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Area forecast discussion
National Weather Service Fort Worth Texas
241 PM CDT Mon Oct 14 2019

Long term...
/Wednesday Onward/

Synopsis: the second half of the week and the first half of the
weekend will feature relatively quiet weather, and a steady
warming trend. Another storm system looks to develop over The
Rockies late in the weekend, bringing another cold front as well
as rain/storm chances to north/central Texas by Sunday and next

The extended portion of the forecast will pick up in the wake of
Tuesday night's cold front passage. Wednesday will feature below
normal temperatures with highs ranging from the upper 60s (south)
to near 70 (north). Temperatures will likely be a little cooler in
the south as there may be some lingering showers, and certainly
some lingering cloud cover there for the first half of the day. By
Wednesday night, calm winds, clear skies, and dewpoints in the
low 40s should allow for excellent radiational cooling. Lows will
fall into the 40s across virtually all of our forecast area.

A steady warming trend will commence Thursday and into the weekend
as ridging aloft builds over the central Continental U.S.. a weak shortwave
trough will slide south of the ridge through the Rio Grande
Valley, but any ascent associated with this trough will likely
remain to our south. This will keep rain chances across The Hill
Country and into the lower Rio Grande, and away from our forecast

The next storm system will begin to develop late this weekend over
the Rocky Mountains. While the models vary on the details, the
deterministic ECMWF, GFS, and their ensembles, are in good
agreement of deep anomalous troughing over the western Continental U.S. On
Saturday and into Sunday. As the trough axis digs into the Rocky
Mountains late Saturday, differential cyclonic vorticity advection
and strong upper-level divergence near the exit region of a 100+
knot jet streak at 250 hpa will result in Lee cyclogenesis. As
this low deepens, strong warm air advection will allow
temperatures to rise well above normal for Sunday. A surface cold
front is likely to push through late Sunday or Monday as the
surface low lifts northeast into the Great Lakes region.
Precipitation appears likely ahead of this cold front, but at 6-7
days out, it's a little early to get too far out into the weeds
with regards to severe weather or heavy rain potential. The bottom
line right now is that with US now deep into autumn, the weather
pattern looks to remain active for the foreseeable future.



Short term... /issued 220 PM CDT Mon Oct 14 2019/
/this afternoon through Tuesday/

We continue to monitor a surface warm front near the Colorado
valley and far southwest County Warning Area as it is expected to lift northward
late today and this evening across the area. This process will be
supported by increasing mid level energy arriving from the
southern stream of the westerlies from Mexico, as it carries mid-
upper level moisture from a previous weak tropical low that was
near the Baja Peninsula of northwest Mexico this time yesterday.
Meanwhile, increasing southerly flow to between 20-30 knots will
draw rich Gulf moisture northward this evening with scattered to
numerous showers and a few embedded thunderstorms expected by mid
evening. This activity will continue through midnight; or into
the early pre-dawn hours Tuesday along and either side of the
I-20/30 corridors as this will be where ascent will be maximized.
In addition, better Theta-east advection will be focused across this
area while lesser rain chances tonight are expected across central
Texas -- more displaced from the surface warm front and better
mid level forcing.

Neither flooding or severe weather are expected, but lightning
strikes and the resulting cracks of thunder may be enough to wake
you up. Despite increasing south- southeast surface winds later
today into this evening, plentiful cloudiness will keep highs in
check with many areas remaining in the mid- upper 70s. Some
locations west of US 281 could reach the low 80s where a thinner
cloud layer and earlier warm front passage will exist and occur

During the pre-dawn hours subsidence behind the departing
subtropical branch mid level impulse should help most areas
remain dry though there may be some lingering showers across the
northeast counties. Strong mixing and southerly winds 10-15 mph by
late morning and beyond Tuesday should set up a very warm and
breezy mid October day for the area. Areas along and west of I-35
will see highs from the mid 80s to around 90 degrees along and west
of US 281 as we experience veering low level flow just in advance
of an approaching strong surface cold front. The cold front looks
to enter the Red River valley by late afternoon, as it's
supported by a more vigorous mid level impulse diving southeast
from the northern stream of the westerlies across far West Texas
and New Mexico Tuesday afternoon. This is further west than
previous forecast model runs and cams noted in previous days.
Still, there will be enough juxtaposition of forcing from this
impulse and convergence just in advance of the cold front for the
development of scattered to numerous thunderstorms in advance of
the cold front; especially east of I-35, where the veered low
level wind fields will focus the better low level Theta-east

