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

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FXUS64 KFWD 240920
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
420 AM CDT SUN JUL 24 2016

.DISCUSSION...
As is often the case in the summer, weak, subtle forcing
mechanisms are going to play a significant role in generating
clouds and precipitation - and modulating temperatures - over
North Central Texas during the next several days. Exactly WHICH features
trigger thunderstorms WHERE and WHEN remains problematic, and as
a result confidence in the overall precipitation forecast is NOT
great at the present time.

Our long-lived upper level ridge - stretching from OK to Southern
CA - will provide one more day of hot temperatures across North
and Central Texas. Starting Monday and continuing on through most
of next week, our region will be influenced by multiple weak
shortwaves, and by a persistent weakness in the mid-level flow
pattern. The net result will be cooler daytime highs and a chance
of rain over much of the area. Unfortunately, while we could see
some isolated higher amounts Monday, I`d caution everybody not to
get too giddy over the prospect of a widespread heavy rain event
this week.

For today, as mentioned, subsidence associated with the lingering
upper ridge will once again facilitate afternoon temperatures
between 98 and 102 degrees. Coupled with dewpoints in the upper
60s and lower 70s, areas from Sherman, Dallas and Corsicana
eastward will see heat indices climb into the 105-108 range.
Seriously considered issuing a Heat Advisory for this afternoon.
However, given the fact this is the last day we`ll see indices
this high for a while, coupled with the brief period above
criteria, decided to forego an issuance. We still need to stress
the importance of heat illness prevention across all of North
Central Texas, however. Otherwise, have continued with a small PoP
this afternoon in our eastern counties, where another round of
spotty showers and thunderstorms may occur after 4 pm today.

More substantial changes occur on Monday, as the weak upper level
vorticity center currently south of Memphis slides westward to
near Tyler. Moisture levels really increase from west to east
Monday afternoon, with PW values exceeding 2 inches east of I-35.
The combination of subtle yet effective lift provided by the
shortwave, coupled with copius moisture and instability should
yield at least scattered showers and thunderstorms by late Monday
afternoon - particularly east of Interstate 35. Was tempted to go
significantly higher than MOS guidance on PoPs Monday, given the
degree of moisture and instability, but the lack of any organized
surface forcing may preclude the more widespread activity being
implied by the GFS and ECMWF. As noted in previous discussions,
the high PWs and weak steering winds may lead to some localized
flash flooding with any strong cells that do form Monday.

The models clearly peg Monday as the relatively "big" day for
precipitation chances, due to the arrival of the first shortwave
from the east. However, both the ECMWF and GFS advertise a second
wave moving into Texas from the Lower Mississippi Valley Tuesday
and/or Wednesday. At the very least, our region will remain under
the influence of an inverted trough during the mid week, and this
would bode well for continued scattered thunderstorm chances,
particularly across our Central Texas counties. Held onto small
PoPs from I-20 northward both days, but areas from Lampasas to
Palestine will enjoy the best shot at rainfall Tuesday/Wednesday.

The picture really starts to get fuzzy from Thursday into the
weekend. While some weakness persists across North Central Texas
through Friday, the upper ridge to our west will begin to rebuild
eastward, while a pronounced shortwave drops through the Central
Plains. By comparison with earlier in the week, our overall rain
chances will diminish from Thursday onward through Sunday.
However, with our Red River counties remaining on the southern
fringe of a northwesterly flow regime over the Central U.S., we`ll
need to hang onto small PoPs in these areas into the weekend.

Clouds and scattered thunderstorms will temper our daytime highs
through Wednesday. However, as our PoPs fade and subsidence re-
asserts itself over the area, afternoon readings will climb back
to season norms by next Friday-Saturday.

Bradshaw

&&

.AVIATION...
/ISSUED 1131 PM CDT SAT JUL 23 2016/
VFR conditions are expected to prevail at the TAF sites through
12z Monday.

The scattered showers and thunderstorms that developed Saturday
moved to just east of a KDUA-KTYR line during the late afternoon
and evening hours before dissipating. Isolated to scattered
showers and thunderstorms are expected to develop again Sunday and
may move into areas east of a KGYI-KCRS-KLHB line from mid
afternoon /21z/ through sunset /02z Monday/. This activity may
affect the eastern arrival/departure gates but is not expected to
directly affect the TAF sites.

Winds of 5 to 10 knots will be generally southerly (varying
between southeast and south southwest). Expect some afternoon
cumulus and there may also be some cirrus debris from
thunderstorms to the east late afternoon into the evening hours.

58


&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth   101  81  96  79  95 /  10  10  40  30  30
Waco               101  78  96  76  93 /  10  10  40  20  40
Paris               99  76  93  75  94 /  20  20  50  30  30
Denton             100  78  95  75  94 /  10  10  40  30  30
McKinney            99  78  94  76  93 /  10  10  40  30  30
Dallas             101  80  95  79  94 /  10  10  40  30  30
Terrell             98  77  93  76  93 /  20  20  40  30  30
Corsicana           98  78  94  76  93 /  20  20  40  30  40
Temple             100  77  96  75  93 /  10  10  40  20  50
Mineral Wells      101  75  96  74  93 /   5   5  30  30  30

&&

.FWD Watches/Warnings/Advisories...
None.
&&

$$


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