December 2023 Observations and Discussion

Some light flurries here now at work in Allendale

amugs wrote:This is going to be an interesting one, LI in the bul's eye of the winds

wow. Is this like a svr tstorm type wind thing or longer duration? Yonkers 60 mph thats def go cause some outages and likes from li and east ct ri and ma. Meanwhile snow flurries at 37.

Little over an inch here in Yatesville Pa. I didn't get an exact measurement.

73 de AC3GI

mikeypizano wrote:Little over an inch here in Yatesville Pa. I didn't get an exact measurement.

73 de AC3GI

Nice he has come out of hibernation LOL!!

Flurries here in Allendale again.

jmanley32 wrote:

amugs wrote:This is going to be an interesting one, LI in the bul's eye of the winds

wow. Is this like a svr tstorm type wind thing or longer duration? Yonkers 60 mph thats def go cause some outages and likes from li and east ct ri and ma. Meanwhile snow flurries at 37.

Upton has a pretty decent take on this.  

Global 00Z guidance is mostly in agreement with the evolution of a
frontal system late Sunday into Monday with only minor timing
differences. A longwave trough will develop in Colorado and New
Mexico moving into the Great Plains allowing a Colorado Low to
develop in north Texas/Oklahoma Saturday morning. A shortwave
develops within the longwave trough in the Upper Midwest that
accelerates the low northeast into the Great Lakes and subsequently
into Canada Saturday night. The longwave then becomes much more
amplified as it moves into the Mississippi and Ohio River Valleys.
It develops another low in the Tennessee Valley on Sunday morning
along a strong cold front extending from the first low that has now
moved into Quebec. Unlike previous guidance, as the trough moves
towards us and passes Sunday into Monday, it is no longer expected
to become negatively tilted. The only 00Z guidance with this
solution is the UKMET. This means this system may not be as potent
as previously forecasted, but it still will be and may pass by a
little quicker once it has arrived. Sunday night into early Monday
morning the cold front is expected to pass with the low overhead,
which will then further develop as it moves into New England on
Monday.

A strong low-level jet is expected to develop ahead of the front,
leading to strong warm air advection at the surface. Highs will
reach the low-60s on Sunday, preceding the cold front. The low-level
jet will reach its peak over the eastern half of the CWA where winds
are expected to be the strongest around midnight at about 60-70 kts
(model guidance varies between 50 and 80 kts), with south winds
first beginning to increase across the area Sunday afternoon. Wind
gusts are currently projected to peak 40-45 mph for the southern
half of the CWA with northern interior areas reaching peak
gusts around 35-40 mph. After the frontal passage late Sunday
night into early MOnday morning, breezy WNW winds will take over
sustained at 15-20 mph on Monday before weakening Monday night
as the pressure gradient weakens from the departing low.

Saw a heavier snow shower earlier. Nice to boost the holiday mood a bit.

For Monday morning have to watch if the coastal can start wrapping cold air in time for any snow. Any slow down of that coastal could have a large effect on those NW I-95 especially toward Mike P's area on I-81. The 500mb trough going negative will enhance precipitation as will mid-level closed off circulation but as of yet not sold on much outside of I-81 where several inches could fall.

heehaw453 wrote:For Monday morning have to watch if the coastal can start wrapping cold air in time for any snow. Any slow down of that coastal could have a large effect on those NW I-95 especially toward Mike P's area on I-81. The 500mb trough going negative will enhance precipitation as will mid-level closed off circulation but as of yet not sold on much outside of I-81 where several inches could fall.

Bahh, you beat me to it!! Hahaha the GFS/NAM and to an extent, the RGEM definitely have an intriguing setup, with a fairly infrequent anafrontal snow event. You hit the nail on the head with your post, and I’d add that there will be significant frontogenesis and jet support as well, which will all work constructively to produce significant forcing for ascent and precipitation. As you said, though, do the mid-levels tilt negatively in time to allow the cold advection to outpace the precipitation shield? That’s the key, and what we need to figure out. It definitely requires a further look. If it was JUST the GFS, I wouldn’t care lol but to have the NAM and RGEM, now it has my interest.

I might try to look tonight after work if I have time.

Nino basin wide, but looks to have cooled a bit as Mugs pointed out.

heehaw453 wrote:Nino basin wide, but looks to have cooled a bit as Mugs pointed out.

Here's looking at it from a diff angle.

