608  
FXUS63 KGID 201755  
AFDGID  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HASTINGS NE  
1255 PM CDT FRI JUL 20 2018  
   
UPDATE
 
 
ISSUED AT 949 AM CDT FRI JUL 20 2018  
 
HAVE UPDATED THE FORECAST TO INCREASE POPS FOR THE REST OF THE  
MORNING AND INTO THE EARLY AFTERNOON GIVEN RECENT DEVELOPMENT OFF  
TO OUR NW. THIS ACTIVITY APPEARS TO BE TIED TO A SUBTLE WAVE OVER  
CENTRAL NE, WITHIN THE NW FLOW, CAUSING WEAK WAA/ISENTROPIC LIFT  
(315K-320K LAYER). MODELS...FOR WHAT THEY'RE WORTH...INDICATE THE  
LEAST CAPPED INSTABILITY REMAINS ROOTED FAIRLY ELEVATED. 12Z LBF  
SOUNDING DID SHOW STEEP MID-LEVEL LAPSE RATES AS WELL AS  
UNSEASONABLY STRONG SHEAR, SO WILL HAVE TO WATCH FOR LARGE HAIL  
WITH THE STRONGEST CORES. BIGGEST QUESTION IS HOW LONG THIS  
ACTIVITY PERSISTS. CURRENT SHORT TERMS MODELS DON'T HAVE THE BEST  
HANDLE ON THE CURRENT ACTIVITY, BUT GENERALLY INDICATE A  
DECREASING TREND BY LATE AFTERNOON. GIVEN THE LOCATION AND SPEED  
OF THE SUBTLE WAVE THIS MAY HAVE SOME CREDENCE. HOWEVER,  
CONFIDENCE IS FAIRLY LOW AND I EXPECT MORE UPDATES WILL BE NEEDED.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 342 AM CDT FRI JUL 20 2018  
 
THE UPPER LEVEL PATTERN IS A RATHER TYPICAL NORTHWESTERLY FLOW  
REGIME OVER THE NORTHERN AND CENTRAL PLAINS WITH AN UPPER LEVEL  
RIDGE FROM TEXAS INTO THE DESERT SOUTHWEST. THIS WILL KEEP THE  
BULK OF THE EXTREME SUMMER HEAT WELL TO OUR SOUTH OVER OKLAHOMA  
AND TEXAS WITH GENERALLY BELOW NORMAL TEMPERATURES FOR OUR AREA  
NOT ONLY TODAY BUT LIKELY THROUGHOUT THE UPCOMING WEEK.  
 
SHOWER AND THUNDERSTORM CHANCES ARE LOW AT BEST WITH ONLY SUBTLE  
FORCING MECHANISMS WITHIN THE NORTHWESTERLY UPPER LEVEL FLOW  
PATTERN. THE 06Z NAM NEST IS THE MOST AGGRESSIVE WITH  
SHOWER/THUNDERSTORM DEVELOPMENT EARLY THIS AFTERNOON, BUT THIS  
MODEL OFTEN TENDS TO BE ONE OF THE MORE AGGRESSIVE MODELS WHEN IT  
COMES TO CONVECTION. MANY OF THE OTHER FORECAST MODELS ARE DRY.  
HAVE A FEELING THAT MOST AREAS WILL BE DRY TODAY, BUT LIKE  
YESTERDAY WE CAN NOT RULE OUT A FEW ISOLATED SHOWERS/THUNDERSTORMS  
PRIMARILY DURING THE AFTERNOON HOURS. ANY CONVECTION SHOULD  
QUICKLY WEAKEN WITH THE LOSS OF DIURNAL HEATING AS WE NEAR SUNSET.  
THE SPC HAS THE SOUTHWESTERN HALF OF OUR FORECAST AREA UNDER A  
MARGINAL SEVERE WEATHER RISK, WHICH GIVEN INSTABILITY AND SHEAR IS  
FEASIBLE IF WE DO GET ENOUGH FORCING FOR CONVECTION.  
   
LONG TERM
 
(SATURDAY THROUGH THURSDAY)  
ISSUED AT 342 AM CDT FRI JUL 20 2018  
 
THE UPPER LEVEL PATTERN WILL CONTINUE TO FEATURE A RIDGE ACROSS  
THE SOUTHWESTERN UNITED STATES AND A TROUGH OVER THE EASTERN  
UNITED STATES WITH OUR AREA UNDER A CONTINUED NORTHWESTERLY FLOW  
REGIME. THIS WILL KEEP OUR AREA COOLER THAN AVERAGE WITH HIGHS  
GENERALLY IN THE LOWER TO MID 80S ACROSS SOUTH CENTRAL NEBRASKA  
AND MID TO UPPER 80S OVER NORTH CENTRAL KANSAS. NORMAL HIGHS FOR  
THIS TIME OF YEAR ARE IN THE UPPER 80S OVER SOUTHERN NEBRASKA TO  
THE LOWER 90S OVER NORTHERN KANSAS. WE SHOULD SEE SEVERAL CHANCES  
FOR PRECIPITATION WITH THE JET STREAM DIPPING SOUTH INTO OUR  
FORECAST AREA AND WEAK SHORT WAVES PASSING THROUGH WITHIN THE  
NORTHWESTERLY FLOW PATTERN. AT THIS POINT, SUNDAY NIGHT AND  
TUESDAY NIGHT SEEM LIKE THE BETTER CHANCES FOR CATCHING SOME RAIN  
BASED ON THE TIMING OF SHORTWAVES PASSING THROUGH, BUT CONFIDENCE  
IN TIMING SUCH WEAK WAVES IN THIS PATTER IS FAIRLY LOW. ON THE  
OTHER HAND, CONFIDENCE IN BELOW NORMAL TEMPERATURES THROUGH THIS  
PERIOD IS RATHER HIGH.  
 

 
   
AVIATION
 
(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SATURDAY)  
ISSUED AT 1250 PM CDT FRI JUL 20 2018  
 
SIGNIFICANT WX: POSSIBLY AN ISO/BRIEF -TSRA, BUT CIG OR VSBY  
REDUCTION UNLIKELY  
 
REST OF TODAY THRU 00Z: ISO SHWRS/STMS REMAIN POSS INTO  
AFTERNOON, WITH BEST/LONGEST CHC AT GRI. HAVE GONE VCTS FOR NEXT  
FEW HOURS. THIS ACTIVITY IS HIGH BASED (CIGS ABOVE 10K FT) SO ANY  
FLIGHT CAT RESTRICTIONS ARE UNLIKELY. WIND WILL BE LGT OUT OF  
E/ESE.  
 
TONIGHT: VFR. CLEARING SKIES WITH WINDS BECOMING LGT AND VRBL  
AROUND SUNSET.  
 
SAT THRU 18Z: VFR. CLEAR OR MOSTLY CLEAR SKIES. WINDS REMAIN LGT  
AND VRBL OR PERHAPS E/ESE  
 

 
   
GID WATCHES/WARNINGS/ADVISORIES
 
 
NE...NONE.  
KS...NONE.  

 
 

 
 
UPDATE...THIES  
SHORT TERM...WESELY  
LONG TERM...WESELY  
AVIATION...THIES  
 
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