654
FXUS63 KIWX 092315
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
715 PM EDT THU APR 9 2026
KEY MESSAGES
- COOLER TEMPERATURES ARRIVE FRIDAY W/ INCREASED CHANCES FOR MEASURABLE
RAINFALL ACROSS MUCH OF THE AREA. THERE IS A 40-60 PERCENT
PROBABILITY OF AT LEAST 0.5 INCH OF RAINFALL FROM LATE TONIGHT
THROUGH FRIDAY, MAINLY NORTH OF US-6.
- TRENDING WARMER AND GENERALLY DRIER THROUGH THE WEEKEND.
- DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CAN BE EXPECTED NEXT
WEEK AS NUMEROUS DISTURBANCES PASS THROUGH THE AREA. AN
OCCASIONAL RISK FOR STRONG TO SEVERE THUNDERSTORMS CANNOT BE
RULED OUT.
DISCUSSION
ISSUED AT 212 PM EDT THU APR 9 2026
MINIMAL CHANGES MADE TO THE INHERITED FORECAST FOR THIS CYCLE W/ THE
MAIN NEAR-TERM FOCUS CONTINUING TO BE CENTERED ON THE NEXT CHANCE
FOR WIDESPREAD RAINFALL IMPACTING A LARGE PART OF THE AREA TONIGHT
THROUGH FRIDAY. THE HIGHEST PROBABILITIES (40-60%) FOR GREATER
TOTALS STILL LOOK TO REMAIN FOCUSED OVER NORTHERN AREAS (MAINLY
NORTH OF US-6), HEAVIEST IN THE 06Z TO 15Z TIME FRAME. WHILE THE
BEST CHANCE OF SHOWERS AND STORMS WILL OCCUR OVERNIGHT WITH THE
FRONTAL PASSAGE, A SUBSET OF AVAILABLE GUIDANCE SUGGESTS SOME LOW-
END POTENTIAL FOR AN EARLIER ROUND OF CONVECTION BETWEEN 00Z AND 06Z
ON THE NOSE OF A SURGE OF LOW-LEVEL WARM AIR ADVECTION EARLY THIS
EVENING. HAVE OPTED TO MAINTAIN 20-30 PERCENT POPS ACROSS NORTHERN
ZONES FOR THIS REASON. OTHERWISE, PREVIOUS FORECAST THINKING REMAINS
LARGELY ON TRACK THROUGH THE PERIOD. / HAMMER
PREVIOUS DISCUSSION (330 AM EDT THU APR 9 2026):
SOME UPTICK IN SHOWER COVERAGE IS EXPECTED THIS EVENING AS A BROAD
UPSTREAM MID LEVEL TROUGH BEGINS TO INDUCE STRONGER LOW LEVEL FLOW
OVER THE STALLED BOUNDARY ACROSS THE SOUTHERN GREAT LAKES.
THIS SETUP SHOULD EVENTUALLY TURN INTO A SOUTHEAST SAGGING
BOUNDARY/LOW LEVEL FGEN FORCING SCENARIO LATE TONIGHT INTO FRIDAY AS
THE MID LEVEL TROUGH TRACKS ACROSS THE GREAT LAKES REGION. WEAK MID
LEVEL LAPSE RATES SHOULD LIMIT THUNDER POTENTIAL TONIGHT INTO
FRIDAY, WITH BEST CHANCE OF FEW EMBEDDED STORMS LATE THIS
EVENING/EARLY OVERNIGHT. SHARPENING FRONTOGENESIS FORCING
TONIGHT/EARLY FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE AT LEAST A
NARROW AXIS OF 0.50"+ OF RAINFALL NORTH OF US ROUTE 6 CORRIDOR, BUT
LESSER RAIN AMOUNTS ARE EXPECTED FOR SOUTHERN LOCATIONS AS STRONGER
FRONTAL FORCING SHOULD BE MIGRATING ACROSS THE EASTERN GREAT LAKES
FRIDAY MORNING. AREA HYDROGRAPHS DO SHOW SOME RESPONSE TO THIS
FORECASTED RAIN, BUT OVERALL RESPONSE IS EXPECTED TO BE MINOR IN
NATURE AND CURRENTLY NOT ANTICIPATED TO HAVE SIGNIFICANT IMPACT ON
THE ONGOING RIVER FLOODING.
