000
FXUS63 KARX 211204
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
704 AM CDT TUE MAY 21 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM CDT TUE MAY 21 2013

AT 345 AM...SHOWERS AND ISOLATED THUNDERSTORMS WERE FOUND ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS PRECIPITATION WAS
CONTINUING TO DEVELOP IN THE RIGHT ENTRANCE REGION OF A 110 KNOT
250 MB JET. THE 21.00Z MESO MODELS ARE IN VERY GOOD AGREEMENT THAT
THE PRECIPITATION WILL CONTINUE TO MOVE NORTHEAST AWAY FROM NORTH
CENTRAL WISCONSIN EARLY THIS MORNING. FURTHER TO THE WEST...A
CLOSED UPPER LEVEL LOW REMAINED OVER THE EASTERN DAKOTAS.

FOR TODAY...THE MESO MODELS ARE IN GOOD AGREEMENT THAT WEAK TO
MODERATE 900-700 MB FRONTOGENESIS WILL REMAIN ACROSS NORTHERN
WISCONSIN AND CENTRAL MINNESOTA. IN ADDITION...THE ML CAPE WILL BE
CLIMBING UP TO 500 J/KG FOR LATE THIS MORNING AND AFTERNOON. THIS
WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. WITH
0-3 KM AND 0-6 KM SHEAR GENERALLY LESS 25 KNOTS...NO SEVERE
WEATHER IS EXPECTED.

FOR TONIGHT...THE 900-700 MB FRONTOGENESIS WILL PROVIDE A CHANCE
OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUING NORTH OF THE
INTERSTATE 94 CORRIDOR. MEANWHILE WITH THE CLOSED LOW WILL
APPROACHING THE AREA FROM THE DAKOTAS...AND A SHORT WAVE
TROUGH...CURRENTLY OVER NEW MEXICO...MOVING NORTHEAST ACROSS
NORTHERN ILLINOIS AND SOUTHWEST WISCONSIN WILL RESULT IN ISOLATED
TO SCATTERED SHOWERS MOVING INTO THE REMAINDER OF THE FORECAST
AREA AFTER MIDNIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 358 AM CDT TUE MAY 21 2013

FROM WEDNESDAY INTO WEDNESDAY NIGHT...THE CLOSED LOW WILL OPEN UP
INTO AN OPEN WAVE AND MOVE EAST THROUGH THE FORECAST AREA. THIS
EVENTUALLY EVOLVED INTO A DEFORMATION BAND OF PRECIPITATION MOVING
EAST THROUGH THE FORECAST AREA. THE HIGHEST PRECIPITATION CHANCES
WILL LIKELY RUN FROM THE LATE MORNING INTO THE EARLY EVENING. WITH
BOTH THE 0-3 KM AND 0-6 KM SHEAR LESS THAN 25 KNOTS...NONE OF THE
THUNDERSTORMS ARE EXPECTED TO BECOME SEVERE.

ON THURSDAY NIGHT...A CANADIAN HIGH PRESSURE SYSTEM WILL USHER IN
DEW POINTS OF AROUND 30 DEGREES INTO CENTRAL AND NORTH CENTRAL
WISCONSIN. IN ADDITION...THE CLEAR SKIES AND LIGHT WINDS WILL
ALLOW FOR VERY GOOD RADIATIVE COOLING. LOW TEMPERATURES ON FRIDAY
MORNING WILL LIKELY FALL INTO THE MID 30S ACROSS THIS REGION.
THERE EVEN COULD BE SOME LOWER 30S IN THE CRANBERRY BOGS OF
CENTRAL WISCONSIN. DUE TO THIS ADDED SOME PATCHY FROST INTO THE
FORECAST FOR THESE AREAS.

