271
FXUS63 KLOT 281749
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
1249 PM CDT FRI MAR 28 2025
KEY MESSAGES
- SPOTTY SHOWERS AND STORMS MAY LINGER THROUGH THE MORNING. MOST
AREAS WILL REMAIN DRY.
- WINDY AND WARM WITH SOUTHWEST WINDS GUSTING TO 40 MPH THIS
AFTERNOON.
- A COLD FRONT WILL MOVE SOUTH INTO NORTHERN IL SATURDAY
AFTERNOON, TURNING TEMPS MUCH COOLER, ESPECIALLY NEAR LAKE
MICHIGAN.
- SCATTERED SHOWERS, POSSIBLE THUNDERSTORMS SATURDAY/SATURDAY
NIGHT, AS THE COLD FRONT LIFTS BACK NORTH AS A WARM FRONT.
- SEVERE THUNDERSTORMS ARE POSSIBLE ON SUNDAY, WITH POTENTIAL
HAZARDS INCLUDING DAMAGING WIND, HAIL, AND TORNADOES.
DISCUSSION
ISSUED AT 240 AM CDT FRI MAR 28 2025
THROUGH SATURDAY:
SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP AND MOVE EAST ACROSS
THE AREA EARLY THIS MORNING AND WILL CONTINUE THROUGH MID
MORNING, SLOWLY ENDING FROM WEST TO EAST. THE STRONGEST STORMS
WILL HAVE THE POTENTIAL TO PRODUCE HAIL TO NICKEL SIZE AS WELL
AS BRIEF HEAVY RAIN. WHILE THE BULK OF THIS ACTIVITY LOOKS TO BE
EXITING THE CWA BY MID MORNING (13Z-14Z), SOME OF THE CAMS ARE
SHOWING AN AXIS OF INSTABILITY LINGERING ALONG THE I-80 CORRIDOR
WHERE A FEW SHOWERS OR A FEW THUNDERSTORMS MAY LINGER THROUGH
EARLY AFTERNOON. CONFIDENCE IS LOW, BUT MAINTAINED SLIGHT CHANCE
POPS THROUGH 18Z. ONCE THIS POTENTIAL ENDS, DRY WEATHER IS
EXPECTED THROUGH SATURDAY MORNING.
WINDS WILL BECOME SOUTHWESTERLY AFTER SUNRISE AND STEADILY
INCREASE THROUGH THE MORNING. THE STRONGEST WINDS ARE EXPECTED
THIS AFTERNOON ONCE THE CLOUDS CLEAR AND THE LOW LEVELS BEGIN TO
MIX DEEPLY. GUSTS INTO THE 40 MPH RANGE ARE EXPECTED FROM MID
AFTERNOON THROUGH SUNSET AND ITS POSSIBLE SOME GUSTS WILL REACH
45 MPH. THESE MAY BE BRIEF AND ISOLATED AND THUS NOT PLANNING
ANY WIND ADVISORY, BUT TRENDS WILL NEED TO BE MONITORED INTO
THIS AFTERNOON. SPEEDS AND GUSTS WILL DIMINISH SOME WITH SUNSET,
BUT GUSTS INTO THE 30-35 MPH ARE STILL EXPECTED THIS EVENING,
ESPECIALLY IN THE METRO AREA, DIMINISHING FURTHER OVERNIGHT
INTO SATURDAY MORNING.
WITH THE EXPECTATION THAT SKIES WILL BECOME MOSTLY SUNNY THIS
AFTERNOON, TEMPERATURES ARE EXPECTED TO EASILY RISE INTO THE
MID/UPPER 70S ACROSS THE ENTIRE AREA. TEMPS OFTEN OVERPERFORM IN
THESE SITUATIONS, THUS A FEW LOCATIONS TAGGING 80 IS CERTAINLY
POSSIBLE. LOW TEMPS WILL LIKELY ONLY DROP INTO THE MID/UPPER 50S
TONIGHT.
SOUTHWEST WINDS WILL BE GUSTING INTO THE 30 MPH RANGE AS TEMPS
WARM INTO THE MID/UPPER 60S SATURDAY. A COLD FRONT WILL BE
MOVING SOUTH ACROSS WI AND WILL LIKELY SURGE SOUTH DOWN LAKE
MICHIGAN IN THE AFTERNOON, STALLING ON THE SOUTH END OF THE
LAKE BY EVENING. THIS WILL TURN TEMPS MUCH COLDER NORTH OF THIS
FRONT AND ESPECIALLY NEAR THE LAKE. THERE WILL BE A LARGE
TEMPERATURE DIFFERENCE BETWEEN THIS FRONT THOUGH HIGHS INTO THE
LOWER 70S ARE POSSIBLE ACROSS THE SOUTHERN CWA SATURDAY
AFTERNOON.
