July 2020

General Weather Discussions and Analysis
Cpv17
Posts: 1452
Joined: Fri Aug 31, 2018 12:58 pm
Location: El Campo/Wharton
Contact:

Re: July 2020

Post by Cpv17 » Wed Jul 29, 2020 4:17 pm

Just got home from work and checked the gauge. Ended up with a quarter inch today bringing my total to 4.55” since last Wednesday.

unome
Posts: 3037
Joined: Fri Feb 12, 2010 6:11 pm
Location: Cypress

Re: July 2020

Post by unome » Wed Jul 29, 2020 6:29 pm


Cpv17
Posts: 1452
Joined: Fri Aug 31, 2018 12:58 pm
Location: El Campo/Wharton
Contact:

Re: July 2020

Post by Cpv17 » Thu Jul 30, 2020 8:45 am

Well guys it looks like we’ll be back in the oven for a couple days. Rain comes back Saturday.

User avatar
jasons2k
Posts: 3171
Joined: Thu Feb 04, 2010 12:54 pm
Location: Imperial Oaks
Contact:

Re: July 2020

Post by jasons2k » Thu Jul 30, 2020 3:35 pm

I expected today to be a little drier but wow. The radar shows nothing.

User avatar
DoctorMu
Posts: 2383
Joined: Sun Jun 28, 2015 10:58 am
Location: College Station
Contact:

Re: July 2020

Post by DoctorMu » Fri Jul 31, 2020 12:11 am

50% chance on NOAA
80% TWC for rain chances tomorrow. surprising.

GFS did sniff this front out over a week ago IIRC.

Pops have been increased since pm disco.

PREV DISCUSSION... /ISSUED 348 PM CDT Thu Jul 30 2020/

DISCUSSION...

Today has been warmer and drier than past days as we see a short
break in our recent active weather pattern in Southeast Texas. The
emphasis there should be on short, as a weak cold front looks to
sag southward towards our area later tomorrow. It could be as
early as mid-day Friday that we start to see rain and storms
on/ahead of this front start to push in from the north, but things
will probably hold off until late Friday afternoon or Friday
evening. If the front remains strong enough and/or the timing with
daily heating is right, some storms north of Houston could be
strong, with a severe storm or two in the mix.

The front will continue to sag southward on Saturday before
washing out, but continued active weather is likely to persist
into the first half of next week. As next week grows older,
eventually an upper ridge will build in from the west, giving us a
trend towards higher temperatures and less rain.

SHORT TERM [Friday Through Saturday Night]...

The radar, satellite, and well, the window appear noticeably
different from recent days. Though the cloud streets over much of
Southeast Texas indicate at least a little bit of low level
instability, especially paired with the small, isolated showers
here and there. However, this instability is definitely disrupted,
given that the cloud streets have never really been continuous,
and the day cloud phase RGB satellite imagery shows that even when
showers develop, we are not seeing deep, sustained convection to
kick off more significant clusters of storms.

With the decreased cloudiness and rain, temperatures have also
risen higher. We`ve still got an hour or two left of decent
insolation, so while there`s still a short window left for further
convection, things should start to wind down in not too long, with
clouds dissipating this evening. We should continue to look for
the typical nocturnal development of low clouds closer to dawn,
and while we might see some streamer showers as well, GOES
precipitable water at the coast is relatively low.

The big question for tomorrow is...what does the incoming front
from the north mean for us? Given that this is a fairly
unseasonable event, things are going to depend very strongly on
just how strong this front holds, and the timing of when it
arrives. Also, assuming some organized convection develops in
North Texas on the front, how does that cluster`s cold pool impact
things? Because of this, uncertainty is greater than typical for a
front, and thus...I`m likely to be a little more hand-wavy than
usual here, as the skill in forecasting important mesoscale
details is just not really there right now.

Amongst the deterministic guidance, the GFS is probably fastest
and strongest, pushing farther, lasting longer before washing out,
and generating the most widespread precip. The Euro is a bit
weaker and maybe a little slower. The NAM is slowest and gives us
the least coverage in rain, but does generate higher amounts in
convection where it does fire. Usually I kind of like the NAM,
just because its greater vertical resolution helps it handle
shallower cold fronts better than the globals. But...if we do see
a linear convective system on the front, it`s cold pool should
enhance that boundary, which I would think would happen if the NAM
bursts strong convection. Ultimately, the difference is not huge,
so the official forecast is roughly a multi-model ensemble mean,
with PoPs beginning to perk up in Houston county as early as mid-
day tomorrow, but not really showing strong likelihood for rain
until the late afternoon and evening.

