098 
FXUS64 KFWD 290311
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1011 PM CDT Tue May 28 2019


.UPDATE...
Dryline convection came close but remained just north of the Red
River as it spread east, and additional storms across the
northwest appear unlikely this evening. The Severe Thunderstorm 
Watch was hence allowed to expire on time at 10 PM. There may be 
redevelopment over Southwest Texas during the overnight hours as a
disturbance moves quickly northeast out of Mexico, and some of 
these storms may affect the western third of the region prior to 
daybreak. Better rain chances still appear likely Wednesday 
afternoon and evening associated with stronger disturbance and a 
cold front. Otherwise, elevated showers and storms over Central 
Texas warranted the addition of isolated thunder across the 
southern-most counties through about 1 AM. 

30

&&


.AVIATION... /Issued 658 PM CDT Tue May 28 2019/
/00Z TAFs/

Thunderstorms firing along a dryline should remain west of all
airports this evening, though occasional impacts on northwest 
inbounds may occur through midnight local. Otherwise, south winds 
of 15 to 20 kts and VFR conditions can be expected through the 
evening. Overnight, another surge of stratus should reach KACT
around 06Z, then the DFW Metroplex around 09Z. Conditions should
improve to VFR around midday Wednesday.

A fairly active convective period is expected during the afternoon
and evening on Wednesday as an upper level disturbance and a cold
front traverse the region. Isolated thunderstorms will be 
possible during the afternoon, with more numerous storms expected 
Wednesday evening as the front moves in from the northwest. The 
DFW area airports will have a TEMPO group for thunder beginning at
22Z. This group ends at 02Z in the extended portion of the DFW 
TAF, but at 00Z for the rest of the Metroplex TAFs (at the end of
the forecast period). This will be followed by a shift to 
northwest winds as the front pushes through the area around 
30/02Z. The front will slow down, arriving much later at the Waco 
area, so no TEMPO group is necessary at KACT at this time.

30

&&

.SHORT TERM... /Issued 334 PM CDT Tue May 28 2019/
/Through Tonight/

Main concern through the short term is the potential for surface-
based convection to occur across our west and northwest zones late 
this afternoon and evening. As of 2pm, a surface dryline was 
draped roughly from Childress southwards towards San Angelo. To 
the east, a very unstable airmass exists with moderate deep-layer 
shear. Ascent is not terribly strong, and mostly limited to low- 
level convergence in the vicinity of the dryline, with a subtle 
shortwave lifting northeastward over the I-35 corridor. A few 
recent convective attempts have been noted on visible satellite 
imagery just east of the dryline. However, these updrafts seem to 
be struggling as they encounter a fairly strong capping inversion 
with dry air just above, as noted by recent AMDAR soundings. We'll
have to continue monitoring for possible convective initiation 
roughly from Comanche to Wichita Falls through the peak heating 
hours today, as some of these initial failed CI attempts may help 
to cool/saturate the capping layer. Initiation seems more likely 
northwest of the forecast area, where more favorable ascent and 
instability coincide. Should deep convection occur, storms would 
have the potential to become strong or severe with primarily a 
hail and wind threat. Relatively marginal shear could limit the 
potential for supercell organization, but some supercellular 
structures with struggling mesocyclones would be possible. These 
cells would likely remain west of the I-35 corridor or possibly 
skirt our Red River counties before dissipating with loss of 
heating and increasing CIN.

Otherwise, the aforementioned subtle shortwave is resulting in
mid-level ascent/saturation farther east, where occasional
showers/virga and even a couple lightning strikes have occurred. 
Some brief rain or a rumble of thunder will remain possible out 
of this high-based activity through early evening as it continues
to move northeastward out of the I-35 corridor. Overnight, a 
relative minimum in precipitation chances should occur while a 
front approaches from the northwest. This front will begin 
initiating new storms around daybreak Wednesday, likely just west
of the CWA. These features will be the main concern for tomorrow,
as discussed below. 

-Stalley

&&

.LONG TERM... /Issued 334 PM CDT Tue May 28 2019/

Wednesday afternoon will start with a complex of thunderstorms
across central Texas making its way eastward ahead of the cold
front, and low clouds across north Texas. SPC has moved the
enhanced risk further southwest to include the metroplex which is
a change from the slight risk that has been in place for
Wednesday. A mid-level shortwave with embedded strong 
southwesterly flow will overspread north central Texas atop a 
moist boundary layer. This will provide excellent parameter space 
ahead of the cold front as it moves southeastward. Steep mid-level
lapse rates and strong vertical shear would support the threat of
large hail with these storms. Ahead of the cold front convection 
allowing models suggest the development of supercells within the 
warm sector tomorrow afternoon. If these supercells do develop 
from the metroplex and eastward, all modes of severe weather are 
possible, including tornadoes. Mitigating factors for supercells 
in the warm sector would be the possibility of a strengthening cap
due to mid- level dry air moving in from southwest to northeast. 
While hodographs have excellent curvature, a weakness and slight 
backing of the winds in the 800-650mb layer may result in less 
organization to the convection. PWATs are forecast to reach 2+ 
inches by 00z Thursday across much of north Texas which is well 
above normal and 90th percentile values (even above the daily max 
values for most days at the end of May/early June). Overall QPF 
has trended downward with the latest WPC guidance across most of 
north Texas; however widespread rainfall amounts of 1.50 - 2.50 
inches including and northward of the metroplex seem reasonable. 
Rainfall over the last 7 days hasn't been particularly impressive,
but much of the area remains well above normal for late May. And 
with the possibility of locally higher amounts in convective 
bands, have opted for a Flash Flood Watch for portions of north 
Texas.

As the front moves through, thunderstorm chances will diminish
from west to east Thursday morning. Most of the area will be dry
Thursday, but another shortwave will move through Texas along the
zonal 500mb flow on Friday and keep at least a chance for thunder
across much of Central Texas. A similar setup is expected for
Saturday too before 500mb flow becomes more northwesterly across
Oklahoma and North Texas as a weak ridge builds to the south. This
will still keep at least some thunderstorm mention across North
Texas through early next week from any complexes that form to our
northwest, but coverage and the potential for severe weather
remains low.

Elsenheimer

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    75  87  68  85  67 /  10  90  80   5  30 
Waco                76  88  70  86  68 /  10  40  70  10  30 
Paris               73  85  66  83  63 /  20  50  90   5  20 
Denton              74  85  65  83  65 /  20 100  70   5  20 
McKinney            75  85  66  83  65 /  10  80  80   5  20 
Dallas              76  88  69  86  68 /  10  80  80   5  30 
Terrell             75  87  69  86  66 /  10  40  80   5  20 
Corsicana           75  87  69  84  67 /  10  30  70  10  20 
Temple              75  88  70  86  69 /  20  20  60  20  20 
Mineral Wells       72  85  62  83  63 /  20  90  50   5  30 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from 7 AM CDT Wednesday through Thursday 
morning for TXZ092>095-102>106-117>120-131>133.

&&

$$

30/91