665
FXUS63 KIWX 241831
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
231 PM EDT WED APR 24 2024
KEY MESSAGES
-PERIOD OF NEAR/BELOW FREEZING TEMPERATURES EXPECTED EARLY
THURSDAY MORNING.
-TURNING MUCH WARMER THROUGH THE REMAINDER OF THE PERIOD.
-A FEW CHANCES FOR SHOWERS AND THUNDERSTORMS RETURN BY FRIDAY
NIGHT AND LINGER INTO MONDAY.
DISCUSSION
ISSUED AT 230 PM EDT WED APR 24 2024
INITIAL FOCUS REMAINS ON THREAT FOR FROST DEVELOPMENT AND RISK FOR A
PERIOD OF FREEZING TEMPERATURES. CLOUDS HAVE STUCK AROUND MUCH OF
THE DAY AS ANTICIPATED, WITH THE BACK EDGE OF THE STRATUS WORKING
SOUTH ACROSS LOWER MICHIGAN. WHILE MODELS SEEM TO AGREE ON THIS BACK
EDGE WORKING INTO THE AREA THIS EVENING, THE OVERALL FLOW BEGINS TO
WEAKEN WITH AN AREA OF HIGHER 850 MB RH LINGERING IN PARTS OF THE
AREA THROUGH 6Z AND POSSIBLE STALLING OVER THE SOUTHERN AREAS
OVERNIGHT.
TEMPERATURES WILL REBOUND NICELY THURSDAY AFTER THE FROSTY START AS
HIGH PRESSURE BUILDS ACROSS THE AREA WITH PLENTY OF SUNSHINE AND
LIGHT WINDS ALLOWING FOR HIGHS WELL INTO THE 50S (FEW 60S WEST).
LOWS THURSDAY NIGHT COULD DIP INTO THE MID 30S IN NE AREAS THAT
COULD WARRANT A FROST ADVISORY, BUT WILL LEAVE THAT FOR LATER
FORECASTS.
REMAINDER OF THE FORECAST WILL FOCUS ON 2 UPPER LOWS THAT EJECT FROM
THE SOUTHWESTERN STATES NORTHEAST IN TO THE PLAINS, NEVER QUITE
REACHING THE REGION. THE UPPER LEVEL PATTERN WILL HELP US WARM
DRAMATICALLY WITH AN INCREASE IN LOW LEVEL MOISTURE AS WELL, BUT
STILL LEAVES SOME BIGGER QUESTIONS AS TO TIMING, COVERAGE AND
INTENSITY OF A FEW ROUNDS OF PRECIPITATION. PRONOUNCED 850 MB THETA
E NOSE SCREAMS NORTHEAST ACROSS THE AREA FRIDAY, BUT LOW LEVELS WILL
REMAIN RATHER DRY AND BEST FORCING/INSTABILITY LIKELY TO REMAIN WELL
WEST OF THE REGION CLOSER TO THE UPPER LEVEL DYNAMICS. MODELS ARE
ABOUT SPLIT ON BAND OF RAIN ON THE WARM FRONT FRI NIGHT VS EITHER
CONFINING TO FAR NW AREAS OR EVERYTHING DISSIPATING THROUGH THE
EVENING. WILL MAINTAIN HIGHER POPS, BUT FEEL THEY MOST LIKELY WILL
NEED LOWERING AS WE GET CLOSER TO THE EVENT.
2ND WAVE WILL PROGRESS A TOUCH FURTHER EAST BUT STILL REMAIN WELL
REMOVED FROM THE AREA. A COLD FRONT WILL PUSH EAST IN THE SUNDAY
NIGHT TO MONDAY TIME FRAME FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS. RISK FOR HEAVY RAIN AND SEVERE WEATHER REMAINS
QUESTIONABLE AT THIS STAGE WITH BEST THREAT LIKELY TO PERSIST WEST OF
THE AREA.
TEMPS WILL COOL SOMEWHAT BEHIND THE FRONT TO END THE PERIOD, BUT
WITH NO STRONG PUSH OF COLD AIR AS ANY NORTHERN STREAM ENERGY
REMAINS WELL NORTH INTO CANADA ABOVE NORMAL CONDITIONS WILL
PERSIST.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1235 PM EDT WED APR 24 2024
IMPROVEMENT TREND TO CIGS WILL CONTINUE THROUGH THE REMAINDER OF
THE AFTERNOON/EARLY EVENING. COLD/DRY AIR ADVECTION WILL ALLOW
FOR SOME INCREASE IN CONVECTIVE LAYER DEPTHS THROUGH THE
REMAINDER OF THE AFTERNOON WHICH SHOULD TAKE CIGS TO AT OR ABOVE
3000 FEET AS WE HEAD TOWARD THE MID TO LATE AFTERNOON HOURS. AS
THE CONVECTIVE DEPTHS INCREASES, LOW LEVEL FLOW WILL CONTINUE TO
WEAKEN WHICH SHOULD LIMIT PREVAILING SPEEDS TO AROUND 10 KNOTS.
A BROAD RIDGE OF HIGH PRESSURE SETTING ACROSS THE GREAT LAKES
WILL PROVIDE LIGHT EAST-NORTHEAST WINDS TONIGHT, VEERING TO THE
EAST-SOUTHEAST FOR THURSDAY. VFR CONDITIONS ARE EXPECTED THROUGH
THE PERIOD ONCE THE CURRENT MVFR CIGS DIMINISH LATER THIS
AFTERNOON OR EARLY EVENING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FREEZE WARNING FROM 1 AM TO 9 AM EDT THURSDAY FOR INZ005>009-
018-027.
FROST ADVISORY FROM 1 AM EDT /MIDNIGHT CDT/ TO 9 AM EDT /8 AM
CDT/ THURSDAY FOR INZ012>015-017-020-022>026-032>034-103-
104-116-203-204-216.
OH...FREEZE WARNING FROM 1 AM TO 9 AM EDT THURSDAY FOR OHZ001-002-
004-005-015-016-024-025.
MI...FREEZE WARNING FROM 1 AM TO 9 AM EDT THURSDAY FOR MIZ078>081.
FROST ADVISORY FROM 1 AM TO 9 AM EDT THURSDAY FOR MIZ177-277.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ043-
046.
DISCUSSION...FISHER
AVIATION...MARSILI
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