Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 231149
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
649 AM CDT SUN AUG 23 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN AUG 23 2015

MOST OF THE FORECAST SHIFT WAS SPENT TRYING TO BUILD IN DETAILS ON
THE TRENDS IN THE WEATHER FROM THE STRONG CYCLONE OVER THE
NORTHERN PART OF THE REGION. OVERALL...DIDNT GET THE STRENGTH OF
STORMS OUT OF THE SYSTEM...AND MARGINAL WIND SHEAR AT BEST AND
THIN INSTABILITY TONGUE HAD MUCH TO DO WITH THAT.

GOES WATER VAPOR SHOWING THE VIGOROUS SHORTWAVE TROUGH EJECTING
E-NE TOWARD KDLH AT 07Z WITH DEFORMATION PRECIPITATION SEEN ACROSS
ND IN REGIONAL RADARS. LOCALLY...THE COLD FRONT IS PUSHING TOWARD
ERN WI WITH LIGHT SHRA AHEAD OF THE FRONT AND SOME POST-FRONTAL
SHRA ABOUT A COUNTY FURTHER WEST. MULTIPLE FRONTOGENETIC BANDS
INDICATED IN THE RAP IN THE LOWER LEVELS. THESE WILL CONTINUE EAST
AND OUT OF THE FORECAST AREA DURING THE EARLY MORNING HOURS.

CLOUDS AND LOW-LEVEL SECONDARY TROUGH/FRONTAL AXIS ALONG
MN/DAKOTAS BORDER IS SHIFTING TOWARD THE AREA AS WELL. AS THE
SURFACE LOW SHIFTS EAST THROUGH SOUTHERN MANITOBA TODAY AND
FILLS...MANY OF THE FORCING FEATURES WEAKEN...INCLUDING THE
MN TROUGH AXIS AND CONVERGENCE ALONG IT. THE SYSTEM BECOMES A
BROAD CYCLONIC FLOW SCENARIO WITH ONLY A WEAK REMNANT TROUGH
AFFECTING NRN WI LATER THIS MORNING AND AFTERNOON. HAVE BROUGHT
SOME ISO-SCT SHRA BACK IN ALONG AND NORTH OF I-94 FOR MAINLY THE
17-22Z WINDOW. THERE IS SOME SUGGESTION IN THE HI-RES MODELS THAT
THIS COULD ALSO AFFECT CENTRAL WI. HAVE ALSO CONTINUED AFTERNOON
WIND GUSTS OF 25-35 MPH...REMAINING BELOW WIND ADVISORY CRITERIA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN AUG 23 2015

CONFIDENCE IS ABOVE AVERAGE THROUGH THURSDAY WITH QUIET WEATHER
EXPECTED AND BELOW NORMAL TEMPERATURES. ALONG AND NORTH OF I-94
TEMPERATURES WILL BE MUCH BELOW NORMAL. MONDAY WILL BE THE
COLDEST DAY BEFORE MODERATION SLOWLY OCCURS...ESPECIALLY WEDNESDAY
ON. HAVE LOWERED THE TEMPERATURES IN THE NORTH DOWN A NOTCH INTO
THE UPPER 50S FOR HIGHS MONDAY AS THE COLD AIR POCKET SLIPS
THROUGH UNDER THICK CLOUDS.

ON MONDAY..MAY HAVE TO TREND TOWARD HIGHER SHRA CHANCES NORTHEAST OF
I-94 MONDAY AFTERNOON DEPENDING ON THE TRACK OF WELL AGREED UPON
SHORTWAVE TROUGH ENERGY. THIS WAVE IS ACTUALLY THE CURRENT MN
VORTEX ROTATING AROUND THE LONGER WAVE TROUGH AND BACK IN FROM THE
NORTH MONDAY. CURRENTLY THE TRACK APPEARS TO FAVOR NORTHEASTERN WI
FOR SHRA...BUT WILL KEEP WATCH AS DIURNAL TIMING IS IDEAL FOR
ENHANCED SHRA COVERAGE. MONDAY AGAIN WILL SEE GUSTY NORTHWEST
WINDS OF 25-30 MPH IN THE AFTERNOON.

RIDGE BUILDING THEN BEGINS AND DOMINATES THROUGH THURSDAY.

SOME DIFFERENCES SHOW UP FRIDAY AND INTO SATURDAY. SOME RETURN
FLOW WARMING OCCURS AND THE GFS IS MORE AGGRESSIVE WITH RIDGE
BUILDING OVER THE NORTHERN CONUS. THE 23.00Z CANADIAN/ECMWF AND
21.18Z DGEX SOLUTIONS ARE AT ODDS WITH THE 23.00Z GFS...AS THEY
ALL HAVE A CUTOFF LOW DRIFTING E/SE THROUGH NEB/IA LATE IN THE
WEEK. HOWEVER...THE 23.00Z GEFS DOES HAVE SOME MEMBERS THAT PICK
UP ON THE LOW AS WELL...SO IT LOOKS LIKE THAT MAY BE A BETTER
SOLUTION FOR LATE WEEK. THIS WOULD BRING SOME RAIN CHANCES
POSSIBLY CLOSE OR INTO THE AREA. WILL HAVE TO LET THIS ALL SHAKE
OUT...AND WENT WITH CONSENSUS BLEND WHICH TURNS INTO SLIGHT

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 648 AM CDT SUN AUG 23 2015

AN UPPER LEVEL WILL MOVE NORTHEAST ACROSS NORTHERN MINNESOTA AND
WESTERN ONTARIO THROUGH TONIGHT. THIS LOW WILL PRODUCE A BROKEN
DECK OF MVFR CLOUDS THROUGH EARLY AFTERNOON...AND A 3 TO 5K DECK
OF CLOUDS FROM MID AFTERNOON INTO THE EVENING AT THE TAF SITES.

A TIGHT PRESSURE GRADIENT WILL PRODUCE SUSTAINED WEST WINDS OF
15 TO 25 KNOTS...AND WIND GUSTS IN THE 25 TO 35 KNOT RANGE.

&&

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

$$

SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE


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