SEPTEMBER 2018 - Very Wet Month Wrap Up

General Weather Discussions and Analysis
unome
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question for anyone who can answer - what causes the outflow-like circle, as on this morning's radar near Hull Airport/Sugarland ?

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srainhoutx
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It appears that tomorrow may be our "driest" day of the upcoming forecast period. Rain chances increase Friday and throughout the weekend into early next week.
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srainhoutx
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unome wrote:question for anyone who can answer - what causes the outflow-like circle, as on this morning's radar near Hull Airport/Sugarland ?
Martins flying out from roosting headed out the get their fill of mosquitos.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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tireman4
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000
FXUS64 KHGX 051136
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
636 AM CDT Wed Sep 5 2018

.AVIATION [12Z TAF Issuance]...

Latest radar trends show scattered showers and thunderstorms
mainly from Victoria to Matagorda. This activity was embedded
within an axis of higher moisture at 925mb/850mb along with
precipitable water values around 2.3 inches. Boundary layer flow
should be from the east to southeast which will keep this moisture
axis west and southwest of most of the terminals. Based on this
and hi-res short range guidance support, TAFs at KGLS/KLBX/KSGR
and KHOU will have some mention of VCTS for the early afternoon.
VCSH should be enough to cover convection for terminals to the
north. Activity should be ending 22-00Z.

The only other aviation impact is fog at KUTS. This looks to be
an isolated area and widespread dense fog is not expected.
Visibility should improve the next hour or two as mixing begins
with sunrise.

Overpeck

&&

.PREV DISCUSSION /Issued 350 AM CDT Wed Sep 5 2018/...

.SHORT TERM [Through Tonight]...
Radar imagery shows some streamer showers over the Gulf waters,
coastal counties, and even into Wharton and Fort Bend counties where
dewpoints are currently in the mid to upper 70s. Light
northeasterly winds prevail over land through the morning hours,
while onshore flow remains over the Gulf waters. Partly cloudy
skies will become mostly cloudy during the afternoon hours as
showers and thunderstorms start to bubble up. Overall, short term
guidance looks to keep most of the coverage this afternoon in the
area with best moisture, which is mainly west of I-45 and along
the coast. An axis of convergence (both speed and directional) is
also draped over this region which should assist in development.
Convective temperatures today along the coast will be in the upper
80s, while precipitable waters across the region will be between
2.0 to 2.25 inches.

North of I-10, showers and thunderstorms will be more widely
scattered. The HRRR and RAP13 show a weak boundary in the wind
field late in the afternoon hours which could help to produce a
band of showers over our far the northern counties. Not as
confident that we will see thunderstorms north of I-10 this
afternoon as convective temperatures will be harder to reach (low
90s), lack of instability, and fairly stable lapse rates. With
less coverage today, high temperatures will be able to warm into
the upper 80s to low 90s.

Hathaway


.LONG TERM [Thursday through the Weekend]...
Thursday looks to be both the warmest and driest day this week.
Still expecting a chance for showers and thunderstorms, but
precipitable waters will be drier and heights will build through
the day. Friday, precipitation ramps back up with overall better
coverage as heights fall across the region in response to the
remnants of tropical system Gordon moving northwestward through
parts of Northern Louisiana, Southern Arkansas, and Oklahoma. With
an upper level trough to our west and elongated ridge over the
Eastern Seaboard, we will remain in an area of weakness through
the beginning of next week. Therefore, periods of showers and
thunderstorms will continue through the weekend, mostly developing
along the mesoscale breezes during the day time hours before
dissipating near sunset. Overnight, early morning showers will
likely be generated over the Gulf waters. Additionally, high
temperatures through the remainder of the weekend will rise into
the low 90s further inland and into the upper 80s along the coast.
Low temperatures through the next few days dip into the low to
upper 70s. Overall, the forecast in the extended time frame does
not look to vary much day to day.

Hathaway


.MARINE...
Scattered showers and thunderstorms have formed along the coast from
High Island and then between Galveston and Freeport. This activity
is expected to slowly push inland through the morning hours with
surface convergence along the coast. The storms may cause gusty
winds to near gale force along with briefly higher seas. Otherwise
moderate southeast winds can be expected today into Thursday. Winds
turn to the southeast and south for the end of the week and drop
below 10 knots. Moderate seas will slowly decrease through the end
of the week. Higher period swells have been moving through the
offshore waters with 8 second periods at the 42019 buoy. This swells
may impact the middle and lower coasts more than the Upper Texas
Coast. Tropical Storm Gordon has moved inland through AL/MS and
should track NW towards Arkansas.

Overpeck


&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 92 75 93 75 92 / 30 20 40 40 60
Houston (IAH) 91 75 90 76 89 / 40 20 40 30 60
Galveston (GLS) 88 80 87 81 87 / 60 40 50 50 70

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...None.

