ALhurricane Posted September 12, 2018 Share Posted September 12, 2018 A dropsonde measured 116kt in the east eyewall. Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 12, 2018 Share Posted September 12, 2018 Anyone notice that the whole SW quad had really large 700mb dewpoint depressions? 37 percent RH on the first dropsonde too. Link to comment Share on other sites More sharing options...
Windspeed Posted September 12, 2018 Share Posted September 12, 2018 Agree on the Cat 3 intensity. However, the windfield is expanding. This poses an increase in surge potential for a slow-moving landfall or stall near landfall. Greater fetch. Additionally, even with expansion of windfield, favorable environmental conditions can still result in intensification of the core vortex. We still have a long ways to go. It wouldn't be unrealistic for reintensification back to a Cat 4 and then additional weakening trend near landfall. Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 12, 2018 Share Posted September 12, 2018 3 minutes ago, ALhurricane said: A dropsonde measured 116kt in the east eyewall. Mean lowest 150 m wind doesn't support it. Maybe it's a gust. Link to comment Share on other sites More sharing options...
ALhurricane Posted September 12, 2018 Share Posted September 12, 2018 1 minute ago, OSUmetstud said: Mean lowest 150 m wind doesn't support it. Maybe it's a gust. Good point. May be enough though there where they keep it a 110kt Cat 4 for the Advisory. Link to comment Share on other sites More sharing options...
jayson Posted September 12, 2018 Share Posted September 12, 2018 2 minutes ago, StormFollowerUSA said: Didn't Harvey intesy to a category 4 just before landfall? Harvey happened in August, further south, in 90 degree SSTs. 1 Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 12, 2018 Share Posted September 12, 2018 Just now, ALhurricane said: Good point. May be enough though there where they keep it a 110kt Cat 4 for the Advisory. I could see 110 kt for sure. But that's 3 lol. Link to comment Share on other sites More sharing options...
Windspeed Posted September 12, 2018 Share Posted September 12, 2018 Didn't Harvey intesy to a category 4 just before landfall? Harvey had exceptional upper atmospheric environmental conditions on approach, a tight vortex and 30-31°C up to the shoreline. Florence is a much larger hurricane. It's not impossible that Florence could make landfall as a Cat 4, it's just not as likely based on slow movement in a less favorable environment. 5 Link to comment Share on other sites More sharing options...
NYCGreg Posted September 12, 2018 Share Posted September 12, 2018 I'm no expert, but the one hour improvement on satellite was pretty impressive, given that the SW side tightened up a bit and the eye is circular and clear now. Again, just going off of what I read, it is not that odd for a hurricane to struggle a bit coming off an ERC, and people here have noted that pressure falls may precede an increase in wind. Guess we'll have to see what happens here., but I don't see how people can discount continued weakening or rapid intensification. We've seen that it does not take a long time for these systems to gain an incredible amount of strength, and that could very well happen here. 1 Link to comment Share on other sites More sharing options...
StormFollowerUSA Posted September 12, 2018 Share Posted September 12, 2018 1 minute ago, jayson said: Harvey happened in August, further south, in 90 degree SSTs. You right. Link to comment Share on other sites More sharing options...
hazwoper Posted September 12, 2018 Share Posted September 12, 2018 Pressure has actually dropped since 8pm update Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 12, 2018 Share Posted September 12, 2018 2 minutes ago, Windspeed said: Harvey had exceptional upper atmospheric environmental conditions on approach, a tight vortex and 30-31°C up to the shoreline. Florence is a much larger hurricane. It's not impossible that Florence could make landfall as a Cat 4, it's just not as likely based on slow movement in a less favorable environment. I wonder if the NHC will start to acknowledge the less than ideal environment. This storm is undergoing effects beyond the Erc. Im no expert but i l think it's been clear on satellite for much of the day. 1 Link to comment Share on other sites More sharing options...
LongBeachSurfFreak Posted September 12, 2018 Share Posted September 12, 2018 6 minutes ago, NYCGreg said: I'm no expert, but the one hour improvement on satellite was pretty impressive, given that the SW side tightened up a bit and the eye is circular and clear now. Again, just going off of what I read, it is not that odd for a hurricane to struggle a bit coming off an ERC, and people here have noted that pressure falls may precede an increase in wind. Guess we'll have to see what happens here., but I don't see how people can discount continued weakening or rapid intensification. We've seen that it does not take a long time for these systems to gain an incredible amount of strength, and that could very well happen here. That’s exactly why intensity forecasting is so challenging. And the following conflicting factors. Going for Florence we have increasing SST and higher OHC plus a low shear environment. Going against Florence we have a relatively dry ascendant airmass. Now that Florence has increased in size I think it will Be tough for much strengthening past a low end cat 4 something like 120kts. If you want to see what truly perfect conditions and incredible OHC check out mangkhut. 1 1 Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted September 12, 2018 Share Posted September 12, 2018 Maximum surfaces are 120mph in the NW eyewall Link to comment Share on other sites More sharing options...
