185  
FXUS63 KIWX 190942  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
542 AM EDT TUE MAR 19 2024  
   
KEY MESSAGES
 
 
- GUSTY WINDS BETWEEN 30 AND 40 MPH ARE EXPECTED TODAY WITH A  
FEW SPORADIC 45 MPH GUSTS POSSIBLE.  
 
- COLD, BELOW FREEZING OVERNIGHT LOW TEMPERATURES ARE EXPECTED  
TONIGHT THROUGH THE WEEKEND WITH THE COLDEST LOWS OCCURRING  
WEDNESDAY AND SATURDAY NIGHTS, WHEN LOWS IN THE 20S ARE  
LIKELY.  
 
- THE NEXT CHANCE FOR PRECIPITATION IS LATER THURSDAY NIGHT  
THROUGH FRIDAY WITH SOME COMBINATION OF SNOW AND RAIN  
POSSIBLE.  
 
 

 
   
DISCUSSION
 
 
ISSUED AT 316 AM EDT TUE MAR 19 2024  
 
THE TROUGH AND ITS ATTENDANT VORTICITY THAT BROUGHT THE COLDER  
TEMPERATURES MONDAY SHIFTS EAST AS SURFACE HIGH PRESSURE NOSES INTO  
THE AREA FROM THE SOUTH. MEANWHILE, A SECOND VORT MAX PASSES THROUGH  
THE NORTHERN GREAT LAKES TODAY FORCING A CLIPPER SYSTEM ON A TRACK  
EASTWARD TO NORTH. PLENTY OF LOW LEVEL DRY AIR WILL KEEP ANY  
PRECIPITATION AT BAY DESPITE THE PASSAGE OF A COLD FRONT THIS  
AFTERNOON AND EVENING. WARM AIR ADVECTION OUT IN FRONT OF THE COLD  
FRONT WILL HELP WARM TEMPERATURES BACK INTO THE MID 40S TO MID 50S  
TODAY AND WILL ALSO PROVIDE A LOW LEVEL INVERSION RESTRICTING  
MIXING. A 45 KT LOW LEVEL JET WILL SLIDE THROUGH THE AREA TODAY  
INCREASING WIND GUSTS ACROSS THE AREA. NAM BUFKIT SOUNDINGS INDICATE  
30-39 KT (35 TO 44 MPH) GUSTS COULD EASILY BE BROUGHT DOWN TO THE  
SURFACE WITH THE OCCASIONAL 40 KT (AROUND 45 MPH) GUST POSSIBLE. THE  
UPPER MIXING THRESHOLD SEEMS TO REACH 45 TO 50 KTS, WHICH MAY ALLOW  
THE COLD FRONT TO BRING DOWN SUCH WINDS. AM A LITTLE SKEPTICAL OF  
SUCH AN OCCURRENCE GIVEN THE WARM ADVECTION PATTERN WE'RE IN. WITH  
THE DRY AIR (30-40 PERCENT MINRH VALUES), WARM TEMPERATURES,  
AND GUSTY WINDS, THIS IS GENERALLY THE FIRST CLUE FOR FIRE  
WEATHER, HOWEVER, THE 10 HR FUELS ARE STILL A LITTLE MOIST IN  
THE 10-15 PERCENT RANGE AS OPPOSED TO THE SINGLE DIGITS, WHICH  
WOULD POINT TO MORE SPORADIC GRASS FIRES IF ANYTHING DOES GET  
GOING. WITH THE AFOREMENTIONED TROUGH AXIS SHIFTING EASTWARD  
TODAY, 850 MB TEMPERATURES WILL BE INCREASING OVERNIGHT AND THE  
BOUNDARY LAYER REMAINS COUPLED ENOUGH TO RESTRICT RADIATIONAL  
COOLING SUCH THAT WE BOTTOM OUT IN THE LOW 30S TO UPPER 20S AS  
OPPOSED TO THE MID TO UPPER 20S LAST NIGHT.  
 
