Ground Scouring

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Everything posted by Ground Scouring

  1. The CanSIPS, NMME, and CFSv2 models are suggesting that the current +PDO, which has persisted for two years, will continue through the fall (and perhaps early winter) of 2016. Such a long +PDO stretch without a single monthly negative reading would be unprecedented since the early 1940s. We've already seen 25 consecutive months of positive values. Is there any climate feedback that could favor more frequent/intense or long-lived +PDO cycles in a warmer world? Obviously, they've occurred many times on (and off) record. http://research.jisao.washington.edu/pdo/PDO.latest
  2. Most likely the warming of the Pacific/Indian basins and the attendant Hadley expansion have been the long-term climatic signals favoring drier conditions in CA. The overuse of local resources is worrisome in light of the overall changes in the global climate system. At some point, conditions and overpopulation could make parts of the state uninhabitable, barring technological evolution, which is always likely to help people cope with change. The question is whether there is some point at which even larger sacrifices besides conservation will need to be made.
  3. Long-range guidance (CanSIPS, NMME, CFSv2, etc.) has been fairly consistent in depicting a 2011-type summertime pattern at 500 mb, with a mean ridge over the southern High Plains and a weakness over the western Atlantic. That type of pattern would be mostly very unfavorable for storms to hit the United States, unless homegrown MCV-type/frontal development were to occur in the northern Gulf of Mexico. Otherwise, storms approaching from the MDR would likely curve out to sea or continue into the Caribbean, where westerly shear may be elevated thanks to the tenacious +PDO (shown by all guidance for ASO '16), with attendant warmer-than-average SST projected off the Pacific Northwest and Baja California. We'll likely have a slightly-above-average season with few, if any, U.S. landfalls. 2011 tracks
  4. Ditto. And I'll be the first to say that my previous (low) expectations for DCA have/are going out the window. What a storm...!
  5. Long-term radar doesn't show the dry slot filling in. The fact that some people are relying on one model showing unrealistic totals shows desperation (though understandably so). DCA, at least, isn't getting more than 5" additional inches out of this storm. The show is all along the Appalachians.
  6. Honestly, by most people's standards this won't end up as historic, simply because the heaviest +SN is out in the boondocks of far northern VA, eastern WV, and western MD. Technically, it's still a HECS, but considering how those areas have seen many similar events, it's not as historic as similar totals would be farther east and south. After all, the areas most affected are along the Appalachians...
  7. Models continue to advertise a potentially significant threat around 30 Jan–1 Feb, with the 12Z deterministic ECMWF and the 12Z EPS showing one of the warmest low-level air masses since 26 Dec 2015 (the date of the Garland, TX, EF4 tornado) over the southern High Plains for multiple days. In fact, even the EPS mean shows 15°C 850-mb temperatures reaching as far north as the TX/OK panhandles on at least two of the days that I mentioned. One important key is the relatively low amplitude of the upcoming pattern, with its lack of significant cold intrusions, which not only may prevent heights from rising too much ahead of any ejecting disturbance, but also allows southwesterly low-level flow to advect richer instability (as well as a noticeable if not strong elevated mixed layer, which is surprising given the subtropical jet) north from the Mexican plateau. The tongue of greatest instability is likely to be at least a bit narrower than projected at this point, but the fact that we are talking about EMLs and a potentially significant southern High Plains threat in a potent El Niño says a lot. For reference:
  8. Both the EPS and the GEFS are signaling a major long-range pattern shift toward the the end of January and the first week of February (especially around 28 Jan–1 Feb), with a restrengthening of the polar vortex and at least a transient +NAO/–EPO/–PNA period taking hold. Even at this range, models are indicating that the polar jet will take over as the dominant stream with strong hints of multiple shortwave impulses intruding into the Pacific Northwest, likely inducing lee cyclogenesis east of the Rockies. Details regarding ejection and overall evolution are obviously too early to ascertain, but the overall trend toward a more zonal look/longer wavelengths favors a Southeast ridge with likely favorable moisture vectors out of the Caribbean, setting up a potentially decent return flow over the southern High Plains for a few days in advance of any potential ejecting disturbance. There aren't many analogs from strong El Niño events since 1950, but an interesting one is 26 Feb 1958, which was somewhat similar synoptic-wise and featured several significant tornadoes across LA and MS. An interesting difference is that this case may also extend the opportunity for severe weather to the southern High Plains.
