Area Forecast Discussion
Issued by NWS Tulsa, OK
FXUS64 KTSA 261101
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE Tulsa OK
501 AM CST THU NOV 26 2015
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 12Z TAFs, MVFR ceilings will prevail at all sites during
the day today. Conditions will slowly deteriorate this afternoon
and evening as widespread heavy rainfall spreads across the
region. IFR ceilings and visibilities will prevail at all sites
by this evening for the duration of the forecast period.
.PREV DISCUSSION... /ISSUED 214 AM CST THU NOV 26 2015/
The main forecast challenges/concerns continue to be heavy
rainfall/flooding and winter weather potential thru the weekend.
There were no major changes to the forecast rationale from what we
have had advertised for the past day or so. A strong and shallow
cold front will plunge south and east tonight into Friday across
the region...and will interact with unseasonably moist air in
place /PW values more than 3 times climatology for this time of
year/ to produce bands of heavy rain and embedded storms beginning
late this afternoon and gradually spreading south Friday and
Saturday. The flash flood watch in effect tonight and Friday has
been extended through Saturday for southeast OK into western AR.
The heaviest rains will fall mainly along and south of
I-40...where multiple rounds of rainfall are expected going into
the weekend. After all is said and done...between 4 and 8 inches
of rain is expected...which will likely cause river and flash
flooding. Some rivers in southeast OK could reach moderate or even
major flood stage from this event.
With a well established warm layer aloft in place in the SW flow
regime ahead of the large positive tilt upper trough to our
west...all precip will fall as liquid. So the only question from a
winter weather perspective will be where the surface freezing line
sets up. The latest data from the NAM...a model which tends to
handle the shallow cold air better...suggests that the freezing
line will come far enough southeast to allow for some light icing
mainly west of highway 75 in northeast OK Friday night into
Saturday. At this point it still appears that ice accumulation is
not expected in the Tulsa metro. With borderline surface temps and
lighter precip forecast there...it appears the main impact would
be on bridges. Since this would be an advisory level event and
still in the third period and later of the forecast...no winter
weather headlines are planned at this time. That can be addressed
The rain will come to an end Monday as the slow moving western
CONUS trough finally lifts northeast over the Plains.
OK...Flash Flood Watch from this evening through Saturday afternoon
Flash Flood Watch from this evening through Friday afternoon for
AR...Flash Flood Watch from this evening through Saturday afternoon