Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 100850
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
350 AM CDT THU APR 10 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT THU APR 10 2014

AT 3 AM...A COLD FRONT EXTENDED FROM MEDFORD WISCONSIN TO CHARLES
CITY IOWA. HOWEVER THE PRECIPITATION IS MUCH FURTHER NORTH ACROSS
EAST CENTRAL MINNESOTA AND NORTHERN WISCONSIN CLOSER TO THE UPPER
WAVE AND BEST FORCING.

THE COLD FRONT WILL MOVE SOUTH THROUGH NORTHEAST IOWA AND
SOUTHWEST WISCONSIN THIS MORNING. WHILE THE 900 TO 500 MB
FRONTOGENETIC FORCING REMAINS STRONG AS THE UPPER WAVE MOVES
SOUTHEAST THROUGH THE FORECAST AREA THIS MORNING...IT IS MOVING
INTO A PROGRESSIVE DRIER AIR MASS ALOFT. MANY OF THE MESO MODELS
ARE IN VERY GOOD AGREEMENT THAT THERE IS ONLY FEW TO SCATTERED
SHOWERS ASSOCIATED WITH THIS SHORT WAVES. DUE TO THIS...LOWERED
THE PRECIPITATION CHANCES. ALSO USED THE MESO MODELS TO ADD MORE
TIMING TO THEIR POSSIBILITY.

IN THE WAKE OF THIS SHORT WAVE THIS AFTERNOON...STRONG SUBSIDENCE
BELOW 500 MB DEVELOPS ACROSS THE AREA. BUFKIT MODEL SOUNDINGS
SUGGEST THAT WE WILL MIX UP INTO THE 600 TO 700 MB RANGE. HOWEVER
AT TIMES...THEY CAN BE TOO ROBUST...SO LIMITED THE MIXING UP TO
800 MB. THIS LOWERED THE SURFACE DEW POINTS TO AROUND 20 WHICH WAS
VERY SIMILAR TO WHAT OCCURRED ACROSS SASKATCHEWAN ON WEDNESDAY
AFTERNOON. WITH WEST TO NORTHWEST WINDS AROUND 15 KNOTS...RELATIVE
HUMIDITIES AROUND 20 PERCENT...AND DRY FUELS...WE WILL ONCE AGAIN
SEE CRITICAL FIRE WEATHER CONDITIONS. SERIOUSLY CONSIDERED A RED
FLAG WARNING...BUT OPTED NOT SINCE THE WINDS WILL BE DECREASING
DURING THE LATTER HALF OF THE AFTERNOON AS THE PRESSURE GRADIENT
RELAXES.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 350 AM CDT THU APR 10 2014

ON FRIDAY MORNING...A SHORT WAVE TROUGH WILL MOVE ACROSS MINNESOTA
AND WISCONSIN. 290 TO 300K ISENTROPIC LIFT CAUSES ENOUGH
SATURATION AHEAD OF THIS WAVE TO WARRANT SCATTERED SHOWERS. WITH
MOST UNSTABLE CAPES APPROACHING 200 J/KG ACROSS NORTH CENTRAL
WISCONSIN DURING THE AFTERNOON LEFT THE ISOLATED THUNDERSTORMS IN
THE FORECAST FOR THE AFTERNOON.

ON FRIDAY AFTERNOON...SUBSIDENCE IN THE WAKE OF THIS FRONT WILL
HELP TO LOWER DEW POINTS INTO THE MID 30S. WITH HIGH TEMPERATURES
IN THE 60S...RELATIVE HUMIDITY VALUE WILL FALL INTO THE 25 TO
35 PERCENT RANGE. WEST WINDS OF AROUND 15 KNOTS WILL ALLOW THE
FINE FUELS /GRASSES/ TO RAPIDLY DRY OUT. THIS COULD RESULT IN
ANOTHER AFTERNOON OF CRITICAL FIRE WEATHER CONDITIONS.

