Same general theme, with a slight shift south along the southern edges and a more pronounced southern shift towards the upper part of the map. Risks are generally to the higher side on the southern fringe areas if the models are to be believed (especially if the overnight front-end thump is fairly wet).
The DC-Baltimore-Philly areas are expected to miss out on the more significant accumulations yet again as bothersome low-level temperatures above freezing and March climo. rear their ugly heads.
One of the saving graces with this event is the onset of snow will be overnight, though this did not really help the I-95 corridor and points east during the last event back in the first week of March. Surface temperatures will generally be above freezing in the lower elevations, so these areas will n
There were some detail changes due to adjustments in the storm track, which mostly affected central/northern PA, southern VA and the Delmarva Peninsula. Higher confidence in the higher snow totals brought some upscale changes to northern VA.
It's still a low confidence forecast overall, with both upside and downside risks across most of the impacted region.
So here we are with another complicated setup and poor model agreement leading to a low confidence forecast. The good news is it looks like DC is finally going to get a decent storm! It only took until March...
Anyway, right now it looks like the biggest risks are along the coast and in PA and southern VA. I'll save some of the more intricate details for the final forecast, but there is going to be some serious issues with the rain/snow line in the lower-total areas to the south, with precip. s
Boundary temperatures and snowfall rates will be the two main things to watch tomorrow as a nice looking vort. max passes over the region. Precipitation will start off as rain for most/all of the region tomorrow, with the back end of the system changing over to a heavy, wet snow. The strong vort. max will help dynamically cool the air as decent rates form up along the back part of the storm, but with the boundary layer temperatures remaining at or above freezing, it will be hard to get a lot of
Much more aggressive with the totals this time around, but there is still more upside risk than downside to the forecast.
I went with a rough 50/50 blend of the GFS and Euro, with some personal touches here and there. NAM's still out to lunch with it's QPF and snow totals, so I didn't even bother with it. There's going to be some winners and losers in the low-end/mix areas as the details work themselves out. The bulk of the snow across northern MD, southern PA and southern NJ will be during t
Just going to start off by saying that forecast confidence is lower than normal. Miller B type storm will form up late tomorrow into Friday and will initially cause mixing/temp issues across the more southern areas. As the coastal intensifies, banding on the back edge of the system could bring locally higher totals from central PA to NJ, NY and maybe even down into northeast MD and northern DE. There's plenty of risk in either direction, especially across central PA into NJ and NYC/LI.
Somewhat higher confidence in the QPF totals brought about an expansion of the 2-4" area. The GFS/NAM continue to suggest a snow hole in the northern VA and DC region, which remains a slight risk to the low side. Overall, I think risks are more to the high side, with localized 2-4" totals possible within the 1-2" contour. Likewise, the 2-4" contour could see localized totals of 4-8" (which is more so for the Appalachians than anywhere else).
Certainly a new breed of winter storm for this winter as we now have plenty of cold air in place, but moisture will be lacking in most areas. The good news is most of the Mid-Atlantic will see high snow ratios around 15-20:1, giving the event more bang for the buck.
Risks are more to the low side at the moment, with the current forecast leaning more towards the wetter European solutions. The NAM and GFS have been fairly insistent on a DC snow hole where accumulations are less than an inch. Whil
A quick update before I head into work... shifted the forecast further south overall and tightened up the contouring in areas that have slightly higher confidence than the initial forecast.
This results in a virtual no-show north of DC aside from some flakes in the air to a dusting. Southern VA into northern NC will get rocked as the vort. max pushes through. There is a risk of this shifting even further south according to some of the hi-res models.
Here comes the first notable snow event for the southern Mid-Atlantic this winter! A powerful upper-level vort. max will push through the region tomorrow, bringing strong dynamics with it that will help create a period of moderate to heavy snowfall. The snow will start in the morning hours in the higher elevations and will work east through the afternoon and evening. The I-95 corridor will probably start off as rain in the morning. Some sleet could accompany the transition in the late morning an
Very tough call on the southern edges of the contours as sleet and freezing rain make an appearance as far south as northern MD (not including the mountains).
Some locally higher totals of 4-8" are possible, and I put a 4-8" contour area in the spot where I think that is most likely to occur. Ratios should be above 10:1 at least at the start of the snowfall across northern PA before the warmer mid-level air tries to nose in.
I did end up bringing the contours further south from DC eastward. Not really anything to add to yesterday's discussion.
Good luck with the snow, everyone. I'm leaving to go up north now where there's 18 inches of snow on the ground.
Another quick-turnaround forecast as the next system looks to bring widespread 1-4" totals to the Mid-Atlantic, with higher totals in the central Appalachians. Marginal boundary layer temperatures and initial surface winds out of the southeast makes finding that 1" boundary a challenge yet again. Luckily, the upper-level temperatures are cooperating more this time around, so if your surface temperature is at or below freezing you'll almost certainly be getting some accumulation. Mixing areas wil
Forecast confidence is low as most of the snow falls at the front end of the system before many areas switch over to mixed precipitation and/or rain. Very small changes in temperature at various levels of the atmosphere could lead to significantly different snowfall totals, especially east of the mountains. The northwestern parts of the forecast region could/should stay all snow throughout the event, which roughly matches up with the 8-12+ inch area along and west of the mountains.
No major changes to the forecast, though I did decide to go a bit more aggressive with the totals in some areas. The most notable changes were in northern PA and southwestern NY, with an 8-12" contour added as lake-effect off of Lake Erie helps drive up totals. The back edge of the main area of precipitation is expected to change over to snow, but how much of that actually accumulates ahead of the later snow is uncertain.
Localized totals of >12" are possible within the 8-12" contours.
Since my forecast maps cover parts or all of several different sub-forums in the eastern US, I've decided to just post my snowfall forecasts on this blog to get more exposure without having to spam all of the different sub-forums with my forecast.
For those of you who don't know, my main focus with snow forecasting is centered around the Mid-Atlantic. The geographical location does not regularly change from storm to storm, and neither do my snowfall contours. You can interpolate snowfall totals