USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 Oh ok lol sorry about that Ray. I know a little about it other than inversion heights. Living on Cape Cod you need to know certain weather events that happen. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 This OES potential has a much higher chance of occurring now then previous events, GFS shows over .25" of QPF within OES event, shows a strong signal for this event. 850mb temps around -10C to -12C throughout the event, with 10-12C SSTs northeast of Cape Cod and delta Ts near 22-24C, equals intense instability, leading to thundersnow potential and high snowfall rates, something like we have seen with Lake Effect events in the past. Also convergence in the lower 5,000 feet along with high inversion heights above 850mb and SBCAPE near 300j/kg+ or Ocean induced Cape values about 400j/kg leads to higher snowfall rates. Low level convergence with 850mb winds out of the NNW or N and throughout the bottom 5,000 feet if wind aligns leads to singular intense snow band, rather than three or four less intense sheared bands of snow. Still models including the GFS and EURO show big Northerly wind event. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 27, 2015 Share Posted December 27, 2015 Oh ok lol sorry about that Ray. I know a little about it other than inversion heights. Living on Cape Cod you need to know certain weather events that happen. Certainly. We all have our fetishes....often dictated by our local weather phenomena. I love coastal fronts.... Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 Pattern looks better for some storminess after day 10, but right now within the next 10 days I will take a good OES event over anything else now. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 18z GFS is rolling Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 LOL, I think the models will come through for me, and we will get our event come not this Monday but next Monday. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 27, 2015 Author Share Posted December 27, 2015 18z GFS further north with initial low, which means winds are more northwesterly and not northerly, I'm not worried. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 00z GFS maintains OES threat come seven days from now. January 4th looks to be the day in which -14C to -16C 850mb temps invade CHH sounding so we could have very intense snows. Stay tuned. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 GFS would produce delta ts near 24-26C which is extreme instability, actually the threshold for OES events is 22C for extreme instability we have that, we also have 70-100% humidity through 850mb which means the inversion heights are higher than 850mb, which equates to 5,000+ feet of equilibrium heights. SECAPE will be greater than 300j/kg for a good event more likely 500j/kg maybe even higher. Also winds might be a significant factor which is the reason we don't get a lot of snow in any one location, because they are always variable we won't get a ton of snow over any one location like the Tug Hill Plateau. However this event could be the difference, the one that produces more than a few inches of snow, we just need the winds to come out of the north for like 24 hours, just that and we are golden for a WSW. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 I'm guessing the 00zz EURO wasn't as kind with the OES setup as the 12z run was, any QPF over CHH? Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Storm for day 7 progs Euro (1.5% chance for a nor'easter) GFS (0.5% chance for a nor'easter), pattern is displaced to the southeast, favored by a strong +PNA presence collocated with -AO polar vortex on this side of the northern hemisphere. Ridge axis is far enough west to preclude any out to sea solution, however location of polar vortex troughing leads to crashing heights off the East Coast. This leads to little to none shortwave or long wave ridging ahead of any shortwave trough that wants to amplify on the East Coast. So any positively tilted shortwave troughs that look promising over northern Ontario, Canada that dive into the OH Valley show little to no promise given crashing heights off the East Coast east of the shortwave where ridging would be preferred. Euro shows more promising shortwave in tact, but little to none ridging east of the shortwave leads me to believe the models believe the pattern will be suppressed and too far east as trough axis is on the eastern seaboard compared to OH Valley location which is favorable for east coast nor'easters. Also baroclinic zone will be displaced to the east, so no wealth of moisture will be present precluding the options the low pressure and shortwave has to get moisture flowing into the cold air dome. One thing is certain, we will get very cold from January 1st through the 6th. Below normal temps likely on MOnday the 4th through the 6th with 850mb temps around -15C regionwide, with -12 to -15C along the coastal plain and -15 to -18C central New England and -20C to -25C across Northern New England. Such a pattern displaced to the southeast leads me to believe so is the storm track and it is out to sea, best bet for snow will be over Cape Cod Bay or Cape Cod depending upon the location of strongest wind core and direction of the wind flow from 850mb to the surface. Let's pray for Cape Codders to get their snowfall in this pattern from OES, I think OES events are the coolest. Especially on radar. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Cloud streets are forming over the Cape Cod Bay and north of Provincetown MA extending southward over the Outer Cape including Harwich, Chatham, Brewster, Orleans, Wellfleet, Truro and Provincetown. These locations could see OES flurries or snow showers this morning as one ventures out around 8am. Short range models favor at least snow shower activity over the Cape this morning as rush of 850mb temps of -12C reach this region within northerly wind environment. However the potentially biggest event of the last 15-20 years is possible day 7, I know it is too far out for definitive, so I will try to keep my excitement down as the 00z EURO has turned the winds northwesterly instead of northerly the 12z EURO had yesterday. I can't wait for the short range NAM to get a whiff of this event. 00z GFS was still bullish on the event. So let's discuss these two events please, it is important for Cape Codders to know what is coming down the chute. Link to comment Share on other sites More sharing options...
