April 2017 - MS 150 Forecast This Weekend

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wxman57
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Once again, for the third year in a row, the MS 150 bike ride from Houston to Austin may be plagued by a line of heavy to severe thunderstorms. Latest GFS indicates that the line of showers/storms will impact the La Grange overnight rest stop Saturday night. The rain could be over with by the time the ride resumes on Sunday morning, but watch for Sunday's temperatures to be 10-15 degrees cooler than Saturday.
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Katdaddy
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A significant severe weather event is likely across the ARKLATEX with Moderate Risk area. An Enhanced Risk area stretches from NE TX to S MO.

The temperature roller coaster continues. A few light showers will be possible across SE TX today with very warm temps that may reach 90F. This evenings front will drop overnight lows down to the upper 40s well inland to 50s across Houston metro. A few thunderstorms will be possible if the cap weakens late this afternoon as the front moves across the area. Areas NE of Houston metro have the best chance of some strong to severe storms if the cap weakens with a Marginal Risk area.

A quick rebound from a cool Thursday morning into the upper 70s and 80 with return flow beginning. The onshore flow increases Friday with temps possible reaching 90F.
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srainhoutx
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Wednesday morning briefing from Jeff:

A strong storm system will approach SE TX this weekend.

Cold front currently moving into N TX will progress southward today and across SE TX this afternoon. Ahead of the boundary SW flow at the surface will push temperatures well into the 80’s and possibly near 90 before the front arrives. Area is strongly capped this morning and even with the tail end of a short wave and lift along the front, do not think the cap will be overcome for most of the area. Capping will be weakest from roughly College Station to Chambers County and areas NE of that line may see an isolated strong thunderstorms with the front this afternoon.

Much cooler and drier on Thursday, but this will be short lived as the next system rapidly approaches from the west. Low level southerly flow begins in earnest late Thursday and increases on Friday helping to transport and tropical air mass northward into east TX. Approaching strong short wave will deepen into a closed upper level low over the SW US early Saturday and barrel into TX late Saturday into Sunday. Expect strong moisture advection on Saturday to promote scattered showers and even a few thunderstorms be the afternoon hours.

Main event will arrive into the region Saturday night into midday Sunday with strong forcing aloft helping to erode capping allowing deep convection to develop. Instability and shear values look favorable for strong to severe thunderstorms and PWS rise to near 2.0 inches by Saturday evening which will support a heavy rainfall threat. SPC has areas just to our north outlooked for severe weather this weekend and will need to watch trends to see if this needs to be expanded southward which appears possible depending on mid level capping.

As for rainfall widespread 1-2 inches will be possible this weekend with the greatest chances along and NE of a line from Bastrop to Sugar Land to Galveston. Could certainly see some isolated higher totals with PWS so high, but the system currently looks progress enough to keep things manageable over the region.
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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695
FXUS64 KHGX 261736
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1236 PM CDT Wed Apr 26 2017

.AVIATION...
Light SHRAs with the pre-frontal trof have moved off the coast at
present...and keeping an eye to our N/NE with the development at/
along the cold front itself. Still banking on the strong cap over
the region to keep any additional precipitation out with FROPA it-
self and main change with the 18Z TAFS was to tweak the timing of
the front. Otherwise, quite a bit of haze lingering across the FA
in the wake of the pre-frontal trof with some spots of MVFR CIGS.
All of this should clear out behind the front with VFR conditions
areawide this evening/overnight/most of tomorrow. 41

&&

.PREV DISCUSSION... /ISSUED 1027 AM CDT Wed Apr 26 2017/

UPDATE...
The previous forecast appears to be on track. We currently have a
few warm air advection showers pushing through parts of SE Texas
this morning. 12Z soundings from CRP and LCH showed a very strong
cap in place. I have some doubts as to how much of the cap will
really be able to erode by this afternoon when the approaching
front pushes into our area. The best chance for breaking the cap
and therefore getting thunderstorms will be generally to the
northeast, or across the Piney Woods region. If we are able to
break through the cap, steep mid level lapse rates of around
7.5-8.0 and forecast CAPE over 3000 will give any thunderstorms
that do develop the potential to pack some damaging winds and
large hail. The tornado threat is also nonzero and something to
monitor, but for now the greatest threats appear to be damaging
winds and hail. 11

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 86 51 84 67 90 / 20 0 0 10 10
Houston (IAH) 89 56 84 69 90 / 20 10 0 10 10
Galveston (GLS) 84 64 78 74 82 / 20 10 0 10 10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Coastal waters from
Freeport to the Matagorda Ship Channel out 20 NM...Coastal
waters from High Island to Freeport out 20 NM...Galveston
Bay...Matagorda Bay.

