Areal Flood Advisory 7, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
613 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.../00Z TAF ISSUANCE/

MAIN AVIATION CONCERNS DEAL WITH EARLY EVENING CONVECTION...AND FG
DEVELOPING OVERNIGHT.

THERE REMAINS ENOUGH INSTABILITY ACROSS EASTERN MN/WESTERN WI TO
KEEP SHRA...WITH VCTS AT EAU/RNH. WILL HOLD OFF ON MSP DUE TO THE
BULK OF THE TSRA OVER WESTERN WI AT THIS TIME. AXN/RWF WILL BE VFR
FOR THE MOST PART DUE TO DRIER AIR NEAR THE SFC AND NOT A LOT OF
RAINFALL DURING THE LAST 12 HRS. ACROSS THE EAST...LOW CEILINGS
AND BR/FG ARE LIKELY OVERNIGHT. THE ONLY CONCERN IS CLD CVR WHICH
MAY HINDER EXTREMELY DENSE FG TO FORM. HOWEVER...MOST MODELS
AGREE THAT IFR/LIFR CEILINGS/VSBYS SHOULD DEVELOP AT
STC/MSP/RNH/EAU OVERNIGHT...ESPECIALLY TOWARD DAYBREAK AS WNDS
REMAIN LIGHT FROM THE SFC...UP TO 5K. WITH ABUNDANT MOISTURE
ARND...EXPECT THESE IFR/LIFR TO DEVELOP. TIMING WILL BE A CONCERN
IN THE SHORT TERM...SO WILL HOLD OFF UNTIL AFT 6Z...WITH THE BULK
OF THE IFR/LIFR CEILINGS/VBSYS AFT 9Z. AFT 13-15Z...CEILINGS/VSBYS
SHOULD BEGIN TO LIFT AS WNDS BECOME MORE EASTERLY DURING THE DAY.
MOST OF THE WET WEATHER SHOULD REMAIN TO THE FAR WEST UNTIL LATE
SUNDAY NIGHT/MONDAY MORNING.

MSP...IFR/MVFR CEILINGS IN THE SHORT TERM SHOULD MOVE OUT BEFORE
00Z TAF ISSUANCE. IN ADDITION...KEPT MOST OF THE TSRA/VCTS OUT OF
THE PICTURE THIS EVENING. HOWEVER...IT REMAINS CLOSE ENOUGH FOR
SOME CONCERN. WILL UPDATE TAFS IF NEEDED. AFT 3-4Z...MOST OF THE
LIFT SHOULD BE OFF TO THE EAST WITH CLDY SKIES AND CEILINGS/VSBYS
SLOWLY LOWERING. HAVE DROPPED CEILINGS/VSBYS FROM PREVIOUS
TAF...BUT AS STATED BEFORE...MOST MODELS CONTINUE THE TREND OF
IFR/LIFR CEILINGS/VSBYS DROPPING OVERNIGHT...AND WITH THE AMT OF
MOISTURE NEAR THE SFC/ALOFT AND A WEAK WND FIELD...I DO THINK
THERE WILL BE PROBLEMS AFT 6Z...AND ESPECIALLY TOWARD DAYBREAK.
WNDS WILL REMAIN LIGHT AND VARIABLE OVERNIGHT...WITH A EASTERLY
WND UNDER 8 KTS DEVELOPING AFT 15Z. ..JLT..

&&

.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/JLT

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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
400 PM CDT SAT JUN 18 2011

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

0357 PM     HAIL             1 SE RED WING           44.57N 92.59W
06/18/2011  M1.25 INCH       GOODHUE            MN   TRAINED SPOTTER

&&

AJZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
704 PM CDT SAT JUN 18 2011

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

0645 PM     HEAVY RAIN       4 NW ARKANSAW           44.67N 92.09W
06/18/2011  M1.51 INCH       PEPIN              WI   TRAINED SPOTTER

            RAINFALL OCCURRED IN JUST 50 MINUTES.

&&

AJZ