284  
FXUS63 KIND 180042  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
842 PM EDT FRI AUG 17 2018  
   
UPDATE
 
 
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.  
 

 
   
SYNOPSIS
 
 
ISSUED AT 225 PM EDT FRI AUG 17 2018  
 
RAIN CHANCES WILL CONTINUE TONIGHT AS LOW PRESSURE MOVES ACROSS  
AND EXITS THE AREA. A FEW LINGERING SHOWERS WILL BE POSSIBLE EARLY  
ON SATURDAY AS THE LOW DEPARTS. HIGH PRESSURE IS EXPECTED TO  
BUILD ACROSS CENTRAL INDIANA ON SATURDAY AFTERNOON AND SATURDAY  
NIGHT. THIS WILL BRING DRY WEATHER FOR THE LATTER PARTS OF THE  
WEEKEND.  
 
ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO ARRIVE IN THE AREA ON  
MONDAY AND TUESDAY. THIS WILL BRING MORE RAIN CHANCES TO CENTRAL  
INDIANA EARLY NEXT WEEK. THAT LOW WILL DEPART BY MID  
WEEK...BRINGING A RETURN TO DRY WEATHER FOR THE END OF THE NEXT  
WORK WEEK.  
 
LOOK FOR TEMPERATURES TO REMAIN AT OR BELOW SEASONAL NORMALS OVER  
THE NEXT WEEK.  
 

 
   
NEAR TERM /TONIGHT/
 
 
ISSUED AT 837 PM EDT FRI AUG 17 2018  
 
SCATTERED CONVECTION CONTINUES ACROSS THE AREA, AS A MID LEVEL  
VORTICITY LOBE AND DIFFUSE SURFACE COLD FRONT DRIFT SOUTH THROUGH  
THE AREA.  
 
EXPECTING A GRADUAL DECREASE IN COVERAGE OF SHOWER ACTIVITY FROM  
THIS POINT ON AS HEATING IS LOST. HOWEVER, THE PRESENCE OF THE MID  
AND LEVEL AND SURFACE FEATURES SUGGESTS THE POTENTIAL FOR SOME  
SHOWERS AND THUNDERSTORMS WILL LINGER INTO THE EARLY MORNING HOURS  
OF SATURDAY.  
 
PREVIOUS DISCUSSION FOLLOWS.  
 
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE OVER  
LOWER MICHIGAN AND NORTHERN INDIANA. BROAD CYCLONIC FLOW WAS IN  
PLACE ACROSS THE REGION GOES16 SHOWS A SWIRLING CLOUDS ACROSS THE  
REGION...DENOTING THE CIRCULATION. POP UP CUMULUS CLOUDS WERE  
FOUND FILLING IN ANY CLEAR GAPS AS CONVECTIVE TEMPERATURES WERE  
REACHED. SURFACE FLOW WAS GENERALLY SOUTHERLY OR SOUTHWESTERLY AND  
DEW POINTS REMAINED IN THE VERY MOIST UPPER 60S AND LOWER 70S.  
RADAR SHOWS SHOWER DEVELOPMENT OVER WESTERN CENTRAL INDIANA AS  
CONVECTIVE TEMPERATURES WERE BEING REACHED.  
 
MODELS THIS AFTERNOON SUGGEST A WEAK SHORT WAVE EMBEDDED WITHIN  
THE TROUGHY FLOW ALOFT PASSING ACROSS CENTRAL INDIANA. THIS  
COMBINED WITH SOME AFTERNOON HEATING SHOULD LEAD TO SOME SCATTERED  
SHOWERS LASTING INTO THE EVENING HOURS. TIME HEIGHT SECTIONS  
CONTINUE TO SHOWS GOOD LIFT THROUGH THE LATE AFTERNOON AND PAST  
00Z WITH GOOD LOWER LEVEL MOISTURE AVAILABLE. FORECAST SOUNDINGS  
AGAIN SHOW FAVORABLE LAPSE RATES FOR AFTERNOON CONVECTION. HRRR  
ALSO SUGGESTS SHOWER AND STORM DEVELOPMENT THIS  
AFTERNOON...CONTINUING INTO THE EVENING. THUS WILL TREND POPS AT  
OR ABOVE THE FORECAST BUILDER BLENDS WITH THIS FAVORABLE SET-UP  
FOR RAIN.  
 
TROUGH AXIS IS EXPECTED TO PIVOT SOUTHEAST ACROSS THE FORECAST  
AREA OVERNIGHT...AND RAIN CHANCES SHOULD DIMINISH AS THIS AXIS  
PASSES ALONG WITH THE LOSS IF DAYTIME HEATING. THUS FOR NOW...WILL  
FOCUS BEST POPS IN THE 20Z-04Z TIME FRAME...TRENDING DOWNWARD  
AFTER THAT. GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND LOWS  
AT OR ABOVE THE FORECAST BUILDER BLENDS.  
 