Small Craft Advisory until 4 PM CDT this afternoon for the
following zones: Waters from Freeport to the Matagorda Ship
Channel from 20 to 60 NM...Waters from High Island to
Freeport from 20 to 60 NM.

&&

$$
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Katdaddy
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Temps mostly in the 50s across SE TX with some upper 40s well inland and a few 60s along the coast. A beautiful day with warming temps into the low 80s this afternoon. Increasing GOM moisture and very warm temps up to 90F on Friday. Severe thunderstorms and locally heavy rain will be possible across SE TX late Saturday night and early Sunday morning. The SPC has most of SE TX in a Slight Risk area.
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Katdaddy
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High temps in the upper 80s and low 90s across SE TX this afternoon with increasing moisture and gusty S winds. A Coastal Flood Watch has been issued for the Upper TX Coast Saturday due to near gale force onshore winds, long swells, and high surf. Water levels could reach 3.8ft or higher resulting low lying coastal flooding. Saturday the MS-150 will experience cross winds gusting to 30MPH on the way to La Grange with showers and isolated thunderstorm possible.

A potentially stormy Saturday night and early Sunday morning for SE TX. The SPC has a large Enhanced and Slight Risk areas across, N, S Central, SE, and E TX. Locally heavy rain will also be a possible.
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tireman4
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It will be warm out there folks. Stay hydrated.


000
FXUS64 KHGX 281121
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
621 AM CDT Fri Apr 28 2017

.AVIATION...
Main issues this morning will be timing of the MVFR conditions
lifting to VFR and an increase in the wind speeds. Should see
winds increasing before or as the ceilings lift. Patchy fog or
haze possible at the coast. During the late morning and afternoon
winds will become gusty. Tonight the winds will stay up even as
the ceilings once again lower to MVFR. At the coast and near
Galveston Bay winds may gust to 25 to 30 knots. Overnight tonight
wind gusts to near 34 knots are possible at KGLS.

40

&&

.PREV DISCUSSION... /ISSUED 408 AM CDT Fri Apr 28 2017/

DISCUSSION...
At 100 AM, an area of low pressure was located over west Texas
with a dry line extending from about Lubbock to Ft Stockton. The
pressure gradient across east Texas was tightening in response to
the deepening area of low pressure out west. South winds will
strengthen throughout the day and breezy conditions will prevail
by afternoon. High temperatures today are conditional on when the
clouds break and the amount of mixing produced by sfc winds. 850
temps are progged to reach 25 C this afternoon and bringing these
values down to the sfc dry adiabatically will produce sfc temps
between 98-100. Clouds for the first half of the day should moderate
temps a bit but once sunshine returns in the aftn, feel temps could
rise pretty quick. Heat index values will climb today and will
probably top out in the upper 90s this afternoon. It will feel
more like summer today. Min temps tonight should remain very warm
with clouds filling back in during the evening to help insulate.
Winds will remain strong so mixing will also keep temps from
falling much. Would not be surprised if a few locations remained
near or above 80 degrees overnight.

The strong winds will also produce elevated tides late tonight. Water
levels could reach values between 3.5 and 4.0 feet and this would produce
some flooding along the coast, especially along the Bolivar peninsula. A
coastal flood watch has been issued for late tonight through
Saturday with the best window for coastal flooding around sunrise
Saturday.

Saturday will remain warm with high temps warming into the
mid/upper 80s. Could get a few showers beneath a strong capping
inversion Saturday morning as the low level jet nears the
area. There could be some aftn convection as strong capping in
the morning gradually weakens, PW values climb to 1.90 inches and
convective temps drop into the mid 80`s.