&&

$$


AVIATION...Overpeck
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tireman4
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HGX Forecast
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Are there any cold fronts in the long range forecast? Will we have to wait For October?
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ticka1 wrote:Are there any cold fronts in the long range forecast? Will we have to wait For October?
I posed this same question earlier this morning :D
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12z GFS shows another low pressure enter the BOC....moves it north into SETX
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Rip76
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mcheer23 wrote:12z GFS shows another low pressure enter the BOC....moves it north into SETX
Time frame?
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Rip76 wrote:
mcheer23 wrote:12z GFS shows another low pressure enter the BOC....moves it north into SETX
Time frame?
About 8–10 days from now.
unome
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srainhoutx wrote:
unome wrote:question for anyone who can answer - what causes the outflow-like circle, as on this morning's radar near Hull Airport/Sugarland ?
Martins flying out from roosting headed out the get their fill of mosquitos.
amazing, thank you !
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jasons2k
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srainhoutx wrote:
unome wrote:question for anyone who can answer - what causes the outflow-like circle, as on this morning's radar near Hull Airport/Sugarland ?
Martins flying out from roosting headed out the get their fill of mosquitos.
Thank you, I have been asking this for years and you are the first person to answer it. It looks similar to the bats in Central Texas, but it's the wrong time of day....
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srainhoutx
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Today looks to be somewhat quieter due to a bit of 'drier' air, but PW's increase again on Friday to 2 inches and likely will increase further over the weekend into early next week. A general 2 to 4 inches of rainfall with isolated higher amounts look likely for a large chunk of Texas over the next 7 Days. Enjoy the "Wet Pattern"... ;)
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tireman4
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Long Discussion today....

FXUS64 KHGX 061116
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
616 AM CDT Thu Sep 6 2018

.AVIATION [12Z TAF Issuance]...

Fog impact has not been as severe as anticipated in localized
spots, so have stepped back to MVFR or VFR with TEMPO IFR at SGR
and LBX this morning. Dry air is at the edge of our area, and
should make for a quiet day at the northern terminals. From IAH
coastward, still have potential for VCTS, though IAH may be an
aggressive northern extent. Overnight, may see potential again for
patchy fog, but at this time only go MVFR at LBX.

Luchs

&&

.PREV DISCUSSION /Issued 409 AM CDT Thu Sep 6 2018/...

.DISCUSSION...

Overall expect a wet weather pattern to continue through the
weekend with showers and thunderstorms possible each day. There is
a chance for drier conditions next week but depends upon whether
higher moisture lingers over the region or not. Locally heavy
rainfall like the last few days will continue to be a possibility
but very isolated.


.NEAR TERM [Through Today]...

Satellite shows a few remnant high clouds remaining late tonight,
particularly around and east of the Houston metro. Observations
southwest of the metro indicate at least some localized fog
development, but satellite also shows that this fog is confined to
known foggy spots, and widespread development has not yet begun.
With scraps of high clouds, it may well never occur.

Water vapor imagery shows us being impacted by the tail end of
Gordon in two unique ways, depending on how far inland you are.
There is a plume of more moist air associated with the remnants of
the storm`s core being advected down along the coast - because of
this, PoPs are quite high for today near and over the Gulf. Further
inland, dry air from the storm`s subsident fringe is bringing in
markedly drier air (1.5-1.75 inches versus 2+ inches per GOES-East`s
total precipitable water product), and so I hold with only slight
chance to low end chance PoPs there. Like yesterday, today should be
pretty hot, particularly deep inland where drier air and sunnier
skies should allow for temps rising up into the mid 90s.


.SHORT TERM [Tonight Through Saturday]...

For the most part, I expect showers to wind down per the daily
pattern as we lose solar energy towards evening, except over the
Gulf, which will of course see its typical nocturnal increase in
coverage deeper into the night, particularly with the lingering
weakness in the 500 mb height field left by Gordon. That
said...the HRRR, TTU-WRF, and RAP - and to a lesser extent the
WRF-ARW and WRF- NMM - show an almost front-like boundary set up
in the surface wind field in Gordon`s wake around East Texas. The
potential convergence there could generate a band of showers that
are why I do not go totally dry way up north this afternoon, and
keep slight chances lingering into tonight. Not sure if we`ll
actually be able to generate much, especially into the evening
hours on any such boundary, but that its appearance is relatively
common in high res guidance makes me want to keep at least some
low probabilities in there.

Friday looks largely similar to today, albeit without the dry pocket
of air present over points well inland, and so I paint my PoPs with
a much broader brush and have cloudier conditions. As one might
expect along with that, I keep temperatures a little cooler, with
even the warmest locations only getting into the lower 90s. That
said...I notice that the guidance is not handling the current dry
pocket of air to our northeast particularly well, and there is a
chance I`m overdoing things a bit. If this drier spot is more
persistent than the models suggest, rain chances up north may be a
bit more aggressive than they need to be up there. Something to keep
an eye on...

Luchs


.LONG TERM [Saturday Through Thursday]...

