donsutherland1 Posted May 13, 2012 Share Posted May 13, 2012 2012 Atlantic Hurricane Season Thoughts... Although an El Niño has not developed, I suspect that odds suggest that the development of an El Niño during the summer are probably somewhat more likely than not. ENSO Region 1+2 has been particularly warm in recent weeks and this may suggest that an El Niño is beginning to take hold even as the easterly Trade Winds have recently resumed. The development of an El Niño could suppress mid- and latter-tropical season activity. In addition, the Tropical North Atlantic (TNA) Index, an index that measures the SSTAs in the region bounded by 5.5°N-23.5°N/15°W to 57.5°W, has been cool this spring. May is likely to see another cool TNA. Hence, the first third to perhaps half of the Atlantic hurricane season could also be fairly quiet. An abnormally early tropical cyclone cannot be ruled out, as some of the analog seasons had a late May or June tropical cyclone. Although it is a little soon for me to have a great deal of confidence in the summer/fall pattern, odds seem to favor the highest risk for landfall somewhere along the Gulf Coast. Although the remnants of any such landfalling storm might bring rains to the East Coast, odds of a landfall along the East Coast will probably be below normal. In terms of tropical cyclone activity, my guess for the 2012 Atlantic season is below: Tropical Storms or Hurricanes: 8 Hurricanes: 3 Major Hurricanes: 1 ACE: 55-65 U.S. Tropical Cyclone Landfalls: 2 U.S. Major Hurricane Landfalls: 0 Leading analogs: 1965 and 2009 Link to comment Share on other sites More sharing options...
donsutherland1 Posted May 13, 2012 Share Posted May 13, 2012 That would be an ugly season, to say the least, although with the currently forecasted telecommunications, I can't argue with it either. I was kind of surprised how low my figures came out. Given the success of the analogs during the winter and, to date, spring, I can't find too many strong arguments against a relatively quiet season. For perspective, here are some other forecasts for the 2012 hurricane season vs. my estimates of 8 named storms, 3 hurricanes, 1 major hurricane, and ACE of 55-65: Accuweather: Named Storms: 12 Hurricanes: 5 Major Hurricanes: 2 ACE: No estimate Gray/Klotzbach: Named Storms: 10 Hurricanes: 4 Major Hurricanes: 2 ACE: 70 Tropical Storm Risk: Named Storms: 13 Hurricanes: 6 Major Hurricanes: 3 ACE: No estimate Weather Channel: Named Storms: 11 Hurricanes: 6 Major Hurricanes: 2 ACE: No estimate WeatherBell: Named Storms: 9-12 Hurricanes: 4-6 Major Hurricanes: 2-3 ACE: 75-95 Link to comment Share on other sites More sharing options...
wi_fl_wx Posted May 13, 2012 Share Posted May 13, 2012 It's already clearly "tropical", the hurricane center has never been very good at responding quickly when it comes to genesis. They say they do it to reduce false storms, but they take way too much liberty with that. I don't see how you can call it tropical when the SST is so cold. The SST is 19 C. It's questionable if anything could be called tropical at that SST. There have been systems that formed and looked almost exactly like this one in the Pacific off the coast of Oregon with the same SST. They like to form from cutoff lows because of the vertical instability and the localized low shear. It's basically the definition of a subtropical hybrid storm. But anyway, Jack Bevin has been doing some work on the issue and gave a good presentation at the AMS conference--here's an exerpt from his abstract: "Operational experience at the National Hurricane Center, however, shows that issues of cyclone type analysis remain in determining if a given cyclone is tropical, subtropical, or non-tropical. These issues include: 1) the strength, organization, and longevity of the associated convection, 2) the horizontal and vertical scales, particularly the radius of maximum winds, 3) the nature and evolution of the thermal structure, and 4) the definition of the circulation center." Anyway, the 37 GHz was showing that 3/4 of the clouds were just icy cirrus anyway, there was only one area of sustained convection to the NW of the center. Link to comment Share on other sites More sharing options...
