Friday, July20, 2018 L-36.com


Marine Weather and Tides
Pell City, AL

Version 3.4
What's New / NOTES
5/20/2018 -- NOAA is having problems with the data feed that I use to draw the graphs. They are aware of the issue and working to resolve it. Sometimes changing the location by about a mile will give a correct graph. 3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.

Sunrise 5:48AMSunset 7:53PM Friday July 20, 2018 11:45 AM CDT (16:45 UTC) Moonrise 1:53PMMoonset 12:41AM Illumination 53% Phase: First Quarter Moon; Moon at 8 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 Pell City, AL
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location: 33.61, -86.29     debug


Area Discussion for - Birmingham, AL
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Fxus64 kbmx 201126
afdbmx
area forecast discussion
national weather service birmingham al
626 am cdt Fri jul 20 2018

Update
For 12z aviation.

Short term
Today through tomorrow.

There are two main stories for today, the dangerous heat during the
day followed by the potential for severe weather in the evening and
overnight hours.

Synoptically, a couple of things are taking place. First, we've got
upper level ridging over the 4-corners region that has persisted for
several days already, leading to hot conditions across the south
central and southwestern us. Naefs highlights the geopotential
heights in this ridge as being in the 99th percentile for this time
of year. Second, a very strong low pressure system slides
southeastward through the northern plains and into the midwestern
states. Naefs picks this up as having minimum all time heights at
850mb and a minimum mslp. In other words, an unusually strong ridge
is place across the southwest as a highly anomalous low dips into
the midwest. This contrast between these two systems unsurprisingly
generates an anomalously strong jet, which at 500mb, is being shown
near the MAX climatologically. Basically, this is an unusual pattern
for july.

Let's begin with the heat:
low level ridging at 850mb is centered over louisiana early
Friday. This will lead to subsidence and an overall suppression of
cloud cover and convection during the day, allowing central al to
heat up into the low to mid 90s, with the warmest temps in the
western and southwestern counties. Surface winds are forecast to
be nearly due south, which will bring in quite a bit of moisture,
helping dewpoints increase to the mid 70s. The NAM even brings in
a narrow corridor of upper 70s dewpoints right along the al ms
state line, further increasing the heat indices in that area. A
heat advisory will be in place for the western and southern
counties of central al from noon to 7pm when heat indices will
likely exceed 105 degrees.

The severe threat will primarily be in the evening and into the
overnight hours Saturday morning. A shortwave slides through the
strong upper level trough and pushes southward through the mid ms
valley and into western tn. Initially, models are having a hard time
resolving whether this will generate discreet supercells or a squall
line MCS feature in western kentucky and into tn. Depending on which
convective-allowing model you look at and what run of that model,
you might get one solution or the other. Regardless, of the initial
mode, cams generally agree that as the event begins to our north.

The system then becomes more of an MCS that dives southward into
north al and continues into central al. The GFS and nmm have this
mcs focused along the al ms state line along the axis of higher
instability (4000-5000 j kg cape), which would make sense based on
how MCS propagation should take place. The NAM and ECMWF generally
have a more eastward focus that pushes through eastern portions of
central al, but this solution seems less likely as it doesn't follow
the better instability. Finally, the arw pushes the stronger mcs
feature more through mississippi. I say all of that to essentially
lay out the uncertainty of the forecast and where the the potential
mcs will move because it will highly depend on where storms initiate
upstream. The current forecast has the best chance for impacts in
the northwestern counties, highlighted in an enhanced risk. This is
based on where the environment is most conducive to support strong
to severe storms as the shortwave forcing moves through. Threat
wise, the biggest concern will damaging winds. Models generally
agree that as storms reach central al, the mode should be more of an
mcs-type event rather than discreet cells. Abundant shear is in
place to support rotating updrafts, but i'm not sure we'll see
storms develop out ahead of the MCS cluster, which would usually
lead to tornado concerns. I won't rule out the possibility of an
isolated tornado or two if a discreet storm can get going, but
confidence is very low, so will continue mention of damaging winds
as the main threat for this event.