I`m sure most people in SE Texas were quite frustrated that last
weekend was more wet than dry. I`d like to say we will have a dry
weekend in store for you, but I`d be lying at that point. Overall
there is a weak upper level pattern over much of the central U.S.
with a broad trough axis expected to be in place by Saturday
morning. Through the weekend the main upper low moves from the
Plains towards the Great Lakes. This leaves a shear axis
stretching from Chicago back southwest towards SE Texas. A
surface front trails this system parallel to the shear axis aloft.
Over the weekend this front slowly pushes into SE Texas before
stalling. Basically there should be enough cold pool generation
from convection to support a frontal push. This frontal boundary
remains a focus for convection going into the mid of next week.
Models hold onto generally 2 to 2.3 inches of PWAT through the
weekend with any "drying" occurring by mid week. The ECMWF stays
on the wet side of the forecast with higher PoPs while the GFS
backs off and has somewhat drier air move into parts of SE Texas.
Given these differences, the forecast splits the difference goes
with a blend since its possible this "drier" air does not reach
SE Texas.

So what does this mean for the forecast? It means 60-70 percent
chances of showers and thunderstorms for the weekend and 40 to 60
percent chances Monday into Wednesday. Given the weak flow aloft
and high PWAT airmass, any stronger storms could produce locally
heavy rainfall. Mainly any storms that can achieve 2 inches of
rain an hour will pose a threat for flooding. Overall the chances
of this happening are low, but know that the atmosphere has the
potential for this to happen. Overall severe threat looks low
given the moist atmosphere with expected lapse rates closer to
moist adiabatic than not.

These types of convective regimes wreak havoc on the temperature
forecast. High temperatures depend largely upon the coverage of
showers and thunderstorms. With greater coverage over the weekend,
high temperatures in the upper 80s for most areas looks on track.
There will certainly be areas that may only stick in the low 80s
and some that could reach the 90s. With less thunderstorm activity
for next week, high temperatures in the low 90s looks reasonable.

Overpeck


.MARINE...

Data from the 42019 buoy showed some higher period (8-11sec) waves
moving through the offshore waters of the Upper Texas Coast
yesterday. Wave periods have dropped off to around 6 to 8 seconds
with wave heights decreasing. This should be the end of any wave
action generated by Tropical Storm Gordon when it was in the Gulf.

Moving forward into the weekend winds should be fairly light from
the southeast to south and then becoming southwest Sunday into
Monday. A frontal boundary stalls inland during this time allowing
for light winds. Seas will be decreasing from 2 to 4 feet down to
2 feet or less at times for the weekend.

Overpeck


.FIRE WEATHER...

No concerns for fire growth as winds will be light, humidity will be
well above critical values, and ERC values across the area are near
or above the 50th percentile. The major concerns would instead be
meeting prescriptions on the other end for sufficient activity in
any planned prescribed burns. A particular issue may be a virtually
complete lack of 20 foot winds above 5 mph.

Luchs

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 94 75 93 74 89 / 30 30 50 50 60
Houston (IAH) 92 76 90 75 89 / 30 30 60 40 60
Galveston (GLS) 86 80 86 80 88 / 70 50 70 50 60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...None.

&&

$$

DISCUSSION...Overpeck
NEAR TERM...Luchs
SHORT TERM...Luchs/Overpeck
LONG TERM...Overpeck
AVIATION...Luchs
MARINE...Overpeck
FIRE WEATHER...Luchs
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Keep the rain away from the Brazos Valley Friday and Saturday.

It can come back on Sunday.
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Big time rains here in Wharton County right now. We probably just picked up an easy 2” in just 30 minutes. I’ll have to check the gauge later. I saw this on HRRR last night, but it was supposed to fizzle out before it got here. Well that definitely didn’t happen lol
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Thursday briefing from Jeff:

Tropical moisture on the SSW flank of Gordon’s remains will be pushing into SE TX today and linger into the weekend and early next week while at the same time a weak frontal boundary moves into the area and stalls.

Remains of Gordon are over eastern AR this morning is tropical moisture along the coast and offshore starting to progress inland over the coastal counties with numerous showers and thunderstorms. A weak frontal boundary over the central plains ahead of a longwave trough over the western US will move ESE over the next few days, but eventually stall over the area. The combination of deep tropical moisture (PWS 2.2-2.4 inches) and lift from the incoming frontal zone/outflow boundaries will likely result in high rainfall coverage starting Friday and into early next week.

There does not at this time appear to be any significant feature to help concentrate heavy rainfall such as a short wave or defined low level boundary although one could argue the front could be a boundary if it remains defined. This should keep the risk of flooding rainfall on the low side, but isolated intense rainfall rates of 2-3 inches per hour will be possible under the heavier slow moving cells over the next few days which could lead to rapid street flooding.

Will need to keep an eye on rainfall trends for the next 3-4 days in the vent some sort of defined low level boundary becomes established over the region in a highly tropical air mass. As we saw earlier this week along Galveston and in San Antonio these tropical air masses can produce a lot of rainfall in a short period of time under the right conditions.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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jasons2k
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This morning: rain to my south
This afternoon: rain to my north

Story of my Texas life.
Cpv17
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jasons wrote:This morning: rain to my south
This afternoon: rain to my north

Story of my Texas life.
We’ve had 6.5” here in the past ten days including 2.5” today.
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