000
FXUS64 KFWD 272051
AFDFWD

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

...New Long Term...

.SHORT TERM... /Issued 1226 PM CDT Sat Apr 27 2024/

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... /NEW/
/Monday Onward/

A lull in the active weather will occur on Monday as the
multitude of upper level systems responsible for this weekend`s
thunderstorms shift to the east, and a weak ridge develops
overhead. Storm chances will return on Tuesday, however, as a
shortwave rounds the northern flank of the ridge. This will help
ignite thunderstorms along the dryline, which will be positioned
across the Big Country by Tuesday afternoon. These storms should
remain confined to the western half of the region, keeping the
severe weather potential largely west of the I-35 corridor. A
secondary batch of convection may also occur across the southeast
zones where an active seabreeze may infiltrate Tuesday afternoon.
The southeast storms will likely remain sub-severe, though a few
may produce gusty winds and heavy rain.

By Wednesday, a stronger shortwave will be dropping southeast
through the Rockies, weakening the ridge and generating another
round of dryline convection across the Big Country mid to late
afternoon. A warm and unstable environment along with 35+ knots
of effective shear will support more severe thunderstorm potential
as convection spreads east through the region Wednesday evening.
Storms will dissipate Wednesday night as instability wanes and a
capping inversion strengthens at the 850-700mb level.

A cold front will then approach on Thursday as the shortwave
trough traverses the Plains, providing another focus for showers
and storms along with the dryline Thursday afternoon and evening.
Widespread convection will be the result Thursday afternoon
through Thursday night, with activity pushing south of the region
along with the front on Friday.

A short reprieve in rain chances will occur Friday into Friday
evening before a shortwave embedded in the subtropical jet
generates another round of precipitation Friday night into next
Saturday. All of the forecast area should be in the cool sector
following the frontal passage, keeping any thunderstorms elevated
in nature and resulting from isentropic ascent. This should limit
the severe potential, but a strong storm or two would be capable
of producing hail. After a seasonably cool and damp (next)
weekend, a strengthening ridge aloft should lead to a warm-up and
a rain-free start to the following week.

30

&&

.AVIATION... /Issued 1226 PM CDT Sat Apr 27 2024/
/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    66  79  65  86  68 / 100  80   0   5   5
Waco                68  77  64  85  67 /  80 100  10   5  10
Paris               67  75  63  82  63 /  50 100  20   5   5
Denton              63  79  61  85  66 / 100  60   0   5   5
McKinney            66  77  63  83  66 /  90  90   5   5   5
Dallas              67  79  64  86  67 /  90  90   5   5   5
Terrell             68  77  64  83  65 /  60 100  10   5   5
Corsicana           71  79  66  85  68 /  40  80  20  10  10
Temple              68  79  65  85  68 /  70  80  10  10  10
Mineral Wells       62  83  59  86  65 /  90  30   0   5   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.

&&

$$