083
FXUS63 KARX 040615
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1215 AM CST WED MAR 4 2026
KEY MESSAGES
- FOG EXPECTED OVERNIGHT, PRIMARILY WEST OF THE MISSISSIPPI
WITH SOME DENSE FOG EXPECTED AS WELL.
- RAIN CHANCES RETURN THURSDAY (20 TO 40%), MOSTLY IMPACTING
PORTIONS OF NORTHEAST IOWA AND SOUTHWESTERN WISCONSIN HOWEVER
AMOUNTS REMAIN BELOW 0.2".
- RAIN VERY LIKELY (95%) FOR FRIDAY MORNING AND THUNDERSTORMS -
PERHAPS SEVERE - FOR FRIDAY EVENING. THERE IS A 35 TO 85%
CHANCE (HIGHEST IN NE IA AND SW WI) FOR AT LEAST 1" OF RAIN TO
FALL FRIDAY INTO SATURDAY.
DISCUSSION
ISSUED AT 1214 AM CST WED MAR 4 2026
FOG OVERNIGHT
CLEAR SKIES AND LIGHT WINDS HAVE LED TO POTENTIAL FOR FOG OVERNIGHT
WITH CONCERNS FOR DENSE (AT OR UNDER 1/4 OF A MILE) FOG FOCUSING ON
LOCATIONS WEST OF THE MISSISSIPPI, PARTICULARLY LOCATIONS WITH
SNOWPACK. HAVE ISSUED A DENSE FOG ADVISORY FOR AREAS WITH SNOW PACK
AND FARTHER WEST TOWARD SOUTH CENTRAL MN AND NORTH CENTRAL IA, WHERE
OBSERVATIONS AT MULTIPLE LOCATIONS ARE AT A 1/4 OR LESS AS OF 10 PM.
LOW POTENTIAL FOR RAIN THURSDAY IN NORTHEAST IOWA AND SOUTHWEST
WISCONSIN
WEDNESDAY IN TO THURSDAY, WAVE CURRENTLY OVER COLORADO MOVES JUST TO
OUR SOUTH AS IT TREKS TOWARD SOUTHERN ONTARIO. WITH SURFACE RIDGING
PRESENT IN THE SOUTHEAST CONUS, SOUTHERLY MOIST FETCH AT THE SURFACE
AND 850MB SHOULD BRING ENOUGH NORTHWARD FOR WIDESPREAD PRECIP TO
DEVELOP ACROSS THE OH VALLEY WITH THE NORTHWESTERN EDGE OF THE
PRECIP SHIELD POTENTIALLY GRAZING NE IA AND SW WI. 04.00Z HREF AND
04.01Z NBM CONTINUE TO MAINTAIN A 20-40% CHANCE FOR PRECIP SO HAVE
CONTINUED TO MAINTAIN THIS IN THE FORECAST. SHOULD RAIN OCCUR,
AMOUNTS WILL BE LOW WITH 04.00Z HREF MAX VALUES UP TO ONLY 0.2".
RAIN VERY LIKELY FRIDAY MORNING, POTENTIAL FOR SEVERE STORMS
EVENING, UNCERTAIN NIGHTTIME INTO SATURDAY
STRONG UPPER WAVE CURRENTLY HEADING FOR THE PACIFIC NORTHWEST LOOKS
TO BREAK OVER THE FOUR CORNERS FRIDAY AND BARRELS TOWARD LAKE
SUPERIOR. WITH SURFACE RIDGING STILL FIRMLY IN PLACE IN THE SE
CONUS, CONTINUE SOUTHERLY MOIST ADVECTION ACROSS THE CENTRAL CONUS
WILL SET THE STAGE FOR WIDESPREAD RAIN WITH VIRTUALLY ALL GUIDANCE
DEPICTING THIS OCCURRING FRIDAY MORNING IN THE DRIFTLESS REGION WITH
ADDITIONAL RAIN LIKELY DURING THE EVENING INTO SATURDAY. 04.12Z MEAN
PWAT VALUES CLIMB TO AROUND 1" BEFORE THE RAIN ARRIVES, JUST BELOW
MODEL CLIMATOLOGY MAXIMUMS FOR THIS TIME OF YEAR. 04.01Z NBM
PROBABILITIES GENERALLY DEPICT A 35 TO 85% CHANCE FOR 1" OF RAIN
ACROSS FRIDAY AND SATURDAY WITH CHANCES TOWARD THE HIGH END OF THAT
RANGE IN NE IA AND SW WI. GIVEN POTENTIAL FOR FROZEN GROUND
- 6 TO 17 INCHES OF FROST DEPTH WERE OBSERVED MONDAY AND TUESDAY -
ADDITIONAL RUNOFF COULD LEAD TO RISES ON CREEKS AND STREAMS.
