957
FXUS63 KLOT 072332
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
532 PM CST SAT FEB 7 2026
KEY MESSAGES
- QUICK SHOT OF SNOW POSSIBLE LATE TONIGHT OVER FAR NE IL AND
NW IN.
- MILDER TEMPERATURES EXPECTED FOR MUCH OF THE UPCOMING WORK
WEEK.
DISCUSSION
ISSUED AT 229 PM CST SAT FEB 7 2026
MID-LEVEL CLOUD COVER WILL CONTINUE TO INCREASE ACROSS THE AREA
INTO THIS EVENING IN ASSOCIATION WITH OUR NEXT QUICKLY
APPROACHING LOW AMPLITUDE SHORTWAVE IMPULSE RIDING THE NORTHWEST
FLOW INTO THE REGION TONIGHT. WHILE MUCH OF THE AREA WILL SEE
CLOUD COVER AROUND TONIGHT, WE DO CONTINUE TO MONITOR THE
POTENTIAL FOR A QUICK HIT OF LIGHT ACCUMULATING SNOW LATE
TONIGHT ACROSS A SMALL PORTION OF THE AREA. IT IS IMPORTANT TO
NOTE THAT MOST AREAS WILL NOT SEE ANY SNOW AS A RESULT OF THIS
IMPULSE TONIGHT, OWING TO THE VERY DRY LOW-LEVEL AIRMASS IN
PLACE. INSTEAD, WE ARE WATCHING AREAS GENERALLY ALONG A NARROW
NORTH-NORTHWEST TO SOUTH- SOUTHEAST ORIENTED CORRIDOR THAT
EXTENDS FROM SOUTHEASTERN WI AND FAR NORTHEASTERN IL (ESPECIALLY
IN CLOSE PROXIMITY TO LAKE MICHIGAN) SOUTHEASTWARD INTO PARTS
OF NORTHWESTERN IN. FORECAST GUIDANCE CONTINUES TO INSIST THAT
TOP-DOWN SATURATION WILL OCCUR IN THIS CORRIDOR AND SUPPORT A
SHORT PERIOD (2-4 HOURS) OF SNOW LATER TONIGHT. THIS CERTAINLY
SEEMS PLAUSIBLE SINCE THIS IS ALSO THE GENERAL REGION IN WHICH A
TRANSIENT BAND OF FRONTOGENESIS IS FAVORED TO DEVELOP AND
SUPPORT SOME ENHANCED FORCED ASCENT. WE HAVE THUS CONTINUED TO
CONFINE CHANCE TO LOW END LIKELY POPS (30-60% CHANCE) IN THIS
GENERAL AREA OVERNIGHT. THE SHORT DURATION OF SNOW SHOULD RESULT
IN LIGHT AMOUNTS OF A COATING TO PERHAPS LOCALLY UP TO AN INCH.
A LARGE SCALE WEATHER PATTERN CHANGE IS SLATED TO TAKE PLACE
INTO THE FIRST PORTION OF THE UPCOMING WORK WEEK. THIS WILL
OCCUR AS THE PERSISTENT HIGH AMPLITUDE RIDGING OVER WESTERN
NORTH AMERICA BEGINS TO DEAMPLIFY AND TRANSITION THE UPPER-LEVEL
PATTERN ACROSS MOST OF THE COUNTRY INTO A MORE QUASI-ZONAL FLOW
PATTERN (WEST-TO-EAST) FOR A PERIOD NEXT WEEK. OVERALL, THIS
WILL SET THE STAGE FOR A MILDER AIRMASS ACROSS OUR REGION THIS
WEEK AS THE VERY COLD AIRMASS REMAINS NORTH OF THE AREA.
THE THREAT OF PRECIPITATION ALSO LOOKS TO REMAIN LOW (<20%)
ACROSS OUR AREA THROUGH AT LEAST MID-WEEK, OWING TO EXPECTATION
OF WEATHER SYSTEMS TRACKING WELL NORTH AND SOUTH OF OUR AREA.
