584
FXUS63 KIWX 140714
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
314 AM EDT WED MAY 14 2025
KEY MESSAGES
- PATCHY DENSE FOG THIS MORNING MIXES OUT SOON AFTER SUNRISE.
- SCATTERED SHOWERS AND THUNDERSTORMS TODAY, PRIMARILY IN THE
AFTERNOON.
- VERY WARM ON THURSDAY WITH A CHANCE FOR SEVERE THUNDERSTORMS
IN THE EVENING AND OVERNIGHT. CONFIDENCE IS LOW IN SEVERE
WEATHER OCCURRING.
DISCUSSION
ISSUED AT 312 AM EDT WED MAY 14 2025
FOG, SOME DENSE AS OF ABOUT 1AM EDT, HAS DEVELOPED AMID A VERY
SOUPY ENVIRONMENT PAIRED WITH RECENT RAINFALL. WILL CONTINUE TO
MONITOR THE TRENDS IN OBSERVATIONS BUT RIGHT NOW, AREAS OF EAST OF
IN-15 HAVE THE GREATEST NUMBER OF 1/4 MILE OBSERVATIONS, BUT EVEN SO
THERE ARE SOME 5-MILE VISIBILITIES MIXED IN.
CUT OFF UPPER-LEVEL LOW CONTINUES TO SWIRL OVER THE OHIO VALLEY. A
REPEAT PERFORMANCE OF YESTERDAY IS ANTICIPATED WITH RESPECT TO
SHOWER AND THUNDERSTORM COVERAGE. THIS ACTIVITY IS POISED ONCE AGAIN
TO FAVOR THE GREATER I-69 CORRIDOR WHERE MOISTURE CONVERGENCE AND
SPOKES OF VORTICITY ARE COLOCATED. THIS ACTIVITY WILL BE DIURNALLY
DRIVEN, SO, LOOK FOR INCREASING CHANCES FOR RAINFALL AS THE DAY
PROGRESSES.
THE PRIMARY ITEM OF CONCERN IN THIS FORECAST PERIOD REMAINS VERY HOT
CONDITIONS THURSDAY FOLLOWED BY A SLIGHT RISK (AND ENHANCED RISK PER
SPC) OF SEVERE THUNDERSTORMS. A PRIMARILY DRY DAY, PARTLY CLOUDY
SKIES, AND A 576DM RIDGE NOSING IN ARE ALL SETTING THE STAGE FOR
HIGHS THURSDAY TO BE WELL INTO THE 80S. COMPARED TO A FEW DAYS AGO,
THE GUIDANCE HAS FORMED A CONCENSUS OF HIGHS IN THE MID-TO-UPPER
80S; GOOD FOR 75TH PERCENTILE OF MODEL GUIDANCE (IT WAS PREVIOUSLY A
99TH PERCENTILE FORECAST CLOSER TO 90 DEGREES). CANNOT COMPLETELY
RULE OUR FAR SOUTHWESTERN AREAS (MONTICELLO, LOGANSPORT) CRACKING 90
DEGREES, WHICH WOULD APPEAR TO BE AMONG THE TOP 10 EARLIEST 90-
DEGREE DAYS ON RECORD.
THURSDAY'S SEVERE THUNDERSTORM FORECAST REMAINS MURKY. WE FACE A
CONUNDRUM OF A POWDER-KEG ENVIRONMENT CAPPED BY AN ELEVATED MIXED
LAYER WITH MISMATCHED FORCING MECHANISMS. THE DAYTIME HOURS THURSDAY
APPEAR PRIMARILY DRY AND WE'RE NOT COMPLETELY OUT OF THE WOODS YET
FOR AN EVENING/OVERNIGHT SEVERE RISK, BUT THE FORECAST REMAINS
UNCERTAIN.
