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fxus64 koun 181550 

Area forecast discussion
National Weather Service Norman OK
950 am CST Wed Jan 18 2017

adjusted rain chances through the afternoon.


observing radar trends from kfws and obs, rainfall has remained
confined to North Texas and is likely to just skirt south central
Oklahoma. Given this trend, have dropped categorical chances for
rain and replaced with chance of sprinkles for south central
Oklahoma. Did the same thing in the northwest, as obs over the
last two hours have reported no rain and light returns on kvnx
suggest not much is reaching the ground.

Temperature forecast remains on track, highs this afternoon are
still expected in the low to mid 50s.



Previous discussion... /issued 553 am CST Wed Jan 18 2017/

the January 18-19, 2017 12 UTC taf discussion follows:

patchy dense fog and low ceilings are impacting southern Oklahoma
and western North Texas this morning (ksps/klaw). Expect flight
conditions at these terminals to improve to MVFR by mid-morning.
Otherwise, a low confidence forecast through today. At the other
terminals, currently expect VFR ceilings through much of the
daytime hours with brief periods of MVFR ceilings possible--
especially across western Oklahoma (kcsm/khbr).

By this evening into the overnight hours, deteriorating flight
conditions are expected at all terminals. Fog/mist, drizzle, and
low ceilings are expected to develop between 03-06z and become
prevailing toward the end of the taf period. Most terminals are
expected to drop to IFR flight conditions; however, LIFR
conditions will be possible. Greatest confidence for at least
temporarily LIFR conditions and drizzle between 09-12z will be
across central Oklahoma from klaw to kokc/koun to kpnc.

Winds will remain light from the south to southeast through the
taf period.


Previous discussion... /issued 336 am CST Wed Jan 18 2017/

showers continue to dissipate this morning with the measurable
precipitation generally confined across western Oklahoma in
association with the vort Max and southeast Oklahoma with
isentropic ascent. Will maintain a chance of showers across the
northwest this morning as the vort Max lifts northward into Kansas.
Across southeast Oklahoma, both convective-allowing models and
the nam12 indicate there will be at least a slight chance of
showers in the southeast through this evening. Progged 295 k
isentropic surfaces indicate some ascent coincident with the quantitative precipitation forecast

For tonight, at least patchy fog will be possible as suggested by
various guidance (sref/rap13/nam12). The possibility of fog seems
reasonable because of the recent rains and for many locations, the
forecast low temperatures are equal to or lower than this
afternoon's dewpoints. In addition, forecast bufr soundings
indicate some drizzle will be possible--espousal near I-35 to the
east. Forecast soundings at kokc/kpnc/kadm all indicate a
relatively deep saturated layer from the sfc to ~925 mb coincident
with weak isentropic ascent at the 290 k insentropic surface.

Thursday will begin a warming trend with temperatures around 10f
above average. Friday will be even warmer as both the 18/00z GFS
and European model (ecmwf) indicate 850 mb temperatures ranging from 9-11c with
south to southwest low-level flow. As a result, high temperatures
are forecast to be in the 60fs and 70fs (~15f above average). Near
critical fire weather conditions will be possible--especially
across western Oklahoma and western North Texas.

Seasonably warm weather will continue into Saturday as the next wave
approaches the Southern Plains. Ascent ahead of wave may result in
some showers across the west Saturday afternoon.

The GFS and European model (ecmwf) are in excellent agreement that a closed mid/upper-
level low will track across the Red River late Saturday into
Sunday morning. Northern Oklahoma will be within the deformation
zone on the north side of the low. Western North Texas may get dry
slotted with minimal precipitation. The GFS has a greater
magnitude of cold air advection than the European model (ecmwf) with 850 mb
temperatures down to -1c in far northwest Oklahoma. Bufr sounding
from kgag still indicate liquid precipitation as temperatures warm
above freezing just below 850 mb. So for now, opted to keep all
precipitation liquid. Very breezy conditions are expected Sunday
afternoon in the system's wake. This may result in near critical
fire weather conditions once again across the west.

For Monday, southwest flow aloft returns ahead of the next wave.
Consequently, seasonable temperatures are expected with a return
to southerly winds by Monday afternoon. The greatest
ascent/precipitation chances from this system is currently progged
to stay north of oklahoma; however, the airmass behind this system
will be colder than the previous system (though not too cold).
Therefore, at least slightly below average temperatures are
currently expected on Wednesday.



Preliminary point temps/pops...
Oklahoma City OK 52 41 61 38 / 10 10 0 0
Hobart OK 52 41 61 37 / 10 0 0 0
Wichita Falls Texas 52 40 67 42 / 10 10 0 0
gage OK 54 40 58 33 / 20 0 0 0
Ponca City OK 53 42 58 39 / 10 10 10 10
Durant OK 50 46 65 45 / 20 20 0 0


Oun watches/warnings/advisories...

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