Though the greater severe threat is likely north of our area, the
environment should be unstable enough to delay the degradation of
any strong convective system and provide a marginal threat for
damaging winds or even some small hail north of Houston. Those
winds, as well as periods of heavy rain, are expected to be the
main threats. But as we head into the overnight hours...there will
some decrease in activity with loss of heating and other
stabilizing factors.

LONG TERM [Sunday Through Thursday]...

Still not a lot of consensus on how far south this line will
slide before stalling, but will keep with the previous trend with
higher POPs generally along and south of I-10 during the day on
Sat. Rain chances should be moderating a bit by Sun as this
surface boundary continues to weaken and the slightly drier air
filters further down the CWFA toward the coast. With the upper
trof axis lingering over the region into the start of next week,
it`s hard to argue against the idea of additional shortwaves
moving in from the N/NW for that time frame. While timing is going
to be the main issue, the better chances should be during the day
Mon/Tue with heating and whatnot. Did keep with the previous
thinking of tapering POPs even lower by the middle of next week as
long-range guidance is hinting that the upper ridge is set to
begin building into the state from the west.

MARINE...

Onshore flow tonight looks to be less intense as high pressure
ridges into the area. A weak boundary is expecting to advect into
the region starting Friday night but not looking at the coastal
waters being effected until late Saturday, with winds becoming more
westerly. Evening onshore flow will be slight if any, but is
expecting to return Tuesday evening with high pressure in the gulf.
Seas begin at 2-3ft and subside into the weekend down to 2ft in the
coastal and offshore waters. By Tuesday, seas subside even more to
only 1-2ft.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 76 97 75 96 74 / 10 40 40 20 10
Houston (IAH) 78 95 78 93 78 / 10 30 40 40 20
Galveston (GLS) 82 91 80 91 80 / 10 10 30 40 30

User avatar
tireman4
Global Moderator
Global Moderator
Posts: 2947
Joined: Wed Feb 03, 2010 9:24 pm
Location: Humble, Texas
Contact:

Re: July 2020

Post by tireman4 » Fri Jul 31, 2020 9:16 am

000
FXUS64 KHGX 311152
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
652 AM CDT Fri Jul 31 2020

.AVIATION [12Z TAF Issuance]...

The IFR ceilings that CLL and UTS and MVFR ceilings at CXO down
the HOU will scattered out by mid morning with VFR ceilings
continuing through the day. A line of showers and thunderstorms is
expected to push through the region this afternoon bringing VCTS
to TAF sites through this evening. Then a second line of showers
and thunderstorms will move through this evening and overnight
thats associated with a weak cold front. Winds will become
northerly with the frontal passage. MVFR CIGs will again be
possible tonight, but then VFR conditions expected during the day
tomorrow.

Fowler

&&

.PREV DISCUSSION /Issued 421 AM CDT Fri Jul 31 2020/...

.SHORT TERM [Tonight Through Sunday]...

As of 4AM, a weak cold front is located along the TX/OK border
that is producing some showers and thunderstorms north of DFW.
Outflow from these storms may trigger some light rain showers in
Houston, Madison, and Trinity counties by sunrise. The front
located to the north will be making its way southward through the
day today bringing us a chance of thunderstorms - with the
potential for some stronger thunderstorms. The front is expected
to reach the northern counties in the late morning, then slowly
make its way towards I-10 by the mid afternoon to evening. It will
continue to move its way towards the coast overnight, but it will
weaken even further as it does so. The thunderstorms will have
some fuel to work with this afternoon as CAPE values will be in
the 2000 to 3000 J/kg range with 0-3 km lapse rates of around 6 to
7 C/km. While not the most conductive set up for strong to severe
thunderstorms, there may be some isolated strong thunderstorms
this afternoon producing some strong gusts. The SPC has basically
everything north of I-10 in a Marginal Risk for Severe
thunderstorms this afternoon. The threat diminishes south of I-10
because of the weakening front, and because by the time its there
the sun has set and the lack of daytime heating will limit
thunderstorm development. Overnight tonight, there may be some
lingering showers and thunderstorms over the coastal counties, but
overall most of the precipitation will be off the coast.

