vortex95

I wanted to follow up on a post I did last night. Some details here that may not be so apparent to all, and this evolving pattern provides a good example how it's not "one-size-fits-all" for a given pattern and sensible wx. The details count and help quantify a fcst better. In this case, it will not be the same as the pattern we had last week w/ the snow in the Northern Rockies and big heat in the East, despite a strong 500 ridge fcst. I attached a GIF loop of the GFS 500H/V for the next 10 days. You can see the ridge axis/center that forms so far N, you actually get tropical-type easterlies across the srn half of the CONUS and westward moving disturbances. Not tropical waves per se, just weak 500 lows. The first shows up over KS/MO/OK at 96 hr and then moves W under the ridge to the Central Rockies where it merges w/ a vort center that is stuck within the ridge, and then it all ends up moving N and then E around the top of the ridge. And then look at about 156 hr on the SC/GA coast, a small 500 low develops moves W and eventually ends up over srn NM. In this case, despite the 600 dm ridge, this is not classic big heat pattern for the CONUS. It's tropical and unstable w/ easterlies across the srn 1/2 of the CONUS and in the Rockies, despite ridging aloft, weak disturbances are embedded w/ a lot of mid-level RH present. So this means considerable amounts of diurnal RW/TRW, which keeps temps from getting really hot, and is why the 850 temps avg slightly below normal across the srn 1/2 of the CONUS (150 hr ECM 850 anomalies attached) Also, and I failed to mention this yesterday, yes, it is large and strong ridge, but also a *broad* W to E ridge and wavelengths are not sharp, unlike what happened last week. Not all ridges of high pressure are alike, but some act like that. Seriously, one well-known TV met actually has said, "two heat domes will merge and become one large one next week." As if that means anything as to more extreme temps? That's not how it works for high pressure. This person is trying to force the notion that when two low pressure merge (like a ET low and TC), it works the same for high pressure, and thus an end product more intense. Vapid and linear thinking, preying on public ignorance. Ppl just making things up now for hype! The "two heat domes" that will "merge" mentioned above. If you look at the 500 over the CONUS now, they are typical subtropical 500 highs you would find in mid-summer, one over the Desert SW and another one near the Bahamas. So every ridge of high pressure that has climo hot wx is a heat dome now pushed as unusual? And these two subtropical highs, look at the 500 evolution, there is no sign of any "merging" here. I know I have said stuff along these lines before, but I wanted to share another example of how statements on wx just keep devolving more into slop, and at the same time, point out for the ppl on the forum here some of the finer points of a ridge pattern in this case that from a bird's eye view, it many looks the same, but upon closer look, there are important differences that make for different sensible wx.

EMLs are tricky. They are most prevalent and strongest when the atmosphere is very warm ("warm" being relative to the time of year). This mean things are often capped. So despite tons of CAPE and shear, no storms will develop. But if you storms to fire, then you have a primed environment for svr storms. Weak EMLs are often present, w/ mid-level lapse rates 6.5-7.0 C/km, in many tstm days here. However, you want to see at least 7.0 C/km solid for noticeable results or differences. And just a 0.5 C/km difference is huge b/c the range is small. The dry adiabatic lapse rate is 9.8 C/km and the moist adiabatic lapse rate varies depending on temp and moisture, but in the warm season, anything under 6.0 C/km is not good (it does not mean you can't get big storms though). Generally, look for greater than 7.0 C/km at mid-levels in a fairy thick layer on an observed or fcst model sounding. On the models for mid-level lapse rates, they use 700-500 mb. However, that can be misleading. You may have at 150 mb thick EML between those two levels, or say from 750-550 mb, and this qualifies. EMLs do a couple of things that lead to better storms. 1) EMLs promote elevated CAPE, and this CAPE exists independent of diurnal effects, so loss of daytime heating is not as much a factor. And during the day before the convective temp is reached, you already have CAPE aloft just waiting to be tapped, and links w/ building sfc-based CAPE. In the end, you get considerably stronger updrafts in CBs. 2) Where an EML exists is often the best hail growth zone in a CB, so hail at the sfc and/or larger hail is more likely (steep lapse rates and higher mid-level CAPE mean more vigorous updrafts at mid-levels). 3) And along the same lines as above, the EML can be in or close to the mixed phase layer of the CB where charge separation occurs the most, so that means more LTG, esp. in-cloud LTG. Solid EMLs on the East Coast are not common, at least those that occur in sync w/ proper low-level moisture and dynamics/forcing to result in significant svr wx events. Two of the biggest ideal EML events are June 23, 1944 Mid-Atlantic tornado outbreak and the June 8-9, 1953 Great Lakes-New England tornado outbreaks. Another one was July 10, 1989, which is the record for most tornadoes in a single day in New England. That day I experienced first-hand, and that’s when I took note of the EML factor. IAD sounding 00z on the 11th had a distinct EML present. However S of NYC, not storms occurred b/c it was capped. So for the Mid-Atlantic and Northeast's biggest tornado events, typically a solid EML is present, but everything else has to line up almost perfectly for an actual high-end event. In general, having an EML present is a good thing if you want more intense tstms and more overnight storms. I really like what I see coming up for the CONUS 500 pattern. Big hot ridge to our W and we are in persistent WNW or NW flow aloft. This is how you advect a solid EML from the Plains to the East Coast, and WNW or NW flow historically had led some of the biggest svr wx outbreaks in the summer months for the Mid-Atlantic and Northeast.

