668
FXUS63 KIWX 271744
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
144 PM EDT SUN SEP 27 2026
KEY MESSAGES
- DRY CONDITIONS PERSIST THROUGH AT LEAST TUESDAY WITH SLOWLY
MODERATING TEMPERATURES.
- THE NEXT CHANCE (50-70%) OF RAIN ARRIVES ON THURSDAY.
THUNDERSTORMS ARE POSSIBLE BUT SEVERE WEATHER AND HEAVY RAIN
ARE NOT EXPECTED.
- CONFIDENCE IN THE FORECAST BEYOND THURSDAY IS LOW BUT IT DOES
APPEAR TO TREND TOWARD COOLER AND DRIER WEATHER RETURNING.
DISCUSSION
ISSUED AT 144 PM EDT SUN SEP 27 2026
VERY LITTLE CHANGE IN THE FORECAST OVER THE NEXT 24-48 HOURS AS
SURFACE AND UPPER AIR PATTERN REMAINS RELATIVELY STAGNANT THANKS TO
BOOKEND LOWS OVER NEW ENGLAND AND CALIFORNIA. THIS LEAVES PERSISTENT
MID/UPPER LEVEL RIDGING OVER THE GREAT LAKES. THESE FEATURES DO
SLOWLY DRIFT EASTWARD DURING THIS TIME WITH SOME MODEST RETURN FLOW
STARTING LATER TUE BUT OVERALL A LEAN TOWARD PERSISTENCE IS
WARRANTED, ESPECIALLY FOR MONDAY. THIS ENTAILS ANOTHER NIGHT OF GOOD
RADIATIONAL COOLING (THOUGH PROBABLY NOT QUITE AS COLD AS LAST
NIGHT) FOLLOWED BY A LARGE DIURNAL SWING INTO MONDAY. CONTINUED
PREVIOUS TREND OF SIGNIFICANTLY REDUCING NBM DEWPOINTS AND ENHANCING
THE DIURNAL TEMP RANGES A BIT. SOME PATCHY FOG POSSIBLE AGAIN
TONIGHT BUT THE SIGNALS IN GUIDANCE ARE MIXED AND MUTED WITH ANOTHER
DAY OF DEEP MIXING/DRYING THIS AFTERNOON SO WILL HOLD OFF ON
MENTIONING FOG IN THE FORECAST FOR NOW. WITH SLOWLY INCREASING
RETURN FLOW AND DEEP MIXING TUE-WED, HIGHS COULD MAKE A RUN AT UPPER
70S/AROUND 80F.
STILL A FAIR DEGREE OF VARIABILITY IN NUMERICAL GUIDANCE HEADING
INTO THE LATTER HALF OF THE WEEK. UNCERTAINTY CENTERS AROUND
CALIFORNIA CLOSED LOW INTERACTING WITH THE REMNANTS OF HURRICANE
POLO. THE SPEED OF A NORTHERN STREAM UPPER JET TRAVERSING CANADA IS
ALSO IN QUESTION AND THE INTERACTION OF THESE FEATURES WILL DICTATE
OUR SENSIBLE WEATHER LATE-WEEK. EARLIER NOTED TREND TOWARD A SLOWER
JET/TROUGH AND ASSOCIATED SURFACE BOUNDARY CONTINUED IN THE 12Z
SUITE, SUGGESTING PRECIP MAY NOT START HERE UNTIL WELL INTO THU.
REASONABLE AGREEMENT ON THIS WITHIN THE ENSEMBLE GUIDANCE SO NBM
POP'S REMAIN VERY LOW WED INTO WED NIGHT BUT DO WANT TO SEE MORE
TEMPORAL CONSISTENCY BEFORE LATCHING ON ENTIRELY. THERE HAS ALSO
BEEN A TREND TOWARD A MORE PROGRESSIVE FRONTAL PASSAGE LATE THU THAT
MAY CLEAR OUR AREA ENTIRELY BY FRI. THIS WOULD ALLEVIATE ANY HEAVY
RAIN CONCERNS. SEVERE WEATHER CHANCES ALSO SEEM VERY LOW GIVEN LACK
OF STRONG MIDLEVEL FORCING ALONG THE ACTUAL SURFACE FRONT AND
OVERALL MODEST LOW LEVEL MOISTURE/INSTABILITY AS WE ENTER OCT.
HOWEVER, WOULD STILL LIKE TO SEE MORE TEMPORAL CONSISTENCY BEFORE
LATCHING ON TO ANY ONE SCENARIO. STILL PLENTY OF DETAILS TO WORK OUT
FOR LATE-WEEK BUT OVERALL THE RISK OF STRONG STORMS/HEAVY RAIN DOES
APPEAR LOW.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1132 AM EDT SUN SEP 27 2026
LIGHT WINDS WILL PREVAIL AGAIN WITH NO MAJOR FLIGHT CONCERNS. AS
HAS BEEN THE CASE THE PAST COUPLE OF MORNINGS, CAN'T RULE OUT
SOME PATCHY SHALLOW FOG OR STRATUS. NOT WORTH ANY MENTION AT
THIS POINT WITH LOW CONFIDENCE IF ANY OF THE SITES WILL BE
IMPACTED.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...FISHER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page