Area Forecast Discussion
Issued by NWS Tulsa, OK

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FXUS64 KTSA 281142
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
542 AM CST Tue Feb 28 2017

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Widespread MVFR ceilings will be maintained through much of the
morning with a gradual rise especially across NE OK by early
afternoon. Isolated storms were mentioned over NW AR terminals by
late afternoon with a higher chance of storms mentioned late
tonight ahead of the frontal passage. Periodic MVFR conditions
will be maintained prior to the front with VFR expected once the
front passes.

&&

.PREV DISCUSSION... /Issued 302 AM CST Tue Feb 28 2017/

DISCUSSION...
Both severe weather and fire weather concerns will dominate the
next 24 hours of the forecast, with considerably more quiet
weather for much of the remainder of the forecast period.

A few showers/thunderstorms are ongoing early this morning across
far eastern portions of the forecast area in a region of enhanced
warm advection spurred by a modest low level jet. The bulk of this
activity will be east of the forecast area by sunrise, with only
a slight chance of additional showers and thunderstorms across far
eastern Oklahoma and western Arkansas through mid afternoon.

By mid afternoon, forecast soundings across far eastern Oklahoma
and especially, western Arkansas indicate a weakening cap in
response to increased deep layer moisture and warmer surface
temperatures due to a decrease in low level cloud cover. Isolated
to scattered thunderstorms will be possible, with the greatest
likelihood along and east of Interstate 49. With near record
instability levels in place for this time of year and very strong
wind fields, any thunderstorm that develops will likely be
supercellular with very large hail, damaging winds, and tornadoes
all possible. Storms will move very quickly to the east-northeast,
with storm motions 45 to 50 kts. As a result, if storms initiate
as far east as currently expected, the afternoon and early evening
severe threat may only last for a couple of hours in western
Arkansas before transitioning into central Arkansas.

In addition to the afternoon threat in western Arkansas, there is
a small chance that thunderstorms may develop along the dryline
farther west in parts of central Oklahoma, moving into parts of
eastern Oklahoma during the late afternoon and early evening
hours. With more than sufficient instability and shear in place,
the afternoon and early evening severe threat in this region is
highly conditional given uncertainties about whether dryline
storms will even develop.

Additional thunderstorms should develop during the mid to late
evening hours across parts of eastern Oklahoma and western
Arkansas in advance of the cold front with the increasing low
level jet. There is some potential for activity to go along the
cold front itself as well. Even the overnight thunderstorms should
maintain a cellular structure, especially ahead of the cold front,
with continued tornado potential given the very strong low level
shear. Thunderstorms will likely be mostly east of the forecast
area by 3 to 4 am and certainly by sunrise Wednesday morning.

Rewinding to this afternoon, strong mixing across parts of
northeast Oklahoma should lead to low dew points during the
afternoon generally northwest of a Pawnee to Bartlesville line.
With temperatures near 80 and strong south to southwesterly winds,
near Red Flag conditions likely to occur. As a result, we will
issue a Fire Weather Watch this afternoon and early evening,
especially given the continued very dry fuels.

Fire spread potential will also be heightened tomorrow behind the
cold front, with minimum relative humidities from 20 to 25 percent
and northwest winds at sustained speeds around 15 mph.

The rest of the work week and the early part of the weekend should
be fairly quiet with steadily warming temperatures. Some shower
and thunderstorm potential will develop late in the weekend as
moisture returns ahead of an approaching front. Some model
differences exist regarding the handling of this front and
associated upper level trough, with the ECMWF showing a much more
amplified upper pattern and thus, a stronger push of cold, dry
air, than the GFS at this point.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   80  42  60  30 /  20  20   0   0
FSM   77  52  64  33 /  40  60   0   0
MLC   78  46  62  31 /  30  30   0   0
BVO   79  40  60  26 /  20  20   0   0
FYV   73  45  56  27 /  40  60   0   0
BYV   75  47  56  29 /  40  60   0   0
MKO   77  44  62  31 /  30  30   0   0
MIO   76  42  58  28 /  30  40   0   0
F10   79  44  61  32 /  20  20   0   0
HHW   77  50  64  34 /  30  50   0   0

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Fire Weather Watch from noon CST today through this evening for
     OKZ054-055-059.

AR...None.
&&

$$

AVIATION...07


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