564  
FXUS63 KIWX 191841  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
241 PM EDT SUN MAY 19 2024  
   
KEY MESSAGES
 
 
- STRONG TO POSSIBLY SEVERE THUNDERSTORMS STILL APPEAR POSSIBLE  
LATE TUESDAY NIGHT AND POSSIBLY AGAIN WEDNESDAY AFTERNOON.  
BOTH OF THESE PERIODS ARE MARKED BY LOW CONFIDENCE IN SEVERE  
WEATHER.  
 
- CHANCE OF STORMS FOR MONDAY AND MONDAY NIGHT. WIDESPREAD  
SEVERE WEATHER IS NOT EXPECTED, BUT AN ISOLATED STORM MAY HAVE  
A HAIL OR WIND THREAT.  
 
- WARM TEMPERATURES IN THE 80S THROUGH TUESDAY. 70 DEGREE  
TEMPERATURES TAKE OVER FOR THE LATE WEEK.  
 
- LULL IN PRECIP CHANCES FOR THURSDAY, BUT ADDITIONAL CHANCES OF  
SHOWERS AND THUNDERSTORMS NEXT WEEKEND.  
 

 
   
DISCUSSION
 
 
ISSUED AT 239 PM EDT SUN MAY 19 2024  
 
A COLD FRONT, DIVORCED FROM ANY MID LEVEL VORTICITY, STALLS JUST TO  
OUR NORTHWEST TODAY. A MOISTURE AXIS GLIDES INTO THE FORECAST AREA  
AND SHORT TERM GUIDANCE INDICATES LOW LEVEL CONVERGENCE WILL BE  
PRESENT IN AN ENVIRONMENT WITH STRONG LOW LEVEL LAPSE RATES AND CAPE  
VALUES EXCEEDING 2500 J/KG. FORECAST SOUNDINGS INDICATE THERE'S  
QUITE A BIT OF DRY AIR BELOW 850 AND ABOVE 700 MB THAT MIGHT MAKE IT  
A LITTLE BIT MORE DIFFICULT TO FORM STORMS, BUT SHOULD THEY OVERCOME  
IT SAY WITH A FEW OUTFLOW BOUNDARIES, DCAPE VALUES EXCEED 900 TO  
1000 J/KG MAKING DOWNBURSTS POSSIBLE. ADDITIONALLY, THE LOW LEVEL  
DRYNESS AND MID LEVEL LAPSE RATES BETWEEN 6.5 AND 7 C/KM COULD MAKE  
HAIL A POSSIBILITY WITH LIMITED MELTING IN THE DRY LOW LEVEL LAYER.  
PWATS DO ACTUALLY EXCEED CLIMATOLOGY BY 1 SD MAKING LOCALLY  
HEAVY RAIN POSSIBLE WITH THE 60F DEGREE DEW POINTS AND 10C 850  
MB DEW POINTS. SLOW STORM MOTIONS ALSO CONTRIBUTE TO THE HEAVY  
RAIN POSSIBILITY, WHICH COULD BE EXACERBATED OVER A MORE URBAN  
AREA. THERE IS ALSO SOME INDICATION THAT THESE STORMS CONTINUE  
BEYOND SUNSET WITH THE 500 TO 1000 J/KG OF MUCAPE REMAINING  
ALONG WITH 6.5 C/KM MID LEVEL LAPSE RATES AND AS A FRONT LIFTS  
NORTHWARD INTO MI MONDAY MORNING.  
 
MONDAY MORNING, THE AREA IS ONCE AGAIN DEVOID OF FORCING, BUT WE'LL  
BE WATCHING FOR THE ARRIVAL OF A LIKELY CONVECTIVELY ENHANCED  
SHORTWAVE FROM THE CENTRAL PLAINS TO ARRIVE IN THE EVENING. SHORT  
RANGE GUIDANCE INDICATES THIS COULD DIE ON OUR DOORSTEP, WHICH COULD  
HAPPEN AS THE SHORTWAVE APPEARS TO MOVE TOWARDS LOWER MICHIGAN, BUT  
LINGERING DIURNALLY ENHANCED INSTABILITY MAY BE ABLE TO HELP BEFORE  
SUNSET. FORECAST SOUNDINGS LOOK A LITTLE BIT SIMILAR TO TODAY'S  
SOUNDINGS, BUT CAPE APPEARS WEAKER. SIMILAR DCAPE AND MID LEVEL  
LAPSE RATE MAGNITUDES CONTRIBUTE TO WIND AND HAIL POTENTIAL, BUT  
SHEAR APPEARS MORE LIMITED PROVIDING SOME CEILING FOR STRONG TO  
SEVERE POTENTIAL. SPC'S MARGINAL RISK OF SEVERE WEATHER APPEARS  
WARRANTED FOR MONDAY, BUT WOULD WANT A LITTLE BIT MORE SHEAR AND  
TURNING IN THE LOW LEVELS TO MAKE A TORNADO THREAT A LITTLE BIT MORE  
BELIEVABLE.  
 
