Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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000
FXUS64 KOUN 280539
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1139 PM CST Mon Feb 27 2017

.DISCUSSION...
The 06Z aviation discussion follows....

&&

.AVIATION...
A jagged edge of low ceilings/visibilities will remain near I-35
through Tuesday morning (high clouds west, low clouds/BR/FG
east). During the day Tuesday, winds will turn more into the
southwest, bringing drier air into much of Oklahoma and north
Texas, and clearing most of the low clouds and BR/FG. Winds will
increase Tuesday, especially in the far west, where higher
elevations will allow more effective mixing into strong winds
around 4,000 ft MSL. A cold front will arrive in northwest
Oklahoma around 01/0000Z, and will then sweep rapidly to the
southeast overnight.

CmS
&&

.PREV DISCUSSION... /issued 908 PM CST Mon Feb 27 2017/

UPDATE...
Main changes with update were to add fog to grids. Added late
this afternoon for southeast Oklahoma and this update will spread
mention of fog into much of central Oklahoma for the overnight and
early Tuesday morning period. Some dense fog will be possible
mainly east of I-35.

Will leave low pops across southeast Oklahoma through midnight per
radar and satellite trends as elevated showers and storms still
possible.

PREV DISCUSSION... /issued 534 PM CST Mon Feb 27 2017/

DISCUSSION...
The 00Z aviation discussion follows....

AVIATION...
A few TSRA may still occur in southeast Oklahoma this evening, but
none are expected at our TAF sites. Very low ceilings over eastern
Oklahoma may expand west enough to reach KPNC or KOUN, but more
likely is a layer closer to 1,500 ft toward 04-06Z, mainly along
and east of I-35. These clouds should be shunted east tomorrow
morning as strong south-southwest winds develop in a tight
pressure gradient. Winds will be quite strong over parts of
western Oklahoma Tuesday afternoon, where vertical mixing will
tap into very strong winds at the 850 mb level. A cold front will
arrive in northwest Oklahoma shortly after the end of this TAF
period, then sweep rapidly southeast during the overnight/early
morning on Wednesday.

CmS

PREV DISCUSSION... /issued 402 PM CST Mon Feb 27 2017/

DISCUSSION...
Primary forecast concerns are fire weather conditions/severe
weather potential for tomorrow.

Isolated showers/storms will remain possible across southeast
Oklahoma this morning within an area of isentropic ascent, but
expect coverage to remain limited. Otherwise, expect widespread
stratus to develop later tonight--generally along and east of
I-35.

For tomorrow, a mid/level trough with a 90+ knot mid-level jet
will eject into the Southern Plains. Strong (50-60+ knot),
veering, 850-700 mb winds will allow the dryline to mix eastward
as a surface low tracks eastward across southern Kansas.

Deep mixing behind the dryline will allow these strong winds
above the surface to (partially) mix to the surface. Expect wind
gusts >45 mph near the 100th meridian. Unseasonably warm
temperatures are expected with a low-level thermal ridge in place.
The only caveat that may slightly temper high temperatures is
abundant high clouds. Nevertheless, the aforementioned synoptic
pattern will result in critical to extreme fire weather
conditions. More details in the fire weather section below.

Strong to severe thunderstorms are still possible across eastern
Oklahoma, where a very moist airmass is expected. Dewpoints will
be in the 60Fs, which will result in 1000-1500 J/kg of MLCAPE.
In addition, effective bulk shear is progged to be >60 knots.
This combination of instability and shear will be more than
sufficient for strong to severe thunderstorms. Currently, it
appears the best chance of storms will be just east of I-35.

A cold front will pass by tomorrow evening into tomorrow night
with gusty northerly winds. Expect a return to more seasonable
temperatures in its wake on Wednesday. As a surface ridge shifts
into the Southern Plains, many locations may see a freeze Thursday
morning.

A warming trend is expected into next weekend as southerly winds
return across the area. Temperatures are expected to be well-above
average by Sunday as another low-level thermal ridge develops
across the Southern Plains.

Mahale

FIRE WEATHER...
Upgraded part of the Fire Weather Watch to a Red Flag Warning
where there is the greatest confidence for extreme to critical
fire weather conditions Tuesday afternoon.

Both the GFS the latest HRRRX also indicate there might be a
corridor of drier air near the I-44 corridor between the dryline
and cold front. This area coincident with the location of a low-
level thermal ridge. There is some uncertainty how far east this
corridor may make it; however, expanded the Fire Weather Watch
farther east into Central Oklahoma to account for the uncertainty.

Will maintain a 9 PM expiration time; however, there is the
possibility that an extension will be needed if critical fire
weather conditions continue past 9 PM--especially because of the
strong northerly shift that will pass by Tuesday evening.

Mahale

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  59  77  40  59 /  10  10  10   0
Hobart OK         51  77  37  60 /   0   0   0   0
Wichita Falls TX  57  81  42  62 /  10  10   0   0
Gage OK           50  75  31  57 /   0  10  10   0
Ponca City OK     56  77  37  57 /  10  10  10   0
Durant OK         62  76  47  63 /  30  30  40   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Fire Weather Watch from Tuesday afternoon through Tuesday
     evening for OKZ005-006-011-012-017>019-023>025-027>029-038-
     039-044-045.

     Red Flag Warning from noon to 9 PM CST Tuesday for OKZ004-009-
     010-014>016-021-022-033>037.

TX...Fire Weather Watch from Tuesday afternoon through Tuesday
     evening for TXZ086-089-090.

     Red Flag Warning from noon to 9 PM CST Tuesday for TXZ083>085-
     087-088.

&&

$$

11/23/23


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