GaWx

I'm becoming increasingly concerned down here for potential huge impacts if a worst case scenario of a major hurricane FL landfall and subsequent track too close to this area were to materialize. In that worst case scenario, it would likely be difficult to deal with due to complicating family circumstances (disability related). Not a pretty situation as it looks now for here Wednesday/Wednesday night: From NWS at CHS: WEDNESDAY: MUCH OF WEDNESDAY INTO WEDNESDAY NIGHT WILL BE DOMINATED BY IDALIA. 27/12Z GUIDANCE HAS SHIFTED EAST A BIT AND A TAD FASTER. THE LATEST NHC FORECAST SHOWS INCREASING PROBABILITIES FOR BOTH TROPICAL STORM AND HURRICANE CONDITIONS, BUT IT IS STILL TOO SOON TO TALK SPECIFICS WITH RESPECT TO DETERMINISTIC WINDS FOR THE LOCAL AREA. MUCH WILL BE DETERMINED ON HOW IDALIA RESPONDS TO CONDITIONS OVER THE EASTERN GULF OF MEXICO AND HOW IT TRACKS OVER NORTHERN FLORIDA. SUFFICE TO DAY, CONFIDENCE IS INCREASING THAT SOME DEGREE OF IMPACTS, POSSIBLY SIGNIFICANT, WILL OCCUR ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. IN ADDITION TO POSSIBLE TROPICAL STORM AND/OR HURRICANE CONDITIONS, HEAVY RAINFALL AND FLOODING WILL BECOME AN ISSUE, ESPECIALLY WITH ELEVATED HIGH TIDES EXPECTED AND A PRE POTENTIALLY ONGOING. THIS WILL ONLY ENHANCED THE RISK FOR FLASH FLOODING, ESPECIALLY AT THE COAST. THERE IS STILL PLENTY OF TIME TO PIN DOWN THE HEAVY RAIN, WIND AND TIDE FORECASTS, AND HOW THEY WILL INTERPLAY. EXPECT A VARIETY OF HYDROLOGIC, TROPICAL AND SURGE/COASTAL FLOODING HEADLINES WILL BE NEEDED AT SOME POINT, POSSIBLY AS EARLY AS MONDAY AFTERNOON.

I'm becoming increasingly concerned even up here for potential major impacts if a worst case scenario of a major hurricane FL landfall and subsequent track too close to this area were to materialize. In that worst case scenario, it would be difficult to deal with due to complicating family circumstances (disability related). Ugh

The record high Nino 4 per the monthly OISST table back to 1982 is 30.22 (Nov of 2015). The 2nd warmest Nino 4 is 29.84 and is a tie (Nov of 2009 and Dec of 2015). Aug of 2023 is projected to be ~29.64. But the warmest Aug, alone, is the 29.42 of 2015. So, that will be easily passed. It will be interesting to see what the Nino 4 peak will be. If I'm not mistaken, the warmest models (BoM, Euro, Meteo-France and JMA) have it getting to ~30.40-30.45. But the coolest (CFS and UKMET) only get it to ~29.80. Of course, the warming globe is a big factor in making attaining records easier in all regions. The record warmest for June and July were in 2015 with 2018 second and 2023, third.

Agreed 100%. I was just going further with that Tweet and excluding the Big Bend. In the stretch from Cedar Key south to just N of TB, a whopping ~15 (30%) of 12Z EPS members cross!

The 12Z UKMET was about same as 0Z with landfall closer to the center part of FL Big Bend (~50 miles NW of Cedar Key) moving NNE.

So, the 12Z EPS has 4 members out of 51 (8%) with a landfall south of the Big Bend and N of Tampa Bay, the most dangerous track for Tampa Bay. That's nothing to take lightly but there's lots of hope it won't happen as the odds are quite low based on this.

Regarding that Tweet assuming he is excluding both the Big Bend and Tampa, themselves, when he says "between", it would be extremely difficult though not impossible for Idalia to cross the coast in that stretch because most guidance shows it still moving NNE at that latitude and that part of the coast is angled NNE. October, when headings are more commonly NE to E, is usually a more dangerous period for that to happen.

