 INCHES/. HAVE RELEGATED 90 POPS AND 1-2
INCH QPF VALUES OVER THIS AREA OF CENTRAL MN AND WEST CENTRAL WI FOR
TONIGHT.

FORECAST CONFIDENCE WAS INITIALLY WAVERING A BIT FOR
SATURDAY...DUE IN PART TO THE 25.00Z RUN OF THE NAM...WHICH PUSHED
THE BOUNDARY AND IMPETUS FOR SEVERE STORMS SOUTH OF THE FORECAST
AREA. HOWEVER...THE 25.06Z RUN OF THE NAM HAS COME BACK IN LINE
WITH THE MAJORITY OF THE DETERMINISTIC AND ENSEMBLE MEAN
SOLUTIONS...INCLUDING THE 25.00Z ECMWF...WHICH KEEP THE FRONT
SITUATED OVER CNTRL/SRN MN INTO WEST CENTRAL WI ON SATURDAY
AFTERNOON. HAVE THEREFORE INCLUDED 70-80 POPS ACROSS THE MAJORITY
OF THE CWA ON SATURDAY AFTN/NIGHT. THE FEATURE THAT THE SATURDAY
EVENT WOULD HAVE GOING FOR IT THAT TODAY/S EVENT DOESN/T...IS THE
ENTRANCE REGION OF A 100 KT JET IN PLACE OVERHEAD.

SUNDAY SHOULD WIND UP BEING A MOSTLY DRY DAY...OTHER THAN POSSIBLY
A FEW LINGERING SHOWERS IN THE MORNING ACROSS EAST CENTRAL MN AND
WEST CENTRAL WI.

A RIDGE OF HIGH PRESSURE BUILDS ACROSS THE AREA THROUGH AT LEAST
THE MIDDLE OF NEXT WEEK...WHICH WILL BRING DRY AND MILD CONDITIONS
TO CLOSE OUT THE MONTH OF JUNE.

&&

.AVIATION... /12Z TAF ISSUANCE/

COVECTIVE COMPLEX OVER NORTH CENTRAL MN...WILL CONTINUE TO WEAKEN AS
IT MOVES INTO A MORE STABLE AIRMASS THIS MORNING. ON THE SOUTHERN
END OF THE COMPLEX...EXPECT A FEW THUNDERSTORMS MAY DEVELOP AS FAR
SOUTH NEAR KAXN AND KSTC. ELSEWHERE...MID/UPPER LEVEL IMPLUSES...ARE
EXPECTED TO TRIGGER THUNDERSTORMS OVER THE UPPER MIDWEST THIS
AFTERNOON AND EVENING. FRONTAL BOUNDARY IS FORECAST TO PUSH
SOUTH-EAST OVER SOUTHERN MINNESOTA TONIGHT...THEN BECOME
QUASI-STATIONARY. AIRMASS EXPECTED TO DESTABLIZE OVER A VAST PART OF
THE CENTRAL AND SOUTH CENTRAL MN AND WESTERN WISCONSIN LATER THIS
AFTERNOON. IMPLUSE OVER SOUTH DAKOTA...SHOULD HELP FIRE OFF SOME
INTENSE STORMS LATER...WEATHER CONDS LOWERING TO MVFR TO IFR CONDS
IN THE VICINITY OF THE STORMS. MAINLY VFR CONDS THROUGH THE BULK OF
THE DAY.  WEATHER CONDITIONS LOWERING OVERNIGHT TO MVFR-IFR CATEGORY
IN LOW CLOUDS AND FOG.

KMSP...VFR CONDS CONTINUES THRU MID AFTERNOON.  WEATHER CONDS WILL
LOWER TO MVFR/IFR CATEGORY LATE AFTERNOON AND EVENING AS CONVECTION
INITIATES. SOME IMPROVEMENT OVERNIGHT..THEN CLOUDS/CEILING LOWERING
TO UNDER 2000 FEET AGL AND VISIBILITY 3-5 MILES IN FOG. SFC WINDS
SOUTH-SOUTHWEST 10-20 MPH...BECOMING NORTHERLY AFTER FRONTAL
PASSAGE.