AS IS TYPICAL BEHIND CLIPPER SYSTEMS, THE SURFACE HIGH PRESSURE  
SYSTEM FOLLOWING BEHIND IT NOSES IN KEEPING THE AREA DRY WEDNESDAY  
AND THURSDAY. THE COLD ADVECTION BEHIND THE CLIPPER SYSTEM HELPS  
HIGH TEMPERATURES FALL BACK BELOW SEASONAL NORMS TO BETWEEN THE MID  
30S AND THE MID 40S. ADDITIONALLY, IT WILL ALSO HELP LOWS TO FALL TO  
THE LOW 20S AND UPPER TEENS WEDNESDAY NIGHT IT'LL TAKE UNTIL  
THURSDAY TO RELAX THE PRESSURE GRADIENT OVERHEAD AS THE HIGH  
PRESSURE CENTER APPROACHES ALLOWING 25 TO 30 MPH GUSTS WEDNESDAY,  
BUT SUSTAINED WINDS FAILING TO EXCEED 10 KTS ON THURSDAY. WEDNESDAY  
MAY MAKE ANOTHER RUN AT FIRE WEATHER POTENTIAL WITH THE GUSTY WINDS  
AND DRY WEATHER (25 TO 40 PERCENT MINRH) ALONG WITH DRIER 10 HR  
FUELS.  
 
CHANCES FOR PRECIPITATION INCREASE THURSDAY INTO FRIDAY AS A LOW  
PRESSURE SYSTEM EJECTS OFF THE ROCKIES. A SETUP WHERE THE ENERGY FOR  
THIS SYSTEM ACTUALLY GOES TO THE NORTH AND THE MOISTURE PLUME STAYS  
TO THE SOUTH IS A POSSIBILITY WITH THIS SYSTEM, WHICH MAY MAKE FOR A  
LATER START TIME AND COULD CUT OUT ANY SNOW MENTION AT ALL. THE GFS  
SEEMS TO ADVERTISE SUCH A SOLUTION, BUT IT'S AN OUTLIER FROM THE EC  
AND GEM SOLUTIONS. IT DOES LOOK LIKE WARMING TAKES PLACE EVEN ON THE  
ECMWF DESPITE PRECIPITATION OCCURING IN ITS SOLUTION SO RAIN MAY BE  
ABLE TO MIX IN DURING THE DAY TIMES. THIS LOOKS TO VACATE THE AREA  
FRIDAY NIGHT. WE ARE CURRENTLY ADVERTISING UPPER 30S TO UPPER 40S  
FOR HIGHS FRIDAY, BUT, AGAIN, DEPENDING ON IF IT PRECIPITATES, COULD  
SEE THESE DROPPING IN FUTURE RUNS.  
 
THE WEEKEND HAS BEGUN TO LOOK DRIER AS AN UPPER LOW OVER EASTERN  
CANADA HAS TRENDED SOUTHWARD SLOWING THE ADVANCE OF MOISTURE OUT OF  
THE PLAINS TOWARDS THE REGION. TEMPERATURES TREND WARMER THROUGH THE  
40S ON SATURDAY TO REACHING 50 IN OUR SOUTH SUNDAY. MODELS DIVERGE,  
NEXT WEEK, AS IT PERTAINS TO THE SHARPNESS OF THE TROUGH EJECTING  
FROM THE SOUTHWEST. IT COULD CAUSE A LOW PRESSURE SYSTEM TO RIDE  
NORTHWARD TO THE WEST OF OUR REGION OR IT MAY GRAZE OUR WEST.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
 
 
ISSUED AT 542 AM EDT TUE MAR 19 2024  
 
VFR THIS PERIOD. FAST MOVING CLIPPER SKIRTING THE NRN LAKES WILL  
YIELD A PERIOD OF INTENSE WARM ADVECTION TODAY WITH DEEP MIXING  
DEVELOPING RAMPING THROUGH THIS MORNING. SWRLY WINDS WILL ESCALATE  
QUICKLY AFTER SUNRISE WITH PEAK GUSTS TO 40KTS OR BETTER THIS AFTN.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ043-  
046.  
 

 
 

 
 
DISCUSSION...ROLLER  
AVIATION...T  
 
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