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000
FXUS63 KARX 271123
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
523 AM CST FRI FEB 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST FRI FEB 27 2015

THE MAIN FOCUS THROUGH TONIGHT IS ON TEMPERATURES AND HOW LOW THEY
WILL GET TONIGHT.

BROAD RIDGING IS IN PLACE ACROSS MUCH OF THE CENTRAL US WITH THE
CORE OF IT CENTERED NEAR THE NEBRASKA/IOWA STATE LINE. 27.07Z RAP
ANALYSIS SHOWS THE POOL OF COLDEST 850MB AIR EXTENDING EAST FROM
THE CORE OF THE RIDGE TOWARD THE GREAT LAKES. DRY AIR WILL KEEP
SKIES CLEAR THROUGH THE PERIOD AND LEAD TO IDEAL RADIATIONAL
COOLING CONDITIONS TONIGHT AS THE CORE OF THE RIDGE MOVES
OVERHEAD. TEMPERATURES SHOULD PLUMMET UNDER THE LIGHT WINDS WITH
MUCH OF THE AREA GETTING DOWN AROUND 10 BELOW WITH THE BOG COUNTRY
IN CENTRAL WISCONSIN DROPPING TO 20 BELOW OR LOWER. WINDS SHOULD
MAINLY BE AT 5 TO 10 MPH OR LOWER BUT COULD STILL CAUSE SOME BRIEF
WIND CHILLS TO DROP DOWN INTO THE 20 TO 30 DEGREES BELOW ZERO
RANGE MEANING ANOTHER WIND CHILL ADVISORY MAY BE NEEDED.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 AM CST FRI FEB 27 2015

THE MAIN FOCUS IN THE EXTENDED FORECAST IS ON TWO SYSTEMS WHICH
COULD BRING ACCUMULATING SNOW TO THE REGION.

THE FIRST SYSTEM CONTINUES TO TREND FURTHER SOUTH WITH THE MAIN
SNOW BAND THIS WEEKEND. BROAD LOW LEVEL WARM AIR ADVECTION AND
MOISTURE RETURN WILL PUSH UP FROM THE SOUTHERN PLAINS SATURDAY
INTO SUNDAY AS SOUTHWESTERLY FLOW ALOFT SETS UP ACROSS THE CONUS.
MUCH OF THE FOCUS APPEARS TO COME ALONG THE LOW LEVEL BOUNDARY
WHICH DOES NOT GET MUCH OF A KICK TO THE NORTH DUE TO THE FACT
THAT WE ARE IN THIS BROAD FLOW WITH THERE NOT BEING AN AMPLIFIED
SYSTEM COMING THROUGH. THE 27.00Z NAM/ECMWF ARE ALMOST COMPLETELY
DRY FOR SATURDAY NIGHT INTO SUNDAY WHILE THE 27.00Z GFS IS THE
HEAVIEST ON QPF WITH THERMAL PROFILES SHOWING SOME DEEPER MOISTURE
POOLING ALONG THE SURFACE COLD FRONT. HAVE LEFT SOME CHANCES FOR
SNOW IN THE FORECAST...BUT CONTINUE THE TREND OF HAVING LESS SNOW
ACCUMULATIONS IN THE FORECAST WITH LESS THAN AN INCH EXPECTED IN
SOUTHEAST MINNESOTA TO NORTH CENTRAL WISCONSIN AND 1-2 INCHES
FORECAST FOR NORTHEAST IOWA INTO SOUTHWEST WISCONSIN.

THE BIGGER DEAL APPEARS TO BE ON MONDAY NIGHT INTO TUESDAY NIGHT
AS PART OF THE 4 CORNERS TROUGH SPLITS OFF AND PROPAGATES
NORTHEAST THROUGH THE SOUTHWESTERLY FLOW ALOFT. THIS SHORT WAVE
TROUGH LEADS TO A DEEPER SURFACE/LOW LEVEL CIRCULATION WHICH WILL
BE AIDED BE A DEEPENING OF THE LARGER WAVE TROUGH THAT FORMS FROM
SOUTHERN CANADA INTO THE SOUTHWESTERN US. FAIRLY CONSISTENT SIGNAL
FROM THE 27.00Z GFS/ECMWF/GEM WITH BRINGING THE 850MB LOW THROUGH
IOWA WITH THE WARM LAYER NOSING UP INTO SOUTHERN WISCONSIN. THIS
COULD LEAD TO SOME PRECIPITATION TYPE ISSUES WITH THE WARM LAYER
ON THE GFS GOING UP TO AROUND +1 OR +2 MEANING THE MAIN
CHANGEOVER WOULD LIKELY BE TO SLEET/SNOW PELLETS.
HOWEVER...THERMAL PROFILES THROUGH THE REST OF THE REGION LOOKS
LIKE IT SHOULD BE COLD ENOUGH TO STAY ALL SNOW. THE GFS IS DEEPER
WITH THE SURFACE LOW COMPARED TO THE ECMWF THOUGH BOTH BRING UP TO
A HALF INCH OF QPF THROUGH WITH SNOW RATIOS LIKELY ON THE LOWER
SIDE DUE TO THE WARMER AIR MOVING IN. A LOT CAN CHANGE BUT THIS
SYSTEM WILL NEED TO BE WATCHED OVER THE NEXT FEW DAYS FOR TRENDS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 523 AM CST FRI FEB 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN IN CONTROL INTO SATURDAY MORNING. THE NEXT
SYSTEM APPROACHES THE REGION SATURDAY AFTERNOON INTO SATURDAY
NIGHT AND MAY BRING SOME LIGHT SNOW TO AREAS MAINLY SOUTH OF THE
INTERSTATE 90 CORRIDOR.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ008>010-
     018-019-029-030.

&&

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...WETENKAMP