Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 161637

Area Forecast Discussion
National Weather Service Norman OK
1037 AM CST Thu Nov 16 2017

Updated hourly temperature, dew point, and wind forecast through


Low-level moisture advection and isentropic ascent has led to
a northward expansion of stratus this morning. Dew points have
increased by ~5-15F in the last 3 hours because of the moisture
advection. Broken to overcast stratus will persist across parts of
central and southern Oklahoma and adjacent parts of north Texas

Opted to lower high temperatures slightly for most locations
within the stratus deck based on current observations/short-term
models and the anticipation of limited insolation. A few showers
may also occur across southeast Oklahoma within deeper low-level
moisture/isentropic ascent.



.PREV DISCUSSION... /issued 545 AM CST Thu Nov 16 2017/

16/12Z TAFs. Mainly VFR conditions through 18Z before continued
moisture transport with veering winds to southerly is forecast to
allow cigs to drop into the MVFR range. MVFR and IFR conditions
expected after 00Z as higher quality moisture spreads northward.
Areas of fog and drizzle will be possible toward and after 06Z
taking some terminals into IFR/LIFR conditions, mainly from KSPS
up through KLAW/KOKC. This will be monitored for timing and
confidence increase for later inclusion in forecast.

PREV DISCUSSION... /issued 337 AM CST Thu Nov 16 2017/

Post-frontal northerly flow lessened overnight and radiative
cooling north of cirrus across northern Oklahoma has resulted in
some sub-freezing temperatures. A few locations close to the
Kansas border will be in the upper 20s early this morning. Winds
are expected to become southerly later this morning and low level
moisture, along with stratus, will surge northward again today.
Later tonight low-level saturation may be deep enough for some
drizzle or shallow convective showers beneath the pronounced EML
across the eastern counties. If low level confluence and moisture
axis shifts westward then a period of drizzle would be possible in
OKC area late tonight through early tomorrow. We`ll monitor trends
and make adjustments as needed. Also, some fog seems possible,
with the best chance of low visibilities on the western edge of
stratus where moisture return is shallow. This would be across
mainly central and western Oklahoma.

Model guidance has come more into agreement with timing of a
fairly significant trough and associated cold front that will
affect the area Friday. Anomalous warmth is likely, particularly
across the western portion of the area but the west to east
temperature gradient is difficult to forecast at this time range
given the potential for lingering stratus across the east. For
now, we tightened the gradient keeping warmest temperatures in the
southwest where cirrus is less likely to be an impact. Still very
warm in the northwest but a bit below the higher end of guidance,
and cooler than most guidance for the southeast given the
likelihood of persistent stratus for much of the day. Gusts to
around 35 mph are possible where we mix the deepest given strong
momentum aloft.

The cold front will move through during the evening and clear the
area overnight. Post-frontal winds will be quite strong on
Saturday, likely around 25 mph sustained with gusts potentially
approaching 40. Near to slightly below average temperatures will
be seen for the weekend.

Run to run consistency in medium range guidance for early/middle
of next week is poor, and no discernible trend was seen, except
for perhaps deeper more amplified Great Lakes troughing. The
pattern will be more amplified and a low probability precipitation
event is possible in the late Tuesday through Wednesday time
frame, but deep moisture return isn`t expected and timing of
ascent is unknown at this point. We removed precipitation chances
for now.


After collaboration with surrounding offices we decided to hold
off on a Fire Weather Watch that would`ve included portions of
northwest Oklahoma. Despite a favorable synoptic pattern, there is
a fairly significant signal for cirrus across the area that
would`ve had the best chance of deep mixing and RH/wind
thresholds being exceeded. Recent RH recovery overnight has led
to near or slightly below normal ERC values. Some recovery is
expected today with relatively warm/breezy conditions, but there
is an increasing signal for shallow moisture return and
potentially fog/dew late tonight and this may continue to limit
fuels somewhat. An active fire day is still quite possible with
initial attack type activity across western Oklahoma and possibly
western north Texas.



Oklahoma City OK  61  56  76  51 /   0  10  10   0
Hobart OK         64  53  81  50 /   0   0   0   0
Wichita Falls TX  67  58  84  55 /  10   0   0   0
Gage OK           65  51  82  45 /   0   0   0   0
Ponca City OK     61  54  75  48 /   0  20  20   0
Durant OK         62  60  73  59 /  20  20  20  10




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