SEASONABLE TEMPS ARE EXPECTED ON SATURDAY DUE TO FRIDAY FRONTAL
PASSAGE, WITH TEMPERATURES EXPECTED TO BE NEAR SEASONABLE LEVELS.
MID LEVEL HEIGHT RISES IN WAKE OF FRIDAY MID LEVEL TROUGH SHOULD
YIELD QUIET WEATHER CONDITIONS AT LEAST THROUGH FIRST HALF OF THE
WEEKEND. THE SECOND HALF OF THE WEEKEND WILL FEATURE A RETURN OF
STRONGER LOW LEVEL WARM ADVECTION WITH MORE FAVORED SHORT WAVE TRACK
EXPECTED FROM THE CENTRAL PLAINS TO THE UPPER MS VALLEY/NORTHERN
GREAT LAKES. BY SUNDAY NIGHT INTO MONDAY, MID TO HIGH CHANCE POPS
(40-50%) WILL BE MAINTAINED AS CENTRAL CONUS THETA-E RIDGE SHIFTS
ACROSS THE REGION. SOME UNCERTAINTY STILL EXISTS WITH SHOWER CHANCES
DURING THIS PERIOD DUE TO LIKELIHOOD STRONGER FORCING WILL BE
DISPLACED NORTHWEST/NORTH OF THE LOCAL AREA.
FOR NEXT WEEK, MEDIUM RANGE GUIDANCE IS IN DECENT AGREEMENT THAT
SPLIT FLOW ACROSS EASTERN PACIFIC WILL YIELD A STRONGER SOUTHERN
STREAM UPPER TROUGH WHICH WILL EVENTUALLY REACH CENTRAL CONUS BY
NEXT WEDNESDAY. CONFIDENCE REMAINS HIGH IN MUCH ABOVE NORMAL
TEMPERATURES CONTINUING INTO TUESDAY WITH BROAD WARM SECTOR ACROSS
SOUTHERN GREAT LAKES/OHIO VALLEY. WEAKER EMBEDDED SHORT WAVES ARE
POSSIBLE EARLY NEXT WEEK IN STRONGER WESTERLY FLOW REGIME THAT COULD
INDUCE PERIODIC SHOWER/STORM CHANCES CONSIDERING SOME STEEPENING OF
MID LEVEL LAPSE RATES ANTICIPATED DURING THIS PERIOD. PRESENT
INDICATIONS WOULD SUGGEST PERHAPS BEST CHANCES OF MORE ORGANIZED
CONVECTIVE CHANCE BY MIDDLE OF NEXT WEEK WHEN THE WESTERN CONUS
UPPER TROUGH EJECTS NORTHEAST. HOWEVER, RECENT TREND IN ENSEMBLE
GUIDANCE POINTS TOWARD DOWNSTREAM UPPER RIDGING POTENTIALLY HOLDING
STRONGER ACROSS EASTERN THIRD OF THE COUNTRY INTO MIDDLE OF NEXT
WEEK WHICH COULD ALLOW FOR SOME DAMPENING OF THIS UPPER TROUGH
ACROSS THE GREAT LAKES REGION. / MARSILI
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 653 PM EDT THU APR 9 2026
A WEAK FRONT WAS OVER NORTHERN INDIANA WITH SHOWERS DEVELOPING
IN THE COOLER AIR ON THE NORTHERN SIDE OF THE FRONT. A SERIES OF
IMPULSES WILL RACE EAST WITH THE UPPER FLOW. THESE IMPULSES WILL
BRING SHOWERS AND SCATTERED THUNDERSTORMS TO NORTHERN INDIANA THROUGH
FRIDAY. ALONG WITH THE SHOWERS AND STORMS, WIND SHEAR IS EXPECTED
TONIGHT. LOW LEVELS WILL SATURATE TONIGHT, ESPECIALLY AT SBN
WHERE IFR CEILINGS ARE EXPECTED BY LATE TONIGHT. SURFACE HIGH
PRESSURE OVER THE UPPER MIDWEST WILL BUILD INTO THE REGION AND
HELP CLEAR OUT THE LOWER LAYERS AT SBN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...HAMMER
AVIATION...SKIPPER
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