714 
FXUS64 KFWD 071948
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
248 PM CDT Sun Jul 7 2019


.SHORT TERM...
/Through Monday Morning/

Visible imagery shows a couple of areas of vertically developed 
cumulus this afternoon. The first is east of the US HWY 75 
corridor/north of I-20. LAPS/RAP analysis indicate that 
instability in excess of 3000 J/kg with decreasing convective 
inhibition is in place. Convergence along outflow generated from 
a compact cluster of thunderstorms across the Ark-La-Tex may aid 
in continued upshear development deeper into North Texas. With 
instability being the greatest across Northeast TX...the 
potential for more widespread convection exists here and I've 
increased PoPs to near 50% for the rest of the afternoon. The 
greater instability also supports more vigorous updrafts and 
despite weak wind shear...20 to 25 degree dewpoint depressions 
will support a strong to marginally severe downburst risk.

The other area that will have a risk for afternoon showers and
storms will be across the Big Country (mainly areas near and west
of the US HWY 281 corridor). While instability isn't quite as
large here...it still remains near 2000 J/kg. In addition, modest
convergence along remnant outflow boundaries may serve as focusing
mechanisms for convective initiation. I'll maintain a 20-30 PoP 
to address this potential. A gusty downburst risk will also exist
here thanks to the hot and well mixed PBL. Along the immediate 
I-35 corridor...it's possible that low PoPs at this time are 
overdone as RAP analysis suggests that the spine of a mid-level 
ridge (albeit it is struggling to build) will be in place. This 
could stunt updraft development as the airmass aloft remains warm 
and dry. I'll still maintain some low PoPs along the I-35
corridor, generally north of I-20 this afternoon and into the 
early evening hours given that we will approach and possibly 
exceed convective temperatures. Gusty winds and brief heavy rain 
will be the primary weather concerns. The remainder of the area
(Central Texas) is expected to remain rain/storm-free.

Overnight...shower and storm coverage will decrease with the loss
of daytime heating. Overnight lows will be around seasonal normals
with most locales falling into the 70s. A few of the urbanized
regions may remain near 80 degrees for overnight low temperatures.

Bain

&&

.LONG TERM...
/Tomorrow through Next Weekend/

The main story in the extended period is building heat through at
least mid-week, with temperatures approaching 100 and heat 
indices around 105-110 in many locations Tuesday into Wednesday.

Other than that, a few showers and storms will try to hang tough 
tomorrow afternoon and evening, especially towards the Big
Country. Despite mid-level ridging attempting to build across the
region early this week, convection generated over the southern
High Plains through tonight will likely eject one or more
MCVs/impulses towards western North Texas tomorrow. Diurnal
heating, an uncapped environment, and the aforementioned mid-level
feature will likely yield isolated to scattered convection by
afternoon. Similar to prior days, weak 500mb flow will ensure that
individual cells remain unorganized. However, tall buoyancy
profiles (with MLCAPE around 1000-2000 J/kg) and steep low-level
lapse rates could encourage a strong downburst or two in the most
robust cores, most likely west of US-281. 

As for the heat, tomorrow should see heat indices solidly in the
100-105 range, especially near the I-35 corridor, where mid 90s
highs and lower 70s dew points will intersect. While heat 
advisory criteria could be achieved in a few spots, it appears too
localized for issuance at this time, especially considering a 
potential convective influence (e.g., clouds, outflow) from the 
west.

The heat builds in earnest Tuesday into Wednesday as a mid/upper
anticyclone builds to our west/northwest and 925-850mb temps rise
further. Highs will climb into the upper 90s to near 100,
combining with stubbornly high boundary-layer moisture to produce
heat indices around 105-110. The one possible source of relief
late Wednesday into Thursday may be related to a distant savior 
(in the form of a sharp shortwave impulse) over the northern 
Plains and upper Midwest. While this system's attendant cold 
front will remain well north of North Texas, guidance suggests 
that it could kick off one or more convective clusters that sink 
south into a reservoir of surface-based buoyancy over the Ozarks. 
The GFS solution seems too aggressive with its convective "chain 
of events" into North Texas late Wednesday into Thursday, but 
a weaker form of this evolution seems plausible, given northerly 
flow aloft on the east side of the amplifying ridge. Therefore, 
the forecast now advertises slight-chance PoPs across parts of the
region through Thursday.

Although this evolution could stunt our warming trend some, the
more likely scenario is that we maintain the heat through the end
of the week, with temperatures remaining in the mid/upper 90s
through Friday. At the least, surface dew points should fall some
in response to weak dry-air advection from the northeast. 


Picca

&&


.AVIATION... /Issued 1243 PM CDT Sun Jul 7 2019/
/18 UTC TAF Cycle/

Concerns---Low VCTS potential at Metroplex TAFs. Slight wind
shifts to the west and possibly northwest this afternoon.  

VFR is forecast to prevail at all TAF sites...outside of any
SHRA/TSRA. Mid-level high pressure should keep the coverage of
convective activity low, but confidence is not high enough to
explicitly exclude it from the TAF. As such, I'll maintain a brief
window (2 hours) for VCTS at all TAF sites...though confidence is
low to medium. Outside of lightning, the main hazards will be 
gusty/erratic outflow winds and brief heavy rain which may reduce 
vsby down to MVFR or IFR. There will still likely be impacts to 
the Bonham cornerpost/eastbound departures...as well as for Bowie 
cornerpost/westbound departures. The threat for SHRA/TSRA INVOF 
TAF sites will decrease drastically after 00 UTC Monday. Otherwise
southwest winds may become northerly this afternoon and into the 
early evening hours. Speeds may be light enough---assuming the 
wind shift is not associated with TSRA---to maintain south flow 
operations. 

For Waco...the degree of mid-level ridging will preclude
convective chances and the best potential for MVFR resides
south and southeast of Waco. South to southwest winds will
prevail. 

Bain

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    78  95  78  98  79 /  20  20  20   5   5 
Waco                76  95  77  98  77 /   5  10  10   5   5 
Paris               75  92  75  93  76 /  30  20  10   5   5 
Denton              77  94  78  99  78 /  20  30  20   5  10 
McKinney            76  95  77  97  78 /  20  20  10   5   5 
Dallas              80  96  78  99  79 /  20  20  10   5   5 
Terrell             76  94  77  98  77 /  10  20  10   5   5 
Corsicana           76  93  75  94  76 /   5  10  10   5   5 
Temple              75  95  75  98  76 /   5  10  10   5   5 
Mineral Wells       74  93  75  99  76 /  20  30  20   5  10 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

11/24