wxmx Posted May 13, 2012 Share Posted May 13, 2012 I don't see how you can call it tropical when the SST is so cold. The SST is 19 C. It's questionable if anything could be called tropical at that SST. There have been systems that formed and looked almost exactly like this one in the Pacific off the coast of Oregon with the same SST. They like to form from cutoff lows because of the vertical instability and the localized low shear. It's basically the definition of a subtropical hybrid storm. But anyway, Jack Bevin has been doing some work on the issue and gave a good presentation at the AMS conference--here's an exerpt from his abstract: "Operational experience at the National Hurricane Center, however, shows that issues of cyclone type analysis remain in determining if a given cyclone is tropical, subtropical, or non-tropical. These issues include: 1) the strength, organization, and longevity of the associated convection, 2) the horizontal and vertical scales, particularly the radius of maximum winds, 3) the nature and evolution of the thermal structure, and 4) the definition of the circulation center." Anyway, the 37 GHz was showing that 3/4 of the clouds were just icy cirrus anyway, there was only one area of sustained convection to the NW of the center. They are tropical if it's warm core (even if it's shallow) and there's sustained convection near the center...even if SSTs are 19C. If the mid-upper troposphere is cold enough, latent heat will be released, with a buoyant column and steep enough lapse rates to sustain convection and some anticyclonic evacuation....this is not quite the case, since it's still inside a broader cyclonic upper low, though some smaller scale anticyclonic fanning could occur if convections deepens just enough. By the way, it looks better, and it will probably be cherried today. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 13, 2012 Share Posted May 13, 2012 Convection is unimpressive. I don't think it gets cherried without more convection. Link to comment Share on other sites More sharing options...
Srain Posted May 13, 2012 Share Posted May 13, 2012 Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 13, 2012 Share Posted May 13, 2012 12z GFS bumps up the development time for this one to around 120-132 hours Catalyst develops around 96 hours Still highly doubt this whole thing. Link to comment Share on other sites More sharing options...
andyhb Posted May 13, 2012 Share Posted May 13, 2012 Develops it pretty explosively off the Carolina Coast a little later in the run as well as it moves into the Gulf Stream...although yeah I have a lot of doubt whether any of this has a prayer of actually occurring. Link to comment Share on other sites More sharing options...
turtlehurricane Posted May 13, 2012 Share Posted May 13, 2012 There is a time threshold definition that is required for the continued production of deep convection over the center of circulation. While the storm did look very tropical earlier today, the convection has waned recently and looks less organized currently. I don't think the organization of the storm persisted long enough today to fit the qualifications of a TC. It lasted at least 12+ hours which is the only time requirement. This isn't the first time the NHC has been so slow to name something that it dissipates. Hopefully they fix the error in post season analysis. Link to comment Share on other sites More sharing options...
turtlehurricane Posted May 13, 2012 Share Posted May 13, 2012 I don't see how you can call it tropical when the SST is so cold. The SST is 19 C. It's questionable if anything could be called tropical at that SST. There have been systems that formed and looked almost exactly like this one in the Pacific off the coast of Oregon with the same SST. They like to form from cutoff lows because of the vertical instability and the localized low shear. It's basically the definition of a subtropical hybrid storm. But anyway, Jack Bevin has been doing some work on the issue and gave a good presentation at the AMS conference--here's an exerpt from his abstract: "Operational experience at the National Hurricane Center, however, shows that issues of cyclone type analysis remain in determining if a given cyclone is tropical, subtropical, or non-tropical. These issues include: 1) the strength, organization, and longevity of the associated convection, 2) the horizontal and vertical scales, particularly the radius of maximum winds, 3) the nature and evolution of the thermal structure, and 4) the definition of the circulation center." Anyway, the 37 GHz was showing that 3/4 of the clouds were just icy cirrus anyway, there was only one area of sustained convection to the NW of the center. The magnitude of the SST has little to do with the definition of a tropical cyclone. What really counts is the SST to tropopause temperature difference. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 14, 2012 Share Posted May 14, 2012 18z GFS ensembles like a TC in the Caribbean as well Link to comment Share on other sites More sharing options...
