112
FXUS63 KIWX 071729
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1229 PM EST SAT MAR 7 2026
KEY MESSAGES
- SPORADIC 35 TO 45 MPH GUSTS AS WELL AS BRIEF RAIN WILL BE
POSSIBLE THIS AFTERNOON AS A COLD FRONT MOVES THROUGH.
- DRY WEATHER RETURNS FOR SUNDAY AND MONDAY, BUT MORE SHOWERS
AND STORMS EXPECTED FOR TUESDAY INTO WEDNESDAY. SOME SEVERE
RISK AND A POTENTIAL OF HEAVY RAIN WILL NEED TO BE MONITORED
WITH THIS SYSTEM.
- COOLER TEMPERATURES RETURN BRIEFLY TODAY BEHIND A COLD FRONT
BUT WARM BACK TO NEAR 70 DEGREES FOR MONDAY AND TUESDAY.
DISCUSSION
ISSUED AT 234 AM EST SAT MAR 7 2026
A COUPLE OF CONVECTIVELY ENHANCED SHORT WAVES WILL CONTINUE TO LIFT
NORTHEAST ACROSS THE MID/UPPER MS VALLEY AND WESTERN GREAT LAKES
THIS MORNING. MEANWHILE, A LARGER SCALE UPPER TROUGH WILL CONTINUE
TO GET SHEARED AND ACQUIRE A MORE POSITIVE TILT ACROSS THE UPPER MS
VALLEY ALLOWING FOR EVENTUAL COLD FRONT PROGRESSION ACROSS THE AREA
THIS AFTERNOON INTO EARLY EVENING.
WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUE THIS MORNING
FROM NORTHERN ILLINOIS INTO EASTERN MISSOURI, TIED MORE INTO PRE-
FRONTAL TROUGH FORCING/MOISTURE AXIS. THIS CONVECTION HAS BEEN
RELATIVELY LOOSELY ORGANIZED BUT SEVERAL REPORTS OF 40-50 MPH GUSTS
HAVE COME OUT OF NW ILLINOIS AND THE QUAD CITIES AREA THIS MORNING
GIVEN STRONG BACKGROUND FLOW. THE BEST SHEAR/INSTABILITY BALANCE
APPEARS TO BE CONTINUING ACROSS SOUTHWEST IL INCLUDING THE ST. LOUIS
METRO AREA THIS MORNING WITH SOME 40+ MPH REPORTS ALONG A BOW-LIKE
FEATURE. PLENTY OF MOISTURE IN THE WARM SECTOR WITH UPSTREAM DEW
POINTS IN THE LOW-MID 60S SHOULD GET PULLED NORTHWARD THIS MORNING
VIA A STRONG LOW LEVEL JET WHICH WILL SUPPORT AN MUCAPE AXIS OF 500-
1000 J/KG LIFTING ACROSS PORTIONS OF NORTHERN IN/NORTHWEST OHIO
TOWARD DAYBREAK, ALSO AIDED BY SOME MODERATELY STEEP 7-7.5 DEGREE
MID LEVEL LAPSE RATES. ANALYSIS OF BACKGROUND SHEAR PROFILES IS
SOMEWHAT COMPLICATED BY CONVECTIVELY ENHANCED NATURE OF THESE
SHORT WAVES, BUT GIVEN APPROACH OF THIS MUCAPE AXIS AND
SUFFICIENT SHEAR, SOME ISOLATED WIND THREAT IS POSSIBLE THIS
MORNING IN THE 12Z-17Z TIME WINDOW AND MAY BE GREATEST SOUTH OF
US 30 WHERE INSTABILITY MAY BE MAXIMIZED. WITH LOW LCLS AND
ELONGATED HODOGRAPHS IN LOWEST FEW KILOMETERS, CAN'T COMPLETELY
RULE OUT A BRIEF WEAK TORNADO, PARTICULARLY ACROSS EASTERN
LOCATIONS WHERE SOME BETTER DESTABILIZATION IS POSSIBLE BEFORE
PRE-FRONTAL TROUGH FEATURE EXITS EARLY THIS AFTERNOON , BUT
OVERALL LIMITED INSTABILITY AND POTENTIAL OF THIS MORNING'S
CONVECTION TO BE SLIGHTLY ELEVATED ARGUES FOR MAINLY AN ISOLATED
WIND THREAT THROUGH MIDDAY.
