Hail in Minnesota, June 18, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
329 PM CDT SAT JUN 18 2011

.DISCUSSION...

INTERESTING SCENARIO TODAY AS CONVECTION DEVELOPED NORTHEAST FROM
WESTERN IA INTO THE TWIN CITIES...NEARLY PERPENDICULAR TO THE
SURFACE TROF ACROSS THE LOCAL AREA. THE CONVECTION WAS TAPPING
HIGH LEVEL MOISTURE FROM AN OVERNIGHT COMPLEX TO OUR SOUTH. THIS
HAS LEAD TO EFFICIENT RAIN PRODUCERS WITH REPORTS OF A HALF INCH
IN 15 MINUTES RECEIVED WITHIN THE HOUR. THE HIGH LEVEL MOISTURE
PLUME IS ALIGNED WITH THE 850-700MB DEW POINT AXIS. THERE IS ALSO
THE INDICATION OF A MID LEVEL WAVE OVER FAR SOUTHWEST MN AS WELL.
SHORT TERM MODEL GUIDANCE PICKS UP ON THIS FEATURE AND DEEPENS IT
INTO A CLOSED LOW NEAR KDLH OVERNIGHT. THINKING IS THAT SHOWERS AND
THUNDERSTORMS WILL CONTINUE IN THE MOIST PLUME AS WELL AS
INCREASE IN COVERAGE AND INTENSITY TO THE NORTH AND EAST OF THE
TWIN CITIES. THEREFORE...EXPANDED THE FLOOD WATCH INTO WEST
CENTRAL WI AND TO THE NORTH OF THE TWIN CITIES INTO SUNDAY
MORNING.

DRYING SHOULD HAVE SPREAD INTO EASTERN MN BY SUNDAY MORNING IN THE
WAKE OF THE LOW/TROF WITH THE THREAT FOR RAIN ENDING OVER WEST
CENTRAL WI BY AFTERNOON. THE DRY PERIOD WILL LAST SUNDAY NIGHT
ACROSS WI BUT SHOWERS AND THUNDERSTORM CHANCES WILL BE ON THE
INCREASE ACROSS THE MN CWA AS A MASSIVE STORM SYSTEM IN THE
ROCKIES BEGINS TO MOVE SLOWLY EAST. GFS/ECMWF ARE IN PRETTY GOOD
AGREEMENT ON THE FORWARD SPEED ON THIS SYSTEM...BRINGING A 995MB
LOW INTO SW MN BY TUESDAY EVENING. DIVERGENCE THEN SETS IN BEYOND
THIS PERIOD AS THE GFS AND ECMWF GO OPPOSITE DIRECTIONS WITH THE
UPPER LOW. PREEPD INDICATED THAT THE ECMWF SOLUTION BEYOND TUESDAY
WAS SUSPECT. SHOWERS AND THUNDERSTORMS WILL BE A COMMON THEME IN
THE FORECAST FROM MONDAY THROUGH TUESDAY NIGHT. SOUTHERN MN AND
ADJOINING AREAS OF WI WILL BE MOST VULNERABLE FOR ALL FORMS OF
SEVERE WEATHER. ANOTHER CONCERN WILL BE THE FLOODING
POTENTIAL WITH SOUTHERN MN IN THE HOT SEAT ONCE AGAIN AS PW'S POOL
INTO THE 1.6 TO 1.9 INCH RANGE WHICH IS AT OR ABOVE 2 STANDARD
DEVIATIONS.

WEDNESDAY SHOULD HAVE PLENTY OF SHOWERS WITH ISOLATED
THUNDERSTORMS WITH A SLOW DRYING TREND OCCURRING FROM WEST TO EAST
ON THURSDAY. ACTUALLY ENDED THE FORECAST WITH DRY WEATHER FOR
FRIDAY AND SATURDAY.

