vortex95

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  1. K63S - Colville WA KADT - Atwood KS KDWA - Davis/Yolo County CA KK62 - Falmouth KY KOAR - Marina CA KU69 - Duchesne UT PAKX - Port Alsworth AK
  2. Goni as strong as Haiyan? Going strictly by satellite here. I did a comparison of EIR and BD geostationary imagery (4 km resolution) at Goni's and Haiyan's peak intensity of 170 kt. Goni EIR 10/31/20 18z 170 kt https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2020wp22/4kmirimg/2020wp22_4kmirimg_202010311800.gif Haiyan EIR 11/7/13 1830z 170 kt https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2013wp31/4kmirimg/2013wp31_4kmirimg_201311071830.gif Goni BD 10/31/20 18z 170 kt https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2020wp22/4kmsrbdc/2020wp22_4kmsrbdc_202010311800.jpg Haiyan BD 11/7/13 1830z 170 kt https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2013wp31/4kmsrbdc/2013wp31_4kmsrbdc_201311071830.jpg Haiyan looks more symmetrical with a thicker/colder CDO ring and warmer/clearer eye. ----- Comparison of Polar EIR imagery (1 km resolution) Goni EIR 10/31/20 1225z https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2020wp22/1kmirimg/2020wp22_1kmirimg_202010311225.gif Haiyan EIR 11/7/13 1640z https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2013wp31/1kmirimg/2013wp31_1kmirimg_201311071640.gif Polar imagery is not at the same time but still Haiyan looks so much more impressive overall for its cold COD ring and a warmer/clearer eye overall. Geostationary imagery for Goni at 18z does not suggest its satellite presentation improved to this level from 1225z.
  3. USAF did do recons in the WPAC (mostly out of Guam) until 1987. That's when I think full reliable geostationary coverage (GMS satellite) was available. It is virtually without a doubt there have been several STYs in the WPAC stronger than STY Tip. Haiyan (2013) and Zeb (1998) are likely candidates. A few more are discussed here: https://ams.confex.com/ams/26HURR/techprogram/paper_75465.htm https://ams.confex.com/ams/pdfpapers/75465.pdf Many TCs globally, weak and strong, are underestimated when no recon is present. Dvorak does best with systems 60-105 kt. This mean two things 1) a lot of TDs are actually weak TSs, and 2) the most intense TCs are often underestimated, sometimes by significant values. The smaller, more intense a TC is, the greater the error. Dvorak does not do well for small/tiny intense TCs. No way we would ever have got 215 mph for Patricia based on satellite, even if it was an average size TC. Usually TC centers will max 1-min winds at 185 mph for satellite-only estimates, such as EPAC Linda 1997 (likely strong than 185 mph). JTWC until Haiyan never went about 185 mph satellite-based only. Even Haiyan's 195 mph is only an estimate. In the hurricane re-analysis project for the Atlantic, adjustments to the most intense TCs are capped at 185 mph. Just no way to tell what really goes on in these mesoscale cores of intense TCs without recon, even with direct pressure readings as we now know how variable the winds can be for a given eye pressure. I will say with the FL Keys Labor Day hurricane in 1935, an 892 mb pressure and RMW smaller than Andrew's, and 30 mb lower than Andrew, that meant the winds were probably ~200 mph.
  4. METAR: KORK - North Little Rock AR KRVJ - Reidsville GA KT69 - Sinton TX PHHN - Hana HI PHMU - Kamuela HI RAOB: 72413 - Sterling Field VA 38.97/-77.48 89m
  5. SFMR is used extensively in many hurricanes now, so I would think it would be at leastsomewhat relevant. And dropsondes have limitations as well. They measure instantaneous wind, not a 1-min avg, so it is not as straightforward as the raw data shows. It has to go through QC and other checks before it is considered a representative wind measurement.
  6. Here is a complete list. Most Intense Atlantic Hurricanes by Central Pressure ---------------------------------------------------- Name Date Pressure (mb) Wilma Oct 2005 882 Gilbert Sep 1988 888 "Labor Day" Sep 1935 892 Rita Sep 2005 895 Allen Aug 1980 899 Camille Aug 1969 900 Katrina Aug 2005 902 Mitch Oct 1998 905 Dean Aug 2007 905 Maria Sep 2017 908 "Cuba" Oct 1924 910 Ivan Sep 2004 910 Dorian Sep 2019 910 Janet Oct 1955 914 Irma Sep 2017 914 Isabel Sep 2003 915 * Opal Oct 1995 916 ** "Camaguey" Nov 1932 918 Hugo Sep 1989 918 Gloria Sep 1985 919 ** Michael Oct 2018 919 Hattie Oct 1961 920 "Great Abaco" Sep 1932 921 Floyd Sep 1999 921 ** Andrew Aug 1992 922 * estimated ** not Category 5
  7. This makes me wonder about the calibration of the SFMR. There has been concern with the calibration since 2016, and this is an ongoing active area of study. It seems to have a high bias for extreme winds. I mean look at Dorian, 910 mb and 185 mph? Ok, Gilbert 888/185 and Wilma 882/185, and Gilbert and Wilma had pinhole eyes. Dorian had a large eye, like Laura does now. Matthew 160 and only 941? That's the highest wind for a the highest pressure for a Cat 5 in the Atlantic. Charley's 150/941 a makes sense since it has a pinhole eye and was undergoing very strong RI at the time. it's one of two things, either the SFMR winds are correct and thus we have to go back and adjust winds up for many historical intense hurricanes, or it high bias is real and recent intense Atlantic TC winds need to be adjusted down. Operationally, Irma's winds were 185 mph, but in post-season analysis, they were lower to 180 mph presumably b/c of the high SFMR bias. The Labor Day Hurricane in 1935 was 892 mb and assigned 185 mph in re-analysis, but I believe intensity is capped at 185 mph for pre-recon hurricanes in the Hurricane Re-analysis Project. This hurricane was very small (smaller RMW than Andrew) and given what we know now about hurricane structure and dynamics, chances are good it had winds around 200 mph. It gets quite tricky to determine the true strength of very intense TCs w/o actual in situ data. And the smaller they are, the harder it is, even in this day and age with advanced satellites. The Dvorak scale does not do well with small intense TCs overall.
