Raleigh Weather Discussion
An area of rain moving through the southern piedmont and Sandhills this morning will not make much progress north. So although the radar looks threatening I think the Triangle will only see some scattered light rain showers today. However, it will stay cool with temperatures likely not rising out of the 40s.
Clouds will stay in the forecast through the next couple of days with below normal temperatures as well. There is still the chance of a coastal storm to form off the Carolina coast later Saturday and Sunday. The Euro still shows some rain on Sunday in the area, but the GFS is dry. Some other high resolution models I have access to are more aggressive over the weekend with the rain, so for now I will leave the chance of rain in the 40-50% range and monitor the models. Obviously if there is more rain around Sunday will be cooler into Monday.
It looks like the coastal storm will likely move well off shore next week and this will allow for the warm air over the Plains to make some progress into the Southeast next week. Thus I have warmed the temperatures forecast for next week some and as of now, Thanksgiving Day is looking warmer than normal with temperatures likely in the mid to upper 60s Thanksgiving Day through Saturday.
National Extended Weather Discussion
This forecast is not straight forward by any stretch. The major ensemble models continue to oscillate with how they depict the NAO and trough/ridges moving across the US. The models do all agree on a very strong positive height anomaly over NE Siberia and the Bering Sea or a strong –WPO block. The placement of this feature leads to a tap of the arctic air into western Canada a weak trough in the Gulf of Alaska and a ridge from the Southwest US into the Rockies and Plains and this teleconnects to a general weakness or trough over the Southeast US as well.
They are differing some though in how they predict the NAO to play out. The GFS Ensemble is now more of a neutral to weak positive NAO look, however the ECMWF/GGEM Ensembles remain pretty solid with a moderate to strong –NAO developing during the last days of November. All the models do develop a trough in the East to close out November, but if the NAO is not in a solid negative phase we will probably see a progressive pattern as we head into December and not a locked in cold pattern.
The ECMWF Ensemble has been verifying the best as of late so for now I will ride that but with some decreased confidence as the GFS Ensemble’s waffling on the NAO state make me nervous.
In other climate/longer range news, in recent days the EL Nino has come roaring back to life with daily region 3.4 values in the +1 to +1.5C range. This is not totally unexpected by me as I did think we would probably end up right around a weak El Nino but this may raise the stakes of a solid weak El Nino through the winter if it continues. This could lead to an increased presence of the subtropical jet stream and increased storminess across the US as we progress into the Winter.