andyhb Posted May 14, 2012 Share Posted May 14, 2012 Fairly impressive agreement for this early in the season and this far out... Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 14, 2012 Share Posted May 14, 2012 Fairly impressive agreement for this early in the season and this far out... Would be nice to have the foreigners agreeing with the GFS, but with the lack of any interesting weather in the CONUS, I guess we'll just have to work with what we have for now. Disturbance now looks to take shape later this week accoring to the latest GFS. We'll see what happens... Link to comment Share on other sites More sharing options...
phil882 Posted May 14, 2012 Share Posted May 14, 2012 Fairly impressive agreement for this early in the season and this far out... Would be nice to have the foreigners agreeing with the GFS, but with the lack of any interesting weather in the CONUS, I guess we'll just have to work with what we have for now. Disturbance now looks to take shape later this week accoring to the latest GFS. We'll see what happens... I can't buy the GFS, especially when the ECMWF is showing almost exactly what I discussed last week with the more favored basin being the East Pacific. Not only is it more climatologically favored, but the long range statistical forecasts from Paul Roundy show anomalous favorability for TCG in the East Pacific in late May into June. It shall be interesting to see how things play out... although I have to tip my hat towards the ECMWF with the superior resolution and parameterizations that allows it to be better in the tropics. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 14, 2012 Share Posted May 14, 2012 Yeah, EPAC TCG does seem much more promising with this pattern/period, but it's just something to look at until we have something of real interest. Will be interesting to see which model folds first. Moneys on the GFS. (By the way, that ECMWF resolution looks amazing, but just wait until the HWRF receives it's face lift in a few days!) Link to comment Share on other sites More sharing options...
OSUmetstud Posted May 14, 2012 Share Posted May 14, 2012 I can't buy the GFS, especially when the ECMWF is showing almost exactly what I discussed last week with the more favored basin being the East Pacific. Not only is it more climatologically favored, but the long range statistical forecasts from Paul Roundy show anomalous favorability for TCG in the East Pacific in late May into June. It shall be interesting to see how things play out... although I have to tip my hat towards the ECMWF with the superior resolution and parameterizations that allows it to be better in the tropics. Phil, the EC does seem to be hinting at subtropical potential off the US SE Coast. The GFS ensemble MJO forecast looks rather favorable. How does the EC MJO forecasts look? Link to comment Share on other sites More sharing options...
wxmx Posted May 14, 2012 Share Posted May 14, 2012 Phil, the EC does seem to be hinting at subtropical potential off the US SE Coast. The GFS ensemble MJO forecast looks rather favorable. How does the EC MJO forecasts look? Not as favorable Link to comment Share on other sites More sharing options...
am19psu Posted May 14, 2012 Share Posted May 14, 2012 Neither the Aussies nor Roundy show much wave activity on the Atlantic side. http://cawcr.gov.au/staff/mwheeler/maproom/OLR_modes/fmaps.5day.MJO.gif http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdet/7.5S_7.5N/2012.png Link to comment Share on other sites More sharing options...
HM Posted May 14, 2012 Share Posted May 14, 2012 Do these guys have just straight 200mb wind forecasts / CHI? Link to comment Share on other sites More sharing options...
am19psu Posted May 14, 2012 Share Posted May 14, 2012 Do these guys have just straight 200mb wind forecasts / CHI? Not that I have seen. Roundy has some 300mb anomaly forecasts based on the MJO/ER/Kelvin signals, but it's difficult to diagnose equatorial divergence from them. The Aussie products are straight OLR forecasts. Link to comment Share on other sites More sharing options...
