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A user friendly tutorial for self-briefing and forecasting marine
weather conditions including radar, satellite imagery and local marine
observations.
With the approaching holiday season, angler’s can now expect to
experience the effects of dreary, early winter cold fronts. These
unstable late season weather patterns are generally transitional fronts
which luckily, often lose their strong southeastward surge as they make
their way towards South Florida and adjacent coastal waters. When these
fronts do make their way south and past Lake Okeechobee, they will
usually stall over the Straits of Florida before backtracking across
the State as a more suitable warm front.
These early season cold fronts can pack a punch and are often accompanied by weather fluctuations that may be quite intense, though usually brief. The most common fluctuations are known as pre-frontal squall lines. It’s not uncommon for mariners to see the tops of these approaching squall lines from as far as 100 miles away.
Once a front returns north as a warm front, it will usually have a much broader boundary and will usually move much slower. Reading the clouds accompanying these warm fronts will likely be more difficult as the lower clouds are stratified and accompanied by light rain or drizzle and fog, camouflaging the embedded heavy showers and thunderstorms.
Even though these warm front convective clusters move slower, they can still produce locally gusty winds that can quickly turn ocean into a monster. They may also spawn extremely dangerous cloud to water lightning. Because these storms are slow moving as they continually develop while tracking along the same path (train-echoing), heavy rain may persist in the same general area for extended periods of time. This may result in large rainfall amounts that may eventually overcome weak bilge pumps, particularly on moored or docked boats.
If for reasons like this, that mariners, like aviators, need to be in tune with the weather. Here are a few simple steps that will turn your PC or laptop into a full weather station so you can prepare a thorough briefing and forecast for your specific area. Although I will demonstrate using the concept of briefing yourself before a fishing trip, there is no reason that you can’t have these easily updatable “loops” running full time in your office, bait & tackle shop or marina. Over time, you’ll become the most reliable weatherman you’ve ever met!
This will work from any Coastal National Weather Service Office homepage, but I will use the Miami office which covers South Florida for this demonstration. Using your favorite browser go to the National Weather Service Miami Forecast Office homepage at
http:// www.srh.noaa.gov/mfl.
Scroll down in the left margin to ‘Radar Imagery’ and select Miami. Naturally, Miami is the default radar location on this site. Select ‘Surrounding Radars’ for other Florida radar sites or the ‘Nationwide’ option for the remainder of the continental United States.
The default radar image is the latest single frame of ‘Base Reflectivity’. Base Reflectivity data contours and shades the differentiating rainfall rates corresponding to the intensities of the rain cells. On the left margin, below ‘Base Reflectivity’ and just to the right of ‘Short Range’ select ‘Loop’. This creates a 30 minute animation of base reflectivity. This is high resolution imagery good for a range of 124 nautical miles from the actual radar antenna. The Miami radar antenna is located in Richmond Heights (near Metro Zoo), in Miami-Dade County.
Note that you are provided with tools to stop the loop, adjust the looping rate, rock the loop back and forth and most importantly, to zoom or un-zoom the loop or a single picture. Experiment!
Now let’s make some adjustments. On the left margin, under ‘Base Reflectivity’, select ‘Loop’ to the right of the ‘Long Range’. This will load a 30 minute looping sequence of 6 minute scans as before, but now the resolution will be greater, enabling you to see 248 nautical miles from the radar antenna. This range extends across the northwest Bahamas, most of Cuba and the Dry Tortugas. By now you may realize that you prefer the Key West radar station in order to see further south into the Straits of Florida or the Tampa Bay radar to peek further west into the Gulf of Mexico.
Be aware that at the edge of the display in these extended ranges, the center of the radar beam is roughly 50,000 feet or about 9 miles high. So if you see precipitation at that range, it’s safe, under most atmospheric conditions to assume that these are intense thunderstorms. On the other hand, just because you don't see radar echoes at these long ranges doesn't mean it isn't raining at that location. The radar beam could be shooting above rain showers which are capable of producing heavy rains, reduced surface visibility, squally winds, disturbed seas, dangerous cloud to water lightning and even waterspouts.
Next, notice the ‘Adjacent Radars’ box at the top left of the display. The arrows will set up loops for each of the surrounding radar sites using the display parameters that you last selected. Perhaps your fishing trip will be near shore in the coastal waters outside of Government Cut in Miami, a favorite place for kite fishing. This location would be quite close to the Miami radar antenna and radar clutter may obstruct developing showers over the area. These showers might move or propagate east across the near-shore coastal waters. In this situation, I would suggest that you view the Key West radar as it has an un-obstructed view of convection over Miami. But remember that the Key West antenna is about 130 nautical miles from Miami (as the frigate bird flies), and the antenna beam may be overshooting showers that are just forming. This leads to the next step in preparing a self-briefing for your trip, the simultaneous use of animated satellite imagery.
