August 2020:

General Weather Discussions and Analysis
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tireman4
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Re: August 2020: Tracking Laura

Post by tireman4 » Fri Aug 28, 2020 4:09 pm

000
FXUS64 KHGX 282035
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
335 PM CDT Fri Aug 28 2020


.SHORT TERM [Tonight Through Tomorrow]...

A trough of low pressure persists across SE TX and this feature
coupled with high PW air has allowed for scattered showers and
thunderstorms to develop this afternoon. The GFS and HRRR continue
to be aggressive with shra/tsra this afternoon into the evening
while other models are more benign. The ingredients are in place so
will maintain chance PoPs through 01z and keep slt chance going over
the W-NW zones through 03z. Activity should begin to wane once
heating ends after sunset. Speaking of heat, 850 mb temps were very
warm and cloud cover/winds last night blunted any cooling and the
warm start has allowed temperature to reach the upper 90s by 1 PM.
Dew points are not mixing out and the heat/humidity combo is
producing oppressive and dangerous heat index values. Galveston
reached a heat index value of 110 degrees by 10 AM and 114 degrees
at 2 PM. Sugar Land reached a HI of 112 degrees by 2 PM and Angleton
reached 110. Will maintain the Heat Advisory through 10 PM but the
area should fall below criteria by around 800 PM.

There should be some clearing by mid evening but more clouds will
develop prior to sunrise and this coupled with winds not fully
decoupling will yield another night of very warm temperatures. It
will probably only cool into the upper 70`s inland and lower/mid 80s
toward the coast.

On Saturday, another warm start to the day and very warm
temperatures aloft will translate to another day with oppressive
heat. Have issued a Heat Advisory for Saturday as conditions look
rather similar to today with dew points struggling to mix out
coupled with warm daytime temperatures. Max Heat Index values will
again exceed 108 degrees by late morning at the coast and by early
afternoon further inland. Max Heat Index will range from 105 to 113
degrees. PW values drop considerably but briefly peak near 2.00
inches on Saturday afternoon. Could get a few showers and storms
late but most of the area will probably remain dry. 43


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

The forecast trend through the remainder of the weekend and into
the beginning of next week will continue to be characterized by
hot and humid conditions with potentially dangerous heat indices
along with scattered to isolated showers and thunderstorms. Upper
ridge will continue to build into the central CONUS by late
Saturday, while broad surface high pressure across the Gulf and
low pressures over the Rockies will promote low-level moisture
advection. Global models continue to indicate a surge of higher
(1.75-2.0+ in) PWs by Sunday evening, although ECMWF solution is
more aggressive than other sources. Regardless, values should
approach 90th percentile of observed climatology for nearby
sounding sites, particularly surrounding Galveston Bay. With
daytime highs expected to approach forecast sounding convective
temps across the area, conditions will remain favorable for the
development of diurnal showers and thunderstorms into the early
part of the week. With the surge of moisture expected to peak on
Monday, have included 40-50% PoPs. Daily activity should diminish
upon the loss of daytime heating.

We`re likely going to need to continue the Heat Advisories through
the weekend, with daytime highs not expected to budge from the mid
to upper 90s and maximum heat indicies remaining around 110
through Monday. Low temperatures, particularly along the coast,
will not exceed the low to mid 80s, near daily record values.
Given that these elevated nighttime low temperatures can
exacerbate heat stress experienced during the day, it will remain
imperative to take heat precautions in the coming days.

ECMWF/GFS have come into better agreement regarding the departure
of the prevailing ridge axis and approach of an upper trough as we
head into the middle of next week with GFS now favoring the
slower EC solution. A cold front extending from the associated
surface cyclone remains on track to approach the CWA on late
Tuesday/early Wednesday. Both solutions now show the surface
boundary pushing into the northern counties, though a prolonged
wind shift/temperature drop is not anticipated. Showers and
thunderstorms associated with the approaching front could impact
areas north of I-10 through Thursday. Have maintained slight-
chance PoPs for now given current uncertainty.

Cady

&&

.AVIATION [18Z TAF Issuance]...

Scattered showers and storms along the coast will expand inland
with heating. Will carry a VCTS for inland TAF sites through the
aftn. Conditions will settle down with the loss of heating after
sunset. NAM fcst soundings show some potential for MVFR cigs after
09z. Not terribly confident and went with scattered decks for now.
Looks considerably drier on Saturday with only isolated PoPs in
the afternoon but probabilities look too low to mention in TAFs.
Moderate SSW winds will become south and decrease later tonight
and should be lighter on Saturday. 43

&&

.MARINE...

