Weather Briefing for 20050206

Surface weather for Monday looks fine, with the high lingering over us for another day. We will be on the west side of the high, so winds will turn from the southwest at less than 10 knots. Through Tuesday and Wednesday the high will move southeastward. This is accompanied by the movement of cold air into the Midwest and the shifting of the northern jet stream (that has been passing over Canada the last week) southward to be just northwest of us. Low pressure systems propgating along this jet stream will give us 30% snow chances by Wednesday.

The major forecast problem for today is the question of clouds over the ocean for

Tomorrow. The total cloud forecast indicates little change from the most recent forecasts ( http://bocachica.arc.nasa.gov/PAVE//rh_omega/CA_peasetp_500mb_day118.pdf ). Essentially the clear spot off the south coast of Newfoundland has disappeared. This is mostly low cloud and boundary layer cloud. The one major change from yesterday’s forecast is that there is very little upward vertical velocity support for these clouds. They are mostly residual moisture from previous systems either spinning around the low to the south or moving northeastward along the edge of the high. In fact, vertical velocity is slightly downward at most levels. Thus, I believe that there is a good chance to find some clear areas along the TES track. By good chance, I mean about 50%, At this point it may be worth considering looking at the clear spot off the North Carolina coast. Notably, today’s satellite image http://bocachica.arc.nasa.gov/PAVE/goes12/png/ch4/last/lastch4.png shows clear air everywhere south of Nova Scotia and north of Cape Hatteras. The air is dry and not that cold, which suggests very few puffies, even outside of the warning aireas near the coast. A TES track passes through it.

In the stratosphere, new forecasts are pretty much in line with yesterday’s, and that includes Steve Eckerman’s EC forecasts. Cold temperatures below 196K (at 450K according to NMC) should be reachable along our projected current flight track. http://bocachica.arc.nasa.gov/PAVE//rh_omega/TH_peasetp_450K_day118.pdf .

Looking at tropopause heights and cloud heights for tomorrow, though, we are facing substantial high clouds as we pass through a region of elevated tropopauses from central Newfoundland northwestward. This should be less of a problem along the HIRDLS track on the way back (because we will be higher and the tropopause lower). I should note that these high tropopauses are what is giving us the minihole reported by Steve Eckerman).