Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 240449

1149 PM CDT Wed Jul 23 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Thursday)
Issued at 234 PM CDT WED JUL 23 2014

Observational analysis at 1930Z show two clusters of thunderstorms
originating from weak embedded shortwave troughs within the upper
northwest flow. The first wave brought needed rain to portions of
the area before strengthening into an MCS and pushing southward into
OK at this hour. The second cluster that had produced severe storms
in NE this morning was continuing to weaken southward as it
encounters more stable air across north central KS.

For tonight, surface high pressure slides southward towards east
central KS as light northeast winds veer to the southeast by
morning. Good radiational cooling near the ridge axis drop overnight
lows to the low and middle 60s. Upper ridge centered over the
panhandles edges slightly eastward late tonight creating some
uncertainty on where the next weak shortwave trough will track as it
rounds the eastern edge of the ridge. High resolution, short-term
guidance in addition to the latest few runs of the ECMWF, GEM, and
NAM are slower and further east with the wave compared to the GFS.
Cannot rule out scattered thunderstorms developing over the high
plains, tracking southeast, and clipping portions of northeast KS
Thursday morning. Inserted slight chances through mid morning based
on variability of guidance and subsequent weak nature of the wave.
Severe storms are not expected with a weakly unstable airmass. Sfc
trough slowly deepens over the High Plains during the afternoon
tomorrow increasing southeast winds between 15 and 20 mph sustained
over north central KS. Stronger mixing through the BL and increasing
warm advection from the west will boost temps back to the low 90s
for north central KS. Much of east central and northeast areas stay
slightly cooler in the middle to upper 80s.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 234 PM CDT WED JUL 23 2014

Weak system moving across Northern Plains and Upper Midwest
Thursday night may brush far northeast KS and have slight chance
thunderstorms in that area overnight. Subsidence just northeast of
upper ridge axis and southwest low-level winds should make Friday
another hot day with highs reaching the upper 90s far east with
100 to 105 over central KS. Heat advisory will likely be needed as
dewpoints in the east will be at least 70 with mid 60s over north
central. This combined with the high temperatures should result in
peak afternoon heat index values around 105 or higher.

A greater amount of mid and high clouds on Saturday should keep
temperatures a little cooler, in the mid to upper 90s, but dewpoints
in the upper 60s to around 70 will still result in a sultry day
and heat indices in the upper 90s to 100 to 105. Inverted trough
and surface front move across the area on Saturday. Warm temps
aloft and resultant cap will likely limit convective coverage but
any storms that do form would have the chance for strong winds.

After the front moves out of the area Saturday night, cooler and
drier conditions are in the forecast through Tuesday. Northwest
flow aloft with no discernable shortwaves will result in highs
mostly in the 80s and lows Sunday night and Monday night in the

The next chance of precipitation in this northwest flow would
appear to be Tuesday night and Wednesday, with the best chance in
north central KS. Still, models are not consistent in where
precipitation with this system will be as the ECMWF confines the
rain chances to the western half of the state while the last two
runs of the GFS have a more amplified shortwave trough coming
through and would spread precip chances eastward. This also
corresponds with 12Z GFS Ensemble.  Given uncertainty, just have
slight chance POPs during that time period.


.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1147 PM CDT WED JUL 23 2014

Expect VFR conditions. Any isolated thunderstorms during morning
hours will remain north of the terminals. Winds will become
southeast at 8 to 12 KTS with higher gusts after 14Z and continue
through the afternoon and evening.




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