Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 040443
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1143 PM CDT MON AUG 3 2015

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 220 PM CDT MON AUG 3 2015

QUIET CONDITIONS INTO WEDNESDAY AS HIGH PRESSURE WORKS OVERHEAD. THE
EXPECTED CLEAR NIGHTS AND LIGHTER WIND FIELD SETS THE STAGE FOR FOG
IN THE RIVER VALLEYS...ESPECIALLY WED MORNING. NEAR SFC WINDS PER
BUFKIT SOUNDINGS LOOK A BIT TOO BREEZY WITHIN IN A COUPLE HUNDRED
FEET OF THE SFC FOR WIDESPREAD VALLEY FOG TUE MORNING...BUT WED
MORNING IS ANOTHER STORY. NAM SUGGESTING DEEP LIGHT WIND LAYER
UPWARDS OF 4 KFT...COUPLED WITH LIGHT WINDS AND CLEAR SKIES/GOOD
RADIATIONAL COOLING CONDITIONS. BARRING ANY CLOUDS MOVING IN FROM A
SHORTWAVE TO THE WEST LATE TUE NIGHT...OR A CHANGE IN THE WIND
FIELD...COULD BE A FOGGY WED MORNING FOR MANY WHO LIVE IN/AROUND THE
LOCAL RIVER VALLEYS.

WEDNESDAY PRESENTS SOME MORE CHALLENGES WITH A ROBUST AND WET GFS
SOLUTION AGAINST THE DRIER...LESS AMBITIOUS NAM/GEM/ECMWF. ALL
MODELS HAVE A PIECE OF ENERGY IN THE NORTHERN/SOUTHERN PORTIONS OF
THE UPPER LEVEL FLOW. MOST KEEP THEM SEPARATE...TAKING ONE ACROSS
THE MID MISSISSIPPI RIVER VALLEY TO OH RIVER VALLEY...AND THE OTHER
OVER FAR NORTHERN PARTS OF THE LOCAL REGION...AWAY FROM THE FORECAST
AREA. THE GFS WANTS TO - MORE OR LESS - PHASE THESE TWO TOGETHER
WHILE ALSO SHOWING A STRONGER SHORTWAVE IN THE NORTH. WED WOULD BE A
WET DAY IF THE GFS PROVES CORRECT. THE OTHERS WOULD KEEP CHANCES
SOUTH AND NORTHWEST. WITH THE GFS PRESENTING ITSELF AS AN OUTLIER
FOR THE MOMENT...WILL KEEP WED FORECAST DRY.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 220 PM CDT MON AUG 3 2015

MODELS TRENDING TOWARD A ZONAL TO SLIGHTED RIDGED UPPER LEVEL
PATTERN FOR THE END OF THE WEEK...SUGGESTIVE OF TEMPERATURES CLOSER
TO NORMAL. PERHAPS NOT AS COOL OF A WEEK AS IT MAY HAVE LOOKED A DAY
OR TWO AGO.

VARIOUS SHORTWAVES ARE PROGGED TO TRACK TOWARD THE REGION...BUT
WHERE/WHEN IS WHERE THE MODELS ARE STRUGGLING TO FIND SOME
CONSENSUS. THU NIGHT/FRI IS ONE PERIOD WHERE THERE DOES SEEM TO BE
SOME AGREEMENT FOR NOW...WITH THE GEM/GFS/ECMWF ALL BRINGING A
RIPPLE IN THE UPPER LEVEL FLOW ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY. THE GFS IS A TAD FASTER...BUT ALL SUGGEST THERE WOULD BE A
DECENT SHOT FOR SHOWERS/STORMS.

OVERALL...POSITIONING AND TIMING OF THE VARIOUS SHORTWAVES IS
UNCERTAIN THROUGH THE END OF THE WEEKEND...LOWERING CONFIDENCE FOR
PCPN CHANCES - ASIDE FROM THE THU NIGHT/FRI TIME FRAME. WILL LIKELY
HAVE TO SETTLE FOR A MODEL BLEND FOR CHANCES FOR NOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON AUG 3 2015

VFR WEATHER TO CONTINUE THROUGH TUESDAY EVENING. HIGH PRESSURE
WILL DRIFT OVER THE AREA AND OTHER THAN SOME PASSING SCATTERED
CLOUDS TONIGHT...SKIES EXPECTED TO BE CLEAR THROUGH THE PERIOD.
LIGHT WINDS TONIGHT WILL BECOME NORTHWEST AROUND 10 KNOTS TUESDAY
MORNING AND THEN EITHER GO SOUTHWEST OR LIGHT TUESDAY EVENING.

&&

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

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04


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