000
FXUS64 KFWD 120119
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
819 PM CDT Tue Aug 11 2020

.SHORT TERM... /NEW/
/Through Wednesday Night/

North and Central Texas will remain on the eastern periphery of an
upper ridge, its subsidence still the primary factor in our
forecast. However, a potent shortwave swinging out of Oklahoma and
into the Ark-La-Tex has lit up the radar with showers and
thunderstorms. Some of this activity will impact Texoma into
Northeast Texas where the strongest cells will be capable of gusty
winds and small hail this evening. Restrained by a Bermuda high
retrograding into the Southeast, the upper trough responsible for
the convection will be slow to move east, eventually getting stuck
in the Mid-Mississippi Valley. Its slow progress will keep some
low rain chances in Northeast Texas into the daylight hours
Wednesday. However, by peak heating, the activity should be east
of our CWA.

Otherwise, August heat will prevail. Steady southerly flow will
replenish boundary layer moisture overnight, with 70+ dew points
throughout nearly all of North and Central Texas at daybreak
Wednesday morning. With the ridge`s influence more potent to the
west, high temperatures will range from the 90s in East Texas to
the triple digits along the I-35 corridor westward. With the
richer moisture to the east, heat index values may be rather
uniform, likely exceeding 105 throughout much of the region
Wednesday afternoon. Although a heat advisory may otherwise be
warranted, subsequent days may fail to reach criteria.

25

&&

.LONG TERM... /Issued 320 PM CDT Tue Aug 11 2020/

/Thursday through next Tuesday/

Hot and mostly rain-free conditions are expected through a
majority of the extended forecast period. Daytime high
temperatures will climb into the 103 to 105 degree range, with
heat index values approaching/exceeding 105 degrees. The hot and
relatively dry air mass west of I-35 will contribute to an
elevated fire weather threat through the end of the week. For more
information on that, please see the fire weather section appended
below. Into early next week, there may be an opportunity for some
relief from the heat.

The synoptic level flow through the end of the work week will be
characterized by anti-cyclonic flow atop an H594 ridge parked
across central New Mexico. In response to the modest flow aloft,
low-level cyclogenesis is progged by most guidance to occur across
western Oklahoma. This will veer the low level wind field,
particularly across the Big Country through the end of the week.
This should advect slightly "drier" air and encourage deeper
mixing leading to high temperatures in the 101-103 range. It`s
quite possible that a heat advisory may be needed for our Big
Country and west Central Texas counties in the future (Thursday
and Friday), but the current areal coverage of 103 degree heat or
greater is a bit too sparse for one starting Wednesday.

Farther east, the magnitude of low level mixing will be less and
thus dew points (upper 60s to near 70) combined with afternoon
temperatures near 100 degrees will equate to heat index values
near or just greater than 105 degrees through the weekend.
Similarly, we may need a heat advisory to address these higher
heat index values for Thursday. There is a non-zero risk for
showers and an isolated storm to drift southward out of the Red
River. With the ridge expected to provide enough of a subsident
regime, even on its eastern periphery, I`ll only advertise a 5 PoP
across East Texas for Thursday.

There could be some relief from the heat in the far reaches of the
extended forecast as the aformentioned mid-level ridge migrates
toward the west. Increasing troughing across the Central Plains
should send a frontal boundary southward. At present time, I`ll
advertise modest rain chances (near 30%) along the Red River and
across East Texas late Sunday into Monday. The airmass behind the
front does not appear too terribly colder, but highs on Monday and
Tuesday should remain out of the triple digits and close to 90
degrees.

Bain

&&

.AVIATION... /NEW/
/00Z TAFs/

VFR will prevail with south flow. Thunderstorms will disrupt
traffic inbound through the Bonham cornerpost, particularly during
the evening hours. Additional activity Wednesday morning may
impact early departures to the east.

25

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    81 100  81 100  81 /   5   0   0   0   0
Waco                80 101  78 101  78 /   5   0   0   0   0
Paris               73  95  74  98  76 /  40  20  10   5   5
Denton              79 100  79 100  80 /   5   0   0   0   0
McKinney            79  99  79 100  79 /  10   5   0   0   0
Dallas              82 100  81 101  82 /   5   0   0   0   0
Terrell             79  99  77 100  78 /  10   5   0   0   0
Corsicana           79  99  78  99  78 /   5   0   0   0   0
Temple              78 101  77 101  76 /   5   0   0   0   0
Mineral Wells       78 101  78 102  77 /   5   0   0   0   0

&&

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

$$

25/12