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Area forecast discussion 
National Weather Service Tulsa OK
1127 PM CST Sat Dec 20 2014

concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm/krog.
Widespread low clouds and patchy drizzle will result in further
deteriorating conditions overnight with all areas transitioning to
IFR/LIFR. Generally overcast conditions will prevail through the
forecast period though visibility should improve after 18z with at
least some improvement in ceilings as well...most areas mvvfr
after 18z.


Previous discussion... /issued 906 PM CST Sat Dec 20 2014/


Patchy drizzle was added to the evening forecast...see discussion below.


A few holes in the stratus deck developed during the day...but the
clouds have filled back in at almost all locations /Copan will
cloud up soon/ as of 03z. Clouds will hang on through the
night...continuing a string of cloudy days and nights that
stretches back to the 17th. As such...lows will not be much
different from today's highs and the forecast is within reason of
the latest hrrr guidance. In addition...weak warm advection in the
low levels is providing just enough lift for patchy
drizzle...which shows up on radar and in some of the metar observation.
Therefore...have added patchy drizzle through the night to the grids. No
other changes are planned to the forecast this evening.


Previous discussion... /issued 525 PM CST Sat Dec 20 2014/

concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm/krog.
Widespread low clouds will persist through the entire forecast
period. MVFR conditions early this evening will transition to IFR
as ceilings lower and visibility eventually becomes reduced
overnight...some areas likely to see a period of LIFR ceilings as
well 12-18z. Modest improvement after 18z Sunday.

Previous discussion... /issued 348 PM CST Sat Dec 20 2014/

another cloudy day for tsa County Warning Area. Clouds likely anchored
for another couple of days before sun arrives on 24th.
Maximum / min temperature adjustments made for mainly cloudy sky.

H500 wave from western Canada will drop into northern
& Central Plains over the next couple of days as West
Coast h500 ridge amplifies. Elongated trough - central
Canada to Texas by Tuesday. This evolution will bring
chance precipitation Monday through Tuesday. European model (ecmwf) WRF GFS &
differ some with this system. Of particular concern is
how fast cold air will arrive in eastern OK northwest
Arkansas Tuesday. If the cold air arrives early the tail end
of precipitation late Tuesday/Tuesday night would be a
wintry mix. Given that the best chance for precipitation will
be Tuesday with high temperatures in low/middle 40s did not put
possible wintry mix in until Tuesday night. And...then
just slight chance extreme eastern OK and northwest Arkansas.

Ridge moves across the region Christmas day while next
upper wave dives from Pacific northwest to The Rockies.
Christmas day promises to offer lots of sun with high
temperatures above normal in the 50 to 60 degree range.

Cold front will sweep through Christmas night / Friday
leaving below average temperatures next weekend. Gw


Tsa watches/warnings/advisories...


Short term...99
long term....99

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