466
FXUS63 KIWX 131820
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
220 PM EDT TUE MAY 13 2025
KEY MESSAGES
- SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON, AND
AGAIN WEDNESDAY AFTERNOON.
- VERY WARM ON THURSDAY WITH HIGHS WELL INTO THE 80S.
- WHILE THE DAYTIME WILL BE PRIMARILY DRY THURSDAY, THERE IS A
CHANCE FOR THUNDERSTORMS THURSDAY EVENING AND OVERNIGHT, SOME
OF WHICH MAY BE SEVERE.
DISCUSSION
ISSUED AT 220 PM EDT TUE MAY 13 2025
UPPER LOW CENTER OVER THE WESTERN TN VALLEY WILL FINALLY GET A PUSH
NORTH INTO THE OH VALLEY AND SOUTHERN GREAT LAKES TONIGHT INTO
WEDNESDAY IN RESPONSE TO A DEEP UPPER TROUGH EDGING EAST TOWARD THE
ROCKIES. THIS SYSTEM WILL CONTINUE TO GENERATE ISOLATED TO SCATTERED
SHOWERS AND STORMS (MAINLY DIURNAL) THANKS TO A MOIST COLUMN THROUGH
MUCH OF THE TROPOSPHERE AND JUST ENOUGH DIURNAL HEATING, WITH THE
GREATEST COVERAGE LIKELY FOCUSED NEAR SMALL SCALE VORT LOBES
ROTATING AROUND THE UPPER LOW. OVERALL WEAK DYNAMICS, FLOW AND
INSTABILITY PRECLUDES A SEVERE WX RISK WITH LIGHTNING, BRIEF
DOWNPOURS AND COLD AIR FUNNELS POSSIBLE WITH HEAVIER SHOWERS EACH
AFTERNOON.
THE ROCKIES UPPER LOW WILL EJECT INTO THE NORTHERN PLAINS AND UPPER
MIDWEST THURSDAY INTO THURSDAY NIGHT WITH AN ASSOCIATED STRONG SFC
LOW EMERGING OVER MN BY FRIDAY MORNING PER LATEST GUIDANCE. A
LEADING WARM FRONT AND LOW LEVEL THETA-E RIDGE ADVECT INTO THE LOCAL
AREA ON THURSDAY WITH WARM TEMPS (NEAR RECORDS) AND A CONDITIONAL
SEVERE RISK THURSDAY NIGHT. PROGGED SHEAR/INSTABILITY PROFILES CHECK
THE BOX FOR POTENTIAL DEEP/SEVERE CONVECTION, HOWEVER, DELAYED
FORCING AND WHAT LOOKS TO BE A VERY WARM EML BASE MAY KEEP A LID ON
ORGANIZED CONVECTION ALONG AN INCOMING PRE-FRONTAL TROUGH OR
CONVECTIVE OUTFLOW.
HEIGHT FALLS EVENTUALLY SLIDE EAST THROUGH THE GREAT LAKES FRIDAY
INTO SATURDAY WITH THE UPCOMING WEEKEND TRENDING COOLER, DRY AND
BREEZY IN RESPONSE TO THE SUPPRESSION. COULD SEE ANOTHER FRONTAL
WAVE DRIVE A CONVECTIVE COMPLEX THROUGH THE REGION FRIDAY PM IN THIS
TRANSITION, THOUGH THE BULK OF GUIDANCE CONTINUES TO FAVOR AREAS OFF
THE SOUTH FOR MORE ORGANIZED CONVECTION CHANCES. THURSDAY NIGHT'S
ACTIVITY, OR LACK THEREOF, WILL DICTATE THE TIMING/TRACK OF FRIDAY'S
POTENTIAL CONVECTIVE SYSTEM.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 138 PM EDT TUE MAY 13 2025
MODEST HEATING AND AT LEAST SOME INSTABILITY IS ALLOWING FOR A
SLOW INCREASE IN COVERAGE OF SHOWERS WHICH HAVE ALREADY
IMPACTED KFWA. CIGS/VSBYS WILL BE RATHER VARIABLE THROUGH 00Z,
BUT SHOULD RESIDE MAINLY IN THE MVFR RANGE OUTSIDE OF ANY
CONVECTION. FOR THE TIME BEING HAVE REMOVED THE TEMPO GROUP FOR
THUNDER AS CONFIDENCE IN DURATION AND COVERAGE ISN'T QUITE HIGH
ENOUGH TO WARRANT A 4 HOUR PERIOD. SOME LIGHTNING IS NOTED
UPSTREAM (SE OF THE SITE) THAT COULD MAYBE SIGNAL A SMALL PERIOD
OF THUNDER LATER. WILL AMEND IF NEEDED. AT KSBN, SOME SHOWERS
WILL BE NEARBY, BUT CONFIDENCE ON COVERAGE AND IMPACTS THERE IS
EVEN LOWER. HAVE KEPT WITH A POP30 THIS AFTERNOON AND WILL SEE
HOW THE COVERAGE EVOLVES. HIGHER END MVFR CIGS ARE LIKELY TO
STICK AROUND WITH ANY SHOWERS BRINGING A SHOT FOR BRIEF IFR
CIGS.
ANY CONVECTION SHOULD QUICKLY WIND DOWN AFTER 00Z. GIVEN THE
MOIST ATMOSPHERE, WILL NEED TO WATCH FOR STRATUS DECK TO LOWER
OVERNIGHT WITH IFR CIGS AT 1 OR BOTH SITES. WILL FINE TUNE IN
LATER FORECASTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...STEINWEDEL
AVIATION...FRAZIER
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