Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 012353
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
653 PM CDT WED JUL 1 2015

...UPDATE TO AVIATION FORECAST DISCUSSION...

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 255 PM CDT WED JUL 1 2015

LATEST SATELLITE SHOWS A MID LEVEL SHORTWAVE MOVING SOUTHEAST ACROSS
SOUTHEAST NEBRASKA INTO NORTHEAST KANSAS AT 20Z. ELEVATED SHOWERS
WERE MOVING ACROSS EAST CENTRAL KANSAS ON THE EDGE OF THE EML IN THE
FAR EAST. SCATTERED ELEVATED SHOWERS HAVE CONTINUED ACROSS THE
SOUTHWEST COUNTIES FROM COUNCIL GROVE TO SOUTH OF BURLINGTON. LATEST
SURFACE ANALYSIS SHOWS A SURFACE LOW IN CENTRAL KANSAS WITH A
BOUNDARY EXTENDING EASTWARD ALONG AND TO THE SOUTH OF INTERSTATE 70.
LATEST HRRR SEEMS TO HAVE A HANDLE ON THE CURRENT SHOWER ACTIVITY
AND BEGINS TO BREAK OUT CONVECTION GENERALLY ALONG AND SOUTHEAST OF
A LAWRENCE TO EMPORIA LINE BETWEEN 21Z-AND 23Z. EFFECTIVE SHEAR OF
40 TO 50 KTS ALONG WITH MLCAPE OF 2000-3000 J/KG ARE FORECAST INTO
THE EVENING HOURS IN EAST CENTRAL KANSAS. STORM RELATIVE HELICITY IN
THE SURFACE TO 1 KM AS WELL AS EFFECTIVE HELICITY VALUES ARE
EXPECTED TO BE IN THE 150-200 M2/S2 SO ANY STORMS THAT CAN GET GOING
AND BECOME SURFACED BASED WILL HAVE THE POTENTIAL TO PRODUCE A
TORNADO. STORMS THAT DO DEVELOP WILL MOVE SOUTHEAST INTO WESTERN
MISSOURI. THE REST OF THE AREA WILL BE IN SUBSIDENCE BEHIND THE MID
LEVEL TROUGH AND WILL REMAIN DRY THROUGH THE NIGHT. AREAS IN THE
EAST NEAR THE MISSOURI BORDER WILL RETAIN LOW CHANCES OF SHOWERS AND
THUNDERSTORMS THROUGH THE EVENING HOURS. LOWS TONIGHT WILL COOL INTO
THE MID 60S TO LOWER 70S.

THURSDAY WILL SEE ANOTHER SHORTWAVE DROP SOUTHEAST THROUGH THE
NORTHERN AND CENTRAL PLAINS. LOOKS LIKE PRECIPITATION CHANCES WILL
INCREASE THROUGH THE MORNING HOURS AS THE TROUGH MOVES SOUTHEAST IN
THE NORTHWEST FLOW ALOFT. THE SURFACE FRONT WILL REMAIN SOUTH ACROSS
SOUTHERN KANSAS ON THURSDAY WITH A NORTHERLY WIND. EXPECT HIGHS TO
RANGE FROM THE UPPER 70S IN THE NORTHEAST TO THE MID 80S NEAR
CENTRAL KANSAS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 255 PM CDT WED JUL 1 2015

NORTHWEST FLOW ALOFT PREVAILS AT THE START OF THE LONG TERM WITH
THE UPPER RIDGE CENTERED OVER FAR WESTERN CONUS. THE SHORTWAVE
WHICH WAS OVER MT AT 18Z TODAY IS FORECAST TO BE OVER THE CENTRAL
MISSOURI VALLEY BY 00Z FRIDAY. THERE IS ENOUGH SUPPORT TO CONTINUE
A SMALL POP THURSDAY NIGHT...THE MORE WIDESPREAD THUNDERSTORM
ACTIVITY SHOULD BE TO THE SOUTH CLOSURE TO THE STALLED SURFACE
BOUNDARY.

FOR THE WEEKEND...THE 12Z GFS/ECMWF BOTH SWING A SIGNIFICANT
UPPER TROUGH INTO THE NORTHERN TIER STATES BY SUNDAY. IN
RESPONSE...SURFACE PRESSURE FALLS ON THE LEE SIDE OF THE ROCKIES
SHOULD INCREASE THE PRESSURE GRADIENT ACROSS THE PLAINS. THE
INITIALLY WEAK SURFACE FLOW OVER NORTHEAST KANSAS ON FRIDAY IS
REPLACED BY GOOD SOUTHERLY FLOW BY SUNDAY.

THERE WILL BE ENOUGH MOISTURE AROUND AND INSTABILITY TO SUPPORT
SMALL PRECIPITATION CHANCES FRIDAY AND SATURDAY BUT SIGNIFICANT
PRECIPITATION IS NOT EXPECTED. BELOW NORMAL TEMPERATURES ON FRIDAY
SHOULD BE REPLACED BY WARMER TEMPERATURES BY SUNDAY DUE TO WARM
ADVECTION. OVERALL...THE HOLIDAY WEEKEND WILL LIKELY BE MAINLY DRY
OVER NORTHEAST KANSAS WITH SOME SMALL POPS.

FOR THE EXTENDED...AN UNSEASONABLY STRONG COLD FRONT IS FORECAST
TO MOVE THROUGH THE CENTRAL PLAINS EARLY NEXT WEEK. THE FRONT IS
IN RESPONSE TO THE ABOVE MENTIONED UPPER TROUGH MOVING THROUGH THE
NORTHERN CONUS. THERE IS A QUESTION ABOUT HOW FAR SOUTH THE FRONT
WILL GO THIS TIME OF YEAR AS IT MOVES CLOSER TO THE UPPER RIDGE
OVER THE SOUTH. THE UPPER RIDGE SHOULD BE SURPRISED WELL SOUTH OF
NORTHEAST KANSAS ALLOWING THE BOUNDARY TO PUSH THROUGH SOMETIME
MONDAY OR TUESDAY. THE FRONT SHOULD INTERACT WITH A MOIST AND
UNSTABLE AIRMASS OVER KANSAS RESULTING IN A GOOD CHANCE OF SHOWERS
AND THUNDERSTORMS. TEMPERATURES SHOULD BE BELOW NORMAL IN THE
EXTENDED DUE TO RAIN CHANCES..CLOUDINESS AND THE COOL AIR NORTH OF
THE BOUNDARY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 644 PM CDT WED JUL 1 2015

VFR PREVAILS FOR THE NEXT FEW HOURS. WEAK SURFACE LOW MIGRATES
SOUTH AROUND 04Z WITH CONSISTENT SIGNALS FROM SHORT TERM GUIDANCE
ON MOISTURE ADVECTION INCREASING BELOW 2 KFT. MVFR STRATUS IS
EXPECTED TO DEVELOP AT THIS TIME FOR KTOP/KFOE AND 06Z FOR KMHK.
CONDITIONS ARE LIKELY TO LOWER TO IFR NEAR SUNRISE AT KTOP/KFOE
WITH A SLOW IMPROVEMENT TO VFR BY LATE AFTERNOON. A COMPLEX OF
TSRA IS EXPECTED TO TRACK AND WEAKEN INTO NORTHEAST KS THURSDAY
AFTERNOON. COVERAGE AND TIMING UNCERTAINTIES LEAD TO ADDING A
VCTS MENTION FOR NOW.

&&

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

$$

SHORT TERM...53
LONG TERM...JONHSON
AVIATION...BOWEN



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