nzucker Posted December 28, 2015 Share Posted December 28, 2015 How can you forecast a 20-yr OES event 7 days out? That's an eternity on computer models. Like I posted on the storm thread, 7 days ago it looked like the coming SW flow event would be huge warning snows from BGM-ORH-BOS...Now, those areas are barely going to get 1-3", maybe not even that. OES is a very mesoscale phenomenon involving delta Ts (difference between water temperature and air temperature), temps at 850mb and higher for flake production, and wind direction. Since Cape Cod is small, it takes a very particular fetch to generate OES, and a N-NNE fetch is not a favored wind direction, making this a rare event. That's why it would be folly to say "biggest OES in 20 years" so far out. As you say, EC has NW flow so no go. It looks like we get a cold front from N Stream activity rather than a big high or PV feature, so more likely winds are WNW. Also, it's not close to NAM range and NAM sucks. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 I said, it could be as high as a 20 year event, or it could be nothing as the EURO has NW flow. I mention this is a mesoscale event, but I want to talk about the event possibility now, because this is when the discussion counts. Models will change as features move around about the region, if that shortwave becomes more pronounced in the coming days it will back the flow towards more northerly and nnerly instead of westerly. Right now models are at day 7 and GFS forecasts -16C 850mb temps with 8.5 to 9.5C SSTs equates to 24-26C delta ts, which is higher than the expected 22C for extreme instability, GFS already shows convective precip for this time frame at day 7, while this is a day seven, models were more in line at 12z December 27th than 00z December 28th. Still a while to go. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Plus while the models were at day 7 for the LES event expected to hit the Tug Hill Plateau on New Year's Eve and Day the models showed as much precip output as they are showing now for CHH at day 6.5 to 7 Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 nzucker, did I not post both ends of the possible spectrum? I mentioned that this could be a 20 year event, or it could be just like the EURO showed and miss the Cape all together and favor the fishes underneath 2"/hour rates and thundersnow. That is purely the physics of the potential event with delta ts near 24-26C that is insane. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Low level clouds are increasing in coverage this morning and getting more vertical. Also winds out of the north converging with winds out of the northwest over Boston. This could be interesting as 850mb temps cool. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 6z GFS maintains a strong OES event day 6-7. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 28, 2015 Share Posted December 28, 2015 Cape cod isn't really a good OES place. Best place Is usually climo spots from near me to about PYM. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Majority of OES that falls on the 4th is after the 12z period, coolwx.com soundings only goes to 6z on the fourth, got to wait until the 00z tonight to see if how much really falls on the fourth of January. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Scott, what if we get a good long fetch of northerly winds, Cape Cod is a prime spot with NNW to NNE winds. Link to comment Share on other sites More sharing options...
CoastalWx Posted December 28, 2015 Share Posted December 28, 2015 Scott, what if we get a good long fetch of northerly winds, Cape Cod is a prime spot with NNW to NNE winds. The problem is that those setups don't happen often and are transient. You may squeeze an inch or two out of them, but that's it. The only setup that could work would be a NORLUN trough. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 The norlun trough looks to make a comeback on the 6z GFS for the fourth of January. I will be more interested in the 12z and 00z runs later today. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 GFS also a step closer to a coastal snowstorm from Jerry to Ray points south and maybe as far west as Steve. Link to comment Share on other sites More sharing options...
JC-CT Posted December 28, 2015 Share Posted December 28, 2015 How does the extrapolated NAM look for the CHH OES threat? Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 The fact that it has some semblance of an event is good news for CHH. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 I'm interested in the models for day 6-8 and see if the GFS is sniffing out a potential coastal storm, or a norlun trough event or an actual OES event. Very fascinating times ahead for us this winter. Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 Ray you busy from Thursday through Saturday this week? Please so no please say no? LOL, if you are that is fine, but I need to go with someone to take video of that significant Lake Effect Snow event across the Tug Hill Plateau? Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 28, 2015 Share Posted December 28, 2015 Ray you busy from Thursday through Saturday this week? Please so no please say no? LOL, if you are that is fine, but I need to go with someone to take video of that significant Lake Effect Snow event across the Tug Hill Plateau? Well, its New Years......how much are they expecting? Link to comment Share on other sites More sharing options...
USCAPEWEATHERAF Posted December 28, 2015 Author Share Posted December 28, 2015 No accumulations yet forecasted, but 24"+ is my guess. Link to comment Share on other sites More sharing options...
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