249
FXUS64 KTSA 161127
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
627 AM CDT Fri Aug 16 2024

...New AVIATION...

.SHORT TERM...
(Today)
Issued at 400 AM CDT Fri Aug 16 2024

Residual showers and thunderstorms continue to push southeastward
across portions of southeast OK early this morning. This activity
is being fueled by modest low-level WAA/low-level jet overrunning
an outflow boundary/cold pool from a complex of storms that
rolled through parts of northeast OK earlier in the evening. These
elevated storms should dissipate over the next hour or so as the
boundary layer should become more stable.

The main focus for today will be on the dangerous heat and
humidity that will plague much of eastern OK and northwest AR
this afternoon. Potent mid/upper-level ridging over the Desert
Southwest will further intensify and will begin to expand across
the Southern Plains through the day. Daytime high temperatures
will soar into the upper 90s and lower 100s in most locations this
afternoon. Meanwhile, a plethora of low-level moisture and WAA
will be in place across the region ahead of a quasi-stationary
surface boundary along/near the OK/KS border. This frontal
boundary is expected to remain nearly stationary over the next 24
hours or so. Widespread dewpoints in the 70s will be common
through much of the daytime today. As a result, heat indices and
wet bulb globe temperatures are forecast to be exceptionally high
today. With that said, was confident enough to upgrade all of
southeast OK to an Excessive Heat Warning today. The rest of the
heat headlines from the previous forecast remains unchanged.

The Storm Prediction Center has contoured a Slight Risk of severe
thunderstorms in their 06z update of their Day 1 Convective
Outlook for portions of the forecast area today, mainly north of
the I-40 corridor, with a Marginal Risk surrounding the Slight
Risk. Although the majority of the severe threat is expected to
occur this evening/tonight, isolated thunderstorms are anticipated
to develop just after peak heating late this afternoon, with
storm initiation focused near or just ahead of the stationary
frontal boundary. Steep low/mid-lapse rates underneath a corridor
of MLCAPE values exceeding 2500+ J/kg will result in storms with
mature updrafts producing large hail and damaging wind gusts which
may continue into the evening hours.

Mejia

&&

.LONG TERM...
(Tonight through Thursday)
Issued at 400 AM CDT Fri Aug 16 2024

Strong to severe thunderstorms are expected to increase in
coverage this evening/tonight as a mid-level shortwave trough
slides off the High Plains and rides the northern fringe of the
upper ridge and approaches the forecast area. Bulk shear (0-1km &
0-6km) will rapidly increase as the wave approaches. Steep low-
level lapse rates from earlier in the day will remain in place
through the evening. As a modest low-level jet develops after
sunset, storms should grow upscale, with an MCS forecast to
develop and move across portions of the forecast area late tonight
and possibly through the overnight hours. Large hail and strong
damaging wind gusts will be the main threats with the convection.
With exceptionally high DCAPE values produced by CAMs, would not
be surprised if a few storms produced wind gusts in excess of 70
mph. PoPs may need to be adjusted through the day today as updated
short-range models/CAMs get a better grasp of the setup this
evening/tonight. In addition to the severe threat, moderate to
heavy rain may accompany the storms. Heavier storms/stronger
updrafts will be capable of producing minor flooding and perhaps
isolated flash flooding.

Hot and humid weather will persist on Saturday as the
aforementioned stationary surface frontal boundary begins to
slide southward some during the daytime on Saturday. Guidance
shows the frontal boundary pushing south of I-40 by Sunday morning
where it seems to stall again in far southeast OK by Sunday
afternoon/evening. Nevertheless, additional heat headlines look to
be needed both on Saturday and again on Sunday for portions of the
forecast area. The frontal boundary will gradually sag south of
the Red River by Monday, with widespread unseasonably cooler
temperatures through at least the first half of next week. Despite
the strong ridge over the Southern Plains this weekend (before
retrograding westward early-mid part of next week), guidance
suggests almost a daily chance of showers and thunderstorms as the
forecast area remains in a north-northwest flow/deformation zone
aloft, with ridging to the west and and deepening trough to the
east of the area. For now, kept the conservative NBM solution for
PoPs. These PoPs will likely need to be adjusted in the upcoming
days.

Mejia

&&

.AVIATION...
(12Z TAFS)
Issued at 626 AM CDT Fri Aug 16 2024

VFR conditions will prevail through the day today. Scattered
thunderstorms will become more likely this evening into the early
part of the overnight hours, with ceiling and visibility
reductions expected in storms.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   99  76  98  75 /  10  30   0  10
FSM  101  77 100  78 /  10  20   0  10
MLC  100  76 102  76 /  10  10   0   0
BVO   98  71  97  70 /  20  40   0  10
FYV   97  72  96  72 /  10  50  10  10
BYV   97  70  95  69 /  10  50  10  10
MKO   98  75  99  75 /  10  20   0  10
MIO   97  70  95  70 /  10  70  10  10
F10   99  74 101  74 /  10  10   0  10
HHW  102  77 102  78 /   0   0   0   0

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from noon today to 9 PM CDT this evening for
     OKZ054>059-062-063-068-069.

     Excessive Heat Warning from noon today to 9 PM CDT this evening
     for OKZ049-053-060-061-064>067-070>076.

AR...Heat Advisory from noon today to 9 PM CDT this evening for
     ARZ001-002-010-011.

     Excessive Heat Warning from noon today to 9 PM CDT this evening
     for ARZ019-020-029.

&&

$$

SHORT TERM...67
LONG TERM....67
AVIATION...05