Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/13/19
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1021 PM CDT Fri Jul 12 2019
.UPDATE...
Fairly quiet night with the only action on radar being across the
eastern CWA where the outer bands of TS Barry introduce mainly
showers. Showers with an isolated storm cell will pass across
from the northeast to southwest through the early Saturday morning
hours. Slowly backing northerly winds will strengthen through
Saturday afternoon...Small Craft Exercise Caution flags now
hoisted over the eastern waters through mid Saturday morning.
While TS Barry`s most organized and strongest convection remains
to the south of the broad near 1000 mb surface low hugging the
Louisiana coastline, the 10 PM NHC forecast calls for the system
to briefly reach hurricane strength tomorrow morning before making
landfall over southern Louisiana as a strong Tropical Storm
tomorrow afternoon.
Barry`s impacts for us will be from his outer convective bands
that will periodically produce precipitation bands across
(primarily) the southeastern 2/3rds of the forecast area. Areawide
inland weekend rainfall will be under an inch across most counties
with the highest rainfall of between 1 to 3 inches occurring
along the upper Texas coastline and points offshore. There should
be enough early day peaks of sun in the broken clouds to provide
ample insolation to peak maxTs in the (very slightly cooler) lower
average mid 90s tomorrow. Very high 2.3 to 2.5 inch pwat air
moving in from the east will keep dew points high enough through
the day (low 70s) to produce 102 to 107 F heat indices. 31
&&
.PREV DISCUSSION... /ISSUED 640 PM CDT Fri Jul 12 2019/
AVIATION...
VFR conditions across the area tonight...brief SHRA around GLS
and LBX will be possible in the evening hours, but no major
impacts expected. Winds remain out of the N/NE at around 10kts.
Conditions remain mainly VFR through the remainder of the TAF
period. Some SHRA/TSRA and gustier winds associated with the
outer bands of TS Barry possible beginning tomorrow afternoon as
the system approaches the Louisiana coast. Coverage will be
isolated to scattered in nature, so for now have left VCSH/VCTS
in TAFs. Cady
&&
PREV DISCUSSION... /ISSUED 356 PM CDT Fri Jul 12 2019/
DISCUSSION...
- Tropical Storm Barry continues to move erratically but slowly
WNW off the Louisiana coast. Overall track forecast remains
unchanged with landfall in Louisiana.
- Main concern for SE Texas and the Upper Texas Coast will be for
an inflow band of Barry to set up along the coast Saturday night
into Sunday as Barry moves through Louisiana. This very moist
inflow band may cause locally heavy rainfall but flooding
impacts should be minimal.
- Hot conditions should continue this weekend and then next week
as high pressure ridging aloft builds over much of Texas.
SHORT TERM [Tonight Through Saturday]...
Starting to see showers/thunderstorms form to our NE/E this after-
noon as bands (rotating around Barry) approach the CWA. Have kept
with the best POPs over our eastern/coastal counties through this
evening, but still thinking that any activity that moves into the
area will have a hard time making it that far west (given all the
drier air aloft that was able to mix down).
The light/moderate offshore flow that has been in place has helped
to produce some rather hot temperatures along the coast. So far we
have seen upper 90s readings across our coastal counties this
afternoon (which typically average in the lower 90s)...with
Galveston possibly tying a rather long-standing high temperature
record.
With Barry making landfall early Sat over southern Louisiana, wrap
around moisture/outer storm bands, the best rain chances will stay
over the eastern half of the CWA on Sat. Thereafter, a lot will be
depending on the eventual track of Barry. 41
TROPICAL...
Tropical Storm Barry was located at 28.7N 90.9W which is where
aircraft recon found the lowest pressure of 993mb. The reality is
that visible satellite shows an exposed low level circulation in
this same area and TS Barry has been producing several of these
swirls. Deeper convection was still located south of the system as
it battles drier air to the north. The deep convection has been
helping keep pressures low so it will be interesting to see the
motion of this swirl in relation to the overall structure of TS
Barry and if there are any lowering of pressures under the
convection to the south. For now it seems more reasonable for deep
convection to start to wrap into this exposed center on visible
satellite imagery with TS Barry slowly drifting back NW again. NHC
forecast continues with slow motion and making landfall over
central Louisiana. All tropical guidance agrees with this track
and see no reason to deviate form it as the ridge over Florida
builds and helps nudge TS Barry into the weakness in the overall
ridging pattern left by an exiting trough over the Great Lakes.
Our main concern is more on Saturday into Sunday as Barry moves
north through Louisiana. Satellite has show a persist arcing
inflow band from the Texas Coast into the center of the system.
Models have this banding persisting and shifting north with time
as the system moves north. This means there could be some bands of
showers and storms to set up along the Upper Texas Coast and just
inland Saturday night into Sunday. The set up would support
training of storms but models have been pretty conservative with
rainfall amounts. The NAM has been the most aggressive with rain
bands setting up but it also the farther west with the track of
Barry compared to all the other models. Rainfall forecast during
this time keeps closer to GFS/ECMWF amounts which have been very
consistent of late. This calls for a max of 1-2 inches of rain
mainly along the coast with 0.5 to 1 inch possible along I-69.
The other issue is that this system could still wrap some drier
air into it from the NW and keep any banding off the coast. Higher
moisture does linger into Monday so there could even be some
showers and storms banding. Again locally heavy rainfall could be
possible during this time and why WPC has a marginal risk for
excessive rainfall and flash flooding. At this time flooding
impacts look minimal as antecedent conditions have been dry.
LONG TERM [Sunday Through Friday]...
The tropical section pretty much covers the weekend forecast so
we will focus on the forecast for next week. As TS Barry moves
north over the Miss River Valley, upper level ridging should build
over the area in Barry`s wake. This will allow for hot conditions
to continue with high temperatures in the mid/upper 90s. There
may be some lingering showers and storms Monday and Tuesday as
higher moisture lingers from Barry but dry conditions for the rest
of the forecast.
MARINE...
Tropical Storm Barry was located off the Louisiana coast this
afternoon with erratic storm motion but generally moving very
slowly to the WNW. Overall there should not be any marine impacts
from Barry as it moves inland Louisiana tomorrow. We might get
some small craft advisory conditions Saturday night into Sunday.
Otherwise winds turn around back to the south for next week with
moderate seas. Overpeck
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 76 95 77 93 75 / 10 20 30 20 10
Houston (IAH) 78 95 78 95 78 / 40 50 40 40 30
Galveston (GLS) 82 92 81 90 82 / 40 70 60 60 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 10 AM CDT Saturday for
the following zones: Coastal waters from High Island to
Freeport TX out 20 NM...Waters from High Island to Freeport
TX from 20 to 60 NM.
&&
$$
Discussion...31