217
FNUS73 KLOT 101056 CCA
FWSLOT
SPOT FORECAST FOR OLD CHICAGO...CORRECTED
NATIONAL WEATHER SERVICE CHICAGO IL
556 AM CDT TUE MAR 10 2026
FORECAST IS BASED ON IGNITION TIME OF 0700 CDT ON MARCH 10.
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER
SERVICE.
PLEASE CONTACT OUR OFFICE AT (815) 834-0666 IF YOU HAVE QUESTIONS
OR CONCERNS WITH THIS FORECAST.
DISCUSSION
A SHARP AND SHALLOW COLD FRONT IS MOVING QUICKLY SOUTHWARD OUT OF
FAR NORTHERN ILLINOIS EARLY THIS MORNING. BEHIND THE FRONT, WINDS
WILL SHIFT OUT OF THE NORTHEAST AND TEMPERATURES AND MIXING HEIGHTS
WILL FALL VERY QUICKLY. THERE IS UNCERTAINTY REGARDING EXACTLY
WHEN OR IF THE FRONT WILL ARRIVE AT THE BURN SITE, WITH SOME
GUIDANCE THIS MORNING INDICATING THE TEMPERATURE FALL MAY BEGIN AS
EARLY AS ABOUT 11 AM TO NOON OR AS LATE AS 4 PM WITH THE FRONT
STALLING JUST NORTH OF THE BURN SITE. BASED ON THE LATEST
OBSERVATIONS, AN EARLIER ARRIVAL TOWARDS 1 PM APPEARS POSSIBLE
WHICH COULD RESULT IN SIGNIFICANTLY LOWER TEMPERATURES, RHS, AND
MIXING HEIGHTS THAN PRESENTLY FORECAST AT THE BURN SITE. IF THE
FRONT PASSES, MIXING HEIGHTS WILL FALL QUICKLY TO UNDER 1000 FEET
AND TEMPERATURES WILL FALL INTO THE UPPER 40S/LOWER 50S.
ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE AS
EARLY AS ABOUT 3-4 PM, WITH COVERAGE BECOMING NUMEROUS TOWARDS AND
AFTER SUNSET. SOME STORMS WILL BE SEVERE WITH A THREAT FOR LARGE
HAIL, DAMAGING WINDS AND FLASH FLOODING, AND POSSIBLY A TORNADO.
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE EVENING AND
POSSIBLY EARLY WEDNESDAY MORNING. A COLD FRONT WILL SHIFT WINDS
OUT OF THE NORTHWEST ON WEDNESDAY WITH CONTINUED SHOWER CHANCES
THROUGH AT LEAST EARLY AFTERNOON.
REST OF TODAY
SKY/WEATHER.........PARTLY CLOUDY THEN BECOMING MOSTLY CLOUDY.
PATCHY FOG IN THE MORNING. CHANCE OF SHOWERS AND
THUNDERSTORMS LATE IN THE AFTERNOON.
TEMPERATURE.........58 AT IGNITION...MAX 71.
RH..................100 PERCENT AT IGNITION...MIN 61 PERCENT.
WIND (20 FT)........WINDS SOUTHWEST AT 7 MPH AT
IGNITION...OTHERWISE SOUTHWEST WINDS 7 TO 8 MPH
SHIFTING TO THE SOUTHEAST 9 TO 12 MPH IN THE
AFTERNOON. GUSTY AND ERRATIC WINDS EXPECTED
NEAR THUNDERSTORMS.
CHANCE OF PCPN......50 PERCENT.
TRANSPORT WINDS.....SOUTH 10 TO 14 MPH SHIFTING TO THE SOUTHEAST 15
TO 16 MPH LATE IN THE AFTERNOON.
MIXING HEIGHT.......900 FT AGL AT IGNITION...OTHERWISE 4000 FT AGL.
SMOKE DISPERSAL.....POOR /10200 KNOT-FT/ AT IGNITION. MAX...GOOD
/51800 KNOT-FT/.
