Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 231745
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1145 AM CST FRI JAN 23 2015

.UPDATE...
ISSUED AT 1145 AM CST FRI JAN 23 2015

DESPITE A WIDE SWATH OF WEAK ECHOES ON RADAR...VERY LITTLE IS REACHING
THE GROUND GIVEN VERY DRY NEAR SURFACE LAYER AND CLOUD BASES GENERALLY
5000 FT AGL OR HIGHER. A FEW FLURRIES HAVE BEEN REPORTED ACROSS
NORTHERN WI IN COLDER AIR MASS. FARTHER SOUTH ACROSS THE FORECAST
AREA...COULD STILL SEE SOME LIGHT DRIZZLE/RAIN THIS AFTERNOON...BUT
RISING AIR/GROUND TEMPERATURES TO ABOVE 32 DEGREES WILL LIMIT
FREEZING POTENTIAL. ALL SAID...WILL ALLOW WINTER WEATHER ADVISORY
TO EXPIRE AT NOON.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015

THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.

CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.

THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.

OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015

THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.

BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1145 AM CST FRI JAN 23 2015

VFR CONDITIONS EXPECTED AT BOTH TAF AIRFIELDS THROUGH THE
AFTERNOON. MAY EVEN SEE A FEW HOURS OF FULL SUN LATE AFTERNOON/
EARLY EVENING AS BACK EDGE OF MID-CLOUD DECK ACROSS CENTRAL MN IS
EXPECTED TO MOVE THROUGH UPPER MS RIVER VALLEY BEFORE THE NEXT
BATCH OF LOW STRATUS DROPS SOUTH FROM NORTHERN MN. DELAYED ONSET
OF THESE LOWER CEILINGS UNTIL 24.01Z AT KSRT AND 24.02Z AT KLSE.
THEREAFTER...MVFR/IFR CEILINGS WILL BE THE RULE THROUGH THE REST
OF THE TAF PERIOD. SOUTHWEST WIND WILL GRADUALLY DECREASE AND
SHIFT TO THE NORTHWEST BY THIS EVENING AND INTO THE OVERNIGHT.
LOOKING AHEAD...IFR CHANCES AND LIGHT SNOW INCREASE AT KRST/KLSE
AFTER 25.00Z.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.

MN...NONE.
IA...NONE.
&&

$$

UPDATE...ROGERS
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ROGERS


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