113
FXUS63 KIWX 300441
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1241 AM EDT MON JUN 30 2025
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE TONIGHT MAINLY
NORTHWEST INDIANA AND EXTENDING INTO NORTHEAST INDIANA ALONG
AND SOUTH OF US ROUTE 24.
- RAIN/STORMS ARE POSSIBLE MONDAY MORNING, THEN LIKELY MONDAY AFTERNOON
AND EVENING. A FEW STORMS COULD BE STRONG TO SEVERE WITH
DAMAGING WINDS AND HEAVY RAINFALL.
- DRY, SEASONABLE, AND LESS HUMID BY MID TO LATE IN THE WEEK.
UPDATE
ISSUED AT 919 PM EDT SUN JUN 29 2025
ISOLATED HEAVY RAINFALL POTENTIAL ACROSS NW INDIANA SHOULD
DIMINISH IN THE NEXT HOUR OR TWO AS SOME WEAK SURFACE BASED CIN
DEVELOPS. STRONG LOW LEVEL MOISTURE GRADIENT AND WEAK STEERING
FLOW LED TO A FEW POCKETS OF HEAVIER RAINFALL THIS AFTERNOON OF
2 TO 4 INCHES (LOCALLY HIGHER), MAINLY ACROSS PORTIONS OF
WHITE/CASS IN COUNTIES AND ACROSS SOUTHERN WELLS IN COUNTY.
FORECAST CONFIDENCE IN POPS FOR THE REMAINDER OF THE NIGHT IS
SOMEWHAT ON THE LOW SIDE. BROAD LOW LEVEL THETA-E GRADIENT
SPRAWLED FROM NORTHEAST ILLINOIS INTO CENTRAL INDIANA SHOULD
MIGRATE EASTWARD AS RELATIVELY WEAK LOW LEVEL FLOW VEERS MORE
WESTERLY IN RESPONSE TO SOME UPPER RIDGE DAMPENING BY THE
PRIMARY UPSTREAM TROUGH ACROSS THE NORTHERN PLAINS. THIS WEAK
INCREASE IN ELEVATED MOISTURE MAY BE ENOUGH IN COMBINATION WITH
SOME SMALLER SCALE CONVECTIVELY ENHANCED SHORT WAVES FROM IL/MO
FOR ISOLATED SHOWERS AND STORMS OVERNIGHT, OR POCKETS OF WEAKER
MULTICELL STORMS DURING THE OVERNIGHT HOURS. WILL KEEP WITH
GENERAL 20-30 POPS FOR THE OVERNIGHT HOURS, BUT THIS WILL LIKELY
NEED TO BE REFINED OVER NEXT SEVERAL HOURS.
DISCUSSION
ISSUED AT 231 PM EDT SUN JUN 29 2025
A WARM FRONT HAS LIFTED NORTHWEST ACROSS THE AREA TODAY, WHICH WILL
ALLOW FOR HIGHS IN THE MID TO UPPER 80S THIS AFTERNOON ALONGSIDE A
NOTICEABLE INCREASE IN HUMIDITY. SOUTHERLY LOW-LEVEL FLOW HAS
HELPED TO PULL IN MOISTURE FROM THE GULF, WHICH HAS BROUGHT
DEWPOINTS UP INTO THE LOW 70S TODAY. HEAT INDICES ARE EXPECTED
TO PEAK IN THE LOW TO MID 90S THIS AFTERNOON. A FEW ISOLATED
SHOWERS/STORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING
ACROSS NORTH-CENTRAL INDIANA, MAINLY SOUTH OF US 24 AND WEST OF
US 31.
WAA CONTINUES INTO THE DAY ON MONDAY WITH HIGHS IN THE 80S AND
DEWPOINTS IN THE LOW TO MID 70S. AN AREA OF LOW PRESSURE WILL LIFT
ACROSS THE MIDWEST AND IT'S ATTENDANT COLD FRONT WILL BRING HIGH
CHANCES (60-80%) FOR SHOWERS AND STORMS. WITH THE AFOREMENTIONED
HEAT AND HUMIDITY, THIS SHOULD ALLOW FOR DESTABILIZATION TO
OCCUR DURING THE DAY MONDAY AND FOR THUNDERSTORMS TO DEVELOP.
