Area Forecast Discussion
Issued by NWS Oklahoma City, OK

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KOUN 230249
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
949 PM CDT Tue Aug 22 2017

.UPDATE...
Adjusted rain chances for the rest of tonight, mainly to lower/
remove them in northern Oklahoma and to increase them in parts of
central and southern Oklahoma as well as western north Texas.

&&

.DISCUSSION...
Heavy rain and flash flooding remain possible tonight, mainly
southeast of a Seymour, Texas to Wichita Falls to Lawton to El
Reno to Edmond to Chandler line.

As of 945 pm, a band of showers and thunderstorms with heavy rain
extended from near Chickasha to Purcell to Coalgate. This band was
slightly weakening as it was moving south. Additional storms were
forming near Lawton to Henrietta, Texas.

Overall, think storms will slowly weaken through the night as they
move south due to the loss of daytime heating. Very heavy rainfall
rates of 2-4" remain possible south of the line mentioned in the
first sentence of this discussion section, which could lead to
localized flash flooding, mainly now through 3 am tonight.

Severe storms are no longer expected tonight due to the loss of
daytime heating and as instability decreases.

The heaviest rainfall has ended tonight across the Oklahoma City,
Norman, El Reno, and Clinton areas as well as much of far western
and northern Oklahoma.

Some patchy fog may form later tonight into early Wednesday
morning where rain occurred earlier this afternoon and evening.
Did not add mention as not sure clouds will clear enough to allow
for sufficient radiational cooling for fog development.

MBS

&&

.PREV DISCUSSION... /issued 615 PM CDT Tue Aug 22 2017/

AVIATION...
Widespread showers and thunderstorms will impact most sites
overnight. Heaviest activity will create temporary MVFR conditions
this evening. Ceilings may drop into MVFR cat late tonight across
central into southern sections of the area before skies clear by
mid- morning. Northeast winds of 8 to 12kts will remain with a
shift back to the southeast at both GAG/WWR by Wednesday
afternoon.

30

PREV DISCUSSION... /ISSUED 234 PM CDT Tue Aug 22 2017/

DISCUSSION...
Cold front continues to slowly move south this afternoon, and the
afternoon convection has already developed along the front in
southwest Oklahoma and the southeast Texas panhandle. Despite
decent instability, wind shear is very low, so although some
storms may briefly become strong or marginally severe, organized
severe weather is unlikely. The primary issue will be locally
heavy rainfall/flooding with the combination of high precipitable
water and slow movement. The special 17Z OUN sounding recorded a
precipitable water content of 1.65 inches, just under the 90th
percentile for this time of year. Storm chances continue through
tomorrow, mainly close to the frontal zone in the south. Return
moisture leads to some additional storm chances tomorrow night
into Friday, mainly west. Then attention shifts to the tropical
system advertised by the models to move inland on the Texas Gulf
Coast late Friday or Saturday. It still remains a question how far
north the moisture will push through Texas or if we will remain
in a more subsident region, so there is quite a bit of uncertainty
later in this forecast period.

Temperatures will remain below average for this time of the year.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  67  85  62  84 / 100  10  10  10
Hobart OK         68  86  64  86 /  20  30  10  20
Wichita Falls TX  71  87  70  87 /  90  40  20  20
Gage OK           62  86  61  85 /  20  10  10  20
Ponca City OK     60  85  59  84 /  20   0   0   0
Durant OK         71  87  69  85 /  60  40  10  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

$$

17/30



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.