  9. Total: 1,229 tornadoes First High Risk: February 1 I'll even add that I expect the first High Risk to affect somewhere in the lower MS Valley (most likely centered around NE LA/E AR/central and N MS/SW TN). It will likely be associated with a multi-day outbreak commencing on January 31 over the southern High Plains (N TX/S OK).
  10. This area really needs an extra radar to fill in holes, considering the demographic vulnerabilities of the area and much of FL (mobile homes, densely packed subdivisions and apartments, elderly snowbirds, etc.). We've already seen two fatalities in a mobile home from that "large and extremely dangerous" tornado near Duette in Manatee County. Seven people were in the home when the tornado hit and did not take any precautions whatsoever. There are numerous mobile homes in the Fort Myers/Cape Coral area as well and is a potential disaster waiting to happen, especially with paltry radar coverage.
  11. Do you have any scientific basis for this statement, besides ALEX? 1937-38 and 1954-55 had a completely different ENSO set-up from this winter season's.
  12. Don, I'd kindly wish to correct you. Reanalysis has upgraded ALICE's peak winds in January to 80 kt on 2 January, making ALEX the second strongest. ALEX also happens to be the second most northeasterly hurricane on record in the basin, behind only VINCE in 2005. Best wishes!
  13. From the official NHC site (Special Message). This would likely mark the first coincidence (simultaneous occurrence) of two January tropical cyclones in the Atlantic and Central Pacific, respectively, and definitely marks the first January Atlantic TC since 1978.
  14. Surface analyses by TAFB at 12Z indicate that the surrounding air mass has sufficiently modified so that 90L has practically shed its cold front. The system is more symmetric than previously, there are hints of mid-level anticyclonic flow as the cold-core trough shears out. Satellite imagery shows a steady improvement in organization, with a concentrated area of convection and even a formative eye, though the structure is still a bit tilted overall. The system actually looks to be transitioning straight to tropical status without an intermediate stage, though the switch will only last about a day or so, as the system is already curving northeast and leaving warmer SST (it is already over an area with below-average anomalies thus far). Nevertheless, the system looks to have winds approaching hurricane status at this time (55-60 kt). It seems likely to become a hurricane-strength system shortly. Maybe it will be upgraded in a post-seasonal analysis, making it one of only two Atlantic cyclones to reach hurricane status in January. Amazing...
  15. Compared to 1997-2012, the 2013-15 period shows clear cooling trends in the deep tropics, especially near the Caribbean, along with noted cooling southeast of Greenland and warming off the East Coast/Northeastern U.S. According to Dr. Phil Klotzbach, these trends signal a weakening or reversal of the AMOC/+AMO due in part to solar activity, the NAO, and climate change. The CFSv2 (see Levi Cowan's site for the monthly data) and CanSIPS show the bulk of the warmest anomalies near the Eastern Seaboard with relatively cooler but still positive anomalies in the MDR, though the CFS shows below-average SST in the Caribbean by September. I haven't seen anyone suggesting that the AMO will be favorable this upcoming season, given that it has to recover significantly between now and peak season. Here you can see the influence of the +NAO trend: Note the impact on SST anomalies:
  16. I know that they're both long-range outlooks, but both CanSIPS and the CFSv2 are showing a rather –AMO by peak season (September), with cooler-than-average anomalies in the North Atlantic and the warmest anomalies concentrated along the Eastern Seaboard/off the Northeastern U.S. This is consistent with a weakened AMOC. Of course, there are some major differences, with CanSIPS showing a warmer Caribbean and a cool eastern Pacific with a strong La Niña ongoing, while the CFSv2 is quite the opposite and overall more unfavorable for the Atlantic (–AMO plus enhanced shear via EPAC forcing). The December '15 ECMWF long-range forecast doesn't extend beyond June, but also shows a similar SST configuration in the Atlantic: warmest anomalies off the East Coast, relatively cooler anomalies in the MDR, below-average anomalies in the North Atlantic. So the model consensus seems to be that the AMO won't be particularly favorable this upcoming season. Overall, how much the AMO rebounds from its current low will depend in part on the state of the NAO in JFM. We would need a mean –NAO this month and a strongly negative –NAO in February/March to really allow a substantial weakening of the trades and a big warm-up in the MDR. Down the line, the MJO, the rate of decay of El Niño, and the state of the IOD will also be important, especially if the AMO does not recover. Another thing to keep in mind is that a –AMO correlates with a weakened subtropical high and more development outside the deep tropics, meaning that storms, when available, are much more likely to curve out to sea, which would mean that the U.S. would likely go yet another year without a major (and possibly any hurricane) landfall. If we are indeed in an altered climate regime, then we could go another decade or more without any major U.S. landfalls, given that the current global climate regime is something that we have not observed in modern times. Overall, my sense is that the Atlantic may be dead for the foreseeable future, with the mean activity shifting over into the Pacific, given the rate of SST warming over there and the likelihood for more active MJO periods.
