Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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FXUS64 KFWD 140917

Area Forecast Discussion
National Weather Service Fort Worth TX
417 AM CDT Mon Oct 14 2019

/Today and Tonight/

An upper trough approaching from the West Coast will bring a rapid
increase in deep layer moisture today with precipitable water
values exceeding 1.5 inches across nearly all of the forecast
area by afternoon. The combination of moisture and weak lift from
an impulse embedded in southwest flow aloft will result in light
showers from the Big Bend to Central Texas this morning. Large
scale lift and mid level destabilization will increase this
afternoon and tonight once the upper trough moves into the Desert
Southwest. Scattered to numerous showers and thunderstorms are
expected to develop with the best coverage of storms generally
east of the Interstate 35 corridor where moisture will be the
deepest. Although most zones will receive some measurable rainfall
this afternoon and tonight, rain amounts across the northwest
zones will likely be meager. The primary hazards associated with
any storm this afternoon or tonight will be from lightning and
locally heavy rainfall.

Extensive cloud cover today will offset the low level warm air
advection, keeping high temperatures in the mid 70s to the lower
80s. Temperatures will not cool much tonight due to a thick
blanket of clouds and continued warm air advection with lows
ranging from the middle 60s to the lower 70s.



/Tuesday Through the Upcoming Weekend/

The shortwave currently deepening over California will struggle to
keep pace with its parent trough, an Alberta Clipper that will
dive into the Northern Plains on Tuesday. As the mid-latitude
cyclone swings through the Great Lakes into the middle of the
week, the southern stream disturbance will separate from the polar
flow and be left to linger over the Lone Star State. Although
showers and thunderstorms will likely be ongoing at daybreak
Tuesday, particularly east of the I-35 corridor, the
aforementioned cutting-off process will quickly veer the flow
across North and Central Texas. This would force the convective
complex to move off to the east, introducing strongly veered
westerly low-level flow in advance of a cold front. Although it is
uncertain how quickly this would transpire, it appears this
scenario would limit the duration of the rain event and reduce
rainfall totals.

A plume of Pacific moisture will keep considerable cloud cover in
place on Tuesday while maintaining the potential for elevated
showers and storms. While this would seem to limit the
destabilization of the boundary layer, the unseasonably warm start
to the day should still allow temperatures to soar into the 80s
with rich moisture in place. If the daytime is largely free of
convection, and the surface layer can sufficiently recover, more
vigorous storms could accompany the cold front as it enters North
Texas near peak heating. CAMs are beginning to hint at the
potential for discrete cells Tuesday afternoon/evening along the
advancing boundary. Large-scale forcing for ascent beneath the
right entrance region of a stout subtropical jet could allow for a
few strong/severe storms. Large hail and damaging winds would be
the primary players. Despite the near-boundary mechanics at work,
the veered surface flow would tend to reduce the sub-cloud
helicity, and the tornadic potential would be low.

While the passage of the front Tuesday night will bring an end to
the rain event for much of North Texas, our disturbance will
remain upstream, maintaining a moisture fetch through South Texas.
Our Central Texas counties could see some lingering elevated
activity on Wednesday, not unlike the radar scope in the
postfrontal air this past Saturday morning, but the dry boundary
layer should limit the precipitation reaching the surface.
Guidance is struggling with the evolution of the shortwave, the
solutions developing a closed low obviously being the slowest. But
in any event, as the next upper trough approaches from the west,
the feature should be forced east of our meridian by Thursday
night. This next rainmaker will return rain chances just in time
for the upcoming weekend.



.AVIATION... /Issued 1140 PM CDT Sun Oct 13 2019/
/06Z TAFs/

Gulf moisture will be on the increase overnight and especially on
Monday ahead of a shortwave trough and a cold front. A stream of
Pacific moisture will add to the mix, which should increase
chances for showers and storms over the next 24 to 36 hours. Will
begin VCSH at 15Z Monday at KACT, and since models seem to be
having difficulty with the enhanced levels of Pacific moisture,
keep it going into Monday evening. Will begin VCSH at 21Z in the
DFW area, and include VCTS starting at 15/03Z as probabilities for
thunder become high enough to mention. A TEMPO group for thunder
may need to be added for overnight Monday night as we narrow down
the arrival of the main slug of moisture and subsequent chances
for convection. At this time, it appears that the better chances
for storms will remain north of KACT.

Another round of showers and storms along with a wind shift will
accompany a cold front on Tuesday, but this is well beyond the
current TAF cycle.



Dallas-Ft. Worth    79  70  87  55  71 /  30  50  60  40   5
Waco                79  70  88  57  72 /  40  40  60  60  10
Paris               76  65  79  50  66 /  10  80  80  50   0
Denton              81  69  86  53  71 /  20  40  50  30   5
McKinney            79  68  85  52  70 /  20  60  60  40   5
Dallas              80  70  87  56  71 /  30  50  60  40   5
Terrell             78  69  85  54  71 /  30  70  70  50   5
Corsicana           77  69  84  55  69 /  50  60  70  60  10
Temple              80  71  88  57  71 /  40  40  60  60  20
Mineral Wells       81  68  88  51  72 /  20  40  50  30   5




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