The very warm temperatures in the 80s will combine with rich Gulf
moisture transporting northward for instability values reaching
1500-2000 j/kg in advance and along the cold front. Finally, I
believe the marginal risk east of I-35 and north of I-20 looks
well-warranted with northwesterly deep layer shear values between
35-45 knots and effective wind bulk wind differences on the order
of 50 knots plus. Honestly, I wouldn't be surprised with the
slightly slower cold front arrival if there isn't an expansion of
this area southwestward with a possible slight risk introduced
across The Ark-la-tex back into southeast Oklahoma and possibly
our far northeast counties if these parameters continue to hold up
the next 24-30 hours.



Aviation... /issued 220 PM CDT Mon Oct 14 2019/
/18z tafs/

Concerns and challenges: several. Timing of warm frontal passage
and low cig challenges this afternoon at Waco, then first elevated
round of rain showers/ts later this evening and the return of MVFR cigs by
03z and after(possible brief IFR at kact tonight). Finally,
lifting/scattering of cigs to VFR by late morning Tuesday, then
timing cold frontal passage and brief westerly Crosswinds just in advance of
the frontal passage. Also, increasing ts chances after 21z at dfw
international in the 24-30 hour forecast.

A warm front currently near the Colorado River valley SW of all
airports will continue to lift northward just in advance of a
southern stream, mid level impulse that arrives across the area
later this evening. With warming temperatures in behind the
surface warm front, cigs at all airports should be VFR with a few
hit n' miss showers. VFR cigs later today at all airports
should slowly come down as MVFR cigs(possibly IFR at waco) form on
increasing S/SW 25-30 knot flow at 925 mph with low level moisture
increasing off the Gulf of Mexico.

The strong lift from this first mid level impulse will result in
increasing rain showers across all airports with the potential for
embedded ts at dfw airports where the strongest upward vertical
motions will coincide with some instability just behind the warm
front. I did include a 2-3 hour thunderstorms in the vicinity period at all dfw Metro
airports with this in mind, as winds continue to veer more S-southeast at
6-9 knots. The strongest lift should remain displaced far enough
north from Waco Regional Airport that I only kept vcsh for this
evening. There will likely be a lull in convective activity at all
airports in the 06z-18z/21z time frame Tuesday, as we experience
brief subsidence across the area. Cigs should rise or scatter into
VFR after 15z tues with S winds around 10 knots, veering west-southwest/SW
just ahead of the surface cold front arriving into the dfw Metro
area by 00z Wednesday. Frontal passage is likely to occur beyond the 24-30
hour forecast for dfw international Airport, as a northern stream
mid level impulse dives southeast across the Southern Plains/Ozarks
region. This system will work with forcing along the approaching
cold front that I have introduced a veering of winds to the west-southwest
with thunderstorms in the vicinity 21z Tuesday and beyond.



Preliminary point temps/pops...
Dallas-ft. Worth 69 87 54 70 49 / 50 60 40 5 5
Waco 70 89 57 70 49 / 30 60 60 10 5
Paris 64 80 49 65 44 / 70 80 50 0 5
Denton 68 88 52 70 46 / 50 60 30 0 5
McKinney 68 86 51 69 46 / 60 70 40 0 5
Dallas 70 87 55 70 49 / 50 60 50 5 5
Terrell 68 86 54 70 47 / 70 70 60 5 5
Corsicana 69 85 55 68 48 / 50 60 60 10 5
Temple 70 88 57 69 50 / 20 60 60 20 5
Mineral Wells 67 89 50 71 44 / 30 50 30 0 5


Forward watches/warnings/advisories...

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