Blizzard of 93

Great discussion this morning from CTP. “.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... A major winter storm will impact central PA Wed afternoon through Early Thu morning, with snow accumulations of 1-2 feet expected, and snow rates as high as 2-4 inches per hour Wed night. Snow will move into the southern tier by late morning and then overspread the rest of central PA through the afternoon. Snow will start off light but quickly become moderate in intensity, as the primary low moving into the Ohio Valley forces large scale WAA and isentropic ascent over the cold air associated with a nearly 1040mb high pressure system in southern Quebec. This setup has all the hallmarks of a textbook Northeast snow storm, with dewpoints in central PA starting in the low teens Wed morning and a clear signal for cold air damming keeping a large wedge of cold air at low levels. Heavy snow bands will take shape during the evening hours on Wednesday. The ECMWF and NAM deterministic models suggest the easterly jet to the north of the intensifying 850mb low may intensify to as strong as 60-70 kts as it moves over eastern PA by 06z Thu. Historically, many of the heaviest snow events in this area have occurred just west of strong easterly wind anomalies, where convergence and frontogenesis forces intense upward motion within cold air. As snow bands move through central PA Wednesday night, localized snow rates of 2 to 4 inches per hour are a reasonable expectation. Overall, a consensus/mean of all deterministic and ensemble models has been remarkably consistent in painting the stripe of heaviest snow along an axis from south central PA northeastward into interior New England. We bumped this area up into the 18-24 inch range in our latest grid update. However, individual deterministic models continue to vary on the exact placement of the heaviest snow. It is certainly possible that the location of the axis of heaviest snow may be realized farther north/west... closer to the I-80/I-99 corridor... similar to what the 00z ECMWF deterministic run suggested. Snow to liquid ratio (SLR) may also be conservative here, as the National Blend of Models suggests a SLR near 11, but other techniques suggest the SLR may be as high as 15:1 along and north of Interstate 80. If this is the case, and QPF ends up being as high as the 00z ECMWF suggests, max totals in excess of 20 inches could be realized in the State College area. On the other hand, the "bust potential" in the Lower Susq (esp. S of Harrisburg) might be that less snow ends up falling due to the presence of a nearby dry slot, or warm nose of above freezing temperatures that changes the snow over to sleet for a period early Wed night. The 3km NAM and HRRR have hinted at these "flies in the ointment" in recent runs. For now, these are still just things to consider as worst case/best case scenarios. We will continue to monitor trends closely, but overall confidence remains high for 1-2 feet of snow across a large portion of central PA. The storm will be relatively quick moving, with most places seeing precip for 18-24 hours. Nonetheless, with cold temperatures in place, good SLRs, and very strong frontogenesis, this should end up being the most significant snowstorm for most of the area since November 2018... and for some areas, perhaps one of the heaviest snow events in the past 5+ years. It also may rival some of the record 1-day and 2-day December snow totals. For reference, the December 2-day record snowfall at Harrisburg is 13.9 inches, set in 1961.“

Here are the 6z Euro snow maps.

The 6z Euro brings the goods once again to CTP. It shows some mixing in York & Lancaster at the height of the storm, but they go back to heavy snow once the low makes the turn to the east towards the Delaware & NJ coast. Just as @Cashtown_Coop said, someone in here could get over 20 inches with this storm!

Here is the 0z EPS snow map, which these ensemble maps are based on just 10-1 ratios.

Here is the EPS low track with member locations. The mean is in a good spot despite some wild card way west & east solutions. The best part is that the lows head east once reaching near Delaware.

Here is the 0z Euro Kuchera ratio map

6z GFS looks for all of CTP

Same here...and it’s going to be a long couple of days ahead between pre game, event & then storm clean up!

Here are the 0z individual ensemble members on the 18z GEFS. Lots of major hits in there for varying parts of CTP among the members.

The 0z GEFS stepped up snow amounts by 2 to 3 inches over the 18z GEFS run for the LSV!

I just realized that Harrisburg got officially on the snow board this year with .2 inches today.

Here is a look at the full RGEM. The Kuchera ratio is crazy here on yet another model. Someone in this region is going to get demolished by this storm.

The winds are really ramping up on the 3k NAM as well...!

Cut those totals in half and I am thrilled!

Great point and well said! I remember a day or 2 before the storm saying to some people that I had never seen 30 inches on a snow map for my backyard so close to the day of an event.

Exactly! That’s the old saying... Its game on when those 2 agree!

Ummm... and the 3k NAM is still snowing on most of us at the end of the 60 hour run!!! It would probably tack on a few more inches of snow to those outrageous maps!!!

No words needed...

I stand corrected.... Kuchera?!?!! Stand by for maps & brace yourselves!

How about 30 “ ?!?!?! The 3k NAM is out of this world!!!

Yes! This!

Not our region, most of our concerns are not the same as theirs!

The 18z EPS still looks great for CTP!

How are your trash cans doing?

The low again gets to southern Delaware and then starts crawling east from there to off of the coast and continuing eastbound! This run, any mixing in York & Lancaster goes back to all snow as the low turns slightly to the east and off the coast!