  8. Exactly, the first RI is often the most intense part of the TC. After that, the ERCs expand the wind field, so it is hard to really tighten them up again b/c of the internal stability of a larger vortex (I think that is the reason). Not saying you can't get re-intensification and RI after the first RI ((look at Hugo in Sep 1989 that last day leading up to landfall), but typically you won't get a pinhole eye which usually has the absolute highest winds. You'll have a large eye with the overall wind field spread out, not all focused tightly right around the eye. Laura doesn't have a pinhole eye I think b/c of its latitude. It's hard to get pinhole eyes outside the deep tropics since Coriolis is higher at say 30N vs. 15N.
  9. Not it wasn't personal. Just calling it as I saw it in the here and now, and looking at the synoptic pattern. Laura had been struggling it seemed forever, and I didn't see the overall environment changing much today. Dry air was still present just to its NW and shear was forecast to increase. But TCs are strange beasts, and small-scale factors can take over since were are dealing with TC inner cores, which are often on the mesoscale, so the synoptic factors can become a non-issue at times. As everyone knows, intensity forecasting for TCs is probably one of the most challenging aspects of the field.
  10. Well, I am sure eating humble pie! Laura is doing what Harvey and Michael did. But at the time of my above post, doing a nowcast from that was not that unreasonable. However, the atmosphere is always throwing curves at us and all of us will be burned some of time. This is Laura's first RI, not a system that got strong early in its existence. Florence in 2018, as one example, was different. Multiple ERCs well before landfall, and had expanded in size with the wind field spread out, and that's one reason why it didn't intensify near landfall despite going over the Gulf Steam (weakened a lot in fact). It's easier to tighten up a TC the first time (no RI prior in its existence). Laura had struggled all along and now makes its move at the last min.
  11. Yes, I know. Laura is doing what Harvey and Michael did. But at the time of the above post, doing a nowcast from that was not that unreasonable. However, the atmosphere is always throwing curves at you and all us of will be burned some of time. This is Laura's first RI, not a system that got strong early in its existence. Florence in 2018 was different. Multiple ERCs well before landfall, so it had expanded in size with the wind field spread out, and that's one reason why it didn't intensify near landfall despite going over the Gulf Steam (weakened a lot in fact). It's easier to tighten up a TC the first time (no RI prior in its existence). Laura had struggled all along and now makes its move at the last min.
  12. The asymmetries in the CDO suggest still some dry air is getting ingested in the W quad. You can see small areas of bursting very cold IR cloud tops just W of the center and a partial erosion of the colder cold tops on the W side of the hurricane. The CDO as a whole is having trouble organizing into a smooth circular pattern with uniform cold cloud tops. Outflow is being persistently restricted in the W quad and doesn't seem to have linked up with the trough over ern TX to provide a large anticyclonic poleward outflow channel that is often key to RI (Harvey and Michael did have strong poleward outflow channels). So even though conditions have improved the last 12 hours, they are not ideal. The patch of dry air in the wrn GOMEX persists. The shear, which did relax during the day Tuesday, was initialized at 3 kt at 00z by the SHIPS output. 06z it has 13 kt and it stays close to this value until landfall. The window of opportunity for RI may be closing. http://hurricanes.ral.ucar.edu/realtime/plots/northatlantic/2020/al132020/stext/20082600AL1320_ships.txt
  13. Agree with all here. It is getting act together finally. Just have to smooth things out with the active convective blobs around the center. It will likely take another 6-8 hr to get in a position for significant RI. The large, discrete convective blob to S is going away as well. Now looking more like a typical hurricane.
  14. I wasn't throwing in the towel and I was not being irresponsible. Laura is a significant threat. Just pointing caveats on its intensity potential. And I did acknowledge there is a transition time by using the words "gradually" and "with time" "You want to see a smooth ring of convection gradually develop, and cool with time, and wrap around the center, and most importantly, persist for more than just a couple of hours." NHC points out the caveats in terms of dry air and shear well in the 4pm CDT discussion. They say dry air could still be a factor but don't go with it explicitly for now. Shear will be a factor 6-12 hr before landfall, so it is prudent to not go too aggressive in the intensity at this point. They did not change their intensity forecast at landfall from 10am CDT.
  15. That is a valid and reasonable statement. Wait until you see some consistency in the convective organization, and less of transient, sharp-edged very cold IR blow-ups. I'd be more bullish on sooner RI if the entire system was not so elongated N S and that blob of discrete convection well S of the center didn't exist.