THERE ARE TWO FORCING MECHANISMS AT PLAY FOR STORMS THURSDAY. THE
FIRST IS A WARM FRONT ARRIVING FROM SOUTHWEST TO NORTHEAST DURING
THE MIDDAY HOURS. FORECAST SOUNDINGS AHEAD OF THE FRONT DEPICT A
CAPPED LOW-LEVEL ENVIRONMENT. IN THE WAKE OF THIS FRONT, THE LOW-
LEVEL PROFILE WARMS BY ABOUT 5C WHICH FURTHER STRENGTHENS THE
CAPPING INVERSION. CAMS GENERALLY HAVE AN UNASSUMING QPF FOOTPRINT
ASSOCIATED WITH THIS FRONT. THE ENVIRONMENT OTHERWISE HAS COPIOUS
CAPE VALUES AND 40 KNOTS OF SHEAR. BY LATE-AFTERNOON, FORECAST
SOUNDINGS DEPICT AN ELEVATED MIXED LAYER, FURTHER COMPLICATING THE
CHANCE OF STORMS.
THE SECOND FORCING MECHANISM, A COLD FRONT, ARRIVES TO NORTHWEST
INDIANA NEAR 00Z FRIDAY (7CT THURSDAY). EVEN SO, SOUNDINGS STILL
DEPICT A SUBTLE CAP IN PLACE LOCALLY. THE PARENT LOW OF THIS COLD
FRONT IS INCREDIBLY WRAPPED UP OVER MINNESOTA, FOCUSING THE BEST JET
DYNAMICS ACROSS SOUTHERN WI AND NORTHERN IL. INSTEAD, A SECONDARY
500-MB JET IS FOCUSED ACROSS CENTRAL IL AND IN, BUT THIS JET WOULD
ENHANCE CONVECTION SOUTH OF US 24. OVERALL, HAVE STAYED CLOSE TO THE
EXISTING POP FORECAST AND WILL FOCUS THIS MORNING'S MESSAGING ON
CONTINUED UNCERTAINTY FOR HOW THIS EVOLVES. THE ADVERTISED ENHANCED
WILL BE INCREDIBLY DEPENDENT ON IF WE CAN BREAK THE CAP.
LATER FRIDAY IS PERHAPS INCREASINGLY STORMY AS THE PRECEDING COLD
FRONT LAYS OUT ALONG AND SOUTH OF THE US 24 CORRIDOR AS THE UPPER-
MIDWEST LOW REDEVELOPS. ALONG AND SOUTH OF THIS FRONT IS
CHARACTERIZED BY HIGH CAPE AND AMPLE SHEAR (SLIGHTLY LESS THEN
THURSDAY). GUIDANCE CONTINUES TO ADVERTISE A THUNDERSTORM COMPLEX
OVER CENTRAL INDIANA, PERHAPS SNEAKING INTO COUNTIES SOUTH OF US 24.
COOLER AND DRY FOR THE WEEKEND BEFORE A WARMING TREND NEXT WEEK
ALONG WITH MORE WET WEATHER.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1210 AM EDT WED MAY 14 2025
EAST FLOW CONTINUES FOR ANOTHER NIGHT AT THE ONSET OF THE TAF
PERIOD. HOWEVER, UNLIKE LAST NIGHT, CEILINGS WERE LOWER AND
VISIBILITIES WERE FALLING BELOW A 1/2SM IN SOME PLACES. FWA HAD
A CEILING OF 004; SMD (SMITH FIELD) AT 003 AND GWB AT 005.
SOMEWHAT LIGHTER WINDS TONIGHT SHOULD ALLOW VISIBILITIES TO DROP
QUITE LOW AT FWA (HAVE 2SM WITH A TEMPO GROUP FROM 09Z-13Z DOWN
TO 1/2SM. VISIBILITIES WERE QUITE VARIABLE WITH PATCHY DENSE
FOG REPORTED IN MAINLY RURAL AND OPEN AREAS. CONDITIONS SHOULD
IMPROVE QUICKLY AFTER SUNRISE. ISOLATED TO SCATTERED
THUNDERSTORMS SHOULD DEVELOP AFTER 18Z WITH DAYTIME HEATING AS
A WEAK DISTURBANCES MOVES INTO THE AREA.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...BROWN
AVIATION...SKIPPER
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