  17. The reference is the book Gladesmen: Gator Hunters, Moonshiners, and Skiffers by Glen Simmons and Laura Ogden (Gainesville: University Press of Florida, 1998). Chapter 4, "Flamingo and the Cape" (pp. 122-163), contains a number of images taken within a few years of the 1935 hurricane's passage over Cape Sable, now within the southwestern part of Everglades National Park on the South Florida mainland. Pages 126, 145, and 157 contain images showing how the 1935 hurricane literally stripped bare and even partly debarked black mangrove forests in the area.
  18. Josh, You've had so many fantastic intercepts recently in the Pacific (both east and west) that I've followed heartily...but don't you wish that some of that activity will filter closer to home? The lack of a major U.S. landfall since 2005 has really added manifold costs to your far-flung chases. Every once in a while, you need a little extra geographical variety. Plus, you've chased a lot of compact, intense cyclones recently...don't you wish for a big but intense major closer to the U.S.? We haven't had a large-sized Category 4/5 landfall in the U.S. since HUGO 1989. On this matter, the standpoints of preparedness and storm chasing converge nicely, for such a long period--more than 26 years--without a sprawling, extremely strong landfall (by maximum sustained winds of ≥113 kt) also gives coastal communities a false sense of security, especially given fading memories of the human mistakes made before, during, and after such storms like KATRINA, a large storm that still degraded significantly prior to landfall. A lot of people thought that existing infrastructure and emergency readiness could handle a storm like KATRINA (and even Cat.-1 winds in WILMA in Southeast FL)...yet we ended up with 1,836 dead, ignored evacuation orders, poor maintenance of infrastructure, and a dismal response on the local, state, and federal levels. South FL, especially its condos, fared surprisingly badly in Cat.-1 WILMA. Given how no one left Key West prior to WILMA, and how many officials in Galveston dismissed IKE, you have to wonder if we are giving ourselves too much credit. We were just lucky that we didn't have worst-case scenarios. Ultimately, going too long without a major hurricane of HUGO-type proportions allows societies to continue to tolerate corrupt politics, poor communications, bad infrastructure, and complacency that put communities at risk. Perhaps we should not assume that, say, a repeat of the 1926 Miami hurricane--a very large, 125-kt/930-mb 'cane (read the Wikipedia article that I expanded)--would not result in hundreds of deaths, even in South FL, especially given the degraded Okeechobee dike. So, if people blame you for eagerly anticipating major landfalls as chase subjects, you should also remind them that hurricanes serve a larger Darwinian purpose in weeding out faulty logic, poor policies, misplaced societal priorities, and the body of people who just won't listen and get out as needed. You actually NEED big storms (and other, more human-made catastrophes) to occur on a rather frequent basis for societies to learn from error, advance, and adapt for the better. Plus, they're essential to scientific analysis that improves our knowledge of tropical cyclones and their dynamics. I'm sorry if I went a bit off topic, but this just reflects my appreciation and admiration for your scientifically invaluable work. Keep it up, and Happy Thanksgiving!
  19. Along with the wind-testing of the anemometer at the Cuixmala biological station, this survey--and your data!--should be very useful in gauging the true strength of PATRICIA at landfall. I'm very gratified to see that this historic event is being (and has been!) documented to the best of everyone's ability. Hopefully, the data will culminate in raw material suited to in-depth studies, aside from that contained in the official, post-seasonal report. I would also love to see Mexico make investments in new radar sites.
  20. The wind damage on Grand Cayman in Ivan, while severe, does not compare to that in the other cases that I listed. Most of the trees stripped bare on the island were deciduous trees that shed leaves readily, such as Australian pines (Casuarina) and Terminalia trees. Many other trees seem to have been uprooted and stripped by storm surge rather than wind. Moreover, I haven't seen coconut palms--a signature tree--stripped bare, unlike in the other storms that I've listed, even though, over the long run, more Category 4/5 cyclones have likely impacted Grand Cayman, given its location, than those that hit the U.S. I've seen images showing numerous coconut palms stripped in Cabo San Lucas after Odile (2014), a storm that officially is 110 kt--high-end Category 3--at landfall in Mexico, though I believe that it should be 115 kt (low-end Category 4) instead.
