499
FXUS63 KIWX 042043
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
343 PM EST TUE NOV 4 2025
KEY MESSAGES
- WINDY CONDITIONS AND MILD FOR WEDNESDAY, BUT TEMPERATURES BEGIN
FALLING WEDNESDAY AFTERNOON.
- RAIN SHOWERS LIKELY LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
AFTERNOON. AN ISOLATED THUNDERSTORM POSSIBLE.
- ANOTHER SYSTEM BRINGS A LIKELIHOOD OF RAIN (POSSIBLY WITH SOME SNOW
MIXING IN) LATER SATURDAY INTO SUNDAY. CONFIDENCE IN PRECIP
TYPES STILL REMAINS ON THE LOW SIDE GIVEN UNCERTAINTY IN
TRACK.
- CHANCES OF LAKE EFFECT SNOW SHOWERS INCREASE SOME TIME IN THE
LATER SUNDAY/MONDAY TIMEFRAME.
DISCUSSION
ISSUED AT 334 PM EST TUE NOV 4 2025
DEPARTING LOW LEVEL RIDGE AXIS WILL ALLOW FOR WARM/MOIST
ADVECTION FROM SOUTHWEST TO NORTHEAST THIS EVENING. A BROAD, LOW
AMPLITUDE UPPER LEVEL TROUGH ACROSS THE NORTHERN PLAINS WILL
AUGMENT THIS ADVECTION AS LOW LEVEL FLOW STRENGTHENS THIS
EVENING FROM THE SOUTHERN PLAINS INTO THE SOUTHERN GREAT LAKES.
THE STRONGEST LOW LEVEL BAROCLINICITY AND ISENTROPIC UPGLIDE
AND ASSOCIATED PRECIP POTENTIAL SHOULD REMAIN WELL NORTH OF THE
LOCAL AREA TONIGHT ACROSS THE NORTHERN GREAT LAKES REGION. THIS
ADVECTIVE REGIME SHOULD INDUCE BROAD, STRONG SFC PRESSURE FALLS
ACROSS THE GREAT LAKES WHICH SHOULD HELP TO AUGMENT SOUTHERLY
LOW LEVEL FLOW ACROSS THE LOCAL AREA. AFTER A POSSIBLE LULL IN
WINDS IN EARLY EVENING, AN UPTICK IN SPEEDS IN SFC WIND GUSTS IS
EXPECTED LATE EVENING AND OVERNIGHT THAT SHOULD RESULT IN NON-
TYPICAL DIURNAL TREND OF STEADY/SLOWLY RISING TEMPERATURES
DURING THE OVERNIGHT HOURS.
LOW LEVEL FRONTAL ZONE WILL BEGIN TO SAG SOUTHEAST ACROSS THE UPPER
MIDWEST/UPPER MS VALLEY WITH SOME LOW/MID LEVEL FGEN FORCING
INCREASING. HOWEVER, OVERALL LOW LEVEL MOISTURE QUALITY APPEARS TO
BE LIMITED LEADING TO LOW CONFIDENCE IN ANY MEASURABLE PRECIP WITH
FRONTAL PASSAGE. ANY LOW END CHANCE OF MEASURABLE RAIN STILL
APPEARS TO BE ACROSS THE FAR NORTH/NORTHEAST WHICH SHOULD BE IN
CLOSER PROXIMITY TO GREATEST SYNOPTIC FORCING/UPPER JET
DYNAMICS.
THE BIG STORY ON WEDNESDAY WILL BE THE WINDS, AS PRE-FRONTAL
SOUTHWESTERLIES WILL INCREASE EARLY IN THE DAY FOLLOWED BY STRONG
WEST/NORTHWESTERLIES BEHIND THE FRONT AS MIXED LAYER DEEPENS. A
MODEST ISALLOBARIC CONTRIBUTION IS ALSO EXPECTED DURING THE
MIDDAY PERIOD WITH CYCLOGENESIS EXPECTED TO BE ONGOING AS THE
SFC REFLECTION TRACKS ACROSS THE EASTERN GREAT LAKES. GUSTS TO
AROUND 35 MPH APPEAR TO BE POSSIBLE FOR A TIME, ESPECIALLY LATE
MORNING INTO MID AFTERNOON. HIGHS LIKELY TO BE REACHED MIDDAY
FOR MANY AREAS ON WEDNESDAY AS STRENGTH OF COLD ADVECTION SHOULD
RESULT IN MORE OF A STEADY/SLOWLY FALLING TEMPERATURE TREND IN
THE AFTERNOON.
WINDS TO RELAX WEDNESDAY NIGHT INTO THURSDAY AS NEXT SFC
ANTICYCLONE OVERSPREADS THE AREA IN THIS PROGRESSIVE PATTERN.
