000
FXUS64 KFWD 271118
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
618 AM CDT Sat Apr 27 2024

...New Short Term, Aviation...

.SHORT TERM... /NEW/
Update:

A few warm advection showers have developed across East Texas and
southern Oklahoma, but no lightning has been observed as of now.
Well to our west, convective initiation is beginning to take
place. Most of these storms should remain to our northwest, but
they will send a cold pool/outflow boundary south that may ignite
additional storms late this afternoon across Western North Texas.

We still have low confidence regarding storms developing in the
open warm sector (i.e. away from the dry line) this afternoon.
Forecast soundings tend to indicate the cap eroding between
21-23Z, but time will tell if this comes to fruition. If the cap
does erode, scattered severe storms capable of all modes of severe
weather will be likely. Our confidence of an evening and overnight
line of storms remains high at this time.

Much more detail regarding the forecast can be read below.

Bonnette

Previous Discussion... /Issued 225 AM CDT Sat Apr 27 2024/
/This Weekend/

A severe weather outbreak is possible this afternoon and tonight.
 - Very large hail 2+" in diameter, damaging wind gusts upwards of
   70+ mph, and tornadoes are most likely in the late afternoon
   and early evening across North Texas (mainly along and west of
   I-35).

 - A line of storms is then expected overnight, bringing the
   potential for damaging wind gusts and spin-up tornadoes across
   most of North and Central Texas.

 - Saturated soils and multiple rounds of heavy rain may lead to
   flash flooding for parts of the area through Sunday afternoon.

 - Outside of thunderstorms, it will be windy. Expect sustained
   south winds of 20-25 mph with gusts upwards of 35-40 mph. The
   strongest winds are expected this afternoon and evening.


Forecast Discussion:
Isolated warm advection showers and perhaps a few thunderstorms
will be possible across North Texas in the pre- dawn hours, but
most of the area will start the weekend dry, warm, and muggy. A
dry line moved into the western part of our forecast area Friday
afternoon and has retreated west into the Big Country. A weak,
leading shortwave trough is forecast to move over the Southern
Plains early Saturday morning, igniting a cluster of thunderstorms
near the dryline around sunrise. Most of this activity should
remain west/northwest of our area. However, depending on where
convective initiation occurs, our far northwestern counties will
have potential to be clipped by some storms early in the day. No
matter where these storms develop/propagate, an outflow boundary
will serve as a focused source of surface ascent sufficient to
overcome any capping/convective inhibition by mid-late morning.

There is uncertainty regarding how far east storms will be able to
advance this afternoon. Some of the 00Z CAM guidance indicated
supercells developing near/in the Metroplex in the open warm
sector along a remnant outflow boundary, while some kept the
stronger cells in Oklahoma and far Western North Texas closer to
the dryline. Either way, supercells supportive of very large hail,
damaging wind gusts, and tornadoes are expected to develop this
afternoon and evening in or near parts of North Texas. There are
only a handful of days each year that I personally ask you to be
weather aware. Today is one of those days.

The warm/moist airmass ahead of the dryline is very positively
buoyant with MLCAPE values over 3000 J/kg and mid-level lapse
rates approaching 8 C/km. This alone provides enough instability
to support robust updrafts capable of producing large hail. When
you factor kinematic parameters, the hail and tornado potential
increases even further...particularly late in the afternoon and
overnight when a robust shortwave trough and jet streak move over
the Southern Plains. The net result of this will be favorable
shear vectors for supercells and tornadoes.

Additional storms are expected to develop this evening to our west
as the more robust shortwave trough intersects the dryline. Very
strong forcing for ascent and favorable shear vectors will allow
for quick upscale growth, changing the convective mode to linear
in short-order. The line of storms is expected to move into our
western counties around midnight and move east through the early
morning hours. The main threat with this activity will be damaging
wind gusts and spin-up tornadoes along the leading edge of the
line of storms. While some stabilization will occur overnight,
strengthening low-level flow and a resurgence of moist advection
will preclude too much nocturnal stabilization...meaning the line
of storms will be more than sufficient to overcome any capping. Of
course, this will be harder the further east the storms travel, so
we do expect an eventual downward trend in storm intensity after
the storms move through and east of the I-35 corridor early Sunday
morning.

