053
FXUS63 KARX 171730
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1130 AM CST SUN NOV 17 2024
KEY MESSAGES
- ACTIVE WEATHER FOR THE UPCOMING WEEK WITH POTENTIAL FOR
RAINFALL EXCEEDING 1" (MON-TUE-EC/GEFS/CANADIAN ENSEMBLES
40-80% PROBABILITY).
- TURNING COLDER WEDNESDAY INTO THE WEEKEND
WITH HIGHS IN THE 30S AND 40S. SOME POTENTIAL FOR RAIN/SNOW
MIDWEEK (40-70% PROBABILITY FOR MEASURABLE SNOW OF 0.1" OR
MORE, BUT WILL NEED TO CONTINUE TO ASSESS). STILL BREEZY
SEVERAL DAYS THIS WEEK.
UPDATE
ISSUED AT 1130 AM CST SUN NOV 17 2024
THE FORECAST FOR MONDAY AND MONDAY NIGHT REMAINS ON TRACK WITH
RAIN OVERSPREADING THE AREA FROM SOUTH TO NORTH MAINLY MONDAY
AFTERNOON. MONDAY MORNING WILL BE DRY FOR THE KIDS AT THE BUS
STOP. AMOUNTS STILL LOOK ON TRACK TO BE AT LEAST AN INCH
AREAWIDE. THE 17.12Z HREF 25-75TH PERCENTILE RANGE IS THE
HIGHEST ACROSS SOUTHWEST WI AT 1-1.5" - THE AREA THAT SEEMS TO
HAVE THE BEST ACCESS TO SOME MUCAPE IN THE 300-500 J/KG RANGE
PER THE LATEST RAP. THE 90TH PERCENTILE /WORST CASE SCENARIO/ FROM
VIROQUA S-SWWRD TOWARD CEDAR RAPIDS IA IS AROUND 2".
DISCUSSION
ISSUED AT 351 AM CST SUN NOV 17 2024
OVERVIEW:
THE CLOUDS LIMITED HIGHS SATURDAY TO THE MID 40S TO LOWER 50S, BUT
STILL ABOVE NORMAL TEMPERATURES. ISOLATED THUNDERSTORMS DID DEVELOP
OVER NORTHEAST IOWA INTO SOUTHERN WISCONSIN AND ALSO WITH A
SECONDARY LINE LATER IN THE EVENING AS THE SHOWERS INCREASED OVER
PARTS OF JUNEAU AND ADAMS COUNTIES. WIND GUSTS RANGED FROM 25 TO
35 MPH FOR WISCONSIN TO 35 TO 45 MPH FOR PARTS OF IOWA AND
MINNESOTA. THE STRONGER WIND GUSTS WERE AT RST, BYRON, AND
PRESTON. THE LATEST SUBJECTIVE SURFACE ANALYSIS HAD AN OCCLUDED
FRONT OVER EASTERN MINNESOTA WITH A WARM FRONT TOWARD KOLZ AND
MLI. SOME PATCHY LIGHT RAIN CONTINUED OVER PARTS OF SOUTHERN
WISCONSIN WITH THE AREA OF FRONTOGENESIS/VORTICITY ADVECTION.
THE 500MB TROUGH WAS STILL TO THE WEST OVER THE DAKOTAS.
RAINFALL AMOUNTS HAVE BEEN LIGHT, GENERALLY 0.05" OR LESS. THE
WSR-88D RADAR ESTIMATES SHOW THERE MAY HAVE BEEN SOME SPOTTY
0.05 TO 0.15" AMOUNTS WITH THE STRONGER SHOWERS/STORMS. THE
LATEST GOES NIGHT MICROPHYSICS SATELLITE IMAGERY SHOWED THE
CLEARING SKIES AT RST WITH CLOUDS TO THE EAST AND WRAP-AROUND
CLOUDS ACROSS NORTHERN MINNESOTA.
ACTIVE WEATHER FOR THE UPCOMING WEEK WITH POTENTIAL FOR
RAINFALL EXCEEDING 1" (MON-TUE-EC/GEFS/CANADIAN ENSEMBLES
40-80% PROBABILITY). TURNING COLDER WEDNESDAY INTO THE WEEKEND
WITH HIGHS IN THE 30S AND 40S. SOME POTENTIAL FOR RAIN/SNOW
MIDWEEK (40-80%) PROBABILITY FOR MEASURABLE SNOW OF 0.1" OR
MORE, BUT WILL NEED TO CONTINUE TO ASSESS):
WATER VAPOR SATELLITE IMAGERY AND HEIGHTS SHOWED THE FULL LATITUDE
TROUGH STRETCHING FROM ONE CLOSED LOW OVER SOUTHERN CANADA/NORTH
DAKOTA AND ANOTHER CLOSED LOW OVER THE SOUTHWEST U.S. AND A RIDGE TO
THE EAST AND THE WEST OF THIS TROUGH. THROUGH TODAY, THE SOUTHERN
PART OF THE FORECAST AREA COULD GET CLIPPED WITH MORE SPRINKLES WITH
MID LEVEL MOISTURE/VORTICITY ADVECTION LINGERING TODAY. THE CLOSED
LOW LIFTS FARTHER NORTH INTO ONTARIO. THE HREF KEEPS THINGS DRY
AND THE RAP DRIES OUT THE 850MB LAYER AFTER 12 OR 13Z, THUS
WILL KEEP THE MEASURABLE POPS SOUTH OF THE AREA. TEMPERATURES
ARE STARTING OUT MILD AND WITH MORE SUNSHINE, ARE LOOKING FOR
HIGHS IN THE UPPER 40S TO LOWER 50S.