PRECIP TRENDS ARE UNCERTAIN FOR SATURDAY. THERE MAY BE SOME
SHOWERS, ISOLATED THUNDER ACROSS THE SOUTHERN CWA SATURDAY
MORNING WITH MANY DRY HOURS EXPECTED ACROSS THE ENTIRE AREA,
THEN A CHANCE OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS BY
LATE SATURDAY AFTERNOON. OVERALL CONFIDENCE IS LOW AND CURRENT
POPS IN THE 40-50% RANGE FOR SATURDAY AFTERNOON MAY BE TOO HIGH,
BUT NO CHANGES PLANNED. CMS
SATURDAY NIGHT THROUGH THURSDAY:
FOCUS THEN TURNS TO THE POTENTIAL FOR SEVERE WEATHER OVER AT
LEAST PART OF THE FORECAST AREA ON SUNDAY. VEERING LOW-LEVEL
FLOW WITH ONLY SPOTTY UPSTREAM PRECIP SATURDAY NIGHT SHOULD
ALLOW THE FRONT TO RETREAT NORTHWARD AS A WARM FRONT. A LARGER
SURFACE LOW WILL THEN TRAVERSE ALONG OR NEAR THE WARM FRONT
SOMEWHERE ACROSS NORTHERN ILLINOIS ON SUNDAY. LIKE ON SATURDAY,
THE GEFS HAS TRENDED MUCH FARTHER NORTH WITH THE WARM FRONT,
WITH MUCH OF THE GUIDANCE NOW PUTTING AT LEAST THE SOUTHERN HALF
OF THE CWA IN THE WARM SECTOR. IMPRESSIVE MID TO UPPER-LEVEL
DYNAMICS, SPECIFICALLY WITH AN INCOMING 70 KNOT MID-LEVEL JET
STREAK, OVER MODEST LOW-LEVEL MOISTURE ADVECTION WILL SUPPORT A
SEVERE STORM RISK, PARTICULARLY SOUTH OF I-80, AND POTENTIALLY
FARTHER NORTH AND WEST DEPENDING ON IF/WHERE THE WARM FRONT
STALLS DUE TO THE INFLUENCE OF LAKE MICHIGAN. SHEAR VECTORS AND
SOMEWHAT UNIDIRECTIONAL LOW-LEVEL FLOW FAVOR LINEAR/BOWING
CONVECTIVE SEGMENTS WITH WIND DAMAGE AS THE PRIMARY THREAT
(LARGE HAIL WITH ANY MORE DISCRETE CELLS). BUT AGAIN
CLIMATOLOGICALLY SPEAKING, BOTH THE STORM MODE (BROKEN/BOWING
SEGMENTS) IN THIS AREA AND THE POTENTIAL FOR A STALLED WARM
FRONT DOES SUPPORT A LOW END TORNADO RISK (PARTICULARLY QLCS).
STILL A FEW DAYS OUT TO REFINE THESE DETAILS, WITH FRONTAL
LOCATION BEING A SIGNIFICANT FACTOR WITH HOW THE FORECAST
EVOLVES THIS WEEKEND. THE STORM PREDICTION CENTER INTRODUCED A
LEVEL 3 OUT OF 5 RISK ACROSS PARTS OF THE AREA SOUTH OF I-80,
WHICH SEEMS APPROPRIATE GIVEN THE NORTHWARD SHIFT IN GUIDANCE
WITH THE WARM SECTOR. STAY TUNED FOR FORECAST UPDATES!
AS THE MAIN TROUGH AXIS CROSSES THE FORECAST AREA SUNDAY NIGHT,
A RESIDUAL BAND OF RAIN SHOULD MIX WITH OR EVEN TRANSITION TO
SNOW. THERE IS A LOW (10%) CHANCE OF SOME MINOR SLUSHY
ACCUMULATIONS LATE SUNDAY NIGHT INTO MONDAY MORNING, BUT OVERALL
EXPECTATIONS ARE FOR LITTLE IMPACT AT THIS TIME. DRIER AND
COLDER CONDITIONS WILL FOLLOW THROUGH TUESDAY WITH HIGHS
GENERALLY IN THE 40S. LONG-TERM ENSEMBLE GUIDANCE CONTINUES TO
HIGHLIGHT ANOTHER STRONG MID-LATITUDE CYCLONE ACROSS THE CENTRAL
CONUS WEDNESDAY INTO THURSDAY MORNING. FORECAST UNCERTAINTY IS
QUITE HIGH LOCALLY AS THE ASSOCIATED WARM FRONT IS FAVORED TO
SETTLE ACROSS THE WESTERN GREAT LAKES REGION. ANY PUSH INTO THE
WARM SECTOR OF THIS SYSTEM WILL BRING AN INCREASE IN SEVERE
STORM POTENTIAL.
