Damaging Wind and Lightning Strike in Texas, July 28, 2020

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1245 PM CDT Tue Jul 28 2020

.AVIATION [18z TAF Issuance]...

Quite the busy and messy day so far as widespread convection con-
tinues to develop and move across SE TX. Given the very tropical
airmass over the area and daytime heating, will be expecting all
this activity to subside by this evening. Cannot rule out the re-
development of some patchy fog/low clouds tomorrow morning given
the wet grounds/light winds. Otherwise, this pattern is favoring
very similar conditions for tomorrow. Started mention of VCSH at
the coast around 10Z...then spreading inland through the rest of
the morning/early afternoon. 41

&&

.PREV DISCUSSION...  /ISSUED 401 AM CDT Tue Jul 28 2020/

SHORT TERM...(Today through Wednesday)

A well defined upper level low was located over SE TX early this
morning. This feature coupled with a weak coastal trough and
abundant low level moisture should set the stage for scattered to
numerous showers and thunderstorms. Fcst soundings don't show much
in the way of capping and convective temperatures are between
84-87 degrees which should be met by mid morning. There is also a
disturbance/outflow heading south from North Texas late in the day
This feature will need to be watched for additional storms over
the northern zones late in the afternoon and potential for merging
storms and brief heavy rain. Temperatures are tricky today and
will be influenced on when storms initiate. Will lean toward
persistence and think today's values will be similar to yesterday.
Any residual precipitation will end this evening with the loss of
heating and skies should begin clearing between 02-03z.

Models are not showing much in their respective mass fields on
Wednesday but PW values remain above 2.00 inches. Can't find much
of a trigger other than daytime heating as the upper low is well
SW of the region and has filled a bit. Fcst soundings don't show
much in the way of capping but convective temps warm to between
89-92 degrees so it'll take some heating to get things going.
Will still go with high end chance PoPs for Wednesday aftn. 43

LONG TERM [Wednesday Night Through Tuesday]...

Calm weather conditions are forecast Wednesday night into Thursday
morning over Southeast TX once lingering storms dissipate. The
proximity of mid to upper level ridging will help subdue overall
shower and thunderstorm development during the day Thursday.
However, fairly good low level moisture will be moving across the
local area during the day Thursday, with PWs ranging between 1.8 and
2.1 inches. The combination of diurnal heating and available
moisture could still be sufficient to produce isolated to
scattered showers and isolated thunderstorms Thursday afternoon,
particularly across the central and eastern portions of the CWA.
Additionally, heat indicies will rise with most areas looking to
experience a heat index of 103 to 106 deg F.

Thursday night into Friday, the ridge will shift eastward into
Southeast CONUS in response to an upper level trough moving eastward
into the Great Plains region. The trough is expected to extend south
Friday with its axis moving across Central Oklahoma and Central
Texas sometime Friday and will meander over this region through
Saturday morning. Drier air will filter into the local area Friday
and will help keep chance of showers and thunderstorms low (20-30%).
Another upper level trough over the Saskatchewan and Manitoba Canada
region will dig south into north central CONUS. This feature will
help push the stagnant trough situated over the western Great Plains
slightly eastward Saturday into Sunday, somewhat
broadening/strengthening and a surface frontal boundary will then
extend across Northern Texas. This will bring back an unsettled
weather pattern to Southeast TX throughout the weekend. Additionally,
we may have storms developing to our north move into our region from
time to time, which is something some models struggle to show so far
out in the forecast period.

Early next week, the northern portion the trough and associated
upper low will be able to progress into the Great Lakes region
Monday; however, the southern end of the trough will remain fairly
motionless. If it plays out this way, it could keep the trough axis
over or near Southeast TX through Tuesday and stall the front to our
north. Rain chances for our local area will probably depend on how
this trough moves, or doesn't move. At this time, kept PoPs modest
for both Monday and Tuesday. 24

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      95  76  94  77  96 /  40  30  30  10  20
Houston (IAH)              93  77  93  78  94 /  60  40  50  10  30
Galveston (GLS)            89  82  89  82  90 /  60  30  50  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&