psuhoffman Posted January 2 Share Posted January 2 4 minutes ago, clskinsfan said: At least we have some colder air on this side of the hemisphere now. We should be able to withstand a short pac puke episode. We want the jet to extend enough to push the ridge back into western N America and establish a trough in the N Pacific. We just don't want it to go crazy like the last one. The reason we might get a relax and a cutter next week is because the jet retracts too much and we end up with nina like pacific forcing for a short time. 3 1 Link to comment Share on other sites More sharing options...
clskinsfan Posted January 2 Share Posted January 2 Its actually quite a bit colder up into PA. Which is a good sign I think. 4 Link to comment Share on other sites More sharing options...
Terpeast Posted January 2 Share Posted January 2 13 minutes ago, psuhoffman said: It’s sped up about 6 hours in the last 4 runs. this isn’t perfect but these frames are a better comparison when the storm is at a more similar spot in its pass which matters more. The change is noise imo. 18z looks slightly colder but with the 6 hour adjustment now it’s maybe an hour behind 0z so it’s a wash imo. The eps has been holding with only noise changes run to run today. Awesome, thanks for putting that together. If this does verify, its going to be a nailbiter out here. Link to comment Share on other sites More sharing options...
nj2va Posted January 2 Share Posted January 2 We can start extrapolating the NAM this time tomorrow. 5 4 3 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted January 2 Share Posted January 2 2 minutes ago, nj2va said: We can start extrapolating the NAM this time tomorrow. Thank the gods 6 1 Link to comment Share on other sites More sharing options...
Stormchaserchuck1 Posted January 2 Share Posted January 2 1 hour ago, jnis said: Hi Stromchaserchuck1..., I appreciate your's, and everybody's analysis as we close in on a potential snow threat. You seem to be interpreting some the data differently then a lot of the other experienced and knowledgeable contributors. Could you please elaborate on the meteorology regarding your last two statements. I'm hoping to expand my meteorological knowledge. Thanks! Hello, Thanks. I have been observing weather models almost daily since 2016, and I have found them to underestimate the amount of surface-layer warmth of a -PNA pattern more times than not. If you look at a historical composite of DCA or BWI snowstorms, the strongest feature with a 50/50 low is a GOA/Aleutian island trough. On the models we have that needed trough digging into the West Coast US, instead. Here is a 500mb correlation map with January N. Pacific: https://ibb.co/sJPTkdB https://ibb.co/10d2BGN As you can see, that N. Pacific region posts a +0.53 500mb correlation over DCA/BWI at that time. Here is the 500mb map of 1 day before the storm moves NE. The cold air is pretty cutoff. https://ibb.co/tsF0xLh In my experience, places along I-95 do not do well in these setups because the surface temperature ends up reaching 35-36 degrees. I know we are getting closer to where the entire N. Hemisphere pattern is of less concern, but it is still 5-6 days away, which I find is still valid for a trend away from snowstorm (I-95). I'm just saying this same scenario has happened that way 9/10x recently, so watch for the same model error/adjustment. I would say mostly rain to <1" for Balt/DC. 3 Link to comment Share on other sites More sharing options...
aldie 22 Posted January 2 Share Posted January 2 4 minutes ago, Terpeast said: Awesome, thanks for putting that together. If this does verify, its going to be a nailbiter out here. It hasn't really snowed much since you have been back has it? Leesburg is definitely a tad better than Ashburn. After I left Leesburg I ended up in Lansdowne and it was always just a little less. It will be interesting how Aldie is as I'm south but more west. This could be a fun one 1 Link to comment Share on other sites More sharing options...
Terpeast Posted January 2 Share Posted January 2 18 minutes ago, aldie 22 said: It hasn't really snowed much since you have been back has it? Leesburg is definitely a tad better than Ashburn. After I left Leesburg I ended up in Lansdowne and it was always just a little less. It will be interesting how Aldie is as I'm south but more west. This could be a fun one I’ve only seen measureable snow twice and both were half an inch or less. Leesburg or west of 15 is probably better than Ashburn, but coming from Vienna, Ashburn probably will do better in i-95 fall line setups like this one 2 Link to comment Share on other sites More sharing options...
