Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1132 PM CDT SAT MAY 19 2012

.DISCUSSION...

LOOKS LIKE AN ACTIVE NEAR TERM WITH SHOWERS AND THUNDERSTORMS
DEVELOPING SATURDAY AFTERNOON AND LASTING THROUGH THE OVERNIGHT
HOURS BEFORE EXITING THE REGION SUNDAY AFTERNOON. THIS WILL BE
FOLLOWED BY HIGH PRESSURE BUILDING IN SUNDAY NIGHT THROUGH
TUESDAY...WITH A RETURN TO ACTIVE WEATHER FOR THE LATTER HALF OF
THE PERIOD.

TODAY THROUGH TUESDAY...AFTERNOON WATER VAPOR IMAGERY INDICATED A
WIDESPREAD REGION OF ASCENT ACROSS THE UPPER MIDWEST DOWNSTREAM
OF A LONGWAVE TROUGH CENTERED ACROSS THE KS/NE BORDER. A SHORTWAVE
WAS ROUNDING THE BASE OF THIS TROUGH AND FORCING A FEW
THUNDERSTORMS ACROSS THE MISSOURI RIVER VALLEY. CLOSER TO HOME A
COLD FRONT WAS MOVING THROUGH THE REGION...AND AS OF THIS
AFTERNOON WAS LOCATED ALONG A LINE FROM REDWOOD FALLS THROUGH
LITTLE FALLS. A FEW SHOWERS AND THUNDERSTORMS WERE BEGINNING TO
DEVELOP ALONG AND BEHIND THIS SURFACE FRONTAL BOUNDARY. THESE
SHOWERS SHOULD INCREASE IN COVERAGE LATER THIS EVENING AND
OVERNIGHT AS THE AFOREMENTIONED SHORTWAVE MOVES NORTHEAST ACROSS
THE REGION. FORECAST SOUNDINGS INDICATE UNIDIRECTIONAL SHEAR THIS
EVENING...WITH MLCAPES OF AROUND 1000 TO 1500 J/KG AHEAD OF THE
FRONT. THESE CAPE VALUES MAY NOT BE REALIZED IF THE CONVECTION IS
MAINLY FOCUSED IN THE POST FRONTAL AIRMASS...BUT COULD SEE ENOUGH
ELEVATED INSTABILITY FOR UPDRAFTS THAT SUPPORT LARGE HAIL...WITH
DAMAGING WIND ALSO POSSIBLE BENEATH COLLAPSING PRECIP CORES. THE
CONVECTION WILL SUBSIDE LATER TONIGHT...AND A SECOND AREA OF
PRECIP IS EXPECTED TO FORM ALONG THE DEFORMATION AXIS ALONG THE
ARROWHEAD OF MINNESOTA INTO THE CENTRAL PART OF THE STATE. USED 3
HR GRIDS AND TRIED TO ADJUST THE PRECIP CHANCES TO REFLECT
THIS. ONCE THIS SYSTEM MOVES NORTHEAST...WE SHOULD QUICKLY DRY OUT
TOMORROW AFTERNOON...WITH CLEAR SKIES AND COOL TEMPS FOR SUNDAY
NIGHT. HIGH PRESSURE WILL BUILD IN FOR MONDAY. ON TUESDAY...A
POWERFUL JET WILL MOVE ONSHORE THE PACIFIC NORTHWEST AND CROSS THE
NORTHERN ROCKIES. AT THE SURFACE...A LOW PRESSURE SYSTEM WILL
RAPIDLY INTENSIFY ACROSS THE WESTERN DAKOTAS AND DRAW UP WARM AIR
ACROSS THE REGION. THE LAST FEW RUNS OF THE NAM TRY TO INDICATE
SOME SHOWERS AND THUNDERSTORMS ON TUESDAY...BUT WENT WITH A DRY
FORECAST FOR NOW.

WEDNESDAY THROUGH SATURDAY...THIS JET WILL CONTINUE TO DIG A TROUGH
OVER THE HIGH PLAINS...WITH THE AFOREMENTIONED SURFACE LOW MOVING
NORTHEAST FROM THE DAKOTAS INTO SOUTHERN CANADA WHICH WILL SWING A
COLD FRONT THROUGH THE REGION WEDNESDAY NIGHT. SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG THIS BOUNDARY...WHICH WILL STALL
OUT ACROSS THE UPPER MIDWEST. THIS WILL BE THE FOCUS FOR SHOWERS
AND THUNDERSTORMS FOR THE REST OF NEXT WEEK. THE GFS 19.12 IS
FURTHER SOUTH WITH THIS FRONT THAN THE ECMWF 19.12. CONVECTION
WILL LIKELY INFLUENCE THE EXACT PLACEMENT...SO WENT WITH A BLEND
OF THE TWO ALONG WITH THE PREVIOUS FORECAST GIVEN THE UNCERTAINTY.
FOR THE MEMORIAL DAY WEEKEND...BOTH LONG RANGE MODELS BUILD A
THERMAL RIDGE ACROSS THE CENTRAL CONUS...WHICH WOULD EQUATE TO
WARM WEATHER.

