Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 300849
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
349 AM CDT THU JUL 30 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT THU JUL 30 2015

AT 3 AM...A 1022 MB HIGH CENTERED OVER NEBRASKA KEPT SKIES
CLEAR ACROSS THE UPPER MISSISSIPPI RIVER OVERNIGHT. TEMPERATURES
ALONG THE MISSISSIPPI RIVER RANGE FROM THE MID 60S TO LOWER 70S.
MEANWHILE ELSEWHERE TEMPERATURES RANGED FROM THE MID 50S TO
MID 60S. THE COOLEST READINGS WERE FOUND IN CENTRAL WISCONSIN.

FROM THIS AFTERNOON INTO THE EVENING...A SHORT WAVE
TROUGH...CURRENTLY LOCATED OVER MANITOBA...WILL MOVE SOUTHEAST
ACROSS NORTHERN AND EASTERN WISCONSIN. WITH SOUNDINGS SIMILAR TO
WEDNESDAY AFTERNOON...JUST CANNOT SEE THE LOWER TO MID 60 SURFACE
DEW POINTS THAT ARE SHOWING UP IN THE ARW AND NMM. AS A
RESULT...LOWERED THE DEW POINTS INTO THE LOWER AND MID 50S. THERE
MAY BE EVEN SOME UPPER 40 DEW POINTS IN CENTRAL WISCONSIN. BY
LOWERING THESE DEW POINTS...THE 1 TO 2K CAPES THAT ARE SHOWING UP
IN THE ARW AND NMM ARE VERY UNREALISTIC. THEY ARE MORE LIKELY IN
THE 500 TO 1000 J/KG. WITH SO MUCH LOWER INSTABILITY...WENT MORE
WITH RAP...NAM...ECMWF...AND GFS WHICH KEPT THE AREA DRY. IF A
SHOWER OR STORM DID HAPPEN TO DEVELOP IT WOULD...IT WOULD BE NORTH
OF INTERSTATE 94.

LIKE YESTERDAY...IT LOOKS LIKE WE WILL MIX UP TO 800 MB DURING THE
LATE MORNING AND AFTERNOON. THIS WILL ALLOW FOR OCCASIONAL WIND
GUSTS OF 20 TO 25 KNOTS. IN ADDITION WITH THE DRY AIR AND QUITE A BIT OF
SUNSHINE...RAISED THE MODEL CONSENSUS MAXIMUM TEMPERATURES BY 2 TO
4 DEGREES. THIS WOULD MAKE THEM RATHER SIMILAR TO THE HIGH
TEMPERATURES ON WEDNESDAY.

FOR TONIGHT...THE SOUNDINGS REMAIN VERY DRY IN THE BOUNDARY LAYER.
IN ADDITION...THERE IS ONLY A VERY SHALLOW LAYER OF LIGHT WINDS.
DUE TO THIS...NOT EXPECTING ANY VALLEY FOG DEVELOPMENT TONIGHT.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU JUL 30 2015

ON FRIDAY AFTERNOON AND EVENING...ANOTHER SHORT WAVE TROUGH WILL
MOVE THROUGH THE REGION. LIKE TODAY...THE MODEL DEW POINTS LOOK
TOO HIGH...SO LOWERED THEM INTO THE LOWER AND MID 50S. THIS WILL
LOWER THE SURFACE BASED CAPES BY 500 TO 1000 J/KG WHICH FITS WELL
WITH THE 500 TO 1000 J/KG 0-1 KM CAPES. WITH THE BEST FORCING AND
LIFT LOCATED OVER NORTHERN AND EASTERN WISCONSIN...KEPT THE
FORECAST DRY. IN ADDITION WITH THE DRY AIR AND QUITE A BIT OF
SUNSHINE...RAISED THE MODEL CONSENSUS MAXIMUM TEMPERATURES BY 2 TO
4 DEGREES.

ON SATURDAY NIGHT...THE 30.00Z MODELS CONTINUE TO BRING A SLIGHTLY
STRONGER SHORT WAVE TROUGH AND SURFACE COLD FRONT THROUGH THE
REGION. 0-1 KM CAPES AHEAD OF THIS SYSTEM RANGE FROM 750 TO
1500 J/KG. DURING THE LATE AFTERNOON AND EARLY EVENING...THERE
LOOKS TO BE ENOUGH SHEAR FOR SOME SUPERCELLS INITIALLY...BUT WITH
MUCH OF THIS SHEAR LOCATED IN THE 0-3 KM LAYER...EXPECT THE STORMS
TO TRANSITION QUICKLY OVER TO A LINE OF STORMS. WITH THE
INSTABILITY BEING MAYBE TOO HIGH DUE TO THE POTENTIAL OF LOWER DEW
POINTS /SOME MODELS WERE SUGGESTING DEW POINTS AROUND 70
DEGREES/...LIKE THE MARGINAL RISK IN THE DAY 3 CONVECTIVE OUTLOOK.
IF SEVERE HAPPENS TO DEVELOP DAMAGING WINDS AND MAYBE SOME LARGE
HAIL WOULD BE THE PRIMARY THREATS.

ON SUNDAY NIGHT AND MONDAY...ANOTHER SHORT WAVE TROUGH AND
CANADIAN COLD FRONT WILL MOVE THROUGH THE REGION. THE 0-1 KM CAPES
AHEAD OF THIS SYSTEM WILL LIKELY RANGE BETWEEN 1 AND 2K AHEAD OF
THIS WAVE. THE BEST SHEAR WITH THIS SYSTEM LOCATED IN THE 0-3 KM
LAYER. LIKE SATURDAY NIGHT...EXPECT THE CONVECTION TO BE LINEAR
IN NATURE.

FROM MONDAY THROUGH WEDNESDAY...THE AREA WILL SEE 850 MB
TEMPERATURE 2 TO 4C COOLER THAN THE END OF THIS WEEK. THIS IS DUE
TO THE UPPER LEVEL RIDGE AMPLIFYING OVER THE INTERMOUNTAIN REGION.
HIGH TEMPERATURES DURING THIS PERIOD WILL LIKELY BE CONFINED TO
THE 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1151 PM CDT WED JUL 29 2015

SKIES ARE EXPECTED TO REMAIN CLEAR THROUGH THE PERIOD AS HIGH
PRESSURE DRIFTS SOUTHEAST FROM NEBRASKA INTO MISSOURI. THE WEST
WINDS WILL BECOME GUSTY AGAIN THURSDAY ONCE THE LOW LEVEL
INVERSION MIXES OUT. THE GUSTS THURSDAY SHOULD NOT BE AS HIGH AS
EXPERIENCED WEDNESDAY WITH SPEEDS TOPPING OUT BETWEEN 20 AND 25
KNOTS. THESE WINDS WILL SETTLE DOWN TO LESS THAN 10 KNOTS EARLY
THURSDAY EVENING ONCE THE INVERSION BEGINS TO FORM.


&&

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

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04



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