Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
110 PM CDT MON MAR 19 2012

.UPDATED FOR 18Z AVIATION DISCUSSION...

&&

.DISCUSSION...
/ISSUED AT 243 AM CDT MAR 19 2012/
STRONG SOUTHERLY FLOW CONTINUES EARLY THIS MORNING...BUT
ANTICIPATED SHRA/TSRA DEVELOPMENT THIS MORNING IS LACKING BASED ON
RELATIVELY DRY LAYER ABV 7H.

A VERY AMPLIFIED TROUGH ACROSS THE WESTERN U.S. HAS CREATED
SEVERAL POTENT SHRTWV/S ACROSS THE ROCKIES AND INTO THE SOUTHERN
PLAINS. ONE OF THE STRONGER WAVES HAS DEVELOPED A LINE OF
CONVECTION ACROSS WESTERN TX WHICH WILL MOVE ACROSS KS/OK/TX THIS
MORNING.

ALTHOUGH A FEW SPRINKLES MAY DEVELOP PRIOR TO NOON ACROSS SOUTHERN
MN...MOST OF THE ACTION SHOULD HOLD OFF UNTIL THE AFTN...ESPECIALLY
FOR CENTRAL MN AND WC WI WHICH MAY NOT GET ANY PRECIPITATION UNTIL
LATE MONDAY NIGHT. STILL HAVE SOME CONCERNS WITH A WEAK WAVE
ACROSS N MO WHICH MAY ALLOW FOR SOME SHRA TO DEVELOP ACROSS SE MN
BY NOON.

ANOTHER CONCERN IS CONVECTION TO THE SOUTH WHICH WILL LEAD TO
WEAKER MOISTURE ADV ACROSS THE UPPER MIDWEST. ALTHOUGH A FRONTAL
BOUNDARY WILL INCH CLOSER TO WESTERN MN BY TONIGHT...THE LACK OF
STRONG MOISTURE ADV MAY LIMIT QPF AMTS AND ASSOCIATED WIDESPREAD
CONVECTION. EARLIER FORECAST HAD CATEGORICAL POPS LATER
TODAY/TONIGHT ACROSS MOST OF THE FA...BUT THIS MAY BE TOO HIGH IF
THE CONVECTION TO THE SOUTH TAKES OVER. I HAVE SEEN SEVERAL
SCENARIOS OF THIS TYPE OF MODEL BIAS OF TAKING PRECIPITATION TOO
FAR NORTH WITH A LARGE AREA OF CONVECTION TO THE SOUTH.
THEREFORE...WILL LEAN TOWARD A LIKELY POP WITH LOWER QPF. IN
ADDITION...MODELS ARE DEPICTING A SPLIT IN THE PRECIPITATION FIELD
AS A STRONG UPPER LOW BEGINS TO DEVELOP ACROSS THE SOUTHERN
ROCKIES/SOUTHERN PLAINS AND GETS CUT OFF BY MID WEEK. SO...ONE
WAVE OF PRECIPITATION LATE TODAY/TONIGHT...WILL LIKELY BE THE MAIN
SHOW UNTIL ANOTHER ROUND OF CONVECTION DEVELOPS ACROSS THE
SOUTHERN PLAINS TUE...AND MOVES N/NE ACROSS THE UPPER MIDWEST TUE
NIGHT. THIS SCENARIO IS HIGHLY BASED ON AN UPPER RIDGE BUILDING
ACROSS THE SE U.S. AND CUTTING OFF THE UPPER LOW IN WESTERN TX.
ONCE THE UPPER LOW BEGINS TO FILL AND MEANDER N/NE...PRECIPITATION
CHC ACROSS THE UPPER MIDWEST WILL INCREASE...ESPECIALLY WHERE THE
DEFORMATION ZONE DEVELOPS ON THE NW SIDE OF THE UPPER RIDGE.

NOT ANTICIPATING ANY OTHER CHGS BASED ON HOW MODELS TRY TO MOVE
THE UPPER LOW ACROSS THE PLAINS/MIDWEST AND INTO THE EASTERN U.S.
BY THE END OF THE FORECAST PERIOD. TEMPS WILL LIKELY REMAIN ABV
NORMAL DUE TO LACK OF ANY CANADIAN AIR MASS OR MODIFIED ARCTIC AIR
MASS THROUGH THE END OF THE MONTH. ..JLT..