Indeed, Hermine was a solid H with 981 mb near landfall in the Big Bend. Beware of inaccurate Tweets. He even shows Hermine landfalling into the upper part of the Big Bend! If he means "between exclusive" instead of "between inclusive", then that's different. But "between exclusive" would be just a rather short portion of the coast centered on Spring Hill at a difficult angle to have a landfall. In that case, I don't think there's even been a TS crossing since 1968 (excluding 1968, itself, which had Gladys).

It is just JB looking at ONE cold run of a terrible model even though the last 12 averaged out show slightly warmer than normal. He's not going to show mild runs, of course. Also, JB said nothing nor showed anything addressing snow in his tweet. This is what he said: "what a CFSV2 run for JFM. whats interesting is it has a correlation to our chief analogs. Cold tries to come in November, December opposite of last year is warm then the hammer comes down. Gotta to migrate the warmest water into enso 3.4 for winter. ( Migrating Modoki)" -------------- Now just because JB does this all of the time doesn't mean he can't be right this time as a broken clock is right twice a day. As someone who enjoys winter, I hope he's right even though in most years that he's hyped a cold winter he hasn't done well. Here in the SE US and up into the Mid-Atlantic states, El Niño on average gives the best shot at a cold winter. One coming right after La Niña, especially more than one year's worth, probably helps even more. We're looking at a possible record breaking rise of the ONI from the prior year's La Niña low point, a huge shake up which I hope is a mechanism that leads to drastic changes in the upcoming winter vs last winter.

Euro landfalls in SE portion of Big Bend near 980 mb. It is significantly stronger and a bit further SE than recent runs. It then goes offshore 50 miles S of Savannah (mid-GA coast).

The average of the last 3 days of CFS runs for JFM isn't cold fwiw (I have no idea about snow as the maps don't show it). For hype purposes, he likes to post ONE run at a time when it has BN temps even though the CFS is a terrible model because that's how JB does things (just about all of us know this though): JFM precip: mainly near normal fwiw

Fwiw since the CFS is not a good model out just one month much less 4-6 months out, here's the CFS 2m temp anomaly (C) forecast for DJF based on the last 3 days/12 runs using 1984-2009 as base climo: (aside: Nino 3.4 SSTa peaks in Nov): Precip anomalies for DJF:

12Z UKMET: about same as 0Z with landfall NW part of FL Big Bend moving NNE followed by turn to NE/ENE going through south central and then SE GA. Then it goes offshore near CHS, SC: TROPICAL DEPRESSION 10L ANALYSED POSITION : 19.8N 86.1W ATCF IDENTIFIER : AL102023 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 27.08.2023 0 19.8N 86.1W 1003 24 0000UTC 28.08.2023 12 20.4N 85.3W 1001 29 1200UTC 28.08.2023 24 21.4N 85.5W 1001 33 0000UTC 29.08.2023 36 22.6N 85.8W 1001 36 1200UTC 29.08.2023 48 24.2N 86.1W 1000 34 0000UTC 30.08.2023 60 25.8N 85.5W 999 38 1200UTC 30.08.2023 72 28.6N 84.6W 995 49 0000UTC 31.08.2023 84 31.2N 82.7W 993 39 1200UTC 31.08.2023 96 33.2N 78.8W 993 43 0000UTC 01.09.2023 108 33.4N 75.0W 995 48 1200UTC 01.09.2023 120 33.8N 72.0W 999 46 0000UTC 02.09.2023 132 33.2N 69.2W 1001 43 1200UTC 02.09.2023 144 32.8N 68.4W 1003 37 0000UTC 03.09.2023 156 33.6N 65.9W 1003 35 1200UTC 03.09.2023 168 33.6N 64.5W 999 47

This is the strongest Euro yet as others were in low 990s at landfall and is very near the 0Z UKMET landfall point. This would be a big mess for the Big Bend wind-wise and especially storm surge-wise in this very vulnerable high poverty area as was discussed earlier ITT.

