602
FXUS64 KFWD 271726
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1226 PM CDT Sat Apr 27 2024

...New Aviation, Short Term...

.SHORT TERM... /NEW/

Mesoscale Update:

A warm and humid airmass is in place across North and Central
Texas this afternoon with temperatures creeping up toward 80
degrees and dewpoints in the lower 70s. A dryline is still well
west across West Texas where scattered severe thunderstorms have
developed through the morning. Farther east, a few convective
attempts have been noted across northwest Texas where the
atmosphere has become strongly unstable and very weakly capped.
Thunderstorms will likely increase in coverage in this area
through the mid afternoon hours.

In our area, latest RAP objective analysis indicates MLCAPE
greater than 3000 J/kg at this time with some capping remaining.
An aircraft sounding from 11:30 am indicated a deep moist boundary
layer with around 70 J/kg of MLCIN remaining. This may be
sufficient to keep convection at a minimum across North Texas
through the afternoon. Mesoscale domain visible satellite imagery
show a generally unimpressive CU field across the region at this
time. For now, we`ll keep PoPs generally around 20% through the
afternoon.

Later tonight, strong forcing for ascent will overspread the
region and a well developed squall line is likely to move through
North Texas. Favorable low and mid level wind fields along with
ample instability will support a significant severe weather threat
through the overnight hours. Initial storms will pose a threat for
large hail, damaging winds, and perhaps a few strong tornadoes
mainly across our northwest counties, while we`ll transition into
more of a damaging wind threat overnight along with some embedded
QLCS tornadoes.

There will also continue to be a threat for flash flooding through
the overnight period and into Sunday.

Further relevant details from this morning`s discussion have been
retained below...

Dunn

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:

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/
/18Z TAFs/

Cigs have lifted through the morning and have generally become VFR
around 3500 ft early this afternoon with VFR expected to prevail
through much of the afternoon and early evening. We`ll monitor for
potential thunderstorm development within the D10 airspace this
afternoon/evening but right now it looks like most of the activity
will remain off to the northwest into the evening.

MVFR cigs are expected late this evening ahead of an approaching
line of severe thunderstorms which will move across North Texas
overnight. Timing is fairly consistent among the guidance and will
include a VCTS by 7Z with a TEMPO for +TSRA from 9-11Z. This line
will likely be severe and include a threat for damaging winds,
hail, and a few tornadoes. This line of storms will move east
early Sunday morning and we`ll have to see what impact it has on
additional storm development Sunday afternoon.

Dunn

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    82  66  79  65  85 /  20 100  80   0   5
Waco                82  68  77  64  85 /  10  80 100  10  10
Paris               82  67  75  63  82 /  10  50 100  20  10
Denton              80  63  79  61  84 /  30 100  60   0   5
McKinney            81  66  77  63  83 /  10  90  90   5  10
Dallas              83  67  79  64  86 /  20  90  90   5   5
Terrell             82  68  77  64  83 /  10  60 100  10  10
Corsicana           85  71  79  66  85 /  10  40  80  20  10
Temple              82  68  79  65  86 /  10  70  80  10  10
Mineral Wells       80  62  83  59  87 /  40  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 until 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.

&&

$$