HOWEVER, AFTERNOON HIGHS IN THE 40S AND 50S WEDNESDAY AND THURSDAY
MAY HELP THAW THINGS BEFORE THE RAIN ARRIVES.
ASIDE FROM RISES ON RIVERS, OTHER POTENTIAL HAZARD LOOKS TO BE
SEVERE THUNDERSTORMS. WITH STRONG WINDS EXPECTED ALOFT, FOCUS WILL
BE ON WHERE SUFFICIENT INSTABILITY IS PRESENT FOR THUNDERSTORMS TO
DEVELOP AND POTENTIALLY TAP INTO SAID SEASONABLY STRONG SHEAR. IN
SHORTER TERMS, MUCH DEPENDS ON HOW FAR NORTH THE WARM FRONT ADVANCES
AND GUIDANCE CONTINUES TO DIFFER QUITE A BIT ON THIS. ILLUSTRATIVE
ARE THE 04.00Z OPERATIONAL RUNS OF THE GFS AND NAM WHICH BRING THE
WARM SECTOR TO ENCOMPASS MOST OF THE CWA AND JUST
FAYETTE/CLAYTON/GRANT COUNTIES, RESPECTIVELY. CSU-ML PROBABILITIES
BASED ON THE GEFS SUGGEST SOME CHANCE ACROSS VIRTUALLY THE WHOLE CWA
WHILE 03.12Z ECENS JOINT MUCAPE-SHEAR PROBABILITY VALUES SUFFICIENT
FOR ORGANIZED CONVECTION ARE AROUND 15% IN TAYLOR COUNTY INCREASING
TO NEAR 60% IN OUR SOUTH. WILL NEED TO CLOSELY MONITOR THIS PERIOD
AS, GIVEN DEEP SHEAR VALUES UPWARDS OF 50 KNOTS AND SEASONABLY COLD
TEMPS ALOFT, SEVERE HAIL SEEMS PLAUSIBLE SHOULD THE WARM FRONT REACH
OUR CWA AND THUNDERSTORMS DEVELOP.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1112 PM CST TUE MAR 3 2026
LIFR TO BELOW AIRFIELD MINIMUM VSBYS ARE EXPECTED AT KRST WITH AREAS
OF 1/4SM FOG DEVELOPING ACROSS PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA PRIOR TO SUNRISE. GIVEN THE HIGH PROBABILITIES
(60-80%) IN THE RECENT HREF FOR 1/4SM AT KRST IN COMBINATION
WITH CALM WINDS, CLEAR SKIES AND A PRONOUNCED NOCTURNAL
INVERSION IN THE RAP/HRRR, THINKING A PERIOD OF 1/4SM IS LIKELY
TO OCCUR. HOWEVER, AS DAYBREAK OCCURS AND DIURNAL MIXING
PROCESSES TAKE PLACE, EXPECTING THE FOG LAYER TO LIFT FAIRLY
QUICKLY BY MID-MORNING LEAVING BEHIND VFR CONDITIONS. AS YOU
HEAD CLOSER TO THE MISSISSIPPI RIVER, PROBABILITIES DECREASE FOR
1/4SM VSBYS FOR PORTIONS OF WESTERN WI WITH ONLY LOW
PROBABILITIES (20-30%) IN THE HREF AT KLSE. AS A RESULT, HAVE
MAINTAINED IFR REDUCTIONS FROM THE PREVIOUS FORECAST BUT THERE
IS SOME POTENTIAL (40% CHANCE) FOR NO VSBY REDUCTIONS AT KLSE.
IN ANY CASE, VFR CONDITIONS ARE EXPECTED AFTER THIS FOG LIFTS
MID-MORNING ACROSS THE AREA AND LIKELY STAY VFR FOR THE
REMAINDER OF THE TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ086-087-
094>096.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011-
018-019-029.
DISCUSSION...FERGUSON
AVIATION...NAYLOR
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