Strong thunderstorms are expected to move across SE TX Saturday
night. SPC has outlooked much of the region in Slight or Enhanced
Risk for Saturday night. CAPE values will 3000 J/Kg, LI values
between -9 and -11, lapse rates around 7.0 C and helicity values
between 180 and 300 m2/s2. Jet structure shows a nice split in the
winds at 300 mb so it appears all the parameters are in place for
a severe weather event Saturday night. So what could go wrong?
Fcst soundings show a very strong capping inversion that just
vanishes as a cold front and upper level dynamics approach. Not
sure the cap will erode as the models suggest, especially over the
southern half of the region. Took a look back at the CIPS analog
page and previous events with this type of weather pattern only
showed a few severe weather reports over the extreme northern
parts of SE TX. There is still a great bit of uncertainty how this
weather event will unfold so keep up with the forecasts. The cold
front will still trigger a line of shra/tsra Saturday night and
the CIPS page showed about 0.50 to 1.00 inch of rain with past
events. Most of the area should receive some rain with the
heavier totals to the north.

Rain should end around sunrise Sunday morning with skies clearing
by afternoon. High temps will trend cooler with max values in the
mid/upper 70s. Dry conditions will prevail Monday but moisture
levels begin to increase on Tuesday and a few showers will be
possible by Tuesday night as an upper level trough approaches
from the west. The trough coupled with a sfc cold front will bring
the area a good chance of showers and thunderstorms on Wednesday.
Fcst soundings again show some potential for strong storms with
CAPE values above 3500, steep lapse rates and LI values around
-10. Clearing conditions and cooler temperatures are expected in
the wake of the front for Thursday and Friday.

MARINE...
Winds over the bays and Gulf waters are expected to pick up and will
probably reach caution criteria toward sunrise. The big event will
then set up later with advisory conditions expected by sunset. Gusts
to gale force are likely over the Gulf waters later tonight through
at least early Sunday. Winds should diminish as a cold front
approaches the coastline. The result of the strong winds will be
long-period swells and high surf. Forecast models indicate the
possibility of water levels reach over 3.8 feet at Pleasure Pier on
Galveston Island and over 3.5 feet at Freeport. Because of the
potential, have issued a coastal flood watch for overnight tonight
through mid afternoon Saturday.

40

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 90 77 87 57 74 / 10 20 40 80 10
Houston (IAH) 90 78 87 64 76 / 10 20 30 80 30
Galveston (GLS) 84 79 83 68 77 / 10 20 20 80 60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Coastal Flood Watch from late tonight through Saturday afternoon
for the following zones: Brazoria...Chambers...Galveston...
Matagorda.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through this evening for the
following zones: Coastal waters from Freeport to the
Matagorda Ship Channel out 20 NM...Coastal waters from High
Island to Freeport out 20 NM...Galveston Bay...Matagorda
Bay...Waters from Freeport to the Matagorda Ship Channel
from 20 to 60 NM...Waters from High Island to Freeport from
20 to 60 NM.

Small Craft Advisory from 7 PM this evening to 2 PM CDT Sunday
for the following zones: Coastal waters from Freeport to
the Matagorda Ship Channel out 20 NM...Coastal waters from
High Island to Freeport out 20 NM...Waters from Freeport to
the Matagorda Ship Channel from 20 to 60 NM...Waters from
High Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...43
Aviation/Marine...40
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srainhoutx
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Friday morning briefing from Jeff:

Large scale storm system currently over the SW US will arrive into TX this weekend.

Strong low level southerly flow overnight has returned a tropical air mass to the region with origins of this air mass from the smoke and haze filled Bay of Campeche from agricultural fires in Mexico. Low level cloud deck is already starting to break and scatter this morning and when combined with mid level temperatures well into the mid 20C range expect a very warm afternoon with surface temperatures possibly reaching the lower 90’s. This combined with dewpoints in the lower 70’s will support heat index values of 97-102 this afternoon.

