MillvilleWx

lmao I wish

Hey Voyager! Your area is is the Central PA north of Turnpike to 99! Big area, but I felt it would be pretty uniform there. Hope that helps and hope you're doing well!

Midland, Texas lol

Alight y'all. It's that time where I come in and make a forecast for my PA brethren. First off, this storm is quite the juicy storm with PWAT's running 1-2 standard deviations above normal across the south and into the Tennessee Valley. This moisture will advect northward into a solid polar airmass with low dew points capable of producing a sufficient wet bulb once the precip arrives. This will keep the entire region as snow for the morning with the only warm spot in the state in the SW corner due to the strong WAA on the western side of the Apps. Between 10-14z, snow will break out across areas from west-southwest to the east with the last spots to see snow east of the 83 corridor. Strong low and mid level frontogenesis will move into south-central PA and the Southern Laurels in the morning with heavy snowfall rates for several hours expected. The higher terrain around 99 will be the best area for coupled frontogenic forcing, as well as the orographic enhancements of the Allegheny's. Strong mid level front will motion to the northeast into CPA, but there will be a cutoff of the greatest forcing potential over the area, and that looks to lie just north of I-80. Further to the east, WAA regime will supply a solid area of snowfall, but the strength of the jet between 850-600 mb will eventually shift the focus over to sleet, and the question lies, how quickly can this occur. Now, given the rates associated with the 700mb frontogen, heavy snowfall might counter-act the initial warm surge aloft, allowing for a prolonged period of rimed aggregates to fall across Southern PA up to the turnpike. Models are beginning to the potential with even the longer range HRRR indicating the evolution further south into Central MD. I think what will occur is a very prolific thump for areas like HBG/THV/LNS with the best focus west of the Shenandoah. Sleet and ZR will ultimately win out by late afternoon and continue through storms end with plain rain a distinct possibility for areas east of I-83 and south of the turnpike. My forecast is a gauge on the current trends in guidance and the overall synoptic setup evolving. I might be conservative in some spots, but I'd rather bust a little low. Accumulations will be snow/sleet and ice accretion. Laurels: 6-12" with 0.25-0.50" ice (Jackpot of up to 14" possible) HBG down the 81 corridor to Chambersburg: 5-9" with 0.1-0.3" ice MD Line from north of Hagerstown over to SE York Co: 5-8" with 0.1-0.25" ice THV: 5-8" with 0.1-0.25" ice Lancaster Co South of Pike: 3-6" with 0.1-0.25" ice Lancaster Co North of Pike: 4-7" with 0.1-0.3" ice Central PA north of Turnpike over to 99: 5-9" with 0.1-0.2" ice I-80 corridor: 3-7" with T-0.1" ice Hope everyone enjoys the snow!

34/24 with clearing skies and scattered dust

BWI: 3.5” IAD: 5.4” DCA: 2.9” RIC: 1.2” Tie: 1.32”

Hey Canderson! You sent the bat signal lol. I’ve been posting in that thread and looking into my home area more since I have a lot of family friends down there that ask for my forecasts. So I stay in tuned. I was actually going to pop in this evening and give you my thoughts after I look at more up there. Been busy with NWS. I go for my radar certification next week in Norman and actually take my Workshop Primer today. I’ll give y’all the scoop tonight! Looks snowy and icy, that’s for sure. Talk to you all tonight! .

ARW has a known wet bias and NMM actually can run dry. They are used in ensemble packages and are better utilized for convective purposes. .

Thought I'd share something in regards to surface temperatures for tomorrow evening which will be a wild card in the extension of frozen precip. Take a look at the GFS trends in surface winds and temperatures compared to the Nam 3km. Notice how the winds on the GFS are breezy out of the south-southeast and the Nam 3km is light out of the east with a much more defined CAD wedge. This is the reason for the GFS trending to all rain sooner compared to the higher resolution guidance. The GFS weakens the surface inversion significantly and allows a deeper mixing of warmer air into the lower profile. 3km on the other hand holds on and the shallow depth of cold air allows for a prolonged period of ZR across a good chunk of the sub-forum (Mainly west of the fall line). Climo will undoubtedly have some impacts on how the event transpires, like always, so if you know how temps behave in WAA regimes like this, you can probably guess what's going to happen. The main question right now is the initial thump for snow and the timing of the strongest low to mid level frontogenesis and the placement of best banding to help alleviate the warmer air mixing into the profile. Best snow potential will run from 9z in Central VA to as late as 18z up in the northern part of the sub-forum. Added orographic enhancements will likely occur as well, so mini jacks will be possible, but we won't know where that will occur until game time. General climo favors Parrs Ridge, Catoctins, and areas along I-81 out to Western MD and high country for WV. Likely will make some adjustments to my first call from yesterday on storm totals based on latest guidance.

