Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KARX 182049
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
349 PM CDT SAT APR 18 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 348 PM CDT SAT APR 18 2015

AT 3 PM...A BACKDOOR COLD FRONT WAS LOCATED FROM MANKATO MINNESOTA
TO DUBUQUE IOWA. EAST WINDS IN THE WAKE OF THIS FRONT HAS BROUGHT
DRY DEW POINTS INTO THE AREA. THESE DEW POINTS RANGE FROM THE MID
20S TO LOWER 40S. THE DEW POINTS ARE SLOWING THE NORTHEAST
PROGRESS OF THE LOWER CLOUDS AND PRECIPITATION INTO SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON.

FOR TONIGHT...THE 18.12Z MODELS SHOW THAT THE INVERTED TROUGH
EXTENDING FROM WESTERN IOWA NORTHEAST INTO THE DAKOTAS WILL MOVE
SLOWLY NORTHEAST TONIGHT. AS THIS OCCURS...THE LOW LEVEL MOISTURE
WILL SLOWLY CLIMB INTO 50S ACROSS NORTHEAST IOWA AND SOUTHEAST
MINNESOTA. IN ADDITION...THE 700 TO 500 MB FRONTOGENESIS
WILL GRADUALLY INCREASE ACROSS THE AREA. AS THIS OCCURS...A BAND
OF SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE INTO THESE AREAS.
MEANWHILE THE DRY AIR WILL KEEP WESTERN WISCONSIN MAINLY DRY...SO
LOWERED OR TOOK OUT THE PRECIPITATION CHANCES FOR THIS AREA.

ON SUNDAY...THE 700 TO 500 MB FRONTOGENESIS WILL MOVE SLOWLY EAST
ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THIS WILL CONTINUE
TO BE THE MAIN FOCUS FOR THE PRECIPITATION ACROSS THE AREA.
MEANWHILE THERE IS CONTINUAL CONCERN THAT THE DRY FLOW AND
SUBSIDENCE AHEAD OF THIS SYSTEM WILL KEEP WESTERN WISCONSIN DRY
DURING THE MORNING. DUE TO THIS CONCERN...LOWERED THE
PRECIPITATION CHANCES SOME. IF THE ARW AND NMM IS CORRECT...THESE
AREAS MAY REMAIN DRY UNTIL MID AFTERNOON. THE PRECIPITATION
CHANCES ACROSS THE ENTIRE AREA WILL INCREASE ON SUNDAY AFTERNOON
AS THE DEFORMATION PRECIPITATION ASSOCIATED WITH A SHORT WAVE
TROUGH MOVES NORTHEAST FROM ILLINOIS INTO LOWER MICHIGAN AND THE
700 AND 500 MB FRONTOGENESIS CONTINUES TO MOVE EAST INTO WESTERN
WISCONSIN.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 348 PM CDT SAT APR 18 2015

ON SUNDAY NIGHT...MANY OF THE DETERMINISTIC MODELS CONTINUE TO SHOW
THAT A STRONG 900 TO 500 MB FRONTOGENETIC BAND WILL MOVE EAST
THROUGH WISCONSIN. THERE CONTINUES TO BE STEEP LAPSE RATES BETWEEN
850 AND 800 MB LAYER IN THE WAKE OF THE SYSTEM. HOWEVER THE
SOUNDINGS ARE SUGGESTING THAT THE DEPTH OF THE MOISTURE MAY BECOME
A CONCERN...SO WE MAY BE HOLDING ON TO THE 20 TO 40 PERCENT
PRECIPITATION CHANCES TOO LONG.

ON MONDAY AND MONDAY NIGHT...VERY STEEP LAPSE RATES DEVELOP FROM
900 TO 700 MB. THIS WILL LIKELY RESULT IN THE DEVELOPMENT OF
SHOWERS. THE WIND GUSTS MAY EVEN GUST UP TO 30 MPH DURING THE
AFTERNOON AND EVENING. AS TEMPERATURES COOL ON MONDAY NIGHT...
THERE MAY BE EVEN SOME SNOW MIXING IN AT TIMES MAINLY NORTH OF
INTERSTATE 94.  IF IT DOES...NOT EXPECTING ANY ACCUMULATION.

