Rich Thompson
EF3
In reference to Jeff Snyder's ealier post regarding the low-level moisture:
The big problem we have is not a modifying "continental polar" air mass, but a relatively *warm* and dry continental air mass over the Gulf basin. The sea-air temperature differences are minimal, which suggests that sensible heat fluxes will also be minimal. Why does this matter? Well, there's little to generate a deep/moist boundary layer over the ocean without the temperature difference to drive mixing. That's the big reason why there's been so little change in the moisture for the past 3-4 days at the buoys and coastal locations.
The offshore flow phase and a relatively warm air mass:
http://www.chasetolive.com/images/CRP1.gif
The onshore flow phase with a shallow marine boundary layer:
http://www.chasetolive.com/images/CRP2.gif
Until we get the old frontal zone in the Caribbean to retreat back to the NW, we'll continue to have problems with a "shallow" marine boundary layer that's susceptible to "mixing out" inland. It may seem counterintuitive, but we would be better off now if a much colder air mass had scoured the Gulf basin!
Rich T.
The big problem we have is not a modifying "continental polar" air mass, but a relatively *warm* and dry continental air mass over the Gulf basin. The sea-air temperature differences are minimal, which suggests that sensible heat fluxes will also be minimal. Why does this matter? Well, there's little to generate a deep/moist boundary layer over the ocean without the temperature difference to drive mixing. That's the big reason why there's been so little change in the moisture for the past 3-4 days at the buoys and coastal locations.
The offshore flow phase and a relatively warm air mass:
http://www.chasetolive.com/images/CRP1.gif
The onshore flow phase with a shallow marine boundary layer:
http://www.chasetolive.com/images/CRP2.gif
Until we get the old frontal zone in the Caribbean to retreat back to the NW, we'll continue to have problems with a "shallow" marine boundary layer that's susceptible to "mixing out" inland. It may seem counterintuitive, but we would be better off now if a much colder air mass had scoured the Gulf basin!
Rich T.