&&

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

LS/JM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
437 AM CDT FRI JUN 25 2010

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
260945-
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-
437 AM CDT FRI JUN 25 2010

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

.DAY ONE...TODAY AND TONIGHT

SEVERE THUNDERSTORMS ARE EXPECTED ACROSS THE OUTLOOK AREA THIS
AFTERNOON AND TONIGHT...AS A WARM FRONT SETS UP OVER SOUTHERN
MINNESOTA. THE STORM MODE IS INITIALLY EXPECTED TO BE OF THE
SUPERCELL NATURE...WITH THE ATTENDANT THREATS BEING LARGE HAIL AND
DAMAGING WINDS. A FEW TORNADOES WILL ALSO BE POSSIBLE THIS
AFTERNOON AND EVENING. THE STORMS ARE EXPECTED TO CONGEAL INTO A
COMPLEX THIS EVENING AND TONIGHT...WITH THE PRIMARY THREATS
BECOMING DAMAGING WINDS AND HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE FRONTAL BOUNDARY IS EXPECTED TO LINGER IN THE AREA ON
SATURDAY...WITH THUNDERSTORM REDEVELOPMENT ANTICIPATED ON SATURDAY
AFTERNOON AND EVENING. ANOTHER ROUND OF SEVERE STORMS IS
EXPECTED...WITH THE POTENTIAL FOR DAMAGING WINDS...LARGE
HAIL...AND A FEW TORNADOES. HEAVY RAINFALL WILL ALSO BE
POSSIBLE...ESPECIALLY ON SATURDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL LIKELY BE NEEDED THIS AFTERNOON
AND EVENING...AND AGAIN ON SATURDAY AFTERNOON AND EVENING.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
607 AM CDT FRI JUN 25 2010

MNZ041>043-048-049-251215-
DOUGLAS-MORRISON-POPE-STEARNS-TODD-
607 AM CDT FRI JUN 25 2010

...THUNDERSTORMS WILL MOVE INTO DOUGLAS...MORRISON...POPE...STEARNS
AND TODD COUNTIES BETWEEN 615 AM CDT AND 715 AM CDT...

AT 600 AM CDT...WEATHER SERVICE RADAR WAS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM 10 MILES NORTHEAST OF
WADENA TO 7 MILES WEST OF CAMPBELL. THESE STORMS WERE MOVING SOUTHEAST AT
50 MPH.

HAIL UP TO DIME SIZE AND WINDS UP TO 50 MPH ARE EXPECTED WITH THESE
STORMS.

* LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE...
  HEWITT.
  MELBY.
  MOTLEY.
  PHILBROOK.
  ROSE CITY.
  KENSINGTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.

&&

LAT...LON 4631 9455 4634 9442 4629 9434 4623 9439
      4617 9436 4616 9394 4612 9383 4565 9467
      4566 9541 4577 9577 4610 9577 4611 9516
      4637 9516 4638 9473
TIME...MOT...LOC 1106Z 290DEG 46KT 4654 9494 4607 9648

LS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
645 AM CDT FRI JUN 25 2010

MNZ041-047-048-251245-
DOUGLAS-POPE-STEVENS-
645 AM CDT FRI JUN 25 2010

...THUNDERSTORMS MOVING INTO DOUGLAS...POPE AND STEVENS COUNTIES
THROUGH 745 AM CDT...

AT 643 AM CDT...WEATHER SERVICE RADAR WAS TRACKING A SEVERE
THUNDERSTORM 6 MILES SOUTHWEST OF ELBOW LAKE. THIS STORM WAS MOVING
SOUTHEAST AT 40 MPH.

HAIL UP TO DIME SIZE AND WINDS UP TO 50 MPH ARE EXPECTED WITH THIS
STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  DONNELLY.
  KENSINGTON.
  FARWELL.
  LOWRY.
  STARBUCK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.

&&

LAT...LON 4577 9577 4595 9578 4604 9577 4591 9516
      4543 9514 4542 9592 4576 9613
TIME...MOT...LOC 1144Z 305DEG 37KT 4591 9603

LS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
839 AM CDT FRI JUN 25 2010

MNZ047-048-055-251430-
POPE-STEVENS-SWIFT-
839 AM CDT FRI JUN 25 2010

AT 831 AM CDT...WEATHER SERVICE RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS OVER NORTHEAST SOUTH DAKOTA...MOVING EAST AT 45 MPH.

HAIL UP TO DIME SIZE AND WINDS UP TO 50 MPH ARE POSSIBLE WITH THESE
STORMS...WHICH COULD REACH STEVENS COUNTY AFTER 9 AM.

* LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE...
  CHOKIO.
  DONNELLY.
  ALBERTA.
  MORRIS.
  CYRUS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE THUNDERSTORMS COULD INTENSIFY...SO BE READY TO ACT IF A
WARNING IS ISSUED.

&&

LAT...LON 4570 9626 4569 9553 4533 9612 4534 9613
      4540 9614 4541 9625 4567 9627
TIME...MOT...LOC 1336Z 274DEG 38KT 4564 9656 4539 9705