952
FXUS63 KLOT 092325
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
525 PM CST MON FEB 9 2026
KEY MESSAGES
- MILDER TEMPERATURES ARE EXPECTED FOR MUCH OF THE WEEK.
DISCUSSION
ISSUED AT 138 PM CST MON FEB 9 2026
A LOW-AMPLITUDE MID-LEVEL WAVE NEAR YELLOWSTONE WILL QUICKLY
TRACK EASTWARD THROUGH TONIGHT, CROSSING NORTHERN WISCONSIN LATE
TONIGHT. AHEAD OF THE WAVE LATE THIS AFTERNOON AND EVENING,
SUBSTANTIAL LOWER TROPOSPHERIC WAA/ISENTROPIC ASCENT WILL
ENCOUNTER A RATHER DRY AIRMASS, WITH THE ONLY NOTABLE EFFECTS ON
SENSIBLE WEATHER LIMITED TO PLENTY OF MID/UPPER-LEVEL CLOUDS,
STEADY OR GRADUALLY WARMING OVERNIGHT TEMPS, AND PERHAPS
SPORADIC GUSTS THROUGH THE NIGHT. THE ASSOCIATED COLD FRONT WILL
CROSS THE AREA IN THE PRE-DAWN HOURS THROUGH AROUND SUNRISE,
WITH GUSTY WINDS IN STORE FOR MUCH OF THE DAY ON TUESDAY. WITH A
SHARPENING LOW-LEVEL PRESSURE GRADIENT FROM A SECONDARY WAVE
CROSSING THE NORTHERN GREAT LAKES AND A MODESTLY FAVORABLE
ISALLOBARIC WIND COMPONENT, NW WINDS MAY SPORADICALLY GUST TO 30
TO 35 MPH DURING THE AFTERNOON.
A BROAD AND WEAKENING RIDGE OVER THE NORTHERN GREAT PLAINS ON
WEDNESDAY WILL SHIFT ACROSS THE WESTERN GREAT LAKES ON THURSDAY
BEFORE ANOTHER QUICK-MOVING WAVE TRAVERSES THE AREA LATE
THURSDAY INTO THURSDAY NIGHT. PERSISTENT LOW TO MID-LEVEL
ISENTROPIC ASCENT BELOW A SOMEWHAT STATIONARY RIGHT ENTRANCE
REGION OF THE UPPER-LEVEL JET WILL ALLOW FOR GRADUAL TOP-DOWN
SATURATION WEST OF THE AREA THROUGHOUT THE DAY THURSDAY. IT
REMAINS TO BE SEEN THOUGH IF THERE WILL BE ENOUGH SATURATION TO
THE SURFACE THIS FAR EAST BY THURSDAY EVENING AS SUPPORT FROM
THE UPPER-JET WILL BEGIN SHIFTING EAST OF THE AREA. WILL
MAINTAIN OVERALL LOW-END CHANCE POPS FOR LOW QPF AS SNOW ACROSS
MOST OF THE AREA THURSDAY AFTERNOON AND EVENING. ANY PRECIP
SHOULD END BY DAYBREAK FRIDAY WITH WEAK RIDGING SHIFTING ACROSS
THE AREA THROUGH THE DAY.
FOCUS THEN TURNS TO A SLOW-MOVING SUB-TROPICAL TROUGH OVER THE
BAJA OF CALIFORNIA LATE THIS WEEK AND ITS INTERACTION WITH, OR
LACK THEREOF, A FASTER CLUSTER OF DISTURBANCES TRACKING FROM THE
PACIFIC NORTHWEST AND BRITISH COLUMBIA TOWARD THE FAR NORTHERN
GREAT LAKES LATE SATURDAY INTO SUNDAY. ENSEMBLE AND ESPECIALLY
DETERMINISTIC GUIDANCE CONTINUES TO STRUGGLE WITH THE AMOUNT OF
THE NORTHWARD EXTENT OF PRECIP WITH THE STRONGER SOUTHERN WAVE,
PRIMARILY OWING TO THE HOW MUCH ENERGY WILL BE DRAWN INTO THE
NORTHERN WAVE. WHILE THERE HAS BEEN A SOUTHWARD TREND IN THE
PRECIP SHIELD OVER THE PAST SEVERAL ENSEMBLE CYCLES, WE ARE
STILL FIVE DAYS OR MORE OUT AND WILL NEED TO CONTINUE TO MONITOR
FUTURE TRENDS IN THE TRACK OF BOTH WAVES OVER THE COMING DAYS.
IN THE EVENT PRECIP DOES EXPAND WELL NORTH INTO THE AREA,
ACCUMULATING SNOW WILL BE IN PLAY LATE SATURDAY INTO EARLY
SUNDAY.
KLUBER
AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 525 PM CST MON FEB 9 2026
KEY MESSAGES:
- LLWS DEVELOPING AT 04Z THIS EVENING AND CONTINUING OVERNIGHT.
- SOUTH-SOUTHWESTERLY WINDS TURN NORTHWEST AROUND DAYBREAK
TUESDAY, THEN TURN GUSTY BY MIDDAY.
VFR CONDITIONS ARE ANTICIPATED THROUGH THE TAF PERIOD, WITH ONLY
SOME HIGHER LEVEL CIGS EXPECTED. SOUTH WINDS EARLY THIS EVENING
WILL TURN SOUTHWEST OVERNIGHT. WHILE SURFACE WIND SPEEDS WILL
REMAIN IN CHECK (10-15 KT), SOUTHWEST WINDS WILL INCREASE UP TO
50 KT A COUPLE THOUSAND FEET OFF THE SURFACE LATER THIS EVENING
AND OVERNIGHT. ACCORDINGLY, LLWS IS EXPECTED FOR SEVERAL HOURS
TONIGHT. THE ONLY CHANGE WITH THIS FORECAST IN THE TAFS WAS TO
INCREASE THE SPEED IN THE LLWS FROM 45 TO 50 KT. OTHERWISE,
EXPECT A COLD FRONT TO SWEEP ACROSS THE AREA AROUND, OR JUST
AFTER, DAYBREAK TUESDAY MORNING. IN ITS WAKE, SURFACE WINDS
WILL TURN NORTHWESTERLY, WITH GUSTINESS INCREASING (~25 KT)
LATER IN THE MORNING AND AFTERNOON BEFORE ABATING WITH SUNSET
EARLY TUESDAY EVENING.
KJB
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM CST TUESDAY FOR
WINTHROP HARBOR IL TO GARY IN.
VISIT US AT WEATHER.GOV/CHICAGO
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