Wildfire in Oklahoma, December 15 to 16, 2021

Area Forecast Discussion
National Weather Service Tulsa OK
Issued by National Weather Service Norman OK
555 AM CST Wed Dec 15 2021

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 442 AM CST Wed Dec 15 2021

An intense mid-level (500 mb) shortwave trough, currently located
across the Four Corners, is forecast to lift into the Plains by
early this afternoon. The forecast wind fields from the surface to
500 mb are quite impressive with ~120 knots at 500 mb, >80 knots
at 700 mb, and >60 knots at 850 mb. These wind maxima are progged
remain northwest of the of our area (across Kansas), which will
keep the more substantial wind gusts to our northwest.

At the surface, a low will deepen across northeast Colorado and
accelerate across Nebraska. As the low deepens, a tightening
surface pressure gradient will result in breezy southerly winds.
Vertical mixing/momentum transfer from stronger winds aloft will
allow for wind gusts >40 mph. Therefore, the ongoing Wind
Advisory was maintained. Isentropic ascent and moisture advection
ahead of the trough should result in broken cloud cover today.
There may even be a few showers across southeast Oklahoma and
western Arkansas this morning. Mixing here should not be as
substantial as locations to the northwest given the expected cloud
cover (i.e., less insolation).

In the warm sector (ahead of the trough and low), an unseasonably
warm and humid air mass is ongoing across the Southern Plains.
Temperatures this morning are running ~15 to 20 deg F above the
average highs for mid-December in our area. Even with the expected
cloud cover, near record temperatures are forecast for this
afternoon (given the warm start).

By late afternoon/early evening, a trailing pre-frontal trough
(or essentially the dryline) is progged to approach northeast
Oklahoma. The cold front/northerly wind shift will initially lag
behind, but should eventually catch up to the trough/dryline.
Ahead of the boundary, a rather stout cap is forecast with
significant convective inhibition. Therefore, any convection is
initially expected to be associated with convergence along the
boundary. Convection is expected to develop just northwest of
I-44 around 00Z.

Instability (MUCAPE at ~500 to 800 J/kg) and shear (WBWD ~35 to
45 knots) may support few strong to perhaps severe thunderstorms.
However, the significant convective inhibition and mid-level flow
quasi-parallel to the boundary (i.e., more storm interactions)
should temper the severe weather risk. As a matter of fact,
convective-allowing models indicate convection may become more
disorganized by late evening/overnight as it continues to move
southeastward. Increasing isentropic ascent may allow for
convection ahead of the main zone of convection during the
overnight hours as well.

Mahale/WFO OUN

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 442 AM CST Wed Dec 15 2021

The aforementioned front is progged to stall across northeast
Texas/far southeast Oklahoma as the the shortwave trough quickly
lifts into Canada. There will be a low chance for convection
across far southeast Oklahoma during the day Thursday (in close
proximity of the remnant frontal boundary). Otherwise, most
locations should remain dry. The air mass behind the cold front
will be cooler, but still above-average for mid-December. Highs on
Thursday will range from the low 60s across the north to the low
70s deg F across the south.

By Thursday night into Friday, increasing lee
cyclogenesis/pressure falls to the west will result in the front
lifting back to the north as a warm front. Convection is likely on
Friday in close proximity of the warm front. There remains some
uncertainty on how far to the northwest the warm front will
retreat (i.e., will it make it as far northwest as I-44?). For
now, opted to keep rather broad probabilities with the highest
probabilities southeast of I-44 across southeast Oklahoma and
western Arkansas. Precipitable water values are decent for mid-
December (~1.5"), so some locations may get appreciable rainfall.
Instability will be sufficient for thunderstorms as well (perhaps
some strong ones).

By later Friday, as another shortwave trough passes by to the
north, a second, reinforcing cold front will move through the
area. Convection may increase across the southeast as this front
progresses through the area. The air mass behind this front is
colder, which should result in near to even slightly below average
temperatures for Saturday. A widespread hard freeze is expected
Sunday morning with the surface ridge in close proximity.

Temperatures should moderate early next week as the surface ridge
moves to the east. Probabilities for rain may have to be
introduced early next depending on the track of a closed-low that
may open up and lift into the Southern Plains--however confidence
remains low at this time.

