Jack Sillin

Tis the season... Already had Arthur and Bertha so we're off to a hot start. 92L out in the open Atlantic (https://weather.us/satellite/546-w-263-n/satellite-color-super-hd-15min/20200529-2020z.html) might claim "Cristobal" first but it's no threat to land. Perhaps the first real issue of the season will emerge from the developing Central American Gyre? Some longer musings: https://blog.weather.us/could-we-see-the-third-tropical-cyclone-of-the-2020-season-form-in-the-gulf-of-mexico-next-week/

going.. going... gone was always gonna be tricky but I'm running out of plausible paths to an interesting event SW of Nova Scotia. #WagonsNortheast

Looking for hope that the weekend storm ends up a hit? ECMWF gets us within a rounding error on the lead s/w timing but the GFS offers no such opportunity. Why do I think the ECMWF has a better handle on things? Let's take a trip to Hawaii Thunderstorms. Thursday evening. ECMWF prob better than GFS' efforts to parameterize. Known bias Diabatic enhancement of jet streak. Thursday evening. Sends our secondary s/w digging instead of sliding. and voila, if you can get that lead s/w tucked back into NC/SC you should be in business (ECMWF left panel). We really think that's impossible given its vacation to N Mexico midweek? Wouldn't totally rule it out. Anyways, for those wanting more of my rambling, I updated the blog around 6:30 https://blog.weather.us/an-updated-look-at-the-prospects-for-an-east-coast-storm-this-weekend/

00z ecmwf a lot closer to a hit than most prob think IMO. Check out how the Pacific jet buckles and now we have strong NW winds over ND as opposed to W winds just a little shortwave timing off from getting a storm (vs making an impossible connection in Zonal flow) prob explains why more EPS members went for the coastal track last night (though while keeping it on the shallower side until it's in the Maritimes)

ICON kept the storm closer to the coast, but it left 80% of the southern stream disturbance behind over the GOM. Picked up enough for >flurries but if you're lookin for the big one, it's gonna be hard to find in this pattern (I talked a lot more about that https://blog.weather.us/forecast-for-weekend-east-coast-storm-remains-uncertain/ for those interested)

Opening salvo from 12z global guidance comes from the ICON (German) model... Certainly looks promising though man are we leaving some energy behind over TX/Mexico. For those interested, I put some longer form thoughts up on the blog this morning: https://blog.weather.us/forecast-for-weekend-east-coast-storm-remains-uncertain/

focus on the west coast, more ridging there would increase the odds of a phase out east

here's a trend in EPS guidance you probably weren't looking for, but is certainly encouraging

ECMWF deterministic is wide right, but seriously check out what happens after it roars into the Gulf of Saint Lawrence. Its diabatic outflow jet is so strong it puts up a giant Greenland block! Moreover, the immense poleward and upward heat fluxes from that type of event may be enough to split the stratospheric PV (in tandem with the building Alaskan ridge Any of the long range specialists feel free to tell me this is bs, but I'm starting to think there may be a big silver lining if this misses

Not a bad signal. Deterministic runs will drag ya on a wild goose chase while ensembles point slowly but steadily towards the eventual outcome

don't remember seeing that in my KU books

12z ECMWF lookin pretty strong with the first disturbance as it moves into WA/OR on Tuesday AM. Curious to see if it's so strong/south it gets left behind over Baja https://weather.us/model-charts/euro/2020012612/1196-w-396-n/relative-vorticity-500mb/20200128-1200z.html

12z GEM takes that NEPAC (faux-N stream) disturbance slow and late into N BC... ...which means it can't catch up in time. Still could get something out of that southern stream wave but you're gonna have a hard time finding cold air. Interesting, seems like we've identified a benchmark of sorts. Need to figure out what's gonna happen with that s/w on Thursday. That's one of the more important puzzles ATTM IMO

spitballing here... I wonder if the rapid zonal flow into BC on Thursday is actually the reason the GFS ends up a hit. Need to get that disturbance from the NEPAC into the Lakes ASAP, which is a lot harder if it has to ride over a ridge. Counterintuitive, but maybe true?

Who else is more interested in the period immediately following the weekend system vs the weekend system itself? That one goes on to anchor around 50/50 while there are some hints of a baby -NAO and possibly even some riding building into AK. Long ways off, but worth keepin a half an eye on particularly since it looks like it's gonna be hard to pull off a big one this weekend