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

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FXUS64 KFWD 180811
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
311 AM CDT Sun Aug 18 2019


.SHORT TERM...
/Through Tonight/

Along the southern flank of a westerly upper-level jet, decaying
convection over Oklahoma has spread some mid/upper clouds and a
few remnant showers near the Red River early this morning. As this
convection continues to dissipate, cloud cover should gradually
thin across northern counties. Farther south, however, 30 kt of
925mb flow will transport low-level stratus north/northeastward
across the approximate southeastern half of the CWA this morning.
This cloud cover should dissipate by mid/late morning, though, as
diurnal mixing then promotes pockets of fair-weather cumulus this
afternoon.

This persistent and anomalously strong (by mid-August standards)
low-level jet has maintained a solid fetch of Gulf moisture,
yielding a mean mixing ratio of 13.8 g/kg on our 00Z sounding.
Therefore, similar to yesterday, diurnal mixing will help lower
surface dew points some, but not enough to avoid dangerous heat
indices. Expect another bout of heat index values around 105-110
this afternoon, as temps rise into the upper 90s to around 104.

Another round of convection is expected to develop this evening
into early tonight across northwest Texas and Oklahoma. Downstream
development, aided by the low-level jet, may bring some decaying
cells close to our Red River counties once again by late evening.
However, due to the late arrival and weak large-scale ascent,
opted to keep the forecast dry for the time being.

Picca

&&

.LONG TERM...
/Monday through Next Weekend/

Statistically, we may have come to the end of the hottest part of
the summer, but the reality of this season is that stifling heat
will continue for the next several days as a strong ridge
continues to dominate the mid and upper levels of the troposphere.
The ridge axis will actually shift northward across North Texas
on Monday, becoming centered over southern Oklahoma on Tuesday.
The only changes in the local weather will be a shift in the mid
level winds from west to east, while the Gulf/sea breeze will
likely push scattered afternoon convection farther inland. Even
so, POPs have been kept below 20 percent for the southeast zones,
with the expectation that showers or storms will rapidly dissipate
as they enter from the southeast.

The main story will continue to be dangerous heat, with high
temperatures reaching triple digits and heat indices soaring
above 105. In fact, several locations may see heat index readings
pushing 108 to 110 on Monday and possibly again on Tuesday. The
current plan is to extend the Heat Advisory into Monday and
reassess the data later today and tomorrow. Though heat indices
will come close in several spots, conditions should remain just
below excessive heat warning criteria.

The first half of this week should be the hotter half, as it looks
like some relief (albeit minor) could occur as weak disturbances
chip away at the intensity of the ridge late this week through
next weekend. The first impulse will be in the form of a weak
shortwave rolling southeast across eastern Oklahoma, bringing a
slight chance of storms to areas north of I-20 and east of I-35
Wednesday night and Thursday. A second disturbance takes a similar
path 24 hours later, bringing low rain chances to the same areas
Thursday night and Friday. It will still be hot, but hopefully
these features will help keep high temperatures below 100 for the
Thursday-Friday time frame. It looks like a broad weakness will
remain present in the ridge over the area next weekend, which may
bring temperatures back to near-normal values Saturday and next
Sunday.

30

&&


.AVIATION... /Issued 1135 PM CDT Sat Aug 17 2019/
/06z TAFs/

Convection across Northwest Texas and southwestern Oklahoma is
still ongoing as of 11pm, although this activity remains of
little consequence for the TAF sites tonight. Meanwhile,
respectable southeasterly flow prevails through the low levels,
which should allow for the development of low stratus across parts
of Central Texas prior to daybreak. At this time, am expecting
the greatest potential for cigs to remain SE of Waco, and will
show no more than a SCT deck between 1-2 kft for KACT. However,
some brief cigs may need to be introduced depending on overnight
trends. Otherwise, VFR will prevail through the period. Winds will
generally be 10-15 kts out of the SSE with some higher gusts
around 20 kts Sunday afternoon. Additional convection is expected
across southern Oklahoma Sunday afternoon and evening, but should
not directly impact the TAF sites.

-Stalley

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth   101  81 101  81 100 /   0   0   0   0   0
Waco               102  79 102  79 100 /   0   0   0   0   0
Paris               98  77  98  77  97 /   0  10   5   0   5
Denton             101  79 101  80 100 /   0   5   0   0   0
McKinney           100  79 101  79 100 /   0   5   0   0   0
Dallas             101  81 102  82 101 /   0   0   0   0   0
Terrell            100  78 103  80 102 /   0   0   0   0   5
Corsicana          101  78  99  77  97 /   0   0   0   0   0
Temple             102  78 100  77  98 /   0   0   0   5   0
Mineral Wells      103  76 101  77 100 /   0   0   0   5   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Monday for TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.

&&

$$

11/30


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