I’ve been brushing up on my meteorological skills over the past couple of days. “Burshing up” being secret code for getting any meteorological skills since up to this point I have had none. But what I have had is this phone with a ton of apps that tells me exactly what is going to happen weather-wise and it is always correct!
Actually, these apps are 100% correct in that there will be actual weather, but the variability between forecasts in the different apps is often quite large and the variability between any given weather app and the actual, you know, weather, is also greater than zero. Much greater some days.
Why we are thinking about this now is that we are sitting in Marathon waiting for a ‘weather window.’ A mythical thing, elusive and rare as leprechauns and unicorns. And to someone on a boat who doesn’t want a rocky holiday season, just as treasured.
Christmas has passed and now we are ready to move on to the next part of our journey, which we hope is the Bahamas. But we have to get there. Distance wise, it isn’t all that far. From where I sit and type this, it is just over 100 statute miles; so we could do an overnighter and get there. Or we could move up to Key Largo and cut NE from there and the distance is down to under 60 miles. A distance we have done many times on this trip and can be done in the daylight. Especially since, for both trips, we get the benefit of the Gulf Stream.
We are and have been familiar with the Gulf Stream. But ours was a ‘theory’ kind of familiarity. We knew, for example, that it brought warm water up the East Coast, right by Ocean City, MD where we had our condo, and it warmed the water, even when it was cold outside. And we knew that when we lived in Germany and marveled at how warm it was in the winter (relatively speaking, of course), it could be somewhat attributed to the Gulf Stream (called the North Atlantic drift at that point).
Now we are in the process of getting a more practical application. The Gulf stream is a couple of miles off shore from where we sit, and clipping along at a good 3-5mph from south to north. Which is fantastic since that is the way we generally want to go! The distance it is from shore varies, and is part of the forecast for the area. The practical application is two parts.
First is route planning. Since the current is so fast, especially compared to the speed of our boat (think ‘turtle’ in the ‘turtle and hare’ story), we have to take into account the push north. If we don’t and we just set our sights to our destination, the Gulf Stream will push us and we will find ourselves north of Bimini by 10-20 miles. If you look on a map, there isn’t a lot there. And it would be a long trip back south. If we try to keep ourselves on a heading directly to Bimini by turning the boat against the current, our course made good will go to zero. So we plan to aim for a spot 20 miles south of Bimini and let the current do the work.
The second part is in the timing. As we have learned on this trip, when current and wind are against each other it is a recipe for very uncomfortable conditions (i.e. ‘big waves’). Any inlet that we have been through on this trip we try to make sure that the wind and current agree and hold on if they don’t. Now imagine the scenario where they don’t agree–but on steroids. Like Lyle Alzedo. That is what happens if the wind comes anywhere out of the north, against the Gulf Stream. Really big waves.
So we sit. And watch the weather forecast. And subscribe to newsletters, message boards, twitter feeds, anything that has to do with weather window. And wait for a time where there isn’t a north wind.
Apparently people have spent months in the winter waiting or a weather window, or get frustrated and just don’t go. Because, as it turns out, there are lots of north winds this time of year because it is WINTER! What we want is something with a South in it. BUT if there is a South in it, it means a front is on the way and the wind is tracking around (SE to S to SW to W to ‘Hold on to your hat it is going to get ugly’ as it gets back to N). Trick is to find a slow moving front or maybe one that has stalled that gives you a break. Or no wind and motor like a banshee to get a cross.
All of this has us focused on weather. Not just four or five days from now, but each day. And we have noticed a trend.
Here in Marathon, FL, middle of the Keys, there is a daily 10% chance for rain. But up to recently that 10% has not materialized into anything at all. Just gorgeous, sunny days. But lately that 10% chance of rain has been a 100% chance of rain at 2 in the morning. I’ll get back to that in a minute and why that matters. But first, I did a little research on weather.gov (because neither internet nor or government lies).
What I found was that the Percentage of Precipitation (or PoP) is defined as follows:
******WARNING MATH AHEAD!!!****************
PoP = C x A where “C” = the confidence that precipitation will occur somewhere in the forecast area, and where “A” = the percent of the area that will receive measurable precipitation, if it occurs at all.
That wasn’t so bad, was it?
So if weather dude is 100% confident that we are going to get rain somewhere and he/she thinks that it will cover 10% of the forecast area, the PoP is 10% (1 x .1=.1 or 10%) Or if he/she is 50/50 on the whole rain/not rain thing, but if it does rain it is going to hit everyone, then PoP=50%. Easy Peasy.
Our forecast, as mentioned above has been 10% PoP. And in our experience, that 10% chance of rain means it is going to be nice weather for 22+ hours out of the day,1 but in the dead of night, when we are in the sweet spot of sleeping, the rain it starts to pour.
So why is this a problem?
The temperatures here are the high 70s/low 80s here in the day time with 70-80% relative humidity.2 Warm and humid but not deathly so. At night we get down to 70. Usually not much lower. And still the humidity. But there is a breeze. So our windows are wide open to catch the breeze and we have a very comfortable night of sleep. Every night there are 14 windows that are open.3 Eight of them can be closed from the inside, four of them can be closed from the inside, but it takes some work (and these are directly above our beds) and four must be closed from the outside. Which means that at 2am when we feel rain splashing on our faces, we leap out of bed, trip over the dog, drop the screens from the windows above our bunks onto our heads, curse, and close the windows and then run around the boat closing the rest. With one of us *cough* Jim *Cough* heading outside into the rain to close the remaining four windows.
For one night, no problem. Sleep in a bit more in the morning. Two nights? Aggravating but still ok. Three nights? Ouch. Crankiness abounds.
Large quantities of coffee in the morning and we check the weather once again, looking for our weather window to move on to the next part of the journey.
1 I acknowledge that there are people out there reading this that live in a part of the country that don’t have nice weather this time of year. Like at all from December to March. And that my whining about getting rain at 2am probably falls on deaf ears.
2 Again…apologies to those of you from the north land that are still reading. Though you really have to start thinking about taking some time off and heading south in the winter. I mean this is pretty sweet! Seriously. I do like winter and snow and skiing, but doesn’t it get to be a bit much after 6 months???
3And why can’t we keep them closed? We do have air conditioning, but we need shore power or generator to run that thing and we have been at a mooring ball for 10 days now; no shore power and we don’t need to run generator. So no AC. We could keep them closed when we go to bed, but it turns our that with high humidity and moderate (not cool) temperatures outside, if we keep the windows closed, our boat turns into an environment more akin to a tropical jungle.