815
FXUS63 KARX 261704
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1104 AM CST THU FEB 26 2026
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES FROM THE UPPER 40S TO LOW 50S
EXPECTED FOR FRIDAY.
- NARROW BAND OF HEAVY SNOW POSSIBLE ON SATURDAY. LONGER
FORECAST HOUR AND LIMITED COVERAGE OF HEAVIER SNOW KEEP
OVERALL CONFIDENCE LOW (<30%) AS SHIFTING IN STORM TRACK AND
LOCATION IS EXPECTED.
- WARMER TEMPERATURES RETURN THROUGH NEXT WEEK.
DISCUSSION
ISSUED AT 1215 AM CST THU FEB 26 2026
NEAR SEASONABLE TEMPERATURES TODAY:
A DEEPENING UPPER LEVEL CYCLONE OVER THE CANADIAN ROCKIES
CAUSING CYCLOGENESIS OVER THE NEXT 48 HOURS WILL DICTATE THE
LOCAL WEATHER PATTERN THROUGH SATURDAY. A QUASI DIFFLUENT
PATTERN TODAY KEEPS TEMPERATURES NEAR SEASONABLE, INFLUENCED
HEAVILY BY EARLY MORNING STRATUS AND FOG POTENTIAL, PERHAPS
WARRANTING AN AFD UPDATE LATER THIS MORNING, AS WELL AS PREEXISTING
SNOWPACK AFFECTING ALBEDO AND BUDGET OF INCOMING SOLAR
RADIATION SHOULD SKY COVER CEASE THROUGH THE AFTERNOON/EVENING.
ABOVE NORMAL TEMPERATURES FRIDAY:
AS THE EXTRATROPICAL CYCLONE SAGS EAST-SOUTHEAST WHILST PHASING
THROUGH MANITOBA CANADA ON FRIDAY, THE ACCOMPANYING TIGHTENING
WARM SECTOR USHERS IN WARMER AIR THROUGH THE UPPER MISSISSIPPI
RIVER VALLEY. RESULTANT HIGH (50%-70%) CONFIDENCE FOR DAYTIME
HIGHS PEAKING FROM THE UPPER 40S TO LOWER 50S FOR FRIDAY.
CONFIDENCE IN WARMER TEMPERATURES INTO THE UPPER 50S WANES DUE
TO COLLOCATION OF THE PREEXISTING SNOWPACK IN LOCAL
CLIMATOLOGICALLY WARMER SPOTS FROM NORTHEAST IOWA INTO WESTERN
AND SOUTHWEST WISCONSIN ON WEDNESDAY'S SATELLITE IMAGERY.
RESULTING INCREASED ALBEDO DECREASES SOLAR INSOLATION AND
DIURNAL INFLUX BUDGET. THEREFORE, SIMILAR TO PREVIOUS FORECASTS,
HAVE DECREASED DAYTIME HIGHS SLIGHTLY ON FRIDAY IN THESE AREAS
USING ENSEMBLE NBM 50TH PERCENTILE.
STRONG WINDS FRIDAY:
WHILE THE SURFACE LOW CENTER WILL BE SITUATED WELL TO THE NORTH OVER
SOUTHERN CANADA, THE TIGHTENING LOW LEVEL ISOHEIGHT GRADIENT WILL
INCREASE WINDS LOCALLY. EXACT LOW TRACK WILL DETERMINE EXTENT AND
MAGNITUDE OF STRONGEST WINDS AS CURRENT FORECAST SOUNDINGS
SUGGEST INHIBITED OFF-SURFACE MIXING FOR THE SOUTHERN HALF OF
THE FORECAST AREA WITHIN THE LOW LEVEL WAA REGIME. THEREFORE, CLIMATOLOGICALLY
WINDIER LOCATIONS WEST OF THE MISSISSIPPI RIVER VALLEY MAY BE
THROTTLED SLIGHTLY COMPARED TO WISCONSIN BASED ON THIS TRACK.
