Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX
FXUS64 KFWD 241755 AAA
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1255 PM CDT SUN JUL 24 2016
VFR conditions are anticipated through the TAF period, but the
potential for thunderstorms impacting all sites will increase on
Monday afternoon. In addition, surface winds are expected to back
to an easterly or east-southeasterly direction tomorrow afternoon
but--outside of thunderstorms--should remain under 10 kts.
For the remainder of today, it appears as if subsidence on the
fringes of the upper-high should keep convection just to the east
of the TAF sites this afternoon and evening. That said, we will
need to monitor for any westward-surging outflow, which could
impact the Metroplex sites later this evening (after about 03Z)
with brief gusty east winds for an hour or two. This potential is
too low to include in the 18Z TAFs, however.
An upper-level disturbance will track into the region on Monday,
and bring an increasing threat for showers and thunderstorms to
the area. For this TAF issuance, opted to insert VCTS after 17Z
at all airports as this appears to be around the time convective
inhibition will erode. Any thunderstorms in this increasingly
moist environment will be capable of producing brief heavy
rainfall and erratic downburst winds.
Showers and storms are still expected to pop up over eastern
zones this afternoon as the easterly wave over Louisiana
approaches. The main adjustments to this update will be to add
POPs in the northeast for the overnight hours based on multiple
hi-res solutions picking up on nocturnal redevelopment in this
region in the vicinity of the approaching disturbance. Otherwise,
another day of triple digit high temperatures in many locations is
expected today, before a slight cool-down and better rain chances
.PREV DISCUSSION... /ISSUED 420 AM CDT SUN JUL 24 2016/
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
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 copious 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.
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 101 81 96 79 95 / 10 10 50 20 30
Waco 101 78 96 76 93 / 10 10 50 30 40
Paris 99 76 93 75 94 / 20 30 50 20 20
Denton 100 78 95 75 94 / 10 10 40 20 30
McKinney 99 78 94 76 93 / 10 20 50 20 20
Dallas 101 80 95 79 94 / 10 10 50 20 30
Terrell 98 77 93 76 93 / 20 20 50 20 30
Corsicana 98 78 94 76 93 / 20 20 60 20 30
Temple 100 77 96 75 93 / 10 10 40 30 50
Mineral Wells 101 75 96 74 93 / 5 5 30 20 30