bdgwx

The convection allowing model runs last night showed a lot of promise especially the closer you get to St. Louis.

I'm tentatively planning on heading that direction as well. I'll make a final decision tomorrow morning though after looking at the satellite. Several of this evening's convection allowing model runs have been favorable even for a large portion of the MO path.

All things considered the GEFS ensemble mean doesn't look bad unless your target is Nebraska. I'm tentatively planning on heading south and east of St. Louis tomorrow morning. Based on the last several GEFS runs, HRRR, Euro, etc. I think the odds of finding clear sky increase as you get closer to KY and TN.

Probably a good idea. I think they're good for general trends and broad brush guesses, but at least with the GFS I think they look worse than they actually are. I don't track the cloud products from the RAP/HRRR (or any model for that matter) enough to really know how well they perform.

That's the incoming shortwave radiation. Nebraska is covered with clouds...at least on the experimental RAP. The southeast side of I-44 looks decent.

It's pretty obvious the experimental RAP has the eclipse modeled. It's my understanding that the 0Z run of experimental HRRR will run out to 48 hours this evening.

https://esrl.noaa.gov/gsd/eclipse2017/

Yes, the black oval is the position of the shadow. Keep in mind that the GFS cloud products look worse than they actually are. As an exercise take a look at GOES-16 imagery tomorrow and compare it to what these cloud charts are showing and you'll see what I mean.

I read that those interactive eclipse maps may be overestimating the size of the shadow by 100-1000 meters. The problem is that many scientists think the uun is actually slightly larger than the officially accepted value. One goal of the eclipse is to better narrow down the size of the sun. So the word of caution is that if you think you're just barely within the path you really might not be.

I'm still not sure where I'm going. Assuming clouds aren't an issue I will obviously stick close to St. Louis...just not sure if it will be north or south of the Missouri River yet. The St. Clair area is one I've considered. I'd be willing bet to most natives will either go west on I-44 or south on I-55. Interestingly, nearly the entire length of the I-70 corridor will be in the path. MoDOT has been advertising the eclipse on the dymaic message boards throughout the state, but you know there'll be truckers and other people who are completely oblivious to what's happening. I'm planning on avoiding organized gatherings as well. But, setting up in a random parking lot and taking it in with the rest of those there is fine if that's how it works out.

Absolutely. This is will likely be the most studied eclipse ever. I'm kind of curious what GOES-16 will show. Will we be able to make out the umbra shadow? Also, modeling is showing a pretty unstable airmass for much of the path so it'll be interesting to see what effect it has on cloud patterns and obviously the temperature too. One obscure research topic is the "eclipse bow wave" which is a form of gravity wave that lags the shadow by 15-30 minute and ripples out at several hundred mph. Will we be able to see these with GOES-16?

Here's the AFD from LSX this afternoon. Area Forecast Discussion National Weather Service Saint Louis MO 336 PM CDT Tue Aug 15 2017 [snip] .DISCUSSION FOR TOTAL SOLAR ECLIPSE... (Monday August 21st) The trend over the past 24 hours in medium-range NWP guidance is for the mid/upper level ridge across the southern CONUS to continue to build a bit northward through the day on Monday. This is a good trend for prospective viewers of the total solar eclipse passing through early Monday afternoon. Have lowered PoPs and sky cover a bit from yesterday`s forecast as the better chance of thunderstorms will be tied to the northern periphery of the ridge across the mid- Missouri Valley eastward toward the lower Great Lakes. However, some opaque cirrus blowoff from these storms to the north may be possible. In addition, there are numerous other mechanisms for the formation of clouds, many of which are very difficult to discern past 36-48 hours. That being said, current synoptic pattern forecast for Monday afternoon does look supportive of a partly cloudy to mostly sunny sky, with the most likely types of potential clouds being the aforementioned high-level cirrus blowoff from thunderstorms to the north/northwest of the area as well as diurnal cumulus. However, past total solar eclipses have noted that the cooling induced by the eclipse itself helps to reduce diurnal cumulus. Speaking of cooling, it certainly will be interesting to see exactly how much air temperatures are affected from the beginning to end of the eclipse. Attempted to add some detail in hourly temperatures by cooling readings several degrees nearest to totality (1800 UTC/100 PM) and 1-3 degrees in the hour immediately before and after during the partial phase of the eclipse. Actual temperatures nearest totality between ~1810 and ~1820 UTC will likely dip 5-15 degrees more, at least briefly.

