Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
705 AM CDT WED MAY 11 2011...UPDATED FOR 12 TAF

.DISCUSSION...
A RATHER COMPLICATED FORECAST NOT ONLY FOR TODAY BUT FOR THE NEXT
SEVERAL DAYS AS DOUBLE BARREL UPPER LOWS AFFECT AREA.  THRU THURSDAY
MAIN INFLUENCE WILL BE FROM THE DEEP UPPER LOW CURRENTLY OVER THE SW
U.S. AS IT EJECTS PIECES OF ENERGY NORTHWARD.  THEN WE ARE UNDER THE
EFFECTS OF UPPER LOW CURRENTLY LIFTING NE ACROSS MB INTO OT WHICH
THEN BOOMERANGS BACK INTO AREA FRIDAY AND INTO THE WEEKEND.

SATELLITE IMAGERY SHOWS TWO FAIRLY WELL DEFINED SHORTWAVES WHICH
WILL BRING IN SHOWERS/TSTMS FOR TODAY. LEAD FEATURE IS NOW
APPROACHING SW IA AND IS ALREADY SPREADING PRECIP BACK INTO SW MN.
THIS AREA OF PRECIP WILL SPRED ACRS ABOUT THE SE 1/2 OF CWA THIS
MORNING. HRRR LOOKS LIKE IT HAS A GOOD HANDLE ON THIS FIRST WAVE.
SECOND FEATURE NOW LIFTING NE ACRS E OK AND WILL PROVIDE SUPPORT FOR
ANOTHER ROUND OF TSTMS THIS AFTN. DIFFICULT TO SAY WHERE SFC FRONT
WILL LIE DURING THE AFTN AND THERE ARE DIFFERENCES BTWN NAM/GFS WITH
NAM POSITION A BIT FARTHER EAST KEEPING BEST SBCAPE CONFINED TO SE
CORNER OF MN INTO WI. CLOUDS SHOULD DAMPEN HEATING TODAY WHICH WILL
LIMIT INSTABILITY SOMEWHAT...BUT STILL THE POSSIBILITY OF SOME
HAILERS FROM SC MN INTO WC WI.

DEWPOINT FORECAST ALSO A CHALLENGE TODAY. SURGE OF DRY AIR PUSHED
WELL INTO AREA YESTERDAY AFTERNOON AND DURING NIGHT BEHIND SURFACE
TROF.  CURRENTLY MID 40 DEWPOINTS ARE COMMON ACROSS W 1/2 CWA.
SHOWERS SPREADING BACK INTO AREA WILL ELEVATE THEM DURING THE
DAY...BUT THEY MAY STAY IN THE 40S UP TOWARD AXN/MOX.

MAY BE A BIT OF A BREAK IN PCPN DEVELOPING IN THE EVENING AS SECOND
SHORTWAVE LIFTS THRU...BUT PWATS REMAIN QUITE HIGH ESPECIALLY ACRS S
CWA AND MID LVLS STILL FAIRLY UNSTBL.  CONFINED QPF VALUES MUCH OVER
.20 TO SC MN.

GFS QUITE A BIT MORE AGGESSSIVE THAN NAM ON QPF FOR THURSDAY WITH
STRONGER UPPER DIVERGENCE ACROSS S MN ASSOCIATED WITH UPPER LOW OVER
KS. CUT BACK A BIT ON OUR GOING POPS THURSDAY.

MUCH COLDER AIRMASS INTRUDES FROM THE NORTH BEGINNING THURSDAY INTO
THE WEEKEND AS HIGH PRESSURE BUILDS SOUTH OUT OF CANADA KEEPING
NORTHERLY WINDS ACROSS OUR AREA. COLD UPPER LOW DROPPING SOUTH THRU
AREA WILL BRING SCATTERED SHOWERS INTO SUNDAY.

