A String Of "Poor" Weather

The last couple of days we have been stuck in a string of poor weather.  Not poor in the way it was poor last week however.  Last week we had a large disturbance propagate up from South America.  The whole region was wet and the usual trade wind inversion was nearly non-existent.  This allowed the convection to go to very high levels.  The weather was therefore wet, completely overcast, and humid; not the typical situation we were hoping to sample.  We have the exact opposite problem now.  The trade winds are nearly non-existent which allows for thermal heating and convection over the islands.  Instead of an orographically driven system we have a thermally driven one.  The atmosphere is much drier, and while clouds over the island are common, there are very few over the ocean upstream of Dominica.  It is more comfortable in that the skies are clear and the air isn't as sticky, but it isn't good for DOMEX.

We are always very conscious of the time passing.  We have a certain number of flight hours to be used from April 4nd to May 8th and if they are not used, they go wasted.  Therefore, while we'd like to only fly on good days, we simply have to keep flying on these poor weather days to keep from falling impossibly far behind.  Ron and Dan noticed yesterday while flying that the convection was mostly thermally driven so mid-flight they switched the flight tracks to just run racetracks around the mountains of Dominica.  They sampled a lot of non-precipitating clouds on tracks 3 and 4 which should give us a lot of good data.

View of Dominica out the front of the aircraft.

A clear LCL seen over Dominica.

The photos above are Dan's from the flight yesterday on the 18th of April.  They contrast strongly with my photos in flight from the 14th which were included on my last post.  Notice that there are no clouds over the ocean; they are only over the island.  Today will likely look similar to yesterday.  Setting into the project we wanted to have a good number of "regular" cases and perhaps a few anomalous ones.  Instead we seem to be getting plenty of anomalous cases: wet, dry and weak wind, but hardly any "regular" ones.  We have some hope that later this week and into the weekend might be better.  The model forecasts show the wind speed picking up and turning more easterly, along with a bit more moisture.  Cross your fingers for us!