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000
FXUS63 KARX 091140
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
640 AM CDT SUN MAR 9 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM CDT SUN MAR 9 2014

HIGH PRESSURE CENTERED OVER NORTHERN MISSOURI THIS MORNING WILL
CONTINUE TO SINK SOUTHEAST REACHING THE OHIO RIVER VALLEY TODAY.
WARM AIR ADVECTION ON THE BACK SIDE OF THE HIGH WILL BRING WARMER
AIR OVER THE REGION AND THE QUESTION BECOMES HOW WARM WILL
TEMPERATURES GET OVER THE NEXT COUPLE OF DAYS GIVEN THE 10 TO 25
INCHES OF SNOW CURRENTLY SITTING ON THE GROUND. THE 09.00Z GFS
SUGGEST 925 MB TEMPERATURES FOR LATE THIS AFTERNOON SHOULD RANGE
FROM ABOUT 0C ACROSS THE NORTH TO 7C IN THE SOUTH. THE WARMEST AIR
SHOULD BE OVER THE AREA TONIGHT WHEN 10C AIR AT 925 MB GETS INTO
THE SOUTHERN AREAS BEFORE COOLING TAKES OVER MONDAY WITH VALUES
RETURNING TO SIMILAR LEVELS THAT ARE EXPECTED FOR TODAY. THE
BUFKIT SOUNDINGS FROM THE GFS SHOW VERY LIMITED MIXING TO OCCUR
OVER THE NEXT TWO DAYS...WITH THE TOP OF THE MIXED LAYER POSSIBLY
REACHING INTO THIS WARMER AIR AT 925 MB. THE OTHER COMPLICATING
FACTOR IS THE SNOW PACK AND A LOOK BACK AT PAST EVENTS SHOWS KRST
HAS NEVER TOPPED 45 DEGREES WITH 20 INCHES OF SNOW ON THE GROUND
WHILE KLSE HAS HIT 50 DEGREES ONLY ABOUT 5 TIMES WITH ANY AMOUNT
OF SNOW PACK. WHILE THE SUN ANGLE CONTINUES TO INCREASE...JUST DO
NOT FEEL THERE WILL BE ENOUGH ENERGY FROM THE SUN TO OVERCOME THE
SNOW PACK AND WITH WEAK COLD AIR ADVECTION OCCURRING
MONDAY...DROPPED THE TEMPERATURES BACK JUST A LITTLE BIT FROM THE
PREVIOUS FORECAST.

THE NEXT CHANCE FOR SOME PRECIPITATION WILL START MONDAY NIGHT AND
CONTINUE THROUGH TUESDAY. ENERGY COMING IN OFF THE PACIFIC TONIGHT
WILL SEND A SHORT WAVE TROUGH FROM THE HIGH PLAINS TOWARD THE OHIO
RIVER VALLEY. AT THE SAME TIME...ANOTHER SHORT WAVE TROUGH WILL BE
APPROACHING FROM THE NORTH IN THE NORTHERN STREAM. MOST OF THE
FORCING FROM THE PACIFIC SHORT WAVE TROUGH WILL MISS THE AREA TO
THE SOUTH...WHILE THE NORTHERN STREAM SHORT WAVE TROUGH SHOULD
PRODUCE MODERATE TO STRONG PV ADVECTION IN THE 500-300 MB
LAYER. MODERATE QG CONVERGENCE IN THE 1000-700 MB LAYER SHOULD
OCCUR WITH THESE WAVES MONDAY NIGHT AND TUESDAY MORNING OVER THE
SOUTHERN HALF OF THE AREA WITH WEAK CONVERGENCE IN THE UPPER
LEVELS. THE STRONGEST FRONTOGENESIS LOOKS TO BE IN THE 850-700 MB
LAYER...BUT LOOKS TO SET UP MORE ACROSS CENTRAL INTO SOUTHERN IOWA
WITH SOME WEAK FRONTOGENESIS IN THE 700-500 MB LAYER. EXPECT THAT
THERE WILL BE ENOUGH FORCING TO PRODUCE A BAND OF PRECIPITATION
ACROSS MAINLY THE SOUTHERN SECTIONS OF THE AREA AND RAISED THE
CHANCES UP TO 70 PERCENT FOR NORTHEAST IOWA INTO SOUTHWEST
WISCONSIN. SOME CONCERN WITH PRECIPITATION TYPES AT THE ONSET.
LOOK LIKE ICE SHOULD BE PRESENT IN THE CLOUDS BUT WITH A WARM
LAYER ALOFT BETWEEN 900 AND 850 MB. THIS WILL LIKELY PRODUCE SOME
PARTIAL MELTING WITH THE POSSIBILITY OF SOME SLEET OCCURRING.
OTHERWISE...LOOKS LIKE A RAIN/SNOW MIX POSSIBLE BASED ON SURFACE
TEMPERATURES.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM CDT SUN MAR 9 2014

THE LINGERING PRECIPITATION FROM TUESDAY SHOULD EXIT THE REGION
DURING THE EVENING AND REMOVED THE PRECIPITATION CHANCES FOR THE
OVERNIGHT HOURS. NORTHWEST FLOW ALOFT WILL SET UP BEHIND THE
DEPARTING SYSTEM WITH THE MODELS ALL SHOWING A SHORT WAVE TROUGH
IN THIS FLOW FOR THURSDAY NIGHT AND FRIDAY. DIFFERENCES THOUGH
BETWEEN THE MODELS ON HOW FAR SOUTH THIS WAVE WILL BE ALONG WITH
THE ASSOCIATED SURFACE LOW. THE 09.00Z ECMWF IS THE FARTHEST SOUTH
AND CURRENTLY THE ONLY MODEL SUGGESTING ANY PRECIPITATION IN THIS
TIME FRAME WITH THE GFS AND 09.00Z GEM KEEPING THE PRECIPITATION
OFF TO THE NORTHEAST ACROSS THE GREAT LAKES. UNTIL MORE OF A MODEL
CONSENSUS DEVELOPS...WILL KEEP THE FORECAST DRY WITH TEMPERATURES
AGAIN MODERATING INTO THE 40S FOR THE END OF THE PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CDT SUN MAR 9 2014

MID AND HIGH CLOUDS /MAINLY ABOVE 15K FEET/ MOVED INTO THE AREA
OVERNIGHT. THESE CLOUDS ARE ASSOCIATED WITH A SHORT WAVE MOVING
THROUGH SOUTHERN MANITOBA. THESE CLOUDS WILL GRADUALLY LOWER TO
AROUND 10K FEET THIS EVENING...AND THEN SKIES WILL CLEAR AS
SUBSIDENCE MOVES INTO THE AREA OVERNIGHT.

BOTH THE RAP AND NAM INDICATE THAT THERE WILL BE A POSSIBILITY OF
LOW LEVEL WIND SHEAR DEVELOPING AT KRST BY 09.17Z. THIS IS DUE TO
THE LOW LEVEL INVERSION REMAINING INTACT AND NOT ALLOWING THE
WINDS TO BECOME GUSTY. MEANWHILE THE GFS DOES DEVELOP SOME GUSTS
INTO THE 25 TO 30 KNOT RANGE. SINCE THE NAM AND RAP USUALLY HAVE
PROBLEMS WITH NOT ERODING THE LOW LEVEL INVERSIONS IN THIS SYNOPTIC
PATTERN OPTED TO GO MORE TOWARDS THE GFS.

&&

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

$$

SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE