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Area forecast discussion...updated 
National Weather Service Fort Worth Texas
1120 PM CDT Sat Aug 27 2016

Aviation...
the isolated to scattered showers and thunderstorms that developed
during the day Saturday to the west and east of the I-35 corridor
had dissipated as of 0420z. There will be a slight chance of
showers and thunderstorms Sunday in the metroplex, but the chances
at the individual airports are too low to mention in their tafs at
this time. Scattered showers and thunderstorms are expected across
central Texas Sunday, so will include thunderstorms in the vicinity starting at 18z in the
Waco taf. Otherwise, VFR conditions will prevail with southeast to
east winds at less than 10 knots.

58

&&

Update...
earlier convection which developed across our western zones this
afternoon has ceased with the loss of heating. Farther to the
east, a few more showers and storms rotating around the northern
periphery of an upper-low will slide into portions of our eastern
counties--Van Zandt, Henderson, and Anderson in particular. Have
left in some low-end chance pops to account for this westward-
moving activity through 11 PM or so. Expect most activity will
have waned by then, although we've retained the low (10%) isolated
thunder wording overnight across the southeastern third of the County Warning Area
as this area will remain under the influence of moist easterly
flow near the upper-low/surface trough.

Regarding the fog potential overnight: we've opted to forgo
inclusion of patchy fog wording at this time. Earlier
precipitation coverage wasn't particularly widespread, and it
appears most locations will remain at or above their crossover
temperatures tonight. That said, given the slightly lower dewpoint
depressions across roughly the western third of the County Warning Area along
with gradual clearing, we could see some localized pockets of
light fog develop overnight west and south of the metroplex. We
will continue to monitor observational trends, however.

Made a few tweaks to the short term trends to bring US in line
with current observations. Otherwise, the rest of the forecast
package looks to be in fine shape.

Carlaw

&&



Synopsis...
rain chances will continue through a majority of the 7 to 10 day
outlook for a good portion of north and central Texas. The best rain
chances look to be on Tuesday mainly across central Texas as an upper
low lifts northward from the Gulf of Mexico. Thereafter, most rain
chances will be largely predicated on diurnal heating, as well as
any remnant outflow boundaries from previous days convection. The
Labor Day weekend may be wet for some with a low chance for a few
showers and storms.

&&

Short term (tonight through monday)...
showers and thunderstorms will likely continue this afternoon and
through the early portion of the evening hours. Current trends
would suggest that the best coverage of showers and thunderstorms
will generally be out across western zones where mesoscale ascent
along a diffuse convergence zone coupled with weak synoptic scale
ascent from a subtle shortwave aloft has resulted in the
development of scattered convection. Convection has really
struggled today across eastern zones, despite a slightly more
moisture-rich troposphere. It is plausible that the reduced
coverage of convection here is a result of slightly more subsident
air given the proximity of the mid-level ridge across the southeast
Continental U.S.. that being said, additional daytime heating will occur and
there should be a gradual uptick in convection, especially along
any residual outflow boundaries. With the unorganized
tropospheric wind field and precipitable water values ranging between 1.5-2",
slow storm motions will result in pockets of minor flooding. There
will be a low risk for a damaging downburst or two, but with a
smaller quantity of dry air aloft, this risk is not as high as the
past couple of days. Activity should decay with the
loss of daytime heating.

For tonight---patchy fog may be possible, especially for areas
that receive rainfall this afternoon and experience clear skies
and calm winds tonight. There still remains some uncertainty with
regards to exact locations so for now will abstain from
mentioning patchy fog in the worded forecast and let the evening
shift examine the potential. The other feature to watch for
tonight will be the magnitude of the coastal low across the Upper
Texas coast. I will keep a very low chance for an isolated shower or
thunderstorm (10%) in across the eastern third of the forecast
area tonight with the east flow moist flow continuing through at
least Sunday morning.

For Sunday---rain chances will increase slightly early Sunday
morning as east flow continues around the northern periphery of
the Upper Texas coast low. Most of the hi-res and global guidance
continues to push this feature down towards the south and
southwest down towards the coastal Bend. As a result, the wind
field across north and central Texas backs slightly to the northeast
through the day on Sunday. This may allow for a less direct fetch
of low level moisture which may limit the areal coverage of
diurnal convection across the region, certainly compared to the
last couple of days. As a result, i've lowered pops down to 20%
along the north to 30% across central Texas. With a slightly lower
coverage of showers/storms, i've nudged temperatures upwards by a
few degrees areawide, with the warmest conditions along and north
of I-20.

For Monday---the overall threat for showers and storms will
continue on Monday as the coastal low moves inland across south
Texas. The wind field may become slightly more favorable across the
region to allow for a slightly better feed of low level moisture.
The best threat for rain will be across southern zones with rain
chances tapering off to near 20 percent to the north. Similar to
Sunday, temperatures will be the warmest across northern zones
where a few more breaks in the cloud may prove sufficient to heat
areas into the low 90s. Mid to upper 80s are expected elsewhere.

&&

Long term (tuesday through friday)...
for Tuesday---diurnally driven rain chances will continue on
Tuesday with a persistent feed of low level moisture from the
east. Similar to Sunday and Monday, the highest coverage of
showers/storms will be relegated to central Texas. High temperatures
will rebound slightly, but with the widespread cloud cover, it's
likely that they will remain in the upper 80s across
southern/southwest zones to low 90s elsewhere.

For Wednesday and Thursday---warm conditions with temperatures in
the upper 80s and low 90s are expected. Diurnal rain chances will
continue on Wednesday and with no real apparent focus, i've
broad-brushed slight chance pops everywhere. On Thursday, there
does appear to be some synoptic scale ascent ahead of a shortwave
trough that is forecast to slide southeastward out of the Central
Plains. The best ascent and thus rain chances should be along and
northeast of a line from Gainesville to McKinney to Van.

For the Labor Day weekend---low rain chances will continue into
the first portion of the Labor Day weekend. Again, with no real
focus, i've inserted 20% pops area-wide with the most likely time
frame for showers and storms coming in the afternoon hours on
Friday. Saturday and Sunday appear dry for much of north and
central Texas at this time with perhaps a very slight chance for rain
across far eastern zones. For now I will advertise a dry forecast
areawide and new model output will be examined.

24-Bain

&&

Preliminary point temps/pops...
Dallas-ft. Worth 75 91 76 93 76 / 20 20 20 20 20
Waco 73 89 74 90 73 / 20 30 30 30 20
Paris 73 91 73 92 73 / 20 20 20 20 10
Denton 73 91 72 92 73 / 20 20 20 20 20
McKinney 73 90 73 92 74 / 20 20 20 20 20
Dallas 76 91 77 93 77 / 20 20 20 20 20
Terrell 74 90 74 91 74 / 20 20 20 20 20
Corsicana 74 90 74 91 74 / 30 20 20 30 20
Temple 73 88 73 88 73 / 20 30 30 40 20
Mineral Wells 72 90 72 91 72 / 20 20 20 30 20

&&

Forward watches/warnings/advisories...
none.
&&

$$

58/90

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