 
   
SHORT TERM /SATURDAY THROUGH MONDAY/
 
 
ISSUED AT 225 PM EDT FRI AUG 17 2018  
 
MODELS SHOW THE TROUGH AXIS SAGGING SOUTHEAST OF CENTRAL INDIANA  
ON SATURDAY MORNING AS NW FLOW DEVELOPS ALOFT. FORECAST SOUNDINGS  
RESPOND WITH A DRY COLUMN AS THE GFS SHOWS A GOOD MID LEVEL  
INVERSION ARRIVING BY 12Z. TIME HEIGHTS SHOW SUBSIDENCE ARRIVING  
BY 15Z. THUS FORECAST BUILDER WILLING...WILL TRY AND TREND TOWARD  
A DRY FORECAST FOR SATURDAY WITH DECREASING CLOUDS IN THE WAKE OF  
THE FRONT. WITH MINIMAL TEMPERATURE ADVECTION IN PLACE...WILL  
TREND HIGHS CLOSE TO THE FORECAST BUILDER BLENDS.  
 
ON SATURDAY NIGHT THROUGH SUNDAY NIGHT THE MODELS CLEARLY SHOW  
STRONG HIGH PRESSURE IN PLACE ACROSS THE REGION...STRETCHING FROM  
ONTARIO...ACROSS THE GREAT LAKES TO THE OHIO VALLEY. FORECAST  
SOUNDINGS AGAIN SHOW A DRY COLUMN AND SUBSIDENCE IS DEPICTED  
WITHIN THE MIDDLE LEVELS. THUS WILL TREND TOWARD A DRY FORECAST  
HERE AND STICK CLOSE TO THE FORECAST BUILDER TEMPERATURES FOR  
HIGHS AND LOWS.  
 
ON MONDAY THE GFS SUGGESTS LOW PRESSURE PUSHING TOWARD INDIANA  
FROM THE CENTRAL MISSISSIPPI RIVER VALLEY. MODELS SUGGEST BY MID  
TO LATE IN THE DAY ON MONDAY...A WARM FRONT WILL ARRIVE IN  
CENTRAL INDIANA AHEAD OF THE DEEPENING LOW OVER ILLINOIS.  
ALOFT...THE GFS SHOW A FAVORABLE UPPER LEVEL TROUGH WITH AMPLE  
FORCING. THUS WILL TREND TOWARD HIGH POPS LATE IN THE DAY AS THESE  
FEATURE ARRIVE.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
ISSUED AT 330 PM EDT FRI AUG 17 2018  
 
PRIMARY FOCUS OF THE LONG TERM WILL BE EARLY IN THE PERIOD AS A LOW  
PRESSURE SYSTEM MOVES THROUGH THE GREAT LAKES. THIS WILL NECESSITATE  
PRECIPITATION CHANCES IN THE FIRST 48 HOURS OR SO BEFORE A LARGE AND  
SOMEWHAT FALL-LIKE HIGH PRESSURE SYSTEM PUSHES INTO THE REGION,  
BRINGING DRY AND SOMEWHAT COOLER WEATHER RIGHT ON TIME MID TO LATE  
WEEK AS METEOROLOGICAL SUMMER NEARS ITS CLOSE.  
 
BLENDED INITIALIZATION WAS GENERALLY ACCEPTABLE MINUS REMOVING SOME  
SPOTTY SLIGHT CHANCES LATE IN THE WEEK.  
 

 
   
AVIATION /DISCUSSION FOR THE 180000Z TAFS/
 
 
ISSUED AT 632 PM EDT FRI AUG 17 2018  
 
SCATTERED CONVECTION IS EXPECTED TO LINGER IN THE VICINITY OF THE  
TERMINALS THROUGH ABOUT SUNSET, AS A MID LEVEL VORTICITY LOBE AND  
SURFACE COLD FRONT, MOVE THROUGH.  
 
OTHERWISE, LIGHT WINDS AND A HUMID AIR MASS MAY LEAD TO THE  
DEVELOPMENT OF IFR CEILINGS, ALONG WITH SOME FOG, AFTER 180600Z.  
NOT SURE HOW WIDESPREAD THESE CONDITIONS WILL GET AT THIS TIME, AS  
SOME LINGERING MID LEVEL CLOUD MAY WORK AGAINST THE LOW CEILINGS  
FORMING.  
 
SURFACE WINDS 240-290 DEGREES AT 5-8 KTS EARLY THIS EVENING WILL  
BECOME LIGHT AFTER SUNSET.  
 

 
   
IND WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SYNOPSIS...PUMA  
NEAR TERM...PUMA/JAS  
SHORT TERM...PUMA  
LONG TERM...NIELD  
AVIATION...JAS  
 
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