&&

.AVIATION.../06Z TAF ISSUANCE/
THE MAIN AVIATION CONCERN REMAINS THE THREAT OF THUNDERSTORMS
THROUGH SUNDAY MORNING. MESOSCALE CONVECTIVE COMPLEX WAS CENTERED
OVER SOUTHERN MN. THE BACK OF THE COMPLEX EXTENDS OVER THE EASTERN
SOUTH DAKOTA AND SOUTHWEST IOWA AT THIS TIME. SYSTEM WILL CONTINUE
TO ADVANCE NORTHEAST OVERNIGHT WITH SHOWERS AND THUNDERSTORMS
CONTINUING OVER MUCH OF THE FORECAST AREA. CEILINGS/VISIBILITIES
LOWER TO IFR CONDITIONS IN HEAVY RAIN. SOME SMALL HAIL IS ALSO
POSSIBLE. CONDITIONS WILL BEGIN TO IMPROVE FROM WEST TO EAST TOWARD
DAYBREAK SUNDAY IN WESTERN MN AND DURING THE AFTERNOON SUNDAY OVER
IN WESTERN WISCONSIN. EXPECT CONDS TO IMPROVE TO VFR BEFORE NOON
SUNDAY IN THE KAXN AREA...AND NOT IN THE KEAU AREA UNTIL AFTER 300
PM IN KEAU. NORTH-NORTHWEST WINDS WILL CONTINUE TO USHER IN DRIER
AIR...ESPECIALLY DURING THE DAY ON SUNDAY.

KMSP...LARGE CLUSTER OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT OVER THE AREA OVERNIGHT. EXPECT OCCASIONAL IFR WEATHER
CONDITIONS IN HEAVY RAIN AND THUNDERSTORMS.  CONDITIONS WILL BEGIN
TO IMPROVE SUNDAY AFTERNOON AS DRIER AIR FILTER OVER THE AREA. SOME
PATCHY OR AREAS OF FOG DEVELOPING IN LOW LYING AREAS SUNDAY NIGHT.

OUTLOOK...
SUN NIGHT AND MONDAY MORNING...PATCHY AREAS OF FOG.
MON-TUE...VFR.

&&

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

JRB/JM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1036 PM CDT SAT MAY 19 2012

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
201200-
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-
1036 PM CDT SAT MAY 19 2012

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

.DAY ONE...TONIGHT

EXPECT NON-SEVERE THUNDERSTORMS DURING THE OVERNIGHT TONIGHT. BRIEF
HEAVY RAIN...SMALL HAIL AND WIND GUST TO AROUND 45 MPH ARE LIKELY
WITH THE STRONGER STORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORM CHANCES WILL CONTINUE INTO SUNDAY MORNING AHEAD OF
THE COLD FRONT IN WESTERN WISCONSIN. THE THREAT FOR SEVERE WEATHER
APPEARS LOW AT THIS TIME.

MORE THUNDERSTORMS WILL BE POSSIBLE WEDNESDAY THROUGH FRIDAY AS A
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT. THIS FRONT LOOKS TO
STALL OUT AND REMAIN OVER OR NEAR THE OUTLOOK AREA THURSDAY AND
FRIDAY. SEVERE WEATHER COULD BE POSSIBLE DEPENDING ON THE FRONTS
PLACEMENT THURSDAY AND FRIDAY AFTERNOONS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
838 PM CDT SAT MAY 19 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0835 PM     HAIL             2 N LONG LAKE           45.01N 93.57W
05/19/2012  M0.88 INCH       HENNEPIN           MN   TRAINED SPOTTER

&&

CARLYON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
849 PM CDT SAT MAY 19 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 PM     TSTM WND DMG     MINNEAPOLIS             44.96N 93.27W
05/19/2012                   HENNEPIN           MN   TRAINED SPOTTER

            TWO 12 INCH DIAMETER TREES DOWN NEAR INTERSECTION OF SE
            ELM STREET AND SE KASOTA AVE. APPROXIMATE TIME.

