Areal Flood Warning 11, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
129 PM CDT WED APR 13 2011

.DISCUSSION...

MINOR ADJUSTMENTS WERE MADE IN THE SHORT TERM FORECAST AS MID
LEVEL FRONTOGENESIS WILL AID IN THE DEVELOPMENT OF SCATTERED SHRA
ACROSS THE SOUTHERN 2/3 OF THE FA TODAY. DEPENDING UPON SHORT TERM
TRENDS OF THE REGIONAL RADAR...MAY ADJUST POPS TO LIKELY OR
CATEGORICAL.

MAIN FORECAST CONCERN REMAINS WITH THE SYSTEM ON THU/FRI AND EARLY
SAT. PREVIOUS FORECAST ON TRENDING THE POPS TO A MORE SW TO NE
ORIENTATION OF THE HIGHER POPS /HIGHER TO THE SW/ SEEMS REASONABLE
DUE TO THE ANTICIPATED DRY AIR MASS INTRUSION ONCE TODAYS FRONTAL
BOUNDARY MOVES SOUTH OF THE STATE.

ALTHOUGH THERE REMAINS SOME MINOR FLUCTUATIONS TO THE SFC AND
UPPER LEVEL FEATURES WITH THIS SYSTEM...THE GENERAL SCENARIO
REMAINS GOOD FOR A WIDESPREAD PRECIPITATION EVENT FOR MAINLY THE
SW ONE HALF OF THE FORECAST AREA FOR LATE THU/FRI...THEN SLOWLY
SPREADING NORTH AND EAST BY FRIDAY NIGHT.

AS DEPICTED BY THE LATEST WX MODELS...STRONG WAA IS EXPECTED ON
THE EAST SIDE OF THIS STORM SYSTEM FOR THU NIGHT/FRIDAY. MOST OF
THE PRECIPITATION WILL BE IN THE FORM OF RAIN...WITH SOME MIXTURE
OF SNOW ALONG THE SD BORDER...AND DURING THE ONSET OF THE
PRECIPITATION ACROSS THE CENTRAL PART OF THE STATE ON FRIDAY. THE
MAIN HEAVY BANDS OF SNOWFALL WILL REMAIN IN SD UNTIL THE SFC LOW
MOVES TO THE EAST...AND BEGINS TO SPREAD COLDER AIR INTO THE AREA
LATE FRIDAY AFTN/EVENING.

AT THIS TIME...THE POSSIBILITY OF SEVERAL INCHES OF SNOW COULD
FALL IN PORTIONS OF WC AND SW MN FRIDAY EVENING...BEFORE THE MAIN
PRECIPITATION BANDS MOVE EAST OF THE AREA. SNOWFALL ACCUMULATIONS
FOR THE REST OF THE FA WILL BE HIGHLY DEPENDENT ON WHEN THE CHG
OVER TO SNOW BEGINS FRIDAY EVENING...AND WHEN THE MAIN FORCING
LEAVES THE AREA OR AS THE PRECIPITATION BANDS BEGIN TO DISSIPATE.
SEVERAL SCENARIOS BASED ON THE CURRENT MODEL RUNS HAVE SOME
ACCUMULATIONS ACROSS THE FA BY SATURDAY MORNING. THE LATEST GFS
HAS THE LEAST AMTS BASED ON THE CURRENT TRACK OF THE SFC LOW AND
SPEED OF WHICH THIS SYSTEM DEPARTS BY SATURDAY MORNING.
HOWEVER...THE GEM AND THE EC KEEP SOME TYPE OF RESIDUAL MOISTURE
AND LIFT SATURDAY...WHICH LEADS TO MORE SNOWFALL. THE BEST BET IS
TO SEE HOW THE SYSTEM BEGINS TO EVOLVE ONCE IT MOVES OUT OF THE
ROCKIES THURSDAY...AND HOW MUCH DRIER AIR HAS MANAGE TO MOVE
SOUTHWARD ACROSS MN/WI WITH TODAYS SYSTEM.

ONE ITEM TO NOTE...THIS SYSTEM IS VERY DYNAMIC WHICH WILL LEAD TO
WINDY CONDITIONS. THE EXTENDED PERIOD REMAINS THE SAME WITH A
COOLER PATTERN EXPECTED THRU EARLY NEXT WEEK. ..JLT..

&&

.AVIATION.../18Z TAF ISSUANCE/

NORTHERLY SURFACE WINDS CONTINUE ACROSS THE AREA BEHIND A COLD
FRONT WHICH PASSED EARLIER. AN UPPER LEVEL FRONT REMAINS VERY SLOW
TO MOVE ACROSS SOUTHERN MN INTO WESTERN WI. ALONG THIS IS LIGHT
RAIN SOME OF WHICH IS MORE SHOWERY AT TIMES. THIS IS MAINLY GOING
TO OCCUR AT RWF...BUT WILL COME CLOSE TO MSP AND EAU. THE FRONT
WILL MOVE TO THE SOUTHEAST BY LATE EVENING...ENDING THE RAIN
CHANCES FOR THE REMAINDER OF THE NIGHT AND INTO THURSDAY MORNING.
MID TO UPPER LEVEL CLOUD COVER WILL LINGER...WITH SOME 3-6K FT
CEILINGS ACROSS SOUTHERN MN...POTENTIALLY NEAR RWF DURING THE
MORNING. NORTHERLY WINDS WILL HAVE SOME GUSTS THIS
AFTERNOON...ESPECIALLY AT CENTRAL MN SITES WHERE MORE SUN HAS
ALLOWED FOR FURTHER MIXING. THE WIND DIRECTION WILL VEER
TONIGHT...BECOMING EAST BY DAYBREAK. THE WIND SPEED WILL INCREASE
WITH GUSTS NEAR 20 KTS LIKELY NEAR NOON.

MSP...THE LIGHT RAIN WILL COME CLOSE TO THE AIRPORT LATE THIS
AFTERNOON...BUT NOT EXPECTING IT TO REACH THE FIELD. THE WIND
DIRECTION SHOULD STAY BETWEEN 340 AND 020 THROUGH EARLY EVENING.
THEN VEERING WILL OCCUR TONIGHT...WITH WINDS EAST NORTHEAST BY
DAYBREAK. THE DIRECTION TOMORROW MORNING IS EXPECTED TO BE CLOSER
TO EAST THAN NORTH...WITH SPEEDS INCREASING TO NEAR 15 KTS.

&&

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

&&

JLT/MTF

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1211 PM CDT WED APR 13 2011

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
141200-
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-
1211 PM CDT WED APR 13 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

MANY RIVERS AND THEIR TRIBUTARIES REMAIN IN FLOOD. PLEASE
CONTINUE TO MONITOR FLOOD STATEMENTS FOR THE LATEST UPDATES.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A STORM SYSTEM WILL AFFECT THE UPPER MIDWEST FRIDAY AND SATURDAY.
SOME LATE SEASON ACCUMULATING SNOWFALL IS LIKELY BEFORE THE SYSTEM
DEPARTS THE AREA SATURDAY. CONTINUE TO MONITOR LATER OUTLOOKS FOR
ADDITIONAL DETAILS.

RIVERS WILL LIKELY REMAIN IN FLOOD THROUGH NEXT WEEK. CONTINUE TO
MONITOR FLOOD STATEMENTS FOR THE LATEST UPDATES.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.