WEATHER53 Posted January 2 Share Posted January 2 2 hours ago, psuhoffman said: We had this discussion many times over the years. I hate when it becomes an argument over definitions. I could care less what we call them. The problem is for the "purists" that define any transfer as a miller b, we then HAVE to differentiate between northern stream dominant SW's that transfer and STJ dominant transfer storms. The best definition system I've seen classifies the later as "hybrid" systems. And by that definition system our best storms are almost all hybrids. Pure miller a storms usually are trucking and moving too fast to dump prolific totals. The transfer process actually slows down the system some, plus often when a primary west of the apps transfers its because its blocked to some extent. We also run the risk of being too far west for a pure miller a. They sometimes end of coastal scrapers for our area and nail NYC, especially in a Nina! A primary into the TN valley pretty much guarantees we don't miss out on the party, so long as it transfers in time for us to stay cold enough. Additionally getting the wave to amplify to our SW opens the door to prolific WAA snows before the storm even gets going. Our really big storms are when we get a foot of snow from overrunning before the coastal even gets going. Miller a/b hybrids are actually our best storms. But the people that classify everything as A/B scare the crap out of some when they classify them as miller b and they suddenly think of every NS jump storm that screwed us over and hit New England. I know you know this, we've had this conversation before...but thought it was time to bring it up again for all the new members since the last time we got to actually go over this...since its been so freaking long since we actually got to discuss a legit snow threat in this kind of detail. This is great info and you are right about getting nervous in transfers. I love how you break the difference in the nature of transfers down to NS vs low moving from south into TN and then transferring , Did I get that right? Thsnks 1 Link to comment Share on other sites More sharing options...
87storms Posted January 2 Share Posted January 2 Hello, Thanks. I have been observing weather models almost daily since 2016, and I have found them to underestimate the amount of surface-layer warmth of a -PNA pattern more times than not. If you look at a historical composite of DCA or BWI snowstorms, the strongest feature with a 50/50 low is a GOA/Aleutian island trough. On the models we have that needed trough digging into the West Coast US, instead. Here is a 500mb correlation map with January N. Pacific:https://ibb.co/sJPTkdBhttps://ibb.co/10d2BGNAs you can see, that N. Pacific region posts a +0.53 500mb correlation over DCA/BWI at that time. Here is the 500mb map of 1 day before the storm moves NE. The cold air is pretty cutoff. https://ibb.co/tsF0xLh In my experience, places along I-95 do not do well in these setups because the surface temperature ends up reaching 35-36 degrees. I know we are getting closer to where the entire N. Hemisphere pattern is of less concern, but it is still 5-6 days away, which I find is still valid for a trend away from snowstorm (I-95). I'm just saying this same scenario has happened that way 9/10x recently, so watch for the same model error/adjustment. I would say mostly rain to We need to adjust the slope of the regression line towards zero to account for the weekend rule.I’m kidding, but I do think there’s been times where cad (assuming that’s in play) has been under-modeled. That, along with a quicker arrival of precip, might offset some of the initial temp issues. 1 Link to comment Share on other sites More sharing options...
Ji Posted January 2 Share Posted January 2 18 minutes ago, Terpeast said: I’ve only seen measureable snow twice and both were half an inch or less. Leesburg or west of 15 is probably better than Ashburn, but coming from Vienna, Ashburn probably will do better in i-95 fall line setups like this one that rain snow line has shifted since the 80's quite a bit. I used to be comfortable living in Herndon...then i think it went to ashburn and now its just wests of Leesburg ... scary 1 Link to comment Share on other sites More sharing options...
