Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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000
FXUS64 KOUN 271744
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1244 PM CDT Thu Jul 27 2017

.AVIATION...
Cold front/prefrontal trough extends from near Erick to
around El Reno/Piedmont to an area of low pressure in
north central Oklahoma. Per KTLX...the boundary is moving
slowly southward, but may become nearly stationary during the
afternoon with hot and veered conditions across the southern
half of Oklahoma and north Texas. RAP soundings suggest just
enough of a cap will remain in place to prevent afternoon
storms along the front. However, dewpoint temperatures are
a little low, so except there is a decent chance of some storms
during the mid to late afternoon. OKC/CSM/HBR will have the best
opportunity for storms with strong outflow winds.

During the evening, models suggest additional precipitation will
develop, especially across the northern half of Oklahoma.

Overall confidence in frontal timing and storms is somewhat low.


&&

.PREV DISCUSSION... /issued 615 AM CDT Thu Jul 27 2017/


AVIATION...

For the 12z TAFs:

Showers will persist through at least mid-morning across roughly
the northern half of Oklahoma. A cold front will move south slowly
across the area today bringing a shift to northerly winds, and
possibly a brief period of MVFR stratus this morning to GAG/WWR.
Destabilization this afternoon will support isolated to scattered
thunderstorm development this afternoon and we have included
PROB30 at all but the southwest TAF sites. Best chance of a storm
will be at GAG/WWR/OKC/OUN from mid-afternoon through mid-evening.

PREV DISCUSSION... /issued 344 AM CDT Thu Jul 27 2017/

DISCUSSION...
Convective showers and isolated thunderstorms are ongoing early this
morning in a band of enhanced mid-level moisture apparent on 7.34
water vapor channel and anomalous short term model PWAT values.
Very weak ascent is noted around 315k surface. Convection should
gradually weaken this morning as flow near 315k surface veers and
weakens.

We have adjusted dew points for today upward given the tendency
for models to be too low over the last day or two. This, along
with hot temperatures south of the front, will contribute to heat
indices that are in the dangerous territory for portions of
central Oklahoma. The ongoing Heat Advisory looks good in both
space and time and was not adjusted.

A surface front is now entering the far northwest corner of Oklahoma
and should progress slowly southeastward today. Convergence along
the front should focus isolated to scattered thunderstorm
development in a moderately unstable environment later this
afternoon, with the greatest coverage probably in a relatively
narrow band generally near and north of I-40. Weak mid-level lapse
rates and meager deep layer shear should limit the potential for
severe thunderstorms. Although modest dry mid-level air atop a hot
well-mixed boundary layer will contribute to min/max theta-e
differences in the vertical of at least 20K and so a few
microburst strong/severe wind events will probably occur.
Convection should peak in intensity and coverage during the late
afternoon through mid-evening.

For the next several days we will be on the eastern periphery of mid-
upper high heights center to our west. Occasional perturbations in
northwesterly flow and/or sustained convection originating in the
Rockies will occasionally impact our area. We have made little
chance to the going forecast and have confined highest precipitation
probabilities during this period to roughly the western half of the
area.

BRB

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  74  93  71  91 /  40  30  10  10
Hobart OK         75  95  73  93 /  40  30  20  20
Wichita Falls TX  76  98  75  95 /  20  20  20  20
Gage OK           70  91  70  90 /  40  30  30  20
Ponca City OK     73  90  67  90 /  30  20  10   0
Durant OK         76  96  73  92 /  20  20  20  20

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 8 PM CDT this evening for OKZ024>032-039>043-
     045>048-050>052.

TX...None.
&&

$$



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