077
FXUS64 KOUN 162044
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
344 PM CDT Tue Jul 16 2024

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

.SHORT TERM...
(This evening through Wednesday)
Issued at 343 PM CDT Tue Jul 16 2024

Current Heat Advisory remains in effect through 8 PM with heat
indices currently 105-108 degrees across much of our area.
Storm chances return late this afternoon through tonight across
parts of northern, central, and western Oklahoma with severe storms
possible.

A mid-level shortwave rotating through a synoptic ridge over much of
the Western U.S. will be moving across the Central through Southern
High Plains this evening and across northern OKlahoma late tonight.
Meanwhile further north, a fairly large amplitude trough in the main
jet flow across the U.S. Northern and Central Plains to the Upper
Midwest Regions will be pushing a summertime cold front/surface
boundary across our area.  The surface boundary had been stalled out
across southeast Kansas to the Oklahoma Panhandle but is now
starting to push into far northwest Oklahoma.  Surface & elevated
instability is strong up to 3000-3500 J/kg within the trough where
lapse rates are steeper while slightly weaker to more moderate
values south of the surface boundary in the warm sector.  Deep-layer
shear is marginal across the Central Plains although weakens into
northern Oklahoma so overall our area is in a high CAPE/weak sheared
environment with tonight`s system as far as severity.

We`ll likely see two periods/mechanisms of convection developing,
the first could be triggered by diurnal heating late this afternoon
till sundown in the warm sector extending from I-40 up to the Kansas
state line.  These first round of storms could be more isolated and
short-lived although the environment could produce strong to severe
downburst wind gusts.  The stronger nighttime convection will be the
second round as an MCS associated with the mid-level shortwave
rotating through, with additional surface-based storms along the
cold front when it starts pushing through. Although models have the
MCS activity ramping up after midnight, there could be a brief lull
in the activity after sundown unless the surface boundary starts
pushing through.  This MCS will mainly impact northern Oklahoma with
heavier rainfall and a potential of severe storms. The weak shear
environment should inhibit any organized severe weather but could
still see severe damaging wind gusts as DCAPE values will be
sufficient and can`t rule out some low-end severe hail (quarters)
across far northwest Oklahoma.  Overall, a Marginal risk for severe
storms late this afternoon until after sundown across the northern
two-thirds of our CWA with a 20-30% probability of storm
development. A Marginal to Slight risk across the northern one-third
of our CWA late tonight with a 40-60% probability of storms
developing.  Our CWA should be post-frontal by Wednesday afternoon
with the exiting MCS keeping storm POPs generally along and east of
I-35. Although slightly cooler on Wednesday with temperatures
becoming more seasonable average (90s), not seeing any dry air
behind the front so will still be quite muggy with near 70 degree
dewpoints. Although a stronger cap south of the Red River, diurnal
heating under a weak cap to the north could fire some late afternoon
convection across much of our Oklahoma CWA so will keep low storms
POPs into the evening, although weak surface-based instability
should keep any isolated storms weak should any pulse up.

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 343 PM CDT Tue Jul 16 2024

The upper ridge will persist over the Western U.S. through the
Southern Plains at least through Friday as temperatures should
remain near seasonably average although still humid.  This should
keep our heat indices below triple digits.  As far as rain/storms,
could see another MCS Wednesday night with another shortwave
rotating through the closed ridge although models project that wave
over eastern New Mexico and less impactful in our area.  However, a
weak trough digging into our area could result in some non-severe
elevated storms on Wednesday afternoon and overnight mainly south of
I-40.  South winds return on Saturday with another trough digging
through from the north which could be pushing our next summertime
cold front through on Sunday. Rain/storm POPs will return Saturday
into Sunday and fairly widespread across our area with this weekend
system coming through.  We could see cooler than average
temperatures by Sunday into early next week with highs in the 80s
with less humid air filtering in behind it at least affecting the
western half of our CWA.

&&

.AVIATION...
(18Z TAFS)
Issued at 1125 AM CDT Tue Jul 16 2024

A complex of thunderstorms are expected to move into northern
Oklahoma tonight from the northwest. This will affect TAF sites
across the north half or more of the state. A cold front
associated with the complex will shift winds from south to north
or northeast. VFR conditions are expected through the valid period
at KSPS and KDUA.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  74  89  68  88 /  30  30  20  10
Hobart OK         74  92  68  91 /  20  30  20  20
Wichita Falls TX  79  96  71  92 /   0  20  30  20
Gage OK           69  89  64  88 /  60  30  10  10
Ponca City OK     72  88  66  87 /  60  40  10   0
Durant OK         79  97  71  92 /  10  30  40  30

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 8 PM CDT this evening for OKZ007-008-012-013-
     016>048-050>052.

TX...Heat Advisory until 8 PM CDT this evening for TXZ083>090.

&&

$$

SHORT TERM...68
LONG TERM....68
AVIATION...09