322
FXUS63 KTOP 090806
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
306 AM CDT WED JUL 9 2025
KEY MESSAGES
- THERE IS A 20-30% CHANCE FOR SHOWERS AND STORMS TO MOVE
TOWARDS THE AREA FROM THE NORTHWEST OVERNIGHT TONIGHT.
CONFIDENCE IN SEVERE POTENTIAL IS LOW.
- HOT WEATHER IS EXPECTED THROUGH THE END OF THE WORKWEEK. HIGHS
THURSDAY SHOULD REACH THE MIDDLE AND UPPER 90S.
- BETTER CHANCES FOR SHOWERS AND STORMS IS EXPECTED FOR FRIDAY.
- A BREAK FROM THE HOT WEATHER IS FORECAST FOR SATURDAY WITH
HIGHS HOLDING IN THE MIDDLE 80S.
DISCUSSION
ISSUED AT 306 AM CDT WED JUL 9 2025
07Z WATER VAPOR IMAGERY SHOWED THE UPPER RIDGE STILL OVER AZ
WHILE THE MEAN WESTERLIES REMAIN WELL NORTH ACROSS THE CANADIAN
PLAINS. SURFACE OBS SHOWED BROAD HIGH PRESSURE CENTERED OVER THE
UPPER MIDWEST WITH A GENERAL SOUTHERLY TO SOUTHEASTERLY LOW
LEVEL WIND FIELD FROM THE SOUTHERN PLAINS INTO THE CENTRAL HIGH
PLAINS.
THE FORECAST IS OF LOW CONFIDENCE DUE TO THE NATURE OF THE
ENVIRONMENT. MODELS CONTINUE TO SHOW A WEAKLY FORCED SYNOPTIC PATTERN
WITH A CONDITIONALLY UNSTABLE AIRMASS IN PLACE. SO SOMETHING LIKE
MODEST LOW LEVEL CONVERGENCE OR A CONVECTIVELY INDUCED MCV COULD
SPARK SHOWERS AND THUNDERSTORMS. UNFORTUNATELY THESE FEATURES ARE NOT
WELL HANDLED WITH THE MODELS. SO HAVE TRIED TO PUT TOGETHER THE MOST
LIKELY SCENARIO FOR THE FORECAST. FIRST OFF THERE IS LITTLE OR NO
CONFIDENCE IN THE NAM SOLUTION WHICH APPEARS TO CONTINUE TO SUFFER
FROM CONVECTIVE FEEDBACK IN THE MODEL. YESTERDAY THE NAM HAD A VORT
MAX COMING OUT OF THE CENTRAL HIGH PLAINS THIS MORNING IMPACTING THE
FORECAST AREA. AND MUCH OF THE CONVECTION INSTEAD HAS BEEN OVER THE
SOUTHERN HIGH PLAINS. THERE IS A SMALL CLUSTER OF CONVECTION OVER
SOUTH CENTRAL SD THAT COULD PROVIDE A MCV FOR LATER CONVECTION. BUT
THE CHANCES OF IT REACHING THE FORECAST AREA ARE A LITTLE TO LOW TO
INCLUDE IN THE FORECAST AT THIS TIME. SO STARTED OUT TODAY WITH A
DRY FORECAST. THERE HAS BEEN A SIGNAL FROM THE HRRR THE PAST COUPLE
RUNS OF STORMS DEVELOPING THIS AFTERNOON OVER THE WY HIGH PLAINS AND
MAKING A RUN AT THE FORECAST AREA OVERNIGHT. THE ONLY OTHER CAMS
SHOWING A SIMILAR IDEA IS THE TWO MPAS MODELS. SO HAVE SOME 20 TO 30
PERCENT CHANCE POPS IN THE FORECAST TO ACCOUNT FOR THIS. THE ONLY
OTHER CHANGE TO THE FORECAST THIS MORNING WAS TO ADD SOME PATCHY FOG
TO LOW LYING AREAS. CALM WINDS AND CLEAR SKIES MAY ALLOW FROM SOME
RADIATIONAL FOG TO DEVELOP. I WOULDN'T EXPECT THIS TO LINGER MUCH
PAST 8AM.
