398
FXUS64 KTSA 211912
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
212 PM CDT Sat Sep 21 2024

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

.SHORT TERM...
(Through Tonight)
Issued at 212 PM CDT Sat Sep 21 2024

Another abnormally hot and humid day has transpired across much
of eastern OK and northwest AR. Latest observations around the
region show temperatures have already climbed into the mid-upper
90s in many locations. Heat indices will hover around 105F
through the rest of the afternoon. A Heat Advisory remains in
effect for much of eastern OK and west-central AR through 6 PM
this evening. Upper-level ridging responsible for this
unseasonably hot weather from the past few days will begin to
breakdown and shift southeastward this evening into tonight as a
vigorous upper- trough/low moves over the Rockies and eventually
over the Plains by Sunday morning. Preceding this, CAM guidance
continues to suggest a few isolated showers and storms (10-20%
chance) developing/moving along the flow of the upper-level ridge
through sunset this evening, mainly impacting areas of far
northeast OK and far northwestern AR. Severe weather is not
expected, but any storms that do form may result in locally strong
gusty winds and brief heavy rain.

Mejia

&&

.LONG TERM...
(Tomorrow through Saturday)
Issued at 212 PM CDT Sat Sep 21 2024

A pattern shift will commence Sunday as a positively tilted
trough ejects off the Rockies and moves over the Central/Southern
Plains. In response, a plethora of mid/high clouds will overspread
the forecast area from northwest to southeast through the day. At
the surface, a modest cold front, with considerably cooler and
drier air behind it, will begin to move into the northwest part of
the CWA by mid-morning, pushing southeastward through the area by
early Monday morning. Isolated to scattered elevated showers and
thunderstorms are expected to be ongoing along and ahead of the
frontal boundary Sunday morning, mainly affecting far northeast
OK, near the KS border. As the front continues to advance
southeastward, daytime heating ahead of the front should increase
instability in the afternoon (MLCAPE increasing between 1000-1500
J/kg). Given a moist boundary layer underneath 40-50 knots of
0-6km bulk shear, a few strong to marginally severe thunderstorms
look probable along and ahead of the front, with the highest
threat occurring north of I-40 in OK and into far northwest AR.
The primary hazards with any organized storm/cluster of storms
will be damaging wind gusts and locally heavy rainfall that may
lead to flooding, though small hail will also be possible.
Guidance suggests the threat of severe thunderstorms lowers after
sunset. Overall rainfall amounts through Monday should generally
be less than an inch, though localized heavier amounts may occur.

As mentioned in the previous forecast discussion, forecast high
temperatures are still somewhat uncertain on Sunday, especially
north of I-40, and will be highly dependent on frontal
timing/position and rainfall prior to peak heating. Particularly,
north of I-44, temperatures may struggle to reach 80 degrees if
the front is faster than forecast. Elsewhere, and especially
across southeast OK and west-central AR, afternoon temperatures
ahead of the front should rise into the low-mid 90s. The front
will exit the forecast area by early Monday morning. Significantly
cooler temperatures are expected on Monday as thick cloud cover
and precipitation lingers behind the front. Showers and
thunderstorms should gradually diminish from west-to-east through
the day Monday as the upper-level trough shifts east of the area;
dry conditions are forecast by Monday evening/night.

There is still a lot of uncertainty with regards to the synoptic
pattern beyond Monday. Consensus in global models and ensembles
indicate a secondary upper-level trough/low developing over the
Plains behind the initial trough by midweek, but how it evolves
and where it tracks is highly uncertain at this time. At the
moment, it appears slightly cooler to near average temperatures
and slightly above normal rainfall is favored through the second
half of the week and into next weekend.

Mejia

&&

.AVIATION...
(18Z TAFS)
Issued at 1203 PM CDT Sat Sep 21 2024

VFR conditions remain the expectation for much of the forecast
period. A few possible exceptions would be a low chance of storms
across far NW AR terminals this afternoon, patchy fog across
western AR overnight, and additional showers and storms spreading
into NE OK late tonight through mid Sunday morning. These
scenarios continue to have low chances of impacting flight
conditions at any specific terminal.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   75  87  61  72 /  20  60  80  30
FSM   75  93  70  78 /   0  20  40  60
MLC   74  94  62  77 /   0  20  50  50
BVO   69  83  56  72 /  30  70  70  20
FYV   71  90  64  75 /  10  30  60  70
BYV   71  90  66  73 /  20  50  60  70
MKO   74  91  61  72 /  10  40  70  50
MIO   71  87  59  69 /  20  70  70  40
F10   73  91  60  74 /  10  40  70  40
HHW   73  93  68  79 /   0  10  20  50

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 6 PM CDT this evening for OKZ049-053>057-
     059>062-064>068-070>076.

AR...Heat Advisory until 6 PM CDT this evening for ARZ019-020-029.

&&

$$

SHORT TERM...67
LONG TERM....67
AVIATION...07