Quincy

12z 3km NAM has very good verification with Oklahoma dew points, as moisture is over performing many progs. On the other hand, most models (NAM included) show cloud cover, midday/afternoon precip and limited instability across central Oklahoma on Monday. One area to watch may be western Kansas, as some CAMs try to initiate isolated storms around 23-00z. I think it was two or three years ago where an early season event looked like a CAP bust, except an isolated storm blew up and went nuts over western Kansas. The timing of everything seems to be slightly late for widespread CI, but if moisture is over performing and more CAMs are coming onboard with isolated convection, watch out. Monday is quite a complex setup with many different areas to watch. I’m not really concerned about Oklahoma (prior to 01-02z), but aside from isolated dryline storm potential in western Kansas… storms also appear likely near the warm front in Nebraska, while some guidance suggests CIN may erode enough for storms farther SE into northeastern Kansas. West/NW Texas could see afternoon storms, although the parameter space seems disjointed enough to suggest mixed/messy storm modes there. Hell, you could even see a storm near the triple point in the Nebraska panhandle or just downwind of the Black Hills. More widespread convection appears plausible after dark across Kansas and surrounding areas. It feels like an event that will probably see wide gaps in storm coverage. To a point where swaths of the ENH risk may see nothing at all, while an isolated storm or two could be prolific. It’s still a wait and see type of setup, so I won’t try to nail down any specifics. Confidence is lower than usual given the synoptic pattern. I remain pessimistic, but not as much as say 24 hours ago.

I’ve mostly stayed quiet on Monday because the models keep shifting. Just looking at the last few runs of the 3km NAM, now that it’s in range… the warm sector ahead of the dryline keeps narrowing, to a point now that the 48hr prog for 00z Tuesday looks bleak for pre-sunset convective initiation prospects. At this point, daytime initiation in Nebraska seems more plausible than OK/TX, closer to the surface low. Tuesday is also getting more intriguing, particularly around the lower Missouri Valley vicinity, but maybe around Arkansas too. The slower progression of the system seems to suggest Tuesday *might* be the main show. If trends have taught us anything, it’s that nothing is set in stone, especially several days out. Things may continue to change. By the way, last check for Monday is that 4/26/14 showed up as a top analog. That event featured isolated severe storms going up around 01-02z in far northwest Texas. The next day… that featured isolated intense (tornadic) supercells in Arkansas, as well as severe storms north into Missouri and Iowa. Take analogs with a grain of salt, because 4/14/12 was showing up for a while with Monday.

Interesting, yes, but I’m not on board with a high-end event yet. Still early in the season, so smaller scale variables could still throw a wrench in it. Models are waffling on timing and while it doesn’t look perfect, I don’t see any harm in starting a discussion this far out. Analog guidance suggests a Day 6 30% contour is warranted. In fact, just looking at the medium range models, this could be a multi day threat that also includes Tuesday and/or Wednesday.

Pretty meh so far across the Oklahoma/Ozarks portion of the threat some. Messy storm modes and somewhat veered low level winds. It will be interesting to see if anything goes up near the Red River later as the low-level jet increases. Otherwise the near-term tornado threat in Oklahoma is quite low.

12z soundings show an unseasonably unstable air mass already in place (for early day, mid-March standards) with some capping. However, guidance erodes capping quite quickly with some model solutions initiating storms prior to midday. Wind profiles aren’t ideal, but should be sufficient for initial supercells. Given the background environment, you could see a few intense supercells form. I’d expect complex storm modes/interactions with time, but if a storm can thread the needle, significant severe is certainly a possibility.

Kansas and Missouri are the areas to watch late this afternoon into this evening. A tornado threat could develop near I-70 along the warm front, but we’ll have to see how narrow the warm sector is and if storms outrun the front. Right now, dew points are confined to the 40s across much of Kansas, but lower 60s dews have surged into northeastern Oklahoma. At one point there was some concern about convective initiation near the dryline in Oklahoma. That seems unlikely at this point. A non-zero shot, as a few outlier models (6z RGEM) still try to convect there. Very shallow moisture will likely preclude any development. Even if something were to initiate, it would likely be short lived. Tomorrow looks interesting over a larger area with a broad warm sector anticipated. Evolution of overnight storms into early tomorrow morning will be a factor to watch. Stay tuned.

