Winning The Fishing Gamble During Cold Front Season

If your fishing travel takes you to the southeastern US, the northern Caribbean or to the Bahamas during the winter months, chances are you have had at least part of one or more trips ruined by the sudden appearance of a strong cold front. Likely as not, you have had an entire trip ruined by high winds, plummeting temperatures and scudding clouds. The experience is disheartening to say the least.

Normally, there is not much one can do about this kind of thing because bookings are usually made months in advance. And there is usually a good reason for making advance bookings. Quite simply, if you don’t book ahead of time, there is a real chance that space at your favorite lodge or time with your favorite guide will be unavailable. That’s particularly true as regards rock-star redfish guides in Louisiana during the height of the big-fish season. The same is true of some permit lodges in Belize and bonefish lodges in the Bahamas.

Right now, however, with the US economy still shaky, most lodges and guides are dying for bookings. Almost certainly, if you have a flexible schedule, you will be able to find prime space and time available this winter at the last minute throughout the region that is adversely affected by cold fronts. Actually, given the amount of pain out there, you may even be able to arrange a special last-minute discount. The real pay-off in arranging a last-minute trip, however, is not saving a few bucks. The pay-off is increasing geometrically the chances of avoiding a trip-ruining cold front. In effect, if you follow my advice in this report, you will reduce the element of blind chance in your trip planning this winter. Yes, a last-minute plane ticket might cost more, but who wants a cheap ticket to possible cold-front hell?

Consider for a moment just what cold fronts are and how they behave. Throughout the winter months, cold fronts are climatologically on average a weekly event along the entire Gulf of Mexico coastline, as well as throughout all of Florida and the Bahamas. During particularly intense mid-winter periods they may come as often as every three to five days. The stronger fronts frequently reach as far south as the northern Caribbean and the Yucatan Peninsula, and sometimes all the way down to Honduras. These stronger fronts typically occur two or three times a month, especially during January and February.

Meteorologically speaking, a cold front is a sharp boundary between warm air on its south side and cold air on its north side. Typically, we have to deal with three unpleasant events with the passing of a cold front: strong southerly winds ahead of the front; a squall line that often has strong, shifting winds and heavy rain as it passes; and then strong northerly winds immediately following.

The stronger winds ahead of the front and the attendant squall line may pass in a matter of hours, but if the air mass behind the front (which appears on the weather maps as a HIGH) is large and has a tight pressure gradient (the lines representing pressure are close together), strong northwesterly winds will follow immediately behind the front and then gradually swing all the way to the northeast or east. These winds will blow 15 to 25 mph for days.

Unfortunately, the misery doesn’t end there. The cold winds following the front will also cause rough seas and a sharp drop in water temperature, sometimes as much as 10 to 15 degrees F. in inshore waters in less than a day. If these chilly winds keep blowing for several days, the water temperatures keep sliding downward, too. It doesn’t take much to put tropical and subtropical shallow-water game fish off their feed. Tarpon, for example, prefer 75 to 92 F. and they disappear quickly if it goes below 70 F. They also disappear if it gets too windy. For bonefish, the optimum temperatures are 72 to 86 F., and permit 74 to 85 F. Snook like it best when the water is 70 to 82 F., redfish 64 to 92.

In a side note here, I should point out that many fish do adjust to cold temperatures. After water has been unusually chilly for several days, bonefish, permit and snook will often begin to show up in water as cold as 62 F. provided the winds are light. Redfish will show up in water even a few degrees colder than that. Tarpon have even been known to start feeding at just below 70 F. after a prolonged cold spell, as long as the winds are light and forage abundant.

Fortunately for us anglers, not all cold fronts are created equal. Some are strong, and some are so weak they pass with little effect. The factors that determine strength are the size and origin of the air mass behind it and the front’s forward speed. A rapidly developing low pressure system along any front can also increase both forward speed and intensity.

The strongest fronts are those with a large mass of Arctic air behind them as they dive at express-train speeds southward out of Canada. They cause strong winds and a rapid drop in air temperature of 20 degrees or more as far south as the Bahamas, and it usually takes three to six very windy days for things to even begin to calm down and temperatures to rise significantly.

Those fronts with a large maritime air mass from the northern Pacific Ocean behind them can also generate a lot of wind and they can cool water temperatures somewhat. Their air temperatures tend to be not nearly as chilly, however. They can make it windy for several days; and, during that time, water temperatures only recover slightly. But often areas protected from those winds remain very fishable.

The least obtrusive cold front has a very weak, only slightly cooler air mass behind it. This kind of front moves slowly, generates little wind and bad weather. This type also often stalls around the middle of the Florida peninsula and may sit for days before finally disappearing completely. The area south of that front typically enjoys light winds, summer-like weather and great fishing.

The trick, of course, is figuring out what type of front is coming and when it will get to where you intend to be – if it gets there at all. Currently, the best answers are found on a website maintained by the National Weather Service Hydrometeorological Prediction Center. This site provides, in graphic form, sea-level pressure and cold/warm front information for up to seven days in advance. It is very easy to use.

The website is located at http://www.hpc.ncep.noaa.gov/. This center issues new forecast maps twice daily at 5 am and 5 pm Eastern Standard Time. When you visit the site, you will see a screen with a series of nine thumbnail-size maps. Below the top row of three maps there is the link called: “Loop of sea-level pressures and fronts through day 7.” When you click on this link you will see a series of animated maps that will take you through all seven days of the forecast period.

Once the animated maps have completely loaded, I find it helpful to click on the Stop button and then step through each map one at a time. That way I can see at my leisure the predicted advance of any cold fronts and get a general idea of how strong they are likely to be throughout the seven-day forecast period, how fast they are moving and how far south they will go. See the illustration on page one of this newsletter for a sample map, taken directly from the National Weather Service web site.

The movements and sizes of the various HIGHS (H) and LOWS (L) are easy to follow on the site. Keep in mind that those cold fronts oriented closer to a north-south line tend to move more rapidly than those oriented more along an east-west line. A front oriented entirely east-west moves slowly and is very likely to stall.

In the illustration on page one of this newsletter (a Day 7 forecast map dated December 3, 2009), we see a cold front of moderate strength and speed (it’s oriented NE-SW) pushing past the southern tip of the Florida peninsula. The close proximity of the pressure lines on the north side of the HIGH indicate a lot of wind, but on the south side they are spaced much farther apart and the expected winds will be moderate out of the northeast. As for determining wind direction, remember that in the northern hemisphere the wind always blows counter-clockwise around LOW pressure and clockwise around HIGH pressure.

Note that while this map covers all of Florida, as well as most of Cuba and the Bahamas, it does not extend southward as far as the Yucatan. If you want to see how those areas are going to be affected by frontal activity, there is another series of charts on the same NWS page that will help. Click on the map thumbnail labeled “Day 3-7 Forecasts” and you will see another series of six thumbnail maps. The one you want is labeled “Days 3-7 (US only) [b/w].” Clicking here will reveal a series of five maps covering the forecast period, each of them extending southward all the way to Honduras and eastward past the tip of Cuba.

I’ve been using these NWS 7-day forecast maps to plan my own fishing trips for four to five years now, and I find they are surprisingly accurate in predicting the approximate locations of the fronts. As you would expect, as you go further out in the forecast period, the accuracy decreases somewhat; the forecast for Day 1 is always going to be better than the forecast for Day 7. So while the system is not perfect, it IS much, much better than simply picking the most convenient dates for a trip well in advance and hoping for the best. Over the years this system has saved me from many otherwise bad days on the water.