Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 251745
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1145 AM CST Sun Feb 25 2018

.DISCUSSION...
Aviation discussion for the 18 UTC TAFs is below.

&&

.AVIATION...
VFR conditions are expected now through 18 UTC Monday.

A weak cold front will move south and bring a wind shift to
the north as early as 18 UTC Sunday in northwestern Oklahoma to
as late as 02 or 03 UTC Monday near KSPS.

A few -SHRA may occur across central and northern Oklahoma
21-04 UTC. Chances of occurrence remain too low to mention
in the TAFs.

Brief MVFR or lower conditions with BR may occur at many TAF
sites 09-16 UTC Monday. Chances of occurrence remain too low to
mention in the TAFs.

MBS

&&

.PREV DISCUSSION... /issued 1104 AM CST Sun Feb 25 2018/

UPDATE...
Removed morning fog mention. Lowered afternoon highs a few
degrees in many locations, especially in northern Oklahoma.
Expanded sprinkle mention to include parts of central and northern
Oklahoma late this afternoon and evening. Made some adjustments
to other elements today and tonight.

DISCUSSION...
Warmer weather will occur today.

Highs today will be above average across Oklahoma and western
north Texas. Mid and high level cloud cover will increase in
northern Oklahoma ahead of mid/upper trough that extended across
western Kansas into far southeastern Colorado as of 11 am,
which should limit afternoon heating in northern Oklahoma.
Abundant ground moisture from recent precipitation across much of
Oklahoma and north Texas should limit afternoon heating. Thus,
lowered highs 1-5 degrees in many locations. The exception is far
southwestern Oklahoma and far western north Texas (Altus to
Seymour and points west) where ground conditions remain much drier
from less recent precipitation and think highs will easily reach
the upper 60s to the lower 70s. Surface dewpoints remain tricky
today as latest models seem to be struggling with depicting
abundant ground moisture, very dry air 500-3000 ft AGL, and the
amount of vertical mixing across Oklahoma and north Texas.

Some latest models, particularly HRRR model runs, have been
hinting at light precipitation forming 3-8 pm today across parts
of northern and central Oklahoma, just ahead of the approaching
mid/upper trough as well as along a weak surface cold front.
Deep moisture appears to be lacking (mainly below 12000 ft AGL),
so any rainfall appears to be rather light. Thus, expanded
sprinkle mention to account for this, and kept rain chances around
10% for now. Due to steepening low and mid level lapse rates and
forecast MUCAPE up to 200 J/kg, some of this activity may be
showery in nature. Thunder seems unlikely as most MUCAPE should
be below the -10C level according to latest RAP13 soundings.

MBS

PREV DISCUSSION... /issued 542 AM CST Sun Feb 25 2018/

AVIATION...
25/12Z TAFs. VFR conditions expected to prevail through the
forecast period, outside of brief MVFR restrictions in
shallow/patchy fog few hours of forecast. Wind shift from
southerly to northerly will spread over the region this afternoon
and evening but average winds should stay below 15 knots. There
are hints at some light showers across northern Oklahoma this
evening but no restrictions expected with this low probability so
it will not be included at KPNC this cycle.

PREV DISCUSSION... /issued 406 AM CST Sun Feb 25 2018/

DISCUSSION...
Frosty morning across much of the region this morning, with plenty
of sunshine expected through early afternoon to allow temperatures
to rise above average across the entire forecast area. Very dry air
and warm temperatures will raise the fire weather conditions across
extreme western parts of our northern Texas counties, especially in
those areas that didnt receive appreciable rainfall. Similar to
yesterday, we will issue a fire danger statement where near-critical
conditions for exist for a time this afternoon. Fast moving upper
trough will pass over the region this afternoon and evening.
Although moisture is lacking in the wake of yesterdays system,
highres models are indicating enough moistening and cooling to
develop a small area of showers, and even convection this evening
across far north-central Oklahoma. The NAM and to lesser extent the
GFS are less aggressive but also have this signal as mid-level
thermal trough passes across Kansas and Oklahoma. Confidence not
high enough to make significant changes to going forecast but we
will add mention of at least sprinkles this evening from around Enid
up to Ponca City.

Deeper moisture return commences in earnest Monday into Tuesday.
With approaching long-wave trough, rain chances will increase late
Monday and especially Tuesday through Wednesday. Again, the
greater chances for appreciable rainfall will be over the eastern
half of Oklahoma. There will be enough elevated instability
Tuesday and Tuesday night to support atl east small hail with the
strongest storms. As the mentioned trough begins to eject over the
region Wednesday/Wednesday night, severe storm chances will
increase accordingly. With near neutral to positive tilt to
system, veered flow will yield the main area of rain and strongest
storms south/east of our warning area, similar to our most recent
system. Nothing is locked in yet given timing differences among
the models, but areas that are in most need of rain will likely
miss out again.

Above average temperatures and nil PoPs will dominate the forecast
late in the week into the weekend before another system impacts the
region Sunday into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  60  34  64  44 /  10  10   0  10
Hobart OK         61  30  64  43 /   0  10   0  10
Wichita Falls TX  65  36  64  45 /   0   0   0  10
Gage OK           56  22  64  41 /   0   0   0  10
Ponca City OK     57  28  63  42 /  10  10   0  10
Durant OK         63  40  65  45 /   0  10   0  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

$$

17/23/17



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