Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KTOP 041804
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
104 PM CDT TUE AUG 4 2015

...UPDATE TO AVIATION FORECAST DISCUSSION...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT TUE AUG 4 2015

CONVECTION THIS MORNING ONGOING JUST TO THE NORTH AND EAST OF THE
FORECAST AREA...FOLLOWING WHAT IS LIKELY THE BETTER CONVERGENCE OF
THE LOW LEVEL JET AND LIFT ALONG THE 305K SURFACE.  SURFACE FRONTAL
BOUNDARY IS SETTLED GENERALLY FROM NW TO SE ALONG THE I70 CORRIDOR.

MOST GUIDANCE SUGGESTS CURRENT AREA OF CONVERGENCE STAYS JUST TO THE
NORTH OF THE AREA...BUT WILL KEEP SOME SLIGHT CHANCES ALONG THE NE
BORDER THIS MORNING WHERE ITS POSSIBLE OUTFLOW MAY BE ENOUGH TO
OVERCOME WEAK CAPPING THAT FAR NORTH.  REST OF THE AREA WILL LIKELY
HAVE TO WAIT UNTIL LATER THIS AFTERNOON WHEN UPPER WAVE CURRENTLY
OVER WESTERN KANSAS MAKES ITS WAY EASTWARD.  THINK THERE WILL BE
ENOUGH TIME FOR SUNSHINE TO BUILD UP INSTABILITY TO THE 1000-1500
J/KG RANGE...BUT SHEAR IS WEAK AND STILL THINK SLOW MOVING STORMS
AND LOCALLY HEAVY RAIN IS THE MOST LIKELY HAZARD FROM THESE
STORMS...ALTHOUGH COULD SEE SOME GUSTY WINDS EARLY AS STORMS COME IN
OVER A HEATED UP LATE MORNING AIR MASS. BETTER RAIN CHANCES MOVE
ACROSS THE SOUTH AND INTO THE EAST LATER THIS EVENING AND OVERNIGHT.
DAYTIME HIGHS IN THE 80S MAY BE SLIGHTLY COOLER OUT WEST IF THE RAIN
GETS IN FASTER...WITH NIGHTTIME LOWS FROM THE MIDDLE TO UPPER 60S
TONIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM CDT TUE AUG 4 2015

PERIODS OF MOST CONCERN LOOK TO BE WEDNESDAY AND WEDNESDAY NIGHT.
CONVECTION WILL LIKELY LINGER AND REFIRE INTO THE DAYTIME HOURS OF
WEDNESDAY WITH UPPER WAVE STILL MAKING ITS WAY THROUGH AND RATHER
IMPRESSIVE UPPER FLOW, THERMAL GRADIENT, AND THUS ISENTROPIC LIFT
FOR LATE SUMMER. SPECIFIC TRENDS IN CONVECTION REMAIN UNCLEAR, BUT
AT LEAST A FEW AREAS OF HEAVY RAIN SEEM POSSIBLE IN NORTHWEST FLOW
AND SYNOPTIC BOUNDARY OF SIMILAR ORIENTATION. THERE WILL ALSO BE
SOME POTENTIAL FOR SEVERE STORMS IF A MID-LATE DAY BREAK CAN OCCUR
FOR MAINLY EASTERN LOCATIONS. IF DECENT BOUNDARY LAYER MIXING CAN
BECOME ESTABLISHED, CAPE/SHEAR COMBO WOULD EASILY SUPPORT SUPERCELL
STORMS WITH IMPRESSIVE WIND FIELDS OVER THE THE 5000-15000 FOOT
LAYER. UPPER TROUGH`S PASSAGE WEDNESDAY NIGHT SHOULD KEEP MUCH OF
THE NEXT PERIOD OR TWO DRY. EXACT TEMPS WILL LARGELY DEPEND ON
PRECIP TRENDS WITH SREF T SPREAD AROUND 7 DEGREES.

NEXT WAVE IN THE NORTHWEST FLOW BRINGS ANOTHER MODEST BOUNDARY
THROUGH THE AREA THURSDAY EVENING WITH FLOW OVER THE BOUNDARY
DEVELOPING BY FRIDAY NIGHT, AND LIKELY STAYING NEAR TO NOT FAR SOUTH
OF THE AREA INTO EARLY NEXT WEEK IN STAGNANT LARGE SCALE REGIME. WILL
CONTINUE SMALL THUNDERSTORM CHANCES FOR SEVERAL PERIODS WITH A
SLIGHT WARMING TREND GIVEN NO CERTAIN DAY TO EXPECT PRECIP AT THIS
POINT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1250 PM CDT TUE AUG 4 2015

FORECAST PERIOD SHOULD BE ACTIVE AT TIMES, BUT NOT EXPECTING A
TOTAL WASHOUT OVER THE TERMINALS. THINKING IS THAT LATER THIS
AFTERNOON WITH SOME HEATING AND ADDITIONAL FORCING ALOFT COUPLED
WITH SEVERAL BOUNDARIES OVER OR NEAR THE TERMINALS, THAT A DECENT
CHANCE FOR THUNDERSTORMS SHOULD SET UP AND LAST UNTIL LATE
EVENING. THE EARLY MORNING SHOULD SEE A LULL IN ACTIVITY AND THEN
BY AROUND 10-12Z ANOTHER WAVE MAY MAKE ITS WAY INTO THE REGION
WHICH COULD BRING ABOUT THE CHANCE FOR MORE STORMS WHICH ALSO MAY
BRING CIG/VIS INTO THE IFR CATEGORY. HAVE NOT BEEN THAT
PESSIMISTIC WITH THIS ISSUANCE. DEPENDING ON HOW ACTUAL FEATURES
DEVELOP AND TRACK, THEN THERE WILL LIKELY BE SOME CHANGES TO THIS
FORECAST.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...67
LONG TERM...65
AVIATION...DRAKE


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.