Falling pressures in the lee of the Rockies and building surface
high pressure over the eastern Gulf of Mexico will allow for a
moderate onshore flow tonight. The flow will slacken early Saturday
and veer to the SW as low pressure scoots across the southern
plains. Winds will back to the SE as a weak sea breeze moves inland.
The pressure gradient tightens again Saturday night into Sunday with
onshore winds strengthening. A moderate to occasionally light
onshore flow will persist through Wednesday with a lighter winds
expected Thu/Fri as weak high pressure settles over the northern
Gulf of Mexico.

Re-issued a Coastal Flood Advisory for the bay facing shores of the
Bolivar peninsula. Water was reported on a few roads in Crystal
Beach. Overall, tides have returned to within a 1/2 foot of normal
values along the coast. 43

&&

.CLIMATE...

The day is not complete yet so this discussion is preliminary and
subject to change but the low temperature at GLS this morning was
only 86 degrees and this would tie for the all time warmest
overnight low temperature for this site (08/12/2020 and others). The
city of Houston recorded a low temperature of 83 degrees and this
would also tie for the warmest overnight low temperature for this
location (6/23/2019 and others). Late afternoon storms could bring
some rain cooled air so the low temps could change before the end of
the day. 43

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 77 101 77 100 79 / 20 10 0 10 0
Houston (IAH) 80 98 79 97 80 / 20 10 0 30 10
Galveston (GLS) 84 93 83 93 84 / 10 20 20 40 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...Heat Advisory until 10 PM CDT this evening for the following
zones: Austin...Brazoria
Islands...Brazos...Burleson...Chambers...Coastal
Brazoria...Coastal Galveston...Coastal Harris...Coastal
Jackson...Coastal Matagorda...Colorado...Fort
Bend...Galveston Island and Bolivar
Peninsula...Grimes...Houston...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Madison...Matagorda
Islands...Montgomery...Northern Liberty...Polk...San
Jacinto...Southern
Liberty...Trinity...Walker...Waller...Washington...Wharton.

Heat Advisory from 10 AM to 9 PM CDT Saturday for the following
zones: Austin...Brazoria
Islands...Brazos...Burleson...Chambers...Coastal
Brazoria...Coastal Galveston...Coastal Harris...Coastal
Jackson...Coastal Matagorda...Colorado...Fort
Bend...Galveston Island and Bolivar
Peninsula...Grimes...Houston...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Madison...Matagorda
Islands...Montgomery...Northern Liberty...Polk...San
Jacinto...Southern
Liberty...Trinity...Walker...Waller...Washington...Wharton.

Coastal Flood Advisory until midnight CDT tonight for the
following zones: Galveston Island and Bolivar Peninsula.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Coastal waters from
Freeport to Matagorda Ship Channel TX out 20 NM...Coastal
waters from High Island to Freeport TX out 20 NM...Waters
from Freeport to Matagorda Ship Channel TX from 20 to 60
NM...Waters from High Island to Freeport TX from 20 to 60
NM.


&&

$$

SHORT TERM...43
LONG TERM...Cady
AVIATION...43
MARINE...43

jabcwb2
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Re: August 2020: Tracking Laura

Post by jabcwb2 » Fri Aug 28, 2020 4:51 pm

Getting absolutely soaked in Tomball with rain and spinning winds. Looks so prett!!!

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Re: August 2020: Tracking Laura

Post by Cromagnum » Fri Aug 28, 2020 7:50 pm

Teased all day. Storms this morning missed south, then blew up just east. This evening everything to the north and passed south. Havent had a meaningful rain n weeks besides a quick quarter inch a couple weeks ago.

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Re: August 2020: Tracking Laura

Post by jasons2k » Fri Aug 28, 2020 8:14 pm

I got about 2 inches of rain today in a surprise storm. I needed it badly!

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tireman4
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Re: August 2020: Tracking Laura

Post by tireman4 » Fri Aug 28, 2020 10:49 pm

I got nuffin...LOL

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Re: August 2020: Tracking Laura

Post by tireman4 » Fri Aug 28, 2020 10:50 pm

000
FXUS64 KHGX 282354
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
654 PM CDT Fri Aug 28 2020

.AVIATION [00Z TAF Issuance]...

