Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 150530
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1130 PM CST SUN DEC 14 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 236 PM CST SUN DEC 14 2014

THE MAIN FOCUS THROUGH TOMORROW CONTINUES TO BE ON THE DENSE FOG
AND RAIN POTENTIAL INTO TOMORROW.

AS HAS BEEN THE CASE THE PAST FEW DAYS...SIGNIFICANT MOISTURE
REMAINS TRAPPED UNDER A SHALLOW AND STRONG INVERSION DUE TO WARM
AIR AROUND 925MB. NOT MUCH IS EXPECTED TO CHANGE OVERNIGHT AS A
TROUGH IN THE SOUTHERN PLAINS PROPAGATES NORTHEAST INTO THE MID
MISSISSIPPI VALLEY REGION. DENSE FOG HAS BEEN REPORTED THROUGHOUT
THE DAY AND EXPECT IT TO JUST GET WORSE OVERNIGHT.

STILL SOME PATCHY DRIZZLE EXPECTED TONIGHT WITH THE WEAK LIFT IN
THE BOUNDARY LAYER WITH THE DEEPER FORCING COMING IN TOMORROW
MORNING AS A LEAD SHORTWAVE TROUGH RUNS AHEAD OF THE MAIN CLOSED
LOW. FAIRLY GOOD TIMING SHOWING UP BETWEEN THE 14.12Z MODELS WITH
HAVING THIS BAND MOVING INTO NORTHEAST IOWA AROUND DAYBREAK AND
LIFTING TO THE NORTH THROUGH THE MORNING AND AFTERNOON. AFTER THAT
FEATURE MOVES THROUGH...IT LOOKS LIKE MORE WIDESPREAD DRIZZLE WILL
DEVELOP AHEAD OF THE SURFACE LOW/TROUGH AND PERSIST THROUGH THE
REST OF THE AFTERNOON. WHILE FOG VISIBILITY MAY BRIEFLY IMPROVE
WITH THE RAIN COMING IN...IT IS EXPECTED TO DROP BACK DOWN AND
POSSIBLY BECOME DENSE AGAIN ON INTO THE EVENING. CURRENT DENSE FOG
ADVISORY COULD BE EXTENDED BUT WILL HAVE TO EVALUATE HOW THE RAIN
AFFECTS CONDITIONS.

OTHERWISE...TEMPERATURES SHOULD NOT BUDGE MUCH OVERNIGHT...SO
ESSENTIALLY TOOK THE HIGH TEMPERATURE FORECAST FOR TODAY AND JUST
SHAVED A FEW DEGREES OFF OF IT FOR THE LOW TEMPERATURES TONIGHT.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 236 PM CST SUN DEC 14 2014

COLDER AIR WILL BE WRAPPING INTO THE REGION ON THE BACK SIDE OF
THE SYSTEM EARLY ON TUESDAY AND WILL CAUSE THE RAIN TO CHANGE OVER
TO SNOW. SNOW ACCUMULATIONS WILL BE MINOR WITH THE HIGHEST TOTALS
OF AN INCH OR LESS EXPECTED IN SOUTHEAST MINNESOTA. A BRIEF
DUSTING WILL BE POSSIBLE FOR THE REST OF THE REGION THOUGH IT
APPEARS THAT THE MAIN PRECIPITATION AXIS LIFTS NORTHWARD BEFORE
THE COLDER AIR CAN GET IN.

AS COLDER AIR MOVES IN BEHIND THE SYSTEM...THE QUESTION WILL BE
WITH HOW LONG CLOUD COVER HOLDS ON AND ALSO WHETHER THERE WILL BE
ANY FLURRIES. WENT A BIT PESSIMISTIC ON CLOUD COVER GOING INTO
TUESDAY NIGHT BUT DID NOT INTRODUCE ANY FLURRIES AT THIS POINT.

BEYOND THIS...HIGH PRESSURE WILL SIT ACROSS THE REGION THROUGH THE
REST OF THE WEEK AND KEEP TEMPERATURES AROUND NORMAL. THE 14.12Z
GFS/ECMWF HAVE DIFFERING OPINIONS ON A SYSTEM THAT WILL TRACK TO
THE SOUTHEAST OF THE REGION ON SATURDAY WITH THE GFS BEING MORE
NORTHWEST WITH ITS TRACK THOUGH MOST OF THE PRECIP STAYS MORE INTO
EASTERN IOWA/NORTHERN ILLINOIS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1130 PM CST SUN DEC 14 2014

IFR/LIFR CONDITIONS IN MIST/FOG TO PERSIST AT KRST/KLSE THROUGH
MONDAY MORNING. ALTHOUGH CEILINGS LIKELY TO REMAIN BELOW 1000 FT
AGL THROUGH 16.06Z...VISIBILITY EXPECTED TO IMPROVE AROUND 15.17Z
AND THEREAFTER AS AN AREA OF RAIN LIFTS NORTHEASTWARD ACROSS THE
REGION. PERIODS OF LIGHT RAIN WILL CONTINUE THROUGH MONDAY
AFTERNOON/EVENING WITH VISIBILITY GENERALLY IN THE 1 TO 3SM
RANGE. LIGHT SOUTHERLY WINDS WILL GRADUALLY SHIFT TO THE SOUTHEAST
AND THEN THE NORTHEAST BY MONDAY AFTERNOON. TIMING NOT EXACT...BUT
DID INTRODUCE NORTHERLY WINDS AT KRST BY 16.01Z AND KLSE BY 16.04Z
AS A SURFACE COLD FRONT SWEEPS ACROSS THE REGION.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR WIZ017-029-032>034-
     041>044-053>055-061.

MN...DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR MNZ079-086>088-
     094>096.

IA...DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR IAZ008>011-018-019-
     029-030.

&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ROGERS


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