Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 260837
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
337 AM CDT SUN JUL 26 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT SUN JUL 26 2015

08Z WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL RIDGE CENTERED OVER
WESTERN OK, WHILE A BROAD UPPER LEVEL TROUGH AND CLOSED LOW SAT OVER
BRITISH COLUMBIA. THERE WERE A COUPLE MCS ROUNDING THE TOP OF THE
UPPER RIDGE AND MOVING MAINLY INTO THE MID MS RIVER VALLEY. LOCALLY
THE ELEVATED CONVECTION APPEARS TO BE DRIVEN BY ISENTROPIC LIFT AND
SPEED CONVERGENCE FROM THE LOW LEVEL JET. SURFACE OBS SUGGEST THE
OLD OUTFLOW BOUNDARY WAS NEAR OR JUST SOUTH OF THE INTERSTATE 70
CORRIDOR.

THE MAIN FORECAST CHALLENGE IS TRYING TO FIGURE OUT IF MORNING
CONVECTION MAY THROW A WRENCH IN THE FORECAST LIKE YESTERDAY. MOST
OF THE HIGHER RESOLUTION MODEL SOLUTIONS SHOW THE ELEVATED
CONVECTION FALLING APART BY MID MORNING AS THE LOW LEVEL JET AND
ISENTROPIC LIFT WEAKENS. THIS SEEMS TO MAKE SOME SINCE AS THERE DOES
NOT APPEAR TO BE AN MCV OR VORT MAX ASSOCIATED WITH THIS ACTIVITY
THAT WOULD FORCE IT`S CONTINUATION LATE INTO THE DAY. THE ONLY WILD
CARD MAY THE MCS DIVING SOUTHEAST THROUGH IA. IF THIS SYSTEM, WITH A
BETTER DEFINED COLD POOL, WERE TO LAY DOWN AN OUTFLOW BOUNDARY THEN
PARTS OF NORTHEAST KS MAY END UP STAYING COOLER. BUT THIS SYSTEM
LOOKS TO CONTINUE MOVING SOUTHEAST. OTHERWISE THERE IS NO SIGNAL
FROM THE MODELS FOR CONTINUED PRECIP THROUGH THE DAY. THERE IS
EXPECTED TO BE A FAIR AMOUNT OF INSTABILITY WITH A HOT AND HUMID DAY
IN STORE ONCE AGAIN. BUT THERE DOESN`T APPEAR TO BE MUCH IF ANY
FORCING AS MID LEVEL HEIGHTS GRADUALLY RISE THROUGH THE DAY.
THEREFORE EXPECT GOOD INSOLATION BY THIS AFTERNOON WITH THE BOUNDARY
LAYER MIXING TO AROUND 875MB. THIS SHOULD YIELD AFTERNOON HIGHS IN
THE MID AND UPPER 90S. NORTH CENTRAL KS COULD SEE SOME LOWER
DEWPOINTS FROM THE AFTERNOON MIXING. NEVERTHELESS HEAT INDICES ARE
FORECAST TO BE AROUND 105 EVEN WITH SOME MODEST MIXING OF THE
DEWPOINTS. WITH THIS IN MIND, WILL MAINTAIN THE HEAD ADVISORY AS IS
FOR NOW AND MONITOR SHORT TERM TRENDS.

TONIGHT THE MODELS DEVELOP CONVECTION OFF THE HIGHER TERRAIN IN
NORTHERN CO AND WANT TO PROPAGATE IT EAST ALONG THE KS/NEB STATE
LINE. BOTH THE GFS AND NAM PROG A VORT MAX ASSOCIATED WITH THIS
CONVECTION MOVING INTO NORTH CENTRAL KS AND LOWERING HEIGHTS.
BECAUSE OF THIS THERE IS THE POTENTIAL FOR OVERNIGHT CONVECTION ONCE
AGAIN. SINCE MODELS WEAKEN THE CONVECTIVE COMPLEX BEFORE BRINGING IT
INTO EASTERN KS, HAVE KEPT POPS TONIGHT BELOW 20 PERCENT FOR EAST
CENTRAL KS THINKING CONVECTION MAY NOT BE ABLE TO MOVE THAT DEEP
INTO THE MID LEVEL RIDGE AXIS. LOWS ARE EXPECTED TO REMAIN MILD WITH
SOUTHERLY WINDS AND THE THERMAL RIDGE REMAINING TO THE WEST OF THE
FORECAST AREA. THINK LOWS WILL BE IN THE MID 70S FOR MOST AREAS
MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN JUL 26 2015

MONDAY THROUGH TUESDAY...THE UPPER RIDGE CENTERED OVER THE SOUTHERN
PLAINS WILL AMPLIFY ACROSS THE CENTRAL AND NORTHERN PLAINS SUNDAY
NIGHT INTO MONDAY AHEAD OF A MORE AMPLIFIED UPPER TROUGH MOVING INTO
THE THE WESTERN US SUNDAY NIGHT. THE AMPLIFIED UPPER RIDGE WILL THEN
BUILD NORTHEAST FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES STATES
AS THE AMPLIFIED UPPER LEVEL TROUGH LIFTS NORTHEAST INTO THE
NORTHERN HIGH PLAINS ON TUESDAY. THE BETTER CHANCES FOR
THUNDERSTORMS THROUGH THE PERIOD WILL REMAIN ACROSS NORTHWEST KS
NORTH AND EAST ACROSS NE. I CANNOT RULE OUT AN ISOLATED STORM DURING
THE NIGHT UNDER THE H5 RIDGE AXIS.