jnis Posted January 2 Share Posted January 2 36 minutes ago, Stormchaserchuck1 said: Hello, Thanks. I have been observing weather models almost daily since 2016, and I have found them to underestimate the amount of surface-layer warmth of a -PNA pattern more times than not. If you look at a historical composite of DCA or BWI snowstorms, the strongest feature with a 50/50 low is a GOA/Aleutian island trough. On the models we have that needed trough digging into the West Coast US, instead. Here is a 500mb correlation map with January N. Pacific: https://ibb.co/sJPTkdB https://ibb.co/10d2BGN As you can see, that N. Pacific region posts a +0.53 500mb correlation over DCA/BWI at that time. Here is the 500mb map of 1 day before the storm moves NE. The cold air is pretty cutoff. https://ibb.co/tsF0xLh In my experience, places along I-95 do not do well in these setups because the surface temperature ends up reaching 35-36 degrees. I know we are getting closer to where the entire N. Hemisphere pattern is of less concern, but it is still 5-6 days away, which I find is still valid for a trend away from snowstorm (I-95). I'm just saying this same scenario has happened that way 9/10x recently, so watch for the same model error/adjustment. I would say mostly rain to <1" for Balt/DC. Thank you for the more detailed response. I appreciate you time. I see what you mean based on the last map you posted. Hopefully, there will be enough cold air for 95 east to get in on the action, but a rain/ snow line setting up near the 95 corridor seems fairly typical. Happy New Year. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 2 Share Posted January 2 21 minutes ago, WEATHER53 said: This is great info and you are right about getting nervous in transfers. I love how you break the difference in the nature of transfers down to NS vs low moving from south into TN and then transferring , Did I get that right? Thsnks Yes, there is a HUGE difference between a wave coming at us from the southwest tracking into the TN valley before transferring to a coastal and a northern stream SW diving out of the NW that develops a coastal storm. 4 Link to comment Share on other sites More sharing options...
Fozz Posted January 2 Share Posted January 2 Just now, psuhoffman said: Yes, there is a HUGE difference between a wave coming at us from the southwest tracking into the TN valley before transferring to a coastal and a northern stream SW diving out of the NW that develops a coastal storm. Was Feb 10, 2010 a purely NS-driven storm? Or did it phase with any STJ component? Link to comment Share on other sites More sharing options...
Ji Posted January 2 Share Posted January 2 If we didnt have this storm....where is the next threat coming from? Nothing really stood out looking at the long range? Maybe the 12th/13th? 5 Link to comment Share on other sites More sharing options...
nj2va Posted January 2 Share Posted January 2 1 minute ago, Ji said: If we didnt have this storm....where is the next threat coming from? Nothing really stood out looking at the long range? Maybe the 12th/13th? 2 days ago, this threat didn’t pop up on most people’s radars. 1 Link to comment Share on other sites More sharing options...
ravensrule Posted January 2 Share Posted January 2 6 minutes ago, nj2va said: 2 days ago, this threat didn’t pop up on most people’s radars. Do you really have to encourage him?. 1 1 Link to comment Share on other sites More sharing options...
rjvanals Posted January 2 Share Posted January 2 7 minutes ago, nj2va said: 2 days ago, this threat didn’t pop up on most people’s radars. @psuhoffmanand a few others honed in on this window around Christmas Link to comment Share on other sites More sharing options...
Maestrobjwa Posted January 2 Share Posted January 2 9 minutes ago, Ji said: If we didnt have this storm....where is the next threat coming from? Nothing really stood out looking at the long range? Maybe the 12th/13th? Why not just...stay in the present for a moment? No "if we didn't"...we DO have this storm to track. And the 12th/13th is almost 2 weeks away and we wouldn't be able to identify a specific threat right now anyway. Just enjoy now! 1 Link to comment Share on other sites More sharing options...
