Area Forecast Discussion
Issued by NWS Oklahoma City, OK
FXUS64 KOUN 221802
Area Forecast Discussion
National Weather Service Norman OK
102 PM CDT MON AUG 22 2016
.AVIATION.../For the 18z TAFs/
Latest ASOS/AWOS and satellite observations show moisture
advecting northward on south/southeast winds early this afternoon.
The fog that impacted terminals in the southeast portion of the
area this morning has diminished but stratus/cu have began to fill
in as moisture continues to move northward. Ceilings are in VFR
range at all locations except SPS but with continued
warming/mixing this afternoon bases should lift into the VFR
range. Only two notable changes were made for this issuance. 1.)
a more pessimistic cloud forecast for a few sites through
afternoon based on trends, but ceilings should be VFR so little
impact is expected. 2.) addition of low probabilities of
thunderstorms and/or rain showers in all but far northwest and
northern terminals later tonight and especially by morning.
Stratus should lower and IFR conditions will result for several
sites tonight. Adjustments may need to be made to the timing of
IFR ceiling onset. We will refine the shower/thunderstorm timing
as we develop a better handle on how this will evolve through the
evening and into early tonight.
.PREV DISCUSSION... /issued 335 AM CDT MON AUG 22 2016/
The main concerns are determining rain chances and locally heavy
rainfall potential over the next several days.
This morning, some fog will likely form as low level moisture
quickly increases across parts of southern Oklahoma and western
north Texas. Thus, added patchy fog mention before 10 am
southeast of a Knox City TX to Wichita Falls to Oklahoma City to
Chandler line where visibilities of 3 miles or less are most
likely. Some of this fog could be locally dense with visibilities
less than 1/2 mile, but confidence is low. Kept low rain chances
(20-40%) mainly after 9 am south of a Quanah TX to Duncan to
Holdenville line where some showers and thunderstorms may form as
moisture and potential instability increase in these areas.
This afternoon, isolated to numerous showers and thunderstorms
are expected across southern Oklahoma and north Texas with the
latest models keeping the deepest moisture farther south than
previously forecast, south of I-40. Kept the highest chances near
Atoka and Durant (50-70%) where latest models have a rather strong
depiction of rain in these locations. Locally heavy rainfall will
be the main concern with showers and storms as precipitable water
values increase into the 1.5-2.1" range south of an Altus to
Lawton to Holdenville line. Severe potential appears to be low due
to weak shear and DCAPE values generally just below 1000 J/kg.
Model guidance highs today appeared to be reasonable and were
Tonight into Tuesday, deeper moisture will continue to advance
northward and allow for isolated to scattered showers and storms.
Locally heavy rainfall will once again be the main hazard.
Widespread rainfall and severe storms seem unlikely due to weak
0-6 km shear. Current forecast highs on Tuesday could bust and be
too warm in some locations if clouds and rain hang on across the
area. Breezy conditions may form Tuesday afternoon.
Tuesday night into Wednesday morning, a lull in rain chances may
occur due to some mid/upper level ridging. Kept low rain chances
mainly in northwestern Oklahoma where locally heavy rainfall may
once again occur. Muggy conditions are expected with surface
dewpoints mainly in the upper 60s and lower 70s.
Wednesday afternoon and night, rain chances may increase across
the area, especially in northwestern Oklahoma closer to an
approaching front. Heavy rainfall will remain a concern as well
as strong to severe thunderstorms as 0-6 km shear increases which
would support mainly multicells with damaging winds as the main
hazard. Hotter surface temperatures and breezy conditions are
forecast Wednesday afternoon.
Thursday through Sunday, kept low rain chances in the forecast
nearly each day, though doubt widespread rainfall will occur. A
few storms may be strong with locally heavy rainfall. Surface
temperatures are forecast to be near or slightly below average
during this time frame with higher surface humidity than average.
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 88 71 88 73 / 10 40 50 20
Hobart OK 88 71 88 72 / 10 30 50 30
Wichita Falls TX 87 72 90 72 / 20 50 30 20
Gage OK 90 69 90 72 / 0 20 20 20
Ponca City OK 88 72 89 73 / 0 30 50 20
Durant OK 85 72 90 72 / 70 50 20 20