054
FXUS63 KLOT 260839
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
239 AM CST THU FEB 26 2026
KEY MESSAGES
- QUICK WARM-UP FOR THE END OF THE WEEK, WITH DRY, WINDY AND
VERY MILD WEATHER EXPECTED FRIDAY. THESE CONDITIONS MAY RESULT
IN A HEIGHTENED GRASS/BRUSH FIRE DANGER FRIDAY AFTERNOON.
- COLDER WITH SOME ADDITIONAL SNOW CHANCES OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 239 AM CST THU FEB 26 2026
THROUGH FRIDAY NIGHT...
MAIN WEATHER CONCERNS THROUGH THE PERIOD INCLUDE SNOW ENDING
PREDAWN ACROSS OUR FAR SOUTHERN CWA, THEN A DRY, WINDY AND MUCH
WARMER DAY ON FRIDAY. WARMTH, WINDS AND LOW HUMIDITY FRIDAY WILL
LIKELY LEAD TO ANOTHER HEIGHTENED GRASS/BRUSH FIRE SPREAD
POTENTIAL.
REGIONAL RADAR IMAGERY INDICATES AN AREA OF SNOW EXITING OUR
FAR SOUTHERN TIER OF COUNTIES, AFTER PRODUCING A QUICK PERIOD OF
MODERATE SNOW WITH SOME MINOR ACCUMULATIONS NOTED ON ROADWAYS
PER WEBCAMS ALONG OUR BORDER WITH ILX. SNOW WILL CONTINUE TO
SHIFT OFF TO THE SOUTHEAST PRIOR TO SUNRISE, IN ASSOCIATION WITH
A MID-LEVEL SHORT WAVE TRACKING SOUTHEAST INTO THE LOWER OHIO
VALLEY. CLOUD COVER LINGERS TO THE WEST/NORTHWEST OF THE
DEPARTING WAVE AS FAR BACK AS IA/SOUTHERN MN, AND WILL LINGER
ACROSS THE REGION THIS MORNING BEFORE DECREASING
MIDDAY/AFTERNOON AS STRONGER DEEP-LAYER SUBSIDENCE DEVELOPS. AT
THE SURFACE, WEAK HIGH PRESSURE CENTERED OVER SOUTHERN LAKE
MICHIGAN/SOUTHWEST LOWER MICHIGAN WILL DRIFT EAST THIS MORNING,
ALLOWING WINDS TO TURN SOUTHWEST THIS AFTERNOON. SPEEDS WILL BE
MODEST, THOUGH SOME GUSTS INTO THE 15-20 MPH RANGE APPEAR
POSSIBLE ACROSS NORTHWEST IL, WHERE THE GRADIENT WILL TIGHTEN
JUST A BIT. WARM ADVECTION DEVELOPING ALOFT, COMBINED WITH THE
MODEST SOUTHWEST WINDS AND SOME SUNSHINE THIS AFTERNOON SHOULD
ALLOW TEMPERATURES TO RECOVER INTO THE LOW-MID 40S ACROSS MUCH
OF THE FORECAST AREA.
TONIGHT, A POTENT MID-LEVEL SHORT WAVE IS PROGGED TO DIG
SOUTHEAST ACROSS THE CANADIAN PRAIRIE PROVINCES, WITH A
DEEPENING SURFACE LOW DEVELOPING TO THE MANITOBA/ONTARIO BORDER
REGION EAST OF LAKE WINNIPEG BY MORNING. A BROAD AREA OF SURFACE
PRESSURE FALLS IS FORECAST SOUTHEAST OF THE ~990 MB LOW,
EXTENDING ACROSS THE UPPER MIDWEST AND INCREASING WARM ADVECTION
ALOFT ON A WESTERLY 25-30 KT LOW-LEVEL JET. MOSTLY CLEAR SKIES
SHOULD ALLOW FOR WINDS TO DECOUPLE ACROSS OUR AREA DURING THE
EVENING, WITH TEMPERATURES FALLING INTO THE UPPER 20S/LOWER 30S
OVERNIGHT WITH LIGHT SOUTHWEST WINDS.
THE STOUT WAVE TO OUR NORTH IS EXPECTED TO CONTINUE TO AMPLIFY
ACROSS THE NORTHERN GREAT LAKES ON FRIDAY. WHILE THE SURFACE LOW
PASSES NORTH OF LAKE SUPERIOR, ASSOCIATED SURFACE
PRESSURE/HEIGHT FALLS ARE FORECAST TO FURTHER STRENGTHEN THE
WEST-SOUTHWEST LOW LEVEL JET INTO THE 40-50 KT RANGE. FORECAST
SOUNDINGS VARY WITH THEIR MIXING DEPTH DURING THE
MIDDAY/AFTERNOON HOURS, THOUGH IT LOOKS LIKE WE'D LIKELY BE ABLE
TO MIX DOWN 30-35 MPH GUSTS - AND POTENTIALLY STRONGER GUSTS IF
WE MIX MORE DEEPLY. TEMPERATURES ARE EXPECTED TO EASILY REACH
THE LOW-MID 60S DURING THE AFTERNOON, AND POTENTIALLY NEAR 70
ALONG WITH LOWER SURFACE DEW POINTS IF DEEPER MIXING OCCURS.
