Total Solar Eclipse April 8, 2024 weather prospects

[Ben Holcomb]

The 12Z NAM really wants to put a tube or two down in the path of totality near I-20 to Waco. Geez, I wonder if I can pull off an eclipsenado? This is more stressful than I thought it'd be.

 

[Brett Roberts]

The 12Z NAM really wants to put a tube or two down in the path of totality near I-20 to Waco. Geez, I wonder if I can pull off an eclipsenado? This is more stressful than I thought it'd be.

I am fascinated by the impact of the eclipse itself on this setup. IIRC, GSL accounted for impact of the 2017 eclipse on solar radiation in their development version of HRRR at the time... @Jeff Duda, do you know if NCO's operational RAP/HRRR will do the same this time?

I don't believe any other operational NWP outside of HRRR/RAP is aware of the eclipse. My intuition is that a total eclipse could have quite a substantial impact on a classic dryline setup that is highly diurnally driven. We're taking a pretty big bite out of insolation for a couple hours near peak heating, even far outside the path of totality. Most likely, afternoon high temperatures will verify a hair cooler than non-eclipse-aware NWP suggests, even with full insolation returning by mid-late afternoon.

The actual setup in TX looks messier than a prototypical 6pm dryline, -40 J/kg MLCINH, conditional CI setup that could really get wrecked by an afternoon eclipse... but I actually think that makes it more interesting to watch in some ways. Is there a hypothetical setup where the early afternoon interruption to heating actually transforms it into a bigger deal because it prevents early upscale growth? That's probably a very narrow slice of the outcome space for all possible eclipse-severe interactions, and I doubt that's what we'll actually see Monday. But hey, at least this could be a nice distraction to focus on come Monday afternoon, when many of us who didn't splurge for last-minute New England flights may need one...

 

[Jeff Duda]

IIRC, GSL accounted for impact of the 2017 eclipse on solar radiation in their development version of HRRR at the time... @Jeff Duda, do you know if NCO's operational RAP/HRRR will do the same this time?

I don't believe any other operational NWP outside of HRRR/RAP is aware of the eclipse.

I confirm both of these statements. It should be fascinating watching HRRR forecasts roll in during this event!

 

[Dan Robinson]

I'm trying not to kid myself that we can actually have any confidence in cloud cover even the night before. We can't even get that right with most tornado setups (just look at the past 2 events this week, for crying out loud), what makes us think we can do it for the eclipse, haha. I think it's a done deal that I'll be heading to Pittsburgh tomorrow morning. Will be re-evaluating the situation from there. If need be, I can get back here on Sunday - but I'm expecting we'll have to bite the bullet and go northeast.

FWIW, 2017 dissipated nearly the entire Cu field within the path a few minutes before totality. I remember seeing model depictions of the temperature drop in 2017, but I can't remember which one it was.

 

[Ben Holcomb]

The actual setup in TX looks messier than a prototypical 6pm dryline, -40 J/kg MLCINH, conditional CI setup that could really get wrecked by an afternoon eclipse... but I actually think that makes it more interesting to watch in some ways. Is there a hypothetical setup where the early afternoon interruption to heating actually transforms it into a bigger deal because it prevents early upscale growth?

Unfortunately you're right - it looks messy. Interesting hypothesis, though. I will be interested to see how Monday's setup progresses. It'd be on my radar if there was not a total solar eclipse ongoing.

 

[JamesCaruso]

I don't believe any other operational NWP outside of HRRR/RAP is aware of the eclipse.

Look at this Thursday 4/4 12Z Canadian run. I remarked to myself how ironic it was that the only clouds from northeast TX to Indiana were in the eclipse path. And then I wondered, is the model influenced by the eclipse itself?? But the effect seems to be gone in more recent runs.

 

[John Farley]

Since I am committed to viewing the eclipse with family in the STL area, I am pretty much locked in to southern IL or southeast MO. There is a good bit of uncertainty there and could be right up to eclipse time, but the trend has been slightly better and it certainly looks better than some other areas. So I will take my chances. I remember in 2017 in Nebraska there was similar uncertainty, and a lot of cloud cover early in the morning, but it ended up working out fine, Tweaked my target a little east at the last minute then, but as it turned out I could have stuck with my original one, though that would have been stressful as it cleared there with 5 or 10 minutes to spare.

 

[Ben Holcomb]

@John Farley count me in the 2017 cloudy Nebraska gang. Got to clearing out west and had an excellent experience. I think I am still heading to the MO/AR/IL/TN area and hoping for the best.

The 21z RAP tonight is showing tornadoes in the bootheel/NE Arkansas near Blytheville on Sunday night. 2024 is wild, man.

