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

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FXUS64 KFWD 261719
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1219 PM CDT Thu Apr 26 2018


.AVIATION...
/18z TAFs/

VFR conditions are anticipated through the entire TAF period at
all sites, with a brief potential for showers overnight.

A very diffuse surface pressure pattern is in place overhead, with
a ridge axis oriented N-S roughly along the I-35 corridor. Winds
will be primarily out of the north this afternoon, but will
likely begin to veer this evening and eventually pick up an
easterly component ahead of a reinforcing cold front which will be
dropping through the Texas Panhandle/Rolling Plains. Wind speeds
should remain light enough (under 6-7 kts) for airports to hold
onto a north flow configuration before a more coherent northerly
flow re-establishes itself overnight. We`ll continue to advertise
a period of VCSH at all airports as a potent shortwave traverses
the region tonight/Friday morning. Cold mid-level temperatures
(-19 to -21 C) should allow for a sliver of instability to develop
overhead. Coupled with vigorous ascent from the incoming wave and
at least some modest mid-level moistening, some high-based showers
appear possible, even at Waco, although very dry low-levels may
lead to more in the way of virga. Instability appears too lacking
to result in any thunder potential, but this will continue to be
monitored this evening. Turbulence can be expected under
FL100-120.

Skies will quickly clear on Friday morning as this shortwave
departs, leaving SKC conditions behind.

Carlaw

&&


.UPDATE... /Issued 1123 AM CDT Thu Apr 26 2018/
The going forecast is in good shape. Just made some minor
adjustments to hourly trends and nudged high temperatures down
a smidge. Otherwise, sunny conditions will prevail overall all of
the region except for portions of Lamar County as moisture sloshes
around the periphery of a departing shortwave.

Carlaw

&&

.SHORT TERM... /Issued 314 AM CDT Thu Apr 26 2018/
/Today and Tonight/

Warmer conditions are anticipated today as abundant sunshine will
allow for more seasonable temperatures. Low rain chances will
return late tonight into early Thursday as a second compact upper
low dives southward through the Plains.

Pockets of very shallow fog will be possible this morning, but
the breezy winds aloft should keep visibility from falling too
far. We will monitor trends, however. Fog is most likely to occur in
sheltered/low-lying areas. Any fog that develops should dissipate
quickly after sunrise. Some lingering stratocumulus may graze
eastern parts of the Red River Valley, but it should be mostly
sunny with a few high clouds across most areas today. With large
scale subsidence in place behind the upper low that resulted in
Wednesday`s rain, tranquil conditions are expected through the
daytime hours.

The trough axis currently across the northern High Plains will
amplify and dive southward tonight. While low levels are moisture
starved courtesy of the recent frontal intrusion, mid and upper
levels will moisten and a deck of altocumulus will invade the area
tonight from the north. Lapse rates also steepen and given the
presence of decent lift, there will likely be some high-based
convection that initially forms over Oklahoma and moves southward
into North Texas. At this time, it`s unclear as to whether or not
enough instability aloft will be sufficient for thunderstorms. In
fact, it`s even possible that much of what develops may not
produce much in the way of measurable rainfall. For now I`ll
maintain a slight chance for showers and sprinkles in the forecast
given the uncertainty in the magnitude of instability. The best
chance for very light rain will be north of Palestine to Cleburne
to Graham line.



24

&&

.LONG TERM... /Issued 314 AM CDT Thu Apr 26 2018/
/Friday through Wednesday/

The end of the week and weekend are shaping up to be pretty nice
with near zero rain chances and seasonal temperatures. Friday
morning will start off with some passing cloud cover behind
another cold front, but skies will quickly clear and temperatures
will warm into the mid/upper 70s by afternoon. Mid level ridging
will dominate through the weekend, but by Saturday afternoon
southerly winds will become established and Gulf moisture will
begin a steady transition northward.

On Sunday a strong upper low will be over the western U.S. and
will slowly pivot eastward into Monday. As it does, a second
stronger shortwave will dig southward along the California coast
resulting in a generally large troughing pattern over most of the
western U.S. As this pattern amplifies through Tuesday, we`ll see
strong pressure falls in the lee of the Rockies which will help
strengthen southerly flow across North Texas and will accelerate
moisture return into the region. An eastward expansion of a deep
elevated mixed layer over much of Texas featuring steep lapse
rates and a stout capping inversion should occur by Monday
afternoon and continue through Wednesday. Given that the best
forcing for ascent will still be tied closer to the upper low over
the southwest U.S., we should see mostly precipitation free days
through Tuesday although we`ll likely have an increase in cloud
cover associated with the nocturnal low level jet and perhaps a
few showers beneath the strong cap. The dryline may become active
across parts of West Texas Monday and Tuesday, but given the
expected convective inhibition in place across North Texas, the
best chances for storms will be west of our forecast area.

By Wednesday, a strong shortwave is expected to eject into the
Plains and this may finally be sufficient for a better coverage of
thunderstorms across parts of North Texas. We`ll continue to
monitor this over the coming days, as these slower moving upper
lows can often take longer to eject eastward than currently
forecast. In addition, it appears that more favorable parameters
for severe weather will be in place across the region through next
week.

Dunn

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    73  55  77  52  81 /   0  20   0   0   0
Waco                75  50  79  50  82 /   0  10   0   0   0
Paris               69  51  73  48  77 /   0  20   0   0   0
Denton              73  50  76  47  79 /   0  20   0   0   0
McKinney            71  50  76  48  79 /   0  20   0   0   0
Dallas              74  56  78  54  81 /   0  20   0   0   0
Terrell             71  52  77  50  80 /   0  20   0   0   0
Corsicana           72  52  79  52  81 /   0  20   0   0   0
Temple              75  50  80  51  81 /   0  10   0   0   0
Mineral Wells       74  51  77  46  81 /   0  20   0   0   0

&&

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

$$



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