878
FXUS63 KIWX 181735
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
135 PM EDT WED MAR 18 2026
KEY MESSAGES
- SERIES OF FAST MOVING WAVES TO BRING TWO PERIODS OF LIGHT
PRECIPITATION THROUGH THURSDAY.
- TRENDING BACK TO ABOVE NORMAL STARTING THURSDAY WITH THE
WARMEST TEMPS COMING FRI-SAT.
- COLD FRONT ARRIVES SUNDAY WITH CHANCES FOR SHOWERS (MAYBE A
FEW STORMS) FOLLOWED BY A RETURN TO MORE SEASONABLE TEMPS TO
START THE WORK WEEK.
DISCUSSION
ISSUED AT 242 AM EDT WED MAR 18 2026
OVERALL NW FLOW ALOFT WILL CONTINUE TO SEND RELATIVELY WEAK
CLIPPERS/DISTURBANCES INTO THE REGION OVER THE NEXT COUPLE OF DAYS
BEFORE UPPER LEVEL HEIGHTS INCREASE SUFFICIENTLY TO ALLOW A TEMPORARY
SHIFT NE OF THIS ACTIVE FLOW. THE IMPACTS OF THE FIRST WAVE ARE
ALREADY BRINGING SOME LIGHT SNOW TO PORTIONS OF SW WI/NE IA AND NE
MN WITH VSBYS GENERALLY ABOVE A MILE. AS THE ISENTROPIC LIFT
INCREASES OVER THE NEXT SEVERAL HOURS, A LOT OF DRY AIR NEEDS TO BE
OVERCOME (00Z KILX SOUNDING SHOWED A VERY DRY LAYER BETWEEN 700 AND
900 MB) BEFORE ANY SNOW CAN REACH THE GROUND. HAVE MADE SOME CHANGES
WRT TIMING AND OVERALL POPS, WHICH MAY NEED FURTHER REVISION IN THE
COMING HOURS AS WE SEE HOW THIS UNFOLDS. OVERALL SNOW ACCUMULATIONS
WILL BE UNDER AN INCH AND MOST LIKELY NEAR/UNDER A HALF INCH
(HIGHEST WEST), WHICH COULD CAUSE SOME SLICK SPOTS FOR THE MORNING
COMMUTE. ANY PRECIP QUICKLY EXITS BY AFTERNOON WITH TEMPS CLIMBING
ABOVE FREEZING (40S SW).
NEXT, SOMEWHAT STRONGER, WAVE DIVES SE LATE WED NIGHT INTO THURSDAY
WITH ANOTHER BURST OF ISENTROPIC LIFT. TRENDS SUGGEST ONSET LIKELY
NOT OCCURRING UNTIL AFTER 9Z AND POSSIBLY EVEN CLOSER TO 12Z THU.
EXACT ONSET TIME MAY FACTOR INTO PTYPE WITH AIR TEMPS LIKELY NEAR
FREEZING IN NE AREAS. FOR NOW HAVE REMOVED ANY ZR MENTION AND IF
SOME OCCURRED, IT WOULD BE VERY BRIEF IN DURATION AS WAA STRENGTHENS
ACROSS THE AREA. OVERALL QPF WILL BE SOMEWHAT HIGHER THAN TODAY'S
SYSTEM, MAYBE REACHING A TENTH OR SO IN SOME AREAS.
MORE SUBSTANTIAL LOW LEVEL WAA COMMENCES GOING INTO FRI AND SAT WITH
HIGHS BACK INTO THE 60S AND POSSIBLY SOME 70S AS THE MAIN TRAIN OF
WAVES IS PUSHED NE (FOR A SHORT PERIOD). A STRONGER COLD FRONT
ARRIVES LATE SAT NIGHT INTO SUNDAY, BUT SO FAR APPEARS TO BE LACKING
DEEPER MOISTURE (SFC DEWPOINTS STRUGGLE TO 50 DEGREES SAT NIGHT)
RESULTING OF LOWER OVERALL QPF POTENTIAL. IN THE WAKE OF THE FRONT,
MORE SEASONABLE TEMPERATURES START THE WORK WEEK WITH SOME MODERATION
BACK ABOVE NORMAL TO END THE PERIOD.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 123 PM EDT WED MAR 18 2026
IN THE WAKE OF THE EXITING CLIPPER SYSTEM MVFR CIGS WILL IMPROVE
TO VFR CATS. TOWARDS THE END OF THIS TAF PERIOD CHANCES OF SOME
LIGHT RAIN SHOWERS WILL BE POSSIBLE HOWEVER WITH THE HIGHER CIGS
AND LOWER DEW POINTS WILL HAVE A HARDER TIME MAKING IT TO THE
SURFACE AT LEAST INITIALLY BEFORE THE LOWER LEVELS MOISTEN AHEAD
OF THE RIDGING PUSHING INTO THE REGION. WINDS WILL REMAIN LIGHT
THROUGH THIS TAF PERIOD.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...FISHER
AVIATION...ANDERSEN
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