Friday, December15, 2017 L-36.com


Marine Weather and Tides
Castle Hills, TX

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
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.

Sunrise 7:20AMSunset 5:39PM Friday December 15, 2017 8:07 AM CST (14:07 UTC) Moonrise 4:56AMMoonset 4:09PM Illumination 8% Phase: Waning Crescent; Moon at 27 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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7 Day Forecast for Marine Location Near Castle Hills, TX
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location: 29.51, -98.53     debug


Area Discussion for - Austin/San Antonio, TX
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Fxus64 kewx 151115
afdewx
area forecast discussion
national weather service austin san antonio tx
515 am cst Fri dec 15 2017

Update
12z aviation update below.

Aviation
Vfr conditions today and tonight. A bkn-ovc 10-12k foot deck will
shift south later this morning leaving behind bkn high cirrus.

Lowering ceilings to around 6k feet will take place late morning on
Saturday as -ra develops SW to ne.

Winds generally NW to NE 6-11 kts through the morning and early
afternoon hours, decreasing to less than 5 kts at Sat aus this
evening and turning S to SE at drt around 5 kts.

Prev discussion issued 414 am cst Fri dec 15 2017
short term (today through Saturday)...

the short term forecast focused heavily on Saturday's rainfall
potential associated with the impressive dynamical system progged to
move through Saturday. While the overall forecast has not changed
significantly with this package compared to the previous forecast,
confidence continues to increase on pop potential and areas of higher
qpf potential.

For today, the colder air is knocking on the door of the northern cwa
border as of 330am. While north winds have been noted across the cwa
already, the colder air is lagging behind significantly, and the temp
gradient is finally beginning to enter the northern tier of the cwa.

This should slowly continue across the southern plateau today and
combined with mostly cloudy skies across much of the area, should
prevent highs from reaching the 60s today. The light but widespread
shower activity seen along i-10 this morning should continue to
slowly push southeast as drier low level air filters into the cwa.

Thus have lowered pops over the course of the day and favoring the
southern third of the cwa.

A brief lull in activity is expected overnight tonight before the
main rain event Saturday. The weak closed low over mexico responsible
for this event will begin to interact with the quickly approaching
shortwave diving south from the pacific northwest. This will force
the mexican low to swing northeast, undergo a shift to a negative
tilt, eject PVA across texas, and put the region in a southwest flow
regime and increasing upper level winds divergence.

While the atmospheric column will begin initially dry below 500 mb
Saturday morning, the column is progged to quickly moisten as low
level flow becomes southerly and surface low pressure develops over
south texas and the southern texas coast. This will likely result in
elevated shower activity in the morning hours approaching from the
south, but increasing in coverage and intensity throughout the course
of the day as lifting becomes more focused due to focused isentropic
lift, pwats increasing to over an inch, moisture flux convergence
and ul divergence all phase, according to the 00z and 06z GFS and 00z
ecmwf, by 18z Saturday afternoon across the i-35 corridor. Around
this time, expectations are for precip intensity to increase to more
moderate, with some locations seeing some periodic, locally heavy
rainfall, especially east of i-35. Forecast soundings continue to
show little to no instability, and while that should serve as the
main reason for limiting this activity from becoming impactful, there
is more than enough isentropic and dynamical lift to produce
widespread rain activity with some embedded isolated thunderstorms.

As far as QPF potential goes, there is a strong favoring in various
ensemble members for the eastern CWA to see around a half inch to an
inch of rain Saturday when all is said and done. The outlier seems to
be the deterministic gfs, which produces closer to 2 inches Saturday
night along the extreme eastern cwa, but ensemble member spread
varies considerably, and the 06z run puts this qpf MAX farther into
east texas than the 00z run. Would not be surprised to see further
acceleration of this system as we approach Saturday as this has been
the trend throughout the last several days. And if so, storm total
qpf would likely decrease due to the faster passage of the upper low.

Long term (Saturday night through Thursday)...

as the aforementioned system continues to accelerate with each
successive run, the cessation of rainfall for the CWA becomes earlier
and earlier, now fully east of the i-35 corridor by 12z Sunday, if
not completely east of the cwa. Thus, pop chances have been removed
after 12z Sunday completely and highs increased into the mid to upper
60s.

After Sunday, the forecast confidence decreases as consistency has
been lacking from run to run and model to model. Models seem to be
having trouble progressing the secondary low center after Sunday.

While there is consensus for this feature to become a closed system
south of the four corners late Sunday, the speed of the eastward
progression of this low is still unclear. The 06z GFS has trended
more in line with the 00z ECMWF but this has not been the case in the
last few runs. What it seems to boil down to is a prolonged
possibility for pops across the eastern zones as continued low level
moisture pumps into the eastern third of texas. The weaker, but still
adequate lift from this next shortwave should maintain rain chances
through the mid week across southeast texas.

Preliminary point temps pops
Austin camp mabry 59 41 56 44 67 10 - 80 70 -
austin bergstrom intl airport 58 41 55 42 67 10 - 80 80 -
new braunfels muni airport 59 43 54 43 67 20 - 90 70 -
burnet muni airport 56 37 54 42 68 10 - 70 60 -
del rio intl airport 59 42 52 41 63 10 20 40 10 0
georgetown muni airport 57 38 56 42 68 10 - 70 70 -
hondo muni airport 60 43 54 40 66 20 10 80 40 -
san marcos muni airport 58 42 55 43 67 20 - 90 70 -
la grange - fayette regional 58 41 57 44 67 10 - 80 90 -
san antonio intl airport 59 44 54 44 67 20 - 90 60 -
stinson muni airport 60 44 54 43 67 20 10 90 60 -

Ewx watches warnings advisories
None.

Mesoscale aviation... Runyen
synoptic grids... Tb3


Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
San Antonio, San Antonio International Airport, TX4 mi77 minN 910.00 miMostly Cloudy48°F30°F50%1024.4 hPa
Kelly Air Force Base, TX9 mi72 minN 810.00 miFair47°F32°F56%1024.7 hPa
San Antonio, Stinson Municipal Airport, TX13 mi75 minN 710.00 miMostly Cloudy50°F32°F50%1024.7 hPa
Randolph Air Force Base, TX13 mi72 minN 510.00 miOvercast46°F32°F58%1025.1 hPa
San Antonio Boerne Stage Field, TX17 mi73 minN 510.00 miFair43°F28°F57%1025.7 hPa
Castroville Municipal Airport, TX21 mi73 minNNW 510.00 miOvercast47°F33°F61%1026.1 hPa

Wind History from SAT (wind in knots)
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Last 24hrW4NW5NW5N6N6N7NE6N7NE5N4N7N8N12
G19
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G18
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G18
N6N3N6N5N4N9NW8
1 day agoNW4SW5SW6SW6SW7S9SW7SW7SW5SW5SW5SW5SW6SW5SW6SW6CalmCalmCalmNW4W3NW3NW3NW3
2 days agoN11
G19
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NE13
G22
N13N8NE10N6
G15
NW6N9N3NW4NW6NW5NW6NW6NW4NW6NW5CalmW4NW6NW5NW5NW5

Tide / Current Tables for
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Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
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GOES Local Image of SouthCentralPlains    EDIT
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Wind Forecast for Austin/San Antonio, TX (9,2,3,4)
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Ground Weather Radar Station Austin/San Antonio, TX
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Disclaimer:
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 L-36.com. 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 L-36.com 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.