August 2017: Looking Back at Harvey 5 Year Later

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Ptarmigan
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August is coming up. August is when hurricane season starts to heat up.

Some of the most devastating hurricanes occurred in August; Sea Islands (1893), San Ciriaco (1899), Monterrey (1909), Camille (1969), David (1979), Alicia (1983), Andrew (1992), Charley (2004), Katrina (2005), Dean (2007), and Irene (2011).

There is also the August 21, 2017 Total Solar Eclipse.
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srainhoutx
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Hemispheric Indicators continue to strongly advertise a much more favorable pattern for Tropical Development in the Gulf of Mexico, Caribbean Sea and the Main Development Region in the North Atlantic Basin near the first of August and beyond.
The attachment 07252017 Mike Ventrice DFk5qHiXYAAI_oz.jpg is no longer available
Michael Ventrice‏Verified account @MJVentrice · 1h1 hour ago
Here we go! One of strongest CC atmos Kelvin waves of Summer is fcst to pass Atlantic in 1st wk of August. Watch for MDR TC outbreak 8/8-20

07252017  Mike Ventrice DFk5qHiXYAAI_oz.jpg
07252017 twc_globe_mjo_vp200.png
07252017 twc_mjoCCKW_vp200.png
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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srainhoutx
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I continue to see a significant Hemispheric Pattern Change as we start August and continue well into early September for our Region as well as the Tropics. A very strong Convectively Coupled Kelvin Wave (CCKW) near or slightly above 3.5 sigma above normal looks to near the Pacific Coast of Mexico and extend into the far Western Atlantic Basin as we begin August. The CCKW will continue to extend East into the Caribbean Sea and the Main Development Region (MDR) during the second week of August. There are growing indications that the Madden Julian Oscillation will become more favorable as it shifts toward Phase 8 that would coincide with the Pattern Change.
07262017 twc_mjoCCKW_vp200.png
07262017 twc_globe_mjo_vp200.png
Interestingly the Updated Climate Prediction Center Day 6 to 10 and Day 8 to 14 Outlooks suggest below normal temperatures likely due to increasing cloudiness and precipitation developing across Texas. The Precipitation Outlook for the above mention extended range outlooks is also above normal. Time to start paying a bit more attention to our sensible weather, particularly the Tropic. It tis that time of year after all... ;)
07252017 610temp_new.gif
07252017 610prcp_new.gif
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Music to my ears!!!! :D
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srainhoutx
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We have been monitoring the potential for a Major shift in the Hemispheric Pattern and the trends that we began seeing back in mid July look likely to come to fruition. An unusually strong Convectively Coupled Kelvin Wave (CCKW) which assists in a rising motion in the Atmosphere which allows the up growth of Tropical Thunderstorms is heading our way next week in conjunction with favorable Madden Julian Oscillation (MJO) which also indicates rising air that provides another clue of much more favorable conditions for Tropical Development. While we do not know exactly where, when and if any tropical mischief will form, the Atmospheric conditions appear to be much more favorable for potential Tropical Development across the Atlantic Basin.

Michael Ventrice‏Verified account @MJVentrice · 1h1 hour ago
A very strong CC Kelvin wave (contours) will pass the Atlantic next week, transitioning the active MJO phase (blue shading) o/W. Hemisphere
07272017 Mke Ventrice DFvLVeiXkAEXSRe.jpg
The Ensembles are beginning to suggest the potential for TC Genesis somewhere across the Main Development Region, so an eye on the Tropics is warranted.

Also, the Climate Prediction Center Day 6 to 10 Outlook advertises below normal Temperatures and above normal Precipitation across our Region.
07262017 610temp_new.gif
07262017 610prcp_new.gif
CPC Day 8 to 14 Outlook:
07262017 814temp_new.gif
07262017 814prcp_new.gif
One thing we are monitoring for next week as we begin August is a stalled frontal boundary along the Gulf Coast which raises an eye in early August, particularly when we see all the parameters coming together suggesting an active and conducive weather pattern emerging. We will also need to monitor for Convective Complexes rolling South and East with a NW flow aloft as that big Heat Ridge shifts West putting us on the favorable side of the 'Ring of Fire'.
07272017 5dayfcst_wbg_conus.gif
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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srainhoutx wrote:I continue to see a significant Hemispheric Pattern Change as we start August and continue well into early September for our Region as well as the Tropics. A very strong Convectively Coupled Kelvin Wave (CCKW) near or slightly above 3.5 sigma above normal looks to near the Pacific Coast of Mexico and extend into the far Western Atlantic Basin as we begin August. The CCKW will continue to extend East into the Caribbean Sea and the Main Development Region (MDR) during the second week of August. There are growing indications that the Madden Julian Oscillation will become more favorable as it shifts toward Phase 8 that would coincide with the Pattern Change.
07262017 twc_mjoCCKW_vp200.png
07262017 twc_globe_mjo_vp200.png
Interestingly the Updated Climate Prediction Center Day 6 to 10 and Day 8 to 14 Outlooks suggest below normal temperatures likely due to increasing cloudiness and precipitation developing across Texas. The Precipitation Outlook for the above mention extended range outlooks is also above normal. Time to start paying a bit more attention to our sensible weather, particularly the Tropic. It tis that time of year after all... ;)
07252017 610temp_new.gif
07252017 610prcp_new.gif
That looks pretty sweet right there. I'll take it!
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srainhoutx
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One more piece of the puzzle we are watching regarding the Hemispheric Pattern Change and its potential impacts regarding Tropical Development, the 00Z ECMWF EPS and its individual ensemble members suggest High Pressure remains in control of the steering flow (shown in the Red shades) and areas of Lower Pressure (shown in Blue shades) extend into the Bahamas, Western Caribbean Sea as well as the Gulf.
07292017 Mike Ventrice DF5stT5XgAA6wTp.jpg
Michael Ventrice‏Verified account @MJVentrice · 59m59 minutes ago

