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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