Saturday, July 31, 2010

Man the Pumps

Here in Guatemala we are finally getting a proper rainy season. There is some rain every day, occasional heavy rain, and thunderstorms almost every day. Here in Rio Dulce in the past 12 hours we got a lot of steady heavy rain. The main cause for this is a continuous series of tropical waves and moist air coming off the coast of Africa, crossing the Atlantic and Caribbean, and arriving here in Guatemala.

From time to time, a combination of waves, moist air, and sometimes an upper level trough (check your 500 mb charts) will result in more intense weather. Such a configuration is on its way and looks like it will arrive Monday night.

Since this is the tropics and conditions are unstable it's impossible to make solid predictions but what's approaching us is a wave embedded in a high amplitude moisture maximum with moderate to strong convection. This feature could bring very heavy rains (5 to 10 times what we've been getting daily) Monday night, Tuesday day, and Tuesday night.

Monday, July 26, 2010

Torito, Feria de Rio Dulce







Saturday, July 24, 2010

Marching Drummers, Rio Dulce Feria, April 2010







Friday, July 23, 2010

Tropical Storm Bonnie

Location: 24.7N 79.8W, 80 mi SSE of Miami, 75 mi E of Marathon, FL
Movement: WNW at 16 kts.
Minimum central pressure: 1008 mb
Max sustained wind: 35 kts, gusting 45 kts

Tropical Storm Bonnie is loaded with moisture and has good outflow. Computer models project the path as pretty much a straight line across the Florida Keys and to the Mississippi Delta / New Orleans.

BP is evacuating the site of the Macondo well blowout because the projected path goes right through there.

Thursday, July 22, 2010

Tropical Storm Wastes No Time

Early this morning it was a disorganized mass of thunderstorms. Then the circulation closed and it became Tropical Depression 3, discussed in this post.

This afternoon it strengthened and has now become Tropical Storm Bonnie. Here's the data right now:

Location: 22.9N 75.4W, 200 mi SE of Nassau, 415 mi ESE of Key West.
Max sustained wind: 40 MPH
Min. central pressure 1005 mb
Movement: NW at 14 MPH

Projected path takes it on a straight course over the Florida Keys and towards Lousiana.

Desfile de Los Vaqueros, Feria, Rio Dulce, 16Apr10





It's a Zoo Out There

All kinds of things are happening in the Atlantic, Caribbean, and Gulf of Mexico. A couple of days ago I mentioned a disorganized area of thunderstorms over the Leeward Islands that appeared likely to organize and it has done so. It is marked in red on the image below. The system now has closed circulation and is being assisted by a high over the Bahamas. It's expected to become a tropical depression later this morning and seems likely to be the first storm of the season to affect south Florida.

Around midnight last night we got clobbered here in eastern Guatemala by a two hour thunderstorm that brought a huge amount of rain. This was the result of another tropical wave that passed us combined with the influence of a low located in the Bay of Campeche that is affecting a very wide area including eastern Guatemala. This 1008 mb low is marked in orange on the image below and shows signs of development. It will move slowly away from us and so is not a threat but it's likely to bring us more rain.

Lastly there is another tropical wave packed with moisture coming. Presently located at 82W, it should reach eastern Honduras by tonight and affect us possibly tomorrow (Friday) and Saturday.

For a complete weather overview including temperature and precipitation forecasts, all on one page: Tropical Weather

Tropical Rain




Wednesday, July 21, 2010

Waves and More Waves

At this time of year, during the rainy season in Guatemala, or "invierno" (winter) as it's locally called, we get tropical waves that produce rain. One after another they are coming now.

Last night we got a good amount of rain and more is coming. Another tropical wave loaded with moisture is located around 87 degrees west and is coming to us and there's another one behind that. We might get a little break in the rain during the day today but another mass of moisture looks like it will arrive late this afternoon.

We appear to be getting a normal rainy season, which is a welcome relief after the 19 month drought we just had. In 2009, our rainy season failed to occur. So for those of you who have been here less than two years, what we're having right now is normal. If you haven't bought an umbrella yet, you might consider it. If all goes as expected, the weather we are getting now will continue into October and possibly early November.

Tuesday, July 20, 2010

Rain in Our Future

Two tropical waves are affecting us here in Eastern Guatemala right now. One just passed us and another is over eastern Honduras and approaching at 15 kts. Both waves have air masses associated with them that are loaded with maximum moisture. So expect intermittent rain and possible thunderstorms over the next few days.

The forecast for Eastern Guatemala indicates a moderate amount of rain (about 10mm) each day for the next several days, although heavy downpours are always possible because the air is so unstable.

Out over the Leeward Islands is an area to keep an eye on. Shown circled in the image below is a large area of disorganized thunderstorms that is showing rotation and circulation. There are no significant features around that system that would inhibit outflow so it's probably going to develop.


Friday, July 16, 2010

Unstable Air Today

The air over Eastern Guatemala is very unstable today so clouds / rain / thunderstorms can develop in a heartbeat.


Bring your umbrella!

Thursday, July 15, 2010

More Moisture Coming To Guatemala

It appears that the moist air mass mentioned in the previous post (#2 in the image) is becoming more active due to interactions with a ridge. This moist air was expected to bring rain for this weekend, mainly on Sunday, and now convective activity is increasing.

There's a small but non-zero probability that the mass could start rotating. If that happens then the system will throw moisture out over a much wider area and it could develop into a tropical storm, so it's something to keep an eye on because it's quite close and will likely bring significant rain this weekend.

