Greg Blumberg
EF4
Wow. It's been a long time since I've posted one of these. Here are 2 thoughts I've been bouncing around regarding the uncertainty of this setup:
1.) If you take a look at a lot of current ensembles (SREF, NAEFS), you'll find incredible uncertainty in the 500 mb forecast. This is more noticeable with the more recent SREF forecasts. I've never seen 90 meter spread from the SREF two days out before. This will have impacts regarding the amount of vorticity advection we'll be getting out of this trough, which will feed back into some of the essential questions regarding positioning of the maximum lift, surface boundaries, and low pressure system(s). The NAEFS does not have nearly as large of a spread, however it still poses the same uncertainty in amplitude of the shortwave trough. I would be wary of a shift in deterministic model thinking once the shortwave trough coming onshore in the northwest US starts to deepen.
2.) I too have been increasingly skeptical about the quality of moisture that will be advected up into the Plains. I first became skeptical of this last night when I saw several of the 00 UTC soundings from the Gulf Coast and watched a water vapor satellite loop. That last cold front really killed all the moisture in the entire Gulf. I'm not entirely certain that the cP airmass will be able to modify enough in time for our shortwave trough. Taking a look at the Gulf buoys from this morning, I haven't seen much of an increase in the dewpoint values overnight, and the air temperature and water temperature differential is quite small for most buoys, which doesn't lend to a lot of upward transport of energy and moisture from the ocean into the atmosphere. Many of the numerical models (12 UTC NAM, GFS) have been very optimistic about the moisture when you look at the surface dewpoint values, but when you look at the forecast soundings, you'll find that the the moisture isn't very deep. This lends me to be concerned about the daytime heating mixing out this moisture. Will there be enough balance between the moisture advection and the mixing to keep quality moisture available for the storms? It's these boundary layer processes the model can't accurately depict that'll get ya.
1.) If you take a look at a lot of current ensembles (SREF, NAEFS), you'll find incredible uncertainty in the 500 mb forecast. This is more noticeable with the more recent SREF forecasts. I've never seen 90 meter spread from the SREF two days out before. This will have impacts regarding the amount of vorticity advection we'll be getting out of this trough, which will feed back into some of the essential questions regarding positioning of the maximum lift, surface boundaries, and low pressure system(s). The NAEFS does not have nearly as large of a spread, however it still poses the same uncertainty in amplitude of the shortwave trough. I would be wary of a shift in deterministic model thinking once the shortwave trough coming onshore in the northwest US starts to deepen.
2.) I too have been increasingly skeptical about the quality of moisture that will be advected up into the Plains. I first became skeptical of this last night when I saw several of the 00 UTC soundings from the Gulf Coast and watched a water vapor satellite loop. That last cold front really killed all the moisture in the entire Gulf. I'm not entirely certain that the cP airmass will be able to modify enough in time for our shortwave trough. Taking a look at the Gulf buoys from this morning, I haven't seen much of an increase in the dewpoint values overnight, and the air temperature and water temperature differential is quite small for most buoys, which doesn't lend to a lot of upward transport of energy and moisture from the ocean into the atmosphere. Many of the numerical models (12 UTC NAM, GFS) have been very optimistic about the moisture when you look at the surface dewpoint values, but when you look at the forecast soundings, you'll find that the the moisture isn't very deep. This lends me to be concerned about the daytime heating mixing out this moisture. Will there be enough balance between the moisture advection and the mixing to keep quality moisture available for the storms? It's these boundary layer processes the model can't accurately depict that'll get ya.
