Thursday, April27, 2017

Marine Weather and Tides
Galveston, TX

Version 3.4
What's New / NOTES
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:38AMSunset 7:54PM Thursday April 27, 2017 9:29 PM CDT (02:29 UTC) Moonrise 6:48AMMoonset 8:24PM Illumination 4% Phase: Waxing Crescent; Moon at 2 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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GMZ375 Waters From Freeport To The Matagorda Ship Channel From 20 To 60 Nm-waters From High Island To Freeport From 20 To 60 Nm- 401 Pm Cdt Thu Apr 27 2017
.small craft should exercise caution after midnight...
Tonight..Southeast winds 10 to 15 knots becoming south 15 to 20 knots after midnight. Seas 3 to 4 feet increasing to 4 to 6 feet after midnight.
Friday..South winds 15 to 20 knots. Seas 4 to 5 feet with occasional seas up to 6 feet building to 5 to 7 feet with occasional seas up to 8 feet in the afternoon.
Friday night..Southeast winds 20 to 25 knots. Seas 6 to 8 feet with occasional seas up to 10 feet building to 8 to 10 feet with occasional seas up to 13 feet after midnight.
Saturday..Southeast winds 20 to 25 knots. Seas 9 to 11 feet with occasional seas up to 14 feet. A slight chance of showers and Thunderstorms in the afternoon.
Saturday night..South winds 20 to 25 knots becoming southwest 20 to 30 knots after midnight. Seas 10 to 12 feet with occasional seas up to 15 feet subsiding to 8 to 11 feet with occasional seas up to 14 feet after midnight. A slight chance of showers and Thunderstorms in the evening, then showers and Thunderstorms likely after midnight.
Sunday..Northwest winds 15 to 25 knots becoming 15 to 20 knots in the afternoon. Seas 8 to 10 feet with occasional seas up to 13 feet subsiding to 6 to 8 feet with occasional seas up to 10 feet in the afternoon. A chance of showers and Thunderstorms in the morning.
Sunday night..North winds 15 to 20 knots becoming northeast 10 to 15 knots after midnight. Seas 5 to 7 feet with occasional seas up to 8 feet.
Monday..Southeast winds 5 to 10 knots. Seas 3 to 5 feet.
Monday night..Southeast winds 10 to 15 knots. Seas 2 to 3 feet.
Tuesday..Southeast winds around 15 knots. Seas 2 to 4 feet building to 4 to 6 feet with occasional seas up to 7 feet in the afternoon.
Tuesday night..Southeast winds around 15 knots. Seas 5 to 6 feet with occasional seas up to 7 feet. A chance of showers and Thunderstorms.
GMZ300 Synopsis For High Island To The Matagorda Ship Channel Out 60 Nautical Miles Including Galveston And Matagorda Bays 401 Pm Cdt Thu Apr 27 2017
Synopsis for high island to matagorda ship channel out 60 nm.. Onshore winds will continue to develop over the region as high pressure drifts further east. This southeasterly flow will be strengthening through Saturday.

7 Day Forecast for Marine Location Near Galveston, TX
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location: 28.84, -94.35     debug

Area Discussion for - Houston/Galveston, TX
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Fxus64 khgx 280126
area forecast discussion
national weather service houston/galveston tx
826 pm cdt Thu apr 27 2017

Increasing clouds and strengthening southeast winds can be expected
overnight as high pressure continues moving off to the east and low
pressure deepens across northwest texas. Some patchy fog might develop,
but think a majority of the area will just see the clouds. Not much
to change in the grids on the evening update as everything looks to
be on track. 42

Prev discussion /issued 645 pm cdt Thu apr 27 2017/

deeper lower level moisture currently residing over the coastal
bend will advect up within a regional southwesterly flow pattern
this evening. The lower 2k ft level will saturate up later this
evening... Anticipating areawide MVFR ceilings by 10 or 11 pm lt.

Deepening moisture will likely have decks lowering to near... Or
falling just below... Ifr categories during the pre-dawn hours.

Lowering pressures over west texas will maintain a tight enough
onshore gradient to maintain near 10 knot southerlies... Strengthening
to between (sustained) 15-20 knots by tomorrow afternoon. These
winds should inhibit any significant early day fog formation.

Little change to low level moisture and a strong lower level
inversion will allow for very slow improvement toVFR tomorrow...

interior sites begin to lift and scatter out during the afternoon
hours. 31
prev discussion... /issued 355 pm cdt Thu apr 27 2017/
short term...

today's nice weather with low humidity and mostly clear skies will
come to an end tonight and tomorrow. Southerly winds are already
developing across SE texas based on latest surface analysis. Deep
gulf moisture is not far away and should return tonight. Short
term guidance shows temperatures falling after sunset but may
actually warm overnight as moisture return increases. Low
temperatures in the 60s will be common but even low 70s will be
possible along the coast. Patchy fog may also develop tonight with
the increase in moisture.

