489  
FXUS63 KOAX 181750  
AFDOAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE  
1150 AM CST SAT NOV 18 2017  
   
SHORT TERM
 
(TODAY THROUGH MONDAY)  
ISSUED AT 255 AM CST SAT NOV 18 2017  
 
PRECIPITATION ENDING THIS MORNING, CLOUD COVER TODAY AND  
TEMPERATURES THE NEXT FEW DAYS WILL PROVIDE THE MAIN FORECAST  
CHALLENGES.  
 
TWO MAIN JET SEGMENTS WERE NOTED AT 00Z ON THE 300 MB CHART. ONE  
EXTENDED FROM ND INTO NORTHERN MN (120-125 KNOTS) AND ANOTHER WAS  
PUNCHING EAST FROM CO. AT 500 MB, STRONGEST HEIGHT FALLS WERE OVER  
ONTARIO CANADA, BUT VALUES OF 50 METERS OR MORE EXTENDED DOWN AS  
FAR AS NM AND NORTH TX. MODEST THERMAL GRADIENT WAS IN PLACE AT  
700 MB, AND UPPER LEVEL DYNAMICS WERE ACTING ON THIS TO PRODUCE  
MID LEVEL FRONTOGENESIS. AT THE SURFACE, LOW PRESSURE WAS OVER  
EASTERN KS, WHILE A COLD FRONT TRAILED FROM NEAR CHICAGO TO NEAR  
KANSAS CITY AND THEN TO NORTH OF AMARILLO.  
 
A COUPLE OF FRONTOGENETICALLY FORCED BANDS OF PRECIPITATION HAVE  
AFFECT THEN AREA, AND AS OF AROUND 215 AM THE MOST PROMINENT BAND  
STRETCHED FROM AROUND GRAND ISLAND TO WAHOO, OMAHA AND HARLAN  
IOWA. HEAVIEST PRECIPITATION SHOULD BE ALONG AND SOUTH OF  
INTERSTATE 80 THROUGH MID MORNING, DECREASING FROM NORTH TO SOUTH  
WITH TIME. SNOW ACCUMULATIONS DO NOT SEEM LIKELY, ALTHOUGH THERE  
WILL PROBABLY BE A RAIN/SNOW MIX AT TIMES. SOME LOW LEVEL CLOUDS  
MAY LINGER WELL BEHIND THE PRECIPITATION SHIELD, AS NOTED BY  
RECENT RAP MODEL OUTPUT. EXPECT SUNNY TO PARTLY CLOUDY SKIES BY  
THE AFTERNOON FOR MOST OF THE FORECAST AREA.  
 
NORTH/NORTHWEST WINDS WILL BE SOMEWHAT GUSTY TODAY, BUT WILL  
DECREASE THIS EVENING. TONIGHT, WINDS TURN MORE TO THE WEST AS  
SURFACE RIDGE AXIS BUILDS EAST ACROSS THE REGION. LOWS SHOULD DROP  
INTO THE LOWER AND MID 20S, DESPITE WEAK WARM AIR ADVECTION LATE  
TONIGHT. LOOK FOR DRY CONDITIONS SUNDAY AND MONDAY WITH HIGHS IN  
MOSTLY IN THE LOWER AND MID 50S SUNDAY, THEN MID TO UPPER 50S ON  
MONDAY.  
   
LONG TERM
 
(MONDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 255 AM CST SAT NOV 18 2017  
 
A MAINLY DRY PATTERN IS FORECAST THROUGH THE WEEK, WITH MODELS IN  
GOOD AGREEMENT THAT A 500 MB RIDGE WILL BUILD OVER THE ROCKIES.  
THERE ARE SOME WEAK SIGNALS FOR LIGHT PRECIPITATION FROM BOTH  
THE 00Z RUNS OF THE GFS AND ECMWF BY FRIDAY NIGHT INTO SATURDAY.  
THAT WILL BE ASSOCIATED WITH A TROUGH MOVING ACROSS THE REGION  
FROM THE NORTHWEST.  
 
TUESDAY AND WEDNESDAY WILL BE NOTICEABLY COOLER THAN MONDAY.  
THURSDAY AND FRIDAY EXPECT HIGHS MAINLY IN THE 50S, WITH SOME  
LOWER 60S POSSIBLE FRIDAY.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)  
ISSUED AT 1150 AM CST SAT NOV 18 2017  
 
VFR CONDITIONS WILL PREVAIL THROUGH MOST OF THE PERIOD WITH  
NORTHWEST WINDS DIMINISHING BY 00Z. HIGH PRESSURE WILL BUILD INTO  
THE AREA OVERNIGHT WITH WINDS BECOMING LIGHT. A PERIOD OF MVFR  
CIGS IS POSSIBLE THROUGH 22Z AS AREA OF LOW LEVEL MOISTURE OVER  
SOUTHEAST SOUTH DAKOTA DROPS SOUTHEAST THIS AFTERNOON.  
 

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

 
 

 
 
SHORT TERM...MILLER  
LONG TERM...MILLER  
AVIATION...FOBERT  
 
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