Amelia Urquhart 🏳️‍⚧️

I work hard enough, I can give my code files silly names.

Hurricane Melissa's extreme Category 5 eyewall, rapid core disintegration over Jamaica, and subsequent rapid reintensification on approach to southeastern Cuba. Landfall is ongoing 20 mi/32 km west of Santiago de Cuba.

The clock has just about run out on Melissa’s restrengthening period as its eyewall approaches the Sierra Maestra mountains. Even though it’s still extremely dangerous, I’m happy to see it didn’t intensify as much as I feared it would.

Amelia Urquhart 🏳️‍⚧️ on X: "https://t.co/6y3EudFFTF" / X https://t.co/6y3EudFFTF

www.desmos.com/calculator/o...

(4/4) This inward motion may cause the surface low to fill in, and the cyclone would reach a new balance in the absence of other forces. However, if the pressure falls from ascent over the sfc low outpace pressure rises from sfc convergence, Melissa may restrengthen rapidly.

(3/4) Think of a figure skater, or a professor holding dumbbells standing on top of a spinning chair. As either one brings their arms in, they spin faster. We may observe a similar effect with Melissa.

(2/4) Right now, the pressure gradient force is trying to crush air inwards. Since the centrifugal force is weaker due to relatively slow winds, a net push inwards exists. This will encourage inwards motion and, through the conservation of angular momentum, strengthening of winds.

Melissa is quite far out of force balance after reemerging from Jamaica. The sea-level pressure gradient as measured by recon suggests a wind speed of 104 mph, but their dropsonde only measured 78 mph. This disequilibrium may encourage rapid restrengthening, see below. (1/4)

bsky.app/profile/amel...

I recommend anybody interested in donating uses the official website launched earlier today instead of the links I posted supportjamaica.gov.jm/donateq

American Red Cross: redcross.org/donate/donat...

American Friends of Jamaica: theafj.app.neoncrm.com/forms/afj-di...

World Central Kitchen: donate.wck.org/give/499865/...

International Medical Corps: internationalmedicalcorps.org?form=Melissa...

Category 5 Hurricane Melissa made landfall today near Black River, Jamaica with 185 mph winds and is currently re-emerging near Falmouth. If you have the means, I strongly encourage you to consider donating to a relief effort.

Direct Relief: donate.directrelief.org/give/647931#...

(more below)

Upper-level cutoff low, slightly chilly, 85 MUCAPE is my favorite weather outside of chasing

Comet A6 Lemmon has gotten everybody's attention lately, but did you know there's a second comet in the sky right now? On Friday night, C/2025 R2 (SWAN) was faint and has no discernible tail, but that only let its fuzzy green coma shine more clearly.

At the time of imaging, it was about magnitude 4.6. It has started to produce something of a dust tail, but it’s much less that C/2023 A3 (Tsuchinshan/ATLAS) last year and that’s keeping its brightness down. Through my 10x50 binoculars it looked like a faint colorless smudge.

Comet C/2025 A6 (Lemmon) near peak brightness on October 17!

(see replies for visual binocular view)

I took this shot this morning, from 5-7 AM with the full moon bearing down on me the whole time. I wasn't able to pull the faint tail out this time. In a way, that emphasizes the vivid green coma, a gravitationally unbound cloud of glowing gas emitted from the cometary nucleus.

Full loop of the Fujiwhara effect between hurricanes Humberto and Imelda up to the present! I plan to update this with the rest of Imelda's lifespan as it drifts out of frame in 3-7 days.

Veil Nebula (Caldwell 33/34, NGC 6960/6992) [True Color] - September 25, 2025

If I could pick one place from my travels to go back to tomorrow, it’d be Sonoma, California.

Sunset pictures on the side of the highway are self care in times like these

September 8, 2025 - Shattuck, Oklahoma

Yesterday wasn't just good for structure. It also had some great bolts after dark!

I love seeing the way the tail materializes out of thin air and the rush of the inflow into the stacked plates above.

While the contrast wasn't the best even with a lot of boosting, you can see the thin streaks of virga getting slung around the updraft.

Incredible structure yesterday in Laverne, Oklahoma!

- September 8, 2025

They could maybe unofficially do EF-ratable damage, but I have a hard time seeing any official surveys ever being done unless it has some serious consequences.

The fuck do you mean

Huge dust devil west of El Reno, Oklahoma at 3:25 PM CDT, just south of I-40 at mile markers 118-119 #okwx

August 24, 2025 - Reydon, Oklahoma

Watch the forward-flank downdraft come crashing down on my position

August 24, 2025 - Kelton, Texas