067
FXUS63 KIWX 280531
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
131 AM EDT FRI MAR 28 2025
KEY MESSAGES
- MILD OVERNIGHT WITH AN INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS PRIOR TO DAYBREAK.
- DRYING OUT FRIDAY AFTERNOON BUT BECOMING BREEZY WITH SOUTHWEST
GUSTS UP TO 40 MPH.
- WARM BUT RAINY WEEKEND WITH A CHANCE OF THUNDERSTORMS AS WELL.
DISCUSSION
ISSUED AT 240 PM EDT THU MAR 27 2025
CYCLOGENESIS IS UNDERWAY OVER THE CENTRAL PLAINS THIS AFTERNOON. IN
THE WARM SECTOR, EXTENDING INTO FAR WESTERN IL, CONVECTION IS
UNDERWAY AND IS ANTICIPATED TO BECOME REINVIGORATED OVERNIGHT. THIS
BOOST IS COURTESY OF A BLOSSOMING 60-KNOT 850-MB JET. WHILE THE
PRIMARY INSTABILITY POOL WILL RESIDE OVER IOWA AND WESTERN ILLINOIS,
A BROAD CORRIDOR OF 500 J/KG IS NOTED ON THE 12Z HREF PRIMARILY WEST
OF I-69 OVERNIGHT. SEVERE WEATHER IS NOT ANTICIPATED, THOUGH PEA
SIZED HAIL CANNOT BE RULED OUT AS OBSERVED EARLIER TODAY ALONG THE
ILX-LOT FORECAST BORDER.
AS THE NOSE OF THIS JET MOVES EAST, COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL DIMINISH THROUGH FRIDAY MORNING. THERE WILL BE A
BRIEF PERIOD OF GUSTY SOUTHWEST WIND (35 TO 40 MPH) IN THE AFTERNOON
AS CLOUD COVER DECREASES AND WE MIX-DOWN STRONG LOW-LEVEL WINDS. THE
HREF INDICATES ONLY A 10% TO 20% CHANCE OF WIND GUSTS GREATER THAN
45 MPH FRIDAY AFTERNOON.
BY SATURDAY MORNING, A LARGE PORTION OF OUR AREA COULD BE SPLIT BY
1) RAIN TO THE NORTH OVER CENTRAL MICHIGAN (DRIVEN BY FRIDAY'S WARM
FRONT NOW RELOCATED) AND 2) RENEWED MOISTURE ADVECTION TO OUR SOUTH
ACROSS CENTRAL IN. LOW PRESSURE EMERGING FROM THE ROCKIES OPPOSES AN
OFFSHORE SOUTHEAST US RIDGE RESULTING IN A STEADY DOSE OF MOISTURE
TRANSPORT. THERE WILL BE SOME DRY HOURS SATURDAY, ESPECIALLY ALONG
THE NORTH OF THE US 30 CORRIDOR. HOWEVER, BROAD CHANCE POPS REMAIN
IN THE ABSENCE OF HIGH RESOLUTION GUIDANCE AT THIS TIME. THUNDER
APPEARS UNLIKELY SATURDAY OWING TO A LACK OF INSTABILITY. OVERNIGHT,
RAIN LIFTS INTO NORTHWEST OHIO. RAIN IS PERHAPS MOST WIDESPREAD
SUNDAY AS THE LOW MOVES ACROSS SOUTHERN LAKE MICHIGAN. MEAGER
INSTABILITY RETURNS AS WELL BRINGING THUNDER BACK TO THE FORECAST.
PAIRED WITH ABOUT 30 KNOTS OF SHEAR, I IMAGINE AT LEAST A SLIVER OF
OUR FORECAST AREA WILL REMAIN IN A CONVECTIVE OUTLOOK BY THE STORM
PREDICTION CENTER. HOWEVER, KNOW THAT THE OVERALL SEVERE WEATHER
RISK APPEARS LOW FOR OUR LOCAL AREA.
SHARPLY COLDER SUNDAY NIGHT AND MONDAY WHEN HIGHS WILL ONLY BE IN
THE 40S (COMPARED TO 70S FRIDAY THROUGH SUNDAY). MILDER BY MIDWEEK
AS ZONAL FLOW RESUMES. AFTER MONDAY MORNING, THE NEXT CHANCE FOR
WIDESPREAD RAIN IS WEDNESDAY.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 124 AM EDT FRI MAR 28 2025
CONFIDENCE IN OVERALL IMPACTS AT BOTH SITES OVER THE NEXT 6 TO 9
HOURS VARIES IN SEVERAL ASPECTS. HI RES MODELS HAVE SIGNALED AT
SCATTERED SHOWER DEVELOPMENT TAKING SHAPE IN THE 4 TO 6Z TIME
FRAMED AND RADAR RETURNS IN NE IL INTO NW IN DO INDEED REFLECT
THIS ON THE LEADING EDGE OF INCREASING THETA-E. THIS RESULTS IN
HIGHER CONFIDENCE OF SHOWERS IMPACTING BOTH SITES OVERNIGHT INTO
FRIDAY MORNING. COVERAGE AND IMPACTS ON CIGS AND VSBY WOULD
SEEM TO BE MORE LIMITED IN TIME, TIED TO EACH SHOWER WITH
IMPROVEMENT IN BETWEEN. THIS IS WHERE THE LOWER CONFIDENCE
BEGINS TO SET UP WITH EVEN LOWER CONFIDENCE ON POSSIBLE THUNDER
CHANCES AS STEEPER LAPSE RATES ARRIVE FOR A SMALL WINDOW. HAVE
TRIED TO LIMIT THUNDER POTENTIAL AS BEST AS POSSIBLE BUT WILL
NEED TO MONITOR TRENDS AT BOTH SITES. WARM FRONT WILL SURGE
NORTH DURING THE MORNING WITH KFWA SEEING IMPROVING CONDITIONS
FIRST. KSBN COULD REMAIN IN SOME SHOWER (MAYBE STORM) ACTIVITY
THROUGH PARTS OF THE MORNING AS THE FRONT STALLS SOMEWHAT BEFORE
GETTING A STRONGER PUSH NORTH.
ONCE CIGS IMPROVE TO VFR AND WE ENTER THE WARM SECTOR, CONCERN
SHIFTS TO GUSTY WINDS BEING MIXED DOWN (ON THE ORDER OF 25 KTS
OR SO).
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 4 AM EDT
SATURDAY FOR LMZ043-046.
DISCUSSION...BROWN
AVIATION...FISHER
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