By Saturday morning, the initial shortwave has pushed south of our
area and the upper level jet begins to nose into central al. Models
pick up on another shortwave developing Saturday afternoon in
northeastern al northern ga and pushing southward, which could set
off another MCS that pushes through our northeastern and eastern
counties. The placement of that shortwave will determine if any of
our area sees the chance for severe storms Saturday. Right now, i
can't rule out a damaging wind threat for our far eastern portions,
but I believe the best chances will be further east into georgia.

Therefore, I will continue mention of severe weather Saturday
afternoon evening, but keep it generally east of the i-65 corridor.

After this second shortwave pushes through late Saturday evening
into the overnight hours, we should see improving conditions across
central al with the best rain storm chances ending before midnight
Saturday night.

25 owen

Long term
Sunday through Thursday.

The main upper low, currently associated with the weather in the
short term, will slowly slide southward on Sunday and Monday. As it
slides south, it will weaken as well. This low will then park over
the southeast for the rest of the week. There are some model
disagreement with the exact track and overall timing, but the
pattern remains similar, so confidence is high that we will see
above normal rain chances for much of the next work week. The euro
places the center of the low over northern ga al Monday afternoon
and keeps it generally in the same location through Wednesday. After
that the energy gets shifted to the south along the coast through
the end of the week. Meanwhile the GFS bring the center of the low
more into northern al ms by Tuesday morning. The low spins across
central al before it weakens into more of an upper trough. Either
scenario would keep higher than normal precipitation chances for the
area, with the only uncertainty being where to put the highest
chances. As for temperatures, will trend temperatures in the upper
80s to near 90 for now and adjust downward if needed as we get
closer and confidence of the path is higher. The good news is that
the lows should be cooler, with the lower dewpoints, so the
oppressive heat will not be as much of an issue.

16

Aviation
12z TAF discussion.

Looking at only a few hours of ifr MVFR ceilings in the east.

Otherwise improving skies through the day, with generally
scattered decks and very little chance of rain through 00z. Then
we will watch a MCS develop and slide south through a good portion
of the area. Went with predominant vcts at all sites after 00 to
03z with a prob30 after that for 6 hours. The question isn't
really will it rain but exact timing of the rain and stronger
winds. Updates to the exact timing will be made with the 18z and
00z sets.

16

Fire weather
Only isolated showers storms this afternoon, with an increase in
coverage this evening as a strong system slides through. Strong
winds will be associated this system this evening as well as heavy
rainfall. Additional scattered showers storms Saturday and Sunday
afternoon. Higher rain chances continue into the work week as well,
with slightly cooler temperatures. Localized fog will be possible
each morning over the next couple of days where rainfall occurs
during the previous afternoon and evening. There are no fire weather
concerns.

Preliminary point temps pops
Gadsden 92 71 91 70 88 20 60 50 50 30
anniston 92 71 91 71 89 20 50 50 50 30
birmingham 93 73 92 73 91 20 60 40 30 20
tuscaloosa 95 73 94 75 93 20 70 30 20 10
calera 92 71 91 73 91 20 50 40 30 20
auburn 89 74 90 72 90 20 20 50 50 30
montgomery 94 75 94 75 94 20 30 40 40 30
troy 92 75 92 75 93 20 20 40 50 30

Bmx watches warnings advisories
Heat advisory from noon today to 7 pm cdt this evening for the
following counties: autauga... Bibb... Chilton... Dallas... Elmore...

fayette... Greene... Hale... Lamar... Lowndes... Marengo... Marion...

montgomery... Perry... Pickens... Sumter... Tuscaloosa... Walker...

winston.



Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Anniston Metro Airport, AL23 mi53 minESE 510.00 miFair83°F72°F70%1015.6 hPa

Wind History from ANB (wind in knots)
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Last 24hrSE333CalmSE6NE15
G21
E4CalmE3E5NE6NE6NE6E5NE3NE3NE4NE4NE6NE3NE45NE6SE5
1 day ago33CalmN7NE6N7NE8NE6CalmCalmCalmCalmCalmCalmCalmCalmCalmE3E3NE3E4NE45E4
2 days agoSW7SW6SW7W7W9SW7SW7SW6SW3E3N3CalmCalmCalmNE3CalmCalmSW3W4SW3CalmCalmCalmCalm

Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of    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 Birmingham, AL (12,3,4,5)
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Ground Weather Radar Station Birmingham, AL
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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.