That's probably what they and WPC went within during collaboration because it does fit their forecast. I refrained from making a final call on this storm because of any minor adjustments in the placement and strength of any synoptic features will cause significant shifts in the snow maxima and final distribution of sleet/freezing rain. I want to see all guidance before making any final calls today. Probably will not happen until the evening for me since I work and I'm going to be crazy busy today.

Last Model Diagnostic Discussion from WPC last night indicated the NAM is the furthest north with the expected QPF maxima compared to other guidance, but is within the general ensemble spread, so it was maintained. The overall pattern evolution is a weighted average of all models, so no disclaimers made given the trends of last nights runs. If anyone wants a link to the discussions, here's where to find them. https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdhmd

The NAM Nest is basically my first call forecast. The heaviest precip coincides with the jet at 700mb. Once that enters the area, precip blows up, but serious WAA kicks in and changes everyone over. The farther north you are, the better. Pretty typical for this setup.

There was 40" between New Haven and Stamford along I-95. We came back home the night after the storm ended and we cut down 95 to get home. It looked like a bomb went off. Cars stranded in the middle of the road with well over a foot in spots on 95. They were using multiple plows and front end loaders just to clear I-95 it was so bad.

No question that storm was worth it. One of the better blizzards I may ever see. I was positioned in Waltham, Mass, just west of Boston and the loop. Watching those bands on radar come into the region one after the other was a site to behold. My dad talks about '83. Said it's still to this day the biggest flakes he has ever seen.

It can drive one crazy, and the forecasters at the offices get pretty crazy over the constant collabs and stuff too. Trust me haha. Just know, there's a pretty hefty process involved with significant winter wx. Lot of discussion behind the computers. LWX, CTP, Blacksburg and Pitt will all have their hands full.

We're starting to see the goal posts narrow on the qpf max in the front end thump. If everything holds, could be a great event even in DC. You setting up shop in center city?

I went to school in CTP's coverage. Trust me, LWX was better with things. And those collab calls have pretty good detailed discussions with lots of feedback from both the WFO and WPC. It isn't just all models. In fact, taking a look at the Super Plume data, they are slightly more aggressive than guidance. They are handling this well, and this certainly isn't the final call for them. They can make adjustments when necessary up until it starts, then they adjust given radar, satellite, and observed trends. There's so much work involved with a winter wx scenario, it's not even funny. Only thing worse is severe imo.

I know this is beer, but I think you would appreciate this one. Erie Brewing Co. has a beer called Derailed Ale. It's a black cherry cream ale. Silky smooth finish with wonderful cherry notes. Had it at a brewhouse in PA back in January when I visited some friends near Ephrata. Best freakin beer I've had imo. Elliotness is second on my list.

I've had 4"/hr rates twice in my entire life. 4.25"/hr in the crazy thundersnow, deathband in the 2006 coastal, and Feb 2013 in Boston for the blizzard (Nemo) up there. 4"/hr was the max up there, but we had 3 separate 3"/hr bands. It was nutty.

They change it due to new data, collaborations with WPC and neighboring offices to maintain some continuity. They don't do it because they feel like it.

Given the general setup, I don't see 4"/hr a possibility. However, 2"/hr is certainly doable, maybe even a touch more. 4"/hr is saved for convective stuff typically found in bombing surface lows within the deformation zone.

I agree if it's moderate to heavy rain at temps near 31-32, it's not going to do much. Moderate at 29-30 is closer to something nasty. Light rain and temps 32 or lower will be serious issues. I think the back end of the storm will be the time frame where most ZR occurs. Still a saturated lower boundary layer heading into 0z Thursday. Freezing mist will make things nice and icy NW of the fall line. Either way, travel on Wednesday, anytime of the day will be ugly.

90th percentile according to forecast for IAD on 12z Wednesday. Easily 2 STD above normal. Crazy moisture fetch straight out of the Gulf.

Here's pivotal. It's pretty robust area wide.

Both NAM's are showing an abundance of precip over the region. No shortage of QPF to work with. 3k showing over 2" along the 81 corridor. Could be very ugly anywhere west of 95