Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 192327 AAA

Area Forecast Discussion...UPDATED
National Weather Service Norman OK
627 PM CDT Tue Sep 19 2017

20/00Z TAFs. VFR conditions expected to prevail across the region
with gusty south winds ahead of approaching cold front. MVFR
restrictions will be included at KSPS for the first couple of
hours due to shra/tsra near that terminal. Cold front will move
over northwest and west-central Oklahoma terminals near or shortly
after 12Z with the front forecast to stall before passing over
rest of terminals. Scattered TSRA cannot be ruled out near front
late tomorrow but will not include in this forecast.


.PREV DISCUSSION... /issued 248 PM CDT Tue Sep 19 2017/

Near term focus is on convective potential across far southwest
Oklahoma and western north Texas. Latest visible satellite shows
some enhancement in the vicinity of Wichita Falls over the last
hour, and some more substantial echos within the last few minutes.
Although deep layer shear is fairly weak for organized storms,
strong diabatic heating and a moist boundary layer with fairly
steep mid level lapse rates are contributing to at least moderate
instability. With such a well mixed boundary layer, isolated at
least brief strong to severe wind gusts will be the primary

Convection should wane later this evening but it`s not out of the
question that isolated redevelopment may occur later tonight
across south-central Oklahoma as warm advection strengthens.

Convergence along a weak surface boundary tomorrow could be
sufficient for isolated thunderstorm development late in the day
as we destabilize once again. However the capping inversion
appears more substantial than today, owing to subsidence/mid-level
height rises seen in the models. This should limit convective
development. We`ve confined probabilities to the far northeast and
to the south-central portion of the area. SREF members all have
varying degrees of CIN, but the general consensus is less CIN and
a better chance of convective initiation over south-central
Oklahoma. This may need to be refined in the overnight forecast.

Thursday holds some potential for isolated convective development
in western Oklahoma given a subtle shortwave trough and continued
moist unstable air mass. We`ll re-evaluate this further tonight
and tomorrow and may need to re-introduce low probabilities then.

Above normal temperatures will continue until deep western trough
approaches and clouds/rain chances increase. Sunday through Monday
look like potentially the wettest periods as one shortwave trough
rotates around deeper closed low. Medium range guidance varies
somewhat on character of longwave early next week so it is unclear
at the moment how long the more significant rain chances may

Fire weather is another concern over the next few days,
particularly this afternoon, Thursday and Friday afternoons, as RH
falls across western Oklahoma coinciding with enhanced southerly



Oklahoma City OK  74  93  75  91 /  10  10  10   0
Hobart OK         72  96  73  96 /  20  10  10  10
Wichita Falls TX  74  98  76  95 /  30  10  20  10
Gage OK           66  88  65  96 /   0   0  10  10
Ponca City OK     76  94  75  94 /  10  10  20   0
Durant OK         74  94  75  93 /  10   0  10  10




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