Deck Pic Posted January 2 Share Posted January 2 This is the stuff our dreams are made of. Time to close. 10 Link to comment Share on other sites More sharing options...
psuhoffman Posted January 2 Share Posted January 2 14 minutes ago, Fozz said: Was Feb 10, 2010 a purely NS-driven storm? Or did it phase with any STJ component? That was one of the oddest cases of any HECS storm for the mid atlantic. Initially there was a STJ system crossing the 4 corners as a stronger cut off system dove into the Dakotas out of Canada. They phased over the upper midwest and 99% of the time that would have been game over for us except we had maybe the most ridiculous block ever preventing anything from cutting and forced the closed upper low to continue southeastward. It did still have a STJ connection, there was a weak wave down in the gulf with a moisture feed up into the system but the dominant feature was always the NS system that dove due south out of Canada then turned southeast and continued southeast right across VA. I guess I would categorize it as a hybrid but it was as close to a NS miller b as any in that subset. That setup would never work again unless we had that kind of block. Some images from that system 5 Link to comment Share on other sites More sharing options...
JenkinsJinkies Posted January 2 Share Posted January 2 1 minute ago, psuhoffman said: That setup would never work again unless we had that kind of block. I'm guessing that's why Feb 2010 was a 1 in 150 year event. 3 Link to comment Share on other sites More sharing options...
Buddy1987 Posted January 2 Share Posted January 2 Would like to think Icon was another good shellacking.. skips between hrs 108-126 as of this moment. Looks like track would he ideal for most here. Link to comment Share on other sites More sharing options...
LP08 Posted January 2 Share Posted January 2 ICON looks good, minus the fact it’s missing some important panels lol. Link to comment Share on other sites More sharing options...
LP08 Posted January 2 Share Posted January 2 1 minute ago, LP08 said: ICON looks good, minus the fact it’s missing some important panels lol. Deforms are fun. 3 Link to comment Share on other sites More sharing options...
Maestrobjwa Posted January 2 Share Posted January 2 1 minute ago, LP08 said: ICON looks good, minus the fact it’s missing some important panels lol. Dang it ICON...it's always the exact panels you need, lolol Link to comment Share on other sites More sharing options...
psuhoffman Posted January 2 Share Posted January 2 22 minutes ago, Ji said: If we didnt have this storm....where is the next threat coming from? Nothing really stood out looking at the long range? Maybe the 12th/13th? It depends how things turn after the cutter on the 10th, which we still possibly could start as some frozen if we get lucky with the details. But after that there is a huge difference in how the EPS and GEFS progress the pattern with the GEPS somewhere in the middle. Neither is stacked immediately after although if the EPS is correct I definitely could see us getting some frozen from a progressive boundary wave in the 12-17th time period, although another cutter is possible if something phases and is too amplified. If the GEFS is right almost anything, even a progressive wave will cut well west of us in this time period. After that again depends on which guidance wins out...the EPS slowly shifts the trough southeast under the block as the pacific resumes a more nino look. Eventually by the 18th or so we could be chasing a big storm again. The GEFS on the other hand goes off the rails and the extended goes towards a full nina look and even flips the AO/NAO positive and frankly looks like 2020 and last winter by late January and implies winter is over after this Jan 7 storm. I do not think the GEFS is correct. The EPS matches my expected progression for the season so why would I favor the less accurate guidance that goes against history. But....I still will feel better when it caves! Thought it was in the process of caving yesterday then it reverted to full on disaster. I expect it will cave soon but I will do a shot in relief when that happens. 1 Link to comment Share on other sites More sharing options...
psuhoffman Posted January 2 Share Posted January 2 2 minutes ago, LP08 said: ICON looks good, minus the fact it’s missing some important panels lol. it always does that lol 1 Link to comment Share on other sites More sharing options...
Ji Posted January 2 Share Posted January 2 25 minutes ago, nj2va said: 2 days ago, this threat didn’t pop up on most people’s radars. not true--i have been looking at the Jan 7th window since Dec 22 1 Link to comment Share on other sites More sharing options...
nj2va Posted January 2 Share Posted January 2 1 minute ago, LP08 said: Deforms are fun. Missing a few panels but doesn’t seem like there’s an OH valley low so I like that. 4 Link to comment Share on other sites More sharing options...
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