Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KARX 231829
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1229 PM CST SUN NOV 23 2014

.UPDATE...
ISSUED AT 1225 PM CST SUN NOV 23 2014

WITH OBSERVATIONS AND LAW ENFORCEMENT BOTH SUGGESTING VISIBILITIES
ARE NEAR ZERO IN FOG ACROSS NRN WI...A COLLABORATED EXTENSION TO
THE DENSE FOG ADVISORY WAS COMPLETED TO 6 PM TODAY. WITH VERY
MOIST BOUNDARY LAYER AND SNOW PACK MELTING...NO REASON TO BELIEVE
THIS DENSE FOG WILL IMPROVE SOON. ANOTHER EXTENSION MAY BE
NEEDED.

ALSO...IN REVIEW OF THE LATEST MODEL GUIDANCE WHICH CONTAINS A
LARGE SPREAD FOR THE NEXT 36 HOURS STILL...THERE SEEMS TO BE SOME
AGREEMENT ON A FURTHER SOUTH TRACK TO CURRENT ENERGY ACROSS THE
INTERMOUNTAIN WEST. THIS ENERGY EJECTS NORTHEAST INTO THE GREAT
LAKES AND CAUSES ACCUMULATING SNOW ACROSS NRN IL/SRN WI FOR
MONDAY. THIS SOUTHERN EMPHASIS IS A BIT MORE AGREED UPON IN THE
23.12Z MODEL GUIDANCE...WHICH WOULD REDUCE CENTRAL WISCONSIN
SNOWFALL TOTALS AND SHIFT THEM SOUTH. AN ADVISORY MAY BE NEEDED
FOR THE COMBINATION OF SNOW AND BLOWING SNOW FOR PARTS OF THE
SOUTHERN FORECAST AREA.
&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST SUN NOV 23 2014

CHALLENGES INCLUDE RAIN CHANCES AND AMOUNTS TODAY...THE CHANGE OVER
TO SNOW TONIGHT AND THEN SNOW PLACEMENT/AMOUNTS AND BLOWING SNOW
POTENTIAL LATE TONIGHT THROUGH MONDAY. FORECAST CONFIDENCE IS BELOW
AVERAGE WITH MODELS HAVING PROBLEMS RESOLVING HOW THE NORTHERN AND
SOUTHERN STREAM WAVES WILL CONVERGE AND INTERACT TONIGHT THROUGH
MONDAY ACROSS THE UPPER MIDWEST.

23.09Z WATER VAPOR LOOP SHOWS A CLOSED LOW ACROSS SOUTHERN
SASKATCHEWAN AND A SECONDARY OPEN WAVE DRAPED ACROSS THE SOUTHERN
PLAINS. AT THE SURFACE...THE PRIMARY LOW CENTER IS ACROSS SOUTHEAST
SASKATCHEWAN WITH A STATIONARY FRONT EXTENDING TO THE SOUTHEAST
ACROSS EASTERN ND. THE COLD FRONT DROPS SOUTH ACROSS EASTERN SD INTO
CENTRAL NE AND THE WARM FRONT EXTENDS TO THE EAST ACROSS CENTRAL MN
INTO WEST CENTRAL WI. EXPECT PERIODS OF LIGHT TO MODERATE RAIN TO
RAPIDLY DEVELOP LATER THIS MORNING IN THE WARM SECTOR OF THIS SYSTEM
WITHIN REGION OF BROAD ISENTROPIC LIFT AND STRONG MOISTURE ADVECTION
AHEAD OF THE APPROACHING COLD FRONT. EXPECT ACCUMULATING RAINFALL
ACROSS THE ENTIRE FORECAST AREA TODAY...BUT HIGHEST AMOUNTS WILL
FALL ACROSS NORTHEAST IA INTO SOUTHWEST WI WHERE OVER 0.75 INCHES
ARE POSSIBLE. AMOUNTS WILL DROP OFF TO AROUND A TENTH FARTHER NORTH
AND WEST. TEMPERATURES WILL BE VERY WARM TODAY WITH AFTERNOON HIGHS
IN THE UPPER 40S TO LOWER 50S. WHAT REMAINING SNOWPACK IS LEFT WILL
MELT AND CAUSE ADDITIONAL AREAS OF FOG...ESPECIALLY ACROSS NORTH
CENTRAL WI. A STRONG COLD FRONT SWEEPS ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY TONIGHT. PRECIP WILL QUICKLY CHANGE FROM RAIN TO SNOW
FROM WEST TO EAST BETWEEN 24.06Z AND 24.12Z WITH TEMPERATURES
DROPPING BELOW FREEZING.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CST SUN NOV 23 2014