Early 11-15d period is looking very interesting with regards to tropical cyclone U.S. impact risk; Atlantic ridge extension into east U.S...
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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srainhoutx wrote:One more piece of the puzzle we are watching regarding the Hemispheric Pattern Change and its potential impacts regarding Tropical Development, the 00Z ECMWF EPS and its individual ensemble members suggest High Pressure remains in control of the steering flow (shown in the Red shades) and areas of Lower Pressure (shown in Blue shades) extend into the Bahamas, Western Caribbean Sea as well as the Gulf.
07292017 Mike Ventrice DF5stT5XgAA6wTp.jpg
Michael Ventrice‏Verified account @MJVentrice · 59m59 minutes ago

Early 11-15d period is looking very interesting with regards to tropical cyclone U.S. impact risk; Atlantic ridge extension into east U.S...
Interesting. The Death Ridge in appears to be weak in Texas in the early part of August. That weakness we've seen on an off all summer between the ridges persists. Be prepared just in case...
Last edited by DoctorMu on Sun Jul 30, 2017 1:32 pm, edited 1 time in total.
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srainhoutx
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IF the overnight ECMWF and GFS are correct, a unusually strong Summer Cold Front drops South through the Plains into our Region next weekend. Instead of daytime highs in the low 100's like yesterday, we could see Highs in the low 80's and morning lows in at least the low 70's.
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srainhoutx wrote:IF the overnight ECMWF and GFS are correct, a unusually strong Summer Cold Front drops South through the Plains into our Region next weekend. Instead of daytime highs in the low 100's like yesterday, we could see Highs in the low 80's and morning lows in at least the low 70's.
That would be awesome IF that happens. Keeping my fingers crossed. :D
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srainhoutx wrote:IF the overnight ECMWF and GFS are correct, a unusually strong Summer Cold Front drops South through the Plains into our Region next weekend. Instead of daytime highs in the low 100's like yesterday, we could see Highs in the low 80's and morning lows in at least the low 70's.
Still there on the 12Z on the Euro, GFS, and Ensemble. I sure hope that Lucy doesn't pull the football away. Yesterday's heat turned part of the lawn to straw in a day. Cinch bugs are feasting. Heavy watering last night and triazanon today. Ironically, the more "normal" summer had not "toughened up" the grass yet. At least St. Augustine eventually grows back.

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07312017 Mike Ventrice DGDqpPTXYAE2OXV.jpg
Michael Ventrice‏Verified account @MJVentrice · 2h2 hours ago
Once our strong Kelvin wave passes the Atlantic, we are seeing two risk zones... one o/the Gulf of Mexico and the other o/the MDR next week.
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tireman4
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Oh my


945
FXUS64 KHGX 310935
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
435 AM CDT Mon Jul 31 2017

.DISCUSSION...
Frontal boundary continues to make slow, but steady progress
across southwest zones early this morning. A thin band of shra/tstms
has once again developed along the windshift. Other than a few
lingering shra, most of this activity should be sw of the CWA and
in the Gulf by early to mid morning. Daytime highs today should
still be close to normal, but humidities will be lower than what
most are used to this time of year.

GOES-16 derived PW loop shows a tongue of higher moisture levels
situated along and south of the cntl La coast. Model guidance
depicts this making its way into the upper Tx coastal waters later
tonight and eventually inland Tue morning along with some associated
sct precip. Went ahead and nudged POPs up a touch south of I-10.