The severe threat is lower across our eastern row of counties
compared to those northwest of the Metroplex today and tonight.
The opposite is true Sunday. The line of storms will be able to
sustain through the night, with a broken cluster of storms ongoing
early Sunday morning for areas east of I-35. By this time, the
line should be mostly parallel to the deep-layer flow, resulting
in an increased risk of training storms and heavy rain. The Flood
Watch may need to be extended and expanded southeast, but we will
hold off on any configuration changes at this time.

As the cold pool lingers over our area Sunday, afternoon
destabilization will allow for a gradual uptick in storm intensity
across the eastern third of our forecast area. While the parameter
space is not as favorable as it will be today, there should be
sufficient shear and instability to produce large hail, damaging
wind gusts, and isolated tornadoes.

Bonnette

&&

.LONG TERM... /Issued 225 AM CDT Sat Apr 27 2024/
/Sunday Night Onward/

As the sun sets across North and Central Texas, a few lingering
storms may be ongoing across eastern areas, some of which could
be strong to severe. Given storms are likely going to be on the
downward trend, the severe weather potential should come to an end
by midnight, leaving behind precipitation free conditions for
much of our area.

The shortwave responsible for Sunday`s convection will quickly
skirt away from the region Sunday night. Another shortwave with a
similar path will be entering the Southern Plains Monday morning,
inducing surface cyclogenesis across the Texas Panhandle. Given
the moisture starved atmosphere in place and a stout capping
inversion, storms appear unlikely Monday afternoon.

With the southern branch of the jet stream across the Southern
Plains, subtle disturbances will make their way from west to east
Tuesday through the end of the work week. As each disturbance
moves overhead, there will be a potential for thunderstorms to
develop. There will be plenty of instability for storms to be
strong or severe, however, timing and location remain highly
uncertain at this time.

A cold front is expected to push through the region the latter
half of next week, with guidance ranging from as early as Thursday
night to Saturday morning. Increased rain chances will accompany
the front and the threat for severe storms may increase once
again.

The cold front will provide temporary relief from the 80 degree
temperatures we`ll experience much of the week. Behind the front,
expect highs in the 70s with lows in the 50s.

Hernandez

&&

.AVIATION... /NEW/
Update:

We added a TEMPO at the tail-end of the TAFs since we have high
confidence regarding an overnight line of storms moving through.
We are still not overly confident of TS impacts to the D10
terminals this afternoon, but significant impacts to the Bowie
cornerpost are likely from ~00Z onward. The remainder of the
discussion below remains valid at this time.

Bonnette

Previous Discussion:
/06Z TAFs/

MVFR stratus is engulfing all of North and Central Texas at this
time. Expect it to move over all TAF sites and linger for most of
the morning. Ceilings should start to improve in the mid-late
morning, eventually becoming VFR in the afternoon. Gusty south
flow is expected through the valid TAF period, with occasional
gusts over 35 kts possible mainly between 00-06Z.

The main concern will be the morning, afternoon, and overnight
thunderstorms. At this time, we`re expecting all of the morning
activity to remain well west of any TAF site. Storms should creep
east through the day, encroaching on the D10 terminals late in the
afternoon. There is still uncertainty if the storms will be close
enough for VCTS/TEMPO, or remain near SPS/Wichita Falls. We have
maintained VCTS in the current TAFs...but will have to monitor
real-time trends and updated guidance closely.

We are more confident of storms impacting the terminals some time
after 06Z tonight as a line of storms moves in from the west.
Since it`s still 24 hours away, we only have SHRA VCTS in the
TAF...but a prevailing thunder line will likely be needed sometime
between 07-12Z Sunday.

Bonnette

&&


.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    82  67  80  66  85 /  50  90  80   5   5
Waco                82  70  77  65  85 /  30  90  90  10  10
Paris               82  68  74  62  82 /  50  70  90  30  10
Denton              80  66  80  62  84 /  50  90  70   5   5
McKinney            81  66  77  64  83 /  50  90  90  10  10
Dallas              83  69  79  65  86 /  50  90  90  10   5
Terrell             82  69  75  64  83 /  40  90  90  30  10
Corsicana           85  70  76  67  85 /  30  50  90  30  10
Temple              82  69  77  66  86 /  30  70  90  10  10
Mineral Wells       80  64  82  60  87 /  50  90  30   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Sunday evening for TXZ091>095-100>107-
117>123-131>135-144>146-159.

Wind Advisory from noon today to midnight CDT tonight for
TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175.

Flood Watch from Sunday morning through Sunday evening for
TXZ147-148-160>162-174-175.

&&

$$