&&

.AVIATION.../12Z TAF ISSUANCE/

INVERTED TROUGH THRUSTING NE ACROSS SOUTHERN HALF OF MINNESOTA FROM
STRONG SURFACE CYCLONE OVER WESTERN KS WILL BE MAIN GENERATOR OF
MAINLY LIGHT TO MODERATE SHOWERS AND ISOLATED THUNDER INTO THIS
EVENING...ESPECIALLY FROM SOUTH CENTRAL MN TO WEST CENTRAL WI.
VFR CIGS AND VSBYS WILL PREVAIL TODAY...SAVE STC...WHICH WILL CONTEND
WITH MVR VSBYS PRIOR TO 13Z. THETA E ADVECTION AND MOISTURE TRANSPORT
STILL POINTING TO TWO SLUGS OF MOISTURE AFFECTING AIRPORT VENUES.
ONE OF COURSE THIS MORNING...AND THE OTHER AREA DEVELOPING LATE
THIS AFTN INTO THE MID EVENING HOURS...WITH LATER DEVELOPMENT
ANTICIPATED ACROSS WI AND EAST CENTRAL MN SITES. DECENT SLUG OF
LI'S WILL OVERSPREAD MUCH OF THE SOUTHERN QUARTER OF MN DURING
THE EVENING HOURS. LACK OF HEATING AND LOWER DEWPOINTS LIMITS
ANOTHER SIGNIFICANT ROUND OF SEVERE WEATHER AS WAS SEEN YESTERDAY
AFTERNOON AND EVE. POTENTIAL IS THERE FOR MVFR CIGS LATE TONIGHT
ACROSS MOST TAF SITES...WITH NW FLOW STRONG ENOUGH TO KEEP MOST
AREAS FREE FROM DENSE FOG. LOWEST CIGS SHOULD MATERIALIZE OVER
AXN...EAU AND RNH.

KMSP...SCT LIGHT SHOWER ACTIVITY WILL OVERSPREAD MSP SITE AFT
14Z. POSITIVE LI'S POINTING TO LIMITED CHANCES FOR T-STORM ACTIVITY
THIS MORNING...BUT INCREASING BY LATE AFTN AS INVERTED TROUGH
PIVOTS SE ACROSS WEST CENTRAL WI AND EAST CENTRAL/SE MN. VFR CIG
AND VSBY WILL HOLD OVER KMSP FOR MAJORITY OF PERIOD...SAVE FOR
T-STORM INTRUSION LATER THIS AFTN. ALTHOUGH HAVE LEFT OUT ANY
LOWERING OF CLOUD DECK LATE TONIGHT THERE IS A CHANCE FOR LIMITED
MVFR CIGS THIS LOCATION...WITH VFR CIGS EXPECTED TO CONTINUE INTO
THURSDAY.

&&

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

BAP/AZ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
441 AM CDT WED MAY 11 2011

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
120945-
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-
441 AM CDT WED MAY 11 2011

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

.DAY ONE...TODAY AND TONIGHT
SHOWERS AND SOME THUNDERSTORMS WILL SPREAD OUT OF IOWA THEN MAINLY
ACROSS SOUTHERN AND EAST CENTRAL MINNESOTA EARLY THIS MORNING AND
INTO WEST CENTRAL WISCONSIN BEFORE NOON. THESE STORMS ARE NOT
EXPECTED TO BE SEVERE. ANOTHER ROUND OF THUNDERSTORMS IS POSSIBLE
THIS AFTERNOON AND EVENING...MAINLY ACROSS SOUTH CENTRAL MINNESOTA
INTO WEST CENTRAL WISCONSIN. HAIL WILL BE THE PRIMARY SEVERE
WEATHER THREAT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF THE OUTLOOK AREA
THURSDAY AND THURSDAY NIGHT AS A LOW PRESSURE SYSTEM LINGERS OVER
THE UPPER MISSISSIPPI VALLEY.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION MAY BE NEEDED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
951 AM CDT WED MAY 11 2011

WIZ025-027-028-111545-
CHIPPEWA-DUNN-EAU CLAIRE-
951 AM CDT WED MAY 11 2011

...THUNDERSTORMS MOVING OVER CHIPPEWA...DUNN AND EAU CLAIRE COUNTIES
THROUGH 1045 AM CDT...

AT 946 AM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM 4 MILES NORTHWEST OF CARYVILLE. THIS STORM WAS MOVING
NORTHEAST AT 20 MPH.

ONE HALF INCH DIAMETER HAIL AND WINDS UP TO 30 MPH ARE EXPECTED WITH
THIS STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  CARYVILLE.
  MENOMONIE.
  ELK MOUND.
  TAINTER LAKE.
  LAKE HALLIE.
  COLFAX.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 4521 9207 4520 9099 4465 9133 4475 9209
TIME...MOT...LOC 1451Z 205DEG 19KT 4481 9172

TRH