Blizzard of 93

This is the best GFS run yet for the LSV....just wait until @pasnownut sees this run for his backyard!

That’s the best GEFS run yet...wow!

The 0z EPS still looks good and even improved slightly for our southeast crew.

0z Euro still looks good for all of CTP. I added the total precip map to give an idea of where the max zones look to set up this run. It also indicated very little mixing in the LSV this run.

Here is the 0z UKMET...the 0z party continues for CTP.

Oh yes, I want thunder snow too! @MAG5035 or @MillvilleWx or @psuhoffman How is the thunder snow chance looking now?

My favorite part of this...!!! * WHAT...Heavy snow expected. Total snow accumulations of 10 to 20 inches with the highest totals between Harrisburg and Huntingdon.

CTP just updated their Winter Storm Warning! Winter Storm Warning URGENT - WINTER WEATHER MESSAGE National Weather Service State College PA 1113 PM EST Tue Dec 15 2020 PAZ024>028-033>036-056-057-059-063>066-161615- /O.CON.KCTP.WS.W.0003.201216T1500Z-201217T1200Z/ Cambria-Blair-Huntingdon-Mifflin-Juniata-Somerset-Bedford-Fulton- Franklin-Perry-Dauphin-Lebanon-Cumberland-Adams-York-Lancaster- Including the cities of Johnstown, Altoona, Huntingdon, Mount Union, Lewistown, Mifflintown, Somerset, Bedford, McConnellsburg, Chambersburg, Newport, Harrisburg, Hershey, Lebanon, Carlisle, Gettysburg, York, and Lancaster 1113 PM EST Tue Dec 15 2020 ...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO 7 AM EST THURSDAY... * WHAT...Heavy snow expected. Total snow accumulations of 10 to 20 inches with the highest totals between Harrisburg and Huntingdon. * WHERE...Southern Pennsylvania. * WHEN...From 10 AM Wednesday to 7 AM EST Thursday. * IMPACTS...Travel could be very difficult to impossible. The hazardous conditions will impact the Wednesday evening commute. * ADDITIONAL DETAILS...Bands of heavy snow with accumulation rates of 2 to 3 inches per hour are likely late Wednesday and Wednesday night. The heavy snow could mix with sleet for a time Wednesday night, mainly over York and Lancaster Counties.

Boom! 0z GFS 10-1 map & Kuchera ratio

Not just him... All of CTP! Forum wide crowd pleaser!!!

Yes, those 3k NAM snow maps that I just posted on the last page drop the hammer on Harrisburg & all of I-81 in PA. The hourly panels were spectacular.

Yes! That would be awesome! Bring it!

The 3k NAM is an I-81 crusher !!! Harrisburg and Carlisle up through Northeast PA is buried this run!

The 18z EPS looks good for all of CTP.

Just to see the beauty of it again... here are the 18z Euro snow maps.

As the low pivots east, everyone is all snow through daybreak on Thursday.

While we wait for 0z runs tonight, here is a closer look at the 18z Euro. Some mixing gets into the southern tier at the height of the storm, but from the turnpike on north, this run stays all snow.

18z GFS 10 to 1 and Kuchera

Here is the latest CTP expected snow map

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