No significant changes to the ongoing forecast during the mid/late
week time period. Upper ridge is still expected to retreat westward
allowing a large broad trof to take shape over the eastern half
of the country. Locally, the weak surface front washes out and
deeper Gulf moisture will continue filtering back into the region
and bring a period of unsettled wx going into the weekend. Chances
of precip can be expected daily, esp across the southern 2/3 of
the region. It`ll probably follow a typical diurnal trend with
late night and morning activity near the coast spreading inland
during the day. However, there will also be some subtle,
hard-to-time disturbances embedded in the NW flow aloft to keep
an eye on as well. Medium range solns still bring a front close
to se Tx late Fri night. 47

.TROPICAL...
As just noted by NHC, Tropical Depression Six has formed in the
Gulf of Mexico about 75 miles west of Tampa Florida early this
morning. It should, in general, track eastward and is not expected
to bring any impacts to the upper Texas coast. 47

&&

.MARINE...
Light to moderate NE winds are expected to prevail across the bays
and coastal waters today through tomorrow. These slightly elevated
winds/seas (mainly over Galveston bay/nearshore waters) should re-
main just under Caution criteria. High pressure lingering over the
northern MS river valley will help keep these generally light E/NE
winds in the forecast through at least late Tue. As the high moves
off further east...light SE winds are forecast to return by Weds.
Otherwise a series of weak upper level disturbances moving in from
NW during the remainder of the week and then a possible cold front
approaching this upcoming weekend will help produce periods of un-
settled weather across the marine waters these next several days.
41

&&

.AVIATION...
Generally VFR conditions expected as light NE winds prevail in the
wake of the cold front. This slightly drier airmass is forecast to
remain in place through late Tue. Of minor concern are the SH/TSRA
still forming along this boundary itself as it slowly moves across
the far SW portions of the CWA. Given the prevailing upper pattern
not expecting this line to regress back into SE TX at this time. 41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 96 74 95 75 91 / 0 0 10 20 40
Houston (IAH) 94 75 93 76 89 / 0 0 30 20 50
Galveston (GLS) 91 81 88 80 87 / 0 30 40 40 50

&&

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

&&

$$
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Emily made landfall on Anna Maria Island as a weak TS.

I spent last week at Indian Rocks Beach and the weather was beautiful.
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A few showers and an isolated thundershowers are moving toward the Upper TX Coast across the NW GOM this morning. This is a sign of the GOM moisture return which will bring increasing rain chances though the rest of the week and through the upcoming weekend.
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The overnight guidance continues to advertise a cold front sagging South toward the Gulf Coast on Friday before pulling up stationary suggesting a prolonged period of unsettled weather as disturbances drop South from the Central Plains around the retreating Western Heat Ridge and abundant tropical moisture increasing with an onshore low level flow off the Gulf
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There is the mention of those two words again...music to my ears in August.



000
FXUS64 KHGX 011131
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
631 AM CDT Tue Aug 1 2017

.DISCUSSION...
12Z Aviation...A few SHRA near the coast early this am. Expect
scattered SHRA to move inland a little later this morning. Do not
think we will see many if any SHRA as far inland as CXO this
afternoon. Expect more coverage tomorrow than what we see today.
NE winds will become SE later this afternoon, generally in the 5
to 10 KT range. 33

&&

.PREV DISCUSSION... /ISSUED 505 AM CDT Tue Aug 1 2017/

DISCUSSION...
Looks like an increasingly wet start for the week...with more wet
weather likely through much of this forecast. The isolated/widely
scattered activity currently over the coastal waters should cont-
inue to move into SE TX this morning and afternoon. The best rain
chances will remain along the coast, extending inland generally S
of I-10. The increased cloud cover will also help keep temps near
normal levels today.

Models keeping this upcoming forecast a wet one given the progged
pattern aloft. The building ridge off the U.S. west coast will be
producing a corresponding upper trough across the MS river valley
the next few days. The increasingly NW flow aloft will be drawing
a series of weak disturbances down into the area from the Central
Plains. This combined with the return of onshore winds and deeper
Gulf moisture appear to be setting the stage for scattered storms
these next few days. The elevated rain chances will remain in the
forecast through the weekend as another cold front approaches and
then stalls across the region.
41

MARINE...
Light to moderate easterly winds are expected today, becoming
southeast tonight. By mid-week we will see a weak gradient and
lighter and more variable winds as a weak cool front approaches and
weakens near the coast. Chances for showers and thunderstorms will
increase on Wed and continue through the weekend as a series of
upper level disturbances move across the area. Southerly winds and
seas are likely to increase slightly late next weekend. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 96 75 91 74 92 / 10 20 40 30 30
Houston (IAH) 92 74 89 74 89 / 20 20 60 40 50
Galveston (GLS) 88 79 87 78 87 / 40 30 50 50 50

&&

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

$$

Discussion...99
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That's a beautiful rainfall map!
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Weak low is present in the central Gulf. Would go with 20% chance of development. Surprised Stacy Stewart didn't mention it in today's outlook, given what we just went through with Emily. Not much model support, but we have to keep a close eye on ANY such features in August/September. It will be moving northeast-east, not toward Texas.

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srainhoutx wrote:The overnight guidance continues to advertise a cold front sagging South toward the Gulf Coast on Friday before pulling up stationary suggesting a prolonged period of unsettled weather as disturbances drop South from the Central Plains around the retreating Western Heat Ridge and abundant tropical moisture increasing with an onshore low level flow off the Gulf

A rarely seen precip prediction map in August in Texas without a discrete tropical system at play.
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