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000
FXUS63 KARX 022333
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
533 PM CST SUN MAR 2 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 222 PM CST SUN MAR 2 2014

THE MAIN CONCERNS ARE WITH THE WIND CHILLS TONIGHT/MONDAY MORNING
AND THEN THE SNOW CHANCES MONDAY NIGHT.

THE MAIN ISSUE WITH THE WIND CHILLS FOR TONIGHT IS WHETHER THE
WINDS WILL REMAIN UP ENOUGH TO PRODUCE THEM. THE AREA OF HIGH
PRESSURE CURRENTLY CENTERED OVER SOUTH DAKOTA WILL DRIFT TO THE
EAST AND BECOME CENTERED OVER SOUTHERN MINNESOTA INTO NORTHERN
IOWA BY 12Z MONDAY. WITH THE WEAKENING GRADIENT...THE WIND SPEEDS
WILL BE DROPPING TO 5 MPH OR LESS AND WILL LIKELY BECOME CALM IN
SOME AREAS. THIS WILL ALSO ALLOW THE TEMPERATURES TO DROP OFF MORE
THAN PREVIOUSLY EXPECTED AND THESE WERE LOWERED SOME. WITH
TEMPERATURES IN THE TEENS AND 20 BELOW ZERO...ANY PUFF OF WIND
WILL CREATE WIND CHILLS IN THE ADVISORY RANGE. WILL HAVE ANOTHER
WIND CHILL ADVISORY FOR THE ENTIRE AREA THROUGH 15Z MONDAY.

THE NEXT CHANCE FOR SOME SNOW WILL COME MONDAY NIGHT INTO TUESDAY
MORNING. A SHORT WAVE TROUGH COMING OUT OF THE UPPER LEVEL LOW ON
THE BRITISH COLUMBIA COAST WILL DROP ACROSS THE GREAT LAKES
REGION. THE FORCING FROM THIS WAVE IS NOT EXPECTED TO BE ALL THAT
STRONG WITH WEAK PV ADVECTION IN THE 500-300 MB LAYER EXPECTED
ALONG WITH WEAK QG CONVERGENCE IN THE 1000-500 MB LAYER. THE
FRONTOGENESIS SHOULD ALSO BE WEAK AND LOOKS TO MAINLY BE CONFINED
TO THE 850-700 MB LAYER. BUFKIT SOUNDINGS FROM BOTH THE NAM AND
GFS SUGGEST THIS SYSTEM WILL HAVE A VERY DEEP DENDRITIC GROWTH
ZONE TO WORK WITH THE SOUNDING IN THE DGZ FROM THE SURFACE UP TO
AROUND 600 OR 550 MB. WITH THIS DEEP OF A DGZ...EXPECT THAT EVEN
THOUGH THE FORCING WILL NOT BE THAT STRONG...IT SHOULD BE ENOUGH
TO PRODUCE SOME LIGHT SNOW AND RAISED THE SNOW CHANCES UP TO 70
PERCENT ACROSS THE NORTHERN SECTIONS OF THE AREA. THIS SYSTEM
LOOKS TO BE MOVING BY PRETTY QUICK SO ONLY A SMALL LINGERING
CHANCE TUESDAY MORNING. SNOW AMOUNTS CURRENTLY LOOK TO BE IN THE 1
TO 2 INCH RANGE.

SOME MODEL AGREEMENT IN ANOTHER SHORT WAVE TROUGH ZIPPING ACROSS
THE AREA TUESDAY NIGHT. THE NAM SUGGESTS THE SURFACE RIDGE WILL BE
STRONG ENOUGH OVER THE REGION TO SQUASH ANY PRECIPITATION WITH
THIS WAVE. HOWEVER...THE GFS...02.12Z ECMWF AND GEM ALL SHOW SOME
LIGHT PRECIPITATION WITH THIS WAVE. THE GFS DOES SUGGEST MODERATE
PV ADVECTION WITH THIS WAVE BUT LITTLE OR NO FRONTOGENESIS. KEPT
THE SNOW CHANCES IN THE CHANCE RANGE BUT DID RAISE THEM TO 40
PERCENT ALONG AND SOUTH OF INTERSTATE 94.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 222 PM CST SUN MAR 2 2014

DIFFERENCES IN MODELS DURING THIS PERIOD REVOLVING AROUND WHAT A
SYSTEM COMING ACROSS EASTERN CANADA DOES. THE GFS AND 02.12Z GEM
SUGGEST THIS SYSTEM WILL GET CUT OFF FROM THE MAIN FLOW AND DRIFT
SOUTHEAST INTO THE NORTHERN GREAT LAKES WHILE THE ECMWF DOES NOT
CUT IT OFF AND KEEPS IT PROGRESSIVE AHEAD OF ANOTHER SYSTEM ALL
THE MODELS SHOW MOVING ACROSS CENTRAL CANADA. AS A RESULT...THE
GFS AND GEM SHOW LIGHT PRECIPITATION OVER THE AREA THROUGH
THURSDAY NIGHT WHILE THE ECMWF HAS A HIGH OVER THE REGION AND IS
DRY. ALL THE MODELS THEN SHOW A FRONT COMING THROUGH FRIDAY AND
FRIDAY NIGHT WITH THE SECOND SYSTEM COMING ACROSS CANADA. WITH LOW
CONFIDENCE ON WHICH SOLUTION WILL END BEING CORRECT...HAVE
MAINTAINED THE LOW END SNOW CHANCES THROUGH MUCH OF THE PERIOD.
TEMPERATURES STILL EXPECTED TO BE WARMER THAN RECENT VALUES WITH
HIGHS OF 25 TO 35 STARTING THURSDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 533 PM CST SUN MAR 2 2014

VFR CONDITIONS ARE EXPECTED THROUGH TOMORROW AFTERNOON AS A RIDGE
OF HIGH PRESSURE TRACKS THROUGH THE REGION. WINDS WILL GO LIGHT
OVERNIGHT AS THE CORE OF THE HIGH MOVES IN. SOME HIGH LEVEL CLOUD
COVER IS POSSIBLE TONIGHT AND TOMORROW...BUT NOTHING THAT SHOULD
BE LESS THAN 8KFT.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR WIZ017-029-032>034-
     041>044-053>055-061.

MN...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR MNZ079-086>088-
     094>096.

IA...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR IAZ008>011-018-019-
     029-030.

&&

$$

SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH