479
FXUS63 KIWX 290757
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
357 AM EDT SAT MAR 29 2025
KEY MESSAGES
- REMAINING BREEZY AND MILD TODAY WITH LOW CHANCES OF RAIN SHOWERS
(20-40%).
- RAIN SHOWER CHANCES INCREASE TONIGHT (50-70%) INTO SUNDAY MORNING.
- THERE REMAINS A RISK FOR SEVERE STORMS FROM MID AFTERNOON ON
SUNDAY THROUGH SUNDAY EVENING.
- BRIEF SHOT OF COOLER TEMPERATURES MONDAY INTO TUESDAY.
DISCUSSION
ISSUED AT 347 AM EDT SAT MAR 29 2025
THE POTENTIAL OF SEVERE WEATHER SUNDAY AFTERNOON INTO SUNDAY EVENING
REMAINS THE PRIMARY FORECAST CONCERN FOR THE SHORT TERM PERIOD.
IN THE NEAR TERM FOR TODAY, A POCKET OF MAINLY CLEAR SKIES PERSISTS
ACROSS NORTHERN INDIANA AND NORTHWEST OHIO THIS MORNING WITH
THE SOUTHERN GREAT LAKES REGION SITUATED BETWEEN MORE ACTIVE
FRONTAL BOUNDARY TO THE NORTH AND A SHORT WAVE TROUGH ACROSS THE
MID TO LOWER MS VALLEY. A POCKET OF DRIER LOW LEVEL AIR APPEARS
TO BE ROTATING THROUGH LARGER SCALE LOW LEVEL RIDGE ACROSS
SOUTHEAST CONUS WHICH SHOULD LIMIT RAIN CHANCES TODAY ALONG AND
SOUTH OF US 24 CORRIDOR ACROSS EXTREME NORTHEAST INDIANA INTO
NORTHWEST OHIO. BEST CHANCES OF SOME LIGHT RAIN SHOWERS APPEAR
TO BE ACROSS NORTHWEST INDIANA AS SOME RENEWED LOW/MID LEVEL
MOISTURE TRANSPORT DEVELOPS ONCE AGAIN. THIS MOISTURE TRANSPORT
IS IN RESPONSE TO A SOUTHWESTERLY LOW LEVEL JET DEVELOPING AS
UPSTREAM SHORT WAVE TROUGH GETS SHEARED TO THE NORTHEAST. ANY
SFC BASED INSTABILITY LOOKS TOO MEAGER FOR THUNDER INCLUSION AT
THIS TIME GIVEN THE LOSS OF THE STEEPER MID LEVEL LAPSE RATES
THAT WERE IN PLACE 24 HOURS AGO. IT WILL REMAIN BREEZY/WINDY AND
MILD TODAY WITH SOUTHWEST GUSTS INTO THE 25 TO 30 MPH RANGE.
RAIN CHANCES THIS EVENING REMAIN OF SOMEWHAT LOW CONFIDENCE. LARGE
SCALE MOISTURE TRANSPORT WOULD FAVOR RAMPING UP OF POPS THIS EVENING
WITH SOME SMALLER SCALE SHORT WAVES ALSO EXPECTED TO LIFT
NORTHEAST FROM THE LOWER OHIO VALLEY. BETTER CHANCES OF RAIN
SHOWERS BY MID-LATE EVENING MAY SHIFT EAST OF THE INTERSTATE 69
CORRIDOR AS THE BROAD LOW-MID LEVEL THETA-E GRADIENT BEGINS TO
PUSH EASTWARD. IT WILL REMAIN MILD TONIGHT WITH LOWS ONLY
EXPECTED TO DROP INTO THE MID-UPPER 50S.
THE POTENTIAL OF SEVERE WEATHER REMAINS IN PLACE FOR SUNDAY
AFTERNOON INTO SUNDAY EVENING. AN UPPER SPEED MAX WILL CONTINUE TO
MAKE ITS WAY ACROSS FOUR CORNERS REGION THIS MORNING AND WILL
EVENTUALLY HELP TO DEEPEN A MID/UPPER TROUGH ACROSS THE CENTRAL
PLAINS INTO THE CORN BELT BY MIDDAY SUNDAY. STRONG SOUTHERLY
LOW LEVEL FLOW HEAD OF THIS FEATURE WILL HELP TO ADVECT UPPER
50S/LOWER 60S INTO THE LOCAL AREA. AT THE SAME TIME, SOME
RENEWED STEEPENING MID LEVEL LAPSE RATES IS EXPECTED GIVEN
SOURCE REGION FOR THIS SHORT WAVE FROM THE CENTRAL/SOUTHERN
PLAINS. THE COMBINATION COULD SUPPORT A 750-1500 J/KG SBCAPE
AXIS TO SHIFT INTO NORTHWEST INDIANA EARLY SUNDAY AFTERNOON,
AND STRENGTHENING MID/UPPER FLOW WITH APPROACH OF THIS WAVE
SHOULD SUPPORT 40-50 KNOTS OF DEEP LAYER SHEAR. WHAT REMAINS
UNCERTAIN IS EXTENT OF INSTABILITY AS PRE-FRONTAL ENVIRONMENT
MAY BE CHARACTERIZED BY CLOUDS/SHOWERS POSSIBLY LIMITING
INSTABILITY. THIS STABILIZING EFFECT MAY BE PARTIALLY OFFSET BY
THE EML ADVECTING INTO THE AREA, SO STILL A GOOD DEAL OF
UNCERTAINTY IN HOW THINGS WILL EVOLVE.
