000
FXUS64 KFWD 210554 AAB
AFDFWD

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1154 PM CST Tue Nov 20 2018

.AVIATION...
/06Z TAFs/

Continued VFR with a gradual return to south flow.

Lift downstream of an approaching shortwave will rapidly moisten
the mid levels above South Texas on Wednesday. Some of the
associated mid cloud will clutter the Metroplex skies late in the
day, but the more persistent VFR ceilings will be across Central
Texas. With considerable dry air beneath these cloud bases, any
precipitation will struggle to reach the surface. Even for Waco,
where the cloud bases will fall below FL100 and the depth of this
elevated moisture will be considerably thicker, the greater
potential for light rain will remain to the south and southeast.
Virga in vicinity of all TAF sites may result in some sub-cloud
turbulence.

The surface high that has dominated the Southern Plains will very
slowly shift to the east, and only tepid southeasterly flow will
return to the Metroplex on Wednesday. The southeast winds may not
reach Waco until Wednesday evening. Regardless of the direction,
the wind speeds should remain light enough to maintain south flow
operations.

25

&&

.SHORT TERM... /Issued 336 PM CST Tue Nov 20 2018/
/Tonight thru Wednesday/

Tranquil weather is expected tonight. Surface high pressure will
remain centered to our northeast and light northeast winds will
prevail through the night. Under clear skies, overnight lows will
fall into the 30s.

As the surface high slides to the east tomorrow, the winds will
gradually come around to the south and southeast across most of
the region. A shortwave will slide across the region, drawing
limited moisture north and providing some lift. Forecast soundings
indicate the lower levels of the atmosphere will remain dry, thus
preventing much precipitation from reaching the ground, but some
elevated showers will be possible south of Interstate 20 in the
afternoon and evening hours. Very limited instability will likely
prevent thunderstorms but could support shower development.

High and mid level clouds will be on the increase during the
afternoon hours on Wednesday, and high temperatures are expected
to reach the mid 50s to around 60 degrees.

JLDunn

&&

.LONG TERM... /Issued 336 PM CST Tue Nov 20 2018/
/Wednesday night through next Tuesday/

We`ll hold on to some low PoPs through Wednesday evening south of
I-20 as the core of a vigorous shortwave disturbance passes
overhead. While some of our extended hi-resolution guidance
continues to advertise some light rainfall as far north as the
Red River, forecast soundings reveal extremely dry air in place
between 5 and 15 kft. Given a lack of both additional elevated
instability and low-level moisture, measurable precipitation
appears unlikely across North Texas, but I have added a mention
of sprinkles through the evening hours. We`ll clear out quickly
after midnight and surface winds will drop off to under 5 mph
leading to good radiational cooling potential, even if this
process is held up a bit by the evening cloud cover. The NAM,
which cools the near-surface the most aggressively of the
available guidance, indicates some potential for patchy fog
development by daybreak Thursday, but this potential appears too
low to warrant an introduction into the worded forecast at this
juncture.

Cirrus will progressively muddy-up the sky on Thanksgiving Day as
the next jet streak opens the gate to high-level Pacific moisture,
but no precipitation is expected. High temperatures will be a tad
under climatological normals in the low to mid 60s, but overall,
Thursday looks like a pleasant day weather-wise.

By Thursday evening, a 130+ kt jet streak will emerge across the
Texas/Oklahoma panhandles. This will facilitate the next round of
lee cyclogenesis in the favored left exit region across western
Kansas Thursday night. While the associated mid-level shortwave
impulse will be robust, with notable 100+ m/12 hour 500 mb height
falls spreading across North Texas on Friday afternoon, moisture
still appears to be the missing ingredient. 925-850 mb flow will
become progressively more southwesterly on Friday and surface
winds will stay generally easterly, greatly limiting the potential
for an influx of higher theta-e air off the Gulf. That said,
moisture should be in somewhat better supply than Wednesday`s
system, and vigorous forcing for ascent warrants carrying 20-40%
PoPs near the I-35 corridor, increasing to 50-60% across our far
east/northeastern counties Friday morning/early afternoon. I`ve
held off on a mention of thunder across our eastern counties given
what appears to be pretty robust capping (even in the face of
strong height falls), and limited instability, but we`ll continue
to monitor this potential.

Our parade of potent PV-anomalies will continue on Saturday and
into Sunday as another surface cyclone materializes to our
northwest. The tightening pressure gradient will result in
southwesterly breezes increasing Saturday afternoon into the 15-20
mph range. While we`ll likely receive an influx of additional
high-level cloud cover, the breezy surface winds should allow
temperatures to soar into the 70s (perhaps even upper 70s to near
80 across our westernmost counties). With the passage of Friday`s
pacific front, moisture appears too limited for this next system
to squeeze out any precipitation from a sub 0.5" PWAT airmass.

Sunday will be a windy and much cooler day featuring high
temperatures in the 50s to near 60 degrees. Near dry-adiabatic
lapse rates up to 800 mb will support some mixing of 40-45 kt
flow to the surface in the form of wind gusts of 35 to 40 mph.
This will place us close to Wind Advisory criteria on Sunday.
While the copious rainfall over the last two months has done
wonders for our drought conditions, the recent widespread freezes
have helped cure grasses/fine fuels across the region. As a
result, there will be elevated concerns for initial attack fires
this weekend as gusty winds and low relative humidity spread
across the area, most notably along and west of I-35 both on
Saturday and Sunday.

Quiescent and cool weather is expected through the early portions
of next week.

Carlaw

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    38  59  40  61  50 /   0  10  10   0  10
Waco                35  59  40  61  50 /   0  30  20   0   5
Paris               33  58  37  59  45 /   0   0   5   0  10
Denton              33  57  37  61  50 /   0  10   5   0  10
McKinney            35  57  38  59  49 /   0  10   5   0  10
Dallas              39  60  41  61  52 /   0  10  10   0  10
Terrell             36  59  39  61  50 /   0  10  10   0  10
Corsicana           38  58  41  59  50 /   0  20  20   0   5
Temple              35  59  41  61  50 /   0  30  20   5   5
Mineral Wells       33  58  38  61  49 /   0  10   5   0  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

25/30

NWS FWD Office Area Forecast Discussion