583  
FXUS63 KTOP 240441  
AFDTOP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TOPEKA KS  
1141 PM CDT WED MAY 23 2018  
   
..UPDATE TO AVIATION FORECAST DISCUSSION
 
 
   
DISCUSSION
 
(TONIGHT THROUGH WEDNESDAY)  
ISSUED AT 1119 PM CDT WED MAY 23 2018  
 
THE OVERALL SYNOPTIC PATTERN WILL CHANGE LITTLE OVER THE COURSE  
OF THE NEXT WEEK WITH WELL ABOVE NORMAL TEMPERATURES AND PERIODIC  
CHANCES FOR SHOWERS AND STORMS.  
 
THE EARLY AFTERNOON SYNOPTIC SETUP FEATURED AN AMPLIFIED UPPER  
TROPOSPHERIC RIDGE AXIS CENTERED ALONG THE MISSISSIPPI RIVER  
VALLEY. A REX BLOCK WAS IN THE PROCESS OF BREAKING DOWN OVER THE  
WESTERN CONUS WITH THE WEAK AND COMPLEX LOW OVER MONTANA/WYOMING  
LIFTING NORTHWARD INTO SOUTHERN CANADA. BROAD, WEAK SOUTH TO  
SOUTHWESTERLY FLOW COULD BE FOUND OVER NE KANSAS WITH H850 TEMPS  
OF +17 TO +19 C AND SURFACE HIGHS APPROACHING 90 DEGREES IN MANY  
LOCATIONS. DEWPOINTS MORE TYPICAL OF JUNE AND JULY WERE IN PLACE  
OWING TO AN OPEN GULF, WITH VALUES IN THE 60S TO LOW 70S AT TIMES.  
 
ISOLATED SHOWERS AND STORMS DEVELOPED NEAR EMPORIA MIDDAY ALONG A  
VERY WEAK RIBBON OF 305-310K ISENTROPIC UPGLIDE COINCIDENT WITH  
1500- 2500 J/KG OF MLCAPE AND MINIMAL CINH, BUT GIVEN THE  
NEGLIGIBLE DEEP SHEAR PROFILES, THESE PULSE STORMS QUICKLY  
COLLAPSED. HOWEVER, THE RESIDUAL CONVECTIVE PERTURBATIONS/OUTFLOW  
BOUNDARIES MAY SERVE FOR ADDITIONAL THUNDERSTORM DEVELOPMENT  
THROUGHOUT THE COURSE OF THE AFTERNOON--WANING THIS EVENING AFTER  
PEAK HEATING. HOWEVER, AS WITH EARLIER CONVECTION, THE FACT THAT  
WINDS ARE 20 KTS OR LESS THROUGH THE ENTIRE TROPOSPHERE WILL  
HINDER ORGANIZATION AND LONGEVITY. A STRAY DOWNBURST WOULD BE THE  
MAIN THREAT WITH ANY STORM.  
 
CONVECTION HAS STARTED REDEVELOPING WITH A REMNANT MCV OVER  
NORTON AND GRAHAM COUNTIES IN NORTH CENTRAL KS EARLY THIS  
AFTERNOON. THE HRRR HAS BEEN PEGGING THIS DEVELOPMENT WITH ITS  
LAST FIVE RUNS AND TRACKS IT EASTWARD ALONG THE KS/NE BORDER  
BEFORE IT DECAYING AT SUNSET. HAVE LEVERAGED THE TIME-LAGGED HRRR  
FOR POPS IN THE NW THIS EVENING TO ACCOUNT FOR THIS POSSIBILITY.  
 
AS THE CUTOFF LOW OVER THE WESTERN CONUS EJECTS INTO SW CANADA  
TONIGHT, A TRAILING SHORTWAVE DRAGS EASTWARD OVER THE HIGH PLAINS  
ON THURSDAY. A FEW CAMS MAINTAIN SOME REFLECTION OF OVERNIGHT HIGH  
PLAINS CONVECTION INTO NORTHEAST KS THU MORNING, BUT CONFIDENCE  
IN THIS SOLUTION IS NOT VERY HIGH. ADDITIONAL PEAK HEATING SHOWERS  
AND STORMS ARE POSSIBLE THURSDAY AFTERNOON WITH A BETTER CHANCE  
FOR STORMS ON THURSDAY NIGHT/FRIDAY MORNING AS A THUNDERSTORM  
COMPLEX OVER SOUTHERN NEBRASKA ADVANCES SOUTHEASTWARD WITH THE  
UPPER LEVEL TROUGH. AS WITH CONVECTION THE PREVIOUS TWO DAYS, THE  
LACK OF DEEP SHEAR THROUGH THE COLUMN WILL LIMIT ORGANIZATIONAL  
POTENTIAL AND RESULT IN NEW CONVECTION BEING FORCED ON THE  
ADVANCING COLD POOL. THERE REMAINS A MODEST AMOUNT OF MUCAPE IN  
PLACE AND A STRENGTHENING LLJ TO SUPPORT CONVECTION THROUGH THE  
OVERNIGHT HOURS AND INTO FRIDAY MORNING AS THE LINE MOVES THROUGH  
NE KANSAS. LARGE HAIL AND POTENTIALLY GUSTY WINDS WOULD BE THE  
MAIN IMPACTS.  
 
AS WE ROLL INTO THE HOLIDAY WEEKEND, THE MAIN THEME WILL BE THE  
CONTINUED SUMMERTIME HEAT AND HUMIDITY. H850 TEMPS INCREASE TO +20  
TO +24 C BY FRIDAY MORNING AND PERSIST WELL INTO NEXT WEEK AS A  
NEW CUTOFF LOW BECOMES ESTABLISHED OVER THE WESTERN CONUS. THIS  
WILL TRANSLATE INTO SURFACE HIGHS IN THE LOW 90S THROUGHOUT THE  
ENTIRE FORECAST PERIOD. WEAK SOUTHERLY FLOW WILL SUSTAIN THE GULF  
MOISTURE PLUME ALREADY ANCHORED OVER EASTERN KANSAS. CONTINUED  
ILL-TIMED CHANCES FOR PULSE SHOWERS AND STORMS WILL ALSO PERSIST  
THROUGH THE WEEKEND, WITH THE NEXT DECENT CHANCE OF A MORE  
ORGANIZED STORM THREAT NOT COMING UNTIL TUESDAY NIGHT AS THE  
CUTOFF LOW DEVOLVES INTO A WAVE AND EJECTS ENE.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)  
ISSUED AT 1119 PM CDT WED MAY 23 2018  
 
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THERE REMAINS A  
CHANCE FOR ISOLATED TO SCATTERED STORMS TO FORM TOMORROW AFTERNOON  
NEAR TERMINALS BUT PREDICTABILITY IS STILL TOO LOW TO MENTION IN  
THIS TAF ISSUANCE.  
 

 
   
TOP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
DISCUSSION...SKOW  
AVIATION...HELLER  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab KS Page Main Text Page