23.00Z MODELS DIVERGE INTO TWO DISTINCT CAMPS CONCERNING PLACEMENT
AND AMOUNTS OF HIGHEST SNOWFALL ON MONDAY. THIS IS MOST APPARENT
LOOKING AT 500 HPA HEIGHTS. AS THE SOUTHERN STREAM WAVE LIFTS
NORTHEASTWARD AND BEGINS TO INTERACT WITH THE CLOSED LOW ACROSS
THE SOUTHERN CANADIAN PRAIRIES...THE GFS/ECMWF DEVELOP A SECONDARY
LOW ACROSS EASTERN LAKE SUPERIOR BY 24.12Z AND THEN QUICKLY LIFT
IT INTO EASTERN ONTARIO BY 25.00Z. THE NAM/GEM ON THE OTHER HAND
DEVELOP THE SECONDARY LOW BY 24.18Z ACROSS CENTRAL WI AND ARE MUCH
SLOWER LIFTING IT INTO CANADA. AS A RESULT...THE GFS/ECMWF
DEFORMATION SNOW BAND SETS UP ACROSS EASTERN IA/NORTHERN
IL/SOUTHERN WI WITH MINIMAL ACCUMULATIONS ACROSS THE FORECAST
AREA. THE NAM/GEM DEFORMATION SNOW BAND IS FARTHER NORTH AND
WEST...DROPPING AS MUCH AS 4 TO 6 INCHES OR MORE ACROSS A LARGE
SWATH OF THE FORECAST AREA. THESE DIFFERENCES ARE FURTHER
ILLUSTRATED LOOKING AT THE 23.21Z SREF PLUME FOR LA CROSSE WITH
ITS MEMBERS GENERATING ANYWHERE FROM 0 TO 17 INCHES OF SNOW
THROUGH TUESDAY MORNING.

CONFIDENCE CERTAINLY NOT HIGH ENOUGH TO HOIST A WINTER STORM WATCH
AND WILL INSTEAD FOLLOW A MIDDLE-OF-THE-ROAD APPROACH WITH MOST
AREAS SEEING SOME SNOW ACCUMULATION THROUGH MONDAY NIGHT. THINK
HIGHEST AMOUNTS BETWEEN 3 TO 5 INCHES WILL FALL EAST OF THE
MISSISSIPPI RIVER CLOSEST TO THE DEEPEST MOISTURE AND STRONGEST LIFT
NEAREST THE TRACK OF THE MID-LEVEL CIRCULATION. ELSEWHERE...1 TO 3
INCHES ARE POSSIBLE. WILL HIGHLIGHT SNOW POTENTIAL AND UNCERTAINTY
IN A SPS...BUT WILL NEED TO WATCH THIS SYSTEM CAREFULLY AS ANY
SHIFT TOWARDS ONE OF THE TWO MODEL SCENARIOS COULD DRASTICALLY
ALTER SNOWFALL FORECAST. OF GREATER CERTAINTY MONDAY ARE STRONG
NORTHWEST WINDS WITH GUSTS AS HIGH AS 35 MPH ACROSS PORTIONS OF
SOUTHEAST MN AND NORTHEAST IA. BLOWING SNOW A POSSIBILITY REGION-
WIDE...BUT WILL BE DEPENDENT ON AREAS THAT RECEIVE THE MOST
ACCUMULATION.

TUESDAY INTO THE UPCOMING THANKSGIVING HOLIDAY WEEKEND WILL BE
MARKEDLY COLDER WITH DAILY HIGHS GENERALLY IN THE UPPER TEENS AND
20S. THE EXCEPTION BEING WEDNESDAY WHEN HIGHS WILL BE IN THE LOWER
30S AS THE THERMAL PROFILE BRIEFLY WARMS AHEAD OF AN APPROACHING
SHORT-WAVE ALOFT. WITH THIS WAVE...HOWEVER...COMES THE NEXT CHANCE
FOR ACCUMULATING SNOWFALL TUESDAY NIGHT THROUGH WEDNESDAY. AT THIS
TIME...A FEW INCHES OF SNOW ARE POSSIBLE...BUT PERSONS WITH
HOLIDAY TRAVEL PLANS SHOULD PAY CLOSE ATTENTION TO THE LATEST
FORECASTS AS ROAD CONDITIONS COULD BE IMPACTED. THANKSGIVING DAY
WILL BE COLD BUT DRY WITH HIGHS FROM THE MID TEENS INTO THE LOWER
20S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1225 PM CST SUN NOV 23 2014

LIFR /IFR/ CONDITIONS ARE EXPECTED TO CONTINUE AT KRST /KLSE/
THROUGH THE AFTERNOON UNTIL A COLD FRONT PROVIDES A WIND SHIFT AT
KRST LATER THIS AFTERNOON. CURRENTLY THIS FRONT HAS VFR CONDITONS
BEHIND IT...HOWEVER ABUNDANT LOW-LEVEL MOISTURE AND SUNSET SUGGEST
THAT IF THERE IS A BREAK IN THE LIFR CONDITIONS AT THE TAF SITES...IT
WILL BUILD BACK IN FOR THE OVERNIGHT WITH COOLING. A CHANGE FROM
RAIN TO SNOW THEN OCCURS LATER OVERNIGHT...WITH DEEPER MIXING AND
STRONGER WINDS MOVING IN BY DAYBREAK. THIS MIXING WILL HELP
FINALLY REMOVE THE LIFR/IFR CONDITIONS...IF THEY HAVE NOT LIFTED
ACROSS THE AREA. STRONG WINDS ARE EXPECTED MONDAY AND POSSIBLY
FLURRIES.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ017-029.

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

$$

UPDATE...BAUMGARDT
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...BAUMGARDT



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.