Too early to hang one’s hat on the this, but while I’m at it, I thought I’d share the latest GEFS snow forecast for WEDNESDAY into THURSDAY—

 

from Friday night…

So, I had closed the book on the new pre-release GFS model v 16 prediction of some light non-accumulating snow on Monday morning. (See this morning’s post.)

However the new NAM model data has become available this evening and it has quite a surprise. Hard to believe, but it’s showing dynamic cooling just northwest of Philadelphia and some accumulating snow!

Here’s the latest NAM model snow forecast—

The NAM tends to over-forecast precipitation this many hours in advance, but the forecast for Monday remains interesting, especially after 60º high temp forecasts for Sunday! Stay tuned.

Tonight’s GFS also shows significant snow in the Wednesday – Thursday timeframe

From earlier today…

On Sunday evening into Monday, most models have low pressure developing in the southeastern US and moving up, just missing the Philadelphia area.

Interestingly, the new soon-to-be-released GFS model version 16, (still in test mode, expected to become operational In January-February 2021) has been consistently showing a different track than other models, a track that would brush our area with light snow early Monday morning.  Most areas will NOT receive any accumulation (too warm at the surface), or a coating at most, shown in the second graphic.

This model currently is an outlier. Most other models have to moving off to our south, missing us.

The latest NAM model suggests it might have moved into the new GFS model camp.

It’s interesting that the major US model scheduled to replace the existing GFS in a month or so consistently has had such a different forecast. Stay tuned. I’ll keep an eye on it.

(BTW, the long range model forecast suggests another ‘interesting’ weather event next Wednesday or Thursday.)

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from Monday …

We have a chance of seeing the first snowflakes of this season early Wednesday morning. A weak upper air disturbance (clipper system) will move through the Philadephia area between 6 AM and 9 AM Wednesday morning.

Snow flurries are likely but most areas will either get no accumulation, or a light coating at most. Current water equivalents are very low, about 0.03 inches.

If this sort of non-event were to occur later in the season, it might not even merit a blog posting, but being the first flakes, I thought I’d get into gear.

There are some differences in model timing with tonight’s NAM and NAM-NEST having the this occur later in the morning. Stay tuned.