701  
FXUS63 KOAX 180426  
AFDOAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE  
1126 PM CDT THU SEP 17 2020  
   
..UPDATED FOR 06Z AVIATION FORECAST DISCUSSION
 
 
   
DISCUSSION
 
 
ISSUED AT 319 PM CDT THU SEP 17 2020  
 
FORECAST SUMMARY:  
 
A CONTINUATION OF RELATIVELY TRANQUIL WEATHER IS IN THE FORECAST FOR  
THE NEXT WEEK. GRADUALLY WARMING TEMPERATURES WILL TAKE US THROUGH  
THE END OF SUMMER AND PAST THE AUTUMNAL EQUINOX ON TUESDAY.  
PRECIPITATION CHANCES WILL BE SPOTTY AT BEST.  
 
TONIGHT THROUGH THURSDAY:  
 
MAIN UPPER AIR PATTERN FEATURES A DEEP TROUGH TO OUR EAST, EXTENDING  
FROM HUDSON BAY INTO THE EASTERN CONUS, WHICH IS FORECAST TO DEEPEN  
FRIDAY BEFORE LIFTING NORTHEAST. TO OUR WEST, ANOTHER UPPER  
LOW/TROUGH WAS MOVING TOWARD THE PACIFIC NORTHWEST, AND IS EXPECTED  
TO SWING THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS  
THIS WEEKEND. IN BETWEEN, WE'LL SEE ONE MORE DAY UNDER THE INFLUENCE  
OF THE EASTERN TROUGH BEFORE HEIGHTS BEGIN TO RISE FOR THE WEEKEND  
AHEAD OF APPROACHING WESTERN TROUGH.  
 
THAT TROUGH WILL MOST LIKELY AFFECT OUT WEATHER SOMETIME SUNDAY INTO  
SUNDAY NIGHT WHEN SHORTWAVE EXTENDING SOUTH THROUGH THE WESTERN  
DAKOTAS INTO WESTERN NEBRASKA PIVOTS NORTHEAST. ASSOCIATED SURFACE  
FRONTAL SYSTEM IS STILL ADVERTISED BY CONSENSUS MODEL OUTPUT TO  
REMAIN JUST WEST OF OUR AREA, KEEPING MAINLY SOUTHERLY LOW LEVEL  
FLOW IN PLACE. HOWEVER MID LEVEL WARM ADVECTION/LIFT MAY BE ENOUGH  
TO OVERCOME RELATIVELY DRY ATMOSPHERE TO PRODUCE A FEW SHOWERS  
SUNDAY OR SUNDAY NIGHT. OTHERWISE PRECIPITATION CHANCES WILL BE HARD  
TO COME BY THROUGH THE MIDDLE OF NEXT WEEK.  
 
TEMPERATURES ON FRIDAY SHOULD HOLD IN THE LOWER 70S MOST AREAS AS  
COOLER AIRMASS REMAINS OVERHEAD. MODERATELY THICK SMOKE LAYER ALOFT  
IS FORECAST TO REMAIN OVER THE AREA AT LEAST INTO SATURDAY AS MID  
LEVEL FLOW TAKES SMOKE NORTH FROM THE WESTERN STATES THEN SOUTHEAST  
INTO THE PLAINS. WHEN SMOKE LAYER HAS BEEN THICKEST WE HAVE SEEN  
TEMPERATURES LEVELING OFF IN THE HEAT OF THE DAY WITH HIGHS  
AVERAGING SEVERAL DEGREES LOWER THE CONSENSUS MODEL OUTPUT. WOULD  
EXPECT THAT SAME SCENARIO FRIDAY AND SATURDAY GIVEN HRRR-SMOKE MODEL  
OUTPUT. HOWEVER UPWARD TREND OF TEMPERATURES STILL PUTS HIGHS BACK  
INTO THE MID TO UPPER 70S SATURDAY BEFORE WARMING FURTHER INTO THE  
MIDDLE 80S BY TUESDAY AND WEDNESDAY OF NEXT WEEK. CONFIDENCE ON  
AREAL EXTENT AND THICKNESS OF SMOKE LAYER LOWERS SIGNIFICANTLY AS WE  
GET PAST 48 HOURS OF THE FORECAST, SO WILL HAVE TO BE CONSIDERED  
WITH EACH PACKAGE. IF INFLUENCE IS STILL INTACT NEXT WEEK, EXPECT  
HIGHS TO BE SEVERAL DEGREES COOLER.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)  
ISSUED AT 1130 PM CDT THU SEP 17 2020  
 
CLOUDS WITH BASES FL050 TO FL100 WILL BE POSSIBLE OVERNIGHT AND  
INTO AT LEAST LATE FRIDAY MORNING. AMOUNTS WILL VARY FROM SCT TO  
BKN. SOME PATCHY FOG IS POSSIBLE LATE TONIGHT, BUT OTHERWISE  
EXPECT VFR CONDITIONS. SMOKE ALOFT IS UP TO AS HIGH AS FL200, BUT  
ABOVE THAT THERE IS NOT MUCH SMOKE. WINDS WILL BE UNDER 10 KNOTS  
OVERNIGHT, AND THEN INCREASE TO AROUND 10 KNOTS OR SO FRIDAY.  
WINDS MAY BE A BIT STRONG AT KOFK TOMORROW BY NOON, IN THE 10 TO  
15 KNOT RANGE.  
 

 
   
OAX WATCHES/WARNINGS/ADVISORIES
 
 
NE...NONE.  
IA...NONE.  

 
 

 
 
DISCUSSION...DERGAN  
AVIATION...MILLER  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab NE Page
The Nexlab IA Page Main Text Page