Severe Thunderstorm Warning 120, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
635 PM CDT Sat Aug 9 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Sunday)
Issued at 313 PM CDT SAT AUG 9 2014

Water vapor imagery at 19Z depicts multiple vorticity maxima
rotating over southern WY, Nebraska, and South Dakota. The southern
WY wave is expected dig southeast towards the central plains later this
afternoon into the evening. At the surface lee trough continues
to deepen over eastern CO as the upper wave approaches, progged to
develop thunderstorms across western KS and NE during the early
evening. Closer to northeast KS, cloud cover continues to clear
eastward, quickly rising temperatures in the 80s and some lower
90s with dewpoints hovering near 70 degrees. Sfc CAPE is near 2500
J/KG and effective shear around 30 kts across north central areas
where a residual outflow boundary is located. There is some
indication from short term guidance of perhaps scattered storms
forming near this OFB across portions of north central KS during
the late afternoon/early evening. If they are able to form, storms
initially would be strong or severe with damaging winds and large
hail possible.

Focus for more widespread precip turns to this evening with an MCS
developing over southern NE, quickly tracking southeast across
northern and central KS overnight. While models vary on the exact
track and placement of higher QPF, consensus track of the trough
axis and placement of enhanced QG frontogenesis show western areas of
the CWA seeing the better chances for locally heavy rainfall. In
addition, damaging winds are the main hazards with the MCS.
Another perturbation in the main wave quickly follows, developing
additional showers and thunderstorms across much of the CWA early
Sunday morning through afternoon as the wave slowly progresses
southeast. A weak cold front shifts winds towards the north during
the day, progged to be near the I 35 corridor by late afternoon.
Additional strong storms may intensify or develop near the
boundary. If so, strong winds and hail would be the primary
hazards. Rainfall and cloud cover lowers highs on Sunday down to
the lower and middle 80s.

.LONG TERM...(Sunday Night through Saturday)
Issued at 313 PM CDT SAT AUG 9 2014

Northwest flow reestablishes itself
over the forecast area and drives surface high pressure southward
out of the Northern Plains.  May have some lingering departing
showers and thunderstorms on Sunday night but should clear into
Monday morning to the southeast.  850mb temperatures of 15-18c cool
to generally 14-16C by later Tuesday, leaving highs generally in the
middle 80s Monday with a few degrees cooler on Tuesday.  Lows in the
60s Sunday night may very well drop to lows in the upper 50s Monday
night with cool advection and mostly clear skies. Outside chance of
rain in the far western counties Tuesday afternoon, but at this time
is forecast to remain west of the forecast area.

Strong upper ridging aloft will preclude storm develop Tuesday
evening through at least Wednesday evening. Latest runs of the GFS
and ECMWF are quite different in the track of the next system. ECMWF
is much slower in breaking down the ridge while the incoming system
is stronger and more progressive in carrying the shortwave trough
through Wednesday evening and Thursday. Sided closer to the GFS with
precip chances mentioned for the western half of the CWA until the
ECMWF gains better consistency between model runs. Flow becomes
quasi-zonal through Saturday with multiple shortwave troughs
rotating through the central plains. Chances for showers and
thunderstorms will be periodic through Thursday through Saturday.
Temperatures start off below normal in the lower to middle 80s.
Increasing warm advection from the southwest will warm highs to near
90 Friday and Saturday. Overnight lows range from the low 60s
Wednesday and Thursday, to near 70 degrees through Saturday.

&&

.AVIATION...(For the 00Z TAFs through 00Z Sunday Evening)
Issued at 635 PM CDT SAT AUG 9 2014

Boundary southwest of MHK focus for isolated TSRA while a
widespread area of storms was over western Kansas and central and
western Nebraska. These storms should slowly move east southeast
and affect the terminals in the 04Z-06Z period then continue
through the night with the more favored time of 07Z-12Z. MVFR/IFR
vsbys expected with MVFR cigs. Improvement to VFR expected after
17Z.

&&

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

SHORT TERM...Bowen
LONG TERM...67/Bowen
AVIATION...53

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
334 PM CDT SAT AUG 9 2014

KSZ008>012-020>024-026-034>040-054>056-058-059-102045-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
334 PM CDT SAT AUG 9 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH
CENTRAL AND NORTHEAST KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A SLIGHT CHANCE OF ISOLATED SEVERE THUNDERSTORMS
OVER NORTH CENTRAL KANSAS LATE THIS AFTERNOON. IF STORMS DEVELOP
AND MOVE INTO THE AREA, LARGE HAIL AND DAMAGING WINDS ARE
POSSIBLE.

A COMPLEX OF THUNDERSTORMS IS EXPECTED TO MOVE ACROSS THE AREA
THIS EVENING INTO THE OVERNIGHT PERIOD. DAMAGING WIND GUSTS MAY
BE POSSIBLE...PRIMARILY WEST OF A LINE FROM WASHINGTON...TO
JUNCTION CITY AND HERINGTON. THE COMPLEX OF STORMS WILL WEAKEN AS
THEY MOVE ACROSS NORTHEAST AND EAST CENTRAL KANSAS AFTER MIDNIGHT
WITH GUSTY WINDS AND LOCALLY HEAVY RAINFALL POSSIBLE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THUNDERSTORMS WILL LIKELY PERSIST ACROSS MUCH OF THE AREA UNTIL
MIDDAY SUNDAY BEFORE GRADUALLY DIMINISHING WEST TO EAST IN THE
AFTERNOON AND EVENING. LOCALLY HEAVY RAINFALL AND GUSTY WINDS
COULD STILL ACCOMPANY A FEW OF THE THUNDERSTORMS SUNDAY MORNING.

THERE IS A CHANCE FOR MORE THUNDERSTORMS ACROSS THE AREA WEDNESDAY
NIGHT INTO FRIDAY OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED ACROSS NORTH CENTRAL KANSAS LATE
THIS AFTERNOON AND EVENING.