FOLLOWING DEPARTURE OF THE PRE-FRONTAL TROUGH, SOME ADDITIONAL
STORMS ARE EXPECTED TO DEVELOP ALONG ASSOCIATED COLD FRONT. NEAR
TERM GUIDANCE CONTINUES TO PAINT SOME DIFFERENT IDEAS IN THERMO
PROFILES ALONG AND NEAR THIS COLD FRONT WITH SOME DEPENDENCY ON
EXTENT OF LOW LEVEL MIXING. SOME MID LEVEL SYNOPTIC COOLING IS
POSSIBLE THIS AFTERNOON WITH LAGGING MID LEVEL FRONTAL ZONE THAT
COULD YIELD A NARROW CORRIDOR OF 500-1000 J/KG OF SURFACE BASED
CAPE IN VICINITY OF THE COLD FRONT. IF THIS TYPE OF INSTABILITY
CAN BE REALIZED, CANNOT RULE OUT AN ISO WIND/HAIL THREAT WITH
THE COLD FRONT, BUT THIS CONTINUES TO BE AN ITEM OF LOW
CONFIDENCE WITH THE UNCERTAINTY IN INSTABILITY PROFILES BY THIS
TIME.
OTHERWISE TODAY, WINDY CONDITIONS ARE EXPECTED TO DEVELOP WITH WIND
GUSTS OF 25 TO 35 MPH. PASSAGE OF THE COLD FRONT MAY ALSO PROMOTE A
BRIEF PERIOD OF STRONG WINDS MIXING TO SURFACE. HIGHS ARE EXPECTED
IN THE MID-UPPER 60S TODAY, BUT TEMPS WILL FALL THIS AFTERNOON
ACROSS THE WEST BEHIND THE COLD FRONT.
DRY CONDITIONS RETURN TONIGHT THROUGH MONDAY WITH FOCUS SHIFTING TO
A LARGER SCALE SYNOPTIC SYSTEM FOR THE MIDDLE OF NEXT WEEK. MEDIUM
RANGE GUIDANCE HAS LONG BEEN ADVERTISING A STRONG EASTERN PACIFIC
NET INDUCING UPPER TROUGH AMPLIFICATION ACROSS THE NORTHERN ROCKIES
WHILE AT THE SAME TIME STRONG MOISTURE TRANSPORT OVERSPREADS
GREAT LAKES/OHIO VALLEY DOWNSTREAM OF A SOUTHERN STREAM CUT-OFF
UPPER TROUGH. POTENTIAL PHASING OF THESE SYSTEMS AND EXPECTED
STRONG DOWNSTREAM PRE-EXISTING BAROCLINIC ZONE STILL ARGUES FOR
KEEPING LIKELY-CATEGORICAL POPS FOR LATER TUESDAY-WEDNESDAY
PERIOD. DEPENDING ON TRACK OF LOW LEVEL FEATURES, SOME SEVERE
THREAT MAY ACCOMPANY THIS SYSTEM ALONG WITH A POTENTIAL OF SOME
HEAVY RAINFALL AS INITIAL FRONTAL WAVE PHASE OF THIS SYSTEM
COULD BE FOLLOWED BY STRONGER SYNOPTIC/COLD FRONTAL FORCING ON
WEDNESDAY.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1225 PM EST SAT MAR 7 2026
A PREFRONTAL TROUGH HAD THE INITIAL SHOWERS AND STORMS MAINLY SOUTH
AND EAST OF THE TERMINALS THIS MORNING. A COLD FRONT IS EXPECTED TO
SWING THROUGH BEHIND, BUT INSTABILITY APPEARS TO BE THE MAIN
LIMITING FACTOR FOR THUNDERSTORMS. WILL CONTINUE TO KEEP MVFR
PREVAILING AT SBN BUT CANNOT RULE OUT IFR EARLY IN THE TAF PERIOD
AND THEN AGAIN OVERNIGHT. EARLY VFR AT FWA TRENDS DOWN INTO MVFR
LATE THIS AFTERNOON AND CONTINUES INTO SUNDAY AM. THE COMBINATION OF
MOISTURE AND COOLER TEMPERATURES HELPS THIS OUT. A RETURN TO VFR
LOOKS MORE LIKELY MID TO LATE MORNING ON SUNDAY.
WIND-WISE, GUSTS 25 TO 35 KTS WILL BE POSSIBLE ESPECIALLY ALONG THE
FRONT, BUT WOULDN'T BE SURPRISED TO SEE SPORADIC GUSTS APPROACHING
THAT MAGNITUDE OUT AHEAD OF THE FRONT AS WELL WITH SHOWERS MOVING
THROUGH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...MARSILI
AVIATION...ROLLER
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