TheClimateChanger

This would be crazy warm for 12Z. NAM shows mid 90s late Wednesday afternoon ahead of this, but I thought the forecast overnight temperatures Thursday morning were actually more noteworthy...

I don't know. NWS PBZ seeing the potential for a "few 90 degree days" middle of next week. .LONG TERM /MONDAY THROUGH THURSDAY/... A pattern shift is then expected next week as persistent upper troughing eventually fills via an amplifying ridge across the southeastern CONUS. Long range solutions indicate potential for 500mb heights ranging between 590-594 dam, which implies the potential for a few 90 degree days by mid week. Meanwhile, with the forecast area on the northern edge of this building ridge, within continued, nwly flow aloft, unsettled conditions should remain possible through at least mid-week with ongoing chances for showers and thunderstorms.

Nailed it, I think. 84 at KPIT, and 90 in the 'Cuse right now. Looks like these forecast temps should be within about a degree or so of the actual highs.

Given it’s currently 67, and it looks clouds and showers are going to be hanging tight for at least a few more hours, even 80 looks questionable despite the long days.

Well, the app shows 92 and 94 for downtown Pittsburgh, but only 88 and 91 at Moon Township. Both of which would fall shy of the records of 93 and 92 from the old Weather Bureau office.

If it reaches 90 or better tomorrow or Saturday, it would be the fifth earliest year to reach 90+ since records have been kept at KPIT (i.e., dating back to 1953 - records moved to KPIT in September 1952 when the airport opened). Note: Not necessarily fifth earliest reading, since some of the 4 years with earlier 90+ readings may have had more than one such reading (in fact, I know that's the case for 1962). Should it reach 91 or better, that would be the second earliest such reading. All of the other early 90 degree readings at KPIT were exactly 90 degrees. The only earlier 91+ reading at KPIT was May 18, 1962. Now, in the off chance it were to reach 92 or better, that would be the first time it's ever been that hot anytime in the month of May at the airport site. Currently, the hottest May reading at KPIT is 91, which was reached once in 1962, 1987, 2011, 2012 and 2018.

Not sure the KPIT sensor will get there. Can see it stall out at 88, while Syracuse reaches 93.

Looks like it's going to be another tough summer for 90s. I noticed the NWS tweeted the temperature at their office was 82 at 1:49 p.m. The 5-minute average temperature at KPIT at 1:51 p.m., basically centered on the point measurement shared by the NWS, was 80F. I wouldn't expect the NWS office to be two degrees warmer than the airport, being just about a mile away at similar elevation in a shady suburban neighborhood versus an open airport site loaded with asphalt tarmac. Most of our 90s are like 90, 91, so if the ASOS is running a couple degrees too cool, I'd expect a lot of days topping out at 88 or 89 again. Hard to reach 90 if the actually air temperature needs to reach 92 to register that number.

On this date in 1901, the upper Ohio Valley was in the midst of one of the worst, if not the worst snowstorms, on record for the region with storm totals as high as 3 1/2 feet reported in Stark and Licking Counties. Due to the heavy weight of the snow, structural collapses were reported, rail traffic was brought to a standstill and telegraph lines were downed all over the place. The following passages describe the storm - the first from the Ohio Weather Bureau report, and the second from the West Virginia report for context on the storm. Appears northern and southern stream energy phased into a strong storm over Georgia, which tracked slowly north in to western Virginia but ran into a ridge of high pressure and stalled for most of the day, before becoming completely cut off from the flow, retrograding westward into the Ohio Valley, eventually filling and dissipating. There must have been a strong atmospheric river directed from the Atlantic through Pennsylvania and into Ohio and West Virginia and southern New York based on the widespread 3-8" precipitation totals. While the precipitation fell as a cold rain in Pittsburgh, the river crest was one of the top five of the 20th century and unlikely to be exceeded due to flood control measures put in place after the devastating flooding in March 1936. 1901 is the snowiest April on record in Pittsburgh with 13.5" but that was from the earlier storm from the 2nd to 3rd noted in the West Virginia summary. That storm also produced up to 20 or more inches of snow in the higher elevations.

This is going to be another cold rain in the 30s, while central and northeast PA get clobbered, isn't it?

Yeah, we can't win around here. In the wintertime, it's often below or near freezing but rain or wintry mix due to warm air aloft. In the springtime, its below freezing aloft but just above freezing at the surface so the snow melts in the last couple hundred feet or makes it to the surface and then melts on contact.

Looks like it is accumulating at Seven Springs.

Just switched over to wet snow here over the last 10 or 15 minutes, but it looks like the back edge of the heaviest returns are pushing northward.

I should add while the advisory for Tucker County only states up to 4 inches, the official NWS snowfall forecast map does show 6-8 inches in the far eastern parts of the county in the very highest of elevations. But I guess due to the localized nature of the heavier totals, they just stuck to the advisory countywide there.

12Z HRRR wasn't too dissimilar. I used the actual modeled ratios for this map, which were less than both the 10:1 and Kuchera maps for the ridges. And less than the 10:1 ratio map, but slightly greater than the Kuchera map for the immediate metro. Pretty much in line with what I said above (which admittedly was more conservative than the NAM 3K since I had looked at the full suite of modeling before posting). Little if any downtown, but does show up to an inch in western Allegheny and up to 2" in northern Allegheny. With again the best chances of 2"+ being from Butler County northeast. Significantly less for the ridges, but still shows up to a foot in eastern Tucker (the Kuchera and 10:1 maps both showed up to 14" in eastern Tucker).

Key takeaway is this will be heavily elevation dependent. Might be difficult to get any accumulation downtown, while some of the more elevated neighborhoods might pick up a half inch. Taken literally, some of the global models do have a few inches in the city but I'd lean towards the mesoscale modeling in this situation. The official observation site will probably see some accumulating snow later, maybe 0.5-1.5 inches. Best chance of 2"+ looks to be in the northeastern parts of the area - northern Butler, Armstrong, Indiana, Venango, Forest, Clarion and Jefferson Counties. The higher totals to the north are partly a function of elevation, and partly a function of the fact that the precipitation lingers longer there into the evening and overnight. The ridges could see much more than the official forecast if the modeling is correct.

Interestingly the NAM 3K is showing nearly 30" in parts of Tucker County, while they are under a WWA for up to 4 inches. Not much for Pittsburgh city on the Kuchera ratio map, although that's a bit misleading as that is one of the lowest numbers in the metro area due to elevation and urban heat island. The numbers are placed right over the cities and not the airport locations where the obs are taken. Most places are shown in the 1-2" range, including around the airport. More to the northeast where the precipitation lasts longer after the changeover to snow. This is the Kuchera map which generally is less than the 10:1 map, although it might be a bit more in some of the ridge locations.

I’m up in northwestern Pennsylvania (near Clarion) this morning, and there was about a quarter to a half inch of snow accumulation on some surfaces this morning.

Canadian looks the best with 6"+ northeast of the city on 10:1 ratio. However, the actual accumulation might be less.

I was looking at old photos, and we had an inch or two of wet snow last year on April 21. Also had snow showers and a slight dusting on some elevated surfaces in 2020 on May 9th. Looks like a good chance of some late season accumulating snowfall next week.

All models seem to be on board for some possible accumulating snowfall next week. Euro, UKMet, and Canadian all have 3-5 inches on 10:1, but the Kuchera ratios are lower with an inch, maybe two in spots. GFS less, but maybe still a coating to a half inch.

Lock it in gentlemen.

Oh yeah, this would be a doozy.

Only 300+ hours away...

Euro holding out hope for one more snow storm, especially north.