Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 150441
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1140 PM CDT MON APR 14 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM CDT MON APR 14 2014

THE FOCUS FOR TONIGHT INTO TUESDAY IS ON TEMPERATURES AND THE
OFF-CHANCE THAT SOME OF THE FLURRIES/SNOW SHOWERS UP TO THE
NORTHWEST STICK AROUND INTO OUR AREA.

STRONG NORTHERLY COLD AIR ADVECTION IS OCCURRING ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY IN THE WAKE OF A LOW PRESSURE SYSTEM THAT
CAME THROUGH YESTERDAY. WHILE THE MAIN SNOW HAS SHIFTED TO THE
EAST...THE COLD AIR ADVECTION HAS LEAD TO SOME STEEP LOW LEVEL
LAPSE RATES AND AN EXPANSIVE CU FIELD THAT EXTENDS BACK UP THROUGH
THE DAKOTAS AND ONTARIO. WHILE THERE ARE QUITE A BIT OF RADAR
RETURNS SEEMING TO SHOW A LOT OF SNOW SHOWER ACTIVITY ACROSS THIS
REGION...THERE HAVE NOT BEEN MANY REPORTS OF SNOW REACHING THE
GROUND THANKS TO THE DRY LOW LEVELS. LOCAL RADAR RETURNS HAVE
FIZZLED AS THEY APPROACH KARX...SO THINK THAT THESE RETURNS ARE
MAINLY ELEVATED. THUS...HAVE KEPT THE FORECAST DRY THROUGH TONIGHT
BUT CAN NOT COMPLETELY RULE OUT A FEW FLURRIES.

TEMPERATURE-WISE...A POOL OF -15C 850MB AIR WILL DROP DOWN INTO
THE REGION TONIGHT AND WILL CAUSE TEMPERATURES TO DROP INTO THE
TEENS AND LOW 20S THROUGHOUT THE REGION...WHICH IS NEAR-RECORD
LOW LEVELS. 850MB TEMPERATURE ANOMALIES ARE AROUND -2 DEVIATIONS
FROM NORMAL...WHICH IS TYPICAL OF NEAR-RECORD LOWS. TEMPERATURES
LIKELY WILL NOT RISE MUCH ON TUESDAY WITH COLD LOW LEVEL AIR MASS
NOT RETREATING TO THE EAST UNTIL LATER IN THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM CDT MON APR 14 2014

THE MAIN FOCUS THROUGH THE MID PART OF THE WEEK ON INTO THE
WEEKEND IS WITH THE PRECIPITATION CHANCES INCLUDING THE POTENTIAL
FOR HEAVY SNOW IN NORTH CENTRAL WISCONSIN ON WEDNESDAY.

A MID LEVEL TROUGH WILL DIVE DOWN OUT OF SOUTH CENTRAL CANADA
TUESDAY NIGHT AND WILL TRACK THROUGH THE UPPER MISSISSIPPI RIVER
VALLEY WEDNESDAY INTO WEDNESDAY EVENING. SNOW LOOKS LIKE IT WILL
DEVELOP INITIALLY EARLY WEDNESDAY MORNING ACROSS CENTRAL
MINNESOTA AND NORTHERN WISCONSIN ALONG THE LOW LEVEL WARM AIR
ADVECTION BAND. DIFFERENCES STILL EXIST BETWEEN THE 14.12Z
NAM/GFS/ECMWF/GEM WITH HOW INTENSE THIS FORCING WILL BE AND WHERE
IT WILL BE EARLY ON. THE ECMWF CONTINUES TO BE THE WEAKEST EARLY
ON AND KEEPS ANY SNOW OFF TO THE NORTHWEST WHILE THE GEM/GFS BOTH
ARE MORE ROBUST WITH THE SNOW AND DEVELOPS IT ALL THE WAY DOWN
INTO NORTHEAST IOWA. MEANWHILE...THE NAM IS DRIER AND MORE SIMILAR
TO THE ECMWF EARLY ON. AS THE TROUGH MOVES IN...THE QUESTION IS
WITH HOW FAR NORTH THE ABOVE FREEZING WARM LAYER WILL MAKE IT
ACROSS WESTERN WISCONSIN ON WEDNESDAY WITH PRECIPITATION TYPE
LIKELY BEING ALL SNOW TO THE NORTH OF THIS WARM LAYER. TAYLOR
COUNTY LOOKS THE MOST LIKELY TO BE UNDER THE MOST SNOW...SO
CONSIDERED GOING WITH A WINTER STORM WATCH THERE BUT CONFIDENCE IS
NOT HIGH ENOUGH THAT THERE WILL BE OVER 6 INCHES WITH THE
POTENTIALLY WARMER AIR THERE. WILL HAVE TO MONITOR LATER FORECASTS
WITH A WINTER WEATHER ADVISORY POSSIBLE WITH ABOUT 3-5 INCHES
CURRENTLY FORECAST FOR TAYLOR COUNTY.

