Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 262322
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
622 PM CDT TUE JUL 26 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Wednesday)
Issued at 304 PM CDT TUE JUL 26 2016

A ridge of surface high pressure extended across the forecast area
and into Iowa this afternoon with widespread sunshine outside of
broken cloud cover in east central KS. Temperatures have warmed into
the middle to upper 80s while dewpoints hold in the middle 60s to
around 70. Farther aloft, water vapor imagery indicated an organized
short wave trough moving across the Dakotas with an associated
cluster of thunderstorms. An axis of mid level moisture also
extended across eastern OK and southeast MO with a band of
convective activity in that area as well. A few convective showers
have extended into southeast KS, but have been thus far unable to
move into the local forecast area as anything more than cloud cover.

Additional thunderstorm complexes are likely to form in eastern
Colorado and north central Nebraska this evening and while they will
progress toward northeast KS, the local airmass will not be
conducive to continued development and the storms should dissipate
well before reaching the local forecast area. May want to watch east
central KS as a zone for weak isentropic ascent and it could support
a few showers up toward I-35. However, at this time have maintained
a dry forecast as the forcing is quite weak.

On Wednesday, a cold front will approach the KS/NE border region by
late afternoon along with upper level support. Currently, it appears
that the better chances for thunderstorms along the front will be
during the evening hours with a cap in place during the late
afternoon. Have still brought a 30 percent chance into Republic
county by late afternoon on the chance that convergence along the
front is strong enough to overcome the cap. Moderate instability and
modest shear may support some briefly strong storms but the overall
severe threat is quite low through the afternoon...assuming any
storms even develop before 7 PM.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 304 PM CDT TUE JUL 26 2016

Tomorrow night a weak shortwave trough will track over the northern
plains, which will cause an inverted surface trough to form in the
region. During the late afternoon this surface trough should be
located across southeast NE, and will be the focus for convection to
develop. These storms could congeal into an MCS that moves southward
overnight. A few of the models appear to backbuild storms across
western KS while the MCS tracks through central KS. Isolated to
scattered showers and storms will also be possible across eastern KS
out ahead of the MCS as the shortwave tracks over IA. Isentropic
lift in the warm advection could be enough for this activity. The
shear and instability appear to be marginal, and the low level jet
is not well defined or particularly strong. Therefore this MCS could
produce some strong to severe wind gusts although widespread severe
weather is not expected. Some of this activity may linger into the
late morning. Chances continue in the afternoon as the inverted
surface trough becomes a possible focus for redevelopment. Of
course, the environment would have to recover from the morning
activity. The better chances appear to be in far eastern KS.

Thursday night the northwest flow pattern aloft supports upslope
flow across the high plains. During the evening a shortwave trough
tracks over eastern WY and CO. It should be responsible for one or
more MCSs to track across western and central KS. As of now most
of the models keep a majority of the precip south of the forecast
area. Although the NAM moves an area of heavy rainfall across the
eastern KS. Beyond that the northwest flow aloft remains in place
through the weekend as several potential waves track over the
plains. Rain chances therefore will continue through early next
week. This is when the upper ridge builds back over the area allow
warm and drier conditions take hold.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 622 PM CDT TUE JUL 26 2016

VFR conditions are expected through the period.  Winds will remain
light overnight, and shift from the SSE by 18Z.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Sanders
AVIATION...Heller


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