&&

CARLYON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
852 PM CDT SAT MAY 19 2012

MNZ044-045-051>053-059>063-066>070-WIZ023-024-200315-
ANOKA-CARVER-CHISAGO-DAKOTA-HENNEPIN-ISANTI-KANABEC-MCLEOD-MILLE
LACS-PIERCE-RAMSEY-SCOTT-SHERBURNE-SIBLEY-ST.
CROIX-WASHINGTON-WRIGHT-
852 PM CDT SAT MAY 19 2012

...THUNDERSTORMS DEVELOPING OVER EAST CENTRAL MINNESOTA AND WEST
CENTRAL WISCONSIN THROUGH 1015 PM CDT...

AT 843 PM CDT...RADAR INDICATED THAT NUMEROUS THUNDERSTORMS WERE
RAPIDLY DEVELOPING OVER EAST CENTRAL MINNESOTA INTO WEST CENTRAL
WISCONSIN.  THE STRONGER STORMS REMAINED NEAR
PLYMOUTH...ANOKA...HUDSON AND LUCK WISCONSIN.  THESE STORMS WERE
MOVING NORTHEAST AT 35 MPH.

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

* LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE...
  NEW HOPE.
  OSSEO.
  BROOKLYN PARK.
  SPRING LAKE PARK.
  COON RAPIDS.
  BLAINE.
  ST PAUL.
  MINNEAPOLIS.
  STILLWATER.
  FOREST LAKE.
  LINDSTROM.
  CAMBRIDGE.

THE STORMS ARE EXPECTED TO CONTINUE THROUGH AT LEAST MIDNIGHT ACROSS
MUCH OF THE REGION.  ALONG WITH THE WIND AND HAIL...TORRENTIAL RAIN
CAN ALSO BE EXPECTED...WHICH WILL CAUSE LOCAL PONDING OF WATER ALONG
HIGHWAY UNDERPASSES AND ROADSIDE DITCHES.

LAT...LON 4574 9351 4572 9290 4554 9288 4541 9268
      4532 9277 4456 9280 4455 9387 4449 9408
      4488 9402 4526 9384
TIME...MOT...LOC 0146Z 222DEG 29KT 4507 9343

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
852 PM CDT SAT MAY 19 2012

MNZ065>067-074>076-082-083-200230-
BLUE EARTH-BROWN-LE SUEUR-MCLEOD-NICOLLET-RENVILLE-SIBLEY-WATONWAN-
852 PM CDT SAT MAY 19 2012

AT 848 PM CDT...WEATHER SERVICE RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS EXTENDING FROM 6 MILES SOUTH OF SLEEPY EYE TO
NORTHEAST OF ST. GEORGE.  THESE STORMS WERE MOVING NORTHEAST AT
35 MPH.

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

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  COMFREY.
  HANSKA.
  SLEEPY EYE.
  NEW ULM.
  COURTLAND.
  ST GEORGE.

LAT...LON 4395 9463 4413 9496 4468 9443 4452 9383
TIME...MOT...LOC 0151Z 213DEG 30KT 4423 9474

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1228 AM CDT SUN MAY 20 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0630 PM     TSTM WND DMG     ST PAUL                 44.95N 93.10W
05/19/2012                   RAMSEY             MN   TRAINED SPOTTER

            NEAR ST. THOMAS UNIV. 10 COTTONWOOD TREE LIMB DOWN

&&

L. SCHALLER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
110 AM CDT SUN MAY 20 2012

MNZ043>045-049-050-200700-
BENTON-KANABEC-MILLE LACS-MORRISON-STEARNS-
110 AM CDT SUN MAY 20 2012

...THUNDERSTORMS MOVING OVER BENTON...KANABEC...MILLE
LACS...MORRISON AND STEARNS COUNTIES THROUGH 200 AM CDT...

AT 106 AM CDT...WEATHER SERVICE RADAR WAS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM 3 MILES NORTHEAST OF RICE
TO 4 MILES EAST OF GILMAN TO 3 MILES SOUTHEAST OF PEASE. THESE STORMS
WERE MOVING NORTH AT 50 MPH.

HAIL UP TO DIME SIZE AND HEAVY DOWNPOURS ARE EXPECTED WITH THESE
STORMS.

* LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE...
  GILMAN.
  MILACA.
  RUM RIVER.
  BOCK.
  PIERZ.
  LASTRUP.
  HARDING.
  ONAMIA.
  MILLE LACS LAKE.

LAT...LON 4617 9342 4616 9331 4573 9346 4573 9351
      4556 9352 4556 9356 4569 9390 4572 9433
      4616 9418 4616 9383 4625 9381 4626 9344
TIME...MOT...LOC 0608Z 194DEG 46KT 4580 9417 4578 9387
          4568 9361