&&

.AVIATION... /18Z TAF ISSUANCE/

NOT A STRAIGHTFORWARD SCENARIO WITH WEAK BOUNDARY EXTENDING FROM
SOUTH CENTRAL MN TO CENTRAL MN. BOUNDARY SEEMS TO BE JUST EAST OF
KMKT AND JUST WEST OF KSTC AND KBRD. MAY BE A SURFACE LOW WEST OF
MSP AS WELL. MEANWHILE A SWATH OF MID AND UPPER MOISTURE HAS BEEN
EMANATING NORTHWARD FROM IOWA STORMS AND THIS IS WHERE STORMS HAVE
DEVELOPED. THERE IS SOME NORTHWEST DRIFT TO THIS FEATURE WHICH
WILL MOVE ACROSS THE MSP METRO AND MAY EVEN REACH KSTC. HAVE KEPT
THUNDER OUT OF OTHER SITES FOR NOW BUT DO BRING IN SHOWERS WITH
SHORT WAVE. OTHER CONCERN WILL BE POTENTIAL FOR IFR LATE TONIGHT
ESPECIALLY AT AXN/RWF/STC AND POSSIBLY MSP. LIGHT WINDS WITH
DECAYING BOUNDARY AND ABUNDANT LOW LEVEL MOISTURE MAY WELL HELP
IFR DEVELOP. CONFIDENCE WAS HIGH ENOUGH TO ADD IFR CIGS TO AXN AND
STC LATE TONIGHT BUT KEPT CIGS MVFR AT ALL OTHER TAF SITES.

KMSP...THUNDERSTORMS SPREADING AND DEVELOPING TO THE NORTH-
NORTHWEST AND WILL AFFECT KMSP THROUGH ABOUT 19Z AND MAYBE 20Z.
MANY OF THEM HAVE BEEN TORRENTIAL RAINFALL PRODUCERS AND HAVE
DROPPED VSBY TO 1.5 MILES IN TEMPO GROUP. VSBY MIGHT GO LOWER FOR A
SHORT WHILE. OTHERWISE... HAVE INDICATED SHOWERS LATE THIS
AFTERNOON AND EVENING AS THE LIKELY LOCATION OF NEXT BATCH OF STORMS
IS NOT YET APPARENT. LIGHT WINDS LATER TONIGHT AND LOW LEVEL
MOISTURE WILL LEAD TO MVFR CEILINGS LATE TONIGHT INTO SUNDAY MORNING.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR ANOKA-BLUE EARTH-
     BROWN-CARVER-DAKOTA-FARIBAULT-HENNEPIN-LE SUEUR-MARTIN-
     NICOLLET-RAMSEY-RICE-SCOTT-SIBLEY-WASECA-WASHINGTON-
     WATONWAN.

     FLOOD WATCH THROUGH SUNDAY MORNING FOR CHISAGO-ISANTI-KANABEC.

WI...FLOOD WATCH THROUGH SUNDAY MORNING FOR BARRON-DUNN-POLK-RUSK-ST.
     CROIX.

&&

RAH/TDK

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1212 PM CDT SAT JUN 18 2011

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
191100-
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-
1212 PM CDT SAT JUN 18 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL BE POSSIBLE ALONG AND EAST OF A WEAK FRONT OVER
CENTRAL AND EASTERN MINNESOTA. HEAVY RAIN IS POSSIBLE THIS
AFTERNOON AND TONIGHT OVER CENTRAL AND EASTERN MINNESOTA INTO
WISCONSIN. A FEW STORMS COULD ALSO BE STRONG OR SEVERE WITH LARGE
HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS WILL REMAIN POSSIBLE SUNDAY MORNING ACROSS EAST
CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. STRONG TO SEVERE
THUNDERSTORM CHANCES WILL INCREASE AGAIN MONDAY AND TUESDAY AS A
STRONG AREA OF LOW PRESSURE TRACKS NEAR THE MINNESOTA IOWA BORDER.
TORRENTIAL RAIN WILL ALSO ACCOMPANY THE STORMS.

.SPOTTER INFORMATION STATEMENT...

THERE IS A SMALL CHANCE THAT SKYWARN SPOTTER ACTIVATION MAY BE
NEEDED THIS AFTERNOON AND TONIGHT.