896
FXUS63 KIWX 150015
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
815 PM EDT WED OCT 14 2026
KEY MESSAGES
- COOLER CONDITIONS FOR TONIGHT WITH A BREAK IN THE GREATER RAIN
SHOWER COVERAGE EXPECTED INTO THURSDAY MORNING. MORE SHOWERS
AND THUNDERSTORMS ARE EXPECTED THURSDAY INTO THURSDAY NIGHT.
- THERE IS A MARGINAL RISK OF SEVERE STORMS (MAINLY WIND) ALONG
AND SOUTH OF US ROUTE 24 FOR THURSDAY EVENING. CONFIDENCE IN
SEVERE WEATHER IS LOW.
- TURNING MUCH COOLER AND WINDY FOR FRIDAY WITH SOME LAKE EFFECT
RAIN SHOWERS EXPECTED.
DISCUSSION
ISSUED AT 317 PM EDT WED OCT 14 2026
SURFACE COLD FRONTAL BOUNDARY HAS CLEARED SOUTHERN PORTIONS OF THE
FORECAST AREA THIS AFTERNOON. THE LOW LEVEL BAROCLINIC ZONE IS NOT
EXPECTED TO MAKE MUCH MORE ADDITIONAL SOUTHWARD PROGRESS INTO THIS
EVENING AS BROAD UPPER TROUGHING ACROSS SOUTHERN ONTARIO/GREAT
LAKES REGION PUSHES EAST ALLOWING SOME INDUCED SHORT WAVE UPPER
RIDGING TO BUILD INTO THE REGION DOWNSTREAM OF LARGER SCALE CUT-
OFF LOW. SOME ISOLATED SHOWERS ARE POSSIBLE THROUGH LATE
AFTERNOON/EARLY EVENING WITH WEAKENING FRONTAL ZONE ACROSS THE
SOUTH, BUT OTHERWISE PROSPECTS FOR ADDITIONAL RAINFALL TONIGHT
LOOK TO BE ON THE LOW SIDE GIVEN SOUTHWARD FRONTAL PUSH AND
BREAK IN STRONGER SHORT WAVE FORCING.
WATER VAPOR THIS IMAGERY THIS AFTERNOON DEPICTS TWO FEATURES
THAT WILL BE WATCHED OVER THE NEXT 48 HOURS INCLUDING A CUT-OFF
UPPER LEVEL LOW ACROSS SW CO AND A MORE PROGRESSIVE VORT MAX
SPILLING DOWN EASTERN SIDE OF WESTERN CANADIAN UPPER TROUGH.
PRESENT INDICATIONS STILL SUGGEST A PHASING OF THESE FEATURES
THURSDAY EVENING ACROSS THE CORN BELT AND UPPER MIDWEST.
ISENTROPIC PROGS OF 300-305K LAYER DO INDICATE A RAPID UPTICK IN
ISENTROPIC FORCING TOWARD LATE MORNING/MIDDAY. THIS EVOLUTION
WILL ALLOW THE HIGHER LEVEL THETA-E AIR TO RETURN NORTHWARD,
PARTICULARLY BY THURSDAY EVENING. SHOWERS WITH SOME EMBEDDED
STORMS ARE EXPECTED TO ACCOMPANY THIS STRONGER ADVECTIVE PUSH
THURSDAY AFTERNOON. DESPITE THE STRONG ADVECTION, A STRONG LOW
LEVEL INVERSION WILL DEVELOP IN RESPONSE AND THUS SENSIBLE
WARMING AT THE SURFACE LIKELY TO BE MORE LIMITED KEEPING HIGHS
IN THE 60S (POSSIBLY RETURN OF SOME LOW 70S LATE DAY/TOWARD
EVENING ACROSS THE SOUTH). SEVERE WEATHER IS NOT EXPECTED DURING
THE DAY THURSDAY GIVEN WEAK MID/UPPER LEVEL FORCING OUTSIDE OF
THE STRONG ADVECTIVE FORCING AND DUE TO THE ELEVATED NATURE OF
THE INSTABILITY.
