Areal Flood Warning 3, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
514 AM CST SAT MAR 13 2010

.UPDATE...
UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.

&&

.DISCUSSION...

MAIN FORECAST CONCERNS DEAL WITH ANY ADDITIONAL QPF AS THE MAIN
STORM SYSTEM THAT HAS BEEN AFFECTING OUR REGION DRIFTS S/SE ACROSS
THE DEEP SOUTHEAST U.S. OVER THE NEXT SEVERAL DAYS.

REGIONAL WV IMAGERY INDICATED A LARGE PLUME OF MOISTURE ADVECTING
W/NW ACROSS THE SOUTHERN GREAT LAKES EARLY THIS MORNING.
YESTERDAYS WEAK SHORT WAVE HAS NEARLY SHEARED OUT ACROSS FAR
WESTERN MN WHICH PRODUCED ONE QUARTER TO ONE HALF INCH OF RAINFALL
IN THE MISSISSIPPI AND MINNESOTA RIVER VALLEYS. HOWEVER...REMNANTS
OF THIS WAVE...COMBINED WITH ANOTHER SHORT WAVE DIVING SE ACROSS
THE NORTHERN PLAINS LATE IN THE WEEKEND/EARLY NEXT WEEK...MAY AID
IN WEAK LIFT AND PROVIDE FOR SOME LIGHT SHOWER ACTIVITY.
HOWEVER...CONFIDENCE REMAINS TOO LOW FOR ANYTHING OTHER THAN
20/30% AT THIS TIME.

BEST PRECIPITATION CHANCES WILL BE ASSOCIATED WITH A WEAK SYSTEM
ACROSS THE SOUTHERN GREAT LAKES WHICH MAY AFFECT FAR SE FA LATER
TODAY/TONIGHT. ELSEWHERE...DEEP MOISTURE IN THE FIRST 3000 FEET
SHOULD AID IN THE GENERATION OF PATCHY DRIZZLE/FG OR SPRINKLES AT
BEST.

BY MIDWEEK...A LARGE RIDGE BUILDING ACROSS THE UPPER MIDWEST SHOULD
ERODE MOST OF THE DEEP MOISTURE THAT HAS BEEN PLAGUING THE REGION FOR
THE PAST WEEK. SOME PARTIAL SUNSHINE IS LIKELY BY WEDNESDAY...BUT
CHANGES ARE EXPECTED BY THE END OF NEXT WEEK AS MEDIUM RANGE
MODELS INDICATED A LARGE STORM SYSTEM DEVELOPING IN THE MIDWEST.
BEHIND THIS SYSTEM...A COLDER WEATHER PATTERN WILL DEVELOP AND MAY
LAST THROUGH THE END OF MARCH. ..JLT..

&&

.AVIATION.../12Z TAF ISSUANCE/
NOT MUCH NEW TO SAY WITH REGARD TO AVIATION CONDITIONS ACROSS THE
AREA. WEAK CYCLONIC FLOW... ABUNDANT LOW LEVEL MOISTURE... AND
PERIODIC LOBES OF VORTICITY WILL CONTINUE TO IMPACT THE AREA
THROUGH THE UPCOMING 24 HOURS. WILL SEE THE DIURNAL IMPROVEMENT IN
VISIBILITIES AND CEILINGS AS THE BOUNDARY LAYER WARMS A BIT...
ALLOWING FOR NEAR SURFACE DEWPOINT DEPRESSIONS TO INCREASE AND
MIXING LAYER HEIGHTS TO RISE SLIGHTLY. BUT... THINGS WILL REVERSE
AGAIN TONIGHT AND CONDITIONS WILL WORSEN ONCE AGAIN. EVEN DURING
THE IMPROVEMENT PERIOD TODAY... NOT MUCH IN THE WAY OF IMPROVEMENT
IS EXPECTED... WITH THINGS GENERALLY IN LINE WITH HOW THEY HAVE
BEEN THE PAST FEW DAYS. MAY SEE SOME CEILINGS NEAR 1500FT AGL THIS
AFTERNOON... PARTICULARLY ACROSS THE EAST... AND VISIBILITIES
SHOULD CLIMB TO AOA 5SM. BUT... LOOK FOR THINGS TO TREND DOWNHILL
AGAIN TONIGHT... ALTHOUGH PERHAPS NOT QUITE AS LOW FOR CEILINGS OR
VISIBILITIES SINCE IT DOES APPEAR THAT A LITTLE DRY AIR WILL START
WORKING ITS WAY IN FROM THE NORTHEAST.

KMSP... FORECAST CONDITIONS CAPTURE EXPECTATIONS WITH MAIN
UNCERTAINTY BEING THE POSSIBILITY FOR A BRIEF WINDOW OF LOWER
VISIBILITIES DURING THE FIRST FEW HOURS OF THE TAF... AND THE
DEGREE TO WHICH CEILINGS RISE THIS AFTERNOON. FOR NOW... WILL BE A
BIT PESSIMISTIC WITH THIS AFTERNOON/S CEILINGS AND KEEP THEM AOB
1500 FT AGL... BUT IF TEMPERATURES CAN WARM ENOUGH THEN WE COULD
SEE CEILINGS GET A LITTLE ABOVE 1700FT AGL DURING THE AFTERNOON
FOR A TIME.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BLUE EARTH-
     BROWN-CARVER-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-GOODHUE-
     KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-
     NICOLLET-POPE-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-STEARNS-
     STEELE-STEVENS-SWIFT-TODD-WASECA-WATONWAN-WRIGHT-YELLOW
     MEDICINE.

WI...NONE.
&&

TRH/JLT/TRH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
410 AM CST SAT MAR 13 2010

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
141015-
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-
410 AM CST SAT MAR 13 2010

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

.DAY ONE...TODAY AND TONIGHT

AREAS OF DENSE FOG WILL CONTINUE THROUGH MID MORNING ACROSS A
LARGE AREA OF SOUTHERN AND WESTERN MINNESOTA. EXPECT CONDITIONS TO
SLOWLY IMPROVE BY NOON.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

RUNOFF FROM LAST WEEKS PRECIPITATION AND MELTING SNOW WILL
CONTINUE TO FILTER INTO AREAS STREAMS AND CREEKS. THIS WILL ALLOW
FOR THE CONTINUATION OF AREA RIVERS TO RISE OVER THE NEXT WEEK.

PLEASE REFER TO THE LATEST RIVER FLOOD WATCHES AND WARNINGS
ACROSS MINNESOTA FOR MORE INFORMATION.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

JLT