Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 160400
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1100 PM CDT WED APR 15 2015

.UPDATE...
ISSUED AT 803 PM CDT WED APR 15 2015

THE RED FLAG WARNING WAS ALLOWED TO EXPIRE AS SCHEDULED AT 8 PM.
TEMPERATURES WILL CONTINUE TO COOL THIS EVENING ALLOWING THE
HUMIDITY TO INCREASE. FOR THE MOST PART...THE WINDS HAVE ALREADY
DECREASED TO 10 MPH OR LESS AND WILL CONTINUE TO DIMINISH THROUGH
THE REST OF THE EVENING. ALL THIS WILL ALLOW THE THREAT FOR
WILDFIRES TO CONTINUE TO DIMINISH THIS EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 346 PM CDT WED APR 15 2015

AT 3 PM...THERE IS A TIGHT GRADIENT BETWEEN A 1031 MB SURFACE
HIGH OVER QUEBEC AND A LOW PRESSURE SYSTEM OVER EASTERN COLORADO.
THIS HAS RESULTED IN A SUSTAINED SOUTHEAST WIND OF 15 TO 25 MPH
WITH WIND GUSTS TO 30 MPH. WITH THE LOSS OF DIURNAL
HEATING...EXPECT THE WINDS TO QUICKLY SUBSIDE THIS EVENING AND
RELATIVE HUMIDITY VALUES TO CLIMB INTO THE 50S. THIS BRING AN END
TO OUR FIRE WEATHER CONCERNS.

ON THURSDAY...HIGH PRESSURE WILL CONTINUE TO PROVIDE DRY WEATHER
FOR THE AREA. WITH A BIT MORE SUNSHINE...TEMPERATURES SHOULD BE A
FEW DEGREES WARMER TOPPING OUT AROUND 70. SOUNDINGS SHOW THAT THE
WINDS BELOW 700 MB WILL BE 10 KNOTS OR LESS WHICH WILL GREATLY
LIMIT THE FIRE WEATHER CONCERNS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 PM CDT WED APR 15 2015

SATURDAY MAY BE ANOTHER SIGNIFICANT CONCERN FOR FIRE WEATHER
DEPENDING ON HOW MUCH OF AN EASTERLY WIND COMPONENT CAN DEVELOP
ACROSS THE AREA. GFS MODEL SOUNDINGS SHOW THAT THE AIR MASS BELOW
825 MB IS FAIRLY DRY. AS A RESULT...WILL HAVE TO WATCH THIS PERIOD
VERY CLOSELY AS WE MAY BE TOO HIGH WITH OUR DEW POINTS. IN
ADDITION...THE SOUNDINGS SHOW SUGGEST WIND GUSTS IN THE 20 TO
30 MPH RANGE. THIS SITUATION LOOKS SIMILAR TO THIS AFTERNOON...
SO WILL HAVE TO WATCH THIS PERIOD CLOSELY FOR THE POTENTIAL OF A
RED FLAG WARNING.

FROM SATURDAY NIGHT INTO SUNDAY...THE 15.12Z MODELS ARE
CONTINUING TO STRUGGLE WITH THE TIMING OF THE SHORT WAVE EJECTING
OUT OF THE FOUR CORNERS REGION. AS A RESULT...STAYED WITH THE
MODEL CONSENSUS AS FAR AS PRECIPITATION FOR THIS TIME PERIOD.
STILL NOT SEEING MUCH INSTABILITY FOR THIS TIME PERIOD...THUS...
JUST STAYED WITH RAIN SHOWERS. WITH CLOUDS AND PRECIPITATION
ACROSS THE AREA ON SUNDAY...IT DOES NOT APPEAR THAT WE WILL BE
WARMING UP THAT MUCH. THE ECMWF HAS ITS HIGH TEMPERATURES NEAR
50. MEANWHILE...THE MODEL BLEND HAS HIGHS IN THE MID AND UPPER
50S. WITH SUCH A DIFFERENCE...TOOK A 50 50 BLEND OF THE TWO FOR
THE HIGH TEMPERATURES FOR THIS TIME PERIOD.

FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT...MUCH COLDER AIR WILL
MOVE INTO THE REGION. THE GFS SOUNDINGS SUGGEST THAT THERE MAY BE
SOME ICE CRYSTAL SEEDING FROM ALOFT AND TEMPERATURES THROUGHOUT
THE COLUMN WILL BE BELOW FREEZING...SO INTRODUCED SOME SNOW
SHOWERS TO GO ALONG WITH THE RAIN SHOWERS FOR THIS TIME PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM CDT WED APR 15 2015

VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. A WEAK COLD FRONT
OVER THE DAKOTAS WILL BE ORIENTED EAST/WEST NORTH OF THE REGION
THURSDAY. THIS WILL ALLOW THE GRADIENT TO CONTINUE TO WEAKEN
OVERNIGHT AND BECOME VERY BAGGY THURSDAY. EXPECT THE WINDS TO
CONTINUE DIMINISHING AND BE LESS THAN 10 KNOTS THROUGH THE PERIOD.
ENOUGH OF A MOISTURE RETURN AHEAD OF THIS FRONT FOR SOME PERIODS
OF MID TO HIGH LEVEL VFR CEILINGS.

&&

.FIRE WEATHER...
ISSUED AT 346 PM CDT WED APR 15 2015

A VERY DRY SOUTHEAST FLOW WILL CONTINUE TO FLOW INTO THE AREA LATE
THIS AFTERNOON AND EVENING. AFTERNOON DEWPOINTS HAVE FALLEN INTO
THE 10 TO 30 DEGREE RANGE. THESE DEW POINTS ON TOP OF TEMPERATURES
IN THE MID AND UPPER 60S ARE PRODUCING VERY DRY RELATIVE HUMIDITY
VALUES OF 12 TO 26 PERCENT. IN ADDITION...THE SOUTHEAST WINDS ARE
GUSTING UP TO 25 MPH. THIS HAS RESULTED IN FINE FUEL MOISTURE
CODES IN THE LOWER AND MID 90S WHICH IS VERY HIGH. WITH ALL OF
THIS IN MIND...WILL KEEP THE RED FLAG WARNING GOING FOR SOUTHEAST
MINNESOTA AND WESTERN AND CENTRAL WISCONSIN THROUGH 8 PM THIS
EVENING. AFTER THAT TIME...THE RELATIVE HUMIDITIES WILL RISE INTO
THE 50S AND THE WINDS WILL SUBSIDE.

ON THURSDAY...THE WIND TRAJECTORY IS NOT BRINGING AS DRY AIR INTO
THE REGION AS THIS AFTERNOON. AS A RESULT...ONLY HAVE DEW POINTS
FALL INTO THE 25 TO 35 DEGREE RANGE WHICH IS 10 TO 15 DRIER THAN
ANY MODEL. THIS MAKES SENSE CONSIDERING THE SOUNDINGS ALOFT. WITH
HIGH TEMPERATURES AROUND 70...AFTERNOON RELATIVE HUMIDITY WILL
INTO THE 20 TO 35 PERCENT RANGE. WHILE IT IS DRY...THE WINDS ALOFT
WILL BE MUCH LIGHTER...THUS LIMITING THE FIRE WEATHER CONCERNS.

ON FRIDAY...A MORE SOUTHERLY TRAJECTORY WILL BRING A BIT MORE
MOISTURE INTO THE AREA WITH DEW POINTS RANGING FROM THE UPPER 30S
TO MID 40S. WITH TEMPERATURES IN THE LOWER AND MID 70S...AFTERNOON
RELATIVE HUMIDITY VALUES WILL FALL INTO 30S. IN ADDITION...THE
WINDS WILL REMAIN LESS THAN 15 MPH.

SATURDAY MAY BE ANOTHER SIGNIFICANT CONCERN FOR FIRE WEATHER
DEPENDING ON HOW MUCH OF AN EASTERLY WIND COMPONENT CAN DEVELOP
ACROSS THE AREA. GFS MODEL SOUNDINGS SHOW THAT THE AIR MASS BELOW
825 MB IS FAIRLY DRY. AS A RESULT...WILL HAVE TO WATCH THIS PERIOD
VERY CLOSELY AS WE MAY BE TOO HIGH WITH OUR DEW POINTS. IN
ADDITION...THE SOUNDINGS SHOW SUGGEST WIND GUSTS IN THE 20 TO
30 MPH RANGE. THIS SITUATION LOOKS SIMILAR TO THIS AFTERNOON...
SO WILL HAVE TO WATCH THIS PERIOD CLOSELY FOR THE POTENTIAL OF A
RED FLAG WARNING.

&&

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

$$

UPDATE...04
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
FIRE WEATHER...BOYNE



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