732
FXUS63 KIWX 221723
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
123 PM EDT TUE APR 22 2025
KEY MESSAGES
- INCREASING CLOUDS THIS AFTERNOON AND HIGH TEMPERATURES NEAR
70.
- SHOWERS AND THUNDERSTORMS THIS EVENING AND OVERNIGHT,
PRIMARILY NORTHWEST OF US 24.
- VERY WARM WEDNESDAY THROUGH FRIDAY WITH HIGHS IN THE LOW-80S
THURSDAY FOLLOWED BY SHOWERS AND STORMS FRIDAY.
DISCUSSION
ISSUED AT 314 AM EDT TUE APR 22 2025
WATER VAPOR THIS MORNING SHOWS AN UPPER-LEVEL LOW LIFTING THROUGH
MN, WITH A SUBTLE BAROCLINIC ZONE INFERRED TO ITS SOUTH, SPREADING
THROUGH THE CENTRAL PLAINS. CONVERGENCE IS NOTED IN THE SURFACE
OBSERVATIONS AND THIS BAROCLINIC ZONE WILL BE THE FORCING MECHANISM
FOR SHOWERS AND THUNDERSTORMS PRIMARILY NORTHWEST OF US 24 THIS
EVENING AND OVERNIGHT. GUIDANCE HAS COME NOTABLY FARTHER SOUTH WITH
RAIN CHANCES SINCE 12 HOURS AGO OWING TO A SEEMINGLY FLATTER, ZONAL
500-MB PATTERN.
HIGH PRESSURE CURRENTLY OVERHEAD LEAVES BEHIND A STOUT DRY LAYER
THAT IS FORECAST TO BE CONQUERED AFTER 00Z (8PM EDT) WHEN IMPROVED
FORCING ARRIVES VIA A MODEST 850-MB JET. INSTABILITY IS GENERALLY
FORECAST TO BE NEAR 500 J/KG RESULTING IN A NON-ZERO CHANCE FOR
THUNDER. HOW FAR SOUTH AND EAST SHOWERS AND STORMS PROGRESS IS
UNCERTAIN. HIGH PRESSURE LINGERS ACROSS NORTHWEST OHIO AND CENTRAL
INDIANA WHICH WILL CERTAINLY WORK AGAINST WET WEATHER THERE. AN
OVERALL LACK OF STRONG FORCING PERMITS THIS HIGH TO LOITER RATHER
THAN EXIT OVER THE EAST COAST. THIS BAROCLINIC ZONE REMAINS INTO
WEDNESDAY MORNING AS WELL, NECESSITATING SLIGHT CHANCE (20%) POPS.
NOT A WASHOUT TO END THE WEEK BUT THERE ARE SEVERAL CHANCES FOR
SHOWERS AND THUNDERSTORMS. A SOUTHEAST US RIDGE PUMPS IN ADEQUATE
GULF MOISTURE WHILE BROAD TROUGHING IN THE WEST SENDS SHORTWAVES
THROUGH THE FOUR CORNERS AND INTO THE NATION'S HEARTLAND. WET
WEATHER WILL BE MOST WIDESPREAD FRIDAY AS LOW PRESSURE MOVES
OVERHEAD. COOLER IN ITS WAKE AS CANADIAN HIGH PRESSURE LIMITS HIGHS
ON SATURDAY TO THE LOW-TO-MID 60S. THIS IS A NOTABLE CONTRAST TO
HIGHS WEDNESDAY THROUGH FRIDAY WHICH WILL BE WELL INTO THE 70S TO
NEAR 80.
BECOMING VERY WARM ONCE MORE IN THE FINAL DAYS OF APRIL WITH MORE
WET WEATHER AS THE SOUTHEAST US RIDGE AMPLIFIES FURTHER, STEERING
ADDITIONAL IMPULSES OVERHEAD.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 122 PM EDT TUE APR 22 2025
WILL CONTINUE WITH PREVAILING VFR CONDITIONS, ESPECIALLY FOR FWA.
SBN HAS A POTENTIAL FOR RAIN TO CREEP IN ESPECIALLY AFTER MIDNIGHT
TONIGHT WHEN THE DEW POINT DEPRESSIONS FINALLY CREEP LOW ENOUGH.
WILL CONTINUE TO GO WITH PREVAILING VFR THERE THOUGH WITH LOW
CONFIDENCE OF FLIGHT CONDITION-IMPACTFUL LOW LEVEL MOISTURE THAT
FAR OUT. OTHERWISE, WINDS ARE GENERALLY SOUTH-SOUTHWEST THROUGH
THE PERIOD WITH GUSTS KEPT AT A MINIMUM OF OCCURRENCES.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...ROLLER
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