csnavywx

Feeling better about this Friday. Not quite there yet, but it's trending towards being a southern slider. Plenty of cold air around and if it comes in more amped/better timed, we cash in. If not, it's out to sea. But regardless, we don't end up with a slopfest or cold rain. All guidance trended better on the 00z. Another day of that and we'll be inside the D4 window and I'd be ready to get excited.

The general evolution towards a slider is great news. Certainly better than the enormous cutter with a wrapped WCB we were stuck with this time.

Flipped to sleet and then a bit of freezing rain about 40m ago now flipping to rain. Had about 90m of decent light-moderate snow. A bit more than I was expecting, but otherwise on track. Mix line blasting north pretty quick.

If it looks like that on the GFS w/ a lower vertical resolution-- I can almost guarantee it's already sleeting. 60+ knots in the warm layer. Once the diabatic cooling potential is gone from evaporation, that mix line is going to *fly* through.

Yep, and goes negative too fast. We want a pitch that comes in farther east. This ain't it. Take the pennies you get and cut your losses on this one.

Name one system where that warm nose was over-forecast on something wrapped up like this. I think this is going to be a bigger sleetfest than most are willing to accept atm. I'd be kind of surprised if DC gets any more than ~3-4 hours of snow out of it before pingers mix in. That elevated warm nose/WCB is going to kill totals east of the mountains.

I'd definitely take that. One theme has been intense banding showing up. But ofc, if there's intense mesoscale lift, there will be mesoscale subsidence nearby.

- Ground temps are warm. - Boundary layer starts warm. - Heaviest amounts are likely to be in intense mesoscale bands. Great if you're in it, but that means somebody is getting shafted with subsidence. - SLRs will be very low to start. They improve as time goes on, but we're looking at an 7-9:1 maybe improving to 10:1 by the end. - Sneaky southerly flow at ~700mb might be just warm enough to mix sleet on the southern end as the closed low opens up. - Track very sensitive to small changes. Luckily we're inside 24 hours, so only minor shifts are likely going forward. + Perfect track. Southern slider off Hatteras-east of ORF with a closed (!) low that doesn't track up the coast. + Related to first, but no significant WAA belt to mix (except perhaps very high up >700mb). Column temps cool through the storm. + Very high moisture availability. 1"+ QPF/6 hours. Incidentally, while models tend to overdo QPF <0.75"/6 hr, the opposite is true for values bigger than that. + DGZ and max lift overlap for a good while. Combined with near iso-thermal layer (-2 to -8c) below, this will probably result in a ton of big rimed dendritic and mixed aggregates. Fat flakes that can pile up fast. + Near min sun angle and high boundary layer winds will limit the effect of the Bay. Still expect shoreline accumulation to be lower, but not as bad as with low-gradient situations. + Low static stability, moist neutral to even slightly unstable (wrt theta-e) in mid-levels favors some convectively-enhanced mesoscale banding. Good deformation zone too. Bands will be intense, which is good, because we need high rates to overcome thermal issues initially. Right now, thinking max band runs from Mechanicsville to Easton/Cambridge. 6-12" of wet concrete.

Busting out BUFKIT on this morning's guidance has been eye-opening. More to come in a bit....

Thank you for your sacrifice, sir. We will relish every flake.

The eyewitness accounts from Larsen A when it disintegrated were pretty eye opening. It went fast, as did B. C is looking a bit less healthy nowadays. As for Thwaites, losing that shelf in the next decade would set up some pretty bad news for mid-century. There's not much to keep that mass from moving at an increasingly faster clip once the plug is degraded.

Rolling it forward to Jan/Feb is "weenie suicide" territory. Your meme game is gonna have to be sharp.

Happy for those seeing flakes or pellets today. Enjoy it, because big ooof:

Blizz posts are usually a good, contrarian indicator and a solid sign we've hit bottom on a short-term trend.

If you believe the CFS weeklies and NMME monthlies, there's a lot more where that came from. Very little snowcover build over NA this month and our source region for cold air remains quite warm, so even the cooldowns will be more of a reversion closer to the mean rather than any significant negative departures.

It's just you. Plenty of banding still around 80% of the core. Annulars generally require marginal SSTs and light east-southeast shear to offset beta shear. That helps strip banding and forces the vortex upright.

Top-heavy nature of the CAPE tomorrow and low-level capping means updrafts might initially struggle in a relatively anemic cumulus field, but once the cap weakens sufficiently, it should take off pretty quickly. Little warm-sector cloudiness to speak of (other than a bit of acu or accas). Abnormally large proportion of the instability is above the freezing level (for these parts). Coming up with 0.5-0.75" on the hail forecasting diagram, though could easily breach 1" with some assist from mid-level rotation in individual cells. Gusts likely to be 35-45kt widespread, especially if a small LEWP or two gets started. Lightning might end up being some of the best and most intense of the season for some areas, especially closer to the Bay.

No, annular hurricanes generally require marginal SSTs and light southeasterly shear. Sam has neither nor is expected to have either.

Wow, that's pretty gnarly then. Wasn't immediately obvious that it was going to be quite that bad up there -- but the radar structure on landfall was still pretty tropical in appearance with a partially intact eyewall.

How was it up there -- as compared to say a strong mid-winter cyclone?

After looking at the METAR list, it sure looks like it.

I see the MSY wind sensor got knocked out. Ugh, not great.

Starting to get real in NOLA: METAR: KMSY 292240Z AUTO 09054G72KT 1/4SM +RA OVC012 25/ A2905 RMK AO2 PK WND 08076/2208 LTG DSNT S PRESFR P0023 T0250 RVRNO $

The breakdown of the vortex rossby waves in the eyewall over the past 30 minutes is like something out of a textbook. Also waves propagating out from the center into the rainbands (obvious from radar loop).

Yeah, I was premature on the bank call. Either wobbling or getting some frictional torqueing as it interacts with the coastal interface -- but whatever it is, we'll take it.