Good Saturday morning everyone!
It is nice to be able to exhale a little bit after an active week, though the weather itself stays active in terms of national headlines. Yet another strong coastal Nor'easter gets its act together and heads toward New England. As we have discussed on this blog before, it owes much of its beginnings to the parent system that came through yesterday and is now in the Great Lakes region:
|HPC - Surface Map - Saturday|
Notice the trailing front that exists in our local area courtesy of the low pressure area in the Great Lakes. It turns out that despite the spawning of the coastal low, both systems still maintain themselves a little bit, at least initially, stalling the full transition to the coastal storm. Checking out the wind streamlines on the NAM model products bears this out in more detail:
|NAM - Wind Field - Saturday Morning||NAM - Wind Field - Saturday Night|
So, we have an area of "convergence" at our front that works through the tri-state during the first part of Saturday (and of course plenty of convergence at the center of low pressure off the Delmarva Peninsula). We also have an area of "divergence" along the Appalachian Mountains-- an indication that the coastal low just doesn't have enough strength at the outset to entrain airflow from our side of the slopes. This has interesting ramifications, as folks along I-79 and Corridor-G can again enjoy a mild surge of temperatures today toward 50, but areas on the eastern facing sides of the mountains may well get stuck in the 30s for a while; the first group getting warm air advection from the south, and the second getting cold air advection from the northeast. By the time the coastal storm fully takes over on its ride toward New England, we'll be too far away to receive any cold air return around the west side of the low, and instead already be in the wind regime of calmer westerlies. This solution on the models has a lot to say about whether we're going to see rainfall today.
|NAM - Precipitation - Saturday Morning||NAM - Precipitation - Saturday Evening|
Allowing for the often-verified reality that the mountains will catch a piece of every storm that comes through, it would appear that just they are in line for possible showers, while the rest of us will see a cloud deck occasionally broken by peeks of sunshine. (Note: however, in any convergence zone there exists at least a slight opportunity for showers/sprinkles, even though the models aren't putting this forward-- if you do get a brief period of drizzle, you'll know where it's coming from) Given that high pressure returns for Sunday, the weekend picture really doesn't look all that bad. In fact, get out and make the most of it, because next week we've got another sloppy system on the way.
The latest GFS runs have taken the storm into the area on a similar tack as this past storm, but the results beyond that are interesting to say the least (and perhaps a little on the questionable side):
|GFS - Tuesday Afternoon||GFS - Wednesday Evening|
The parent low never really quite relinquishes control this time, and ultimately stalls out over Lake Huron (often an indicator for some pretty big lake-effect snows for upstate New York). There will be a few wind-up low pressure systems that rotate off the base of this parent low, but they don't really rise to the level of a good storm just yet (there's indication that the end of next week will get us a strong enough coastal low to push the whole mess off-shore).
The first picture inidcates an environment quite similar to what we went through yesterday morning, but perhaps just warm enough to keep us in the rain category, rather than icing. Notice the 'log-splitting' effect of the mountains when high pressure blocks advancement to the north. Precipitation appears to split to our south and split to the northwest, leaving much less in the middle.
The next image for Wednesday night shows the stalling low over Lake Huron having a wide circulation channeling a good amount of lake-enhanced moisture across much of the Ohio Valley. Even though this 'could' mean snow showers, I actually have in mind that this may suffer from a lack of good enough cloud development such that we'll be battling drizzle and freezing drizzle instead of developed snowflake growth. Whichever it ends up being, we may be stuck in that same pattern for a few days in a row. It's a good thing that models are quite change-able between now and then :-)
|Regional Radar/Satellite with Warnings Tracking||
From the Storm Prediction Center (below): Click For a Larger Image
|Activity Overview||Storm Outlook||Watches||Potential Watches||Storm Reports|
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!