  21. Is anyone willing to comment on this? I'd be interested in hearing other views.
  22. Maybe this is a separate argument, but I can't think of a single tropical cyclone, globally, that killed more than 50-100 people from wind alone. I have read many sources on the history of tropical cyclones worldwide, and I've yet to find a reliable source indicating such a high death toll solely attributable to intense winds. This is true even for the strongest landfalls such as the 1935 hurricane, Andrew, Charley, Hugo, Janet, Haiyan, Camille, etc. If we were to estimate death tolls by the strength of a storm, then Andrew, based on its damage, should have caused hundreds of deaths. The actual toll in the storm, based on direct deaths, was 15 in the worst-hit areas of South Florida. All evidence that I've seen, including the judgment of former meteorologists, is that the vast majority (likely ≥ 75-80%) of deaths in tropical cyclones have been related to inland flooding or storm surge. All the Category 4/5 landfalls that caused 100+ deaths seem to have done so via storm surge or flooding/mudslides. In Camille, for instance, I don't think that there was a single death attributable to major hurricane winds at any particular location. All the deaths in the U.S. were from storm surge and inland flooding, with a relative handful from falling/uprooted trees (indicative of tropical storm-force or Category 1 winds). As you've said, a collapsed structure is a collapsed structure, and most inhabited areas don't experience the strongest winds in a Category 4/5 cyclone, even one that is rapidly deepening, especially if the system is compact. Given that lightweight or poorly anchored structures disintegrate in even minimal hurricane winds, the practical, wind-based impact from a Category 1/2 would be the same as that of a Category 4/5...at least on frail structures, such as those in the rural fishing villages that Patricia impacted. Yet so far, we have heard of very few direct deaths from Patricia, almost none of them wind-related. My point is that, based on historical experience, my own judgment is that, for certain types of (weak) structures, there is little difference between the impact of a weak storm and a major hurricane...much less between a 130-kt hit and a 145-kt hit. Given that we haven't directly sampled the strongest winds on land in a 130- or 145-kt landfall, we don't have much empirical data with which to compare the wind-based damages at the site of strongest winds in each case. We only have subjective, visual estimates. Based on these data, I don't think that we can suggest that a 130-kt landfall would save more lives than a 145-kt landfall, given the relatively low number of wind-caused deaths in intense tropical cyclones and the varying impacts such winds have on structures, depending on construction standards, the duration of the strongest winds, etc. Well-built, poured-concrete structures can survive winds into Category 5 status, so, for those buildings, there would seem to be little difference between 130- and 145-kt winds. (Case in point: Andrew and Charley made their U.S. landfalls at 145 and 130 kt, respectively, but even in the core, I don't think that any structures experienced the maximum winds. Charley's peak winds passed close to North Captiva Island, but we don't have empirical evidence that homes there encountered 130-kt winds. Andrew's peak, 145-kt winds apparently affected the thinly populated mangroves on the immediate shoreline of Biscayne Bay.) Again, this is just my opinion, and you're welcome to disagree. (I do find it interesting that, given your Southern emphasis on courtesy and due respect, you sometimes come off, at least in my view, as being rather defensive and discourteous in your posts. Maybe honor is a non-negotiable for you, and you may have a trigger finger, but I would appreciate a bit more restraint in your tone, no matter how often others may misconstrue your posts. If you don't like other people's insinuations, then don't descend to their level, please. Just ignore them. That's my friendly advice. )
  23. With changes in the global circulation this winter and early next spring, the 2016 Atlantic hurricane season could the most interesting since 2010. An emerging -PDO and a late-winter/early-spring -NAO would potentially aid in a more moist basin and a resurgent +AMO. Add an emergent La Niña reducing global AAM and you have the potential for lower shear in the Caribbean thanks to reduced forcing in the Pacific. Almost all of the most active Atlantic seasons, ACE-wise, occurred within two years of El Niño episodes. In five of the eight seasons following strong Niños (since 1950), there was an ACE increase of ≥ 33%.
  24. I think that you're contradicting yourself. You previously said that the difference between its hitting at peak strength (175-185 kt) and striking at 130-145 kt could have saved the lives of the iCyclone crew and local residents. You explicitly said, when asked, that the difference between a strong Category 4 and a low-end Category 5 is marginal at best, and in either case, even people in the core, a few blocks inland, would have likely missed the strongest winds. Damage, as you've admitted, would be similar, whether the storm hit at 130 or 145 kt. (If your lack of sleep is affecting the tone of your responses and your perception of reality, please get some sleep. Even an interesting storm isn't worth it. Take my kind advice seriously. )