HM Posted May 14, 2012 Share Posted May 14, 2012 Not that I have seen. Roundy has some 300mb anomaly forecasts based on the MJO/ER/Kelvin signals, but it's difficult to diagnose equatorial divergence from them. The Aussie products are straight OLR forecasts. That's too bad because that could occasionally be more useful than the classic OLR integrated forecasts. As for strictly CHI, I have nothing against the EWP technique, but it is way too simplified to be always useful. Link to comment Share on other sites More sharing options...
phil882 Posted May 14, 2012 Share Posted May 14, 2012 Do these guys have just straight 200mb wind forecasts / CHI? Not that I have seen. Roundy has some 300mb anomaly forecasts based on the MJO/ER/Kelvin signals, but it's difficult to diagnose equatorial divergence from them. The Aussie products are straight OLR forecasts. Mike Ventrice (http://mikeventrice.weebly.com/) has some nice zonal wind 200 hPa plots that use the GFS forecast in his Hovemoller Tag. I don't know if you were looking for statistical 200hPa/CHI forecasts though or from the operational guidance. In addition, he also has a nice suite of velocity potential plots if you like the smoothed out fields a little better. Link to comment Share on other sites More sharing options...
am19psu Posted May 14, 2012 Share Posted May 14, 2012 Mike Ventrice (http://mikeventrice.weebly.com/) has some nice zonal wind 200 hPa plots that use the GFS forecast in his Hovemoller Tag. I don't know if you were looking for statistical 200hPa/CHI forecasts though or from the operational guidance. In addition, he also has a nice suite of velocity potential plots if you like the smoothed out fields a little better. I like those. I'd like them even more if he had them for more than the GFS Op. Link to comment Share on other sites More sharing options...
carley5 Posted May 14, 2012 Share Posted May 14, 2012 http://www.osdpd.noaa.gov/data/sst/anomaly/2012/anomnight.5.14.2012.gif sst's have warmed a bit. id say 75% in the deep tropics are now above normal. Link to comment Share on other sites More sharing options...
wxmx Posted May 14, 2012 Share Posted May 14, 2012 http://www.osdpd.noa...t.5.14.2012.gif sst's have warmed a bit. id say 75% in the deep tropics are now above normal. A 180° turnaround in the Atlantic pattern has changed things wrt SSTAs. It's too early to know if it will be sustained though. My guess is that TNA for May will have a decent rebound towards 0, if not slightly positive Link to comment Share on other sites More sharing options...
carley5 Posted May 14, 2012 Share Posted May 14, 2012 im still thinking the season wont be as bad as some are saying. 13/8/3. Link to comment Share on other sites More sharing options...
Isopycnic Posted May 16, 2012 Share Posted May 16, 2012 From Facebook: US National Weather Service Tampa Bay Florida Hurricane Fun Fact: The formation of TS Aletta in the eastern Pacific yesterday ended a 41-day streak without a tropical storm anywhere in the world, which marks the longest span Earth has gone without a tropical storm in at least 70 years! Link to comment Share on other sites More sharing options...
HurricaneJosh Posted May 16, 2012 Author Share Posted May 16, 2012 From Facebook: US National Weather Service Tampa Bay Florida Hurricane Fun Fact: The formation of TS Aletta in the eastern Pacific yesterday ended a 41-day streak without a tropical storm anywhere in the world, which marks the longest span Earth has gone without a tropical storm in at least 70 years! Wow. Crazy fact. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 18, 2012 Share Posted May 18, 2012 Internets are buzzing that TWC's Dr. Knabb is returning to NHC... Don't know what it is about Atlanta/TWC. Dr.Lyons escaped to dry, hot, flat San Angelo to get away, no Knabb is leaving? Would be cool to work with real hurricane specialists again, I suppose... Edit- Steve is quick... http://www.americanwx.com/bb/index.php/topic/34570-dr-rick-knabb-announced-as-new-nhc-director/ Link to comment Share on other sites More sharing options...
phil882 Posted May 19, 2012 Share Posted May 19, 2012 Whats that off the NC coast? I think it might still be somewhat attached to the front offshore, but latest Satellite and Radar are certainly intriguing. Link to comment Share on other sites More sharing options...
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