029  
FXUS63 KIWX 201835  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
235 PM EDT SAT OCT 20 2018  
   
SYNOPSIS
 
 
ISSUED AT 235 PM EDT SAT OCT 20 2018  
 
WINDY CONDITIONS WILL CONTINUE THROUGH THE EARLY EVENING WITH  
WIDESPREAD GUSTS TO 45 MPH AND ISOLATED HIGHER GUSTS POSSIBLE.  
SHOWERS WILL ALSO CONTINUE WITH ISOLATED STORMS THAT COULD PRODUCE  
SOME SMALL HAIL. A FEW LAKE EFFECT RAIN SHOWERS EXPECTED OVERNIGHT  
THAT COULD BRIEFLY MIX WITH SNOW AT TIMES BUT NO ACCUMULATION IS  
EXPECTED. A RETURN TO COOL AND QUIET WEATHER IS EXPECTED FOR MUCH OF  
NEXT WEEK.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TONIGHT)  
ISSUED AT 235 PM EDT SAT OCT 20 2018  
 
PREVIOUS UPDATE DISCUSSION REMAINS VALID CONCERNING WIND ADVISORY.  
ALREADY HAVE A FEW REPORTS OF 40+ KT GUSTS AND THIS SHOULD CONTINUE  
THROUGH THE EARLY EVENING BASED ON UPSTREAM OBS AND FORECAST  
SOUNDINGS/TIME-HEIGHT CROSS SECTIONS OF WIND AND STABILITY PROFILES.  
02Z END TIME MAY BE A TAD LATE BUT IT WILL STILL BE GUSTY THROUGH  
THAT TIME. A FEW STORMS HAVE DEVELOPED DOWNWIND OF LAKE MICHIGAN  
WITH 0.25-0.5 INCH HAIL AND ISOLATED STRONGER WINDS. THIS WILL ALSO  
REMAIN POSSIBLE THROUGH THE AFTERNOON THOUGH LOW LEVEL CAA AND LOSS  
OF DIABATIC HEATING WOULD SUGGEST A GENERAL DOWNWARD TREND IN  
STRENGTH OF CONVECTION.  
 
MAIN ISSUE FOR THE REST OF THE PERIOD WILL BE LAKE EFFECT POTENTIAL  
OVERNIGHT...TO WHICH NOT MUCH HAS CHANGED IN LATEST FORECAST  
THINKING. IMPRESSIVE SHORTWAVE EXITS QUICKLY THIS EVENING WITH  
QUICKLY RISING HEIGHTS/AVA YIELDING SHARP INCREASE IN SUBSIDENCE AND  
LOWERING INVERSION HEIGHTS. HOWEVER, LATEST FORECAST SOUNDINGS  
(INCLUDING HI-RES/RAPID UPDATE) STILL INDICATE CONVECTIVE DEPTHS  
DEEP ENOUGH TO SUPPORT SOME SCT SHOWERS GIVEN INCREDIBLE LAKE-  
INDUCED INSTABILITY AS CLEARLY EVIDENT FROM RECENT RADAR TRENDS.  
FETCH REMAINS NNW THROUGH ROUGHLY 06Z WITH SOME WEAK CONVERGENCE  
SIGNAL. THIS SHOULD BE ENOUGH TO MAINTAIN AT LEAST SCT/CELLULAR  
SHOWERS THROUGH MUCH OF THE OVERNIGHT. WINDS QUICKLY BACK SUNDAY  
MORNING AND DO NOT ANTICIPATE ANY PRECIP AFTER 12Z.  
 
PRECIP TYPES REMAIN PROBLEMATIC WITH THETA-E FLUX AND LAKE EFFECT  
CLOUDS LIKELY HOLDING SURFACE WET BULB TEMPS JUST ABOVE FREEZING.  
YET ANY HEAVIER SHOWERS WILL EASILY YIELD SNOW AS PREDOMINATE PRECIP  
TYPE AND SOME POTENTIAL FOR EVEN LIGHT SNOW TO MIX IN LATER TONIGHT.  
A BRIEF DUSTING ON GRASSY SURFACES NOT ENTIRELY IMPOSSIBLE IN ANY  
HEAVIER BURSTS BUT WILL CERTAINLY NOT LAST LONG.  
 

 
   
LONG TERM
 
(SUNDAY THROUGH SATURDAY)  
ISSUED AT 235 PM EDT SAT OCT 20 2018  
 
IN STARK CONTRAST TO THE ACTIVE SHORT TERM...LONG TERM PERIOD IS  
INCREDIBLY DULL. HIGH AMPLITUDE RIDGE SETS UP OVER THE WESTERN CONUS  
AND SLOWLY MIGRATES EAST WITH CONFLUENT FLOW DOWNSTREAM. A FEW  
SHORTWAVES ROTATE THROUGH THE EASTERN CANADA UPPER LOW. THE  
STRONGEST OF WHICH WILL CROSS THE GREAT LAKES MONDAY NIGHT BUT  
DRY/STABLE CONDITIONS AND LIMITED FORCING (ESPECIALLY IN OUR AREA)  
WILL KEEP TRAILING COLD FRONT DRY. AFTER A RELATIVELY WARM DAY  
MONDAY WITH HIGHS POSSIBLY NEAR 60F...SLIGHTLY COOLER AIR RETURNS  
FOR THE REST OF THE WEEK. NEXT CHANCE FOR PRECIP WILL NOT ARRIVE  
UNTIL FRIDAY INTO NEXT WEEKEND WHEN NEXT LONGWAVE TROUGH ARRIVES.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)  
ISSUED AT 149 PM EDT SAT OCT 20 2018  
 
VFR TO MVFR CONDITIONS ARE EXPECTED THIS AFTERNOON AND EVENING AS A  
COLD FRONT MOVES THROUGH THE AREA. RAIN SHOWERS WILL BE NUMEROUS,  
AND THERE IS EVEN POTENTIAL FOR AN ISOLATED THUNDERSTORM (THOUGH NOT  
ENOUGH CONFIDENCE FOR THE TAF). IN HEAVIER SHOWERS, WE COULD SEE A  
MIX OF GRAUPEL OR SMALL HAIL. VISIBILITIES WILL BE REDUCED TO MVFR  
WITHIN THESE SHOWERS. OTHERWISE, EXPECT WINDY CONDITIONS TO CONTINUE  
THROUGH LATE EVENING, SHIFTING TO THE NORTHWEST BEHIND THE FRONT  
THIS AFTERNOON. GUSTS WILL LARGELY RANGE FROM 35-45 MPH, WITH A FEW  
STRONGER ONES OF 45-50 MPH IN ANY HEAVIER SHOWERS OR STORMS.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...WIND ADVISORY UNTIL 10 PM EDT /9 PM CDT/ THIS EVENING FOR  
INZ003>009-012>018-020-022>027-032>034.  
 
MI...WIND ADVISORY UNTIL 10 PM EDT THIS EVENING FOR MIZ077>081.  
 
OH...WIND ADVISORY UNTIL 10 PM EDT THIS EVENING FOR OHZ001-002-004-  
005-015-016-024-025.  
 
LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ043-046.  
 

 
 

 
 
SYNOPSIS...AGD  
SHORT TERM...AGD  
LONG TERM...AGD  
AVIATION...MCD  
 
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