Mahale/WFO OUN

&&

.AVIATION...
(12Z TAFS)
Issued at 555 AM CST Wed Dec 15 2021

MVFR ceilings have really started to increase over E OK and NW AR
over the last hour or so after holes were observed in the clouds
allowing ceilings to bounce through the night. Winds just off the
surface across mainly NE OK continue to be gusty with winds likely
in the 35 to 50kt range thus a WS group was maintained for those
locations for much of the morning. At the surface, winds will pick
up this afternoon with gusts exceeding 30kts at all TAF sites
(with the exception of KFSM) at times this afternoon thanks to a
strong storm system moving across the central plains. Winds will
noticeably weaken around sunset. Ceilings will show gradual
improvement through the morning and afternoon as surface
temperatures warm. Our E OK TAF sites stand the best chance to see
VF cigs this afternoon while NW AR will likely stay high end
MVFR. Ceilings may briefly fall this evening ahead of an
approaching cold front and associated line of showers and storms.

A cold front will approach the area this evening and overnight.
This will give all of our terminals a chance for a brief window of
showers and thunderstorms starting between 01 and 03Z for KBVO
with KFSM likely the last terminal to see activity between 08 and
12Z. Conditions will fall into the MVFR category (locally IFR
possible) as storms pass. Low clouds are expected to clear out
relatively quickly immediately behind this activity with mid to
high level clouds lingering behind.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   78  46  59  44 /  10  60   0  40
FSM   77  59  68  56 /  20  80  50  80
MLC   76  53  66  52 /  20  80  30  60
BVO   76  42  57  37 /  10  70  10  20
FYV   74  50  62  49 /  20  90  20  80
BYV   74  50  61  47 /  20  90  30  80
MKO   75  49  61  48 /   0  90  10  60
MIO   74  45  57  43 /  10  70  10  40
F10   77  48  61  47 /   0  80   0  50
HHW   76  60  70  59 /  20  50  60  60

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Wind Advisory until 6 PM CST this evening for OKZ054>076.

AR...Wind Advisory until 6 PM CST this evening for ARZ001-002-010-011.

&&

SHORT TERM...99
LONG TERM....99
AVIATION...99

Hazardous Weather Outlook
National Weather Service Tulsa OK
Issued by National Weather Service Norman OK
522 AM CST Wed Dec 15 2021

ARZ001-002-010-011-019-020-029-OKZ049-053>076-161130-
Adair OK-Benton AR-Carroll AR-Cherokee OK-Choctaw OK-Craig OK-
Crawford AR-Creek OK-Delaware OK-Franklin AR-Haskell OK-Latimer OK-
Le Flore OK-Madison AR-Mayes OK-McIntosh OK-Muskogee OK-Nowata OK-
Okfuskee OK-Okmulgee OK-Osage OK-Ottawa OK-Pawnee OK-Pittsburg OK-
Pushmataha OK-Rogers OK-Sebastian AR-Sequoyah OK-Tulsa OK-Wagoner OK-
Washington OK-Washington AR-
522 AM CST Wed Dec 15 2021

This Outlook is for Northwest and West Central Arkansas as well as
much of Eastern Oklahoma.

.DAY ONE...Today and Tonight.

SEVERE THUNDERSTORM.
	RISK...Limited.
	AREA...North of a line from near McAlester Oklahoma to Poteau Oklahoma.
	ONSET...This evening.

HEAVY RAIN.
	RISK...Limited.
	AREA...Mainly northeast of a line from Okmulgee to McAlester Oklahoma.
	ONSET...Mid evening.

SIGNIFICANT WINDS.
	RISK...Elevated.
	AREA...Mainly northeast Oklahoma and far northwest Arkansas.
	ONSET...Mid-morning.

FIRE WEATHER DANGER.
	RISK...Elevated.
	AREA...Mainly west of Hwy 75 across Osage and Pawnee counties.
	ONSET...Mid to late afternoon.

DISCUSSION...

Gusty southerly winds are expected today. Winds are expected to
exceed 40 miles an hour at times, especially across northeast
Oklahoma. This will result in elevated fire weather conditions,
especially across Osage and Pawnee counties. A cold front is
expected to move through this evening, bringing chances for
showers and thunderstorms. Some of these storms may be strong to
perhaps severe.

SPOTTER AND EMERGENCY MANAGEMENT ACTION STATEMENT...
Spotter Activation May Be Needed.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.
THURSDAY...Thunderstorm Potential.
FRIDAY...Thunderstorm Potential...Heavy Rain Potential.
SATURDAY...No Hazards.
SUNDAY...No Hazards.
MONDAY...No Hazards.
TUESDAY...No Hazards.

EXTENDED DISCUSSION...
The cold front is expected to stall over far southeast Oklahoma
or northeast Texas, where it will linger Thursday before migrating
north Friday. Locally heavy rainfall may be a concern with storms
expected Friday. Another strong cold front will then swing
through the area late Friday and Friday night bringing additional
chances for thunderstorms and heavy rainfall. Some of these storms
may be strong to perhaps severe.

weather.gov/tulsa contains additional information.

Mahale