0Z UKMET: ~40 mile E shift at LF into NW FL Big Bend vs E Panhandle on 12Z run; once inland sharper turn to go offshore SC vs 12Z going over Augusta and then staying inland through SC into much of NC TROPICAL DEPRESSION 10L ANALYSED POSITION : 21.0N 85.5W ATCF IDENTIFIER : AL102023 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 27.08.2023 0 21.0N 85.5W 1004 25 1200UTC 27.08.2023 12 20.3N 85.6W 1002 27 0000UTC 28.08.2023 24 20.6N 85.3W 999 32 1200UTC 28.08.2023 36 21.7N 85.5W 999 35 0000UTC 29.08.2023 48 22.8N 85.5W 1000 38 1200UTC 29.08.2023 60 24.5N 85.6W 1000 41 0000UTC 30.08.2023 72 26.5N 85.3W 998 39 1200UTC 30.08.2023 84 29.2N 84.1W 995 45 0000UTC 31.08.2023 96 31.9N 81.8W 992 42 1200UTC 31.08.2023 108 33.6N 77.7W 991 43 0000UTC 01.09.2023 120 34.4N 73.4W 992 56 1200UTC 01.09.2023 132 34.4N 69.0W 996 52 0000UTC 02.09.2023 144 33.2N 65.7W 1000 45 1200UTC 02.09.2023 156 33.6N 63.2W 999 43 0000UTC 03.09.2023 168 33.5N 60.3W 997 48

I'm currently projecting an August ERSST 3.4 SSTa of ~+1.35. Looking at the 25 El Niño seasons since 1950, the average/median rise from Aug to peak month was 0.53/0.59 but the variation is huge from a mere .01 in 1987 and .06 in 2004 to a very large 1.09 in 1991, 1.17 in 2009, and 1.39 in 1982. To get a super ONI peak, I'd think that getting a single month peak of +2.15 would likely be enough. That would require a rise from Aug of 0.80. Only 6 of the 25 did that. Regardless, I'm expecting 2023 to be the 7th as of now based on strong model agreement. But we'll see.

DMIN

3.4 per OISST is now +1.6, which implies ERSST is likely +1.5+. It has warmed nearly 0.3 over just the last 9 days, the fastest warming since the rapid late May/early June warmup. Through June and July, combined, when the SOI averaged ~neutral much of the time, it warmed only 0.4. But Aug has already warmed 0.5 as the SOI (often a leading indicator) has been mainly negative the last 6 weeks. Based on this graph, Monday's update should be at +1.5. Aug MTD has risen to just over +1.3. With the recent rapid rise Aug OISST is headed toward ~+1.4, implying Aug ERSST of ~~+1.35. An Aug ERSST of +1.35 would make 2023 near 1957, just behind 1972's +1.40, and much warmer than 1982's +0.98 and especially 2009's mere +0.56. But it would be quite a bit cooler than 1965's +1.66 and especially 1997's/2015's +1.91/+1.93. So, Aug of 2023 looks to be near tied with 1957 for 4th warmest for ONI. Now, RONI is a different story.

12Z UKMET: similar to 0Z with landfall E FL Panhandle and then NE well inland in GA: so two runs in a row that are the furthest NW by a large margin NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 24 HOURS FORECAST POSITION AT T+ 24 : 20.8N 86.8W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 27.08.2023 24 20.8N 86.8W 1005 20 0000UTC 28.08.2023 36 20.8N 86.4W 1003 26 1200UTC 28.08.2023 48 21.7N 86.3W 1003 29 0000UTC 29.08.2023 60 23.1N 86.9W 1002 31 1200UTC 29.08.2023 72 24.2N 87.0W 1002 43 0000UTC 30.08.2023 84 26.1N 86.3W 999 36 1200UTC 30.08.2023 96 28.8N 84.8W 996 48 0000UTC 31.08.2023 108 31.6N 83.5W 994 36 1200UTC 31.08.2023 120 33.5N 81.8W 997 37 0000UTC 01.09.2023 132 34.6N 78.5W 1002 35 1200UTC 01.09.2023 144 36.7N 74.8W 1005 39 0000UTC 02.09.2023 156 35.9N 73.6W 1006 40 1200UTC 02.09.2023 168 36.6N 69.7W 1006 36

