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fxus64 ktsa 211816 

Area forecast discussion
National Weather Service Tulsa OK
1216 PM CST sun Jan 21 2018


The discussion for the 18z taf forecast can be found below.


concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm/krog.
Low level moisture in place ahead of an upper storm system is
leading to MVFR cigs at most sites, which will continue off and on
until the cold front arrives this evening. A round or two of
showers and storms will precede the cold front, after which
conditions will return to VFR. Wrap-around cool and relatively
moist air on the back side of the system will bring MVFR cigs to
NE OK and northwest Arkansas sites on Monday. Strong south winds, with gusts to
near 35 knots, will prevail thru the day. Winds will veer to the
southwest or west behind the front tonight. By mid morning on
Monday, deep mixing will allow winds to increase again, with gusts
to 30 or 35 knots possible across NE OK and northwest Arkansas.



Previous discussion... /issued 951 am CST sun Jan 21 2018/


The main updates to the previous forecast were to adjust thunder
and severe probabilities and to insert some low pops this morning
over in the far east. See discussion below.


A fairly vigorous and progressive shortwave trough, evident on WV
imagery over nm/co, will continue to March east toward the plains
today. Southerly flow in advance of the system continues to draw
a semi-moist airmass up into our area from the western Gulf. The
rich moisture remains bottled up well to the south due to a system
moving across Florida. Dewpoints near 60 are observed at Hugo with low
60s in east TX, thus expect low 60s to spread up into far eastern
OK and toward the Ozarks by the end of the day. Still a lot of
disagreement amongst the model suite as to how unstable we get
this afternoon in this moist/Theta-E axis. Ec/GFS continue to
suggest 250-500 j/kg of ml/MUCAPE, while the NAM, which usually is
overdone, has an axis of 1000 j/kg and is farther west than
anything else. As is typical of cool season systems, shear will
definitely be sufficient for severe. Most of the models suggest
development of scattered storms between 21z and 00z in a pre-
frontal convergent zone well ahead of the Pacific front/dryline.
Local models and the operational hrrr do show some updraft
helicity tracks this afternoon along the expected moist axis in
far eastern OK and far western AR, and thus severe probabilities
have been increased in this zone. Isolated tornadoes are possible
as well. Thunder probabilities have been adjusted upward as well.
There is also some suggestion that some scattered storms could
fire this evening along the Pacific front as it sweeps across the
region. The activity should exit the region by around midnight

Finally, some low pops were inserted into the forecast this
morning as showers have popped up on radar over in the vicinity of
the ouachitas and Fort Smith, likely due to warm advection.


Previous discussion... /issued 554 am CST sun Jan 21 2018/

concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm/krog.
MVFR to VFR conditions are common across the area this morning
and this trend is expected to continue through the day. Showers
and thunderstorms are forecast to develop this afternoon and
could possibly impact kmlc and the western Arkansas taf sites
into the evening hours.

Previous discussion... /issued 355 am CST sun Jan 21 2018/

a strong storm system will move out of The Rockies into the plains
today. Gusty southerly winds ahead of this system will continue to
transport unseasonable warmth and moisture northward into our area
today. Similar to Saturday, morning low cloudiness will tend to
dissipate during the late morning to early afternoon time frame,
and temperatures will respond by warming into the upper 60s to
lower 70s. The warm and windy weather will result in a limited
fire danger, with higher fire danger to the west of our area where
surface dewpoints will fall off sharply later this afternoon
following the passage of a dryline.

Showers and a few thunderstorms will develop by mid to late
afternoon, mainly from southeast Oklahoma into northwest Arkansas.
Instability will be limited, but a few strong to severe storms
will be possible during the late afternoon and evening, with
damaging winds being the main severe weather threat.

A cold front will sweep across the area overnight, with gusty west
winds following in its wake Monday. Much drier air will also
overspread the area, making Monday the day of greatest fire
weather concerns in our area, especially where significant
rainfall does not occur later today. Considerable cloud cover
across the northern part of the forecast area may mitigate the
danger to some degree however.

Mild weather will be the rule for much of the upcoming week.
Another storm system will affect the area by late Friday into
Saturday, with the greatest rain chances again across the southern
and eastern part of the forecast area.

Stayed close to guidance temperatures the next couple days.


Preliminary point temps/pops...
tul 72 40 50 29 / 20 10 10 0
fsm 71 43 55 31 / 50 90 0 0
mlc 71 41 54 31 / 40 30 0 0
bvo 71 38 49 26 / 20 10 10 0
fyv 67 40 47 27 / 50 90 10 0
byv 69 42 48 29 / 30 100 10 10
mko 71 40 51 30 / 40 40 0 0
Mio 69 40 47 28 / 40 50 10 10
f10 71 40 52 30 / 20 20 0 0
hhw 71 42 57 32 / 70 70 0 0


Tsa watches/warnings/advisories...

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