FROM SATURDAY THROUGH SUNDAY...THE ECMWF CONTINUES TO SHOW THAT A
COLD FRONT WILL MOVE SLOWLY SOUTH THROUGH THE FORECAST AREA.
MEANWHILE THE GFS CONTINUES TO BE VERY PROGRESSIVE WITH THIS
FRONT. THE MAIN DIFFERENCE IS HOW THEY HANDLE ANOTHER WAVE MOVING
ALONG THIS FRONT. SINCE EACH MODEL HAS DEVIATED VERY LITTLE IN
THEIR SCENARIOS OVER THE LAST COUPLE OF DAYS...OPTED TO STAY WITH
ECMWF WHICH USUALLY DOES BETTER DURING THESE TIME PERIODS. WITH
PRECIPITABLE WATER VALUE RANGING BETWEEN 1 AND 1.25 INCHES...THERE
WILL BE THE POTENTIAL FOR SOME PERIODS OF HEAVY RAIN. HOWEVER THE
850 MB MOISTURE TRANSPORT IS MORE PARALLEL WITH THE FRONT AND
THIS WILL LOWER THE CHANCES OF SEEING A LONG PROLONG PERIOD OF
HEAVY RAIN. AS A RESULT...ONLY EXPECTING AROUND 1 INCH OF RAIN
DURING THIS TIME PERIOD. WITH THIS PRECIPITATION SPREAD OUT OVER A
LONG PERIOD...THE THREAT FOR FLOODING LOOKS MINIMAL.

LOOKING AHEAD TO WEDNESDAY...THE GFS IS STARTING TO SHOW THE
POTENTIAL FOR A WINTRY MIX OF PRECIPITATION ALONG AND SOUTH OF THE
INTERSTATE 90 CORRIDOR. MEANWHILE THE ECMWF KEEPS THIS PERIOD DRY.
DUE THESE DIVERSE MODEL SOLUTIONS...OPTED TO JUST STAY WITH THE
MODEL CONSENSUS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1151 PM CDT WED APR 9 2014

FRONT MOVING RAPIDLY ACROSS MN AND WILL CROSS THE TAF LOCATIONS
OVERNIGHT. WIND WILL SWITCH TO THE NORTHWEST BEHIND IT. WILL BE A
LITTLE BIT BREEZY AGAIN TOMORROW...BUT NOT AS MUCH AS IT WAS
WEDNESDAY. OTHER CONCERN IS SHOWER CHANCES ALONG THE PASSING
FRONT. RADAR SHOWS SOME RETURNS...BUT NOT MUCH MAKING IT TO THE
GROUND. MAINTAINED THE VCSH IN THE TAFS...BUT NO MVFR RESTRICTION
ANTICIPATED.


&&

.FIRE WEATHER...
ISSUED AT 350 AM CDT THU APR 10 2014

CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THIS AFTERNOON AND
FRIDAY AFTERNOON.

FOR THIS AFTERNOON...MIX DOWN DEW POINTS FROM 800 MB DROP SURFACE
DEW POINTS DOWN TO AROUND 20. THESE DEW POINTS ARE VERY SIMILAR TO
WHAT WAS OBSERVED IN THE WAKE OF THE COLD FRONT ACROSS SOUTHERN
SASKATCHEWAN ON WEDNESDAY AFTERNOON. THIS WILL LOWER RELATIVE
HUMIDITY VALUES TO AROUND 20 PERCENT ALONG AND SOUTH OF INTERSTATE
90. CFFDS DATA WAS AROUND 90 ON WEDNESDAY AFTERNOON...AND THEY
SHOULD BE SIMILAR IF NOT A BIT HIGHER THIS AFTERNOON. THOUGHT
ABOUT ISSUING A RED FLAG WARNING...BUT THE PRESSURE GRADIENT
WEAKEN DURING THE LATTER HALF OF THE AFTERNOON...AND THIS WILL
GREATLY LIMITS THE TIME IN WHICH THE WINDS WILL REACH CRITERIA.

FOR FRIDAY AFTERNOON...WEST WINDS WILL CLIMB UP TO 15 KNOTS.
HOWEVER THE RELATIVE HUMIDITY VALUES ARE A BIT HIGHER IN THE 25 TO
35 PERCENT RANGE. THIS COULD RESULT IN ANOTHER DAY FOR CRITICAL
FIRE WEATHER CONDITIONS.

AS A RESULT...OUTDOOR BURNING SHOULD BE AVOIDED THIS AFTERNOON AND
FRIDAY AFTERNOON. CIGARETTE BUTTS SHOULD BE PLACED IN PROPER
CONTAINERS. ALSO BE BE VERY CAREFUL DRIVING OFF ROAD RECREATION
VEHICLES THROUGH GRASSY AREAS.

&&

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

$$

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



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