431
FXUS63 KIWX 292323
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
723 PM EDT WED JUL 29 2026
KEY MESSAGES
- DRY AND SEASONABLE WEATHER CONTINUES WITH LOW HUMIDITY INTO
FRIDAY.
- CHANCES FOR RAIN AND STORMS INCREASE TO 40-70% LATE FRIDAY INTO
SATURDAY. SEVERE WEATHER IS NOT EXPECTED AT THIS TIME.
DISCUSSION
ISSUED AT 300 PM EDT WED JUL 29 2026
AN UPPER SPEED MAX IS PROGRESSING ACROSS THE LOWER OHIO VALLEY
AND EVENTUALLY THE MID ATLANTIC REGION INTO THIS EVENING. A
MID/UPPER LEVEL RIDGE BUILDING INTO THE REGION BEHIND THIS
FEATURE WILL ALLOW LOW LEVEL COLD AIR ADVECTION TO CONTINUE
ACROSS THE AREA TONIGHT. THE COMBINATION OF MOSTLY CLEAR SKIES
AND RESIDUAL NEAR SFC MOISTURE COULD ALLOW FOR ANOTHER MORNING
OF PATCHY SHALLOW FOG EARLY THURSDAY AM, BUT CURRENTLY NOT
EXPECTING THIS TO BE A MAJOR CONCERN. GOOD RADIATIONAL COOLING
CONDITIONS WILL RESULT IN BELOW NORMAL LOW TEMPS TONIGHT FROM
MID 50S TO LOWER 60S.
THE MID/UPPER LEVEL WAVE PATTERN WILL BECOME SOMEWHAT STAGNANT
TOMORROW AND THURSDAY WITH LITTLE MOVEMENT IN MID/UPPER LEVEL RIDGE
AXIS ACROSS THE REGION AND PERSISTENCE OF A LOW LEVEL ANTICYCLONE.
THIS WILL RESULT IN LIGHT NORTHWEST WINDS FOR THURSDAY, EVENTUALLY
BECOME LIGHT SOUTHWEST ON FRIDAY AS THE RIDGE AXIS BEGINS TO SHIFT
OFF TO THE EAST.
WATER VAPOR IMAGERY THIS AFTERNOON DEPICTS NEXT NOTABLE UPPER
LEVEL SHORT WAVE SHIFTING ACROSS CENTRAL CA/NV THIS AFTERNOON.
THIS FEATURE WILL SLOWLY RIDE THE LONGWAVE RIDGE ACROSS WESTERN
CONUS. A PLAINS LOW LEVEL JET AHEAD OF THIS SYSTEM WILL RESULT
IN STRONG LOW MOISTURE CONVERGENCE ACROSS THE NORTHERN PLAINS
LATE THURSDAY. GUIDANCE CONTINUES TO INDICATE ENHANCEMENT OF
THIS RIDGE TOPPING SHORT WAVE FROM CONVECTION, WITH A LARGE PART
OF NEGATIVE LOW LEVEL HEIGHT TENDENCIES AND EASTWARD
PROGRESSION OF ASSOCIATED LOW LEVEL CYCLONIC FLOW TIED TO THIS
INDUCED LOW/MID LEVEL DIABATIC PV ANOMALY. SOME SOUTHEAST FLOW
ON EASTERN PERIPHERY OF THIS LOW LEVEL CIRCULATION MAY SLOW
TRANSPORT OF BEST LOW LEVEL MOISTURE AXIS INTO THE AREA ON
FRIDAY, WITH BEST CHANCES OF SHOWERS/ISOLATED STORMS ON FRIDAY
AFTERNOON SOUTH OF US ROUTE 30 ACROSS NORTHWEST INTO PORTIONS OF
NORTH CENTRAL INDIANA.
BETTER ELEVATED MOISTURE ADVECTION WITH THIS FEATURE STILL LOOKS TO
WORK INTO THE AREA FRIDAY NIGHT INTO SATURDAY MORNING. LOW LEVEL
REFLECTION OF THIS SYSTEM STILL LOOKS LIKELY TO TRACK SOUTH OF THE
LOCAL AREA WHICH MAY SET UP A PERIOD OF DEFORMATION FORCING INTO
SATURDAY AFTERNOON/EARLY EVENING. SLOW MOVING NATURE OF THIS FORCING
COULD ALLOW FOR SOME LOCALIZED DECENT RAINFALL AMOUNTS, BUT TREND IN
MEDIUM RANGE GUIDANCE HAS BEEN TO SLIGHTLY MORE PROGRESSION WHICH
SHOULD PREVENT SIGNIFICANT HYDRO ISSUES. SEVERE WEATHER IS
CURRENTLY NOT EXPECTED AS BETTER AXIS OF WEAK/MODERATE
INSTABILITY APPEARS TO BE FAVORED WELL SOUTH OF THE LOCAL AREA.
PASSAGE OF FRIDAY/SATURDAY SYSTEM WILL LEAVE A BROAD LOW LEVEL
THERMAL TROUGH IN ITS WAKE AND SLIGHTLY BELOW NORMAL TEMPERATURES
FOR THE REMAINDER OF THE WEEKEND INTO MONDAY. MID/UPPER LEVEL FLOW
WILL GRADUALLY DEAMPLIFY NEXT WEEK WHICH WILL EVENTUALLY ALLOW
EASTWARD MIGRATION OF WARMER CENTRAL CONUS LOW LEVEL TEMPS. THIS
DEAMPLIFIED PATTERN WILL ALSO RESULT IN SOME INCREASED CHANCES OF
SHOWERS/STORMS TOWARD THE END OF THE PERIOD, ALTHOUGH CONFIDENCE IN
TIMING OF INCREASED CHANCES IS LOW AT THIS TIME.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 721 PM EDT WED JUL 29 2026
LAKE BREEZE HAS PASSED THROUGH KSBN, BRINGING A TEMPORARY SHIFT
IN WINDS TO FROM THE NW. WINDS WILL DIMINISH AT BOTH SITES LATER
THIS EVENING AND REMAIN ON THE LIGHTER SIDE THURSDAY WITH NO
FLIGHT CONCERNS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...FISHER
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