DFW FORECAST DISCUSSION
000
FXUS64 KFWD 230442
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1142 PM CDT Thu Aug 22 2019


.AVIATION...
/06Z TAFs/
Most of the afternoon convection west and northwest of North
Texas has dissipated with the loss of surface heating, but a few
showers and storms will linger in this same region overnight due
to the passage a weak shortwave trough. Any lingering storms
overnight/Friday morning will have no immediate impacts at the
Metroplex terminals, but may cause some deviations at the Bowie
cornerpost. Slightly better thunderstorm chances are expected
Friday afternoon with the arrival of a weak front. It is
difficult to say exactly where this boundary will end up since
convective outflows will alter its movement. For now we have
decided to keep the VCTS mentioned at the Metroplex terminals from
21Z to 01Z. Storms should stay well north of Waco, so no impacts
are anticipated.

Outside of the thunderstorms, VFR will prevail with scattered
daytime Cu and scattered to broken high clouds.

A south to southeast wind will continue at speeds at or below 12
knots.


79

&&


.SHORT TERM... /Issued 238 PM CDT Thu Aug 22 2019/
/This evening and tonight/

The upper-level ridge that has been plaguing our region with
excessive heat the past several days has retrograded towards the
Desert Southwest today. To be sure, it`s still plenty hot, but
temperatures are currently running in the low to mid 90s at most
locations, as opposed to the upper 90s by early afternoon.
Humidity levels are still elevated, resulting in heat indices in
the upper 90s to near 100 F, but they should stay below our Heat
Advisory criteria.

For this evening, some slight chance to chance PoPs were kept in
our northwestern counties and along the Red River. Visible
satellite has shown a bit of agitated cumulus in these areas. A
weak upper-level shortwave trough is making its way through the
Texas Panhandle, and perhaps this could provide just enough ascent
to get a few showers and thunderstorms going this evening.
Anything that develops this evening will be very isolated in
nature however, and the overwhelming majority of folks (even where
PoPs exist) will not see rainfall, and certainly nothing
appreciable. The main concerns if a thunderstorm gets going will
be cloud-to-ground lightning strikes and gusty winds. Given that
fuels are getting fairly dry out west (and we have seen some
respectable wildfires in Palo Pinto and Hardeman Counties during
the past week), any cloud-to-ground lightning strikes would bring
the risk of lightning fire starts, even as fire weather conditions
remain low (see the Fire Weather Forecast for more information).

More significantly, this shortwave trough should kick off more
widespread convection up in the Sooner State. Flow aloft is
relatively weak, which should keep the storms north of the Red
River. It is not impossible however that a few of these storms,
likely in a weakening state, could creep into our northern
fringes, so for that reason, low (20-30 percent) PoPs are
indicated during the overnight. Again, rainfall would be light to
non-existent in most locations, with a minimal severe weather
threat.

37

&&

.LONG TERM... /Issued 238 PM CDT Thu Aug 22 2019/
/Friday through Next Week/

Ridging aloft will gradually weaken during the first part of the
period as weak shortwave troughs move from west to east across
the Southern Plains. The first of these features will generate
scattered thunderstorms across Oklahoma during the day Friday. The
disturbance and its associated convection/outflow will help nudge
a front south of the Red River, which will likely be the focus of
isolated thunderstorms Friday afternoon and evening across parts
of North Texas. Slight chance to chance POPs will hence remain in
place across the northern half of the region on Friday, with the
better chances occurring along the Red River in the vicinity of
the front. That being said, mesoscale processes may actually
determine where the best rain chances occur, and we will need to
keep a close eye on the locations of any possible outflow
boundaries originating from the Oklahoma storms. For most of the
region, hot, muggy and rain free conditions will occur on Friday
with highs in the mid and upper 90s.

A second disturbance will translate the Southern Plains on
Saturday, bringing similar, if not slightly higher rain chances
to areas mainly along and north of the I-20 corridor. Slight
chance POPs, however, will extend southward through the entire
forecast area. Severe weather will be unlikely, but a few storms
will be capable of producing strong wind gusts each afternoon.

The ridge will attempt to rebound on Sunday as the second
disturbance exits to the east. This will be fairly short-lived,
however, as a larger-scale shortwave is progged to dive
southeastward out of Alberta Sunday and deepen over the Plains on
Monday. This system will push another cold front southward into
the area on Tuesday. Convection may accompany the front, but
coverage will likely remain isolated due to the ridge still
remaining somewhat present and the better forcing associated with
the shortwave remaining to our north.

Backing up into Monday, fire weather conditions may become a
concern as pre-frontal compressional heating will coexist with a
tightening pressure gradient. Hot and breezy weather will be the
outcome, and when taking into account the recent dry spell,
should result in an elevated fire threat generally along and west
of the Interstate 35 corridor. The Monday temperature forecast
will indicate triple digit highs for areas roughly along and south
of I-20 and along and west of I-35.

Mid range model data contains evidence of a deepening low over
the Hudson Bay mid to late next week, creating broad troughing
across the eastern third of the CONUS. This pattern would bring
another cold front southward through the region, perhaps leading
to below-normal temperatures just beyond a week from now.
However, the GFS is much more aggressive with the pattern shift
compared to the ECMWF, so we will keep expectations of any
significant relief from the summer heat tempered for now.

30

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    79  96  78  95  78 /  10  20  20  30  10
Waco                77  96  77  98  77 /   5  10  10  20  10
Paris               74  90  73  87  72 /  20  40  30  40  20
Denton              77  94  76  93  77 /  20  30  20  40  10
McKinney            77  94  76  92  76 /  20  20  20  30  10
Dallas              80  96  78  95  78 /  10  20  20  30  10
Terrell             77  96  77  94  77 /  10  10  20  20  10
Corsicana           76  96  75  96  75 /   5   5  10  20  10
Temple              75  97  75  97  76 /   5  10   5  20  10
Mineral Wells       76  96  74  95  74 /  10  20  20  30  10

&&

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

$$

79/24

NWS FWD Office Area Forecast Discussion