Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX
FXUS64 KFWD 280033
Area Forecast Discussion
National Weather Service Fort Worth TX
733 PM CDT WED JUL 27 2016
Thunderstorms will continue to weaken through mid evening due to a loss
of heating. We will still keep some chance pops across the
eastern and southern zones and a slight chance elsewhere due to
the numerous outflow boundaries in the area.
The only other changes necessary at this time will be to adjust
the hourly temperature and dewpoint grids where thunderstorms
have temporarily modified the air.
/ISSUED 655 PM CDT WED JUL 27 2016/
Thunderstorms which developed earlier this afternoon near the Red
River have pushed south of the Metroplex as of 00Z TAF issuance
time. Some spotty thunderstorms will remain possible over the next
few hours in the vicinity of two converging outflow boundaries along
a KGDJ-KCPT-K76F line, but any additional activity is expected to
remain south of the Metroplex sites. For Waco, have continued VCTS
until 28/01Z to account for ongoing convection, but this too is
beginning to wane with the loss of daytime heating.
The forecast for Thursday is once again a challenging one as we
remain under the influence of a mid-level shear axis and subtle
areas of enhanced lift pivoting around a weak upper-low near the
For the Metroplex sites: opted to prevail VCSH during the morning
hours as continued weak isentropic ascent/warm advection may get
elevated showers going again. As this activity diminishes during
the mid-morning, surface heating may encourage thunderstorm
development during the afternoon. Confidence in thunder, however,
was not high enough to introduce VCTS, but will need to seriously
consider in future updates.
For the Waco TAF: confidence in the occurrence of thunder is
higher given the closer proximity to a weak vort lobe, and have
prevailed VCTS from 28/16Z to 28/21Z accordingly.
Outside of convection, anticipate VFR conditions and light south
to southeast winds at 10 kts or less.
.PREV DISCUSSION... /ISSUED 355 PM CDT WED JUL 27 2016/
The main highlights for this forecast package will be rain
chances over the next several days and into the early portion of
the weekend. For the latter half of the weekend and into next
week, the upper air pattern favors one that should result in hot
and mostly dry conditions.
For the rest of this afternoon, showers and thunderstorms will
continue as daytime heating and additional convection develops
along outflow boundaries. The main culprits for convection this
afternoon are the mid-level deformation axis as seen in water
vapor imagery and RAP H5 fields across North TX with the main
impetus for convection across Central TX being along modified sea-
breeze outflow lifting northward. The very moist regime, slow
storm motion and weak deep layer shear has resulted in efficient
rain producers across North and Central TX this afternoon.
There have been a few strong convective outflows, but generally
the moist environment makes has made it a bit more difficult to
generate a large amount of negative buoyancy within and below the
convective clouds. That being said, we will maintain a risk for
generally sub-severe downbursts as precipitation loading may
result in winds in the 40 to 50 MPH range. One area that we will
watch will be across southeastern zones where sufficient heating
and a bit more in the way of mid-level dry air exists. This may
promote a slightly higher risk for downbursts across this part of
North and Central TX.
Convection for the most part should wane through the evening
hours before subsiding with the loss of daytime heating. I will
maintain slight chance PoPs (with higher chances across NE zones)
as most of the synoptic models show a shift in the upper air
pattern. This shift places much of the forecast area in northerly
to northwest flow aloft. Most models advertise some DCVA in the
north to northwest flow aloft and given the moist regime, this
warrants at least keeping slight chance PoPs across the area.
Convection is expected to continue Thursday morning across much of
the area as shortwave troughs traverse the north/northwest flow
aloft. The airmass is expected to remain rich and moist and as a
result, instances of minor flooding will be the main risk with
showers and thunderstorms. Similar to today, there will be a gusty
downburst wind threat, but poor lapse rates and generally modest
wind shear should limit overall storm organization.
Rain chances will continue into Friday and Saturday as the swift
north/northwest flow pattern continues. 20-30 percent PoPs were
introduced Friday afternoon into Saturday morning given that a
few lobes of mid/upper level vorticity are forecast to sweep
through the area.
Beyond Saturday, near triple digit heat is expected to grip North
and Central TX. Wind speeds are generally expected to be fairly
light through this portion of the forecast. The weak winds should
prevent deep boundary layer mixing. As a result, relative
humidities will continue to range in the mid-30 to 40 percent
range. While this may limit a larger fire weather concern for
areas that miss out on rain over the next several days, heat
index values will likely climb back into the 102 to near 105
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 76 94 77 97 78 / 20 40 10 30 20
Waco 77 97 75 99 76 / 30 40 20 20 10
Paris 73 90 73 94 74 / 40 40 20 30 20
Denton 73 93 74 96 74 / 20 40 10 30 20
McKinney 74 93 75 95 75 / 30 40 10 30 20
Dallas 77 94 76 98 79 / 20 40 10 30 20
Terrell 75 93 75 95 76 / 30 40 20 30 20
Corsicana 76 96 75 96 77 / 30 40 20 20 10
Temple 75 96 75 97 75 / 30 40 20 20 10
Mineral Wells 72 94 72 97 73 / 20 40 5 20 10