FEB 17th-18th Snow? Sleet? Rain?

Im pretty sure this is credible enough now to have its own thread.  The euro came in pretty much with the best case scenario at 500mb.  Not surprisingly the surface maps agree.

Do not take this as a forecast because I still think things could change. Euro surface maps and snow fall with no ratios for the Jman and others who probably wanted to see it as well.

I’m not getting suckered in. Still don’t like the looks of HP and WAR. My next post on this event (or lack thereof) won’t be till Friday evening

Given that the high pressure system driving the low would be to our east, the GFS's rainy solution for the coast seems to be more logical at this time.  Also keep in mind that the theme for this winter has been the last minute NW trend.  If that is the case this time around, I would expect the rain/snow line to go that way.

GFS is a swing and a miss OTS. Can't make this stuff up. I'm not buying that solution.

aiannone wrote:0z NAM lookin good

Notice the rain/snow line is now right along the coast as opposed to well off the coast like the 18Z NAM was showing. This looks like a red flag and the start of a trend where the coast sees rain and the snow is north and west.

Dunnzoo wrote:

Math23x7 wrote:

aiannone wrote:0z NAM lookin good

Notice the rain/snow line is now right along the coast as opposed to well off the coast like the 18Z NAM was showing.  This looks like a red flag and the start of a trend where the coast sees rain and the snow is north and west.

Well, it IS our turn Mikey!

Perhaps so far north and west so that only Doc/CP get snow

Barely any storm at all on the GFS. Still there on CMC, German, and NAM. NAM and German look a bit north and would entertain boundary later issues along the coastal plane, while the GFS is way suppressed. Could be it’s progressive bias.

This has been on the models fairly consistenly and progged pretty much to be in the same spot for a while now. I am growing more confident we will see a snow event here. The GFS had it but adjusted south but I think it's the mid range progressive bias kicking in there.

Temps will be marginal, highest snow potential NW of 95 and 287. Rain more likely on immediate coast. (By no means locked in, but stating the precip profile I would expect to see if it materializes.) It is a really transient shot of mild cold (for this time of year anyway) and temps will begin to rise above freezing again pretty much as precip ends. Addtl. flooding concern with how saturated the ground is right now, and the addtl. rain/ quick snowmelt won't make things any better.

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A progressive flow across the Lower 48, largely dominated by
the southern branch of the polar jet, will undergo
amplification by early next week. A upper trough digs south
across the intermountain west, while a high amplitude ridge
builds off the southeast coast. The latter of which may bring
record warmth to the area next week. First though, a fast moving
winter storm will follow on the heels of a fleeting shot of
cold air Friday night into Saturday.

The GFS is the southernmost operational member in taking low
pressure to the south and east of the area Saturday night into
Sunday morning. It is also weaker than the ECMWF and NAM. This
is likely due to its poor handling of cold air damming east of
the Appalachians as high pressure quickly races to the east on
Saturday. Granted, the location of the high is not ideal for
damming, nor for a moderate to heavy snow event. However, the
fast development of the low along the Mid Atlantic coast
Saturday afternoon, which quickly passes to the southeast, may
only result in a short period of weak onshore flow. A SE flow
along the coast is typically a snow to rain event, but in this
case a rain/snow mix at the onset may go to all snow fairly
quickly as winds shift quickly to the NE. In addition, a deep-
layered W-SW flow does not look to erode the cold air aloft,
with the main question thus being the boundary layer
temperature.

With about quarter to half inch of liquid across the area,
there is the potential for advisory level snows (2 to 4 inches).
Should the ECMWF`s wetter solution come to fruition, possibly a
low end warning event (around 6 inches). The best chance for
this to occur would be along or just inland from the coast due
to the higher QPF forecast, provided the event can be mainly in
the form of snow. Temperatures are forecast to be in the 20s
inland and in the lower 30s along the coast.

Thereafter, a significant warmup ensues through the middle of
next with a deep-layered SW flow to develop as high pressure
strengthens off the eastern seaboard. Highs Tuesday and
Wednesday may get to around 60 across parts of NYC and the
interior, but it will be considerably cooler along the coast due
an onshore flow.

aiannone wrote:12z NAM rolling. Looks amped

Looks colder too.

It is going to be a close call where the rain/snow line sets up. A weaker system means colder temps and snow for most people. A stronger / northerly track system will bring rain to the coast while bringing heavy snow to the N&W. I do not like that the cold air mass on Saturday appears stale, and that there is a High Pressure exiting off the coast Saturday afternoon into evening. At this time I would expect more wet than white along the coast and a moderate snow event for those N&W.

I may put out a snow map later today

Frank_Wx wrote:It is going to be a close call where the rain/snow line sets up. A weaker system means colder temps and snow for most people. A stronger / northerly track system will bring rain to the coast while bringing heavy snow to the N&W. I do not like that the cold air mass on Saturday appears stale, and that there is a High Pressure exiting off the coast Saturday afternoon into evening. At this time I would expect more wet than white along the coast and a moderate snow event for those N&W.

I may put out a snow map later today

Frank I would argue that a stronger system but a track say off the delmarva would actually enhance snow totals along the coast. A stronger system does not necessarily mean the track will be too far north. With an exiting HP the weaker system would more likely lead to a more easterly/southeasterly wind component for longer vs a tighter system would quickly lead to the E to NE component keeping mid levels colder. With a decent jet streak placement and intensity and the H5 modeling of the subtle phasing and stronger N s/w a stronger system is where Im leaning right now.