391
FXUS63 KLOT 221106
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
506 AM CST SAT FEB 22 2025
KEY MESSAGES
- WARMING TREND INTO THE MIDDLE OF NEXT WEEK. HIGHS IN THE 40S
AND 50S MONDAY AND TUESDAY, AND POSSIBLY INTO WEDNESDAY.
- CHANCES FOR RAIN/SHOWERS MONDAY NIGHT (20-30%) AND WEDNESDAY
INTO WEDNESDAY NIGHT (30-50%)
DISCUSSION
ISSUED AT 210 AM CST SAT FEB 22 2025
THROUGH SUNDAY:
TWO MID TO UPPER-LEVEL WAVES WILL BOOKEND THE FORECAST AREA
TODAY, FILTERING SOME UPPER-LEVEL CLOUDS TO THE NORTH AND SOUTH.
INCREASING SOUTHWEST WINDS BETWEEN A LOW OVER NORTHERN ONTARIO
AND A PERSISTENT RIDGE ALIGNED WITH THE OHIO RIVER VALLEY WILL
RESULT IN GUSTS TO AROUND 25 MPH LATE THIS MORNING INTO THE
AFTERNOON. TEMPS WILL CONTINUE TO MODERATE, WITH LOW/NO-SNOWPACK
AREAS LIKELY SURPASSING THE FREEZING MARK THIS AFTERNOON.
UPPER-LEVEL CLOUDS WILL THICKEN ACROSS THE AREA OVERNIGHT INTO
SUNDAY MORNING AS AN UPPER-LEVEL WAVE SHIFTS ESE. A DECENT
AMOUNT OF VIRGA WILL GRADUALLY SATURATE CLOUD BASES DOWN TO
AROUND 10KFT OR LOWER BY AROUND SUNRISE. WOULD NOT BE ENTIRELY
SURPRISED TO SEE SOME FLURRIES REACH THE GROUND FOR A FEW HOURS
THROUGH MID-MORNING ACROSS NORTHERN ILLINOIS AND ESPECIALLY
CLOSER TO THE WISCONSIN LINE. OTHERWISE, TEMPS WILL AGAIN SLOWLY
MODERATE WITH HIGHS RANGING FROM THE MID 30S NORTH TO LOW TO
MID 40S SOUTH.
KLUBER
SUNDAY NIGHT THROUGH FRIDAY:
A SERIES OF UPPER-LEVEL WAVES WILL SCOOT ACROSS THE REGION NEXT
WEEK, DELIVERING AT LEAST SOME INTERMITTENT PRECIPITATION
CHANCES ALONG WITH NOTABLY MILDER CONDITIONS.
THE FIRST FEATURE WILL ARRIVE SUNDAY EVENING AND OVERNIGHT ON
THE NOSE OF A 180 KNOT JET STREAK, ALTHOUGH THE MAIN VORT MAX
WILL REMAIN WELL TO OUR NORTH. WITH ATTENDANT HEIGHT FALLS
FOCUSED PRIMARILY ACROSS WISCONSIN AND MICHIGAN, ANY
PRECIPITATION OF CONSEQUENCE WITHIN THE SYSTEM'S BROAD N-S WARM
ADVECTION WING LOOKS TO REMAIN NORTH AND EAST OF THE FORECAST
AREA. SUPPOSE WE CAN'T ENTIRELY RULE OUT A FEW SPRINKLES (OR
EVEN AN ICE PELLET GIVEN SUB-CLOUD DRY AIR WITH WETBULB
TEMPERATURES NEAR FREEZING) ACROSS PARTS OF NE ILLINOIS, BUT
CHANCES ARE UNDER 10 PERCENT. WE'LL BE BETWEEN SYSTEMS MONDAY
AFTERNOON, AND WHILE HIGH-LEVEL CLOUD COVER LOOKS SET TO
INCREASE FAIRLY QUICKLY BY LATE IN THE DAY, THE COMBINATION OF
BREEZY SOUTHWESTERLY WINDS AND 925 MB TEMPERATURES IN THE +3 TO
+7 C RANGE SHOULD HELP BOOST HIGHS INTO THE 40S AND 50S, WARMEST
SOUTH OF I-80 WHERE THE SNOWPACK IS ESSENTIALLY NON-EXISTENT.
