Area Forecast Discussion
Issued by NWS Tulsa, OK

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748
FXUS64 KTSA 261106
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
606 AM CDT Fri May 26 2017

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Lower clouds will begin to spread north today with LIFR conditions
after midnight as a frontal boundary stalls just south of I-44.
Thunderstorm chances over NW AR late tonight appear too low to
include in TAF at this time.


&&

.PREV DISCUSSION... /Issued 444 AM CDT Fri May 26 2017/

DISCUSSION...
Early this morning a closed low pressure system was positioned
over South Central Canada with a surface boundary extending
southward through the Northern and Central Plains to the surface
low located over Western Oklahoma. From the surface low...a
dryline extended south southwest into Western Texas. Ahead of
these boundaries...across Eastern Oklahoma and Northwest
Arkansas...breezy southerly winds were keeping temperatures about
15 to 25 degrees warmer compared to 24-hrs ago. These boundaries
will be the main focus for increasing severe potentials over the
CWA into the holiday weekend.

Through today...the surface boundary and associated surface low
will shift eastward into Northeast Oklahoma...close to the
interstate 44 corridor...and become nearly stationary. South of
the boundary...breezy southerly winds will continue to transport
low level moisture into the region with 70+ degree dewpoints
already streaming northward through Eastern Texas this morning.
These conditions will allow for temperatures to climb into the mid
80s to around 90 degrees for the CWA this afternoon with heat
index values in the mid to upper 90s over parts of Eastern
Oklahoma.

Increasing moisture/temperatures will aid in creating an
unstable...however capped...atmosphere over the region. This cap
should limit thunderstorm potential for much of today with a slight
chance of thunderstorms holding off until this evening and
overnight mainly across Northeast Oklahoma and Northwest Arkansas.
Any storm that can develop and overtake the cap will have the
potential to become severe with large hail and damaging wind the
main threats. However...the overall severe potential through
tonight should remain limited with the strength of the cap. An MCS
is expected to develop over Eastern Colorado this evening and
push across the Plains overnight. The southern portion of this
complex could possibly clip part of Northeast Oklahoma and
Northwest Arkansas late tonight into early Saturday morning.

The surface frontal boundary is forecast to remain over Eastern
Oklahoma with the dryline over far South Central Oklahoma during
the day Saturday and begin to push southeast through the CWA
Saturday night as the upper level trof axis...associated with the
closed low in Southern Canada...approaches the region. Continued
70+ degree dewpoints pooling along and ahead of the front and mid
80s to around 90 degree temperatures will aid in a very unstable
atmosphere. Latest model solutions indicate the cap weakening
Saturday mid/late afternoon which will allow for increasing
thunderstorm chances along and ahead of the front across the
northern part of the CWA into Southern Kansas and also along the
dryline in South Central Oklahoma. Storms that develop will likely
quickly become severe with very large hail...damaging winds and
also a tornado threat possible. The tornado potential looks to be
more associated with any storm that can become rooted along any
boundary through the evening hours.

Overnight Saturday night...thunderstorms look to dive
southeastward through the region with the push of a cold front.
This could translate severe potentials into more of a damaging
wind threat...though large hail will still be possible. Periods of
heavy rainfall could also become a concern overnight with 1 to
near 2 inches of rainfall possible over Southeast Oklahoma and
Northwest Arkansas. This could create flash flooding
concerns...especially for people along/near rivers during the
holiday weekend.

The cold front moves through and exits Southeast Oklahoma and
Northwest Arkansas during the day Sunday with the upper level trof
axis progged to push east of the region Sunday night.
Thunderstorm chances will remain possible over these locations
into the afternoon hours Sunday before the front exits to the
east. A limited severe potential will continue into Sunday from
the ongoing thunderstorm activity Saturday night.

Behind the departing system Sunday...more seasonal temperatures
will be possible Monday and Tuesday with thunderstorm chances
returning mid week as another wave looks to drop southeast through
the Plains within the upper level flow of the Southern Canadian
low pressure system. This wave looks to quickly exit with another
wave possibly developing over the West Coast moving into the
Plains late next week. Thus...will keep at least small
thunderstorm chances possible Thursday/Friday for the CWA.

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&

$$

AVIATION...12



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