Some evening showers and thunderstorms scattered across the inland
flying areas are dissipating out now. By 01-02z, thunderstorms
activity may transition to some showers for a bit, but VFR
conditions will return across the TAF sites by 02z. Tonight may
bring in some lower ceilings but mostly looking borderline and
drier. Tomorrow will be VFR through the day with some chances of
afternoon convection but much lower chances than today. 35

&&

.SHORT TERM [Tonight Through Tomorrow]...

A trough of low pressure persists across SE TX and this feature
coupled with high PW air has allowed for scattered showers and
thunderstorms to develop this afternoon. The GFS and HRRR continue
to be aggressive with shra/tsra this afternoon into the evening
while other models are more benign. The ingredients are in place so
will maintain chance PoPs through 01z and keep slt chance going over
the W-NW zones through 03z. Activity should begin to wane once
heating ends after sunset. Speaking of heat, 850 mb temps were very
warm and cloud cover/winds last night blunted any cooling and the
warm start has allowed temperature to reach the upper 90s by 1 PM.
Dew points are not mixing out and the heat/humidity combo is
producing oppressive and dangerous heat index values. Galveston
reached a heat index value of 110 degrees by 10 AM and 114 degrees
at 2 PM. Sugar Land reached a HI of 112 degrees by 2 PM and Angleton
reached 110. Will maintain the Heat Advisory through 10 PM but the
area should fall below criteria by around 800 PM.

There should be some clearing by mid evening but more clouds will
develop prior to sunrise and this coupled with winds not fully
decoupling will yield another night of very warm temperatures. It
will probably only cool into the upper 70`s inland and lower/mid 80s
toward the coast.

On Saturday, another warm start to the day and very warm
temperatures aloft will translate to another day with oppressive
heat. Have issued a Heat Advisory for Saturday as conditions look
rather similar to today with dew points struggling to mix out
coupled with warm daytime temperatures. Max Heat Index values will
again exceed 108 degrees by late morning at the coast and by early
afternoon further inland. Max Heat Index will range from 105 to 113
degrees. PW values drop considerably but briefly peak near 2.00
inches on Saturday afternoon. Could get a few showers and storms
late but most of the area will probably remain dry. 43


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

The forecast trend through the remainder of the weekend and into
the beginning of next week will continue to be characterized by
hot and humid conditions with potentially dangerous heat indices
along with scattered to isolated showers and thunderstorms. Upper
ridge will continue to build into the central CONUS by late
Saturday, while broad surface high pressure across the Gulf and
low pressures over the Rockies will promote low-level moisture
advection. Global models continue to indicate a surge of higher
(1.75-2.0+ in) PWs by Sunday evening, although ECMWF solution is
more aggressive than other sources. Regardless, values should
approach 90th percentile of observed climatology for nearby
sounding sites, particularly surrounding Galveston Bay. With
daytime highs expected to approach forecast sounding convective
temps across the area, conditions will remain favorable for the
development of diurnal showers and thunderstorms into the early
part of the week. With the surge of moisture expected to peak on
Monday, have included 40-50% PoPs. Daily activity should diminish
upon the loss of daytime heating.

We`re likely going to need to continue the Heat Advisories through
the weekend, with daytime highs not expected to budge from the mid
to upper 90s and maximum heat indicies remaining around 110
through Monday. Low temperatures, particularly along the coast,
will not exceed the low to mid 80s, near daily record values.
Given that these elevated nighttime low temperatures can
exacerbate heat stress experienced during the day, it will remain
imperative to take heat precautions in the coming days.

ECMWF/GFS have come into better agreement regarding the departure
of the prevailing ridge axis and approach of an upper trough as we
head into the middle of next week with GFS now favoring the
slower EC solution. A cold front extending from the associated
surface cyclone remains on track to approach the CWA on late
Tuesday/early Wednesday. Both solutions now show the surface
boundary pushing into the northern counties, though a prolonged
wind shift/temperature drop is not anticipated. Showers and
thunderstorms associated with the approaching front could impact
areas north of I-10 through Thursday. Have maintained slight-
chance PoPs for now given current uncertainty.

Cady


.MARINE...

Falling pressures in the lee of the Rockies and building surface
high pressure over the eastern Gulf of Mexico will allow for a
moderate onshore flow tonight. The flow will slacken early Saturday
and veer to the SW as low pressure scoots across the southern
plains. Winds will back to the SE as a weak sea breeze moves inland.
The pressure gradient tightens again Saturday night into Sunday with
onshore winds strengthening. A moderate to occasionally light
onshore flow will persist through Wednesday with a lighter winds
expected Thu/Fri as weak high pressure settles over the northern
Gulf of Mexico.