Sounds like damage control in link title --"not nearly the rainfall we need." Ok, who ever said it would be enough? The point is we got a solid widespread rain event. You have to start somewhere to come out of drought conditions. Geez, wx does not work in nice, neat, even increments and balances out 1-1 when talking short periods of time. A case of you can look at the glass half-full or empty (yes, the pun is there but not intentional!).

Sorry, I couldn't resist!

What happened to your warm front *absolutely* needed for the big R+ in a summer month? Nor'easter is still a nor'easter in July. Only difference is that they are weaker and smaller, but much higher PWATs tend to compensate to give solid QPF. The OER was neat to see today streaming in from the due E!

Even if it was 4-8" widespread, it still would not have been that bad overall b/c it was going to be spread out and most importantly, very dry antecedent conditions overall across SNE! So much of the MSM and hype masters have no clue, or do know, but ignore b/c deflates hype. They think "one-size-fits-all" and the one size is always means the worst. That's now how the wx works and we can do much better now due to improved modeling and understanding of the wx. There is no effort to quantify or scale wx events anyone -- again, it's always "the worst." So you see my overall critical position on how wx is treated in general is not w/o merit. This rain was very beneficial and we needed it, but that is good news and doesn't sell.

Yes, you could clearly see two level of pcpn on radar, low and high, moving in different directions and overlapping, which likely lead to the dense small drops (super "sheet" drizzle?). Almost like warm process rain but w/ more baroclinicity.

Nice li'l tight/coherent wrap up. Models showed this well. Don't always need a deep sfc coastal low for "fun 'n games!"

Can you imagine the consternation alone if this was a fcst snowstorm? 24 hr ago, DXR would have had 2 ft and PVD a foot, and a dusting at BOS. CoastalWx would be like, "HOW CAN THIS BE????!!!!" and basically ready to call it quits, and then the big backlash comes in and saves the day! Reminds a bit of the Bliz of 96 in ern MA. Got about 5" in Woburn w/ an initial burst in the evening, then MEH for the next 8 hr (2SM -SN and I got about 2"). Then the "backlash" came in and I got another 8". So a great storm total (for 1996), but it was piecemeal. Not a smooth event! Also, one of the storms in the Jan-Feb 2015 blitz. SNE got a burst of S+ in the evening, and then it completely stopped, and BKN conditions w/ stars visible along the S Coast. This mesoscale thing w/ a arc of snow moved into srn NH, then drifted back S after midnight, and then incredible development w/ super TS++ predawn into later that morning. Rumor has it CoastalWx passed out a few times due to his ecstasy! Again, not a smooth event, but it all worked out in the end!

First warm blob, now cold blob, next it will be NEUTRAL blob, and they will find an issue/problem w/ it!