THERE ARE TWO FRONTAL BOUNDARIES PROGGED BY THE MODELS THAT SHOW A
BETTER SIGNAL FOR ORGANIZED PRECIPITATION. THE FIRST BOUNDARY LOOKS
TO MOVE INTO THE AREA EARLY FRIDAY, WHICH IS A SLOWER TREND FROM THE
BLEND THAN A COUPLE DAYS AGO. AS A RESULT THE POPS HAVE BEEN LOWERED
FOR THE DAYTIME HOURS THURSDAY AND SHIFTED WEST FOR THURSDAY NIGHT.
THE DAY2 OUTLOOK SHOWS A SLIGHT RISK FOR THE NORTHWEST CORNER OF THE
FORECAST AREA. BASED ON THE TIMING OF THE BOUNDARY AND MODELS
SHOWING BULK SHEAR REMAINING BETWEEN 20 AND 30KT, THE RISK MAY END
STAYING WEST OF THE FORECAST AREA. THE NAM APPEARS TO BE SHOWING
IT'S MOIST BIAS IN BOUNDARY LAYER MOISTURE AND DEVELOPING HIGH CAPE
VALUES, AND SO I TAKE THAT PROG WITH A GRAIN OF SALT. BUT EVEN THEN
SURFACE BASED INHIBITION IS PROGGED TO BE INCREASING DURING THE
OVERNIGHT PERIOD. FOR FRIDAY, HAVE STAYED WITH THE BLEND FORECAST
WHICH HAS POPS RANGING FROM 40 TO 60 PERCENT. THIS SEEMS REASONABLE
AT THIS TIME FRAME. DEPENDING ON WHEN STORMS DEVELOP AND HOW MUCH
DESTABILIZATION CAN OCCUR, THERE MAIN BE SOME RISK FOR SEVERE STORMS
THROUGH THE AFTERNOON AND EVENING.
THE SECOND FRONTAL BOUNDARY IS PROGGED TO INFLUENCE THE WEATHER ON
TUESDAY OF NEXT WEEK AND THE NBM HAS CHANCE POPS FOR THIS. OUTSIDE
OF THESE TWO SYNOPTIC FORCING MECHANISMS ANY LITTLE MESOSCALE
FEATURE (OR LACK OF ONE) COULD ALTER THE FORECAST. SO LOW END POPS
ARE SPREAD THROUGH THE FORECAST.
TEMPS ARE FORECAST TO HEAT UP TODAY AND THURSDAY AS THE THERMAL
RIDGE BUILDS INTO CENTRAL KS. HEAT INDICES ARE FORECAST TO REMAIN
BELOW 103 THURSDAY AFTERNOON WITH SOME MIXING OF THE DEWPOINT TEMPS.
THE HEAT RISK AND WBGT ARE MARGINAL FOR A HEAT ADVISORY AS WELL. BUT
IT MAY BE WORTH CONSIDERING IF TEMPS ARE FORECAST TO GET A LITTLE
HOTTER. THE BRIGHT SPOT IN THE FORECAST IS ON SATURDAY WHEN SURFACE
HIGH PRESSURE PUSHES THE BOUNDARY AND LIKELY PRECIP CHANCES SOUTH.
IT SHOULD ALSO BRING A TEMPORARY REPRIEVE FROM THE 90S WITH HIGHS
FORECAST TO HOLD IN THE MIDDLE 80S.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1216 AM CDT WED JUL 9 2025
CONFIDENCE IN MODEL SOLUTIONS OF CONVECTION IS PRETTY LOW GIVE
POOR CONTINUITY AND THE NAM'S PROPENSITY FOR DEVELOPING
CONVECTIVE FEEDBACK INDUCED VORT MAXIMUM. UNLESS SOMETHING BLOWS
UP ACROSS THE NEB PANHANDLE SOON, THINK THE ODDS OF THE
TERMINALS STAYING DRY ARE PRETTY GOOD. THERE ARE SOME STORMS
OVER SOUTHWEST SD THAT I WILL BE KEEPING AN EYE ON. BUT FOR NOW
WILL KEEP A VFR FORECAST GOING WITH JUST SOME MID CLOUDS THROUGH
THE DAY.
TOP WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...WOLTERS
AVIATION...WOLTERS
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