Re-issued a Coastal Flood Advisory for the bay facing shores of the
Bolivar peninsula. Water was reported on a few roads in Crystal
Beach. Overall, tides have returned to within a 1/2 foot of normal
values along the coast. 43


.CLIMATE...

The day is not complete yet so this discussion is preliminary and
subject to change but the low temperature at GLS this morning was
only 86 degrees and this would tie for the all time warmest
overnight low temperature for this site (08/12/2020 and others). The
city of Houston recorded a low temperature of 83 degrees and this
would also tie for the warmest overnight low temperature for this
location (6/23/2019 and others). Late afternoon storms could bring
some rain cooled air so the low temps could change before the end of
the day. 43

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 77 101 77 100 79 / 20 10 0 10 0
Houston (IAH) 80 98 79 97 80 / 20 10 0 30 10
Galveston (GLS) 84 93 83 93 84 / 10 20 20 40 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...Heat Advisory until 10 PM CDT this evening for the following
zones: Austin...Brazoria
Islands...Brazos...Burleson...Chambers...Coastal
Brazoria...Coastal Galveston...Coastal Harris...Coastal
Jackson...Coastal Matagorda...Colorado...Fort
Bend...Galveston Island and Bolivar
Peninsula...Grimes...Houston...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Madison...Matagorda
Islands...Montgomery...Northern Liberty...Polk...San
Jacinto...Southern
Liberty...Trinity...Walker...Waller...Washington...Wharton.

Heat Advisory from 10 AM to 9 PM CDT Saturday for the following
zones: Austin...Brazoria
Islands...Brazos...Burleson...Chambers...Coastal
Brazoria...Coastal Galveston...Coastal Harris...Coastal
Jackson...Coastal Matagorda...Colorado...Fort
Bend...Galveston Island and Bolivar
Peninsula...Grimes...Houston...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Madison...Matagorda
Islands...Montgomery...Northern Liberty...Polk...San
Jacinto...Southern
Liberty...Trinity...Walker...Waller...Washington...Wharton.

Coastal Flood Advisory until midnight CDT tonight for the
following zones: Galveston Island and Bolivar Peninsula.

GM...None.

&&

$$

SHORT TERM...43
LONG TERM...Cady
AVIATION...35
MARINE...43

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Re: August 2020: Tracking Laura

Post by Cpv17 » Fri Aug 28, 2020 11:01 pm

I got nothing here. Haven’t had anything in a month now.

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tireman4
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Re: August 2020: Tracking Laura

Post by tireman4 » Sat Aug 29, 2020 6:56 am

000
FXUS64 KHGX 291210
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
710 AM CDT Sat Aug 29 2020

.AVIATION [12Z TAF ISSUANCE]...

Areas of patchy fog has develop across parts of the northern
counties early this morning, resulting in periods of MVFR-IFR
conditions. Fog is expected to lift and clear out by 15Z. S winds
will increase after 15Z to around 5-10 KTS and turn a little more
S-SE in the afternoon. Isolated to scattered showers may develop
along the local waters and coastal sectors this morning,
expanding northward into the central sectors in the afternoon.
MaxT will be in the mid 90s to low 100s and heat indicies look to
be around 108-114 deg F today. Activity is to dissipate in the
evening, and skies will lift and clear out tonight. Surge of
moisture along the waters may lead to periods of passing SH/TS and
could affect GLS/LBX from time to time early Sunday morning.
Activity is then expected to move northward and further inland
during the rest of the morning and afternoon hours. 24

&&

.PREV DISCUSSION... /ISSUED 613 AM CDT Sat Aug 29 2020/

SHORT TERM [Today through Sunday Afternoon]...

Chance for shower and thunderstorm development will be on the rise
this weekend, as a mid to upper level trough remains over LA region
and combines will a moist and unstable airmass along the surface.
Strong thunderstorms will be capable of producing frequent
lightning, gusty winds, and brief periods of heavy downpours.

For today, onshore flow transporting tropical moisture moving from
the Gulf will bump up the PWs into the 1.7 to 2.1 inch range. Expect
a few showers across the local Gulf waters to move into the coastal
regions from time to time early this morning. As the moisture
trickles north, showers and thunderstorms will transition into the
southern portions of the CWA and then expand a bit further into the
central portions by the afternoon hours. The highest PWs look to be
residing along the eastern half of the CWA...and this is where the
highest PoPs are currently. The moisture combined with temperatures
in the mid 90s to low 100s will lead to another day with heat
indicies of around 108-114 deg F. A Heat Advisory will be in effect
from 10 AM CDT to 9 PM CDT today. It is HIGHLY recommended to
practice Heat Safety if you plan to spend time in the outdoors
and/or in areas with poor ventilation. Dont forget your pets!
Surface temperatures could be well above these temperatures on
their tender paws.