KLUBER/PETR
AVIATION /18Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 1249 PM CDT FRI MAR 28 2025
KEY AVIATION MESSAGES FOR THE CURRENT TAF PERIOD:
- SCATTERED SHOWERS ENDING AND MOVING EAST OF THE REGION EARLY
THIS AFTERNOON
- STRONG SOUTHWESTERLY WIND GUSTS AROUND 35 KNOTS THIS
AFTERNOON
- PERIOD OF LLWS TONIGHT AND INTO EARLY SATURDAY MORNING
- A FRONT MOVES DOWN THE LAKE SATURDAY AFTERNOON SWITCHING
WINDS TO THE NORTHEAST WITH THE CHANCE FOR SOME POST-FRONTAL
RAIN
SCATTERED SHOWERS PERSIST EARLY THIS AFTERNOON. THE GOOD NEWS
IS, THE NORTHERN BOUNDARY OF THE SHOWERS WILL CONTINUE TO
ERODE WHICH WILL RESULT IN MOSTLY DRY TAFS FROM CHICAGO TO
ROCKFORD. HOWEVER, THERE IS ANOTHER BOUNDARY THAT IS SLOWLY
MOVING NORTHWARD THAT IS KEEPING AN AREA OF CONVERGENCE WHERE
SCATTERED SHOWERS WILL PERSIST FOR THE NEXT HOUR. WHILE THERE
IS LOWER CONFIDENCE ON THE EXACT END TIME TO THE SHOWERS, DRIER
CONDITIONS ARE EXPECTED THIS AFTERNOON.
THE MAIN AVIATION IMPACT THIS AFTERNOON WILL BE FROM THE STRONG
SOUTHWESTERLY WIND GUSTS BEHIND THE PREVIOUSLY MENTIONED
BOUNDARY MOVING NORTH. THE STRONGEST GUSTS IN THE TAF WERE
CAPPED AROUND 35 KNOTS, BUT ISOLATED BURSTS UP TO 40 KNOTS ARE
CERTAINLY POSSIBLE (AND ALREADY OBSERVED AT DNV AND CMI).
WIND GUSTS WILL SLOWLY FALL UNDER 30 KNOTS AFTER 00Z. BUT
SHORTLY THEREAFTER, A STRONG LOW LEVEL JET WILL INCREASE TO 55
TO 60 KNOTS AROUND 2000 FEET OFF THE DECK. IT IS ANTICIPATED
THAT SURFACE WIND GUSTS WILL FALL TO THE LEVEL THAT WOULD
CREATE A PERIOD OF LLWS AT AREA TERMINALS OVERNIGHT.
WINDS WILL REMAIN OUT OF THE SOUTHWEST WITH GUSTS BETWEEN 20 TO
25 KNOTS THROUGH THE DAY ON SATURDAY. THERE IS A SLIGHT (20
PERCENT) CHANCE FOR SOME LIGHT SHOWERS TO MOVE IN AROUND GYY IN
THE LATE MORNING/EARLY AFTERNOON, BUT IT WAS KEPT OUT OF THE TAF.
HOWEVER, AT THE END OF THE TAF PERIOD, A FRONT IS EXPECTED TO
MOVE DOWN THE LAKE WHICH WILL CAUSE THE WINDS TO FLIP AROUND TO
THE NORTHEAST, LEAD TO LOWER CIGS AND A CHANCE FOR RAIN.
DK
MARINE
ISSUED AT 655 AM CDT FRI MAR 28 2025
- GALE WARNING IN EFFECT FOR THE ILLINOIS AND PORTIONS OF THE
NORTHWEST INDIANA NEARSHORE WATERS OF LAKE MICHIGAN THIS
AFTERNOON THROUGH TONIGHT.
A SEASONABLY STRONG LOW PRESSURE SYSTEM WILL MOVE FROM THE
NORTHERN PLAINS TOWARD THE GREAT LAKES CAUSING A SURFACE WARM
FRONT TO LIFT NORTHWARD THROUGH THE REGION TODAY. BEHIND THE
FRONT, SOUTHWESTERLY WINDS WILL INCREASE QUICKLY IN MAGNITUDE IN
THE AFTERNOON. GALE FORCE GUSTS IN EXCESS OF 35 KTS ARE
EXPECTED, AND WILL THEN LAST INTO THE EVENING HOURS, ALTHOUGH
GALES MAY BECOME MORE INTERMITTENT WITH TIME, PARTICULARLY
ACROSS THE INDIANA NEARSHORE ZONES. A FEW GALES ABOVE 40 KTS
APPEAR POSSIBLE DURING THE AFTERNOON, PARTICULARLY ACROSS THE
ILLINOIS NEARSHORE. SINCE WATER TEMPERATURES REMAIN COLD
(LEADING TO STABILITY OVER THE LAKE), THE THREAT FOR GALE FORCE
WINDS WILL BE WITHIN THE FIRST FEW MILES OF THE LAKESHORE.
NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...GALE WARNING UNTIL 3 AM CDT SATURDAY FOR THE IL AND IN
NEARSHORE WATERS.
VISIT US AT WEATHER.GOV/CHICAGO
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