STRONGLY FORCED NATURE OF SETUP BY EARLY-MID SUNDAY AFTERNOON AND A
60-70 KNOT 700 MB SPEED MAX NOSING INTO THE REGION MAY HELP INITIATE
CONVECTION ALONG PRE-FRONTAL TROUGH TYPE FEATURE ACROSS THE WEST
POSSIBLY IN THE FORM OF A BROKEN LINE OF CELLS. BACKGROUND SHEAR
WOULD SUPPORT SOME SUPERCELL STRUCTURE, AND IF A LINEAR FEATURE
FORMS, LINE NORMAL SHEAR OF AROUND 40 KNOTS COULD SUPPORT SOME
TYPE OF QLCS WIND/TORNADO THREAT WITH ANY DEVELOPMENT ALONG PRE-
FRONTAL FEATURE INTO THE EVENING. ALL CONVECTIVE MODES STILL
POSSIBLE GIVEN DEEP LAYER SHEAR PROFILES SUPPORTIVE OF
SUPERCELLS AND WHAT COULD BE DECENT ELONGATION OF LOW LEVEL
HODOGRAPHS GIVEN GOOD SPEED SHEAR BENEATH SUBTLE VEERING WIND
PROFILES. INSTABILITY REMAINS THE BIGGEST ITEM OF UNCERTAINTY
WHICH WILL DICTATE EXTENT OF SEVERE POTENTIAL. ONE CHANGE IN
FORECAST THINKING TODAY GIVEN WHAT APPEARS TO BE GOOD CAM
CONSENSUS, IS TO MOVE UP ONSET TIME OF SEVERE WEATHER POTENTIAL
TO THE MID AFTERNOON HOURS GIVEN THE ABOVE FACTORS. CONFIDENCE
IS A BIT LOWER HEADING INTO THE LATE EVENING AND EARLY OVERNIGHT
SUNDAY IN REGARDS TO EXTENT OF SEVERE POTENTIAL AND WHETHER
PRIMARY FOCUS MAY SHIFT SOUTH OF THE AREA WHERE INSTABILITY WILL
LIKELY BE MORE FAVORABLE BY THIS TIME. NO MAJOR CHANGES OF NOTE
WITH SPC DAY 2 CONVECTIVE OUTLOOK KEEPING AN ENHANCED RISK OF
SEVERE STORMS GENERALLY SOUTH OF US 6, AND A SLIGHT RISK OF
SEVERE STORMS TO THE NORTH ACROSS THE REMAINDER OF THE AREA INTO
SOUTHERN LOWER MICHIGAN.
MUCH COOLER CANDIDNESS BUILD IN FOR LATER SUNDAY NIGHT INTO
MONDAY WITH MAINLY DRY WEATHER EXPECTED MONDAY AFTERNOON THROUGH
TUESDAY EVENING.
THE NEXT SYSTEM THAT WILL NEED TO BE MONITORED IS FOR THE LATE
TUESDAY THROUGH WEDNESDAY NIGHT PERIOD AS MEDIUM RANGE GUIDANCE
CONTINUES TO INDICATE A VERY STRONG EASTERN PACIFIC JET CARVING OUT
AN IMPRESSIVE UPPER LEVEL SYSTEM ACROSS NORTH CENTRAL CONUS.
THIS SHOULD INDUCE A PERIOD OF VERY STRONG WARM/MOIST ADVECTION
ACROSS THE REGION THAT COULD ALLOW SFC DEWPOINTS TO RISE FROM
THE MID 20S TO LOWER 30S TUESDAY NIGHT, TO THE MID 50S TO AROUND
60 BY LATER WEDNESDAY. VERY STRONG KINEMATIC FIELDS WITH THIS
SYSTEM RAISE CONCERN FOR STRONG/SEVERE POTENTIAL, BUT
INSTABILITY MAGNITUDES COULD BE A LIMITING FACTOR AND WILL NEED
TO FURTHER ASSESS THIS POTENTIAL OVER NEXT SEVERAL FORECAST
CYCLES. ALONG WITH MODERATING TEMPERATURES INTO THE MIDDLE OF
THE WEEK WILL BE THE POTENTIAL OF SOME STRONG SYNOPTIC WINDS FOR
THE WED-THU PERIOD.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 142 AM EDT SAT MAR 29 2025
LL MOISTURE AND LIFT WILL SLOWLY INCREASE THROUGH THE PERIOD.
SOME LIGHT SHOWERS WERE NOTED UPSTREAM IN SW IL BUT ARE
STRUGGLING TO REACH THE GROUND WITH HIGH BASES STILL IN PLACE.
MODELS DEVELOP SOME SHOWERS (MAYBE A RUMBLE OF THUNDER THIS
AFTERNOON) BUT DON'T THINK COVERAGE OR IMPACTS WILL BE A MAJOR
CONCERN UNTIL MAYBE AFTER 00Z SUN AS MUCH DEEPER MOISTURE
ARRIVES WITH MVFR CIGS/VSBY POSSIBLE. MADE SOME ADJUSTMENTS
MAINLY TO TEMPER PRECIP IN THE FIRST 12 HOURS OR SO.
ALSO LOWERED LLWS SOMEWHAT AS PEAK WINDS WERE SLOWLY DIMINISHING
(KIWX VAD SHOWING 45 KTS AT 2KFT).
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
LMZ043-046.
DISCUSSION...MARSILI
AVIATION...FISHER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page