Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 171814
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1214 PM CST WED DEC 17 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 116 AM CST WED DEC 17 2014

PERIODS OF LOW CLOUDS AND FLURRIES ANTICIPATED TODAY IN CYCLONIC
FLOW AROUND THE LARGE LONG WAVE TROUGH AND EMBEDDED CLOSED
CIRCULATION OVER THE REGION. FOG ENHANCEMENT SATELLITE IMAGERY
SHOWS THE BACK EDGE TO THE LOW CLOUDS FROM CENTRAL MN DOWN TO
SOUTH CENTRAL MN. HOWEVER...MORE CLOUDS ARE DROPPING SOUTH WITH
THE NEXT WAVE IN THE FLOW. ANTICIPATING MAINLY CLOUDY CONDITIONS
ALONG WITH SOME FLURRIES FOR AREAS ALONG AND NORTH OF I-94. BEST
CHANCE TO SEE ANY PROLONGED PEEKS AT THE SUN WILL BE OVER NORTHERN
IOWA AND SOUTHERN MN.

COLDEST POOL OF AIR OVER THE AREA TODAY...WITH SOME MODERATION
EXPECTED FOR LATER IN THE WEEK AS THE TROUGH MOVES AWAY.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 116 AM CST WED DEC 17 2014

BLOCKY UPPER LEVEL PATTERN LOOKS TO CONTINUE THROUGH THE REMAINDER
OF THE WEEK. CURRENT SHORT WAVE QUICKLY SHEARS OUT AND MOVES EAST
WITH RIDING RUNNING FROM THE CENTRAL CONUS UP INTO CENTRAL CANADA.
OMEGA BLOCK LINGERS ALL THE WAY TO THE WEEKEND BEFORE IT SHIFTS
EAST FAR ENOUGH FOR TROUGHING TO START WORKING ITS WAY INTO THE
REGION. APPEARS A PATTERN SHIFT WILL THEN TAKE PLACE WITH A MORE
ZONAL REGIME BRINGING SEVERAL WEAKER SHORT WAVE TROUGHS EASTWARD
ALONG THE CANADIAN BORDER. MODELS STRUGGLING A BIT WITH THIS
PATTERN SHIFT...BUT ALL SUGGEST THE POTENTIAL FOR SOME
PRECIPITATION FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
TEMPERATURES WILL BE NEAR SEASONAL NORMALS...AND HOVERING CLOSE
ENOUGH TO THE FREEZING MARK DIURNALLY SO THAT A MENTION OF
RAIN/SNOW WILL BE NEEDED DURING THE DAYLIGHT HOURS. CONFIDENCE IN
TIMING AND PRECIPITATION CHANCES IS BELOW AVERAGE THROUGH THIS
PERIOD WITH THE PATTERN CHANGE STILL EVOLVING. STILL A CHANCE
THAT THESE DISTURBANCES COULD BRING A WHITE CHRISTMAS TO THE
REGION...SO SNOW LOVERS SHOULD NOT GIVE UP HOPE JUST YET.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1215 PM CST WED DEC 17 2014

CHALLENGING FORECAST PERIOD FOR THE TAF SITES OF KLSE AND KRST.
CURRENTLY THE REGION IS UNDER A SHARP AND DEEP TEMPERATURE
INVERSION WHICH IS ACTING TO LIMIT MIXING AND CONTAIN MOISTURE IN
THE LOW-LEVELS /HZ OR BR/. WHILE SOME CLEARING HAS WORKED THROUGH
KRST AND IS INVOF KLSE...CLEARING IS LEADING TO MORE CUMULUS
DEVELOPMENT WITH ENOUGH VERTICAL CLOUD DEPTH TO PRODUCE MVFR
-SHSN. SO...PERIODS OF SCT-BKN CIGS SHOULD BE AROUND THROUGH THE
AFTERNOON. KRST MAY BE RIGHT ON THE IFR/MVFR BOUNDARY NEAR 1KFT
/BKN008-BKN012/.

ONCE THE SUN BEGINS TO SET...THE CUMULUS SHOULD DISSIPATE AND A
PERIOD OF CLEAR SKIES SEEMS PROBABLE AT KRST...POSSIBLE AT KLSE.
HOWEVER...OVERNIGHT WINDS ABOVE THE SURFACE ARE EXPECTED TO BE MORE
FROM THE NORTHEAST AND SURGE MORE CLOUD INTO THE TAF SITES. UNTIL
THAT TIME...THERE IS A CHANCE KRST COULD GET INTO IFR FOG SHOULD
SKIES REMAIN CLEAR LONG ENOUGH. HAVE NOT ADDRESSED THAT IN THE TAF
AS OF YET BUT DID KEEP MVFR FOG.

OVERALL...HAVE KEPT KLSE IN THE CLOUDS ALTHOUGH THERE MAY BE SOME
CLEARING PERIODS UNTIL LATER TONIGHT. HAVE A BIT MORE OPTIMISM FOR
THE KRST TAF.

&&

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

$$

SHORT TERM...MW
LONG TERM...MW
AVIATION...DB



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