Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 250931
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
331 AM CST SUN JAN 25 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST SUN JAN 25 2015

THE MAIN FOCUS IS ON THE DEPARTING SNOW THIS MORNING FOLLOWED BY
THE TEMPERATURE TRENDS TONIGHT.

CURRENTLY...AN OPEN MID LEVEL TROUGH IS PROPAGATING EAST ACROSS
IOWA WITH A SURFACE LOW ANALYZED NEAR DES MOINES. TRENDS CONTINUE
TO BE FOR THIS SYSTEM TO BE FURTHER SOUTH THAN PREVIOUSLY FORECAST
WHICH IS REDUCING THE SNOW AMOUNTS LOCALLY AND ALSO GOING TO MEAN
THAT THE PRECIPITATION SHOULD END SOONER AS WELL. THERE IS A
SMALL CHANCE THAT THE COLUMN LOSES ICE ALONG THE NORTHERN FRINGE
OF THE PRECIPITATION SHIELD BUT IT APPEARS THAT SUBSIDENT AND
DRIER AIR MOVES IN RATHER QUICKLY THROUGH THIS MORNING. STORM
TOTAL SNOW AMOUNTS LOOK TO BE RATHER MEAGER AT AN INCH OR LESS.

HIGH TEMPERATURES WILL BE MET FIRST THING THIS MORNING WITH COLDER
AIR MOVING DOWN FROM THE NORTHEAST THROUGHOUT THE DAY. A SURFACE RIDGE
OF HIGH PRESSURE WILL MOVE THROUGH THE REGION THIS EVENING WITH
RETURN SOUTHERLY LOW LEVEL FLOW KICKING IN OVERNIGHT. THIS SHOULD
LEAD TO A NON-DIURNAL TEMPERATURE TREND WITH LOW TEMPERATURES
OCCURRING IN THE EVENING.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 331 AM CST SUN JAN 25 2015

THE NEXT ROUND OF PRECIPITATION LOOKS LIKE IT WILL COME IN EARLY
ON MONDAY AS A WEAK MID LEVEL SHORTWAVE TROUGH DIVES DOWN INTO THE
WESTERN GREAT LAKES THROUGH THE NORTHWEST FLOW ALOFT. PRECIPITATION
TYPE APPEARS TO BE THE MAIN QUESTION...PARTICULARLY WITH WHETHER
THERE WILL BE ICE IN THE COLUMN OR NOT. 25.00Z NAM/GFS SOUNDINGS
ARE SHOWING SOME DEEPER MOISTURE/LIFT FURTHER NORTHEAST TOWARD
THE SURFACE LOW. AFTER A BRIEF PERIOD OF SNOW IN THE MORNING...IT
APPEARS THAT THE COLUMN LOSES ICE YET KEEPS SOME STRONG LOW LEVEL
FORCING/MOISTURE IN PLACE AS THE WARM FRONT MOVES IN. PERHAPS THE
BIGGEST QUESTION IS WITH WHETHER THE MODELS ARE OVERDOING THE
AMOUNT OF LOW LEVEL RH/LIFT OR IF IT IS LEGIT...PARTICULARLY
ALONG/NEAR THE FRONT. WITH SURFACE TEMPERATURES STARTING OFF BELOW
FREEZING...THERE IS SOME CONCERN THAT SOME ICING COULD
OCCUR...PARTICULARLY IN THE LATE MORNING TO AFTERNOON HOURS.

MID TO UPPER LEVEL RIDGING WILL THEN MOVE IN WITH WARMER AIR BEING
ADVECTED IN FROM THE SOUTHWEST ON WEDNESDAY. STILL SOME QUESTIONS
ABOUT HOW WARM IT WILL BE AS GUIDANCE HAS TAKEN A BIT OF A STEP
DOWN ON TEMPERATURES...POSSIBLY DUE TO HOW MUCH CLOUD COVER THERE
WILL BE. ANOTHER QUICK MOVING MID LEVEL SHORT WAVE TROUGH IS
EXPECTED TO DROP DOWN INTO THE WESTERN GREAT LAKES REGION ON
WEDNESDAY NIGHT INTO THURSDAY WITH SNOW EXPECTED TO BE THE MAIN
PRECIPITATION TYPE OF THIS EVENT. BEYOND THIS...AM EXPECTING A BIT
OF A COOLING TREND GOING INTO NEXT WEEKEND AS A COLD LOW LEVEL AIR
MASS DROPS DOWN FROM CANADA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM CST SAT JAN 24 2015

AN MVFR CEILING DEVELOPED EARLIER THIS EVENING IN A NARROW AREA
BETWEEN MSP AND RST...WHICH HAS STAYED GENERALLY IN PLACE.
MEANWHILE...MVFR CEILINGS ARE JUST LURKING OFF TO THE NORTHEAST OF
LSE. WITH A NORTHEAST FLOW DEVELOPING ASSOCIATED WITH LOW PRESSURE
TRACKING SOUTHEAST ACROSS IOWA...ANTICIPATING BOTH SITES TO BE IN
MVFR STRATUS BY 07Z. SNOW IS LIKELY TO DEVELOP AS WELL BETWEEN
07-09Z...ALLOWING THE CEILING AND VISIBILITY TO DROP TO IFR AT
RST. LSE SHOULD SEE VISIBILITIES DROP TO IFR AS WELL...BUT
ANTICIPATING CEILINGS TO STAY UP AT MVFR. SNOW LOOKS TO BEGIN
DIMINISHING AROUND 13Z...TOTALING UP TO LESS THAN 1 INCH. HOWEVER...A
LINGERING SURFACE TROUGH IN SOUTHEAST MN MAY ALLOW FOR A FEW HOURS
OF LIGHT FREEZING DRIZZLE TO PERSIST UNTIL 16Z. EXPECT WINDS TO
INCREASE TOO THIS MORNING UPWARDS OF 15 KT AT RST. DRIER AIR
COMING IN ON NORTHEAST WINDS LOOKS TO LIFT LSE TO VFR BY
18Z...WITH A SLOWER ARRIVAL TIME OF 00Z NOW AT RST BEING CLOSER TO
THAT OLD SURFACE TROUGH. VFR CONDITIONS WITH LIGHTER WINDS
ANTICIPATED FOR THE EVENING WITH HIGH PRESSURE MARCHING ACROSS THE
TAF SITES.


&&

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

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ


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