Raleigh Weather Discussion
We will see a cool but dry next couple of days as cold polar air builds in and this cold, dry air will set the stage for some minor precipitation-type issues Friday morning before a steadier rain sets up Friday night into Saturday morning.
Partial thickness and model forecast soundings suggest the low level air mass will be quite dry Friday morning and as we see some isentropic upglide precipitation will likely break out in the wee hours Friday morning and overspread from SW to NE. With the dry air at the surface we could see temperatures fall to near freezing especially along the I-40 corridor north. This could lead to a period of sleet and possibly freezing rain late Thursday night and Friday morning. As of now outside the northern foothills area potentially near the escarpment, I do not expect major issues. But the Va/NC border counties could see a light glaze of ice on some elevated surfaces and perhaps a few hours of sleet. In the Triangle, there could be a period of sleet/freezing rain but I expect very little issues.
Everyone will transition to rain by late morning and rain that falls on Friday will likely be light. The rain will pick up in intensity Friday night into Saturday morning with a good period of moderate to at times heavy rain, ending by mid-day Saturday.
The next storm system moves in late Monday and into early Tuesday. Right now this looks to be rain. It then looks mild mid next week before the next system moves in by Thursday.
The 00z ECMWF shows a potential rain to snow scenario with this system while the 6z GFS is rain. So this could be one to watch, but my lean is since it appears cold air will not be entrenched before the system is forecast to form, it will be difficult for this to be a significant winter event. There is some potential with the pattern setup though for the first several days of March.
National Extended Weather Discussion
The combination of a –NAO/-AO/+PNA looks to support a cold pattern as we head into early March. The EPO looks to remain + though so the cold pattern may not run wild but for the South/Southeast/Ohio Valley it certainly looks colder than normal.
There seems to be good agreement in the major ensemble suites to support this forecast. So although wintry weather in the Southeast in March has been rare in the last 25-30 years, it looks like we may see a pattern cold enough to support chances if we can get well timed impulses.
Again this cold pattern seems to run in the face of what the MJO phase we are going through and forecast to go through would suggest. I will say this though, although the MJO wave is forecast to move through the warmer phases 4-6, it is forecast to lose amplitude and thus probably influence on the pattern, so that could be part of the reason we do not see a sustained warm pattern develop.
I am still closely monitoring the first few days of March for a potential winter storm, so stay tuned.