HAVE BOOSTED SURFACE WINDS/GUSTS AND LOWERED SURFACE DEW POINTS
FROM NBM DELIVERED GUIDANCE, AND WILL HAVE TO MONITOR TRENDS FOR
A FURTHER HEIGHTENED GRASS/BRUSH FIRE SPREAD POTENTIAL. SEE
FIRE WEATHER SECTION OF THIS DISCUSSION BELOW.
AS THE SURFACE LOW MOVES FURTHER EAST ACROSS ONTARIO LATE
FRIDAY, A TRAILING COLD FRONT WILL MOVE INTO NORTHERN IL LATE,
AND WILL PUSH SOUTHEAST ACROSS THE AREA FRIDAY EVENING/NIGHT.
WINDS WILL EASE AND SHIFT NORTHWEST, THOUGH WILL LIKELY REMAIN
SOMEWHAT BLUSTERY OVERNIGHT IN THE LOW-LEVEL COLD ADVECTION
REGIME. TEMPERATURES THUS WILL FALL INTO THE 30S/40S WITH WIND
CHILLS DIPPING INTO THE 20S BY MIDNIGHT AFTER 60-DEGREE WARMTH
FRIDAY AFTERNOON.
RATZER
SATURDAY THROUGH THURSDAY...
TOWARD THE END OF THE WEEK, MODEL GUIDANCE IS IN AGREEMENT ON A
SHORTWAVE CLIPPER DISTURBANCE ROUNDING THE BASE OF THE BROAD
UPPER TROUGH AS IT TRANSECTS THE NORTHERN CONUS. THIS FEATURE
WILL STEER DIRECTLY INTO NORTHERN IL EARLY SATURDAY BRINGING A
CLIP OF ACCUMULATING SNOW SHOWERS NEARBY. ALL DETERMINISTIC
CAMPS, WITH THE EXCEPTION OF THE GFS, NOW TRACK THE PRIMARY AXIS
OF SNOWFALL, WITH ACCUMULATIONS BETWEEN ONE AND TWO INCHES,
JUST TO OUR NORTH ACROSS SOUTHERN WI WITH GENERALLY LESS THAN
INCH FAVORED SOUTH OF THE STATE LINE. SOME EVEN SUGGEST THAT
ANTECEDENT LOW LEVEL DRY AIR MAY BE TOO MUCH TO SUPPORT MUCH
PRECIP DEVELOPMENT ACROSS A BIG MAJORITY OF OUR CWA. THERE'S
PLENTY OF SUPPORT THOUGH FOR AT LEAST LIGHT SNOW SHOWERS AND
FLURRIES AROUND MOST OF THE AREA, BUT CHANCES DO GENERALLY LOOK
WORSE WITH SOUTHWARD EXTENT. IF PRECIP FALLS IN OUR SOUTHERN
CWA, IT'S COULD BE IN FORM OF RAIN OR A WINTRY MIX. TIME WINDOW
FOR SNOW ON SATURDAY IS ROUGHLY MID-MORNING INTO THE EARLY
EVENING.
