NWS Area Forecast Discussion

FXUS64 KFWD 161040 AAA

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
540 AM CDT Thu Sep 16 2021

...New Short Term, Aviation...

/Through Thursday Morning/

No major changes from the earlier discussion below. A broad mid
level disturbance dropping south across SW OK/NW TX, is producing
some high-based Cu and/or AC across areas N of I-20 attm. This
layer of moisture is relatively thin and no precipitation is
occurring or expected at this time. There is a band of stratus
from the leftovers of Nicholas that is advecting west from LA and
SE TX per current satellite IR imagery. This shallow and low level
moisture should make it as far west as parts of our CWA,
particularly locations E of I-35/35E and south of I-30 later this
morning. If this deck doesn`t mix/scatter as much as currently
anticipated later this morning, then high temperatures may need to
be lowered. No precipitation is expected.

Otherwise, look for above normal high temperatures to continue in
the upper 80s to mid 90s, with increasing surface dew point
temperatures helping to keep lows up Thursday morning a few
degrees higher.


Previous Discussion:
/Pre-Dawn through Tonight/

Earlier showers near the Red River have dissipated and now leave
only a scattering of mid level clouds across North Texas. A strong
radiation inversion has developed across the area thanks to mostly
clear skies and light to calm winds. Radiational cooling should
allow many rural locations to fall to within a few degrees of the
dew point temperature this morning. An area of stratus over deep
southeast Texas may creep into our southeasternmost counties in
the early morning hours, but mostly clear skies should be the norm
this morning.

The area will be under the influence of an induced surface ridge
today between the deepening leeside trough to our west and the
remnant tropical depression to our east. This should keep the
weather quiet with a mundane CU field this afternoon. Afternoon
highs should be about the same as they were yesterday +/- a degree
or two.

The remnants of the tropical depression will finally begin to give
up hold of the region tonight into Friday. As the surface low
fills, the flow shifts out of the southeast and begins advecting
higher moisture air back into the region. This should bump up the
overnight lows with most of the area hovering in the low to mid
70s by the time Friday morning rolls around.



.LONG TERM... /Issued 337 AM CDT Thu Sep 16 2021/
/Moving Into The Weekend Through Mid Week/

A mid level impulse currently drifting south over Wrn OK will
become cut off right over our area on Friday, before continuing
southeast toward the Upper Texas Coast/NW Gulf of Mexico this
weekend. Progression of this feature will dictated by an amplifying
shortwave ridge to our immediate west as a broad trough detaches
just off the CA Coast this weekend. The more intensive stream will
be well displaced to the north of our area from the northern tier
of the U.S. and Southern Canada as we slowly wind down the last
week or so of astronomical Summer. With the stronger mid level
zonal flow being so displaced north, stronger lee side pressure
falls will be displaced further north as well. The pressure
gradient and winds across the region will remain relatively weak.

The expected southeast trajectory of the broad mid level low will
keep the richest PWAT fields mostly east of our area, from Ern TX
through the Deep South. Considering the southeastward drift of
this feature toward the NW Gulf through the weekend, the combination
of heating with subtle ageostrophic-isallobaric ascent off the
east side of this feature. Surface features and lifting mechanisms
will be generally absent or very benign, so will only advertise
low convective rain chances across Ern Central TX and our far
eastern counties each afternoon and early evening with peak
heating. High temperatures will be above normal for all except
possibly our Ern TX counties (normals are generally mid-upper 80s
for mid September), as the shortwave ridge continues to build
across the western Southern Plains and High Plains. Highs will
range from the mid- upper 80s across East Texas, to the lower-mid
90s along and west of I-35/35W with the toastiest readings and
lower humidity values occurring across the Big Country west of

The above normal heat continues into early next week, as a broad
upper ridge continues across the Southern Plains in advance of an
impressive and deep, full latitudinal longwave trough evolving
from the Canadian Rockies all the way down into the Central
Rockies and eventually the High Plains moving into next Tuesday
and Wednesday. This is where the forecast upper pattern becomes
more challenging, as it transitions more toward an early Fall
pattern. Coincidentally, this will be occur just as we happen upon
the Fall Equinox on the 22nd (Wednesday). Being we`re almost a
week out and considering the depth of this mid level energy,
deterministic models can definitely struggle and I tend to want to
lean on more of the ensemble means of the GEPS, EPS, and GEFS
means. Believe or not, the deterministic versions on the latest
00z runs are actually in good agreement on the development and
eastward progressive nature of this deep mid level feature and
driving a strong cold front (with an airmass originating from the
Yukon territory of far NW Canada) through our area sometime
Wednesday(GFS) or Wednesday night/Thursday morning (ECMWF).

Either way, confidence is increasing on a strong cold front and
cooler/drier airmass arriving into the area around the middle of
next week and just in time for the start of astronomical Fall. As
for convective chances, we continue to keep them on the low side
(20-30%) considering better kinematics/dynamics with a jet streak
will be displaced well north of the area across the Central
Rockies/Plains, then into the Mid MS Valley, Great Lakes, and OH
valley late in the week. Brief low level warm advection right
above the surface in advance of the surface cold front and upper
trough does a brief window for elevated moisture return. Combined
with forcing from the surface cold front and height falls with
this upper trough that a few storms are likely. Regarding any
severe weather threat, it`s way to early to assess what our
thermodynamic environment will be like which would likely be the
primary driver for storm intensity, as stronger winds aloft and
associated wind shear also will remain well north of the area.
Regardless, cooler and eventually less humid weather appears is
appearing on the horizon. Forecast highs in the lower to mid 80s
will begin on Wednesday, while morning lows in the upper 50s and
60s will begin Thursday morning and should last into early the
following weekend.



/12z TAFs/

Only change from the 06z aviation discussion below is we are
watching a stratus deck moving wwd from LA and SE TX toward the
D10 and Waco Regional Airport. This may result in some brief/
TEMPO MVFR cigs at Waco Regional later this morning. Right now,
confidence appears too low with mixing and heating for any issues
across the D10/DFW Metro airports. Light n` variable winds to
start the forecast will become light E or ESE 10 kts or less after
15z. No precipitation is expected, despite a broad upper level low
dropping south out of Wrn OK attm.


Previous Discussion:
/06Z TAFs/

Light and variable winds should continue through much of the night
with a subtle shift out of the southeast in the early morning
hours. An area of MVFR ceilings should develop over deep Southeast
Texas which may creep into Eastern Central/North Texas, but we do
not anticipate any ceilings over ACT/D10 ATTM. A light southeast
wind early in the day should give way to east-northeast winds in
the afternoon under a VFR CU field.



Dallas-Ft. Worth    91  72  94  73  94 /   0   5   5   0   0
Waco                90  70  95  71  93 /   0   0   5   0   5
Paris               88  70  90  70  88 /   5   5  30  20  10
Denton              91  68  93  69  92 /   0   0   5   0   0
McKinney            90  69  92  70  92 /   0   5  10   5   5
Dallas              91  74  93  75  93 /   0   5   5   0   5
Terrell             90  69  92  71  90 /   5   5  10  10  10
Corsicana           89  71  93  73  90 /   5   5  10   5  10
Temple              91  69  95  69  92 /   0   0   5   0   5
Mineral Wells       90  67  93  68  93 /   0   0   5   0   0




NWS FWD Office Area Forecast Discussion