NOT MUCH OF A WARM SECTOR AHEAD OF THIS LOW WITH LITTLE OR NO
INSTABILITY THERE AS THE COLD FRONT SWINGS THROUGH...SO MOST OF
THE PRECIPITATION SHOULD STAY ALONG AND NORTH OF THE SURFACE
LOW/MID LEVEL TROUGH. PRECIPITATION HAS TRENDED FURTHER TO THE
SOUTH ON THURSDAY INTO THURSDAY NIGHT. THE 14.12Z ECMWF HAS
TRENDED EVEN FURTHER TO THE SOUTHEAST AND WOULD LEAVE THE REGION
DRY FOR THIS PERIOD NOW...SO THERE STILL IS QUITE A BIT OF
UNCERTAINTY HERE. BEYOND THAT...ANOTHER POTENTIAL TROUGH COMES
THROUGH SATURDAY NIGHT INTO SUNDAY WITH THE 14.12Z BEING THE
DEEPEST/FURTHEST SOUTH WITH IT WHILE THE ECMWF HAS MAINLY ZONAL
FLOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM CDT MON APR 14 2014

PASSAGE OF UPPER TROUGH AND RELATED SUBSIDENCE HAS CLEARED SKIES OUT
EXCEPT FOR A FEW HIGH BASED STRATUS IN NORTHWEST FLOW. VFR
CONDITIONS SHOULD PREVAIL INTO TUESDAY NIGHT AS SURFACE RIDGE PASSES
THROUGH.

ENERGY COMING INTO PACIFIC NORTHWEST AND SOUTHWEST CANADA WILL BEGIN
TO DROP INTO THE NORTHERN ROCKIES LATE ON TUESDAY AND BEGIN TO
ADVECT MID TO HIGH LEVEL CLOUDS IN. INTRODUCED SOME HIGH BASED
CEILINGS LATE IN FORECAST AHEAD OF NEXT SYSTEM BUT STILL VFR.

&&

.HYDROLOGY...
ISSUED AT 322 PM CDT MON APR 14 2014

WHILE HEAVY RAIN HAS ENDED ACROSS THE REGION...RIVERS REMAIN
ELEVATED FROM THE RAIN THAT FELL OVER THE PAST FEW DAYS. A NUMBER
OF SITES ALONG THE KICKAPOO RIVER ARE JUST BELOW FLOOD STAGE AND
ARE EXPECTED TO GO INTO FLOOD STAGE OVER THE NEXT DAY.
OTHERWISE...SOME SITES ALONG THE MISSISSIPPI ARE RISING AND ARE
EXPECTED TO GO INTO FLOOD STAGE LATER THIS WEEK. WHILE CONDITIONS
WILL BE DRY INTO TUESDAY...A PAIR OF SYSTEMS WILL MOVE THROUGH THE
REGION LATER IN THE WEEK AND COULD PROVIDE SOME ADDITIONAL RAIN OR
SNOW.

&&

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

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...SHEA
HYDROLOGY...HALBACH



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