 

[Jeff Duda]

Since I am committed to viewing the eclipse with family in the STL area, I am pretty much locked in to southern IL or southeast MO. There is a good bit of uncertainty there and could be right up to eclipse time, but the trend has been slightly better and it certainly looks better than some other areas. So I will take my chances. I remember in 2017 in Nebraska there was similar uncertainty, and a lot of cloud cover early in the morning, but it ended up working out fine, Tweaked my target a little east at the last minute then, but as it turned out I could have stuck with my original one, though that would have been stressful as it cleared there with 5 or 10 minutes to spare.

I just told my wife the odds of us leaving for S TX tomorrow are down to <1% after seeing the 00Z models come in. Everything I see just looks worse and worse for the area W of SAN, as I had been hoping for. New plan will be to head for Jefferson City Sunday and then down to SE MO (somewhere between Poplar Bluff and Jackson/Cape Girardeau) for the event. Odds are much more favorable for not-too-cloudy skies there.

I also remember the issue with the 2017 eclipse. I'll let excerpts from my write-up on the experience tell the rest of the story:

I had originally targeted the small town of Fairmont, Nebraska, about 60 miles to the southeast, and a bit closer to home than where I ended up. I abandoned the Fairmont target early in the morning after seeing consistent model forecasts of extensive cloud cover over especially southern and eastern Nebraska. I knew the disturbance causing the clouds was moving generally north and east, so I knew I was going to need to get further northwest than I initially planned to give myself the best chance of actually seeing the eclipsed sun during totality.
...
...
...

I made my Fairmont target before 10:00 AM, a clean three hours before totality; way too much cloudiness to the south. Little internal debate was required – I continued onward and jumped on I-80 at the York exit, heading west. Traffic had really dropped off once I crossed into Nebraska, and even in Fairmont there were few on the road. I did see several larger groups in roadside fairgrounds and open fields. Seems this is where the local townspeople decided to go. I suspect they had a disappointing show. Anyway, traffic on 80 was certainly busier than I would expect for a Monday morning, but everyone was still going 75-80 all the way to Grand Island. I briefly considered getting off at exit 318, as it was basically right along the center of the path of totality, and there was a break in the cirrus clouds at this location. However, I wasn't confident the break would last, so I kept going west.

I didn't want to bother with traffic within Grand Island, so I slipped by and eventually got off I-80 at exit 300 near Wood River. I meandered my way north towards Cairo, then dropped off the paved highway and explored the dirt road grid southwest of Cairo.

 

[JamesCaruso]

How proficient is the NAM with respect to cloud cover forecasts?

Which of the CAMs is generally considered best for same-day cloud cover forecasts?

 

[Dan Robinson]

One item I’ve been seeing from multiple sources is how the models’ cloud cover plots are not handling high-level cirrus well. The upper level RH plots indeed reveal a very different picture than the cloud cover plots. The 06z NAM for instance has high RH (presumably meaning cirrus of indeterminate thickness) over the entire northeastern US at 18z Monday.

The clearing that many models seem to agree on over the Midwest also includes a hole on the the 250mb RH. I’m not sure what to make of that as cirrus can presumably be thin enough or lower enough to not show well at 250mb.

This doesn’t do much for my already-shaky confidence levels.

 

[JamesCaruso]

Dan, the COD models page has cloud displays at individual levels, that may help correlate the RH with more-specific cloud interpretation. In the car on way to airport now so can’t really look.

 

[Bobby Little]

Im in a tight spot here! Headed to Florida for couple weeks from Michigan and debating on chasing Mon to Thurs..SORTA on the way there
Mich/Tx/La/Ms/Al/Fl. I realized now the eclipse event. My wife isn't real happy of the time and drive to Texas..and now she is unhappy about taking here to a area of cloud cover to miss the eclipse event. Couple that with the road network sun/mon and hotel prices, i think i am probably the most unsure/crazy/idiot than all of you here fretting. I wasn't even caring about the eclipse after seeing one in the 70s..but now more interested after all the hype the last couple days (and reading all you guys posts)....HMM MM decisions??
1. Head to Tx Mon. to stormchase..don't worry about eclipse. chase everyday (even in poor areas of Tx/La/Al/Fl) til Thurs.
2.Head out early Mon. along the center line trying to catch the eclipse on the way to Tx for the Tues.-Thurs. chase.
3.Drop down to Findley/Toledo (looks real good compared) for the eclipse Mon. and skip the storm chase period.
Not super confident about the tornado potential- any cloud openings in the Tx areas (eclipse)- poor chasing areas tue-thurs after looking at models
The clock is ticking...so is my wife.

 

[Sean Ramsey]

HRRR is about a run away from eclipse time but based on the 12z run it's looking pretty sad in the TX/AR corridor just as the long range models have been predicting for a while. I'm probably going to focus on chasing since four out of the next five days are chase opportunities (for me anyways) and let this eclipse go since I was there for the 2017 eclipse. Guessing it won't look much different this time so it's ok.

 

[JamesCaruso]

I love chasing but to me the 2017 eclipse was the single most awe inspiring moment of my life and would choose it over any tornado, especially since the next total eclipse in the US is 20 years from now.