OUR MILDEST PERIOD THIS WEEK LOOKS TO BE MONDAY INTO TUESDAY,
WHEN HIGH TEMPERATURES LOOK TO TAG 40 DEGREES IN MOST AREAS. A
WEAK COLD FRONT IS EXPECTED TO DROP SOUTHWARD ACROSS THE AREA ON
TUESDAY. THIS SHOULD BRING COOLER (HIGHS IN THE 30S) MORE
SEASONABLE WEATHER BACK INTO THE REGION FOR THE REMAINDER OF THE
WEEK.
THERE REMAINS A LOT OF UNCERTAINTY WITH A POTENTIAL LATE WEEK
SYSTEM. DIDN'T MAKE ANY CHANGES TO THE POPS OFFERED UP BY THE
NBM, BUT THERE CONTINUES TO BE SOME SIGNAL FOR PRECIPITATION
POTENTIAL LATE IN THE WEEK, PARTICULARLY FROM EPS MEMBERS.
KJB
AVIATION /00Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 532 PM CST SAT FEB 7 2026
KEY MESSAGES FOR THE 00Z TAFS"
- PERIOD OF LIGHT SNOW AND MVFR CONDITIONS POSSIBLE FOR CHICAGO
TERMINALS OVERNIGHT.
SURFACE HIGH PRESSURE RIDGE HAS DRIFTED EAST ACROSS THE AREA
THIS AFTERNOON, WITH WINDS IN THE PROCESS OF TURNING LIGHT
EAST-SOUTHEASTERLY. WEAK LAKE BREEZE HAS PUSHED THROUGH ORD/MDW
MAKING FOR A SLIGHTLY MORE EASTERLY DIRECTION ACROSS THE METRO.
OFF TO OUR WEST, AN AREA OF SURFACE LOW PRESSURE ALONG THE
SOUTH DAKOTA/NEBRASKA BORDER WILL PROPAGATE SOUTHEAST ACROSS THE
LOWER MISSOURI VALLEY TONIGHT INTO SUNDAY, WHICH WILL MAINTAIN
MODEST SOUTHEAST WINDS AROUND 10 KT ACROSS THE TERMINALS
THROUGH THE END OF THE TAF PERIOD.
THE SURFACE LOW IS ASSOCIATED WITH A PAIR OF UPPER-LEVEL
DISTURBANCES WHICH WILL TRACK SOUTHEAST ACROSS THE AREA THROUGH
SUNDAY MORNING. INCREASING MID-HIGH LEVEL VFR CLOUDS ARE ALREADY
SPILLING ACROSS THE AREA EARLY THIS EVENING, WITH ASSOCIATED
RADAR RETURNS FROM MN/WI INTO NORTHWEST IL. THE LOW LEVEL AIR
MASS IS QUITE DRY HOWEVER (SURFACE DEW POINTS IN THE SINGLE
DIGITS EITHER SIDE OF 0F), AND THESE RADAR RETURNS CURRENTLY
INDICATE SNOW ABOVE 100-120 KFT SUBLIMATING BEFORE REACHING THE
SURFACE. VARIOUS MODEL GUIDANCE CONTINUES TO INDICATE THAT TOP-
DOWN SATURATION MAY EVENTUALLY ALLOW LIGHT SNOW TO REACH THE
GROUND ACROSS SOUTHEAST WI AND FAR NORTHEAST IL. HAVE THUS
MAINTAINED A PROB30 MENTION FOR LIGHT SNOW AND MVFR VIS FOR THE
CHICAGO TERMINALS (HAVE MAINTAINED DRY FORECAST AT RFD) IN THE
04-10Z PERIOD FOR THIS POTENTIAL. IF SATURATION IS MORE
COMPLETE, CAN'T RULE OUT SOME IFR CONDITIONS ALONG WITH SOME
ACCUMULATIONS OF LESS THAN AN INCH. THE THREAT DOES LOOK TO END
PRIOR TO 12Z.
DRY, VFR CONDITIONS ARE THEN EXPECTED THROUGH THE REMAINDER OF
THE FORECAST PERIOD.
RATZER
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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