455  
FXUS63 KTOP 142349  
AFDTOP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TOPEKA KS  
649 PM CDT FRI AUG 14 2020  
   
..UPDATE TO AVIATION FORECAST DISCUSSION
 
 
   
SHORT TERM
 
(THIS EVENING THROUGH SATURDAY)  
ISSUED AT 256 PM CDT FRI AUG 14 2020  
 
THIS AFTERNOON, AN AMPLIFIED SHORTWAVE CONTINUES TO DIG INTO THE  
NORTHERN PLAINS WITH A LOW AMPLITUDE RIDGE OVER THE IMMEDIATE AREA  
AHEAD A SURFACE COLD FRONT NOW STRETCHED THROUGH PORTIONS OF CENTRAL  
AND SOUTHWESTERN NEBRASKA. WEAK PRE-FRONTAL SURFACE TROUGHING IS  
EVIDENT AHEAD OF THIS BOUNDARY WITH A FEW STORMS DEVELOPING THROUGH  
EASTERN NEBRASKA INTO SOUTH CENTRAL PORTIONS OF THE STATE. THIS  
ACTIVITY APPEARS TO BE AUGMENTED BY A VERY SUBTLE SHORTWAVE ALOFT  
WHICH IS MAINLY EVIDENT ON MID LEVEL WV IMAGERY CHANNELS.  
 
AS A RESULT OF THE INCOMING FRONTAL SYSTEM, CHANCES FOR SHOWERS AND  
STORMS - POSSIBLY A FEW SEVERE - WILL INCREASE OVER THE NEXT FEW  
HOURS INTO THE EVENING AND BE ENDING AROUND MIDNIGHT OR SHORTLY  
AFTER. TIMING AND OVERALL COVERAGE APPEAR TO BE THE MAIN QUESTIONS  
WITH ANY STORMS THIS EVENING. WEAK CONVERGENCE ALONG THE PREFRONTAL  
TROUGH AND IMMEDIATE COLD FRONT TRAILING BEHIND WILL HINGE ON WHAT  
TIME THE CAP/INHIBITION CAN WEAK SUFFICIENTLY FOR STORMS TO DEVELOP  
AND BE MAINTAINED WHILE INSTABILITY REMAINS HIGH. WEAK SHEAR  
APPEARS TO FAVOR SOME TYPE OF MULTICELL CLUSTER OR TWO WORKING  
THROUGH THE AREA ONCE STORMS CAN FORM. WITH THE INTENSE INSOLATION  
THIS AFTERNOON, THESE STORMS WOULD LIKELY POSE A DAMAGING WIND  
THREAT AND PERHAPS LARGE HAIL WITH THE MOST ROBUST UPDRAFTS. HEAVY  
RAIN IS ALSO A CONCERN BUT LIKELY TO REMAIN VERY LOCALIZED WITH  
QUESTION IN OVERALL COVERAGE. THE PROGRESSION OF THE FRONT SHOULD  
HELP WITH OVERALL STORMS MOVING ENOUGH SO THAT TRAINING EFFECTS  
WOUDLN'T BE A LARGE CONCERN. RIGHT NOW, NORTH CENTRAL KS CERTAINLY  
APPEARS TO HAVE THE GREATEST THREAT OF SEVERE STORMS, WHILE PORTIONS  
OF NORTHEAST KS COULD SEE SEE SEVERE STORMS BUT POINTS EAST OF  
MANHATTAN APPEAR TO BE LESS LIKELY WITH EACH PASSING HOUR AFTER  
SUNSET.  
 
A FEW SHOWERS COULD LINGER INTO THE EARLY MORNING HOURS MAINLY OVER  
PORTIONS OF CENTRAL KS AS WELL AS PORTIONS OF EASTERN KS WHERE SOME  
POST FRONTAL SHOWERS MAY STILL BE SUPPORTED BEFORE HIGH PRESSURE  
MORE COMPLETELY ENGULFS THE REGION.  
 
MODIFIED CANADIAN HIGH PRESSURE WILL CONTINUE TO EXPAND INTO THE AREA  
AS THE UPPER PATTERN TRANSITIONS TO A NORTHWEST FLOW REGIME OVER THE  
FORECAST AREA. THIS WILL RESULT IN AN EARLY FALL-LIKE WEEKEND WITH  
DEWPOINTS SIMILAR TO THAT OF A COUPLE WEEKS BACK. SHOULD BE VERY  
WELCOME AND LOOKS TO STICK AROUND FOR MUCH OF THE WEEK AHEAD.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 256 PM CDT FRI AUG 14 2020  
 
TRANSITIONING INTO THE LAST PART OF THE WEEKEND AND THE UPCOMING  
WEEK, AN AMPLIFYING WESTERN RIDGE SHOULD MEAN CONTINUED REINFORCED  
DRY AIR UNDER NORTHWEST FLOW. THIS WILL TEND TO KEEP DEWPOINTS LOW  
INTO THE UPPER 50S AND LOW 60S WITH HIGHS INTO THE 80S. AS A  
RESULT, VERY PLEASANT CONDITIONS HOLD WITH MINIMAL RAIN CHANCES  
OUTSIDE OF A FEW EARLY MORNING SHOWERS AS ISENTROPIC RESPONSES TAKE  
PLACE AND PERHAPS AN ILL TIMED WEAK EMBEDDED SHORTWAVE OR TWO SLIP  
DOWN THE EASTERN FLANK OF THE RIDGE.  
 
MEAN WESTERLIES RESIDE WILL TO THE NORTH WITH LIMITED ENERGY WORKING  
SOUTH OVER THE NEXT WEEK. SO, THE PATTERN SHOULD HOLD FOR A RATHER  
NICE WORK WEEK WITH HEAT INDEX VALUES HOLDING AROUND THE HIGH  
TEMPERATURES EACH DAY ALONG WITH LOWER OVERALL HUMIDITY.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 648 PM CDT FRI AUG 14 2020  
 
MAIN CHALLENGE FOR THIS PERIOD IS TIMING FRONTAL PASSAGE AND THE  
ASSOCIATED WINDS GUSTS, PRECIP, AND LOWERING CIGS. MAINTAINED VCTS  
AT KMHK THIS EVENING AS STORMS ARE LIKELY TO STAY TO THE WEST OF  
THE TERMINAL. POST-FRONTAL SHOWERS ARE POSSIBLE NEAR KTOP/KFOE  
OVERNIGHT BEFORE EXITING THE AREA SATURDAY MORNING. EXPECTING WIND  
GUSTS TO WEAKEN AND SKIES TO CLEAR THROUGH THE MORNING HOURS.  
 

 
   
TOP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...DRAKE  
LONG TERM...DRAKE  
AVIATION...FLANAGAN  
 
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