12Z GEFS continues to trend slightly stronger and further northeast with upper and mid level ridge. I do wish it would slide further to the northeast though. For the St. Louis region I do have a concern with a possible MCS in NB having its cloud debris blown into MO by upper level winds, but if we could get that upper level anticyclone to move further north and east winds would blow more to the east instead of southeast nevermind that it would keep any shortwaves rippling through the flow further away to begin with.

FWIW the Euro looks better for MO. It has clear skies in the morning giving way to cumulus clouds in the afternoon. Research shows that the reduced solar radiation at the surface can slightly suppress convectively forced cumulus clouds (see here) so maybe that'll help this time too, I don't know. Regardless, be flexible. Right now official forecasts are more favorable the further southeast along the path you go so consider a drive more toward St. Louis if necessary. Keep in mind that traffic could be a problem especially along major interstates and near the St. Louis metro area.

Nebraska through Tennessee. South Carolina had higher cloud coverage.

12Z Euro has clear skies in the morning and then broad CU coverage in response to the unstable environment. Much of the eclipse path is under some pretty decent ridging so hopefully this trend continues.

I wish I could post it, but the 12Z Euro cloud cover products look favorable for most of the path except maybe closer to the East Coast. The EPS ensemble is favorable as well at least in regard to precipitation. It does show elevated rain chances along the East Coast portion of the eclipse.

I was wondering the same thing about NWP models. Do they model the loss of solar irradiance? I'm assuming they don't but I'm prepared to be wrong if someone knows for sure that they do. And yes, I read that a 5-15F drop is common. The temperature lags the irradiance by 15-30 minutes so the maximum effect will happen after totality.

For those planning on watching from Missouri keep in mind that MoDOT is warning motorists that there could be "massive" traffic problems. That was the word they used. Also, there are still some decent rooms available in the St. Louis metro area that are actually in the path. For example, hotels.com says there are rooms at I-270/I-44 for very reasonable rates. This is a very affluent area with lots of restaurants. And you'll get at least 90s of totality without even leaving the hotel parking lot. Elsewhere outside of the path availability is plentiful in STL.

By the way, it should be noted that many in this subforum will get the chance at another eclipse in 2024. That one goes through Indiana and will last 4 minutes. So while most people never get the opportunity to see an eclipse ever in their lifetime we'll all get two chances!

The partial phase lasts 3 hours so as long as you have eclipse glasses you'll be able to observe it for a long time. Also, based on what I've read once you've experienced one eclipse you'll want to do it again. It's also said that there is a night and day difference between being in the full shadow and the partial shadow...literally. So make sure you get to the full shadow.

The St. Louis NWS office says there is a 25-35% chance of clouds at 1pm and < 10% chance of rain on Aug. 21st based on climatological averages.

Lol. Head on over. I can't guarantee I'll be home, but you're all invited to hang out in the middle of the cul de sac.

I'm fortunate enough that my house is fully within the path of totality. I will see no less than 45s of totality even if I don't leave my driveway. I'm still considering driving deeper into the shadow path, but MoDOT is already warning people here to expect "massive" traffic problems so I don't know if it's worth it yet or not. From a scientific standpoint there are some interesting meteorological phenomenon that will be researched. This could (and probably will) be the most studied eclipse ever.

I'm with you guys. EPS, GEFS, and GEPS all have something significant brewing for late next week.