It's been an interesting few days weather wise throughout the Tri-State region, as a storm system passed to our west and northwest last night. It's interesting to note that our area was warm sectored in an almost summer-like set up, which allowed for warm air advection and the development of elevated CAPE and instability. Thunderstorms developed well to our southwest and shifted northeast through the warm sector, while elevated cape allowed for continued thunderstorms throughout the night. The front has since passed and the airmass has cleared out across the region, allowing for a beautiful fall day to prevail this Friday. As far as sensible weather over the next few days, things will be clear through at least Sunday afternoon, when a piece of southern stream energy will begin to turn negatively tilted and approach the east coast. It's reasonable to assume a low pressure area will form off the North Carolina and eventually Mid-Atlantic coast in response to the PVA/shortwave. However, the deepening of this storm is expected to be tempered a bit by the presence of the confluence and high pressure to the north and the relatively weak nature of the shortwave by the time it turns up the east coast. Still, with the aid of the offshore baroclinic zone, the presence of the aforementioned, although weak, surface low pressure should be sufficient to develop precipitation along the eastern seaboard if the coastal low pressure can infact form well enough to the north and west. We've included todays 12z GFS Operational run to the right, valid Monday, showing the mentioned low pressure and associated precipitation, as well as 500mb vorticity and 700mb relative humidity.

The OP GFS has consistently been well northwest of all its ensemble members, but it's worth noting that the GEFS ensemble members and ensemble means are notorious for being well too far southeast with coastal low pressures in this range. That said, we have enough confidence in precipitation Monday that we've included it in the text and graphical forecasts. It will be interesting to watch model performance with this event, and throughout the rest of the autumn as we head down the road towards winter. Another storm threat seems to be revealing itself towards the end of next week as a large piece of northern stream energy dives southeast towards the MS Valley. Forecast guidance still has a wide solution envelope with this one, but the potential is there for coastal development and a high-precipitation type event if the phase can in fact occur/ i.e the more wrapped up solution pulling the low closer to the coast. We will have to keep an eye on this one over the next several days as well.

Speaking of down the road towards winter, we've made several posts regarding the potential upcoming pattern change. ECMWF and GFS Ensembles continue to signal the retrograde of the Gulf of Alaska vortex towards a more favorable position in the Aleutians, as well as the development of a +PNA Ridge along the west coast. However, in order to get more than brief cold (a more sustained cold pattern) throughout the Eastern US, we will need the aid of a more favorable NAO state as well as a -EPO Ridge. Some medium and long range ensembles have been very favorable, developing a cross polar flow and extreme negative anomalies across the Northeast. Others, however, keep the pattern progressive and (aside from the initial cold shot mid-next week), keep anomalies near normal as the pattern re-loads across the Northern Hemisphere. We've included an example of the spread to the left of this text, you can see the highly favorable members as well as the more-neutral setup kind of members. The NAO/EPO state will dictate how this plays out.

Finally, figured this was a good time to make an announcement regarding some house keeping and upgrades around the website. There have been and will continue to be several changes around the website itself, especially the forecast operations and details. The first will be the inclusion of two graphic images to go along with our forecasts. We've been playing around with several graphics, but the final decision involves only the five day forecast and the current weather tab. The general feeling amongst the staff is that having several graphics is over-done, and that the point can be made with a five day and current weather tab. We will occasionally include short term (two/three day) graphics within the forecasts when necessary. Additionally, you will soon (when winter approaches) begin to see snowfall and precipitation forecasts in the "Graphic Forecasts" page, we didn't want you to think that we forgot about it. The final addition will be "Snowfall Forecast Services" which will be snowfall forecasts and details (including alerts, specific area forecasts, timing details, precipitation intensity details, weekly digest, monthly summaries, and post event summaries) available for personal and business use for a subscription price. Additional information regarding this service will be released over the next few weeks, although if you would like immediate details or information you can email us using this link. We will have many more posts and improvements over the next few weeks, so stick around.