GaWx

It’s surprising that the Arctic is blue. Do you know why?

For the first time this season, the latest UKMET (12Z) has a TC in the MDR (moving WNW): NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 120 HOURS FORECAST POSITION AT T+120 : 10.3N 40.8W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 06.08.2025 120 10.3N 40.8W 1013 25 0000UTC 07.08.2025 132 11.4N 42.4W 1012 25 1200UTC 07.08.2025 144 13.0N 44.1W 1012 26 0000UTC 08.08.2025 156 14.8N 46.7W 1012 28 1200UTC 08.08.2025 168 16.1N 50.7W 1011 27

Please post your August of 2025 observations as well as other current or recent conditions at any location. At the end of this month, met. autumn will finally be here! Also, this is per climo the first of the 3 most active months tropically speaking. Hopefully, we have a much calmer season around these parts than the devastating 24! If any moderator sees this, please pin this and unpin the July ‘25 obs thread.

I had 8.25” of rainfall in July. That’s a bit above the July climo average of ~6-7” for the area. Most of this fell just during July 9-13, during which I had moderate flooding in my garage as well as some water splashing under the door and into my foyer. The hottest I saw on my thermometer was 98.7.

August ACE forecast: Today’s Euro Weeklies vs yesterday’s (using 2005-24 base) 8/4-10: 0.9 vs 0.8 8/11-17: 1.5 vs 1.9 8/18-24: 1.6 vs 2.1 8/25-31: 1.2 vs 1.1 Overall, I’d call this slightly less active than yesterday’s run but still a good bit more active than 2005-24 average ACE for August as a whole.

For the 2nd run in a row, the UKMET (12Z) has a TD from off the SE US from a frontal zone with no notable strengthening and with very slow movement. This run has it initially moving NE/NNE before turning to the WSW and then SW a couple hundred miles off NC: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 66 HOURS FORECAST POSITION AT T+ 66 : 32.9N 73.5W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 03.08.2025 72 32.7N 72.9W 1010 26 0000UTC 04.08.2025 84 33.1N 71.9W 1009 26 1200UTC 04.08.2025 96 33.9N 70.8W 1010 29 0000UTC 05.08.2025 108 34.3N 70.4W 1012 27 1200UTC 05.08.2025 120 35.1N 69.4W 1014 30 0000UTC 06.08.2025 132 35.8N 69.2W 1014 31 1200UTC 06.08.2025 144 36.4N 69.1W 1015 30 0000UTC 07.08.2025 156 36.0N 69.8W 1015 31 1200UTC 07.08.2025 168 35.5N 70.4W 1016 29

The UKMET is back to having a TD form on the 0Z. But unlike yesterday’s 0Z, which developed the current central MDR wave that was moving NNW to threaten the SE US, this one forms on an old front just off the SE US coast. After forming, it crawls NNE to just offshore the Mid-Atlantic coast remaining as a TD: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 90 HOURS FORECAST POSITION AT T+ 90 : 32.0N 75.3W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 04.08.2025 96 31.4N 75.7W 1010 29 1200UTC 04.08.2025 108 32.1N 74.8W 1012 25 0000UTC 05.08.2025 120 32.1N 75.0W 1013 25 1200UTC 05.08.2025 132 33.1N 73.9W 1015 23 0000UTC 06.08.2025 144 34.3N 73.9W 1015 23 1200UTC 06.08.2025 156 35.7N 73.6W 1014 30 0000UTC 07.08.2025 168 37.6N 73.0W 1012 28 *Edit: 0Z Euro is a bit similar to 0Z UKMET but with just a very weak sfc low rather than a TD. It similarly goes up the US E coast just offshore and toward Cape Cod and Maine.

Though 8/4-10 dropped likely partially related to little support for the current MDR AEW, today’s Euro Weeklies are slightly more ominous than yesterday’s for August’s ACE as a whole: % of 2005-24 averages: 8/4-10: 80% (slightly lower than yest.) 8/11-17: 190% (slightly higher than yest.) 8/18-24: 210% (much higher than yest.) 8/25-31: 110% (same as yest.) Taken as a whole, these probably imply a prog of ~38 ACE for next month fwiw. Please don’t shoot the innocent messenger!

Good news regarding microwave scans:

Followup: Unlike the 0Z, the 12Z UKMET has no TD.

For those who don’t realize this, the Midwest and just downwind have been helped high tempwise in recent decades by larger crops holding in soil moisture better and raising RH. These larger crops have partially been due to CC, itself. But lows haven’t been helped by this.

The reason I said I was only getting “slightly concerned” in deference to the UKMET usually being conservative is that the 0Z UKMET is the only major 18Z/0Z (and I can now say 6Z for that matter) global with anything even close to a TD from this. Also, recent GFS/Euro/CMC ensemble runs have had almost nothing. Earlier UK runs had only a disturbance though distinct. One has to go back to yesterday’s 12Z CMC/JMA/ICON to find something close to a TD on any other global run from this.

