Raleigh Weather Discussion
It will be another cold day today as a strong cold front moves through the area and temperatures more or less hold in the mid 30s during the day. There is a chance of a stray flurry today as well although 95% of us will not see one and even if one does occur, there will be no accumulation.
The main weather story will be the light precipitation event we have coming up tomorrow afternoon and evening. For a more comprehensive discussion of the event, please check the examiner site for an article on the storm coming up after the 12z GFS comes in. For the Raleigh area, it looks like this will be a light event as model forecast precipitation amounts have decreased overnight. Most data is in the 0.05 to 0.2 inch liquid equivalent QPF range. It also appears the trend is that the mid-levels are going to warm enough to make most of this fall in the form of sleet or freezing rain, although surface temperatures will likely edge above freezing during the day tomorrow 34-36, they will likely quickly fall into the 28-31 range as the precipitation moves in tomorrow afternoon. If the precipitation falls mostly in the form of sleet, there will be some problems as the sleet will accumulate, but bigger problems would exist if all the precipitation were to fall in the form of freezing rain/drizzle. With even a 0.1 to 0.2 inch of qpf, if this is all freezing rain, there will be ice accrual and likely some issues associated with that. My thinking is that between 1-4pm, the precipitation will begin in the Triangle as snow/sleet and quickly transition to freezing rain and sleet ending as freezing drizzle late in the evening. The period between 3-7pm is likely the time precipitation will be falling the hardest and when the primary ice accrual will occur. Even with these light amounts, there will likely be at the very least slick spots around on the roads and bridges tomorrow evening and night, so keep that in mind.
The precip should be over by early Saturday and the weekend looks dry and cold with highs in the low 40s and lows in the low to mid 20s. A major warm-up is in store for next week particularly for Tuesday and Wednesday, as temps could threaten 70 or both of those days depending on the timing of a cold front and the associated rain with it. Right now, the ECMWF is favored showing a passage of the front later Wednesday with a cool down late next week.
National Extended Weather/Discussion
As it has looked all week, the ensemble modeling this morning favors a colder looking pattern into the first 10 days of February. It is interesting though that the teleconnection indices seem to favor a weakly positive NAO, weakly negative EPO, a PNA that will turn positive late in the 6-10 day period, and neutralish values for the AO and WPO. The one thing that seems to be bullish for cold is that the MJO phase remains stalled in the colder phase7 and is expected to only move into phase 8 and perhaps phase 1 over the next 2 weeks, which are typically colder phase for the east.
Right now, I favor a colder pattern through the first half of February, with increasing possibilities of a warmer turn as February progresses, but we shall see. In the meantime we are certainly in the midst of, with the exception of the 3 day or so warm-up next week, in the most sustained cold period of the winter for the east.
The ensembles are showing pacific jet energy crashing into California early in the 11-15 day period, which when combined with the expected colder patter across the US, could lead to some big storm possibilities as we progress into the 2/3-2/8 time frame.