THE NEXT DISTURBANCE IN THE WAVE TRAIN WILL PUSH THROUGH MONDAY
EVENING AND OVERNIGHT. THERE'S BEEN A LOT OF NORTH-SOUTH
WOBBLING ACROSS THE GUIDANCE SUITE WITH THIS FEATURE, ALTHOUGH
A RELATIVELY MORE STEADY STATE SOLUTION ADVERTISED BY THE ECMWF
OFFERS UP A MORE AMPLIFIED AND FARTHER SOUTH SOLUTION. THIS
WOULD BRING INCREASED FORCING FOR ASCENT AND BETTER
PRECIPITATION CHANCES INTO THE LOCAL AREA COMPARED TO THE
FARTHER NORTH GFS/GEFS OUTPUT. BLENDED POPS STILL LOOK OKAY FOR
THIS TIME RANGE, IN THE LOW-MID CHANCE RANGE MONDAY
EVENING/EARLY OVERNIGHT GIVEN THE SPREAD IN MODEL GUIDANCE.
THERMAL PROFILES LOOK JUST WARM ENOUGH TO KEEP EVERYTHING AS
RAIN.
CONDITIONS LOOK TO CLEAR OUT NICELY THROUGH TUESDAY MORNING AND
AFTERNOON AS A SURFACE RIDGE AXIS VERY BRIEFLY BUILDS BACK
ACROSS THE REGION. HIGH TEMPERATURES SHOULD BE SIMILAR, OR EVEN
A SMIDGE WARMER THAN ON MONDAY.
ON WEDNESDAY, A POSITIVE-TILT SHORTWAVE NESTLED WITHIN A BROADER
LONGWAVE TROUGH IS SLATED TO SHIFT ACROSS THE MIDWEST AND GREAT
LAKES. MID-UPPER LEVEL TEMPERATURES ARE FORECAST TO APPROACH -30
C WHICH WILL SUPPORT FAIRLY STEEP 700-500 MB LAPSE RATES AHEAD
OF THE MAIN VORT LOBE INTO WEDNESDAY MORNING AND AFTERNOON. AS A
RESULT, IT'S NOT SURPRISING THAT PRECIPITATION LOOKS DECIDEDLY
MORE SHOWERY AND CONVECTIVE WITH THIS WAVE. STILL NOT SUPER
CONFIDENT ON THE PRECISE SYSTEM TRACK AND PLACEMENT OF HIGHEST
PRECIPITATION CHANCES, BUT THERE IS A BETTER SIGNAL IN ENSEMBLE
GUIDANCE FOR AT LEAST LIGHT QPF ACROSS THE REGION COMPARED TO
THE MONDAY NIGHT WAVE. WHILE TEMPERATURES WILL BE A BIT COOLER,
THERMAL PROFILES STILL LOOK TO SUPPORT LARGELY NON-FROZEN
PRECIPITATION. IF CONVECTIVE PROCESSES END UP DOMINATING, THE
COLUMN COULD COOL SUFFICIENTLY TO FLIP THINGS A BIT MORE TOWARDS
SNOW (OR EVEN A LITTLE SLEET IF UPRIGHT CONVECTION IS
REALIZED), BUT THERE'S STILL WAY TOO MUCH UNCERTAINTY AT THIS
POINT TO GET THAT FINE IN THE GRIDDED FORECAST.
THE PATTERN UPSTAIRS WILL REMAIN EXCEEDINGLY ACTIVE THROUGH THE
REST OF THE WEEK AND INTO THE WEEKEND WITH SEVERAL ADDITIONAL
CHANCES FOR PRECIP ALTHOUGH NOTHING THAT CURRENTLY LOOKS OVERLY
IMPACTFUL AT THIS POINT.
CARLAW
AVIATION /12Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 506 AM CST SAT FEB 22 2025
THERE ARE NO SIGNIFICANT AVIATION WEATHER CONCERNS. SOUTHWEST
WINDS WILL INCREASE THIS MORNING, WITH GUSTS INTO THE 20-25 KT
RANGE EXPECTED INTO THE AFTERNOON BEFORE EASING AROUND OR
SHORTLY AFTER SUNSET. OCCASIONAL UPPER TO MID-LEVEL CLOUD DECKS
WILL STREAM OVERHEAD, WITH CLOUDS EXPECTED TO THICKEN LATE
TONIGHT INTO SUNDAY MORNING.
CARLAW
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR WINTHROP HARBOR TO WILMETTE HARBOR IL.
VISIT US AT WEATHER.GOV/CHICAGO
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