Wednesday, December12, 2018

Marine Weather and Tides
Kerrville, TX

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:22AMSunset 5:39PM Wednesday December 12, 2018 5:31 AM CST (11:31 UTC) Moonrise 11:26AMMoonset 10:29PM Illumination 24% Phase: Waxing Crescent; Moon at 5 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 Kerrville city, TX
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location: 30.01, -99.21     debug

Area Discussion for - Austin/San Antonio, TX
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Fxus64 kewx 120902
area forecast discussion
national weather service austin san antonio tx
302 am cst Wed dec 12 2018

Short term (today through Thursday night)
Low and high level clouds are in place across much of south central
texas at the present time. Southerly flow has also returned and with
that an increase in surface dewpoints. With the increase in surface
moisture, some members of guidance continues to show the possibility
of some fog around or after daybreak for portions of the western cwa.

Have not seen any fog reported yet, but will continue to monitor for
any needed updates to the current area of fog we have in the

Latest water vapor imagery shows a strong shortwave trough axis south
of california moving to the east. Ahead of it, clouds moisture should
continue to stream east over texas. The influences of this system
will begin to be felt later today with some weak light showers
possible in the eastern counties. Highs today will top out in the
lower 60s to near 70 degrees.

More significant upper forcing arrives this evening as the shortwave
reaches the region. Latest runs of both the synoptic and high-res
models show a decent coverage of shower activity this evening and
overnight. Will show 20 pops in the edwards plateau, 30-40 pops for
the hill country and i-35 37 corridors and 50-60 pops for the eastern
cwa in the tonight period. There should be enough instability to
support some isolated thunderstorms as well and will mention iso-t
with the chance of showers. Lows tonight will bottom out in the
middle 40s to near 60 with the cooler temperatures west of highway

A secondary, but stronger upper low will drop in from the northwest
on Thursday into the region. This system is now beginning to enter
the pacific northwest and can also be seen on water vapor. This low
will be compact but dynamic with tight pressure gradients and a
strong wind field associated with it. The cold front or leading edge
to the higher winds will arrive to the western CWA in the mid-morning
hours before quickly overtaking the rest of the cwa. The main story
on Thursday will be the high winds associated with this system behind
the front. By the mid-late afternoon hours expect sustained speeds
around 25-35 mph with gusts up to 50 mph possible over a large part
of the CWA with the higher winds mainly west of the i35 corridor.

Wind speeds should be highest for the rio grande counties. Will
likely need a wind advisory for tomorrow and this may need to be
issued on the day shift, or definitely by the midnight shift tonight.

With the expected high winds and dry air there will definitely be a
fire weather threat and for more information on that see the fire
weather section at the end of the afd.

The talk over the past several days has been over the eventual track
of the upper low and the influence that would have for the weather in
our northern counties Thursday afternoon through Thursday night. A
more northerly track would mean we'd get the mid-level dry slot and
not much in the way of precip chances, but a track more to the south
would equate to wrap around moisture and precipitation. As previously
mentioned, the trough axis has now moved over the NW CONUS and was
sampled by 00z upper air soundings. As a result, models have honed in
on a track that favors the southerly track the ECMWF has been showing
over the past several days. By late Thursday afternoon, clouds will
once again be on the increase as the low begins to move east of the
area and wrap around moisture moves into the area.

The focus then shifts on precip type for our northern counties. We
favor a top-down approach of the atmosphere to determine precip type.

By the evening hours, moisture quickly increases with near saturation
from the tropopause down to about 850 mb. Moisture in the dendritic
ice growth zone means snow will be produced by the lift on the
backside of the low. Then looking at the temperature profile, models
show a freezing level across the CWA in the evening hours ranging
from 3250 feet across llano county with higher values elsewhere. This
would support all precip melting in this surface to freezing level
layer with a rain forecast. However, forecast soundings show a decent
dry layer below 850 mb. If precipitation were heavy enough, some
evaporative cooling would be expected which would cool this small
portion of the column and thus lowering the freezing level. Models
don't really do a good job simulating this so we will have to infer
that it is possible. With these deep core systems, there can easily
be a burst in precipitation on the backsides that would support this
outcome. Therefore, some snow mixing in with the rain is possible
for portions of our CWA Thursday night as the upper low exits to the
east. For now will include a mention of rain or snow for areas north
of a line from kerr county to northern kendall county to burnet
county. This area is where the GFS forecast surface wet bulb
temperatures of 34 degrees. The wet bulb temperature is the
temperature of the air if full evaporative cooling could take place.

Since we are not expecting temperatures to reach freezing Thursday
night, any impacts from possible snowfall would be minimal with brief
accumulations only possible on grassy or elevated surfaces. Rain
will be in the forecast for other areas north of a bandera to comal
to fayette county line. The chances of accumulating snow will be best
well to our north, in the san angelo and fort worth cwas.

Long term (Friday through Tuesday)
The upper low is expected to push east by Friday morning and will
show a dry forecast Friday and through the early part of next week.

Shortwave ridging is expected to briefly return which should help
keep the forecast dry. Highs will then begin to moderate with highs
back into the middle to upper 60s by Monday. Models have backed up
the timing of the next system into Wednesday instead of Tuesday and
took out the low rain chances for Tuesday.

Fire weather
Very strong northwest flow will develop Thursday afternoon across
south-central texas. The strongest winds will be along the rio
grande and over the hill country, where gusts between 40-50 mph are
likely. Breezy conditions will also occur eastward into portions of
the i-35 corridor, where wind gusts of 30-40 mph are likely.

Afternoon humidity values will be near 30 percent for the rio grande
counties and the southwest cwa. A fire weather watch for critical
fire weather conditions remains in effect for this region given the
forecast wind speeds and rh values combined with cured winter fuels.

Elevated to near-critical fire weather conditions will exist
elsewhere across south central texas Thursday and again across much
of the area on Friday when humidity values drop even lower.

Preliminary point temps pops
Austin camp mabry 66 55 59 39 53 - 50 10 20 -
austin bergstrom intl airport 67 55 60 40 54 10 50 10 20 -
new braunfels muni airport 68 54 61 39 56 10 40 10 10 0
burnet muni airport 65 50 54 35 51 - 30 30 40 10
del rio intl airport 62 47 57 37 62 0 10 0 0 0
georgetown muni airport 65 54 57 38 51 - 40 10 40 10
hondo muni airport 67 49 58 36 61 - 20 - 10 0
san marcos muni airport 67 54 61 39 56 10 50 10 20 0
la grange - fayette regional 68 59 64 41 53 20 50 10 10 10
san antonio intl airport 67 54 60 39 58 10 40 10 10 0
stinson muni airport 68 53 63 40 60 10 40 10 10 0

Ewx watches warnings advisories
Fire weather watch from Thursday morning through Thursday evening
for dimmit-frio-kinney-maverick-uvalde-val verde-zavala.

Aviation... 17
short-term long-term... Hampshire

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Kerrville, Kerrville Municipal Airport/Louis Schreiner Field, TX7 mi36 minS 410.00 miPartly Cloudy51°F48°F89%1018.3 hPa
Fredericksburg, Gillespie County Airport, TX23 mi56 minSSW 710.00 miMostly Cloudy52°F48°F88%1017.6 hPa

Wind History from ERV (wind in knots)
Last 24hrCalmCalmCalmCalmS11
1 day agoCalmN4NW4NW3W3CalmNW5CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm
2 days agoNW4NW4NW6N11NW14N13

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of SouthCentralPlains    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Austin/San Antonio, TX (6,6,7,8)
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Ground Weather Radar Station Austin/San Antonio, TX
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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.