AS THE LOW TRAVERSES CENTRAL ONTARIO THROUGH FRIDAY EVENING,
IT'S SUBSEQUENT COLD SECTOR ADVECTS SOUTHEAST, GRAZING THE
UPPER MISSISSIPPI RIVER VALLEY, INCREASING STRONG WIND THREAT
LOCALLY OVERNIGHT INTO SATURDAY MORNING. CURRENT CONFIDENCE
KEEPS STRONGEST LOW LEVEL CAA JUST NORTH OF THE FORECAST AREA,
ABATING STRONGEST WINDS AT THE CURRENT FORECAST HOUR. CURRENT
CONFIDENCE FOR 25 TO 35 MPH GUSTS.
NARROW BAND OF HEAVY SNOWFALL POSSIBLE SATURDAY:
WHILE THE CURRENT TRACK ALSO SHUNTS THE PLUME OF HIGHEST
MOISTURE WELL TO THE SOUTH, LINGERING LOW TO MID LEVEL MOISTURE,
AIDED BY A SUBSEQUENT AXIS OF DILATATION, AND ENHANCED BY A LOW
TO MID LEVEL FRONTOGENESIS BAND SUPPORTS A NARROW BAND OF
POTENTIALLY HIGHER SNOWFALL LOCALLY THROUGH SATURDAY. SIMILAR TO
MOST RECENT SNOWFALL A WEEK AGO, STRONGER FORCING WILL LIKELY
USHER IN VERY NARROW BAND OF HIGHER SNOWFALL RATES WHICH /WILL/
SHIFT NORTH-SOUTH IN COMING FORECASTS. WHILE ENSEMBLE (25.12Z)
SOUNDING PLUMES SHOW A LARGE SPREAD IN SOLUTIONS, AN
ISOTHERMALLY RESEMBLANT PICTURE WITHIN THE DGZ COMPOUNDS HEAVY
SNOW CONCERNS. WHILE HIGH RESOLUTION MODEL ANALYSIS REMAINS
LIMITED AT THE CURRENT FORECAST HOUR (48), ALL SHOW A NARROW
BAND OF 2500M DGZ THICKNESS JUST NORTH OF THE FORECAST AREA AT
28.06Z, BEFORE SNOWFALL PROBABILITIES INCREASE LOCALLY.
ULTIMATELY, COLLOCATION WITH ENHANCED FRONTOGENESIS WILL BE THE
MAIN FORECAST DETAIL TO REMAIN COGNIZANT OF REGARDLESS OF
LOCATION OF THIS VERY THICK DGZ FILAMENT.
WARMING THROUGH NEXT WEEK:
WHILE CURRENT FORECAST CONFIDENCE CALLS FOR MORE SEASONABLE
TEMPERATURES THROUGH THE START OF THE NEW WEEK GRADUALLY WARMING
DUE TO STRENGTHENING OF SOUTHEASTERN US ANTICYCLONIC FLOW, A
PLUME OF COLDER TEMPERATURES ESTRANGED FROM THE EARLY WEEKEND
TROUGH IN THE EPS LINGERS POTENTIALLY COOLER TEMPERATURES
THROUGH EARLY NEXT WEEK. EVENTUALLY, DO EXPECT WARMER THAN
NORMAL TEMPERATURES LATER IN THE FORECAST PERIOD INTO MID NEXT
WEEK.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1104 AM CST THU FEB 26 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH MOSTLY CLEAR
SKIES OUTSIDE OF FEW TO SCT HIGH CLOUDS. CHANGING WIND DIRECTION AND
SPEED IS THE PRIMARY DRIVER OF THE TAFS FOR THE NEXT 24 HOURS AS
WINDS WILL DECREASE SLIGHTLY TONIGHT, BUT WILL THEN INCREASE TOWARDS
18Z ON FRIDAY AS DIURNAL MIXING WILL ALLOW FOR SOME STRONGER GUSTS
TO GET TO THE SURFACE DURING THE AFTERNOON, PRIMARILY WEST OF THE
MISSISSIPPI RIVER. WITH A STRENGTHEN LOW-LEVEL JET ATOP THE
NOCTURNAL INVERSION TO 45 KTS OR SO IN THE RAP/HRRR, MAY SEE SOME
LLWS DURING THE MORNING HOURS ACROSS THE REGION, PARTICULARLY IN
MORE SHELTERED AREAS SUCH AS KLSE.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...NAYLOR
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