Dvorak CI is back up to 7.0 which is 140 kt, after being down 5.5 last night. 7.0 would normally assign 140 kt, but since the eye is so large and a bit ragged, JTWC went w/ 130 kt, which is reasonable. The eye pressure may be as low now as it was when Bavi peaked at 155 kt, however, tightness of the inner core and eye size are paramount. After a couple of ERCs, the overall size of the storm expands and inner core tightness is less (overall power of the storm is basically the same, just spread out more). Also, a slow gain in latitude is increasing Coriolis, and this results in a gradual decrease in tangential winds speeds over time. It's one reason why you rarely see pinhole eyes N of 30N. Eye size is challenge, It depends on if you use IR or VIS, and within IR, what color table you use! Attached is Bavi's eye currently using EIR, BDIR (Dvorak), and VIS. I get 55 nm, 40 nm, and 30 nm for a diameter, respectively! Notice the difference between EIR and BDIR, The BDIR shows the stadium bowl eye structure better than the EIR.

For all intents and purposes, this is the truth. Concerning hot wx, it wasn't so long ago when it was 90+ in New England, they would just say, "a great beach day or BBQ evening!" Now, "stay indoors and cower in fear b/c it is so dangerous outside!" You see how inane that is from just a daily living POV. Yes, you take precautions, but don't let it ruin your day/plans -- or LIFE! Being put in a constant state of fear/alert, that's not "living," that's "existing!" Don't get me wrong, I don't like harping about all this and want to avoid the negative, but at the same time, I feel for the public and up and coming mets and wx enthusiasts that either have no context/perspective or just can't figure out what is what, or who is keeping it real, and who is just off the rails hype, and everyone/everything in between! I know how I would feel if I was a newb and up and coming these days. For those of us that have been around for awhile, we've all been there! Most of the public just wants the basic what, when, and where for wx, at least in real time and for practical daily use. The how and why are secondary or irrelevant! And ppl I speak to that are not mets, most really appreciate the based and straightforward fcst and wx reasoning. And they like to learn about why this or why that b/c they all have seen many forms of of wx, and when the big stuff happens and makes a huge impression on them, they wonder, "what the heck caused that!?" And they all have big storm memories like weenies, it is just more latent/passive, but when you bring an event up, the interest surfaces quickly! Now for mets and wx enthusiasts, we of course want to know the how and why as well, and that's a good thing. But the challenge is for many is just plain information overload and sorting it all out. There is lot of good, solid, and accurate info out there, but also a lot of nonsense and crap. It's funny back in the day (pre-Internet), wx info, esp. for a weenie, was not easy to come by. You had the local news and your wx radio, and then TWC by 1982. And then *any* wx book/magazine you could find at the bookstore or the library (there were not that many, at least compared to the 90s and later)! And the occasional TV special on wx (NOVA on PBS was really good for this). That was about it! Now, it's the other extreme. TMI and not enough time. One can actually get stressed out trying to follow and keep up just for all the models alone we have now (CoastalWx?, WxWiz? LOL)! And then you have social media and mobile devices. Sometimes now, I actually *welcome* a quiet period for wx so I can catch up w/ other things!

If we can get a solid EML (elevated mixed layer) to advect in from the Plains/Midwest, things could be really potent. Big hot ridges to our W w/ WNW or NW flow aloft here is about the only way this can be done. One thing w/ EMLs is that overnight tstms are much more common and more intense. Diurnal heating means little w/ you have lots of elevated CAPE. It's why there are so many overnight intense MCSs in the Plains/Midwest, and the LTG displays are incredible. Not necessarily more CC or CG bolts, but the IC flickering is often amazing, esp. in the mid and upper parts of the CBs.

Or getting "only" 18" of "white rain" in Weymouth instead of the 24" fcst?!

