purduewx80

That WaPo article appears to have been incorrect in regards to the GFS "not being tweaked". Aside from any 100% normal changes in forecast skill, there are no obvious issues being caused by the shutdown. There have been some minor issues with NWS offices not receiving shipments of helium/equipment to launch their balloons. OKX was one of those offices that missed a few soundings in the past week. As far as I understand, no data is going missed other than a 1-off RAOB here and there.

Yep - I'd say that's the most well agreed upon part of the forecast. Friday's system helps open up the Gulf for business.

Steady as she goes on the 12Z EPS next weekend w/ 850 temps touching 0; otherwise track of the mean low would be favorable for mostly frozen precip here. May be some boundary layer issues Friday but I think that's worth watching for a few inches, too.

nope. all the ensembles favor a colder storm than the GFS and GEM ops.

Yes, the FV3 is the new version of the GFS; the pivotalwx link is for the current operational version. They are entirely different models.

It literally says 2m temperatures on the top. Ridging from the North Pole to just N of Alaska through the extended period has already and will continue to deliver frigid air into North America. Widespread -30s in place over the NW Territories this morning.

confluence associated with digging northern stream vort doing its thing with the rapid clearing and end to light snow here. snow will expand back to the north this evening once that pushes east but should put on the brakes about 50 miles south of the city.

The RAP is an excellent model but should only be used inside of 12 hours.

Southern stream lagging too. Snowing with sub-zero wind chills in NYC is nothing to sneeze at. That airmass pressing in looks brutal.

the amplitude is not forecast nearly as high as back in december

I'd say a superensemble approach like that is definitely the best right right now.

Yep, was exactly a week ago that the 12Z run showed this weekend's storm as a monster.

yup, going to be big. hope the EPS makes the same changes.

This is simply a more advanced version of Deep Thunder (or MPAS) that has been making the rounds the past year or two. Operational forecasters currently only have access to the 15km version; 3km is not yet available so it's tough to say how well it will perform.

EPS looks a bit better w/ the confluence in the NE Sunday; more QPF on the mean as well.

No kidding; 12Z soundings out in the Lakes/Midwest have 7-8 C/km lapse rates! The 500mb jet max currently poking into the Chicago area will be favorably placed for strong lift around midnight tonight.

Looks like another non-zero risk of thunderstorms in the area overnight. Steep lapse rates with the approaching upper trough will provide some minimal CAPE ahead of its associated cold front. Could mainly be gusty showers for the NYC area 11-2 tonight; lightning appears most likely for the mountains to the W and N.

Close on ECM/EPS too. EPS made some nice changes at 500mb out west...Pacific not crashing the party quite as hard as before w/ more ridging in the Rockies.

convective precip this afternoon is mainly driven by the 500mb jet nosing into areas south of montauk and the islands - both left front quad dynamics and diffluent flow are contributing to lift. thunderstorms really took off out there as a result and robbed the metro area of moisture and the overall best conditions. there is an mcv south of kmtp that is part of the broader low and mid-level circulations. today is a good example of how mesoscale features can steal the show with some of these coastal lows. very few if any models consistently nailed the two-max precip; occurring well nw and se of the city. communicating how important nowcasting is over model-hugging can be a huge part of a meteorologist's job, despite the push to make operational decisions sometimes days in advance. perhaps this is somewhat moot today since it's far too warm for snow. as the pattern becomes more favorable for colder air invading in the medium range and beyond, we should all keep in mind the myriad of reasons why there can be huge differences in snow amounts across the city and northeast in general with nor'easters and other coastal storms.

there's a pretty cool ~850mb feature over northern jersey producing some heavy downpours in the region. with favorable synoptic support in most of the eastern mid-atlantic and southern new england, it now just comes down to the multiple, smaller areas of lift that rotate around the deepening, complex low. i think some of the heavier precip that has yet to develop should focus near the trowal (trough of warm air aloft) this afternoon. most of the hi-res seem to favor areas just s and e of the city for the deeper convection, including parts of the jersey shore and long island.

it very well may be, but it's significant to me that the ensembles have for several runs in a row now shown a colder coastal storm at that point.

N and W with what exactly...the upper trough? The mean takes the low from offshore SC to offshore Novia Scotia. I'd say that's a cold track; in fact, I'd be more concerned with another SE/Mid-Atlantic special with that look than a warm solution. Literally the actual vast majority of ensembles have a cold storm d9 or 10.

totally untrue. if you look at the clustering of canadian, euro and gfs ensembles, the vast majority favor the cold storm.

i think a takeaway from all the guidance today is that there is still a lot of spread in where the QPF max lies. can't wait til it's actually cold enough for snow and we're shoulder shrugging 24 hours in advance.