0Z UKMET fwiw has TCG/a TD at 168 in the far NW Bahamas: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 168 HOURS FORECAST POSITION AT T+168 : 26.9N 78.3W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 06.08.2025 168 26.9N 78.3W 1014 27 ———— I’m getting slightly concerned with this as it’s coming from a currently active AEW that’s now in the E ATL based on what I’m seeing on the 0Z and earlier runs of the UKMET. The 0Z has this AEW move to the N Leewards vicinity at 96 and then form the TD at 168 in the far NW Bahamas. It is then recurving NNW around a strengthening Bermuda high and threatening the SE US mid to late next week with no sharp upper trough to allow a sharp enough recurve to protect the coast. I looked back and found a WNW moving distinct disturbance from this same E ATL AEW as far back as the 0Z 7/27 UKMET run.

My rough estimate of ACE progged by today’s (7/29/25) Euro Weeklies: Aug 4-10: 3 Aug 11-17: 8 Aug 18-24: 11-12 Aug 25-31: 13-14 These 4 weeks would add to ~36, meaning a notably more active than active era normal for August should today’s EW verify closely. Since the active era began, only 6 Augusts (1995-6, 1998-2000, and 2004) had significantly >36 ACE, while 18 had significantly <36. That leaves 6 Augusts fairly close to 36 (say 31-41): 2005, 2007, 2010, 2012, 2021, and 2023. After those 6 Augusts, how was each Sept vs 1995-2024 climo? 2005, 2010, 2021, and 2023 were active while 2007 was inactive and 2012 was near avg. How were the Octs? 2005, 2010, and 2012 were above avg while 2021 and 2023 were near avg and 2007 was quiet. Other than hoping for another 2007, this isn’t encouraging for someone who wants an inactive season, especially considering the progged weak La Niña per RONI.

Chance for record low monthly NOAA PDO increasing for July. Current record is -3.8. It’s possible it will even end up just below -4:

Charlotte just tied the hottest 4 day period on record back to 1878!

Per Eric Webb, 1880-1 was a classic cold weak El Niño. 1881-2 was neutral: https://www.webberweather.com/ensemble-oceanic-nino-index.html

I won’t be getting anything like that but I’d welcome any cooldown of consequence to closer to normal!

There’s a sudden popup heavy thunderstorm that just formed only a couple of miles from me. It’s hard to tell whether or not it will spread out or generate others nearby to give me rain. The other possibility is for it to move toward me although I’m leaning against that right now based on subtle hints and H5 model progs suggesting it might move to the E. Regardless, steering winds are very light and flash flooding is a concern for wherever it lingers. 1:20 PM update: initial cell drifted away but it lead to more developing including at my location. Temp plunged from 92 to 80 within just a few minutes in the rain! 3:30PM update: I received only ~0.05”. Temp rose back some but only to 82 thus far.

KSAV today had a high of 100. That’s the first 100+ since 6/23/22 and the first 100+ in July since 2019. The HI peaked at 112. I don’t know what my high was but it was at least 98.

At 10AM today, Tampa is 2 F cooler than 24 hours ago and the wind is light from the S instead of from the seabreeze pinning rare N. Both of those along with climo point to very little chance of another 100 F high there today. @bluewave

I’m not Chris, but I already know the answer because I followed it closely. Tampa tied Jacksonville, Gainesville, and Leesburg for the hottest of major FL reporting stations yesterday with 100. This tied a daily record at JAX and was easily a new daily record at Leesburg. Lessburg’s tied with 1990 for a monthly record, but July records go back only to 1959. Orlando was “only” 97. Edit: it’s interesting that Tampa was tied for the hottest in FL yesterday despite being one of only very few stations in FL having not hit 100 before yesterday. It took just the right (or wrong) wind (a very rare for July light NE wind to keep the seabreeze away) along with few or no clouds to make it happen as the tweet Chris quoted mentioned. Even a strong NE wind likely wouldn’t have allowed it because that would bring in too much cooling over from the Atlantic side.

Based on hourlies, it’s possible that either or both of Augusta and Columbia had lows of 80. If so (we should know later this morning) and if convection doesn’t bring lower temps than 80 the rest of today, this would mean: -at Augusta (Bush) it would tie the warmest low for any date since 1945 and would be the warmest July low since 80 in 1990 -at CAE it would tie for the warmest July low since 1893 Edit: CAE’s lowest this morning was, indeed, 80. Let’s see whether or not later convection at or near there cools it to below 80 before midnight. But Augusta’s low turned out to be 78.

Jacksonville (tied daily record), Hogtown, and Leesburg (new record for date) joined Tampa at 100 for yesterday’s high.

I adjust with the model consensus, with each model adjusted for what I perceive to be its bias. My latest prediction of a -0.4 ONI low was based on July runs. I’ll re-examine in August.