RAOBs (wx balloons) missing is a weak argument these days. Ppl need to get out of the legacy mindsets and get w/ the times. RAOBs are not as super critical as they once where. You have so many other sounding-type data available now, both in situ and remote, like ACARS data from aircraft and NUCAPS soundings several times a day over the CONUS alone from the VIIRS polar orbiters. And we have GOES imagery that updates for the CONUS every 5 min and 4 mesoscale sectors that update every min. Also, a full disk sector every 10 min. Prior to 2016, it was only every 15 min for the CONUS and only once every 3 hr for a full disk. The sampling of the atmosphere over the CONUS and the GOES footprint is way higher now than 10 years ago, both in spatial and temporal restitution! When the next generation GOES-E and W satellites went into operation in 2016 and 2017, respectively, the number of GOES channels went from 5 to 16. It all goes well beyond the basic IR, VIS, and WV channels now to get a significantly better picture of the atmosphere. 85% of all model data globally comes from various types of polar orbiter satellites, and they measure/sample a lot more than just clouds. And those "missing" RAOBs site you see at 12z, almost all of them are taken at 18z instead. Yes, not ideal, but we do run 18z models now, so they are not going to "waste." Who's to say 18z model runs for the CONUS are not somewhat better now at the expense of the 12z? It may be a wash or so little difference, it does not matter. I am not saying RAOBs are not still valuable, they are, but some ppl can't resist drama, stirring the pot, and complaining for clicks/like/attention, among other things, these days and sometimes are disingenuous, as in knowing what I said above about other sources than RAOBs, but leaving it out for "engagement/rage bait."

For all the hype talk about the big ridging and heat for the CONUS coming up central and west, looking at the anomalies fcst, esp. at 850, it isn't nearly as impressive as you would think for a large 600 dm high center spread out over the country. Take a look at the 00z ECMWF at 162 hr 500/850 when the 600 dm center is most prominent (attached). Big heat is limited to the northern tier, and just MEH central and south. What is happening in this case, the ridge center and axis is so far N, you actually get very weak troughing and a rather moist tropical-type air mass over much of the southern half of the country (see 700 RH fcst attached). Pattern for us looks quite good for svr. "Over the top" ridge EML should be fed nicely into the NEUS.

Yah but the 00z ECMWF shows Weymouth still getting 4"!!! LOL.

Well, I should have checked through *all* latest models. The 00z RRFS does this, and the 00z ECMWF this. So partially salvage it? The sfc low is just off the S NJ coast now, and has yet to start to wrap up, and it passes about 80 mi SE of ACK. The solid ENE sfc gradient (for July) is still coming, so I guess what the RRFS and ECMWF are showing could happen?

"Diamond dust" rain???

This is one of the worst short-range busts for rainfall I have seen. You go back a few days, and all global models has solid 1-3" at least up to the MA Pike and 3-6" widespread S of that! And then the difference between the 06/06z and 12z HRRR. Oooo, the HRRR brings it back N big time and the 3/12km NAM stay the course from 06z And now? W-T-...? KBED not even a drop yet. Virga storm! I know the event is not over yet, but too little too late it seems. Only swrn/srn CT verified well. Good thing this isn't winter, otherwise we'd have to drag this classic GIF out!! CoastalWx should post the same GIF but w/ the faces of ppl on the forum included (does he still have that GIF saved?).

Mean trough position in the E UFN. So solid big WxWiz weenie tstm chances are there!

Looks like we stay in semi-active to active period for the region UFN. Showers and tstms every day in some form in at least parts of region thru Sat and maybe Sun. GFS and ECMWF are a lot different for Sun. The GFS has a much stronger trough at 500 and actually develops a small nor'easter offshore. ECMWF nothing at all. The GFS solution suggests a lot of rain. Svr risk for the region highly dependent on where the sfc low tracks. Longer-range, it appears the mean trough position will remain in place in the E, so should be decent chances for some sig tstm events. Last July was quite good, but ugh, next to nothing in Aug, and quite cool much of the time. Actually had some cold air damning a few times IIRC!

Good info. In weak flow when there is lots of storms firing and chaotic, the sheer number of mesoscale factors going at once inevitably leads to a very local environment that can support a supercell for a short time. FL this time of year, all those storms that fire daily, those isolated wind or tornado events you see, are due to the numerous storm interactions. But it's impossible to fcst this b/c such small-scale factors can not be accounted for in the models. It's so conditional and variable! In certain cases, you can get an intense tornado in wind profile that doesn't look conducive at all. This occurs most often when you have huge amounts of CAPE (5000+) and a weak front or boundary present. A storm can fire and if it deviates a lot (more than 90 deg) from the environmental wind flow by virtue of back-building along the front/boundary, it can become a strong supercell. So even though the environmental helicity is low, the storm-relative helicity is large, and an intense tornado can result. The two most striking examples of this was the Plainfield IL Aug 28, 1990 and Jarrell TX May 27, 1997 events. Both devastating F5s and the storms deviated a very hard right w/ CAPE ~7000 present.