0Z UK: a whopping 150 miles W of the 12Z! Also, a little stronger. Comes into Fl Panhandle and then well inland in GA. This is easily the furthest west of any UK run yet: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 48 HOURS FORECAST POSITION AT T+ 48 : 21.1N 86.2W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 28.08.2023 48 21.1N 86.2W 1003 26 1200UTC 28.08.2023 60 22.2N 86.0W 1003 31 0000UTC 29.08.2023 72 23.6N 86.2W 1003 31 1200UTC 29.08.2023 84 25.6N 85.5W 1002 38 0000UTC 30.08.2023 96 28.3N 85.3W 999 36 1200UTC 30.08.2023 108 31.1N 83.7W 999 33 0000UTC 31.08.2023 120 32.9N 82.0W 996 32 1200UTC 31.08.2023 132 34.1N 79.4W 999 34 0000UTC 01.09.2023 144 33.9N 77.1W 1004 39 1200UTC 01.09.2023 156 33.1N 75.9W 1007 39 0000UTC 02.09.2023 168 32.2N 74.5W 1007 32

Ian formed in the C Caribbean and became a H way down below the Caymans 2.5 and a MH 1.5 days before SW FL landfall.

1. It isn't surprising to me that 1936 had the lowest dewpoints at Des Moines as that was during the heart of the Dust Bowl years and that July had the 3rd lowest rainfall of any during 1936-2023. The 1936 IA corn crop of 189 million bushels was by a good margin the smallest during 1936-2023 (see link). Decreased vegetation correlates well with not only hotter summer temperatures but also lower dewpoints (less evapotranspiration). The record heat and low dewpoints are naturally associated. IA Corn crop by year: https://beef2live.com/story-iowa-corn-production-year-85-205696 2. I've read a lot about the correlation between GW/CC and increased droughts. But related to GW/CC, dewpoints have increased significantly in recent decades in many places along with temperatures. I know they have here in the SE US, especially in summer. With that being the case, have relative humidities actually remained about the same? I'm asking this because the idea of increased droughts is as I understand it partially based on lower RHs due to hotter temperatures. But have RHs actually been dropping?

Indeed, the OHC is now pretty rapidly rebounding as I've been expecting. If I weren't expecting this rebound, I wouldn't have recently warmed my forecasted ONI to a super ONI peak (with 70% probability). It still needs to increase quite a bit more (preferably to well above the mid June high of +1.30 to +1.35) to give good support for a super ONI peak, but this is a significant start. So, the anomaly plunged ~0.60 C from mid June til ~July 20th. But over the last 30 days, it has risen 0.25 to 0.30 or nearly half of that prior 0.60 drop. I expect it to continue rebounding. If the warming rate of the last 30 days were to continue, it could get back to the mid June high as soon as late September. If so, there'd still be a two or so month long period for subsequent significant warming opportunities since OHC during a one year El Niño peaks on average in November (usually between Oct and Dec). That's when we could see this become quite impressive:

- This is now Invest 93L. - 12Z ICON 991 mb landfall (strongest run yet) in the Big Bend

12Z UKMET: track is SE of 0Z run but still landfalls near FL Big Bend; then moves NE to off the SE US; still a TS but a bit weaker than 0Z run due maybe to the further SE track (keep in mind UKMET is often conservatively low with winds): NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 84 HOURS FORECAST POSITION AT T+ 84 : 23.2N 85.4W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 29.08.2023 84 23.2N 85.4W 1005 31 1200UTC 29.08.2023 96 25.8N 83.9W 1002 38 0000UTC 30.08.2023 108 28.3N 82.7W 999 32 1200UTC 30.08.2023 120 31.7N 80.4W 1000 34 0000UTC 31.08.2023 132 32.8N 77.9W 1000 35 1200UTC 31.08.2023 144 33.9N 74.5W 1000 32 0000UTC 01.09.2023 156 34.3N 71.9W 1001 39 1200UTC 01.09.2023 168 34.2N 69.2W 1002 36