The region marked #1 in the image started to get interesting early this morning because it has a good chance for development but it's far away and not a worry to Guatemala at this time.



Monday, July 12, 2010

Five Day Outlook from Rio Dulce

After the passage of the last tropical wave, here in Eastern Guatemala we are now in the midst of a moist unstable air mass that is causing intermittent rain and thunderstorms. We have about one more day of this before the next tropical wave arrives.

The next wave is located at 85W right now and marks the trailing edge of the moist air mass we are in. Behind that wave is a drier Saharan air mass which should bring drier days for Wednesday, Thursday, and Friday. Then behind that is another wave followed by moist air that should bring significant amounts of rain on Saturday and Sunday.

Sunday, July 11, 2010

Low-Pressure System off Pacific Coast of Guatemala

An area of low pressure and disorganized thunderstorms has formed off the Pacific coast of Guatemala. There is a chance this could develop into a cyclone but should not be a direct threat to Guatemala because it's moving west or northwest. However, if a circulation gets going the system could produce increased rain over Guatemala.

Saturday, July 10, 2010

Wet Air Mass Arriving

I've been observing a strong tropical wave that's been approaching for the past four days. Along with that wave and trailing behind it is a large airmass that's loaded with moisture.

The wave should be passing over us here in Izabal this afternoon (Saturday). Pressure in Rio Dulce right quite high at the moment, 1016 mb, and we should see the dip when the wave gets here. I'm guessing the leading edge of the moisture will get here around 2 or 3 PM. This airmass should usher in a period of about six days of intermittent rain averaging 1/2 to one inch of rain per day.

Friday, July 9, 2010

La Niña Is Forming as Expected

Strong effects are more likely to be predictable and that appears to be the case right now. We had a strong El Niño (El Niño-Southern Oscillation) that began in 2009 and ended, as predicted, in April of this year. After a strong El Niño we usually get the opposite phenomenon nicknamed La Niña. I discussed this back in January / February and it appears that this is now occurring.

El Niño is the name given to an oscillatory phenomenon that affects the sea surface temperature in the equatorial eastern Pacific Ocean. During an El Niño the sea surface temperature in the eastern Pacific rises above average, which causes changes in weather on a global scale, but the strong effects mainly occur in the Western Hemisphere. Some regions become drier and some wetter, some places get heavy weather, others get milder weather.

Generally speaking, during an El Niño, Atlantic hurricanes are usually suppressed and North America receives heavy precipitation and a heavy winter, and this did occur in the winter of 2009-2010. Nobody in Washington, DC could remember the last time there was a 3 foot snowfall. In Guatemala, our rainy season was much weaker than normal and we had a long hot dry summer. This occurred in 2009 and into 2010 where we had drought conditions and for 18 months here in Rio Dulce and across most of Guatemala, we only received one sixth the normal amount of rain. As much as 80 percent of the crops were lost in 2009.

Now the pendulum is swinging the other way. Sea surface temperatures in the eastern equatorial Pacific Ocean are plummeting and will probably plunge up to 5 degrees C below normal. We are heading into a La Niña condition, probably a strong one, and that will likely spell troublesome weather for Guatemala and the Caribbean.

In 2009 we got a free-pass on hurricanes. Thanks to El Niño hardly any hurricanes occurred in the Caribbean. A La Niña brings the opposite and we need to expect and prepare for more hurricanes than usual and stronger hurricanes. We have to expect above normal rainfall which brings the hazards of flooding and landslides. And we have to keep closer watch on the weather because during a La Niña, the weather changes more quickly and tropical cyclones can develop much more quickly.

Let's hope the rain comes slow and steady so it refills the aquifers and not in monster downpours that create big runoffs, flooding, destruction of crops, and loss of topsoil.

Thursday, July 8, 2010

Prepare for Rain!

It looks like we're in for a week of rain. There is a good chance of rain every day and night through at least Wednesday. Heaviest rainfall periods are expected on Saturday day, Monday day, Monday night, Tuesday day, Wednesday day, and Wednesday night.

There are many tropical waves that have been passing over us and more are coming. They're coming off of Africa one after another. The heavy rains that are expected to begin on Saturday result from a wave expected to arrive at that time. Behind that wave is a large mass of air carrying a "maximum load of water". In other words the water imagery shows this air mass is loaded with the greatest amount of moisture that the air can support, hence the high chance of rain.

Note: The heavy thunderstorms we got all night last night here in Rio Dulce are the result of the tropical air mass I wrote about here: Possible Weather Developing which did not develop while it was north of Honduras. Instead, this large area of disturbed tropical air moved northwest, across the Yucatan, and into the Gulf of Mexico, where it has developed into a tropical depression. This system has very broad circulation and our storms last night were related to this tropical depression now up in the Gulf.

Wednesday, July 7, 2010

Rain in the Forecast

If you have plans for the weekend, you might consider the following: The weather forecast for eastern coastal Guatemala shows a slightly increased chance of rain today (Wednesday), Thursday, and Friday. However heavy rain is forecast for Saturday and Sunday, day and night, and into part of Monday. 30 to 50 millimeters of rain is expected each day.

Sunday, July 4, 2010

Developing Tropical Systems

Things seems to be happening in the Caribbean. Now I don't have to draw my own circles.

Possible Weather Developing

Something might be developing in the green circled area. Stay tuned.