THURSDAY COULD FEATURE SOMEWHAT SIMILAR CONDITIONS AS TODAY WITH
A VERY DRY LOW LEVEL AIR MASS IN PLACE AND AFTERNOON DEW POINTS
BACK INTO THE 20S AND LOW 30S. HOWEVER, LIGHTER WINDS ON
THURSDAY AND COOLER LOW LEVEL THERMAL PROFILES IN COMPARISON TO
TODAY SHOULD LIMIT FIRE WEATHER CONCERNS.
THE END OF THE WORK WEEK STILL FEATURES A MUCH GREATER CHANCE OF
RAIN AS A MORE SIGNIFICANT SHORT WAVE BREAKS OUT OF THE LARGE SCALE
EASTERN PACIFIC TROUGH. THIS SHORT WAVE WILL AT LEAST HAVE MORE OF
AN OPPORTUNITY FOR A PERIOD OF GOOD MOISTURE TRANSPORT NORTHWARD
INTO THE AREA (ALBEIT SOMEWHAT BRIEF). FORECAST SOUNDINGS STILL
SUGGEST SOME WEAK SFC BASED INSTABILITY ALSO POSSIBLE FRIDAY MORNING
INTO MID AFTERNOON AND HAVE MAINTAINED SLIGHT CHANCE OF THUNDER POPS.
THE PASSAGE OF THE FRIDAY SHORT WAVE SHOULD EFFECTIVELY CARVE OUT A
MORE SUPPRESSED TRACK FOR THE PRIMARY UPPER LEVEL EASTERN PACIFIC
WAVE ON FRIDAY INTO THE OHIO RIVER VALLEY. GUIDANCE CONSENSUS
CONTINUES TO FEATURE A STRONGER THERMAL RIBBON WITH THIS WAVE, AND
EVEN THE POTENTIAL OF SOME SNOW MIXING IN ON BACKSIDE OF THIS
SYSTEM. HOWEVER, LINGERING UNCERTAINTIES WITH TRACK AND MARGINAL LOW
LEVEL WET BULBS LEAD TO CONTINUED LOW CONFIDENCE IN PTYPE DETAILS.
CONFIDENCE REMAINS HIGHER IN A TREND TO MUCH COLDER CONDITIONS 2ND
HALF OF THE WEEKEND INTO EARLY NEXT WEEK, AND BASED ON MAGNITUDE OF
LOW LEVEL THERMAL PROGS, LAKE EFFECT RAIN/SNOW SHOWERS STILL APPEAR
QUITE POSSIBLE. HOWEVER, AT THIS FORECAST DISTANCE, A GOOD DEAL OF
UNCERTAINTY REMAINS IN FETCH DETAILS AND LONGEVITY OF THIS SETUP SO
HAVE NOT DEVIATED FROM CHANCE SNOW SHOWER MENTION SUNDAY
NIGHT/MONDAY.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1248 PM EST TUE NOV 4 2025
VFR CONDITIONS WILL CONTINUE THIS PERIOD, WITH WINDY CONDITIONS
AND LOW LEVEL WIND SHEAR AS THE PRIMARY AVIATION WEATHER
CONCERNS. LOW LEVEL RIDGE AXIS WILL CONTINUE TO SHIFT OFF TO THE
EAST THIS AFTERNOON ALLOWING FOR RETURN SOUTHERLY FLOW. A BROAD
LOW AMPLITUDE UPPER TROUGH SWINGING ACROSS THE NORTHERN PLAINS
INTO THIS EVENING WILL INDUCE STRENGTHENING WARM/MOIST ADVECTION
TONIGHT. STRONG SFC PRESSURE FALLS ARE EXPECTED TO DEVELOP
ACROSS THE GREAT LAKES REGION IN RESPONSE, WHICH SHOULD ENHANCE
SOUTHERLY LOW LEVEL FLOW. PREVIOUS TAF MENTION OF LLWS MENTION
HAS BEEN MAINTAINED WITH THE 18Z TAFS, WITH SOME SFC GUSTS TO
AROUND 20 KNOTS POSSIBLE LATE EVENING AND OVERNIGHT AS THE LOW
LEVEL JET STRENGTHENS. A STRONG PRE-FRONTAL PRESSURE GRADIENT
FOLLOWED BY DEEPENING MIXED LAYER IN POST-FRONTAL COLD ADVECTION
WILL SET THE STAGE FOR WINDY CONDITIONS WEDNESDAY, WITH PEAK
GUSTS EXPECTED FROM THE WEST-NORTHEAST MIDDAY INTO MID AFTERNOON
TO AROUND 30-35 KNOTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 AM EST
THURSDAY FOR LMZ043-046.
DISCUSSION...MARSILI
AVIATION...MARSILI
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