This front is expected to stall over the northern Gulf coast on
Saturday, but guidance has it very weak and barely existent over
SE Texas. So, expect mainly diurnally driven showers and
thunderstorms through the weekend with the higher chances near the
coast where that boundary may provide a little bit extra lift.
Shower activity on Sunday is expected to be very isolated as high
pressure begins to build across the Gulf.

Temperatures through the short term will be fairly consistent.
Highs in the afternoons in the mid to upper 90s inland and upper
80s to low 90s along the coast. BCS area on Sunday may get into
the triple digits as higher heights begin to stretch into the
area. Lows temperatures through the weekend will be in the mid to
upper 70s.

Fowler


.LONG TERM [Sunday Night Through Friday]...

A broad long wave trough over the Great Lakes will extend into Texas
through Tuesday. A weak upper level disturbance will slide into the
state on Monday and could bring scattered showers and thunderstorms
to the area on Monday afternoon. At the surface, a weak cold front
will move into North Texas and slowly move into SE TX pulling up
stationary over the area (near I-10). The front will likely serve as
a focus for isolated to scattered showers and thunderstorms on
Tuesday. Some differences between the GFS and the EC as the the
ECMWF is deeper with the upper trough and further south with the sfc
front. Have leaned toward the EC as it is supported by the Canadian
model.

The upper level trough begins to shift east on Tuesday as an upper
level ridge over the southern Rockies amplifies and expands into
West Texas. The upper ridge will be centered over West Texas by
Thursday morning but 500 mb heights only build to around 592 dm.
Ridging should suppress rain chances toward the end of the week but
the minimally higher heights don`t support a huge warm up. Will keep
MaxT values in the mid/upper 90`s. Drier air aloft will mix to the
surface each afternoon so heat index values look modest rising to
between 98-103 degrees each afternoon. 43


.MARINE...

Expect light onshore flow through the day today with some isolated
streamer showers in the morning hours. A weak cold front will move
into the Gulf waters overnight tonight bringing increased chances of
showers and thunderstorms, but the front is expected to be very weak
by the time it gets to the Gulf. Because of this, there will not be
a strong wind shift with the boundary passage. The boundary is
expected to stall over the Gulf waters through the day on Saturday
continuing the higher chances of precipitation.

High pressure builds in over the northern Gulf on Sunday and it will
remain through the week. So, expected continued onshore flow, low
seas, and low chance of precipitation through the week.

Fowler

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 95 75 96 74 98 / 40 30 20 10 20
Houston (IAH) 95 77 94 77 96 / 20 40 40 20 30
Galveston (GLS) 89 80 89 81 92 / 10 40 40 20 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

User avatar
jasons2k
Posts: 3171
Joined: Thu Feb 04, 2010 12:54 pm
Location: Imperial Oaks
Contact:

Re: July 2020

Post by jasons2k » Fri Jul 31, 2020 12:40 pm

Well it’s 97F here with a dew point of 77F. Surely that’s enough energy to get things cranking later on.

User avatar
jasons2k
Posts: 3171
Joined: Thu Feb 04, 2010 12:54 pm
Location: Imperial Oaks
Contact:

Re: July 2020

Post by jasons2k » Fri Jul 31, 2020 1:10 pm

The Strom Radar app’s future radar (maybe it’s the HRRR ?) shows a big blowup, ahead of the front, right over Montgomery County around 4pm and pushes it into Harris County and then brings a second round down with the front towards midnight.

User avatar
jasons2k
Posts: 3171
Joined: Thu Feb 04, 2010 12:54 pm
Location: Imperial Oaks
Contact:

Re: July 2020

Post by jasons2k » Fri Jul 31, 2020 3:02 pm

How is the middle of that line weakening as it heads this way? How the heck and why? We are at peak heating. No pesky outflow outrunning the convection (yet). That line should be filling-in right now, not falling apart. 🤦‍♂️

redneckweather
Posts: 838
Joined: Mon Feb 08, 2010 7:29 pm
Location: Montgomery, Texas
Contact:

Re: July 2020

Post by redneckweather » Fri Jul 31, 2020 3:20 pm

Just like it's been doing to me in my neck of the woods for a solid week. Gets close then poof.

Post Reply