Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 070750
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
249 AM CDT TUE JUL 7 2015

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 249 AM CDT TUE JUL 7 2015

CANADIAN WILDFIRE SMOKE STILL PREVALENT ACROSS PORTIONS OF THE
AREA...DRAGGED IN WITH NORTHERLY SURFACE FLOW/SUBSIDENCE BEHIND
DEPARTING COLD FRONT. SURFACE OBSERVATIONS ALONG/SOUTH OF A MEDFORD
WI-LA CROSSE WI-CHARLES CITY IA STILL IN THE 1-3SM RANGE WITH ACRID
SMELL OF THIS SMOKE EVIDENT OUTSIDE THE NWS LA CROSS OFFICE AT
PRESENT. OTHERWISE...SKIES WERE SLOWLY CLEARING FROM NORTHWEST TO
SOUTHEAST BEHIND THE DEPARTING COLD FRONT WHILE TEMPERATURES AT 2 AM
HOVERED IN THE MIDDLE 50S ACROSS NORTHERN WI...TO THE UPPER
50S/LOWER 60S ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST WI.

PER EXTRAPOLATION OF IMPROVING VISIBILITIES UPSTREAM AND AIR QUALITY
FORECAST GUIDANCE...LOOKS LIKES WE WILL SEE/SMELL SMOKEY CONDITIONS
ACROSS PORTIONS OF SOUTHERN WI INTO NORTHEAST IA THROUGH THIS
MORNING BEFORE MIXING THROUGH THE BOUNDARY LAYER TAKES PLACE BY NOON
AND DISPERSES PARTICULATES...THEREBY SLOWLY IMPROVING CONDITIONS.
THE REST OF TODAY WILL SEE HAZY SUNSHINE AS THE SMOKE LIFTS INTO A
LAYER. OTHERWISE...LOOK FOR COOLER/DRIER CONDITIONS TODAY AS HIGH
PRESSURE BUILDS IN FROM THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER REGION. HIGHS TODAY ARE EXPECTED TO TOP OFF IN THE
UPPER 60S TO THE MIDDLE 70S WITH NORTH WINDS AROUND 10 MPH.

FOR TONIGHT...HIGH PRESSURE WILL SET UP OVERHEAD WITH COOL OVERNIGHT
LOWS RANGING FROM THE MIDDLE/UPPER 40S IN THE SAND COUNTRY OF
CENTRAL WI...TO THE LOWER 50S ELSEWHERE. HAVE INCLUDED PATCHY FOG IN
THE RIVER VALLEYS WITH AREAS OF FOG IN THE SAND COUNTRY OF CENTRAL
WI WITH THIS SETUP. WILL HAVE TO WATCH INCREASING CIRRUS VEIL THAT
MODELS ARE DEPICTING AHEAD OF A WEAK SHORTWAVE TROUGH IN THE CENTRAL
PLAINS. THIS MAY LIMIT RADIATIONAL COOLING/FOG POTENTIAL. HOWEVER...
IF THERE IS LESS CIRRUS...FOG COULD BECOME MORE WIDESPREAD. WILL
HAVE TO KEEP AN EYE ON THIS.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 249 AM CDT TUE JUL 7 2015

LOOKS LIKE DRY/COOLER THAN NORMAL CONDITIONS THROUGH THURSDAY AS
HIGH PRESSURE REMAINS IN CONTROL ACROSS THE REGION. PLAN ON HIGHS IN
THE MIDDLE/UPPER 70S.

SHOWER THUNDERSTORM CHANCES RETURN TO THE AREA AND LINGER THROUGH
THE WEEKEND AS A WARM FRONT LIFTS NORTHWARD INTO THROUGH THE REGION.
GFS PRODUCES 2000-3000J/KG OF MUCAPE ON SATURDAY/SUNDAY AFTERNOONS
AS PRECIPITABLE WATER VALUES INCREASE TO AROUND 2 INCHES. BULK SHEAR
LOOKS MINIMAL IN THE 15-20KT RANGE IN THE HIGHER CAPE AXIS...SO
MAINLY LOOKS LIKE THE POTENTIAL FOR EFFICIENT RAIN-MAKING
THUNDERSTORMS WITH PERHAPS SOME LOCALLY HEAVY RAINFALL. WILL HAVE TO
KEEP A CLOSER EYE ON THIS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1144 PM CDT MON JUL 6 2015

THE NORTHERN EDGE OF THE SMOKE IS APPROACHING BOTH TAFS SITES.
AS A RESULT...EXPECT THE MVFR VISIBILITY RESTRICTIONS TO IMPROVE
BETWEEN 07.06Z AND 07.10Z. AFTER THIS SMOKE MOVES OUT...
VISIBILITIES WILL BE VFR.

THE MVFR CEILING NORTHERN EDGE IS ALSO CLOSE TO THE TAF SITES AND
THIS CLEARING SHOULD MOVE INTO THEM BETWEEN 07.05Z AND 07.07Z.
ONCE THIS OCCURS...THE CEILINGS WILL BE MAINLY CLEAR. HOWEVER
THERE MAY STILL BE SOME SMOKE AROUND THE AREA ABOVE 15K FEET.

&&

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

$$

SHORT TERM...DAS
LONG TERM...DAS
AVIATION...BOYNE



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