Not common for an essentially straight north from Bermuda with no recurve. As modeled, it even bended back NNW a bit. It’s a good thing it wasn’t a 200 miles west or it would have been a much higher impact event for the I-95 corridor.

Wow. No kidding. PWs mostly below an inch, outside of the Cape/isIands. That’ll do it.

Did Kev write this headline? https://grist.org/extreme-weather/its-gigantic-hurricane-lee-heads-for-new-england-and-atlantic-canada/

A nudge west, but still avoids US landfall. Curves right up into Fundy.

12z 3km NAM shows several hours with gusts over 60 mph on the outer Cape. Probably a bit overdone, but wouldn’t be surprised to see a few obs with gusts over 50 mph.

Even the SREF is east. Maybe it ends up being a dry weekend for TOL with just an occasional light breeze?

The outliers are shifting east and there’s more support for a wide right turn, than a rogue landfall left. I’d stick near the mean. Of course it could waffle a little either way, but there’s a higher probability for this to hit NS than for the Cape to see landfall. SREFs are going the same way. A few kept showing a left hook into SNE. Now those have tightened up to the east.

A tighter look at the 18z GEFS at 78 hours shows about half of the members east of the mean. Those to the west are relatively tight. Only about three members bring the center close to Cape Cod. None show a landfall there.

That’s what I mean. The totality of the runs over the past few days did not show a landfall. Kudos to NHC for not waffling and sticking closer to the consensus with continuity. Live and die by the model runs. Another great example that ensemble means can be very helpful when there’s uncertainty.

Granted the track with Lee is unique, we’ve seen this same thing play out almost every year. A tropical system threatens the East Coast. It’s not unprecedented for landfall, but it’s relatively uncommon in most cases. Model noise shows a few runs that either make or threaten landfall and people start freaking out. I did play into the hype a bit, but it’s time to accept that any substantial westward trend is done What percentage of the model runs/ensemble members showed a New England landfall over the past 3-4 days? 10%? 20%? 5%? I still think there’s a legit possibility that the Cape and parts of coastal Maine are affected with tropical storm force conditions and some flooding, but anyone hoping for a repeat of Bob, Gloria or Sandy are going to be disappointed.

GEFS is way SW from 06z, but a tick east of 00z. Solutions are consolidating and intensity has notched up slightly. (Mainly due to less spread dampening the mean)

GFS ever so slightly east. The wind field is still fairly intact. One of the stronger runs. Verbatim, looks like a cat 1 cane just SE of Maine, if the run is taken literally. There’s a little tease jog NW between 72-78hr before it makes the NNE turn into the Bay of Fundy.

You actually want slower movement now, so there’s less interaction with the initial exiting shortwave. Less opportunity to get tugged east. The models seek to be locking in. There’s some noise, but I don’t think there’s room for any major shifts west or east now that we’re getting inside of 72ish hours.

Keep in mind, this thing is going to bend back N and possibly even NNE for a time around the Atlantic ridge, before a likely shift back N/NNW. Not seeing any interaction with an approaching shortwave across the Upper Midwest/Great Lakes. That will be key if there are any hopes left for a westward turn. I imagine it won’t go much more west than the current consensus, but you never know.

Through 72 hours, it’s basically between 00z and 06z runs. Heading for Bar Harbor it looks like.

No big changes, almost identical to the 00z run thru 57hr

Even an east tick is going to still ugly for coastal eastern Mass. Especially Beverly toward Cape Cod Bay. N/NE fetch, gusts easily reaching 50-60+. Flooding is a real concern given the wind field size and trajectory.

It’s guidance. Almost all guidance has some utility. You can identify trends, spread and uncertainty. Just keep in mind the usual biases. I’ll grant you all that the SREF should not be the preferred or only guidance you look at with tropical cyclones.

Because I’m bored and I like that it shows the low centers. I mainly use that page for severe. But it’s really not that much different than posting 12km NAM stuff. 3km NAM coming into range soon. That’ll be fun