936
FXUS63 KIWX 122348
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
748 PM EDT FRI SEP 12 2025
KEY MESSAGES
- 20-40% CHANCES FOR RAIN AND STORMS SATURDAY AFTERNOON THROUGH
EARLY SUNDAY. ISOLATED SEVERE WEATHER IS POSSIBLE.
- A PERSISTENT DRY AND WARM PATTERN SETS UP STARTING ON SUNDAY
AND LASTING THROUGH NEXT WEEK. EXPECT HIGHS IN THE UPPER 80S
TO LOW 90S EACH DAY.
- MINIMUM RELATIVE HUMIDITIES AS LOW AS 30% TO 40% NEXT WEEK MAY
BE CONDUCIVE FOR ELEVATED FIRE DANGER.
DISCUSSION
ISSUED AT 236 PM EDT FRI SEP 12 2025
THE ONLY CHANCES FOR RAIN IN THE NEXT 7 DAYS WILL BE SATURDAY
AFTERNOON/EVENING INTO EARLY SUNDAY MORNING. AN UPPER LEVEL RIDGE
CONTINUES TO AMPLIFY OVER THE CENTRAL CONUS; WITH THE FORECAST AREA
ON THE EASTERN EDGE OF THIS BUILDING RIDGE, THERE ARE 20-40% CHANCES
FOR RAIN AND STORMS ON SATURDAY. CLUSTERS OF CONVECTION CURRENTLY
OVER NORTHERN MINNESOTA WILL DIVE SOUTHEAST OVERNIGHT INTO THE DAY
TOMORROW. RAIN AND STORMS CHANCES INCREASE IN OUR NORTHWEST NEAR
LAKE MICHIGAN AROUND MIDDAY SATURDAY AND PROPAGATE
SOUTH/SOUTHEAST DURING THE AFTERNOON AND EVENING ALONG THE
PERIPHERY OF THE RIDGE. A WARM FRONT LIFTS NORTHWARD TONIGHT,
WITH SOUTHERLY WINDS ALLOWING FOR WAA AND DECENT MOISTURE
TRANSPORT BEHIND IT INTO THE DAY TOMORROW. SPC HAS INTRODUCED A
MARGINAL RISK FOR SEVERE WEATHER ON SATURDAY AND WPC HAS
INTRODUCED A MARGINAL RISK FOR LOCALIZED FLASH FLOODING.
FORECAST SOUNDINGS SHOW A MAINLY CAPPED ENVIRONMENT BUT I
WOULDN'T BE SURPRISED IF A FEW STORMS DEVELOP. SHOULD STORMS
DEVELOP, THEY WILL BE CAPABLE OF HEAVY RAIN AND GUSTY WINDS.
ISOLATED SEVERE WEATHER IS POSSIBLE. BEST CHANCES FOR RAIN
TOMORROW INTO EARLY SUNDAY MORNING WILL LIKELY BE ALONG AND EAST
OF THE I-69 CORRIDOR. HAVE LOWERED POPS IN NORTHWEST OHIO DUE
TO WANING A WANING INSTABILITY GRADIENT AND GIVEN A STRONGER
MODEL CONSENSUS ON THE LOCATION OF PRECIPITATION.
FOR SUNDAY AND INTO EARLY NEXT WEEK, AN OMEGA BLOCK PATTERN SETS UP.
THE AFOREMENTIONED RIDGE AXIS WILL MOVE OVER THE MIDWEST AND
GREAT LAKES REGIONS, ALLOWING FOR WARMER TEMPERATURES AND
PERSISTENT DRY CONDITIONS. HIGHS WILL BE IN THE UPPER 80S TO LOW
90S EACH DAY FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK. THE
HUMIDITY WILL BE NOTICEABLE WITH DEWPOINTS IN THE MID 60S.
WHILE NOT UNCOMMON THIS LATE IN THE SUMMER, THE HEAT WILL ALSO
ALLOW FOR LARGE DIURNAL TEMPERATURE SWINGS AS DRY CONDITIONS
PERSIST THROUGH NEXT WEEK. IN FACT, GIVEN THAT WE HAVE BEEN
LACKING SIGNIFICANT RAINFALL SINCE MID AUGUST, DROUGHT IS LIKELY
TO PERSIST AND/OR DEVELOP IN THE COMING WEEKS.
ONE ADDITIONAL CONCERN FOR NEXT WEEK GIVEN THE ABOVE NORMAL
TEMPERATURES AND DRY CONDITIONS IS FIRE DANGER. SUNNY SKIES AND
PERSISTENT WARMTH SHOULD ALLOW FOR MINIMUM AFTERNOON RELATIVE
HUMIDITY VALUES TO DROP BETWEEN 30 TO 40 PERCENT. HOWEVER,
SHOULD ANY GRASS OR BRUSH FIRES DEVELOP, WINDS SHOULD BE LIGHT
ENOUGH THAT IT LIKELY WON'T SPREAD QUICKLY. AVOID OUTDOOR
BURNING!
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 747 PM EDT FRI SEP 12 2025
AN UPPER LEVEL SHORT WAVE TOPPING AN UPPER LEVEL RIDGE ACROSS
THE REGION IS EXPECTED TO DROP SOUTHEAST ACROSS THE WESTERN
GREAT LAKES SATURDAY MORNING. SOME UPTICK IN WESTERLY LOW LEVEL
FLOW AHEAD OF THIS FEATURE SHOULD AID IN LOW LEVEL MOISTURE
ADVECTION FROM THE MID MS RIVER VALLEY. HOWEVER, THE SUBCLOUD
LAYER IS EXPECTED TO REMAIN RELATIVELY DRY WHICH LEADS TO
LIMITED CONFIDENCE IN COVERAGE OF SHOWERS SATURDAY MORNING.
BASED ON PROXIMITY OF LOW LEVEL THETA-E GRADIENT WITH THE
DEVELOPING WARM FRONT, KSBN STILL APPEARS TO HAVE THE BEST
CHANCE OF SHOWERS AND PERHAPS AN ISOLATED STORM SATURDAY MORNING
INTO EARLY AFTERNOON. CONFIDENCE OF ANY NOTABLE SFC- BASED
INSTABILITY REMAINS LOWER FOR KFWA.
ISOLATED TO SCATTERED SHOWERS AND STORMS MAY REDEVELOP
LATER SATURDAY AFTERNOON INTO SATURDAY EVENING AS LOW LEVEL
BOUNDARY STALLS ACROSS THE REGION WITH INSTABILITY GRADIENT
EXTENDING FROM NORTH CENTRAL IL TO NORTHWEST IN. THE MAIN
QUESTION AT THIS FORECAST DISTANCE DEALS WITH EXTENT OF
MID/UPPER LEVEL SYNOPTIC FORCING BY LATER SATURDAY AFTERNOON AS
THE INITIAL SHORT WAVE DEPARTS TO THE EAST. WILL CONTINUE WITH
VCSH MENTION AT THIS FORECAST DISTANCE WITH BEST CHANCES STILL
APPEARING TO BE ACROSS NORTH CENTRAL/NORTHWEST IN WHERE
INSTABILITY MAGNITUDES MAY REACH INTO THE 500-1000 J/KG LATER IN
THE DAY. VFR CONDITIONS SHOULD HOLD THIS PERIOD OUTSIDE OF ANY
LOW PROBABILITY RESTRICTION IN HEAVIER SHOWER OR STORM ACROSS NW
INDIANA.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...JOHNSON
AVIATION...MARSILI
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