Flash Flooding and Hail in Kansas, August 15, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
332 AM CDT Thu Aug 15 2013

.SHORT TERM...(Today and Tonight)
Issued at 330 AM CDT THU AUG 15 2013

Three convective complexes, or remnants thereof, were moving across
Nebraska and Kansas early on Thursday morning. The first over
eastern Nebraska has diminished to a broad area of showers with some
weak embedded convection. While the bulk of the precip with this
system will remain north of the forecast area, there has been and
should continue to be development along the southern flank as a
branch of a 30 kt low level jet was veering and converging over
southern Nebraska. Expect a few showers and perhaps a thunderstorm
to move into northern Kansas by sunrise, and some of this activity
could slowly spread south through the morning, with isolated to
scattered coverage expected. The second complex was a weakening area
of storms over southwest Kansas, and is expected to remain west of
the local forecast area.

The third area of storms was located over northwest Nebraska and was
moving southeast. This activity seems to be tied more closely to a
fairly strong short wave trough moving out of northeast Wyoming.
While it is uncertain if these storms will persist, it seems quite
likely that they provide a good track for an area of lift that will
move into north central Kansas by this afternoon. The HRRR, RAP,
NMM, and ARW models, along with some of the broader resolution
models, all paint a picture of thunderstorm development in north
central Kansas by 1 to 5 PM. These same models suggest a weakly to
moderately unstable environment with weaker instability to the east,
and deep layer shear of 30 to 40 kts. If this is indeed the case,
would expect incoming storms to intensify or new storms to develop
with some potential to become strong over north central Kansas. In
areas that do achieve decent instability, hail and downburst winds
would seem to be the greatest threats with any strong storms, but the
tornado threat would be non-zero if supercell storms are able to
develop as LCL's will be low and low level shear adequate. At this
time, unsure if any supercell structures will be realized. Any
severe weather potential seems to be limited to areas near and west
of Highway 81, but perhaps stretching as far east as Highway 77.

Thunderstorm activity should continue to move southeast through the
evening and overnight. The entire area has at least a chance for
storms, but the best chances will be over western and southwestern
parts of the forecast area.

In the absence of showers and thunderstorms, today will be another
pleasant day with a south breeze and high temperatures in the upper
70s to lower 80s. Cloud cover will hold overnight lows in the lower
60s.

Barjenbruch

.LONG TERM...(Friday through Wednesday)
Issued at 330 AM CDT THU AUG 15 2013

Main upper trof exits to the southeast by Friday afternoon.
Continued to mention a slight chance of pops on Friday morning  as
model guidance keeps the low level moisture in place with perhaps a
few lingering isolated showers. Some weak isentropic lift over far
southeast Nebraska may also maintain shower activity across far
northeast Kansas. Most locations however should remain dry Friday with
cloud cover diminishing by late afternoon topping highs around 80
degrees.

Maintained a dry forecast from Friday evening through the weekend as
upper ridge builds eastward into the northern and central plains.
A surface trough developing over eastern Colorado will help to
induce a warming trend beginning Sunday with highs increasing to the
mid 80s for highs. On Tuesday and Wednesday afternoon, high
temperatures are expected to climb back towards normal values near
90 degrees. A slightly tighter pressure gradient over western
Kansas should increase winds during the peak afternoon hours
between 10 and 20 mph. The 00Z GFS remains the outlier by bringing
a quick moving shortwave trof skirting the edge of the ridge Monday
evening. The 00Z ECMWF is consistent in keeping the ridge centered
overhead with a dry forecast. Will continue to monitor trends but
for now kept low category pops over north central areas.

&&

.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1132 PM CDT WED AUG 14 2013

Upper level disturbance over Nebraska will move southeast tonight.
However, shower and thunderstorm activity over eastern Nebraska
has been weakening and is not expected to make it to TAF sites
Thursday morning. A better chance of thunderstorm activity would
occur Thursday evening, especially for KMHK. Would expect VFR
conditions except if a heavy shower or thunderstorm affects TAF
site.

&&

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

SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...60

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
330 PM CDT WED AUG 14 2013

KSZ008>012-020>024-026-034>040-054>056-058-059-152030-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
330 PM CDT WED AUG 14 2013

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS NORTH CENTRAL KANSAS
THIS EVENING WITH INCREASING CHANCES OVERNIGHT. STORMS ARE
EXPECTED TO SPREAD EAST ACROSS NORTHEAST AND EAST CENTRAL KANSAS
LATER TONIGHT. SEVERE WEATHER IS NOT EXPECTED.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THUNDERSTORM CHANCES RETURN FOR THURSDAY AND FRIDAY ACROSS
NORTHEAST...NORTH CENTRAL AND EAST CENTRAL KANSAS. BEST CHANCES
FOR THUNDERSTORMS RESIDE PRIMARILY NORTH AND WEST OF THE KANSAS
TURNPIKE.

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS FOR THE OUTLOOK AREA
MONDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.