ALhurricane Posted September 12, 2018 Share Posted September 12, 2018 32 minutes ago, OSUmetstud said: I could see 110 kt for sure. But that's 3 lol. Yes, yes it is. Lol. It’s been a long day... Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 12, 2018 Share Posted September 12, 2018 3 minutes ago, ALhurricane said: Yes, yes it is. Lol. It’s been a long day... It's all good Link to comment Share on other sites More sharing options...
winterymix Posted September 12, 2018 Share Posted September 12, 2018 The NAM is the NAM but still, it is American so we should look at it. The NAM has no landfall during the entire run. Florence wanders the coastline out to "hour 84". Will it verify just so? Nope. Still a few other model runs have had a close brush with the coast but no Carolina LF during the next 96 hours or so. It is not impossible that LF may be delayed or extra-tropical. Link to comment Share on other sites More sharing options...
Hoosier Posted September 12, 2018 Share Posted September 12, 2018 Still 140 mph on the new advisory. 1 Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted September 12, 2018 Share Posted September 12, 2018 NHC holds at Cat 4 because of SATCON 1 Link to comment Share on other sites More sharing options...
weathafella Posted September 12, 2018 Share Posted September 12, 2018 I think they held d/t what’s happened in the past few hours. Link to comment Share on other sites More sharing options...
jayson Posted September 12, 2018 Share Posted September 12, 2018 Guidance moved to the south. Link to comment Share on other sites More sharing options...
David Reimer Posted September 12, 2018 Share Posted September 12, 2018 I can see why they held it at 140 MPH. No need to make knee-jerk down/up revisions. They'll give it another few hours to see if winds start responding back up. If not, they can start reducing winds. Surface pressures are lowering. As I explained last night, the larger wind-field is helping keep the winds from responding upwards for now. As a 'rubber-band effect', the winds could respond upward quite quickly in the next 12-18 hours if the pressure keeps falling. We've seen it in several intense hurricanes after ERWC. The wind being held at 140 MPH is probably being done for societal reasons versus pure scientific. The post-storm report will undoubtedly revise intensity estimates as needed. 3 1 Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted September 12, 2018 Share Posted September 12, 2018 58 minutes ago, jayson said: Harvey happened in August, further south, in 90 degree SSTs. I don't think its an apples to apples comparison, though....Harvey was in the maturing part of its life cycle. Once they have matured, gone through ERCs etc, it can be tricky as far as seeing extended periods of bonafide intensification. I think we've seen peak intensity, but just an educated guess. Link to comment Share on other sites More sharing options...
ncskywarn Posted September 12, 2018 Share Posted September 12, 2018 GFS is running almost smack dead on top of 18Z at hour 24. Link to comment Share on other sites More sharing options...
Random Chaos Posted September 12, 2018 Share Posted September 12, 2018 When an eyewall is open, the wind field expands and while pressure may stay low the gradient is lessened (and thus the wind field expands while the wind at the eyewall drops). During today's ERC there was a long periods of an open eyewall, and this is one reason why we are seeing the wind field lower than expected for the storm. The result is going to be TS and hurricane force winds at a larger radius, but a less intense eyewall. The eyewall may recover these winds if the central pressure keeps falling, but it's really a wait-and-see state. Looking at WV loop, it does look like there is some dry air it is ingesting to the SW. This seems to be what is contributing to the ragged appearance: Link to comment Share on other sites More sharing options...
ncskywarn Posted September 12, 2018 Share Posted September 12, 2018 GFS is a touch NE at hour 36. Link to comment Share on other sites More sharing options...
DopplerWx Posted September 12, 2018 Share Posted September 12, 2018 gfs back to over strengthening florence, 927mb offshore vs 941mb at 12z at hr60 Link to comment Share on other sites More sharing options...
yoda Posted September 12, 2018 Share Posted September 12, 2018 Florence stalling SE of ILM at 60 Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted September 12, 2018 Share Posted September 12, 2018 Recon showing the stronger winds are making it further down now Link to comment Share on other sites More sharing options...
Cooper08 Posted September 12, 2018 Share Posted September 12, 2018 5 minutes ago, yoda said: Florence stalling SE of ILM at 60 48 to 66 is basically a stall with slight movement while it appears at 66 to be very close to LF... Link to comment Share on other sites More sharing options...
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