&&

.AVIATION.../18Z TAF ISSUANCE/
THE FORECAST CHALLENGE OVER THE NEXT 24 HOURS ARE PRECIPITATION
CHANCES. UPPER LEVEL TROUGH WILL CONTINUE TO LIFT NORTHEAST INTO THE
CENTRAL PLAINS. SHRA/ISOLD TSRA WILL CONTINUE TO SPREAD NORTHWARD
INTO THE UPPER MIDWEST THIS AFTERNOON AND TONIGHT. AS DEEPER
MOISTURE ADVECTS INTO THE UPPER MIDWEST...EXPECT MORE WIDESPREAD
MVFR AND OCCASIONAL IFR CEILING/VISIBILITIES. CONDITIONS WILL BEGIN
TO IMPROVE FROM WEST TO EAST TUESDAY MORNING.

KMSP...THE BULK OF THE SHOWERS AND ISOLATED THUNDERSTORMS SHOULD
HOLD OFF UNTIL AFTER 600 PM THIS EVENING. IN THE MEANTIME...EXPECT
CEILINGS TO LOWER TO MARGINAL VFR CONDITIONS BEFORE THEN. RAIN AND
ISOLATED THUNDERSTORMS LINGERING DURING THE OVERNIGHT HOURS...WITH
CONDITIONS SLOWLY IMPROVING DURING THE AFTERNOON TUESDAY.

OUTLOOK...
.TUES-WED...IFR CIGS POSSIBLE WITH SHRA ALONG SLOW MOVING COLD
FRONT. TSRA POSSIBLE BUT NOT LIKELY.
.THUR-FRI...LOW CONFIDENCE...MVFR WITH -SHRA.

&&

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

JLT/JM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1114 AM CDT MON MAR 19 2012

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
201615-
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-
1114 AM CDT MON MAR 19 2012

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL BEGIN TO DEVELOP LATER THIS AFTERNOON
...ESPECIALLY ACROSS WESTERN MINNESOTA. THESE STORMS WILL MOVE
ACROSS CENTRAL AND EASTERN MINNESOTA DURING THE EVENING...AND
THROUGH WESTERN WISCONSIN OVERNIGHT. SOME OF THE STRONGER STORMS
MAY PRODUCE SMALL HAIL AND GUSTY WINDS. THE THREAT OF SEVERE
THUNDERSTORMS IS LOW...BUT BRIEF HEAVY RAINFALL IS LIKELY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THUNDERSTORMS WILL BE POSSIBLE ACROSS MAINLY EASTERN MINNESOTA
AND WESTERN WISCONSIN TUESDAY. SEVERE WEATHER IS NOT EXPECTED
AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

AZ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
238 PM CDT MON MAR 19 2012

MNZ054>056-064-192015-
CHIPPEWA-LAC QUI PARLE-SWIFT-YELLOW MEDICINE-
238 PM CDT MON MAR 19 2012

AT 237 PM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM 7 MILES SOUTH OF MADISON...OR 9 MILES NORTHWEST OF
PROVIDENCE. THIS STORM WAS MOVING NORTH AT 40 MPH.

HAIL UP TO NICKEL SIZE AND WINDS UP TO 55 MPH ARE EXPECTED WITH THIS
STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  MADISON.
  CERRO GORDO.
  LOUISBURG.
  HOLLOWAY.

LAT...LON 4526 9633 4526 9629 4523 9627 4520 9612
      4523 9611 4524 9613 4530 9613 4535 9612
      4536 9611 4521 9579 4475 9606 4478 9633
TIME...MOT...LOC 1939Z 181DEG 69KT 4495 9618

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
313 PM CDT MON MAR 19 2012

MNZ047-048-055-192100-
POPE-STEVENS-SWIFT-
313 PM CDT MON MAR 19 2012

AT 310 PM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM 4 MILES NORTHEAST OF CORRELL. THIS STORM WAS MOVING
NORTH AT 45 MPH.

HAIL UP TO NICKEL SIZE AND WINDS UP TO 55 MPH ARE EXPECTED WITH THIS
STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  HOLLOWAY.
  HANCOCK.
  ALBERTA.
  DONNELLY.

LAT...LON 4577 9599 4574 9544 4518 9569 4525 9613
      4540 9613 4541 9624 4576 9626
TIME...MOT...LOC 2013Z 182DEG 40KT 4530 9610