National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KARX 120341
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1041 PM CDT TUE MAR 11 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 309 PM CDT TUE MAR 11 2014

THE MAIN FOCUS THROUGH TOMORROW IS WITH HOW FAST THE BAND OF
PRECIPITATION SHIFTS TO THE SOUTH TONIGHT FOLLOWED BY SNOW SHOWER
CHANCES TOMORROW MORNING ALONG WITH HOW COLD IT WILL BE.

SURFACE/LOW LEVEL TEMPERATURES PROVED TO BE A TAD TOO WARM TODAY
TO CAUSE MUCH IF ANY SNOW TO DEVELOP ALONG THE BAND OF
PRECIPITATION. 11.17Z RAP SOUNDINGS CONTINUE TO SHOW THAT THE LOW
LEVELS SHOULD STAY WARM ENOUGH INTO THIS EVENING TO MAINLY YIELD
RAIN WITH A BRIEF TRANSITION TO SNOW ON THE BACK/NORTH SIDE OF
THE BAND. THE 17.12Z HRRR/RAP SHOW THIS BAND GETTING SOUTH OF
DUBUQUE BY MID EVENING.

AS A DEEPENING SURFACE LOW TRACKS TO THE SOUTHEAST OF THE REGION
OVERNIGHT INTO TOMORROW MORNING...AN INVERTED SURFACE TROUGH WILL
ROTATE FROM EAST TO WEST ACROSS THE REGION AS A SHORT WAVE MID
LEVEL TROUGH DROPS DOWN FROM ONTARIO. WITH COLDER AIR MOVING IN
WITH THIS TROUGH A SATURATED LAYER SHOULD DEVELOP IN THE
ICE NUCLEATION ZONE BELOW -8C WITH JUST ENOUGH LIFT FROM THE
SURFACE TROUGH TO PRODUCE SOME SNOW SHOWERS. 11.12Z WRF-ARW/NMM
REFLECTIVITY GUIDANCE SHOWS A BAND OF SNOW SHOWERS DEVELOPING IN
EASTERN WISCONSIN OVERNIGHT AND TRACKING TO THE SOUTHWEST THROUGH
THE REGION TOMORROW MORNING. SUBSIDENCE THEN TAKES OVER AND SHOULD
HELP TO CLEAR SKIES OUT A BIT GOING INTO THE AFTERNOON...BUT
TEMPERATURES WILL STRUGGLE TO CLIMB MUCH WITH 850MB TEMPERATURES
AROUND -15C.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 309 PM CDT TUE MAR 11 2014

THE NEXT CHANCE FOR SOME LIGHT SNOW COMES IN ON WEDNESDAY
NIGHT/EARLY THURSDAY MORNING AS A RIDGE OF HIGH PRESSURE PUSHES TO
THE EAST AND SOME LOW LEVEL WARM AIR ADVECTION SWINGS THROUGH THE
REGION. THERE ARE SOME DIFFERING OPINIONS BETWEEN THE 11.12Z
NAM/GFS/ECMWF/GEM WITH THIS BAND AND HOW STRONG THE WAA WILL BE.
THE GFS IS THE FASTEST WITH HAVING THE SNOW COME IN ON WEDNESDAY
EVENING WHILE THE NAM IS A TAD SLOWER AND STRONGER WITH THE WAA
AND PRODUCES A LITTLE MORE QPF. THE ECMWF/GEM ARE BOTH MUCH WEAKER
WITH THIS SYSTEM AND HARDLY SHOW ANY QPF AT ALL...SO THERE IS SOME
UNCERTAINTY WITH WHETHER ANYTHING WILL OCCUR FROM THIS. COBB DATA
FROM THE GFS/NAM WOULD SAY A HALF INCH OF ACCUMULATION OR LESS IF
THE SNOW DOES OCCUR.

TEMPERATURES WILL CLIMB BACK TOWARD NORMAL THURSDAY WITH
SOUTHWESTERLY SURFACE WINDS. A WEAK COLD FRONT WILL COME THROUGH
ON FRIDAY THOUGH TEMPERATURES SHOULD NOT DROP MUCH UNTIL THE
WEEKEND COMES AND NORTHWESTERLY FLOW ALOFT SETS UP. REMOVED THE
CHANCES FOR PRECIPITATION ON SUNDAY AS IT LOOKS LIKE THE SHORT
WAVE TROUGH DIVING SOUTH OUT OF SOUTH CENTRAL CANADA WILL RUN TO
THE WEST OF THE REGION. THE BETTER CHANCES APPEAR TO COME ON
TUESDAY AS THE 11.12Z ECMWF BRINGS A SYSTEM OUT OF THE PLAINS AND
TO THE SOUTH OF THE UPPER MISSISSIPPI RIVER VALLEY. THE 11.12Z GFS
IS MUCH FURTHER TO THE NORTH WITH THIS SYSTEM AND WOULD BRING
WARMER AIR INTO THE REGION. QUITE A BIT OF UNCERTAINTY OUT
THERE...BUT ENOUGH TO WARRANT SOME CHANCES FOR PRECIPITATION ON
TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1041 PM CDT TUE MAR 11 2014

CLOUDS EXTENDING ACROSS NORTHERN MINNESOTA...NORTHERN WISCONSIN
AND UPPER MICHIGAN CONTINUE TO MARCH SOUTHWARD TOWARDS THE TAF
SITES...BROUGHT SOUTH ON A NORTHERLY BREEZE. ONE CHANGE IS THAT
ALL OBSERVATION SITES ARE REPORTING VFR CONDITIONS WITH THESE
CLOUDS. BELIEVE THIS IS A RESULT OF DRIER AIR ACCOMPANYING THE
BREEZE WHICH IS EVIDENT BY FALLING DEWPOINTS. THEREFORE...THE TAF
FORECAST STILL REFLECTS THE LOWER CLOUDS COMING THROUGH BUT BASES
ARE NOW VFR. THE VFR CONDITIONS ARE LIKELY TO PERSIST THROUGH THE
EVENING HOURS. TOWARDS 06Z WEDNESDAY NIGHT...THERE ARE INDICATIONS
OF SOME SNOW THAT COULD MOVE INTO RST FROM THE WEST...BUT THE BULK
OF THE PRECIPITATION LOOKS TO HOLD OFF UNTIL AFTER THE TAF PERIOD.

REGARDING WINDS...SPEEDS WILL STAY SUSTAINED 10 TO 15 KT
TODAY...STRONGEST THIS MORNING...DUE TO A RELATIVELY TIGHT
PRESSURE GRADIENT IN PLACE. EXPECT THE WINDS TO DIMINISH THIS
AFTERNOON AND EVENING AS HIGH PRESSURE BRIEFLY BUILDS IN.

&&

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

$$

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