Weather Briefing 20050128

Will focus on the selected forecast issues of a possible storm early next week, clouds in the next few days (mostly Saturday), and the stratosphere. For a good short term (through weekend) forecast, go to http://www.erh.noaa.gov/gyx/forecasts.html and click on Portsmouth. The short answer is that we have flyable conditions at least through Monday

Models still differ on the likelihood of a storm next week. It is a complex forecast problem, with a split upper level flow situation developing across the continent. This includes a west northwesterly flow from Canada, and a southwesterly flow stretching from a deep tilted trough centered over California and Arizona towards the middle Atlantic. Some of the models have been calling for a strong low developing off of the New England coast. That appears less likely at this stage, with most of the action occurring south of us.

There is still no real convergence in the model solutions. However, neither the Euro nor the GFS call for any sort of strong closed low off of our coast through the middle of next week. If the GFS is to be believed in the long term, we have no significant weather and no significant thaw (meaning temps above freezing) for the next 10 days!! My own reading, and that of the experts, is that Tuesday and Wednesday are OK, with uncertainties.

For Saturday’s clouds, the forecasts are developing some consistency. We expect clear skies off the coast for some distance (see http://bocachica.arc.nasa.gov/PAVE/rh_omega/CA_peasetp_500mb_day118.pdf ). Towards the west, an encroaching trough brings high and mid level clouds. The window is short, however. Recommend doing the offshore outflow runs ending no later than the Aura overpass of 1815. The TES run from the Carolinas through Toronto does not look good. We have not only high, but middle clouds as well – in other words, more than just thin cirrus. There is significant forecast vertical velocity, and the forecast is consistent with yesterday’s run.

The stratospheric vortex, based on the ASM latest runs, promises to be in the area through next Tuesday (as far as I have information). Tuesday, a short wave rotating around the vortex pushes a lobe more deeply into Labrador, with cold temperature anomalies further west.