TIME (CDT) 7 AM 9 AM 11 AM 1 PM 3 PM 5 PM
SKY (%).........40 46 51 57 65 75
WEATHER COV.....PATCHY PATCHY S CHC CHANCE
WEATHER TYPE....FOG FOG NONE NONE RNSHWR RNSHWR
TEMP............58 62 68 71 66 62
RH..............100 94 79 63 62 71
20 FT WIND......210/7 220/8 210/8 140/9 160/12 160/13
20 FT WIND GUST.13 16 15 14 17 20
MIX HGT (FT)....900 1300 2500 3500 4000 2900
TRANSP WIND DIR.210 210 210 180 160 150
TRANSP WIND SPD.14 13 12 10 13 15
CHC OF PCPN (%).0 0 0 10 20 50
VRATE KT-FT/1K..10 14 25 31 46 38
TONIGHT
SKY/WEATHER.........CLOUDY. RAIN SHOWERS WITH THUNDERSTORMS LIKELY.
TEMPERATURE.........MIN 46.
RH..................MAX 100 PERCENT.
WIND (20 FT)........SOUTHEAST WINDS 10 TO 12 MPH SHIFTING TO THE
WEST AROUND 10 MPH AFTER 3 AM. GUSTY AND
ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS.
GUSTY AND ERRATIC WINDS EXPECTED NEAR
THUNDERSTORMS.
CHANCE OF PCPN......90 PERCENT.
TRANSPORT WINDS.....SOUTHEAST 12 TO 16 MPH SHIFTING TO THE
NORTHWEST AROUND 13 MPH EARLY IN THE MORNING.
MIXING HEIGHT.......500 FT AGL.
SMOKE DISPERSAL.....FAIR (18700 KNOT-FT) EARLY IN THE EVENING
DECREASING TO POOR (5400 KNOT-FT) LATE IN THE
NIGHT.
TIME (CDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM
SKY (%).........81 88 89 94 97 100
WEATHER COV.....LIKELY DEFNTE DEFNTE DEFNTE DEFNTE DEFNTE
WEATHER TYPE....RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR
TEMP............59 58 59 59 57 54
RH..............82 99 100 97 92 92
20 FT WIND......130/13 130/13 180/12 200/13 230/12 280/10
20 FT WIND GUST.20 18 17 17 17 17
MIX HGT (FT)....1600 600 600 800 1000 1300
TRANSP WIND DIR.130 130 180 200 230 280
TRANSP WIND SPD.13 12 16 17 17 15
CHC OF PCPN (%).70 80 90 90 80 80
VRATE KT-FT/1K..18 5 8 12 16 17
WEDNESDAY
SKY/WEATHER.........CLOUDY. CHANCE OF THUNDERSTORMS EARLY IN THE
MORNING. RAIN SHOWERS IN THE MORNING, THEN
CHANCE OF RAIN SHOWERS IN THE AFTERNOON.
TEMPERATURE.........MAX 47.
RH..................MIN 75 PERCENT.
WIND (20 FT)........NORTHWEST WINDS 10 TO 12 MPH INCREASING TO 14
TO 17 MPH WITH GUSTS TO AROUND 35 MPH IN THE
LATE MORNING AND AFTERNOON. GUSTY AND ERRATIC
WINDS EXPECTED NEAR THUNDERSTORMS.
CHANCE OF PCPN......90 PERCENT.
TRANSPORT WINDS.....NORTHWEST 15 TO 20 MPH INCREASING TO 29 TO 30
MPH.
MIXING HEIGHT.......3600 FT AGL.
SMOKE DISPERSAL.....FAIR (13600 KNOT-FT) EARLY IN THE MORNING
INCREASING TO EXCELLENT (95300 KNOT-FT) IN THE
AFTERNOON.
TIME (CDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM
SKY (%).........100 100 100 100 92 90
WEATHER COV.....DEFNTE DEFNTE DEFNTE DEFNTE CHANCE CHANCE
WEATHER TYPE....RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR
TEMP............50 47 47 45 44 41
RH..............88 95 100 95 87 83
20 FT WIND......300/12 300/13 320/15 310/16 320/17 320/20
20 FT WIND GUST.20 20 24 26 30 35
MIX HGT (FT)....1200 1000 1100 1700 2600 3500
TRANSP WIND DIR.300 300 320 310 320 320
TRANSP WIND SPD.15 15 17 20 26 30
CHC OF PCPN (%).80 90 90 90 50 30
VRATE KT-FT/1K..15 14 17 29 59 92
FORECASTER...CARLAW
REQUESTED BY...LEE HELGESON
TYPE OF REQUEST...PRESCRIBED
.TAG 2605256.0/LOT
.DELDT 03/10/26
.FORMATTERVERSION 2.0.0
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