WITH SOME REMNANT SHORTWAVES NEARBY TUESDAY, WE MAY START WITH SOME  
CLOUDS AROUND, BUT MODELS INDICATE SOME CLEARING MAY BE POSSIBLE  
DURING THE AFTERNOON ALLOWING MODELS TO GENERATE 1500 J/KG OF CAPE.  
THE LOW LEVEL JET IS AROUND TUESDAY, WHICH MAY HELP TO REMOVE  
CLOUDINESS, BUT IT WON'T BE STRONG ENOUGH FOR SEVERE STORMS UNTIL  
LATER TUESDAY NIGHT. BY THAT POINT, 500 J/KG OF MUCAPE AND 6 TO 6.5  
C/KM MID LEVEL LAPSE RATES WILL BE AVAILABLE, WITH SHEAR FINALLY  
AROUND AFTER MIDNIGHT. EFFECTIVE HELICITY VALUES DO SURPASS 200  
M2/S2 DURING THIS TIME AS WELL, BUT MODELED SURFACE LCLS APPEAR TOO  
HIGH FOR A TORNADO UNLESS THOSE ARE INCORRECT. DCAPE DOESN'T APPEAR  
TO STAY AS HIGH OVERNIGHT, BUT GUSTY TO DAMAGING WINDS AND SOME HAIL  
STILL APPEAR POSSIBLE. SPC'S SLIGHT RISK APPEARS WARRANTED FOR  
TUESDAY INTO 12Z WEDNESDAY. THEN, WITH THE COLD FRONT BISECTING THE  
AREA INTO EAST AND WEST HALVES, THE EASTERN AREA HAS THE GREATEST  
CHANCE TO SEE AFTERNOON THUNDERSTORMS REFIRE, WEDNESDAY AFTERNOON,  
BUT THIS WILL DEPEND ON THE EVENTUAL PLACEMENT OF THE FRONT. TOO FAR  
EAST AND STORMS DEVELOP EAST OF OUR AREA. STORMS ARE MODELED TO HAVE  
1500 J/KG OF CAPE TO TAP INTO ALONG WITH SOME SHEAR AND 6 TO 6.5  
C/KM MID LEVEL LAPSE RATES. HELICITY APPEARS TO BE WEAKER FOR THIS  
SETUP, THOUGH. SPC'S SLIGHT RISK ALSO APPEARS WARRANTED FOR  
WEDNESDAY AFTERNOON.  
 
A BREAK IN THE ACTION IS INDICATED FOR THURSDAY AS SURFACE HIGH  
PRESSURE MOVES IN BEHIND THE FRONT. THERE IS A CHANCE THE DRY  
WEATHER CONTINUES FOR FRIDAY AS WELL WITH AN UPPER LOW IN SOUTHEAST  
CANADA AND THE STRENGTH OF A SHORTWAVE THROUGH THE TENNESSEE VALLEY  
LIKELY DETERMINING HOW FAR NORTH THE PRECIP SHIELD GETS. THERE IS A  
CHANCE OUR AREA COULD GET CLIPPED FRIDAY FROM THAT LOW TO OUR SOUTH.  
 
OUR NEXT CHANCE FOR SHOWERS AND PERHAPS THUNDERSTORMS APPEARS TO BE  
SATURDAY NIGHT/SUNDAY AS AN UPPER LOW IN SOUTH-CENTRAL CANADA DRAGS  
A COLD FRONT THROUGH THE AREA.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
 
 
ISSUED AT 1242 PM EDT SUN MAY 19 2024  
 
A STALLED/WEAK FRONT, LOCATED BETWEEN THE TERMINALS, SHOULD  
BECOME THE FOCUS FOR WIDELY SCATTERED CONVECTION LATER THIS  
AFTERNOON INTO THIS EVENING. THIS ACTIVITY SHOULD MAINLY REMAIN  
SOUTH OF KSBN WHILE BEING IN THE VICINITY OF KFWA DURING THIS  
TIME. A BRIEF VIS RESTRICTION AND WIND GUST UP TO 30 MPH  
POSSIBLE WITH ANY STORMS. VFR OTHERWISE THROUGH THE PERIOD.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...NONE.  
 

 
 

 
 
DISCUSSION...ROLLER  
AVIATION...STEINWEDEL  
 
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