Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 162332
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
632 PM CDT Tue Sep 16 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Wednesday)
Issued at 317 PM CDT TUE SEP 16 2014

Mostly clear skies across the eastern counties have brought high
temperatures into the lower 70s while far west has been a few
degrees cooler as clouds move in. Dewpoints in the 40s this morning
have risen to the lower 50s for much of eastern Kansas.

For tonight, isentropic lift develops over the eastern half of the
area near the 305K surface. Appears at this time to maximize over
eastern or east Central counties after 06z.  Will start with
slights everywhere but think parcels will need to lift northeast
before isolated storms can form.  Soundings near Emporia and the
Flint Hills refuge carry more CAPE and less mid level capping than
northward locales, reaching around 2000j/kg for a time.  Shear
remains low, however a quickly developing updraft into steep lapse
rates aloft could produce some hail as they develop.  Will focus
some low end chance pops over the east, overnight lows in the 50s.
For Wednesday, surface low over western Kansas slowly develops and
extends surface warm front eastward into the forecast area, and
coupled with the mid level front could provide a focus for another
round of isolated storms. Lifting mechanism is not strong, however,
and may have several hours of subsidence behind morning convection
before chances increase.  Again kept more focus eastward and
generally 35 percent or less all areas.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 317 PM CDT TUE SEP 16 2014

At least some mention of precipitation is in order into Thursday
with warm front in area and veered wind profiles. Could see
convection from Wednesday reinforce the front for more local
development Wednesday evening, but appears better synoptic isentropic
lift and moisture convergence will be in western and central
Nebraska, with upper flow bringing this southeast into a supportive
environment. Shear amounts and elevated lapse rates still not very
strong, but enough moisture for at moderate CAPE and near-severe hail
possibilities. This convection could easily spill over into Thursday
morning, and along with low level moisture pooled northeast of the
warm front (still expected to be to the southwest), temperatures
could be stubborn to rise. Continue to have low confidence in highs
given aforementioned issues, but have most areas a bit cooler than
Wednesday given more low cloud potential. At this point, boundary
layer winds look too strong for any fog concerns but can`t rule out
some around sunrise drizzle for mainly northeastern locations.  By
late Thursday, should see storm focus shift northeast ahead of next
upper wave with upper heights rising locally and will keep Thursday
night dry. Friday still looking like the most likely dry period
through the late week with highs well into the 80s, though still
some potential problems with morning stratus possibilities.

A wet period from Friday night into Saturday evening still quite
possible as the next cold front makes eastward progress through the
Plains. Surface moisture should be high enough for at least
scattered activity, but main wrench continues to be where the
remnants of Odile will be. Latest GFS and ECMWF keep this to the
south, and could potentially be enough subsidence to its north to
keep widespread precip in check here. At this point kept mid-range
PoPs going as just how Odile and the northern states` upper trough
interact is far from certain. Cooler and drier airmass settles in
for early next week under upper ridging.

&&

.AVIATION...(For the 00Z TAFs through 00Z Wednesday Evening)
Issued at 625 PM CDT TUE SEP 16 2014

Mostly clear skies to begin the TAF will likely become overcast
MVFR after 09Z as a warm front approaches but remains just south
of TAF sites. Expect a band of thunderstorms to develop near TAF
sites and drift east after 11Z (high confidence in development,
moderate confidence in location/timing). TOP/FOE stand a better
chance of having TS than MHK. MVFR cigs have a good chance to
lower to IFR conditions with periods of light BR or DZ for a
period from sunrise through 15-18Z or so. Expect cigs to scatter
between 16-20Z with low confidence in exact timing of SCT. May
then have another round of scattered TS develop after 20Z but have
not included at this time due to low confidence in timing/location.

&&

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

$$

SHORT TERM...67
LONG TERM...65
AVIATION...Barjenbruch





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