FOR THURSDAY NIGHT, THE AFOREMENTIONED UPSTREAM FACING SHOULD BEGIN
TO INDUCE CYCLOGENESIS OF ASSOCIATED LOW PRESSURE, HOWEVER SOME
SUBTLE BUT IMPORTANT TRENDS IN GUIDANCE HAVE BEEN NOTED. A
SUBTLE TREND OF SLIGHTLY MORE POSITIVE TILT WITH THE UPPER
TROUGH APPEARS TO BE SUGGESTING SFC LOW DEEPENING RATES WILL BE
A LITTLE LESS IMPRESSIVE AND MORE DELAYED THAN EARLIER
INDICATIONS. ROBUST SHEAR PROFILES WILL DEVELOP AHEAD OF PRIMARY
LOW/SFC COLD FRONT BUT NORTHWARD EXTENT OF A QUALITY NARROW
WARM SECTOR REMAINS UNCERTAIN, ESPECIALLY CONSIDERING THE TREND
OF LESS RAPID SFC FEATURE DEEPENING. THERE DOES STILL APPEAR TO
BE A NARROW TEMPORAL WINDOW FOR WEAK NEAR SFC INSTABILITY ACROSS
THE SOUTH DEPENDING ON EXTENT OF WARM FRONTAL PROGRESSION, BUT
HI RES ENSEMBLE MEANS STILL SUPPORT BEST SURFACE-BASED AND
MIXED-LAYER CAPE REMAINING ACROSS CENTRAL/SOUTHERN IN. ONLY
MINOR CHANGES WERE MADE TO SWODY2 WITH A MARGINAL RISK OF SEVERE
STORMS PERSISTING SOUTH OF US 24, AND MAINLY FOR THE EVENING
HOURS THURSDAY. SOME ISOLATED WIND/TORNADO RISK IS POSSIBLE
WHERE SOME WEAK MLCAPE CAN OVERSPREAD GIVEN BACKGROUND LOW AND
DEEP LAYER SHEAR, BUT CURRENT PARAMETER SPACE WOULD TEND TO BE
MORE SUPPORTIVE OF ISOLATED SEVERE THREAT SOUTHWEST/SOUTH OF
LOCAL AREA FROM SOUTHERN IL INTO CENTRAL IN. ANOTHER LIMITING
FACTOR FOR SEVERE POTENTIAL COULD BE MORE DELAYED IMPRESSIVE
DYNAMICS DUE TO THE WEAK POSITIVE TILT OF THIS SYSTEM.
OTHERWISE, SOME BRIEF LOCALLY HEAVY RAIN IS POSSIBLE WITH HIGHLY
ANOMALOUS 1.75+ INCH PWATS WORKING INTO THE AREA AHEAD OF THE
OVERNIGHT COLD FRONTAL PASSAGE.
FRIDAY STILL APPEARS TO BE BLUSTERY/WINDY DAY WITH STRONG COLD
ADVECTION ON THE BACK SIDE OF THIS SYSTEM. THIS SHOULD LEAD TO
DEVELOPMENT OF LAKE EFFECT RAIN SHOWERS AND A POTENTIAL OF MIXING
DOWN SOME STRONGER WIND GUSTS. WITH DEEPENING RATES OF THIS
SYSTEM PERHAPS A BIT WEAKER THAN EARLIER INDICATIONS AND SOME
SUGGESTION OF A GREAT LAKES MODIFICATION OF SECONDARY LOW LEVEL
TROUGH LATE IN THE DAY, GUIDANCE HAS BACKED OFF A BIT ON GUST
MAGNITUDE DURING THE DAY, BUT WOULD SUSPECT SOME GUSTS TO 30 TO
35 MPH WOULD BE POSSIBLE. A FEW GUSTS APPROACHING 40 MPH APPEAR
MOST LIKELY NEAR IMMEDIATE LAKE MICHIGAN SHORELINE. GIVEN COLD
ADVECTION, TEMPERATURES ARE NOT LIKELY TO MOVE MUCH FROM MORNING
LEVELS WITH NEAR STEADY TEMPS IN THE 50S EXPECTED.
NO MAJOR CHANGES HAVE BEEN MADE TO THE LONG TERM FORECAST AS BELOW
NORMAL TEMPERATURES WILL CONTINUE THROUGH THE WEEKEND. LOW
TEMPERATURES IN THE 30S ARE STILL ON TRACK WITH A POTENTIAL OF
PATCHY FROST. THE FRIDAY NIGHT POTENTIAL REMAINS SOMEWHAT MORE
UNCERTAIN AS SOME LINGERING LAKE EFFECT CLOUDS COULD PERSIST
ACROSS THE WEST, WHILE WINDS MAY NOT FULL DECOUPLE ACROSS THE
EAST. SATURDAY NIGHT STILL APPEARS TO BE BEST CHANCE OF PATCHY
FROST DEPENDING ON EXTENT OF SOUTHWEST RETURN FLOW WITH
DEPARTING HIGH PRESSURE.
MID/UPPER LEVEL FLOW IS STILL PROGGED TO RAPIDLY DEAMPLIFY EARLY
NEXT WEEK WHICH WILL RESULT IN CONDITIONS WARMING TO ABOVE NORMAL
LEVELS INTO THE LOWER 70S TOWARD THE END OF THE PERIOD.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 753 PM EDT WED OCT 14 2026
BRIEF PERIOD OF VFR/MVFR ALTERNATING TONIGHT INTO EARLY TOMORROW,
EVENTUALLY DETERIORATING TO MVFR/IFR AS A LOW PRESSURE SYSTEM
MOVES INTO THE AREA DURING THE AFTERNOON. MORE PERSISTENT RAIN
SHOWERS BEGINNING IN THE 18-21Z TIME FRAME AND BEYOND THE TAF
PERIOD. THUNDERSTORMS ARE POSSIBLE, CLOSER TO 21-00Z. HANDLED
WITH PROB30 GROUPS FOR NOW GIVEN IT'S LATER IN THE PERIOD.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT FOR
LMZ043-046.
DISCUSSION...MARSILI
AVIATION...MCD
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