Air mass will be strongly capped today into much of Saturday as the storm system approaches from the west. While SPC has outlooked nearly the entire area for severe weather on Saturday night the big question is can the capping inversion be overcome. Forecast soundings show a cap still in place Saturday afternoon although eroding due to surface heating and possibly breakable with surface temperatures in the mid 80’s which appears possible. Models then vanish the capping inversion Saturday night which seems a bit suspect given that capping usually increases after dark and while large scale lift will be increasing the lift looks slightly out of phase with the surface cold front. All of this raises questions as to the potential for severe weather, but the greatest risk areas and forecast confidence.

We have certainly seen this many times before where the cap does not erode especially south of I-10 and those area end up generally with less activity. Global forecast model QPF output is showing that signal with the main convective line passing across the northern portions of the area. While instability and shear will be more than favorable for severe weather it is questionable especially south of I-10 is storms will be able to form. Best chances for strong to severe thunderstorms will be found along and N of I-10 overnight Saturday into Sunday morning.

Moisture values really increase on Saturday with PWS surging to near 2.0 inches which is fairly high for late April. Overall progressive speed of the system and potential for capping issues precludes a significant heavy rainfall and flash flood threat. Think this threat…and a fairly significant one…will be focused from NE TX into AR. Rainfall amounts will likely average 1-2 inches north of I-10 and less than an inch south of I-10.

Marine/Coastal:
Very strong southerly inflow of 25-30kts over the next 24-36 hours will result in NW Gulf of Mexico seas building into the 9-12 foot range. These large swells will result in wave run-up along the Gulf facing beaches and elevated tides. Current tide forecast bring total water levels to near 3.5-4.0 ft on Saturday which is near warning thresholds on Bolivar and portions of the west end of Galveston. Could see some overwash and will likely have water up to the base of the dunes at most locations.

Next Storm System:
Another storm system will approach the area by the middle of next week with additional chances for showers and thunderstorms.
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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Temperatures are rather toasty across SE Texas at this hour. I currently have a 94F reading on my weather station. The GFS continues to indicate a strong cap tomorrow into the overnight hours prior to the front arriving early Sunday morning. Perhaps we can squeeze out about a quarter to a half inch of rainfall tomorrow into tomorrow night, but I suspect the strongest storms will remain well NE of Metro Houston.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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javakah
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Ooph. Hope nobody's planning a camping trip in the Ozarks this weekend. The map looks rather ugly, and that's a pretty good sized area that's going to get slammed.

Although I hate to have to admit it, at the same time it's kind of nice (seemingly for once) to see an ugly QPF map and not be worrying about the proximity of the bullseye to us.
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Continued questions about the cap, expectations of more of a linear storm mode, and expecting the storms around 4 a.m. (Sunday) in Houston itself, gone by probably 7-10 am.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
318 PM CDT Fri Apr 28 2017

.SHORT TERM...
Today resembles more mid/late June than late April with
temperatures in the upper 80s to low 90s. Surface dewpoints are in
the low 70s so combined with the temperatures, heat index values
have reached the upper 90s this afternoon. The only thing that is
making it feel "cooler" are the winds which have been gusting to
30 mph at times. Gusty southerly winds will continue tonight which
means temperatures will not drop too much. Low temperatures in the
upper 70s look on track. This may break a few record high minimum
temperatures for Saturday but that may depend upon cooling
Saturday night as a cold front approaches. The strong winds will
certainly drive up tide levels and increase the threat for rip
currents through tomorrow.

Severe weather threat Saturday night...
Water vapor imagery and upper level analysis show a pretty strong
upper level low over the Great Basin which should drop south
towards the Southern Rockies by 12Z Saturday. A warm front should
extend from the Ozarks SW through Oklahoma to the Trans Pecos of
Texas with perhaps a couple small centers of low pressure along it
depending upon the evolution of convection tonight.

