GaWx

The 12Z Euro is another that still has nothing of significance, far different from the GFS/CMC/Euro-AI. The 12Z GEFS favors FL including panhandle whereas the GEPS is about 50% FL Big Bend south and 50% E LA to AL. For those not familiar: Operationals are of limited use this far out because they’re like throwing darts to a pretty far away dartboard. The ensemble members are also darts to a far away dartboard but there are a bunch of darts at once to better give us tendencies/trends.

Indeed, I agree that CC/AGW is real and significant. My point to TT was that the UHI portion for large cities like Phoenix and LV shouldn’t be dismissed as insignificant. He said, “I’ve never bought it that the urban he Island is a big enough factor in this thing”. That’s what I was responding to. Perhaps I misinterpreted him. Maybe he just meant that UHI isn’t the dominant metric, which I’d lean toward though I could see it approach 50% in some of the faster growing large metros like LV.

Yeah, I realize that we’ve all been looking at Atlantic ACE only and I still feel like you that there’s a notable negative correlation of that and SSN. This graph is based on worldwide MH count, obviously not at all the same as ATL ACE. If I get the time, I may due to curiosity look at just Atlantic MH to see if there appears to be a decent inverse correlation to SSN. One would think so but you never know. Regardless, the worldwide MH count apparently not negatively correlating to SSN admittedly makes me wonder why. Could there be something about the Atlantic that makes it more conducive to negatively correlating to SSN than other basins? If so, I wonder what that could be. Interesting to think about!

Below is a repost of that Ryan Maue graph posted earlier today. Note that the global MH freq is the sum of the prior 3 years as opposed to the 3 years centered on that date. If this had instead been the latter, it would have suggested a notable inverse relationship of global MH frequency and SSN. But it isn’t. Calculations 1/86: MH 3 yr sum peak 71/SSN prior 3 yr avg 57 1/89: MH 3 yr sum dip 56/SSN prior 3 yr avg 64 9/94: MH 3 yr sum peak 92/SSN prior 3 yr avg 100 7/01: MH 3 yr sum dip 62/SSN prior 3 yr avg 148 3/07: MH 3 yr sum peak 87/SSN prior 3 yr avg 41 10/13: MH 3 yr sum dip 55/SSN prior 3 yr avg 81 9/16: MH 3 yr sum peak 94/SSN prior 3 yr avg 82 3/23: MH 3 yr sum dip 53/SSN prior 3 yr avg 51 Analysis -Highest MH 3 yr sum peaks (94, 92) when prior 3 yr SSN avg not low (82, 100) -Lowest MH 3 yr sum dips (53, 55) when prior 3 yr SSN avg not high (51, 81) -So, two highest MH 3 yr sum peaks (avg 93) had avg prior 3 yr SSN avg up at 91 while two lowest MH 3 yr dips (avg 54) had avg prior 3 yr SSN down at 66. Conclusion I can’t conclude that there’s even a very limited negative correlation of SSN and worldwide MH based on this data. The graph is deceiving (not necessarily intentional). Had this same graph been measuring 3 yr MH sums centered on each date instead of the 3 yrs prior, I would have concluded a decent negative correlation of MH count and SSN just from looking at this with no calculations needed. But it’s not. Those MH peaks/dips that you see are the sums of the 3 years prior. So, you can’t just look at those MH peaks/dips (blue) and go directly down to the SSN (red). You instead have to look at the avg of the reds for the 3 yrs prior to each MH peak/dip. Monthly SSN: https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt

For the 8th run in a row the CMC has a TC form in the W Caribbean 9/21-2 and move N toward the U.S. The 0Z GFS also has a similar storm that comes in a little later. Before that interestingly enough, it does something similar to the 12Z Euro forming a weak LLC SE of NYC at least partially from the remnants of PTC-8. It similarly moves S and gets down to 1001 mb. But instead of turning W to NC, it then turns SW and goes over C FL while opening up.

The CRW Nino 3.4 updated for the first time in two months! It has usually been either very close to or slightly warmer than OISST. But currently it is slightly cooler at -0.38: OISST has resumed cooling (now at -0.28):

The Euro Weeklies, which have been quite impressive both with the very active early season as well as the relatively quiet peak season, are like they have for many days still calling for weekly ACE rising to near normal late Sep and to well above normal in the first 2 weeks of Oct, like it or not.