MONDAY MAY HAVE THE HIGHEST AFTERNOON HEAT INDICES AS SOUTHERLY 850MB
WINDS KEEP DEEP GULF MOISTURE IN PLACE ACROSS THE CWA. THE MIXING
MAY BE SLIGHTLY DEEPER ACROSS THE SOUTHWEST COUNTIES BUT
TEMPERATURES WILL WARM TO AROUND 100 DEGREES WITH DEWPOINTS IN THE
UPPER 60S. THE EASTERN COUNTIES WILL REACH INTO THE MID 90S BUT
DEWPOINTS WILL REMAIN IN THE MID TO UPPER 70S DURING THE AFTERNOON
HOURS. HEAT INDICES MONDAY AFTERNOON ACROSS THE CWA WILL RANGE FROM
104 TO 110.

ON TUESDAY THE LOW-LEVEL WINDS WILL VEER MORE TO THE SOUTHWEST
DURING THE AFTERNOON HOURS. THIS WILL LEAD TO DEEPER MIXING ALLOWING
DEWPOINTS ACROSS THE SOUTHWESTERN COUNTIES OF THE CWA MIXING DOWN
INTO THE MID 60S DURING THE AFTERNOON HOURS...THOUGH AFTERNOON HIGHS
MAY BE IN THE 100 TO 103 DEGREE RANGE. AFTERNOON HEAT INDICES
TUESDAY AFTERNOON MAY ONLY REACH THE 100 TO 104 DEGREE RANGE. THE
EASTERN HALF OF THE CWA MAY NOT SEE AS DEEP OF MIXING DURING THE
AFTERNOON HOURS WHICH WILL ALLOW AFTERNOON DEWPOINTS TO REMAIN IN
THE LOWER TO MID 70S. THUS, AFTERNOON HEAT INDICES WILL CONTINUE TO
RANGE FROM 103 TO 107 DEGREES.

TUESDAY NIGHT THROUGH THURSDAY...AN AMPLIFIED H5 TROUGH WILL MOVE
EAST ACROSS THE NORTHERN AND CENTRAL PLAINS INTO THE UPPER MIDWEST.
THIS WILL CAUSE A SURFACE COLD FRONT TO MOVE SOUTHEAST ACROSS THE
CWA LATE TUESDAY NIGHT AND THROUGH THE DAY WEDNESDAY. THERE WILL BE
STRONG ENOUGH ASCENT AHEAD OF THE THE H5 TROUGH AXIS, COMBINED WITH
SURFACE CONVERGENCE AHEAD OF THE FRONT FOR SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS NORTH CENTRAL KS LATE
TUESDAY NIGHT AND ACROSS THE REMAINDER OF THE CWA THROUGH THE DAY
WEDNESDAY AS THE SURFACE FRONT MOVES SOUTHEAST ACROSS THE CWA. POST
FRONTAL SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE NORTHERN
COUNTIES THROUGH HE AFTERNOON HOURS OF WEDNESDAY. THE FRONT WILL
MOVE SOUTHEAST OF THE CWA EARLY WEDNESDAY NIGHT BUT THERE WILL
REMAIN CHANCES FOR ELEVATED SHOWER AND THUNDERSTORMS NORTH OF THE
BOUNDARY...GENERALLY ALONG AND SOUTH OF I-70 THROUGH THURSDAY. HIGHS
WILL BE COOLER ON WEDNESDAY AND THURSDAY WITH LOWER TO MID 80S
EXPECTED ALONG THE NE BORDER TO NEAR 90 SOUTH OF I-35.

THURSDAY NIGHT THROUGH SATURDAY...A BROAD UPPER LEVEL RIDGE WILL
AMPLIFY ACROSS THE WEST CENTRAL US. THE CENTRAL AND SOUTHERN PLAINS
WILL BE ON THE EASTERN PERIPHERY OF THE UPPER RIDGE AXIS...THUS THE
WARMEST TEMPERATURES SHOULD REMAIN WEST OF THE CWA. HIGHS WILL ONLY
REACH THE UPPER 80S TO LOWER 90S THROUGH THE PERIOD.

THE ECMWF MODEL SHOWS THE THE H5 RIDGE ACROSS THE WEST CENTRAL US
EXPANDING EAST ACROSS THE SOUTHERN AND CENTRAL PLAINS. THEREFORE THE
HOT WEATHER MAY RETURN TO EASTERN KS INTO THE NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT JUL 25 2015

VFR EXPECTED OUTSIDE OF ANY CONVECTION THROUGH THE PERIOD.
SHRA AND TSRA WILL BE POSSIBLE AFTER 10Z THROUGH 16Z AND HAVE
INCLUDED VCTS IN TAFS DURING THIS PERIOD. WINDS LIGHT EAST TO BACK
TO THE SOUTH BY 15Z AROUND 8-10KTS, THEN DECREASE AFTER 02Z.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ008>012-020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...WOLTERS
LONG TERM...GARGAN
AVIATION...53



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