Long term...

main focus of the forecast update was on Saturday and Sunday with
a deep trough developing over the southern portions of the 4
corners region. Models show this upper low moving towards texas
panhandle and southern plains by 12z Sunday. Gfs/nam seem 3-6 hrs
faster with the trough than the ecmwf/cmc. A cold front associated
with the system should push into SE texas 00-03z Sunday, about 12
hours in advance of any strong PVA or large scale ascent. Frontal
forcing may be enough to get a strong or severe storm to develop
late evening through the overnight. Models all maintain weak
capping if any which experience says the elevated mixed layer will
be stronger than forecast. Also very few models are actually
producing storms during the day Saturday suggesting the cap
holding. By Saturday night, instability should be decreasing with
loss of heating and without strong cooling aloft since upper
dynamics are out of phase with the surface forcing, the severe
threat may end up being more isolated. SPC has elevated/slight
risks for the area which if a storm forms in the environment, it would
likely become severe with hail/wind threats. Tornado threat will
be hampered by the lack of strong upper level winds which only
increase after 06z Sunday (out of phase upper trough finally
making its presence felt). This means deep layer shear may not be
strong enough to support rotating updrafts. Low level shear may
support some rotation but overall helicity values are only
borderline supportive of rotation. Storm mode will be another
issue and expect linear convection to form along the front. There
might be a strong enough squall line to briefly support wind/hail
threats but the convection will be fighting lack of instability
and capping. There is just enough factors that support severe
weather that it deserves mention and no let our guard down.

Moisture will be increasing so there may be a locally heavy
rainfall threat. This appears to be more north of houston where
there will better forcing. Also models show main moisture axis
shifting east Saturday night with only enough moisture convergence
along the front to increase precipitable water values. Pwat values
of 1.8-2 inches is nothing to sneeze at, but with storms expected
to be moving along a cold front the flood threat looks rather
small at this time for much of SE texas. Where storms can train
along the front as they move NE along it like in NE texas into
louisiana, flooding will be more likely. Overall looking at 1-2
inches of rainfall for the northern third of the forecast area and
less than an inch for much of the area.

The cold front pushes through off the coast Sunday morning which
will provide a good cool down for Sunday through Tuesday. Tuesday
southerly return flow ramps up again ahead of the next upper level
system crashing down through the rockies into the plains. Models
show strong moisture return on Wednesday so increase rain chances
for the area. Cold front should push through Wednesday night into
Thursday. This will likely be the next time frame to monitor for
severe weather and perhaps heavy rainfall. 39

winds over the coastal waters are continuing to shift to the e/se
this afternoon as the surface high moves further east. An onshore
flow is expected to be in place areawide this evening with speeds
picking up overnight. Have issued an scec for the offshore waters
for after midnight and this could be expanded to include the nearshore
waters by tomorrow morning. Small craft advisories might be needed
by tomorrow afternoon as the pressure gradient tightens in response
to deep low pressure over south tx. The low will move NE and drag
another cold front across SE tx by early Sun morning. An abrupt
wind shift to the nnw is expected in the wake of the front and
another SCA will likely be required on sun. A light/moderate
onshore flow will prevail mon/tues.

Will need to keep an eye on elevated water levels and risk of rip
currents going into the weekend. Tide levels could potentially exceed
3.5 feet around high tide early Sat morning. A coastal flood watch
or advisory may be required late Friday night into early Saturday.


Preliminary point temps/pops
College station (cll) 68 91 75 87 57 / 10 10 20 30 80
houston (iah) 70 90 77 85 64 / 10 10 20 30 80
galveston (gls) 72 84 77 83 68 / 10 10 20 30 80

Hgx watches/warnings/advisories
Tx... None.

Gm... Small craft should exercise caution from 1 am cdt Friday through
Friday morning 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.

Discussion... 42
aviation/marine... 31

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
KXIH 25 mi35 min SSE 18 73°F 68°F
42035 - GALVESTON 22NM East of Galveston, TX 27 mi100 min ESE 16 G 18 73°F 75°F3 ft1005.5 hPa (-0.3)68°F
GTOT2 40 mi42 min 73°F 75°F
GNJT2 - 8771341 - Galveston Bay (North Jetty), TX 41 mi42 min ESE 15 G 19 1005.6 hPa
GRRT2 43 mi42 min SE 8.9 G 13 73°F 75°F1005.7 hPa
LUIT2 44 mi42 min E 12 G 15 74°F
RLOT2 - 8770971 - Rollover Pass, TX 47 mi42 min SE 14 G 16 73°F 75°F1006 hPa

Wind History for Galveston Pleasure Pier, TX
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1 day
2 days

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
High Island 179A (Apache Corp), LA25 mi55 minSSE 169.00 miOvercast73°F66°F78%1005.8 hPa

Wind History from XIH (wind in knots)
Last 24hrNE26
1 day agoS16
2 days agoSW11SW13

Tide / Current Tables for Galveston Pleasure Pier, Gulf Of Mexico, Texas (sub)
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Galveston Pleasure Pier
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Thu -- 05:01 AM CDT     2.49 feet High Tide
Thu -- 06:40 AM CDT     Sunrise
Thu -- 07:49 AM CDT     Moonrise
Thu -- 11:07 AM CDT     1.48 feet Low Tide
Thu -- 02:51 PM CDT     1.91 feet High Tide
Thu -- 07:53 PM CDT     Sunset
Thu -- 09:26 PM CDT     Moonset
Thu -- 10:37 PM CDT     -0.24 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Galveston (Pleasure Pier), Texas
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Galveston (Pleasure Pier)
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Thu -- 05:30 AM CDT     2.58 feet High Tide
Thu -- 06:40 AM CDT     Sunrise
Thu -- 07:49 AM CDT     Moonrise
Thu -- 11:34 AM CDT     1.33 feet Low Tide
Thu -- 03:53 PM CDT     1.81 feet High Tide
Thu -- 07:53 PM CDT     Sunset
Thu -- 09:26 PM CDT     Moonset
Thu -- 10:53 PM CDT     -0.17 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Weather Map and Satellite Images
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Weather Map
IR Satellite Image from GEOS

GOES Local Image of SouthCentralPlains    EDIT

Wind Forecast for Houston/Galveston, TX (22,6,7,8)
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Ground Weather Radar Station Houston/Galveston, TX
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Gulf Stream Current

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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.