The Phoenix area has grown nearly tenfold since 1960 and is now at 4.8 million. It has doubled in size just in the last 30 years. Minimizing the importance of UHI as a significant factor seems presumptuous to me. I’m not saying I think it is larger than CC (I fully believe in AGW), but rather I’m saying I think it is far from trivial and that it wouldn’t surprise me if it something like 30-40%: https://www.macrotrends.net/global-metrics/cities/23099/phoenix/population

The late portion of the 12Z Euro with its TC heading W toward NC is more of a fwiw/mainly for entertainment run than the late portion of the 12Z CMC imo because unlike the CMC this Euro is very different from prior Euros. Interestingly, this isn’t at all from a tropical origin and is instead related to a combo of PTC-8’s vorticity going NE and the vorticity associated with that 32N, 70W circulation that I mentioned earlier going N. They combine and get stuck near NYC under a new Rex block. Then a new surface low forms Wed night (only 60 hours from now), moves S, and then turns W late. I want to first see if there will even be a surface low that forms SE of NYC wed night. Also, I’m going to keep watching that circulation near 32N, 70W as it heads N.

FEMA/NFIP flood insurance covers flooding from heavy rain from whatever the source. But homeowner’s normally doesn’t pay for flooding from rainfall. It pays to have FEMA/NFIP. It isn’t even expensive outside of high risk flood zones. https://flood.nc.gov/ncflood/insuranceagent.html#:~:text=Is flood insurance available everywhere,NC communities are participating communities.

This was even worse than Florence in some areas due to it falling within a much shorter period of time. This shows you don’t need a TS or STS to have near biblical effects.

This is unreal and very sad (from PTC 8):

Thanks. Normally I’d treat the Crazy Uncle at 222 with little significance. However, it has had this storm every run since the 12Z of 9/13 with similar timing (all originating in the SW Caribbean ~9/21) and fairly similar tracks. Plus it has good ensemble support along with climo support. Euro Weeklies in a general sense have been calling for something like this for several weeks. 12Z CMC 222:

Note what looks like a circulation near 32N, 70W. This came from that further east convection that was separate from PTC8. It likely will never amount to much, regardless, though it is interesting to see.

The various ensembles overall continue to look fairly active for late Sept. with FL possibly in the crosshairs from a Caribbean originating storm.

Potential Tropical Cyclone Eight Discussion Number 2 NWS National Hurricane Center Miami FL AL082024 1100 PM EDT Sun Sep 15 2024 The Potential Tropical Cyclone (PTC) has become a bit better organized tonight, with deep convection on the northeast side of the circulation. Additionally, the last aircraft pass just north of the estimated center of the system indicated that the temperature gradient from east-to-west had weakened. However, it is still unclear whether a well-defined center exists looking at the latest satellite and radar animations, with the center that the plane found earlier looking somewhat elongated. For now, the system will remain a Potential Tropical Cyclone, and the winds are set to 40 kt. An Air Force Reserve reconnaissance aircraft is scheduled to be in the area overnight for a better look at the system's structure. It appears the system has only drifted northwest since this afternoon. The PTC should move a bit faster to the northwest on Monday and Tuesday due to flow from a ridge over the northeastern United States. There is general agreement on this track in the models, though they differ on the speed. The new forecast is trended a bit slower than the last one, but not as slow as the ECMWF model. The system has a high chance of being a tropical cyclone early tomorrow, and some strengthening is possible before landfall as it moves over warm waters with a conducive upper-level trough interaction. The official forecast is similar to the latest decay-SHIPS model guidance and the prior forecast. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 32.2N 77.9W 40 KT 45 MPH...POTENTIAL TROP CYCLONE 12H 16/1200Z 32.8N 78.5W 45 KT 50 MPH...TROPICAL CYCLONE 24H 17/0000Z 33.6N 79.3W 35 KT 40 MPH...INLAND 36H 17/1200Z 34.5N 80.0W 25 KT 30 MPH...POST-TROPICAL 48H 18/0000Z 35.5N 80.7W 20 KT 25 MPH...POST-TROPICAL 60H 18/1200Z 36.6N 81.0W 20 KT 25 MPH...POST-TROPICAL 72H 19/0000Z 36.5N 80.5W 20 KT 25 MPH...POST-TROPICAL 96H 20/0000Z...DISSIPATED $$ Forecaster Blake

