201
FXUS63 KIWX 250536
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
136 AM EDT FRI SEP 25 2026
KEY MESSAGES
- TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL THROUGH THE
WEEKEND WITH THE COOLEST CONDITIONS EXPECTED TODAY.
TEMPERATURES WILL MODERATE EARLY NEXT WEEK TO NEAR NORMAL.
- AN EXTENDED PERIOD OF DRY WEATHER IS EXPECTED THROUGH
TUESDAY, WITH NEXT RAIN CHANCES NOT UNTIL THE MIDDLE OF NEXT
WEEK.
DISCUSSION
ISSUED AT 131 AM EDT FRI SEP 25 2026
THE ENERGY FROM THE EARLY WEEK RAINFALL DEEPENS OFF THE EAST COAST
TODAY. MEANWHILE, HEIGHT FALLS ENSUE AMONG THE MID LEVEL RIDGING
OVERHEAD AS A SHORTWAVE SHIFTS SOUTHWARD THROUGH LOWER MICHIGAN.
GIVEN HOW DRY WE'VE GOTTEN, NO PRECIPITATION IS EXPECTED FROM THE
WAVE. GRADIENT WINDS WEAKEN AS THE LOW LEVEL JET REGROUPS OVER THE
EAST COAST. THIS ALLOWS FOR LIGHT WINDS AS WELL. SUBSIDENCE TAKES
OVER BEHIND THE WAVE AND DRY AIR CONTINUES TO REMAIN ACROSS THE
AREA. GIVEN A SORT OF REX BLOCK TO OUR EAST ALONG THE EAST COAST,
DRY WEATHER IS EXPECTED TO PREVAIL TODAY INTO EARLY NEXT WEEK. AS A
VORTICITY STREAMER IN THE CENTRAL US RUNS INTO THE BLOCK, IT SHEARS
OUT AND DAMPENS DURING THE WEEKEND INTO EARLY THE NEXT WORK WEEK,
FURTHER INDICATING THE STRENGTH OF THE BLOCK. THE LOW LOW LEVEL
THETA-E AIRMASS SLOWLY INCREASES BETWEEN TODAY AND EARLY NEXT WEEK
INDICATING THAT TEMPERATURES WILL BE SLOWLY RISING AFTER TODAY.
HIGHS IN THE UPPER 60S TODAY, SURPASS 70F ON SATURDAY AND HAVE A
40+% CHANCE OF ACHIEVING 75F SOUTH OF US-30 STARTING MONDAY.
LOWS IN THE 40S ARE ALSO EXPECTED TO CONTINUE UNTIL WE GET TO
TUESDAY NIGHT.
WARM ADVECTION FINALLY BEGINS TO ENSUE LATER TUESDAY INTO TUESDAY
NIGHT. THE GREATEST CHANCE OF ACHIEVING 75F IS ON TUESDAY AS A
RESULT. HOWEVER, THIS IS STILL WHEN MEDIUM RANGE MODELS DIFFER ON
HOW MUCH MOISTURE TO BRING INTO THE AREA AND, THEREFORE HOW WARM IT
GETS STILL COMES WITH SOME UNCERTAINTY. THIS ONLY MUDDIES THE
THUNDERSTORM CHANCE PICTURE FROM THAT LATE TUESDAY TIME INTO
WEDNESDAY BEFORE CHANCES RELOAD FOR FRIDAY AND THE WEEKEND.
TUESDAY'S CHANCE COMES AS A DIFFUSE AREA OF VORTICITY PUSHES
EASTWARD IN ASSOCIATION WITH A COLD FRONT. THE WAVE IS RATHER FLAT
AND MUCH BETTER FORCING IS FARTHER NORTH. THE FORCING FOR LATE WEEK
TO POSSIBLY THE WEEKEND IS A CUTOFF LOW IN THE SOUTHWEST THAT GETS
PULLED NORTHWARD IN THE NEXT TROUGH. THE ECMWF IS NOTORIOUS FOR
LEAVING THESE WAVES IN THE SOUTHWEST TOO LONG, BUT THE GFS IS
NOTORIOUS FOR MOVING SYSTEMS TOO FAST. THE ANSWER MAY LIE
SOMEWHERE IN BETWEEN.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 131 AM EDT FRI SEP 25 2026
AFTER OUR CLOUDINESS HAS DEPARTED, THERE IS SOME LINGERING MOISTURE
IN THE SOIL AND AREAS WHERE SUNSHINE OCCURRED BEFORE SUNSET COULD
HAVE SOME FOG AROUND. NAM BUFKIT SOUNDINGS INDICATE AT LEAST GROUND
FOG, CROSS-OVER TEMPS SEEM FAVORABLE FOR IT, AND WINDS DIE DOWN
OVERNIGHT. ONE ISSUE MAY BE THAT HIGH CLOUDS COULD PREVENT
RADIATIONAL COOLING. PERHAPS THAT'S WHY THERE AREN'T MORE AVIATION
GUIDANCE SOLUTIONS WITH DENSER FOG AROUND. STILL NOT QUITE READY TO
TAKE FOG OFF THE TABLE YET. OTHERWISE, NORTHEAST WINDS CONTINUE, BUT
STAY LESS THAN 10 KTS SUSTAINED WITH MINIMAL GUSTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...ROLLER
AVIATION...ROLLER
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