ON FRIDAY NIGHT AND SATURDAY MORNING...MODERATE WARM AIR ADVECTION
AND ISENTROPIC LIFT WILL DEVELOP ACROSS SOUTHEAST MINNESOTA...
NORTHEAST IOWA...AND WESTERN WISCONSIN. THIS IS IN RESPONSE TO THE
UPPER LEVEL RIDGE BUILDING TOWARD THE AREA. IN ADDITION...WEAK TO
MODERATE 850 MB MOISTURE TRANSPORT WILL LIKELY RESULT IN THE
DEVELOPMENT OF A MESOSCALE CONVECTIVE COMPLEX ACROSS NORTHWEST
MINNESOTA DURING THE EVENING AND THEN THE SYSTEM WILL MOVE
SOUTHEAST THROUGH OUR AREA FROM THE LATE EVENING INTO SATURDAY
MORNING. WITH PRECIPITABLE WATER VALUES RUNNING AROUND 1.2
INCHES...THERE COULD POTENTIALLY BE SOME BRIEF PERIODS OF HEAVY
RAIN WITH THIS COMPLEX. WHILE THE 0-6KM SHEAR REMAIN LESS THAN
30 KNOTS...THE 0-3KM SHEAR WILL BECOME FAVORABLE ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THAT THERE COULD POTENTIALLY BE A
WIND THREAT WITH THESE STORMS.

FROM SATURDAY THROUGH MEMORIAL DAY...THE MODELS CONTINUE TO DIFFER
ON THE LOCATION OF THE CANADIAN HIGH. THE ECMWF CONTINUES TO
SUGGEST THAT THE HIGH WILL KEEP THE AREA DRY THROUGHOUT THIS TIME
PERIOD. MEANWHILE THE GFS...CONTINUES TO KEEP THE HIGH MORE OVER
THE GREAT LAKES AND THIS KEEPS US IN THE ACTIVE AREA ON THE EAST
SIDE OF THE UPPER LEVEL RIDGE. SINCE BOTH MODELS HAVE CHANGED
LITTLE...DECIDED TO JUST STAY WITH THE ALL BLEND FOR NOW.

&&

.AVIATION...TODAY AND TONIGHT
704 AM CDT TUE MAY 21 2013

CENTER OF CLOSED SYSTEM NEAR WATERTOWN SD AND STARTING TO MAKE A
SLOW EASTWARD PUSH. ROTATION AROUND THE SYSTEM SENDING BANDS OF
CLOUD INTO THE TAF SITES. SOME OF IT IS MID CLOUD BUT ALSO SOME
MVFR CEILINGS IN THE 15-30KFT RANGE. ALSO SOME SPOTTY SHOWERS NOW
POPPING UP ON RADAR SINCE 1130Z. THESE LOOK TO MISS THE TAF
LOCATIONS FOR THE MOST PART...BUT IF EXPANSION CONTINUES MAY HAVE
TO AMEND TO ADD. OTHERWISE ANTICIPATE MVFR CEILINGS TO PREVAIL
THROUGH THE BULK OF THE DAY. TONIGHT...WITH A VERY MOIST BOUNDARY
LAYER...BROAD LIFT AND RECENT RAIN...EXPECT SOME LIGHT MIST/FOG
COULD BE AN ISSUE. ADDED MVFR BR TO THE TAFS...SUPPORTED BY THE
LATEST MOS GUIDANCE.

&&

.HYDROLOGY...
ISSUED AT 358 AM CDT TUE MAY 21 2013

RAINFALL ON WEDNESDAY AND WEDNESDAY EVENING WILL LIKELY BE LESS
THAN A QUARTER OF AN INCH ACROSS NORTHEAST IOWA AND SOUTHEAST
MINNESOTA. THIS RAINFALL WILL LIKELY JUST SLOW THE FALLS ON AREA
RIVERS AND STREAMS.

ON FRIDAY NIGHT AND SATURDAY...ANOTHER QUARTER TO HALF INCH OF
RAIN WILL LIKELY FALL ACROSS SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. LIKE WEDNESDAY...THIS RAIN WILL LIKELY ONLY SLOW THE FALL ON
AREA RIVERS AND STREAMS.

&&

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

&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...MW
HYDROLOGY...BOYNE