Upper level low should then move towards Tx/Ok Panhandles by 12Z
Sunday allowing for a broad area of large scale lift and height
falls to spread over the region. With this there will also be an
elevated mixed layer support capping over much of SE Texas
Saturday going into Saturday night. Upper level forcing may be
slow to spread over the area depending upon the track of the upper
low. Yesterday this lift looked out of phase with surface forcing
and suggest capping may hinder thunderstorm development. Cold
frontal forcing should be strong enough to at least initiate
linear convection with a squall line moving through the area.
Models differ in instability but overall looks like CAPE over 2000
J/Kg will be possible Saturday night over SE Texas. Deep layer
shear near 40-50 knots may be increasing with strong low level
shear around 20-30 knots during the overnight time frame. This
suggests at least a small tornado threat if a discrete cell can
develop which with the frontal forcing look unlikely since the
cap will be eroding all along the front. Storm model looks linear
as suggested by several of the WRF models so feel confident with a
squall line support hail/damaging wind threats. Any tornado may
be brief and along the squall line. Once again this all depends
upon there being enough instability and that capping weakens.

Basic timing of the line of storms looks to be near midnight
Sunday for the College Station area, 4AM Sunday for Houston area
and off the coast 7-10AM Sunday. Temperatures will be dropping
behind the front into the 60s/50s for Sunday.

Last but not least, the flood threat does not look at great for SE
Texas. While there will be high precipitable water values near 2
inches, the axis of moisture looks to move east Saturday afternoon
and night which would support heavy rainfall more over NE Texas
into Arkansas. The line of storms may produce brief heavy rainfall
but the storms will be moving quickly through the area which will
limit the flood threat.
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jasons2k
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Had a hight today of 94 - that's hot. I was out of town, but I hit 94 a couple of days ago too.
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DoctorMu
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Some instability Saturday, but eroding the cap and timing are still tricky. Highest shear east of College Station. Enhanced Severe threat north of NW Harris Co/Hempstead. Late Night passage should dampen severe threat a little, which will be mostly north and east of HOU.

Probably half an inch of rain - would take an inch! Things are a little dry up in CLL


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unome
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I love a good storm
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Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
427 AM CDT Sat Apr 29 2017

TXZ163-164-176>179-195>200-210>213-226-227-300930-
Austin-Brazos-Burleson-Colorado-Fort Bend-Grimes-Harris-Houston-
Liberty-Madison-Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-
Washington-Wharton-
427 AM CDT Sat Apr 29 2017

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

A strong upper level storm system coupled with a surface cold
front will produce showers and thunderstorms tonight. The best
chance for storms to move across Southeast Texas is between 9 PM
and 5 AM. Some of the storms could become strong to severe with
damaging winds and large hail. The storms will end very early
Sunday morning.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Another storm system will approach the region on Wednesday. Some
of the storms could again be strong to severe with damaging winds
and large hail.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Emergency managers and storm spotters should prepare for possible
activation Saturday night.

$$

TXZ214-235>238-300930-
Brazoria-Chambers-Galveston-Jackson-Matagorda-
427 AM CDT Sat Apr 29 2017

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

A long southerly fetch will produce elevated tide levels along the
coast this morning. Tide levels could rise to between 3.4 and 3.8
feet by Saturday morning and coastal flooding will be possible. A
Coastal Flood Advisory is in effect through mid afternoon.
Beachgoers should be prepared for rough seas and strong rip
currents through the weekend. Strong south winds will persist
today and sustained winds of 25 mph are expected. A Wind Advisory
is in effect through the afternoon.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Another storm system will approach the region on Wednesday. Some
of the storms could again be strong to severe with damaging winds
and large hail.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

$$

GMZ330-335-350-355-370-375-300930-
Coastal waters from Freeport to the Matagorda Ship Channel out
20 NM-Coastal waters from High Island to Freeport out 20 NM-
Galveston Bay-Matagorda Bay-
Waters from Freeport to the Matagorda Ship Channel from 20 to
60 NM-Waters from High Island to Freeport from 20 to 60 NM-
427 AM CDT Sat Apr 29 2017

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

Strong southerly winds will persist today decreasing tonight as a
cold front nears the coast. Winds may gust to gale force at times.
An abrupt wind shift to the north is expected in the wake of the
front on Sunday. A line of strong storms will accompany the cold
front very early Sunday morning. A Small Craft Advisory is in
effect for the coastal waters through Sunday afternoon.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

$$
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Katdaddy
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Severe Thunderstorm Warning
TXC071-201-291-291230-
/O.NEW.KHGX.SV.W.0080.170429T1156Z-170429T1230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Houston/Galveston TX
656 AM CDT SAT APR 29 2017

The National Weather Service in League City has issued a

* Severe Thunderstorm Warning for...
Northwestern Chambers County in southeastern Texas...
South central Liberty County in southeastern Texas...
Southeastern Harris County in southeastern Texas...

