Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 181134
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
534 AM CST Tue Dec 18 2018

...Updated Aviation Discussion...

&&

.AVIATION...
For the 12z TAFs:

Some stratus and fog is possible this morning across central and
southern Oklahoma and western north Texas. Otherwise 12,000 -
25,000 ft ceilings may at least temporarily be seen through the
end of the TAF period. Toward the end of the TAF period there is a
low probability of MVFR or IFR stratus across southern/central
Oklahoma and north Texas again.

A few notes for ongoing stratus/fog situation:

For OKC: IFR stratus may build in shortly. Will Rogers will be on
the northern end of more extensive stratus so we kept it TEMPO for
now.

For OUN: IFR stratus should persist into mid-morning. Current T/Td
spread doesn`t support significant visibility reductions.

For SPS: Thicker cirrus moving in should preclude a substantial
drop in visibility from current observations and ~2-3 mile
visibilities should occur through mid morning.

For LAW: Latest METAR shows 7sm and with thicker cirrus moving in,
a significant reduction seems unlikely. Through mid-morning we
have a TEMPO for MVFR visibilities.


&&

.PREV DISCUSSION... /issued 431 AM CST Tue Dec 18 2018/

DISCUSSION...

Currently a Dense Fog Advisory is in effect for portions of
southeast and south-central Oklahoma through 9:00 AM. Visibilities
in the Durant area have fallen to a quarter of a mile, while
visibilities are around 1 3/4 miles in Atoka. Across the area,
there are light southeast winds that are advecting higher moisture
values that are in the mid to upper 40s. There is some concern
for how far north and west this fog will form, currently the
moisture axis extends from Waurika east to Sulfur and over to Ada
and Stuart. This will be closely monitored to see if the Dense Fog
Advisory will need to be expanded. After sunrise and temperatures
begin increasing, the fog isn`t expected to persist much longer.

For late Tuesday afternoon through Wednesday morning, a low pressure
cyclone moves into the area and will bring a chance of
precipitation. This cyclone and associated trough will produce
primarily a light rain, with higher chances of precipitation in
southern and eastern Oklahoma. There is a chance for some
instability to be present with this system Wednesday afternoon and
evening, so some thunder and an isolated thunderstorm may occur with
the rainfall. No severe weather is expected with this system.

Another low cyclone will move through the area late Wednesday into
Thursday. The second cyclone will deepen as it exits the area, which
will tighten the surface pressure gradient and also produce gusty
northwest winds for Thursday. Lower relative humidites due to a
drier airmass and high winds will bring a concern for fire
conditions to the area, particularly in western Oklahoma where there
has been less recent precipitation.

After Thursday, the next chance of precipitation appears to be at
some point mid next week. There`s quite a bit of uncertainty in the
models on when this will occur, however it is consistent that the
low pressure and trough that will be moving through the forecast
area will produce precipitation. The current forecast reflects the
faster of the solutions: precipitation chances starting on next
Monday (Christmas Eve) in southeast Oklahoma, and transition to a
chance of precipitation across the entire forecast area next Tuesday
(Christmas Day).

Zwink

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  59  42  58  40 /   0   0  20  20
Hobart OK         58  38  62  39 /   0   0   0   0
Wichita Falls TX  62  44  62  43 /   0  20  20  10
Gage OK           59  32  61  34 /   0   0   0   0
Ponca City OK     58  38  58  38 /  10   0  20  20
Durant OK         61  44  59  43 /   0  20  40  50

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Dense Fog Advisory until 9 AM CST this morning for OKZ041>043-
     046>048-050>052.

TX...None.
&&

$$

12/50/12


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