FOR THE REMAINDER OF THE WEEK...THE UPPER LEVEL LOW WILL REMAIN IN
PLACE ACROSS THE GREAT LAKES AND EASTERN CANADA. THIS IS DUE TO
STRONG RIDGING ACROSS THE EASTERN ATLANTIC AND GREENLAND. THE
CYCLONIC FLOW WILL CONTINUE TO REINFORCE THE COOL CANADIAN AIR
ACROSS THE REGION. AS A RESULT...HIGHS WILL REMAIN MAINLY IN THE
40S AND 50S. LOW TEMPERATURES WILL RANGE FROM THE UPPER 20S TO
UPPER 30S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY NIGHT)
ISSUED AT 1130 AM CDT SAT APR 18 2015

CIGS...
HIGH...MOSTLY THIN CLOUDS FILTERING IN FROM THE SOUTHWEST
THIS AFTERNOON...WILL GRADUALLY LOWER AND THICKEN THIS
EVENING/OVERNIGHT AHEAD OF AN APPROACHING UPPER LEVEL TROUGH. COULD
SEE SOME MVFR CIGS AT KRST SUN MORNING AS ASSOCIATED COLD FRONT
MOVES IN. KLSE WILL LIKELY HOLD VFR THROUGH THE FORECAST
PERIOD...ALTHOUGH A FEW HOURS OF MVFR CAN/T BE RULED OUT AS THE
FRONT APPROACHES.

WINDS...
EASTERLY FETCH TODAY INTO TONIGHT...GRADUALLY BECOMING SOUTHERLY ON
SUNDAY AS THE COLD FRONT APPROACHES. MIXING WILL RESULT IN SOME +20
KT GUSTS THIS AFTERNOON...WITH SUSTAINED HOLDING NEAR 10 KTS THROUGH
TONIGHT.

WX/VSBY...
-SHRA AND A FEW TS ONGOING OVER IOWA...BUT WILL HAVE TO BATTLE A LOT
OF LOW LEVEL DRY AIR ACROSS WI BEFORE IT CAN MAKE MUCH PROGRESS
EAST. MODEL TRENDS OVER THE PAST COUPLE DAYS HAVE BEEN TO SLOW THE
PCPN/S EASTWARD PUSH...AND THIS LOOKS VALID. GOING TO STICK WITH
VCSH AT KLSE FOR NOW...WITH CONFIDENCE SHAKY ON WHETHER THERE WILL
BE A PERIOD OF SHRA BEFORE THE FRONT GETS IN. HIGHER LIKELIHOOD FOR
KRST. A DROP INTO MVFR VSBYS WITH THE SHRA POSSIBLE.

&&

.FIRE WEATHER...THIS EVENING
ISSUED AT 348 PM CDT SAT APR 18 2015

A BACK DOOR COLD FRONT MOVED THROUGH MUCH OF THE AREA THIS
MORNING. THIS BROUGHT VERY DRY AIR INTO WESTERN WISCONSIN...AND
PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THE LOWEST DEW
POINTS ARE FOUND ACROSS CENTRAL WISCONSIN /MID 20S/. THE
COMBINATION OF THESE DEW POINTS AND TEMPERATURES IN THE MID AND
UPPER 60S PRODUCED RELATIVE HUMIDITIES IN THE LOWER AND MID 20S
THIS AFTERNOON. IN ADDITION...THERE IS AN EAST WIND SUSTAINED IN
THE 15 TO 20 MPH RANGE WITH WIND GUSTS UP TO 25 MPH. THE LATEST...
CANADIAN FOREST FIRE DANGER RATING SYSTEM IS IN THE VERY HIGH
RANGE /LOWER TO MID 90S/. THE HIGHEST VALUES ARE IN CENTRAL
WISCONSIN. THE WISCONSIN DNR CURRENTLY HAS THE RED FLAG AREA OF
CENTRAL WISCONSIN IN EXTREME FIRE DANGER. MEANWHILE THE REMAINDER
OF THE AREA IS UNDER VERY HIGH DANGER. AS A RESULT...PEOPLE ARE
DISCOURAGED TO DO ANY OUTDOOR BURNING THIS EVENING. WITH THE WINDS
DECREASING TONIGHT AND DIURNAL COOLING...THE RELATIVE HUMIDITY
WILL INCREASE INTO THE 50S BY MID TO LATE EVENING. THIS WILL HELP
DECREASE THE THREAT OF FIRE SPREADING RAPIDLY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR WIZ034-042>044.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.......RIECK
FIRE WEATHER...BOYNE



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.