TONIGHT INTO TUESDAY, THE CLOSED LOW OVER THE SOUTHWEST U.S.
WILL LIFT NORTHEAST THROUGH THE PLAINS, DEEPENING , BECOMING
NEGATIVELY TILTED, AND MERGING WITH THE TROUGH OVER THE PACIFIC
NORTHWEST. 850 MB MOISTURE TRANSPORT VECTORS SHOW A MARKED
INCREASE FROM MONDAY 12Z TO 18Z ACROSS IOWA AND THE MOISTURE
TRANSPORT STRENGTHEN ACROSS THE MISSISSIPPI VALLEY THROUGH
MONDAY NIGHT. IN RESPONSE TO THIS, PRECIPITABLE WATER VALUES OF
LESS THAN 0.50" CLIMB TO 1 TO 1.25". THE 17.00Z NAEFS SHOWS
THIS IS 3 TO 4 STANDARD DEVIATIONS ABOVE NORMAL. THE
PRECIPITATION SHIELD IS FORECAST TO OVERSPREAD THE FORECAST AREA
FROM SOUTH TO NORTH DURING THE DAY MONDAY, DECREASING FROM SOUTH
TO NORTH DURING THE DAY TUESDAY. THE EFI CONTINUE TO SHOW
ANOMALOUS PRECIPITATION WHEN COMPARED TO CLIMATOLOGY WITH THE
SHIFT OF TAILS 1 TO 2 OVER CENTRAL MINNESOTA AND EASTERN
DAKOTAS. THE ECMWF, CANADIAN, AND GEFS ENSEMBLES CONTINUE TO
SHOW HIGH PROBABILITIES (40-80%) FOR 1" OF RAINFALL FOR THE
FORECAST AREA. CANNOT RULE OUT ISOLATED THUNDERSTORMS WITH THE
STRONGER MOISTURE TRANSPORT. MUCAPE VALUES SHOWS LIMITED
INSTABILITY WITH POCKETS OF 100 OR 150 J/KG. BOTH SPC/CSU
SEVERE WEATHER PROBABILITIES REMAIN SOUTH OF THE FORECAST AREA
MONDAY. DID NOTICE SPC ADDED A GENERAL THUNDER AREA FOR TUESDAY
AS THE UPPER LEVEL TROUGH BECOMES NEGATIVELY TILTED. WITH THE
CAPE WEAKENING OVER THE AREA, HAVE LEFT OUT THUNDER MENTION ON
TUESDAY FOR NOW. COLDER AIR EVENTUALLY WRAPS INTO THE SYSTEM
THROUGH THE DAY TUESDAY. IF THERE IS STILL ANY PRECIPITATION, IT
COULD TRY TO MIX WITH SNOW. WE CURRENTLY HAVE HIGHS IN THE
UPPER 40S AND 50S THROUGH TUESDAY. WILL NEED TO MONITOR THIS
THOUGH AS THIS TIME OF YEAR, CLOUDS AND PRECIPITATION CAN LIMIT
THE HIGHS.
WPC HAS MUCH OF AREA IN THE 5% RISK FOR EXCESSIVE RAINFALL. THE 6-
HR RAINFALL FLASH FLOOD GUIDANCE IS GENERALLY 2.25" TO 3", SO WITH
NO FROST IN THE GROUND, WE SHOULD BE ABLE TO HANDLE THE RAIN THAT IS
BEING FORECAST.
AS THE LARGE CLOSED LOW LINGERS OVER THE UPPER MISSISSIPPI VALLEY
WEDNESDAY AND FINALLY MOVES EAST THURSDAY, A RAIN/SNOW MIX IS
FORECAST WEDNESDAY INTO THURSDAY. THE TRACK COULD STILL CHANGE
THROUGH WEDNESDAY AND THURSDAY, BUT THE 17.00Z ECE/GEFS/CANADIAN
ENSEMBLES HAVE A 40 TO 70% CHANCE OF MEASURABLE SNOW (0.1" OR MORE)
OF SNOW AND 20-40% PROBABILITY OF 1" OR MORE.
MUCH COOLER TEMPERATURES FOR WEDNESDAY INTO THE WEEKEND WITH
HIGHS IN THE 30S AND 40S. BRISK WIND GUSTS ARE STILL FORECAST
FOR MUCH OF THE WEEK.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1130 AM CST SUN NOV 17 2024
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD WITH WEATHER
INCREASING MONDAY AFTERNOON AND INTO THE OVERNIGHT.
IT IS EXPECTED THAT MVFR CONDITIONS WILL OVERSPREAD THE AREA
FROM SOUTH TO NORTH MONDAY WITH IFR CIGS FOLLOWING SHORTLY
BEHIND...POSSIBLY WITHIN 3 HOURS. TIMING OF THE MVFR CEILING
ONSET LOOKS TO BE 16-18Z ACROSS SOUTHWEST WI AND NORTHEAST
IOWA...ARRIVING IN THE NORTH CENTRAL WI /KAUW/ VICINITY 22-00Z.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
UPDATE...BAUMGARDT
DISCUSSION...ZAPOTOCNY
AVIATION...BAUMGARDT
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