THE STORM PREDICTION CENTER HAS MAINTAINED THE MARGINAL RISK
(LEVEL 1 OF 5) FOR OUR ENTIRE FORECAST AREA, MEANING A FEW
STORMS COULD BE STRONG TO SEVERE. OVERALL, MONDAY LOOKS FAIRLY
UNIMPRESSIVE AND DISORGANIZED FOR SEVERE WEATHER, ESPECIALLY
CONSIDERING THERE MAY BE SOME SHOWERS TO DEAL WITH IN THE
MORNING. AN INITIAL ROUND OF SCATTERED SHOWERS (NOT AS MUCH
CONFIDENCE IN THUNDERSTORMS) WILL BE POSSIBLE MONDAY MORNING AS
A SHORTWAVE LIFTS OUT OF THE ST LOUIS AREA. A SECOND,
POTENTIALLY STRONGER, ROUND OF STORMS WILL THEN BE POSSIBLE
MONDAY AFTERNOON AND EVENING WITH THE COLD FRONT. MULTICELL
CLUSTERS/A BROKEN LINE OF THUNDERSTORMS SHOULD DEVELOP AHEAD OF
THE COLD FRONT AND SWEEP THROUGH THE AREA. THESE STORMS WILL
HAVE MODEST INSTABILITY (1500-3000 J/KG) TO WORK WITH, HOWEVER
LAPSE RATES WILL BE POOR AND THERE WILL BE LITTLE TO NO SHEAR IN
PLACE AS VERTICAL WIND PROFILES ARE UNIDIRECTIONAL OUT OF THE
SOUTHWEST. LINGERING SHOWERS AND CLOUDS IN THE MORNING AND EARLY
AFTERNOON MAY ALSO HINDER SEVERE CHANCES. CONFIDENCE IN SEVERE
WEATHER IS LOW. IF ANY STORMS DO MANAGE TO REACH SEVERE
THRESHOLDS, THE PRIMARY THREAT WILL BE DAMAGING WINDS. LOCALLY
HEAVY RAIN IS ALSO POSSIBLE WITH LONG, SKINNY CAPE PROFILES, A
DEEP WARM CLOUD LAYER, AND PWATS OF 1.75-2" MONDAY AFTERNOON AND
EVENING.
JULY WILL START ON A SEASONABLE AND DRY NOTE AS SURFACE HIGH
PRESSURE AND AN UPPER LEVEL RIDGE BUILD IN BY MIDWEEK. TUESDAY
THROUGH FRIDAY CURRENTLY LOOKS TO BE MAINLY DRY, WITH LOWER LEVELS
OF HUMIDITY AND SEASONABLE TEMPERATURES. SOME DIURNAL CHANCES FOR
RAIN/STORMS MAY BE POSSIBLE FOR THE 4TH OF JULY AND INTO THE HOLIDAY
WEEKEND DEPENDING ON HOW AMPLIFIED THE UPPER LEVEL RIDGE IS. FOR
NOW, HAVE KEPT POPS LOW AT 20-30% AT TIMES THROUGH THE WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1233 AM EDT MON JUN 30 2025
SHOWERS AND THUNDERSTORMS ARE DEVELOPING NORTH OF KLAF, DRIFTING
NORTHEAST WITHIN THE WARM SECTOR OF A LOW CENTERED NEAR THE UP
OF MICHIGAN. SPC MESOANALYSIS DEPICTS AMPLE INSTABILITY THIS
HOUR AND ACCEPTABLE UPPER-LEVEL SUPPORT FROM A VORT LOBE
ROTATING THROUGH CENTRAL AND SOUTHERN INDIANA. THIS OUGHT TO
KEEP THE PROB30 EARLY THIS MORNING IN PLAY THOUGH CONFIDENCE IS
LOW OVERALL. GREATER CONFIDENCE IN SCATTERED STORMS PASSING
THROUGH IN THE AFTERNOON AHEAD OF AN UPPER-LEVEL TROUGH AND
SUBSEQUENT COLD FRONT. KSBN HAS A REASONABLE OPPORTUNITY TO SEE
TWO ROUNDS OF STORMS. MEANWHILE, THE COLD FRONTAL STORMS APPEAR
UNLIKELY TO ARRIVE TO KFWA GIVEN A DWINDLING TS ENVIRONMENT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
UPDATE...MARSILI
DISCUSSION...JOHNSON
AVIATION...BROWN
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