STILL LOOKING LIKE A POTENTIALLY ACTIVE STRETCH OF WEATHER
AROUND THE REGION NEXT WEEK, STARTING WITH A SYSTEM IN THE
SUNDAY-SUNDAY NIGHT WINDOW WHICH SHOWS POTENTIAL TO BRING
NOTEWORTHY WINTRY IMPACTS TO PARTS OF THE REGION. GUIDANCE HAS
COME INTO BETTER AGREEMENT RECENTLY WITH WHERE TO TRACK THE
STORM AND THE CORRIDOR OF HIGHEST SNOW TOTALS, BUT THERE'S STILL
MUCH TO BE IRONED OUT. FOR SEVERAL RUNS, THE GFS HAD PREVIOUSLY
BEEN WANTING TO STEER A WIDESPREAD SEVERAL INCHES OF SNOWFALL
ACROSS NORTHERN IL. WELL OVER THE LAST 24 HOURS, THE GFS AND ITS
ENSEMBLE COUNTERPART HAVE BEEN ON A BIG SOUTHWARD TREND AND NOW
EVEN TRACK THE STORM FARTHER SOUTH THAN MOST OTHER AVAILABLE
GUIDANCE. THE DETERMINISTIC EURO HAS BEEN, AND CONTINUES TO BE,
REMARKABLY CONSISTENT ALTHOUGH THE ENS ISN'T NEARLY AS SURE. ALL
LATEST DETERMINISTIC CAMPS NOW BRING THE HIGHEST SNOW TOTALS
ACROSS CENTRAL IL, AND SOME ROPE SOUTHERN PORTIONS OF OUR CWA
INTO THAT CORRIDOR. BUT THERE REMAINS QUITE A LOT OF SPREAD
AMONG ENSEMBLE MEMBERS INCLUDING A NOTABLE AMOUNT OF SUPPORT
STILL FOR THE MAIN AXIS OF SNOW TO TRACK ACROSS NORTHERN IL. IT
DOES APPEAR THOUGH THAT THE TREND IS FOR CENTRAL IL TO BE THE
MOST IMPACTED FROM THIS SYSTEM. A FEW TO SEVERAL INCHES OF
ACCUMULATION ARE FAVORED IN THE MAIN CORRIDOR OF SNOWFALL. IT'S
TOUGH TO SAY THE NORTHERN EXTENT OF SNOW COVERAGE WITH SOME DRY
LAYER AIR STILL INFILTRATING FROM THE EAST DIVERGING FROM A
GREAT LAKES HIGH. SNOW SHOWERS SUNDAY TO SUNDAY NIGHT WILL BE
POSSIBLE AREA-WIDE, BUT TOO EARLY TO GET SPECIFIC ON IMPACTS FOR
ANY GIVEN AREA.
A TIGHT BAROCLINIC ZONE WILL GET LOCKED UP ACROSS THE MIDWEST
NEXT WEEK AND STEER A NUMBER OF WAVES NEARBY, SO WE'LL SEE AT
LEAST A COUPLE OF MORE OPPORTUNITIES FOR RAIN AND SNOW NEXT
WEEK. EXPECTING SEASONABLY COOL CONDITIONS THROUGH EARLY NEXT
WEEK, BUT GUIDANCE STRONGLY FAVORS A WARMING TREND FOR MID-LATE
WEEK.
DOOM
AVIATION /06Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 1045 PM CST WED FEB 25 2026
THERE ARE NO FORECAST CONCERNS THIS PERIOD. LIGHT NORTHWEST
WINDS WILL BECOME VARIABLE OR CALM OVERNIGHT THEN BECOME
SOUTH/SOUTHWEST THURSDAY MORNING, INCREASING TO 10-12KT IN THE
AFTERNOON WITH SOME HIGHER GUSTS POSSIBLE. LOW LEVEL WINDS WILL
INCREASE THURSDAY EVENING AND WILL NEED TO BE MONITORED FOR
POSSIBLE LOW LEVEL WIND SHEAR. CMS
FIRE WEATHER
ISSUED AT 239 AM CST THU FEB 26 2026
A HEIGHTENED GRASS/BRUSH FIRE SPREAD THREAT EXISTS FOR FRIDAY.
MUCH OF THE AREA HAS BEEN QUITE DRY OVER THE PAST SEVERAL
WEEKS, WITH NO SIGNIFICANT SNOW COVER, ALLOWING FUELS TO BE
RELATIVELY DRY.
STRONG, GUSTY SOUTHWEST WINDS ARE EXPECTED TO DEVELOP FRIDAY IN
RESPONSE TO A DEEP LOW PRESSURE SYSTEM MOVING NORTH OF THE
GREAT LAKES. STRONG WARM ADVECTION IS EXPECTED PRODUCE
TEMPERATURES IN THE LOW-MID 60S ACROSS THE AREA, WITH WINDS 15
TO 20 MPH GUSTING UP TO 35 MPH DURING THE MIDDAY AND AFTERNOON
HOURS. AFTERNOON MINIMUM RELATIVE HUMIDITY LEVELS ARE CURRENTLY
FORECAST TO DIP INTO THE 30- 35 PERCENT RANGE. HOWEVER, IF
DEEPER DAYTIME MIXING WERE TO OCCUR, IT WOULD POTENTIALLY
SUPPORT WARMER TEMPERATURES, LOWER HUMIDITY LEVELS (LESS THAN
30%) AND STRONGER WIND GUSTS. THIS WOULD SUPPORT CONDITIONS
POTENTIALLY DROPPING BELOW CRITICAL RED FLAG THRESHOLDS.
WE'LL CONTINUE TO MONITOR THESE TRENDS WITH FORECAST UPDATES
LATER TODAY, AND CONTINUE TO ASSESS THE POTENTIAL NEED FOR ANY
FIRE WEATHER HEADLINES.
RATZER
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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