Potential Tropical Cyclone Eight Advisory Number 2 NWS National Hurricane Center Miami FL AL082024 1100 PM EDT Sun Sep 15 2024 ...POTENTIAL TROPICAL CYCLONE MOVING SLOWLY OFF THE COAST OF THE CAROLINAS... ...EXPECTED TO BRING HEAVY RAINS AND COASTAL FLOODING... SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...32.2N 77.9W ABOUT 125 MI...200 KM ESE OF CHARLESTON SOUTH CAROLINA ABOUT 180 MI...295 KM SSW OF CAPE LOOKOUT NORTH CAROLINA MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...NW OR 320 DEGREES AT 5 MPH...7 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Edisto Beach, South Carolina northward to Ocracoke Inlet, North Carolina For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 1100 PM EDT (0300 UTC), the disturbance was centered near latitude 32.2 North, longitude 77.9 West. The system is moving toward the northwest near 5 mph (7 km/h), and this general motion is expected through Tuesday. On the forecast track, the center of the system should reach the coast within the warning area on Monday. Maximum sustained winds remain near 45 mph (75 km/h) with higher gusts. This system is likely to become a tropical storm overnight or tomorrow morning, and some strengthening is possible before the system makes landfall. * Formation chance through 48 hours...high...80 percent. * Formation chance through 7 days...high...80 percent. Tropical-storm-force winds extend outward up to 175 miles (280 km) from the center. The estimated minimum central pressure is 1006 mb (29.71 inches).

No: https://kamala.cod.edu/nc/latest.wgus62.KRAH.html

Thanks. That shows competing convection, which might keep it from strengthening. Note also that SSTs are highest where it is now (~84-5). As it moves toward the Carolinas, SSTs drop to 77-8.

That’s good for a change. 3 for 3 hurricane hits on the CONUS during just the 1st half of the season was highly unusual. Hopefully I’m not jinxing it.

W winds to 43 knots? Is that right? Extrap SLP 1010 mb there. 05204730 3148N 07710W 8417 01578 0095 +162 +139 239037 041 033 008 03204800 3147N 07711W 8431 01565 0099 +165 +129 260038 041 029 007 00204830 3146N 07711W 8432 01564 0095 +172 +122 269040 043 029 008 00204900 3144N 07712W 8417 01581 0099 +168 +114 262032 038 029 008 00204930 3143N 07713W 8422 01576 0102 +163 +115 273029 031 026 008 00205000 3142N 07714W 8436 01559 0105 +154 +129 269022 027 022 009 00205030 3140N 07712W 8420 01579 0100 +166 +117 272025 027 022 003 00205100 3139N 07711W 8431 01572 0103 +166 +129 266021 026 020 002 00205130 3138N 07709W 8428 01575 0103 +172 +120 257023 028 020 000 00

Newest recon data suggests pretty tight LLC near 31.9N, 77.5W. Highest winds nearby at 48 knots? Extrapolated SLP 1006 mb? Is this right? 203200 3158N 07735W 8432 01547 0066 +188 +103 328038 041 041 005 00 203230 3156N 07734W 8426 01552 0063 +191 +097 309039 041 042 005 00 203300 3154N 07733W 8425 01554 0064 +193 +097 294039 040 041 004 00 203330 3153N 07732W 8430 01552 0073 +181 +102 297038 041 035 005 00 203400 3152N 07730W 8418 01564 0076 +174 +106 299038 039 /// /// 03 203430 3153N 07729W 8416 01562 0064 +189 +094 288041 042 022 005 00 203500 3155N 07728W 8435 01537 0066 +176 +104 296048 052 030 014 00 203530 3156N 07727W 8412 01545 0072 +131 //// 320026 051 045 038 04

No upgrade but NHC is initiating advisories on PTC 8 at 5PM EDT: https://x.com/nhc_atlantic/status/1835410217334603844

Assuming I’m decoding recon data correctly, I’m seeing W winds at 20 knots at 31.6N, 77.7W and extrapolated SLP of 1007.4 mb. Should be enough for an upgrade to T or ST unless I’m misinterpreting the data.

It’s tricky because even if there were no LLC the high to the N would on its own be causing brisk winds though likely not the 49 knots that’s apparently been measured. Is the clear twist that we’re seeing at the surface? Are there W winds? Are dewpoints much lower to the north?