Thursday, July18, 2019

Marine Weather and Tides
Marietta, GA

Version 3.4
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at Allen

Sunrise 6:38AMSunset 8:50PM Thursday July 18, 2019 5:17 PM EDT (21:17 UTC) Moonrise 9:17PMMoonset 7:06AM Illumination 97% Phase: Waning Gibbous; Moon at 16 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 Marietta, GA
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location: 34, -84.47     debug

Area Discussion for - Peachtree City, GA
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Fxus62 kffc 181940
area forecast discussion
national weather service peachtree city ga
340 pm edt Thu jul 18 2019

Short term tonight through Friday night
To begin the short term period, a 500 mb longwave trough is
positioned over the atlantic coast, promoting northwesterly flow
aloft on the backside of the trough. At the surface, a weak surface
trough remains in place into central georgia. Showers and
thunderstorms are ongoing across the forecast area, focused along a
southeastward moving shortwave embedded within the upper level
northwesterly flow and the surface trough. The highest convective
coverage is currently located near the atlanta metro area and on an
e-w line across central georgia from near columbus to macon.

Additional diurnally driven convection is furthermore possible
throughout the remainder of the afternoon and into the evening.

In typical july fashion, the atmosphere will remain very moist and
unstable through the period. Precipitable water values range from
1.75 to 2 inches this afternoon and will increase to over 2 inches
on Friday. As a result, heavy rain is to be expected with any
convective activity that occurs. Widespread flooding concerns are
not anticipated, but if localized flooding is nonetheless possible
if cells train over the same area or if slow-moving cells remain
over a location for a prolonged amount of time. Furthermore, while
convection will diminish in coverage with the loss of diurnal
heating, the deep moisture could allow for some thunderstorms to
remain well into the night tonight and tomorrow night.

Good instability is in place this afternoon, with mlcape
values of 2000-2500 j kg, along with SBCAPE of 3000-3500 j kg and
dcape of 750-100 j kg. While mid-level lapse rates are progged to be
marginal at around 6 to 6.5 c km , it is possible that the shortwave
dropping southeastward through the area could enhance the lapse
rates higher than anticipated. Mid-level lapse rates are anticipated
to be slightly steeper tomorrow. As a result of these factors, it is
possible that a several storms each day could become strong,
producing gusty winds, frequent lightning, and heavy rainfall. An
isolated severe thunderstorm cannot be ruled out, as well, with
damaging wind gusts being the primary hazard.

High temperatures across central georgia will be 3-5 degrees above
climatological normals this afternoon, in the upper 90s. Dewpoints
in the upper 60s and low 70s across the area will contribute to heat
index values between 100 and 104 across east and central georgia,
but it does not appear that heat advisory criteria will be met this
afternoon. Higher coverage of convection and cloud coverage are more
likely to keep temperatures in check across the area tomorrow. High
temperatures tomorrow are thus expected to be near average across
the area, mainly in the low 90s. Dewpoints, however, will also be
higher across the area, leading to heat index values over 100 and
approaching 105 in some areas. These heat indices will need to be
monitored in ensuing forecasts as only a minor increase in
temperatures or dewpoints could lead to heat advisory criteria being


Long term Saturday through Thursday
Guidance has been very consistent over the preceding days, and
therefore, only minor tweeks have been made to the long term
forecast. The previous long term forecast discussion continues to be
valid and is provided below...

prev discussion... Issued 337 am edt Thu jul 18 2019
the long term portion of the forecast begins late on Friday with
high pressure situated just to the west northwest of the local area
with an area of lower pressure in the vicinity of the southeast that
will persist through the weekend. Models are showing differences in
location, but overall impacts will be similar through the fist half
of the extended with plenty of moisture in the lower levels of the
atmosphere. This will allow for chances for showers and
thunderstorms daily with the best chances coverage in the afternoons
and evenings. At this point, have included likely pops across much
of the area on Saturday and chance pops across the area on Sunday
with an area of likely pops across the northern tier. With moisture
continuing to advect into the area, higher coverage of showers and
storms is expected to continue on Monday as well. Likely pops have
been included across the northwestern portions of the area with
chance pops elsewhere.

By late Monday to Tuesday, a front will push into the area
continuing to enhance chances for rainfall across the area and
dropping temperatures to just below seasonal norms. As that front
approaches and enters the area, pwats are expected to rise to around
2 inches increasing the potential for heavy rain. Likely pops have
been included for Monday through Wednesday in the afternoons and
evenings with the highest pops across northern portions of the area
before spreading southward as the days go on.

High temperatures through the weekend are closer to seasonal norms
with cooling trend after the weekend through the first half of the
work week. Overall, high temps are expected to be in the mid-80s to
mid-90s. Overnight low temperatures through the extended will be in
the mid 60s to mid 70s.


18z update...

scattered convection is ongoing across north georgia, particularly
near the metro area, and is beginning to develop across central
georgia. Tempo for tsra is in place starting 18-19z at the metro
sites and ahn, and slightly later starting at 19-20z at csg mcn.

Cu field at 035-050 is in place to begin the TAF period, although
tsra could introduce some high-end MVFR ceilings, as well.

Convection is expected to linger into the overnight hours, so have
maintained vcsh until 04z as a result. Winds throughout the period
will be mainly w, at 7-10 kts this afternoon before diminishing to
5 kts or less overnight, with the only exception being any gusty,
variable winds associated with tsra.

Atl confidence... 18z update...

medium confidence on timing and locations of tsra.

High confidence on all other elements.


Preliminary point temps pops
Athens 74 93 73 92 30 50 40 50
atlanta 75 91 74 89 30 60 40 60
blairsville 67 86 68 84 20 50 30 60
cartersville 73 91 73 89 30 50 30 60
columbus 76 92 74 91 30 60 30 60
gainesville 73 90 73 88 30 50 30 50
macon 75 94 73 93 30 60 40 50
rome 72 92 73 90 30 50 30 60
peachtree city 74 91 73 90 30 60 40 60
vidalia 75 95 75 94 30 50 30 40

Ffc watches warnings advisories

Short term... King
long term... .Thiem
aviation... King

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Marietta / Dobbins Air Force Base, GA6 mi82 minSW 10 G 2210.00 miThunderstorm Light Rain79°F68°F70%1017.4 hPa
Cobb County International Airport - McCollum Field, GA7 mi28 minNNW 310.00 miFair76°F72°F88%990.4 hPa
Atlanta, De Kalb-Peachtree Airport, GA12 mi25 minWSW 610.00 miPartly Cloudy80°F70°F71%1016.5 hPa
Fulton County Airport-Brown Field, GA15 mi25 minWSW 510.00 miLight Rain78°F71°F79%1017.1 hPa
Cartersville Airport, GA22 mi25 minN 010.00 miFair77°F71°F82%1016.6 hPa
Atlanta, Hartsfield - Jackson Atlanta International Airport, GA24 mi26 minN 010.00 miOvercast78°F73°F85%1017.4 hPa

Wind History from MGE (wind in knots)
Last 24hrW6SW4W4SW4SW3W4CalmCalmCalm--CalmCalmW4NW3S2W6W7W5W13NW8NW11W10SW10
1 day agoSW7SW7S5S4S3S3----SW3--CalmCalmCalmCalmW3W5W7W4SW9SW12
2 days agoW10

Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of Southeast    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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Wind Forecast for Peachtree City, GA (17,4,5,8)
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Ground Weather Radar Station Atlanta, GA
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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.