* Until 730 AM CDT.

* At 656 AM CDT, a severe thunderstorm was located over La Porte,
moving north at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.

* Locations impacted include...
Eastern Pasadena, Baytown, La Porte, Deer Park, Seabrook, Beach
City, Channelview, Highlands, Barrett, Cloverleaf, northern Clear
Lake, Crosby, Mont Belvieu, Taylor Lake Village, El Lago,
Shoreacres, Old River-Winfree, Cove, Morgan`s Point and eastern
Houston Ship Channel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 2954 9497 2961 9514 2999 9519 2997 9470
TIME...MOT...LOC 1156Z 200DEG 37KT 2968 9505

HAIL...1.00IN
WIND...60MPH
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Katdaddy
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That cell exploded over SE Harris County.
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Katdaddy
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BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Houston/Galveston TX
727 AM CDT SAT APR 29 2017

The National Weather Service in League City has issued a

* Severe Thunderstorm Warning for...
Northwestern Chambers County in southeastern Texas...
Southeastern Liberty County in southeastern Texas...
East central Harris County in southeastern Texas...

* Until 815 AM CDT.

* At 726 AM CDT, a severe thunderstorm was located over Mont Belvieu,
or 10 miles east of Barrett, moving northeast at 35 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.

* Locations impacted include...
Northeastern Baytown, Liberty, Dayton, Beach City, Highlands,
Barrett, Mont Belvieu, Old River-Winfree, Ames, Daisetta, Hardin,
Kenefick, Cove, Devers, Dayton Lakes and Moss Hill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.
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https://twitter.com/iembot_hgx

https://mesonet.agron.iastate.edu/lsr/# ... 00459/0100

http://www.spc.noaa.gov/products/md/2017/md0591.html

http://weather.cod.edu/satrad/exper/?pa ... tx-02-24-1

http://weather.cod.edu/satrad/exper/?pa ... tx-13-24-1

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Mesoscale Discussion 0591
NWS Storm Prediction Center Norman OK
0919 AM CDT Sat Apr 29 2017

Areas affected...southeast Texas through western Louisiana

Concerning...Severe potential...Watch possible

Valid 291419Z - 291615Z

Probability of Watch Issuance...40 percent

SUMMARY...Cluster of storms over southeast TX will pose some risk
for isolated strong to damaging wind gusts, large hail and possibly
a brief tornado as it continues northeast this morning. Need for a
WW remains uncertain at this time due to potential limiting factors
for a more sustained severe threat, but trends will continue to be
monitored.

DISCUSSION...Small cluster of storms over southeast TX appears to
have initiated in association with an upper vorticity maximum
depicted on the RAP near the TX coast and is also evident on WV
imagery. The atmosphere is strongly unstable based on the 12Z RAOB
and latest RAP analysis, but a capping inversion near 700 mb at base
of the elevated-mixed layer, along with widespread low clouds will
continue to limit low-level lapse rates and provide a somewhat
hostile environment for robust low-level updraft accelerations.
Despite these limiting factors, moist and unstable inflow from a 50+
kt sly low-level jet may be sufficient to help sustain activity
another few hours through southeast TX into western LA. While 0-1 km
hodographs are large and would support a conditional risk for at
least transient low-level mesocyclones, winds at or above 500 mb and
vertical shear through a deeper layer are relatively weak which
should provide a limiting factor for sustained updraft rotation.
However, activity will pose a near-term threat for mainly isolated
large hail and damaging wind and will continue to be monitored for
possible organization.

..Dial/Weiss.. 04/29/2017

...Please see http://www.spc.noaa.gov for graphic product...

ATTN...WFO...LCH...SHV...HGX...
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jasons2k
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The way those storms just exploded - I wonder if that's an indication that the cap is not as strong as they are saying?
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srainhoutx
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For what it's worth, the 13Z HRRR initiated the storms that blew up over SE Harris County and moved them NE with not much else expected until overnight when a skinny line of showers passes.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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