Area Forecast Discussion
Issued by NWS Oklahoma City, OK
FXUS64 KOUN 222347
Area Forecast Discussion
National Weather Service Norman OK
647 PM CDT Wed Mar 22 2017
.AVIATION...23/00Z TAF Issuance...
MVFR ceilings will continue to evolve across portions of central
and eastern Oklahoma this evening. Given the past 24 hours,
guidance appears to be over-doing MVFR and IFR ceilings across the
region overnight through Thursday morning. Therefore, decided not
to be as aggressive, given satellite and obs trends, with IFR,
dropping most locations to MVFR for several hours beginning early
Thursday morning. Strong southerly Winds will be a large factor,
especially in western and northwestern Oklahoma. Sustained winds
of 15 to 25 kts are possible, beginning around dawn and through
the day, with gusts approaching 25 to 30 kts. The strongest winds
will likely occur in northwestern Oklahoma, impacting KGAG/KWWR,
with gusts potentially reaching 35 kts in the afternoon, tomorrow.
.PREV DISCUSSION... /issued 321 PM CDT Wed Mar 22 2017/
Short term concerns include low stratus across the area overnight
and possibly some fog across northwest Oklahoma. Forecast
soundings show potential for deep enough saturation for the
possibility of drizzle across north-central Oklahoma late in the
Southerly flow will strengthen significantly tomorrow with near
advisory level winds possible across western Oklahoma. Fire
weather will become a concern (see Fire Weather section below).
Deep closed low will approach from the west tomorrow and
moisture/instability and forcing will be favorable for convection
to form in the Panhandles late in the day. Thunderstorms will
consolidate and move east entering our area during the evening and
progressing across the area in a weakened state overnight.
Meridional flow will not favor particularly steep lapse rates and
with diabatic cooling overnight, instability should be too weak to
support a sustained severe weather threat. Some increase in
convection may occur as early as late Friday morning within a
low-level theta-e ridge, and especially by afternoon across
eastern Oklahoma. Some redevelopment is possible further west in a
narrow corridor of weak instability that may develop during the
afternoon, and if this happens storms would be confined east of
I-35. Some could be severe, especially if instability is able to
rise to levels higher than model guidance currently indicate.
Otherwise, some showers in wrap around moisture are possible
across northwest Oklahoma. Further south dry/windy conditions will
bring fire weather concerns across southwest Oklahoma and western
north Texas during the afternoon.
The next in a series of shortwave troughs will arrive Sunday and
interact with rapidly returning moisture and a destabilizing
atmosphere. Thunderstorms, some severe, are expected Sunday.
Synoptic scale differences in model guidance limit confidence in a
more significant severe weather episode at this time but given the
degree of shear and potentially instability, trends will need to
carefully be monitored.
GFS and its ensembles are much more closed off than the ECMWF with
the system that will affect the area mid week, so confidence is
low. We were fairly broad brush with precipitation probabilities
Tuesday and Wednesday. This pattern would support thunderstorms
and potentially some severe weather.
Elevated to near critical fire weather conditions are expected
across much of the area tomorrow afternoon, with the greatest
potential for initial attack type fire activity across western
Oklahoma and western north Texas where RH values will be lowest.
Forecast soundings show considerable dry layer between 850 and 700
mb that could support lower RH values than currently forecast.
This needs to be monitored as it could increase the fire concern
tomorrow. Near critical to possibly critical fire weather
conditions could develop across western north Texas and possibly
southwest Oklahoma Friday depending on the position of wrap around
moisture and associated higher RH values. Winds will be
sufficiently strong though.
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 57 80 59 74 / 0 0 50 30
Hobart OK 57 81 55 73 / 0 0 50 10
Wichita Falls TX 60 83 59 78 / 0 0 40 30
Gage OK 50 82 52 67 / 10 10 70 30
Ponca City OK 53 79 60 75 / 20 20 40 50
Durant OK 59 79 61 73 / 10 0 20 70