Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 181107

Area Forecast Discussion
National Weather Service Norman OK
607 AM CDT Sun Mar 18 2018

Please see the 12Z aviation discussion below.


Flight conditions will quickly deteriorate near and after sunrise.
At least MVFR cigs are expected to develop. In addition, showers
and thunderstorms will initially be possible from SW OK and north
TX around 14-18Z, and then the rest of OK from 18-24Z. Some hail
and strong wind gusts will also be possible, although do not feel
confident enough to include a mention right now. The previous may
be most likely at OKC/OUN this afternoon, and PNC late tonight
(after 06Z). A breezy wind shift from the west and then northwest
is expected near the end of the forecast period.


.PREV DISCUSSION... /issued 520 AM CDT Sun Mar 18 2018/

Severe storms remain the number one concern during this forecast
period, with some elevated to near critical fire weather
conditions possible through Mon.

Two features of interest are present in water vapor imagery this
morning. The first is a subtle mid level shortwave trough
currently moving over west TX and SE NM. This wave will approach
our SW zones around 18Z, and should lift over central OK by early
afternoon. A few elevated storms will be possible with this
activity around lunchtime and through the afternoon across
central and northeastern OK as isentropic ascent peaks. Given
very steep mid level lapse rates, and mid 500 mb jet streak, would
not be surprised to see some hail stones meet or exceed severe
limits with this activity. Further south, most hires solutions
continue to suggest a few discrete cells developing near the Red
River near the surface low, along and ahead of the dryline,
within the warm sector. The question is, how far north will the
instability axis reach and will the inversion be too much to
overcome. For now it appears it looks like the most favorable
conditions will hug the river. Regardless, if storms do develop
here expect all severe weather threats. The tornado threat is low,
but given backed surface flow and moderate southwesterlies they
certainly cannot be ruled out. The second feature is a stout,
compact, negatively tilted mid to upper trough entering NW AZ.
This feature will result in rapid height falls around 03-06 across
northern OK. Elevated storms will likely accompany this feature,
with damaging winds and perhaps hail possible with them.

The deep surface low associated with the aforementioned trough
will move into NE OK through the early morning hours Mon. A tight
pressure gradient on its backside will yield breezy north winds
throughout the day. For now, speeds appear they will remain just
below advisory criteria but this will be watched over the next 12
hours for possible headlines. Near critical fire weather
conditions will also be possible with the breezy northwest winds,
especially east of I-35. However, low level post frontal stratus
may keep temps a bit cooler than the consensus so have opted to
lean closer to the NAM. Higher RH should limit the overall fire
threat. The winds will only slowly calm after sunset considering
the lingering pressure gradient.

Things will finally calm down Tue-Wed. South surface flow will
return during the day Wed with lee troughing thanks to an upper
ridge axis and quasi zonal mid to upper flow over the Rockies.
Temps will climb rapidly through late week as the ridge moves over
the central CONUS. Some locations across western north TX may
reach 90 degrees. A mid to upper trough by next weekend appears
likely, which could support additional strong to severe storms for
a portion of our FA.


Oklahoma City OK  60  45  55  38 /  70  10  10  10
Hobart OK         62  46  60  36 /  60   0   0   0
Wichita Falls TX  69  50  67  39 /  50   0   0   0
Gage OK           63  44  50  31 /  30  40  10   0
Ponca City OK     60  46  51  37 /  70  70  20  20
Durant OK         68  51  68  43 /  50  40   0   0




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