031
FXUS64 KFWD 160830
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
330 AM CDT Thu May 16 2024

...New Long Term...

.SHORT TERM... /Issued 134 AM CDT Thu May 16 2024/
/Through Friday/

With this update, the Flood Watch has been expanded northwestward
to include the DFW area and additional locations to the south and
west. While the heaviest rainfall is still expected in Central
Texas with today`s event, isolated totals in the 3-4" range will
be possible near or even just north of the I-20 corridor, too.
This flooding risk will unfold within an episode of strong to
severe convection, with the greatest severe risk also across
Central Texas.

Modest ascent acting upon steep lapse rates has allowed fairly
widespread high-based shower and thunderstorm activity to develop
from Wichita Falls to Houston as of 1 AM, and this sub-severe
activity is likely to continue through the morning while
eventually moving off to the northeast. Outside of some small hail
and brief heavy rainfall, this activity will be rather
inconsequential compared to convection later this morning.

The primary round of convection will get underway around or just
after daybreak and will initially occur north and west of the CWA
along a slow-moving frontal zone associated with a deepening
surface low situated near El Paso. As intense poleward moisture
flux occurs within a strengthening low-level jet, quick
destabilization will occur as low-level moisture advection beneath
steep lapse rates results in MUCAPE values of 2000-4000 J/kg.
PWAT values will increase from 0.75-1" to 1.5-2" in the next
several hours, and as this moisture arrives, rapid development of
convection will ensue between 7 and 10 AM as it collides with
multiple sources of lift. A steady ESE progression, likely to be
accelerated by cold pooling, will send one or more convective
clusters and/or line segments through North and Central Texas by
late morning and early afternoon. This activity will be capable of
very heavy rainfall with rates perhaps near 2" per hour, as well
as large hail and damaging wind threats, the primary of which will
be dependent on eventual convective mode. The heaviest rainfall
totals and greatest flood threat are still expected in Central
Texas where isolated amounts near 5" are possible.

The aforementioned slow-moving frontal boundary (or effective
frontal boundary modified by convective outflow) will also sag
south of I-20 towards midday. Depending on the extent of
convective activity during this time window, there could be a
threat for new redevelopment along this feature which would
likely be supercellular in nature. Backed easterly winds in the
vicinity of this surface boundary and attendant increased helicity
could result in an increased tornado threat across the southern
fringes of our forecast area along a corridor from Lampasas to
Temple/Killeen to Hearne. However, this will be very much
mesoscale driven, and a scenario involving faster-than-expected
upscale growth would act to minimize this threat in short order.
Eventual upscale growth into a large convective complex is
expected by late afternoon, with this main round of thunderstorm
activity shifting southeast out of the forecast area this
evening. However, lingering shower and isolated thunderstorm
activity is possible back to the north and west as additional
ascent continues to act upon steep lapse rates in areas that may
not have been entirely worked over by convection earlier in the
day.

A relative lull in convective activity is expected overnight,
although we cannot rule out additional light rainfall, while
widespread low stratus engulfs most of the forecast area heading
into Friday morning. Since the upper trough axis will still be
upstream tomorrow, additional isolated showers and thunderstorms
could redevelop during the daylight hours as the trough passes
overhead, but this convection is unlikely to be strong, and rain
rates should be unable to cause any further flooding issues even
after widespread rainfall today.

-Stalley

&&

.LONG TERM... /NEW/
/This Weekend Through Next Week/

Rain chances will come to an end across East Texas early Saturday
morning as our storm system finally pushes off to the east.
Ridging aloft will take its place, with positive mid-level height
anomalies prevailing into the upcoming workweek assuring above
normal temperatures. A shortwave will transit the Plains late in
the weekend, dampening the flow, but it will neither reintroduce
rain chances nor inhibit the warming trend. By Monday, nearly
every location will see afternoon highs in the 90s. The subsequent
(more potent) disturbance will take a more southerly track, which
may guide a late-season cold front and associated rain chances
into our area. While this could shave a few degrees off daytime
temperatures, the current forecast will maintain above normal
highs regionwide for day 7 (Wednesday, May 22).

25

&&

.CLIMATE...

Year-to-date precipitation totals (through May 16) have fallen to
9th wettest for DFW and 10th wettest for Waco, but both sites may
make up some ground later today.

&&

.AVIATION... /Issued 134 AM CDT Thu May 16 2024/
/06z TAFs/

Scattered high-based convection rooted near 10 kft will affect
most TAF sites for the next few hours before departing to the
east prior to daybreak. Afterwards, much more widespread and
stronger convection will develop upstream, arriving at the TAF
sites in the neighborhood of ~16z. A few hours of convective
impacts are likely through mid afternoon before storms eventually
shift southeastward. Following the departure of convection,
MVFR/IFR cigs are expected to fill in within northeasterly surface
flow although the timing of these cigs and when category
degradations will occur remains very uncertain. Additional
isolated shower and thunderstorm activity is possible overnight
into Friday morning although the potential is currently too low
to advertise in the TAFs.

-Stalley

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    77  67  82  67  91 /  80  50  20  10   5
Waco                73  66  82  65  88 / 100  40  20  10   5
Paris               80  64  80  63  87 /  50  50  40  20   5
Denton              75  63  80  63  89 /  70  50  20  10   0
McKinney            77  65  80  64  88 /  70  50  20  10   5
Dallas              77  66  84  67  91 /  80  50  20  10   5
Terrell             77  65  81  65  87 /  80  50  20  10   5
Corsicana           78  67  83  67  89 / 100  50  20  10   5
Temple              75  67  83  65  89 / 100  40  20  10   5
Mineral Wells       72  63  81  63  91 /  90  50  20  10   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 7 AM CDT this morning through Friday morning
for TXZ101>104-116>122-130>135-141>148-156>162-174-175.

&&

$$