Rain chances decrease during the evening and night hours as diurnal
heating decreases...but an even more impressive surge of tropical
moisture will make its way into the Gulf waters early Sunday
morning. This surge will slowly make its way across the coastal
locations during the morning hours and further northward during the
afternoon and will possibly tap into SB and MU CAPE of a little over
3,000 J/kg at around 21Z. Moreover, the upper level trough scoots a
bit further into the local area during the morning hours. Thus,
coverage of showers and thunderstorms is expected to be higher on
Sunday, and have thus added a little more PoPs for the day.
24

LONG TERM [Sunday Night Through Saturday]...
The deeper tropical moisture will spread further inland Sunday
night through Monday and 2-2.3" PW will be possible Monday so
expecting early morning showers in the Gulf and probably into the
coastal counties before sunrise...then expanding inland in the
morning and afternoon hours. Low level flow is stronger on Monday
and the seabreeze should penetrate well inland. Storms will again
be capable of brief heavy downpours, frequent lightning and gusty
winds. Tuesday should have a little less coverage as an upper
trough drops through the southern plains and the column warms and
dries out. The upper trough sets the stage for a cold front
Wednesday to push through North Texas and start to slow as it
nears SETX...greater rain chances should be over the NW portions
of the area with the GFS/ECMWF showing some nice bullseyes of
precipitation in the area or just northwest of the area. The front
or outflow looks to push south into the area Thursday night/Friday
and rain chances look greater as upper troughing rotates by to the
northeast. Having been burned on this a few times will be keeping
pops less than 50 percent even though some of the guidance is
higher.

Temperatures should start the period in the hot range and cool
down somewhat Tuesday into Wednesday with an increase in high
clouds along with the chance for showers and thunderstorms to
bring some relief as well. Temperatures could be below climo by
Friday or Saturday!
45

MARINE...

High pressure over the eastern Gulf of Mexico and low pressure in
the lee of the Rockies will maintain a moderate onshore flow through
the weekend. Moreover, shower and thunderstorm chances will be on
the rise this weekend, particularly Sunday, as deep tropical
moisture moves across the local Gulf waters. Moderate to
occasionally strong onshore winds is expected early next week
through mid week and will elevate seas to around 4-6 FT...Caution
Flags will likely be needed. Winds relax and seas decrease mid week
into the upcoming weekend. 24

CLIMATE...
Record high minimum temperature was set yesterday at
Galveston...85 degrees surpassing the 84 degree 1951 record.

Although it was hot across the area with CLL hitting the 103 mark
2011 was a scorcher on this date so the temperatures fell well
short of the records.

Today the record high minimum at Galveston in 84 degrees (1983)
may be in jeopardy.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 103 77 102 79 99 / 10 10 10 0 30
Houston (IAH) 99 80 97 81 95 / 30 20 30 10 40
Galveston (GLS) 93 83 94 84 92 / 30 30 40 20 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 10 AM this morning to 9 PM CDT this evening
for the following zones: Austin...Brazoria Islands...
Brazos...Burleson...Chambers...Coastal Brazoria...Coastal
Galveston...Coastal Harris...Coastal Jackson...Coastal
Matagorda...Colorado...Fort Bend...Galveston Island and
Bolivar Peninsula...Grimes...Houston...Inland Brazoria...
Inland Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Madison...Matagorda Islands...Montgomery...
Northern Liberty...Polk...San Jacinto...Southern Liberty...
Trinity...Walker...Waller...Washington...Wharton.

GM...NONE.
&&

$$

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DoctorMu
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Re: August 2020: Tracking Laura

Post by DoctorMu » Sat Aug 29, 2020 11:25 am

jasons2k wrote:
Fri Aug 28, 2020 8:14 pm
I got about 2 inches of rain today in a surprise storm. I needed it badly!
Got Lucy and footballed here. At least temperatures dropped 25 degrees from 103°F to 78°F! Today looks brutal.

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Re: August 2020: Tracking Laura

Post by Cromagnum » Sat Aug 29, 2020 12:23 pm

Hot is an understatement today

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