Leave your radar loop running but minimize the browser. To update the loop all that is necessary is to select the refresh on your browser. Open up another browser window. Again start at the Miami Forecast Office home page http://www.srh.noaa.gov/mfl
Scroll down on the left margin to ‘Current Conditions’ and select ‘Satellite Images’. Since most fishing trips start early in the morning prior to sunrise you will have little choice but to use ‘Infrared’ imagery. So select the center satellite image.
Now you will need to customize your satellite loop. Select ‘Animation’. Satellite imagery is normally down-loaded and ingested every 30 minutes but satellite downloads can be programmed to 15 minute intervals during critical weather episodes. Usually, you can safely assume that it will take 2 frames per hour when determining your loop length. For example, you are aware a cold front is approaching from the northwest across the Gulf of Mexico and you would like to estimate how many hours that you will have before the pre-frontal squall line and associated wind shift arrives. In this case you might select 25 frames for a solid 12- hour loop. I suggest leaving the remainder of the parameters at their default values for faster downloads but don’t hesitate to experiment with faster internet connections.
But, before you click on the ‘Animate Image Below’ tab, click on the image in the area where you wish to zoom. You will have a color enhanced satellite loop to compare with your radar loop and can now view activity beyond the radar range. Use the satellite image to view what's going on over the larger cities like Miami where ground clutter may contaminate the radar data. This often occurs at night when there is a cooling difference between areas of rapidly cooling cleared ground, areas of heat retaining concrete and areas of rain soaked land from recent late afternoon showers. Also, the military occasionally drops training chaff in the Straits of Florida and in the Florida Big Bend area that shows up on radar but will not show up on satellite imagery.
Try the visible imagery at high resolution during daylight hours and you will see the smallest of rain showers as they develop. You can also see the afternoon sea-breeze front on visible satellite imagery. Visible imagery will likely be the best choice during the afternoon when preparing for a night sword trip. Minimize this second browser as well. Again “refresh” is all that is needed to update the satellite loop.
Finally, open a third window to the same site (http://www.srh.noaa.gov/mfl). Scroll down on the left margin to ‘Current Conditions’ and select ‘Observations’. ‘Observations’ will display the current weather conditions across South Florida in a table format. Included will be air temp, sea temp, wind speed and direction. Note that the marine observations from the Coastal Marine Automated Network (C-MAN) are displayed, with a link to the NOAA National Data Buoy Center interactive sire (NDBC) at http://www.ndbc.noaa.gov/Maps/Florida.shtml.
Linking to the NDBC page and selecting a particular platform will provide you with the exact GPS location of that platform and will list the height of the anemometer along with other platform details. As an example, select ‘Fowey Rocks’ in the Marine Observations box. You will notice the wind observations for the past hour are listed at 10 minute intervals. Additionally, complete observations for the past 24 hours are also present. Glancing through this table could help you determine if localized showers are causing temporary gusty winds or if a synoptic weather feature is the mechanism and therefore the wind direction and intensity are going to be more persistent. You can minimize this browser as well and use your refresh tab to update.
I set up these loops on my home computer the night before a fishing trip. The data is down-loaded once and the loops are set up. Your screen saver will come on during the night and your computer will go into hibernation or some sort of power saving mode depending on how you have it set up. The DSL or modem connection will usually remain established. When your alarm clock rings at oh-dark thirty, just walk over to your computer and hit refresh in each browser window. The updated loops will download in a minute or so. If the Internet connection is lost, just re-establish it without touching the minimized browsers. You will then have up to the minute weather information which will help you make decisions on whether to run north or south or whether to trailer your boat to Biscayne Bay or Everglades City. Of course if it looks really bad weather wise, you can just crawl back under the covers with the misses.
When in route to your boat or once on the water, another useful way to retrieve marine observations and the latest marine forecast is to program your cell phone with the Dial-A-Buoy number at (228) 688-1948. Program your cell phone with this number for each buoy and C-MAN platform that you may fish by. Store each under its unique five-digit or character station identifier. This way the station identifiers will display on your phone’s screen when you make the call.
When you dial in, press ‘1’ and you will be prompted to enter the station identification followed by the # sign. Characters are entered by pressing the key containing the character. For example, the station identification for Fowey Rocks is FWYF1 or 39931 followed by #. You will hear a computer generated voice of the latest hourly buoy or C-MAN observation. After the latest hourly observation is read, the computer will prompt you for the corresponding National Marine Forecast for that station location. When you are finished, you simply hang up.
Thanks to modern day technology, coupled with a bit of practice and experimentation, NOAA’s internet weather sites provide boaters with the latest invaluable information to help you decide if rain gear or extra sun screen is on the agenda for the day.
Be safe and go get ‘em!
Captain Martin Nelson grew up in South Florida.† He was first certified in scuba in 1972, and has since logged thousands of dives both recreationally and on the salvage boats working the 1715 Silver Plate Fleet off the Treasure Coast.† He is a past member of both South Florida Divers and the Miami Sport Fishing Club.† Martin has been a professional meteorologist for over
25 years.† His meteorological career began in the US Army and he has worked in every aspect of operational meteorology including weather radio broadcaster, observer, weather balloon and radar operator, and as a public, marine and aviation forecaster.
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