359  
FXUS63 KIND 232021  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
321 PM EST SUN FEB 23 2020  
   
UPDATE
 
 
THE AVIATION SECTION HAS BEEN UPDATED BELOW.  
 

 
   
SYNOPSIS
 
 
ISSUED AT 245 PM EST SUN FEB 23 2020  
 
A LOW PRESSURE SYSTEM IS EXPECTED TO AFFECT THE AREA STARTING  
TONIGHT, AND LINGERING INTO THE MIDWEEK PERIOD. IN THE WAKE OF THIS  
SYSTEM, HIGH PRESSURE IS EXPECTED TO MOVE INTO THE AREA FOR THE  
LATER PARTS OF THE WEEK.  
 

 
   
NEAR TERM /TONIGHT/
 
 
ISSUED AT 245 PM EST SUN FEB 23 2020  
 
MODELS SUGGEST AN UPPER LOW, CURRENTLY OVER THE SOUTHERN ROCKIES,  
WILL MOVE INTO THE SOUTHERN PLAINS BY SUNRISE MONDAY. APPEARS MOST  
OF TONIGHT MAY END UP BEING DRY, WITH SOME LIFT AND DEEPER MOISTURE  
NOT EXPECTED TO MOVE INTO THE AREA UNTIL THE PRE DAWN HOURS OF  
MONDAY. LIFT DOESN'T LOOK PARTICULARLY STRONG LATE TONIGHT, WITH  
THE MAIN 850MB JET LOCATED WELL OFF TO THE SOUTHWEST, OVER THE  
SOUTHERN PLAINS. WILL START TO BRING IN CHANCE POPS FOR RAIN FROM  
THE SOUTHWEST AFTER 240600Z.  
 
LOW LEVEL THICKNESSES SUGGEST THE GFS MOS LOWS TONIGHT LOOK  
REASONABLE FOR THE MOST PART, SO LITTLE IF ANY ADJUSTMENTS  
PLANNED.  
 

 
   
SHORT TERM /MONDAY THROUGH WEDNESDAY/
 
 
ISSUED AT 245 PM EST SUN FEB 23 2020  
 
UNSETTLED WEATHER IS EXPECTED DURING MOST OF THE SHORT TERM. INITIAL  
UPPER LOW WILL EJECT ACROSS THE LOCAL AREA MONDAY NIGHT, BEFORE  
BEING ABSORBED BY A LARGER TROUGH THAT WILL REACH THE MIDWEST BY  
WEDNESDAY.  
 
WILL GRADUALLY INCREASE THE POPS DURING THE DAY MONDAY, AS MODELS  
SUGGEST THE BEST AREA OF LIFT MAY NOT PASS THROUGH THE LOCAL AREA  
UNTIL MONDAY AFTERNOON AND EVENING. AS A RESULT, THE HIGHEST POPS  
MAY BE AT THAT TIME.  
 
POPS WILL CONTINUE THROUGH WEDNESDAY, GIVEN THE SHARPENING UPPER  
TROUGH MOVING INTO THE AREA. THE MORE WIDESPREAD PRECIPITATION MAY  
BECOME MORE INTERMITTENT IN NATURE BY TUESDAY NIGHT AND WEDNESDAY,  
AS THE INTENSIFYING SURFACE LOW WILL LIFT OFF TO THE NORTHEAST BY  
THAT TIME.  
 
THICKNESSES LOOK HIGH ENOUGH FOR MOSTLY RAIN THROUGH TUESDAY. BY  
TUESDAY NIGHT INTO WEDNESDAY, THE APPROACHING UPPER TROUGH SHOULD  
ALLOW FOR THICKNESSES TO FALL ENOUGH FOR MORE OF A MIX OR A CHANGE  
OVER TO SNOW DURING THOSE PERIODS. POTENTIAL STILL EXISTS FOR SOME  
LIGHT ACCUMULATIONS OVER PARTS OF THE AREA TUESDAY NIGHT OR  
WEDNESDAY.  
 
GIVEN THE EXPECTED PRECIPITATION DURING THE PERIOD, WILL NARROW THE  
DIURNAL RANGE OF THE MOS GUIDANCE BY ABOUT 3-5 DEGREES FROM MONDAY  
ONWARD.  
 

 
 
   
LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)
 
 
ISSUED AT 307 PM EST SUN FEB 23 2020  
 
MODELS ARE CLOSE ENOUGH THAT THE NATIONAL BLEND OF MODELS  
INITIALIZATION WAS ACCEPTED FOR MOST ITEMS.  
 
A LARGE UPPER TROUGH WILL KEEP COLD CONDITIONS ACROSS CENTRAL  
INDIANA THROUGH MUCH OF THE LONG TERM PERIOD. SOME MODERATION WILL  
OCCUR NEXT SUNDAY.  
 
SOME LINGERING LIGHT SNOW IS POSSIBLE WEDNESDAY NIGHT BEFORE FORCING  
EXITS THE AREA. CAN'T RULE OUT SOME LIGHT PRECIPITATION AT TIMES  
AFTERWARD AS BOTH THE GFS AND ECMWF HAVE LIGHT PRECIPITATION AT  
DIFFERING TIMES WITH IMPULSES IN THE UPPER FLOW.  
 
HOWEVER, WITH VERY LOW CONFIDENCE WITH THESE FEATURES, WILL STICK  
WITH THE DRY NBM FORECAST FOR THURSDAY AND BEYOND.  
 

 
   
AVIATION (DISCUSSION FOR THE 232100Z TAF UPDATE)
 
 
ISSUED AT 321 PM EST SUN FEB 23 2020  
 
NO CHANGES NEEDED FOR KIND TAF.  
 
PREVIOUS DISCUSSION FOLLOWS...  
 
VFR CONDITIONS ARE EXPECTED THROUGH THE FIRST HALF OF THE PERIOD,  
THEN A QUICK DETERIORATION TO IFR AND BELOW WILL OCCUR.  
 
MID AND HIGH CLOUDS WILL INCREASE THROUGH THE FIRST HALF OF THE  
PERIOD AS A LOW PRESSURE SYSTEM APPROACHES THE AREA. AFTERWARD, A  
QUICK DETERIORATION TO IFR WILL OCCUR, WITH ALL SITES AT IFR BY 12Z.  
 
POOR FLYING CONDITIONS WILL THEN CONTINUE THROUGH THE REMAINDER OF  
THE TAF PERIOD AND BEYOND.  
 
RAIN WILL ARRIVE WITH THE LOWER CLOUDS.  
 

 
   
IND WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SYNOPSIS...JAS  
NEAR TERM...JAS  
SHORT TERM...JAS  
LONG TERM....50  
AVIATION...50  
 
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