CAPE

Progressive flow continues to rule. Not expecting the GFS to score a coup here given its recent issues at range, but who knows. Sometimes everything does align and time perfectly. We definitely need a HL/NA atmospheric block up in here. Maybe next year, with a Nino.

Snippet from Mount Holly AFD regarding Friday into the weekend.. A robust cold front approaching from the west is expected to pass through eastern Pennsylvania, eastern Maryland, Delaware and New Jersey around Saturday morning. The boundary will likely bring additional showers along with a sharp drop in temperatures. A drying trend and below normal temperatures are anticipated for Saturday night and Sunday. Doesn't seem like they are too concerned with the GFS idea, and to be fair it is not depicting a major snowstorm, but it is markedly colder/more wintry. Either way their thinking is some showers followed by a cold front, much like the Euro/CMC depiction.

In some species of mosquitoes the adults hibernate and survive winter, so a day or 2 in the 70s will likely bring them out.

The Euro and CMC(and their ensembles) are sticking with the warm-wet followed by cold-dry outcome for now. Check out the Euro vs the GFS for Sat afternoon. It is snowing moderately on the GFS here with falling temps verbatim, while the rain is pushing east and the cold front is about to move through on the Euro.

73 here. I see bugs.

A tad lol. GFS gets it done with fine precision- the timing, the dig, the tilt, and it leaves nothing behind. I'm confident that will work out.

12z Canadian, compared to the 12z GFS at h5..

The GFS is phasing the NS energy with the southern vorticity sooner, and leaving no energy behind, so the trough is sharp and goes neutral then slightly negative, which allows a surface low to form and and track up along the coast. The CMC and Euro don't have that clean interplay and the trough is broader and positively tilted, so any low that forms just gets shunted out. The GEFS is a little in between, but given the character/orientation of the trough and the location of the coastal low(offshore) depicted on the mean, it is leaning more progressive.

Some pretty good thunder here all of a sudden. Looks like a decent cell mostly just to the north. Getting a good downpour at the moment.

Would be nice to see the other globals to move towards the GFS idea. We shall see.

It's uncertain how much qpf this will even generate. Looks like a fairly weak wave, and the GFS keeps the precip mostly south. We know the deal this time of year- weak lift/light precip and marginal temps is a non starter.

The midweek deal looks a little underwhelming.

The Euro has temps into the 60s next Saturday, with heavy rain showers ahead of the front, then the cold comes in later in the day, while the GFS has temps falling into the 30s with a developing coastal low and rain changing to an accumulating snow. Some modest support on the GEFS. Kinda hard to buy into the GFS idea given how progressive the longwave pattern looks, and ofc its recent track history with being overly aggressive with the cold.

GFS/GEFS is back to emphasizing low pressure along the coast, in contrast to the Euro/CMC, which have a low tracking to our NW late week. I mentioned the best chance for frozen looked like it might be Saturday with some sort of coastal development, and the 6z GFS does exactly that. GEFS still hinting at it. CMC and EPS ens indicate some sort of trailing low but looks very progressive.

As I discussed in my previous post, this may be the period for the highest probability for frozen in our area from mid week through next weekend. This is clearly the most favorable window on the 18z GEFS. As for the midweek 'threat', it is still there but imo it is marginal at best, and the most likely outcome will be some showers for the coastal plain and if the wave tracks far enough north, maybe some wet snow or rain/ snow mix for NW areas. Doesn't look like anything too significant to me at this point, but I could be wrong. Sorry CMC huggers.

Beautiful evening for a few drinks around the firepit.

Looking over the latest ensemble runs for the Friday-Saturday deal.. the GEFS took a major step towards the Euro/EPS and CMC ens in emphasizing a primary low tracking into the OV and NW of our region. Something to watch(and maybe the best chance for frozen with this event the way things look right now) is a developing coastal low later Saturday as the colder air comes in. Hard to tell on the ensembles if this is due to trailing energy on the front, or a low developing offshore of the coast in response lowering h5 heights as the main trough approaches. Probably the latter. The ops are pretty messy looking with the vorticity at h5, and it will change, so not worth further analysis at this time, at least from me lol.

It's all relative but we had some decent cold this winter, mostly in January. Last winter I never recorded a temp below 20, even during Feb with snow/sleet otg and clear skies at night. I had at least 2 single digit lows this winter following the 2 bigger snow events- a low of 7 and 3. Also managed to keep snow otg for longer stretches. Part of the reason we didn't get any super cold air is the progressive nature of the pattern, which you touched on. The legit cold we did get was a 2-3 day shot then quickly modifying as the trough departed, then rinse and repeat. The longwave pattern never stayed aligned long enough to get cold air in place, and then reinforcing shots of cold. We typically need help up top for that. Even though the ens means sometimes suggested it, we never had anything close to a 2014 type delivery of true arctic air, and definitely not with any persistence.

Low of 29 here. Bring on the 60s! 70s! 80?

For the midweek potential system, we get some colder air working in behind the early week rainstorm as a piece of NS energy slides across to our north. This flattens the ridge and sets the stage for a wave to move along the boundary just to the south. Right now it looks fairly modest, and the northern/western areas of our region would be favored for some wet snow. GFS/GEFS is further south with the wave than the Euro/CMC and their ensemble means.

There are pretty big differences between the GEFS and EPS wrt the trough position at the end of next week, and thus why the EPS has the primary low pressure tracking inland/NW of our region, while the GFS/GEFS emphasizes more of a coastal low tracking along/offshore of the coast. The latter would be the colder solution and be more conducive for frozen. The Canadians side more with the Europeans at this juncture. This may again be another case of the GFS being too aggressive with advancing colder air masses at range.

Possibly. During the January period when we had some good cold available, the pattern was progressive(minimal to no blocking) so it all came down to timing, and it happened to work out for places further east with later developing coastal lows. I would argue that it was not really a true STJ though- we had a bit of a split flow at times, but the amplified pattern allowed shortwaves entering near AK to dig further southward than is typical, so in some cases those became our 'southern' waves.

Be careful with that association. Ninas can feature blocking, but they almost never have a persistent/prominent stj. That feature is characteristic of a Nino and allows for storm development further south/SW so as to have greater impacts at our latitude, in conjunction with HL blocking(encourages storms to track underneath and keeps cold locked in).

Canadian ens looks much more like the EPS than the GEFS. Who wants to ride the colder GFS/GEFS look at range?

12z EPS isn't any better. It tracks everything to our NW then brings the cold in next Sunday, so we get mild and wet followed by a couple days of transient cold and dry. The higher elevations of western VA/WV/W MD would probably see some frozen during the Thursday-Sunday period verbatim.