GEFS are saying check to NAM, RGEM now ticking that cold air in a tad faster. Interersting especially NW now.

Meanwhile, the EURO says “Bah humbug, Scrooge you!” lol gotta love it

rb924119 wrote:Meanwhile, the EURO says “Bah humbug, Scrooge you!” lol gotta love it

So if it is going to head towards negatively tilted scott had posted that NWS had lowered idea of such intense winds so are we looking at possibly above 50mph again. even as high as the GFS which for east of NYC is nuts and would be damaging with a lot of power outages IF it were to occur. That snow is so close to me I would love to see some flakes even if at the end.

Didn't that horrible snowstorm that halted traffic in Nov. years ago do something similar? It was exopected to be rain then some snow then 6+ at the last minute?

18z (happy hour) NAM asked us to hold its beer lol

Yeah Rb. The NAM is tilting the trough pretty quickly. Really allows the colder air to move in. Have to see if it's on to something...

It in a decent year it finds ways to snow and that starts in December IMO. We'll see.

heehaw453 wrote:Yeah Rb. The NAM is tilting the trough pretty quickly. Really allows the colder air to move in. Have to see if it's on to something...

IF true, it’s my experience that these situations tend to over-perform. So the totals it’s printing out aren’t unrealistic at all, in my opinion. There was a similar situation back in November of 2014 (I believe) that was similar to this. I’ll have to look back through my forecast archives to see the actual date and then pull up the ESRL PSD maps, but I was extremely bullish on forecasting snow for that one, with 2-4” as my max totals. Ended up with 7 or 8. The problem is these setups are SO fickle, which is why they don't usually materialize.To your point, though, 2014-2015 was a good season - possible parallel? lol

Edit: November 19th, 2016. I had 3-5” maxes. I’ll look more into this tonight.

rb924119 wrote:Edit: November 19th, 2016. I had 3-5” maxes. I’ll look more into this tonight.

Ray I just mentioned that storm above lol, guess you missed it. That was the one that snarled traffic for 12 hours. My wife and daughter did not get home until 1am after leaving from 6 miles away at 5pm....

Flood watches up for the majorita of area and high wind watches up for LI and cape code 60mph-65, wow. Guessing my area will likely see around 45-50mph as NWS shows but it this thing ramps up more than was showing it could be worse. Hoping we can get a WWA for the back side or heck is there anyway it doesnt rain at all even to the coast hahaha

jmanley32 wrote:

rb924119 wrote:Edit: November 19th, 2016. I had 3-5” maxes. I’ll look more into this tonight.

Ray I just mentioned that storm above lol, guess you missed it. That was the one that snarled traffic for 12 hours. My wife and daughter did not get home until 1am after leaving from 6 miles away at 5pm....

No, Jman, that was 2018 I believe you’re thinking of haha totally different setup. That had an unusually cold preceding airmass that the storm was running into, and models overplayed the strength of the warm advection in the beginning, and its ability to warm the column above freezing. This upcoming storm is one where the cold air is going to be chasing the precipitation. I can expand on your other comments later after I get out of work, though, if Scott, heehaw, or one of our other residents doesn’t beat me to it haha

Lol. the 18Z GFS barely gives Binghamton NY 1" for Sunday night/Monday morning. I'll take the over on that.

Nws upton increased rain totals to 2 plus for entire area and significantly increased peak wind gusts for example my arwa spot went from 40 mph to 52 mph. Def seems like they are thinking this will be stringer again. Even mentions the chance for snow nw.

I had a moment to take a look at the impending storm later this weekend, and man this is quite the trough! The energy coming into the CONUS through the PAC NW is very strong. In fact a little too strong. We’re going to see temps ahead of the storm climb into the 60s. That’s because there are actually 2 Pacific upper level short waves semi-close off over the Midwest which causes heights along the east coast to rise



Late Sunday afternoon into evening, we see another upper level short wave drop into the CONUS from Canada. This one catches my eye, because it attempts to phase into the trough which causes the surface low to strengthen and pull down cold air. I’m not thinking the coast will see accumulating snow out of this - mostly because I think the phase doesn’t happen on time (little blocking and collapsing PNA ridge) - but can’t rule it out for interior sections even some close to home N&W of NYC. Right now higher elevations in PA and NY are game for accumulations. Curious to see what happens with models tonight into tomorrow.