898
FXUS64 KTSA 170839
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
339 AM CDT Sat Aug 17 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today)
Issued at 339 AM CDT Sat Aug 17 2024

Widely scattered strong/severe thunderstorms continue to develop
across far eastern OK and northwest AR early this morning. This
activity is just now showing signs of weakening in comparison to
a couple of hours ago. Latest surface analysis indicates an
extensive outflow boundary from convection in central AR advancing
southward across southeast OK. Warm air advection overrunning the
outflow has generated a few clusters of thunderstorms, which are
riding a 700-500mb moisture axis across far eastern OK/northwest
AR. Sufficient instability, shear, and lift are supporting strong
to severe storms, with large hail and gusty winds being the
primary hazards with this activity. Guidance has the storms
continuing to weaken over the next few hours. Will monitor trends
and amend the near-term grids as necessary. A Severe Thunderstorm
Watch remains in effect for west-central AR as well as Sequoya and
Le Flore counties in OK until 4 AM this morning. Showers and
thunderstorms should continue to decrease in coverage through the
morning, with mostly dry conditions by midday.

Dangerous heat and humidity will once again be the main storyline
today once the precipitation ends. Rainfall from last night/this
morning will likely keep dewpoint temperatures elevated through
the day, especially locations that have received wetting rainfall
over the last 12-24 hours. With ambient air temperatures expected
to rise into the mid-upper 90s and lower 100s, oppressive heat is
likely again today for most locations in the forecast area. Have
included far northwest AR in a Heat Advisory and upgraded portions
of west- central AR/northeast OK in an Excessive Heat Warning,
both of which go into effect from noon until 9 PM tonight.

Mejia

&&

.LONG TERM...
(Tonight through Friday)
Issued at 339 AM CDT Sat Aug 17 2024

Strong mid/upper-level ridging will slide eastward over the TX/OK
Panhandles by this evening/tonight. Meanwhile, a fairly deep
upper-level trough will further deepen along the east coast of
the US through the rest of the weekend. This will result in
eastern OK/northwest AR being in a deformation zone of NNW flow
aloft. Models and ensembles show this pattern persisting through
at least the first half of next week. Closer to the surface,
modest warm air advection is forecast to continue affecting the
region through the remainder of the weekend. Heat headlines look
likely to be needed again on Sunday for most locations. Better
details on this will come in the next forecast package.

On Sunday, surface high pressure is expected to move into the
Northern/Central Plains from Canada, positioning itself over the
Upper Midwest by Sunday night/Monday morning. As this occurs, the
surface high will gradually push a backdoor frontal boundary
through the area during the daytime Sunday, with the front pushing
south of the Red River late Sunday night or early Monday morning.
Following the front, guidance shows temperatures dropping
slightly below or near seasonal average through midweek, with a
gradual climb in temperatures by late next week as ridging begins
to build back over the Plains.

Low-end precipitation chances will occur almost daily for at
least some portions of the forecast area into midweek. Medium-
range models indicate chances "maximize" along/near the
aforementioned shear axis/deformation zone aloft. The best chance
(30-50%) of precipitation in the long-term period will occur
Sunday afternoon/evening and into the overnight hours in
association with the frontal boundary that will be moving through
the area. The Storm Prediction Center has included most of the
forecast area in a Marginal Risk for severe thunderstorms Sunday
as there should be sufficient instability, shear, and lift along
the front to spark a few strong to severe storms. Sporadic low
chances of precipitation will linger Monday, Tuesday, and possibly
into Wednesday before upper-level ridging repositions itself over
the Southern/Central Plains and essentially end chances through
the remainder of the forecast period.

Mejia

&&

.AVIATION...
(06Z TAFS)
Issued at 1142 PM CDT Fri Aug 16 2024

Well defined cold pool has spread across NE OK / NW AR from
evening storms. This boundary may be sufficient for the S-SW
overnight low level jet to maintain scattered storm development
and forecast will mention potential thunderstorm impacts for all
terminals. Precip cover expected to wane by mid to late morning
with VFR conditions then prevailing. Storms may again develop
Saturday night but current guidance suggests this potential is
more likely just beyond this forecast valid time.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   99  76  97  74 /  10  10  10  20
FSM  100  77 100  75 /  50   0  10  30
MLC  101  77 102  76 /  20   0  10  10
BVO   97  72  95  70 /  10  10  10  30
FYV   95  72  95  69 /  50  10  20  40
BYV   94  71  93  67 /  40  10  20  40
MKO   96  76  99  74 /  30   0  10  20
MIO   94  71  94  68 /  30  10  20  40
F10   98  75 101  74 /  20  10  10  10
HHW  102  77 105  77 /  10   0   0   0

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from noon today to 9 PM CDT this evening for
     OKZ054-058-059-063-068-069.

     Excessive Heat Warning from noon today to 9 PM CDT this evening
     for OKZ049-053-055>057-060>062-064>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...07