March 2021 Observations and Discussions

Beautiful March Weather - Rain to wet Snow but maybe icy conditions Thursday night
12Z GFS



Temps - if correct they crash

Yeah looks like that Thursday rain could end as a period of snow by Friday A.M.

GFS has rain Thursday afternoon and evening changing to snow from NW to SE around midnight and continuing until about rush hour Friday morning before ending. Surface temps wouldn't hit freezing until almost dawn so not sure how much would stick. Probably depend on intensity but could see it coating the ground to maybe an inch or two in some colder spots.

Chances of any accumulation would be helped a bit by the change to snow happening in the middle of the night, since sun angle would be an issue during the daytime.

New Hope update: There's a Rita's less than a mile from my house, many more in this part of the world and around NJ. Maybe one close to you as well--here's the link to find their locations: https://www.ritasice.com/locations/

All of the models show or hint at a changeover to snow at the end of the storm Friday morning to some extent or another. The GFS is a little more bullish than the Euro/NAM on intensity north of I-195. None really show more than a coating to an inch type event. It would be more the aesthetics of waking up to snow falling in the morning Friday than the accumulation impact. The exception is the South Jersey coast and Delmarva where the models seem to imply the cold air will catch up to the heavier precip before it departs and allow for the chance for actual accumulation. NAM and GFS have 2-3" across parts of the South Jersey shore (whether that can actually stick I wonder). Euro only shows a coating type event down there. GFS actually has 3-6" in parts of the Delmarva, which would be interesting.

Severe weather threat caused me to change my plans for coming home Thursday. Southern states and the SE are going to get crushed! Supposed to take the autotrain from Florida, but no way with the high risk of tornadoes! Postponing til Friday, there are worse places I could get stuck!

Dunnzoo wrote:Severe weather threat caused me to change my plans for coming home Thursday. Southern states and the SE are going to get crushed! Supposed to take the autotrain from Florida, but no way with the high risk of tornadoes! Postponing til Friday, there are worse places I could get stuck!  

Was going to say, there are definitely worse places to have to spend an extra day!

12z GFS just stepped things up a bit for Friday A.M. Showing a general 1-2" snowfall with isolated 3-4" spots well north and west after the changeover to snow. Rain begins changing to snow by 3 or 4 a.m. as Temps crash and continues into early afternoon. Temps at the surface go below freezing by dawn so if snow is still falling it may be able to accumulate before the sun comes up (which is a factor this time of year).

Again, not saying this is a major event, just that if the GFS is right, snow could impact the AM rush hour Friday.

This has been trending colder each run by about 35 miles each time. EURO is either on crack of onto something following the GFS - about 1.5" of rain before this change over but temps crash after midnight Thursday into Friday morning - C -3" (highest elevations possible 3" max)

The NAM this morning, which is now in range to be the more reliable model, has now picked up on the cold/snowy trend. It has the changeover to snow starting by midnight and snow continuing until about 9 a.m. or so. Surface temps start to drop below freezing by 2 a.m. Under that circumstance, snow, at night, with surface freezing, I think we would see accumulation by dawn.
Verbatim 06z NAM has a swath of 2-4" of snow from Upper Bucks PA through Northwest and North Jersey into the lower-mid Hudson Valley. Just south and east of that is a coating to an inch in lower northern NJ and NYC proper.

The 0z HRRR was similar but it brought the coating to an inch of snow all the way south into South Jersey.

12z NAM back off on the "snowier" solution from its last run. I think this is one of those nowcast situations as it will be highly dependent on how fast the temps crash overnight vs how fast the precip moves out. Most of this will happen while we sleep so either you wake up to a nice little surprise tomorrow morning of some snowflakes flying and maybe a fresh coating on the ground, or you wake up to cloudy skies and cold temps with some icy patches on the wet surfaces. Gives you a mystery to look forward to.

12z HRRR

UPTON's take:

Behind the front, cold air will filter in throughout the night.
This will change any rain to a rain/snow mix, then all snow from
northwest to southeast. Sleet may briefly mix in as well before
a complete change over to snow. While a changeover to all snow
is expected, even along the coast, much of the precipitation
will be on its way out while the transition is occurring for
most places for any real accumulating snow. The best chances for
any accumulating snow is across northern Lower Hudson Valley
and inland southern Connecticut. 1 to 2 inches is possible in
these areas, while under an inch is expected elsewhere. Little
or no snow is expected for New York City and Long Island.

There is a slight chance for light snow early Friday morning for
the New York City metro area and Long Island, but again, no
accumulation is expected. Dry conditions are then forecast mid
Friday morning onward as high pressure builds in from the
northwest. Clouds will diminish, with mostly clear skies by the
afternoon.

18z NAM is off it's rocker but i would take it

The latest HRRR and NAM  Show the last impulse moving in between 2 and 8:00 a.m. and actually favors Long Island

Snow line developing in the mountains 1st then push SE

Did anyone get any snow? Had thunderstorms roll through here last night.

Agreed. I think I’ve seen my last snowflakes of the season. Onto Spring.

No new snow here at all.  Although I still have piles of it in my front yard.