Hurricane Agnes

Temp continues to be non-diurnal and has risen to 41 with dp 41. The light to moderate rain is still ongoing and I currently have 0.74" for the event and happened to also notice that I also have 52.00" for the year so far at post time, which is way above normal! The winds have started to pick up a bit too.

Temp still rising here in NW Philly and now up to 40 with dp 39 and 0.61" in the bucket with continued light rain. Low is getting closer to the coast so will see how much the coastal fires up (if it doe).

12z EC Christmas Day look -

Still getting light/moderate rain with temp now up to 39 and dp 38. Have 0.46" of rain so far for the event. The low has been slow going.

Looks like the Canadian bombs it out but still south/east. Waiting for the Euro to get to those hours.

Still all rain here in NW Philly with temp up to 35 and dp 35. Have 0.26" in the bucket.

NBM splits the difference and suggests almost (but not quite) Warning level amounts for Philly metro.

Finally got some bucket-tips and have 0.04 so far (edit - just tipped again) with this round 1 (pre-coastal) and the light rain continues. Temp still hanging at 34 and dp has now crept up to 32.

Down to very light misty rain here. Bucket still not tipped yet but the earlier IP was enough to add a very light coating on car tops. Currently bopping between 33 and 34 with dp 29.

Now getting plain rain although not enough yet to tip the bucket. Temp still holding at 34 but dp continues to creep up and is at 29.

My Upper Darby sis just texted that she is getting sleet with flakes mixing in and a temp of 33. The precip. just started up here and am getting pingers with some rain mixed in, and it's 34 with dp 28.

Leading edge is just overhead here but getting virga as the air was pretty dry just ahead of it. It's starting to moisten up now and temp is 34 with dp 27 and overcast.

6z GFS has some token stuff on the ground in Philly metro (I think the NBM is discounting this run at the moment).

Don't know if I need stronger coffee but it looks like the 6z GFS just made a slider out of the 12/23 storm (suppression?) and now it is OTS.

I created an OBS thread for the event - We are starting out at or slightly below freezing IMBY, which is actually a bit "warmer" than the past couple mornings (some due to the cloud deck vs previous mornings).

Current obs - Tem 32 with dp 24 and overcast.

That's what our Streets Dept. here in Philly says - it's done to keep the snow from sticking to the road surface although it also lowers the freezing point of any melted precipitation as long as there is a decent concentration of it and no heavy rain to wash it away. But then they also claim they don't plow here until there is supposedly 3" or more that has accumulated on the roads and often by then, the damage is already done after the accidents pile up from slipping and sliding cars. And if you have like what is forecast here - heavy rain - (and worse, rain on either end of the event time frame) putting any type of treatment down means it all gets washed away. So I guess it's all in the timing of it with a focus needed on getting the overpasses and bridges treated well.

18z GFS has a little something down here along I95 but the kicker is the last panel a couple days before New Years. lol

I was just up your way around the time you posted this (at Assi Plaza) and saw the tell-tale "storm incoming" hazy deck of cirrus with sun trying to blaze through. Actually made it up to 40 as a high (degree warmer than yesterday's high) after a low of 27. I saw Springfield Township did some brining earlier today. Am thinking it's more to reduce the potential for black ice with the event supposedly getting going during morning rush after a cold overnight and antecedent cold roads... plus a forecast of some kind of mix to start (including IP) for down this way. I know they use their own trucks to do it. Also wanted to throw the 12z Ukie in for its snow forecast for this upcoming event through to Saturday.

18z hi-res EC (only up to 90 hours) shows the low really tucked in but then still wraps cold air in over I95 (but I expect it means some kind of mix).

To compare - the 18z NBM -

18z GEFS showing an obvious north focus for the greatest amounts of frozen by the weekend.

Could be a mid-range blip. Will have to see what the 0z says... 2009 - 2010 was an El Nino winter but anytime you have some kind of tucked coastal, it's gonna wrap in too much warm air just inland. If you get a juiced up clipper with enough intensity and antecedent cold air, you could get walloped as the ocean moisture wraps in around the low and loses the battle with the cold air as the low approaches the coast. This thing almost looks like an overrunning precip event pulling moisture out of the GOM first before it spins something off the coast.

It's not just La Nina and a "warm" ocean. It's still December and unless there are some really anomalous cold outbreaks early in fall, the ocean isn't really going to hit it's coldest temps until well into February, which is the typical lag.

18z GFS is depicting some wrap-around snow as the low departs Friday/Saturday. As some quick obs, I made it up to 41 today after a low of 33. Had a little drive-by rain shower early this morning for 0.01" and with 0,11" yesterday, ended up with a 0.12" 2-day total. Skies were unsettled in general today with the sun fighting to appear and then giving up. Currently 37 with dp 31