Thursday, August 10, 2023

Drier, Milder Air Possible Next Week

(Forecast)

Friday (High 88, Low 70): Partly cloudy. Widely scattered showers and thunderstorms are possible.

Saturday (High 90, Low 70): Partly cloudy. Isolated showers and thunderstorms are possible. 

Sunday (High 92, Low 71): Partly cloudy. Isolated showers and thunderstorms are possible.

(Extended Outlook)

Monday (High 91, Low 71): Partly cloudy with a 30% chance of showers/thunderstorms. 

Tuesday (High 87, Low 69): Partly to mostly sunny. 

Wednesday (High 86, Low 64): Mostly sunny. 

Thursday (High 88, Low 66): Partly to mostly sunny with a 20% chance of a passing shower or thunderstorm. 

(Tea Leaves Territory)

Friday August 18th (High 90, Low 68): Partly cloudy with a 20% chance of showers/thunderstorms.

Saturday August 19th (High 89, Low 69): Partly cloudy with a 30% chance of showers/thunderstorms. 

Sunday August 20th (High 90, Low 70): Partly cloudy with a 30% chance of showers/thunderstorms. 

(Beach Forecast)

Friday (High 93, Low 82): Partly cloudy, hot and humid. Isolated showers and thunderstorms are possible.

Saturday (High 94, Low 81): Partly cloudy and seasonably hot. Widely scattered showers and thunderstorms are possible. 

Sunday (High 94, Low 80): Partly cloudy and seasonably hot. Widely scattered showers and thunderstorms are possible. 

(Pronóstico)

Viernes (Alta 88, Baja 70): Parcialmente nublado. Es posible que haya lluvias y tormentas dispersas.

Sábado (Alta 90, Baja 70): Parcialmente nublado. Posibles lluvias y tormentas aisladas.

Domingo (Alta 92, Baja 71): Parcialmente nublado. Posibles lluvias y tormentas aisladas.

(Perspectiva extendida)

Lunes (Alta 91, Baja 71): Parcialmente nublado con un 30% de probabilidad de lluvias/tormentas eléctricas.

Martes (Alta 87, Baja 69): Parcialmente a mayormente soleado.

Miércoles (Alta 86, Baja 64): Mayormente soleado.

Jueves (Alto 88, Bajo 66): Parcialmente a mayormente soleado con un 20% de probabilidad de una lluvia pasajera o tormenta eléctrica.

(Territorio de las hojas de té)

Viernes 18 de agosto (Alta 90, Baja 68): Parcialmente nublado con un 20% de probabilidad de lluvias/tormentas eléctricas.

Sábado 19 de agosto (Alta 89, Baja 69): Parcialmente nublado con un 30% de probabilidad de lluvias/tormentas eléctricas.

Domingo 20 de agosto (Alta 90, Baja 70): Parcialmente nublado con un 30% de probabilidad de lluvias/tormentas eléctricas.

(Pronóstico de la playa)

Viernes (Alta 93, Baja 82): Parcialmente nublado, caliente y húmedo. Posibles lluvias y tormentas aisladas.

Sábado (Alta 94, Baja 81): Parcialmente nublado y caluroso según la estación. Es posible que haya lluvias y tormentas dispersas.

Domingo (Alta 94, Baja 80): Parcialmente nublado y caluroso según la estación. Es posible que haya lluvias y tormentas dispersas.

(Notes)


The National Weather Service in Birmingham posted a great explanation of why they don't issue a Tornado Warning for every single storm that rotates. Apparently they really dealt with the smart-aleck armchair meteorologists a lot during this latest severe weather threat. 

While the tropics are pretty quiet for now, NOAA does have a new hurricane forecast model to use this season. 

If you are headed to the beach, probably the only hazard you'll find beyond what you can handle by common sense is rip currents, so here is some information about how to stay safe if you encounter one. Seriously, I know someone who had two family members get caught in one off the California coast within the past year or so. One of them got out on her own, other one had to be saved by a lifeguard. 

If you'd like to learn more about the weather, the National Weather Service has a program called JetStream where you can learn for free at your own pace. They are jokingly calling it their back to school program. 

All of the National Weather Service offices that serve Tennessee (so I believe that is Nashville, Memphis, Morristown, and Huntsville) have gotten together to make weather preparedness information available both in English and in Spanish. That's one reason I've started trying weather forecasts in Spanish sometimes. A lot of Hispanics live around here now, and while they are usually more adept at learning English than Gringos are at learning Spanish, it might be nice to hear it in your own language. It is kind of tiring to do it in a weather forecast, but in the long-term, I'd like to get back to learning the language, since I was always good at it in school, and I like the way it flows off the tongue. Plus as much Mexican food as I eat, it's a wonder I'm not 50 pounds fatter than I already am, and I might as well enjoy some of the language as well as the yummies. If I'm remembering right, they consider things like tacos to be snacks in Mexico, and authentic food there has more of a variety. I still like making homemade burritos though. And actually the simple kind I've started making are not all that fattening, but are still good. Not much more to them than mashed-up pinto beans. Unfortunately for the Spanish forecasts, I often get lazy and use Google Translate, and then just check it for mistakes. And I used to write parts of my school assignments in Spanish in the third grade. So I've slipped a bit. Unless it is a waste of energy, perhaps I should practice and get this skill back. If anybody has feedback on the Spanish experiments, please leave me a comment. I will be glad to fix any mistakes. Since I have not heard anything about them, I don't know if anyone finds them useful or not. But about once a week, if I have time to do a weather forecast, will probably still try them. 

(Discussion)


We had some rain and thunderstorms early today in the Tennessee Valley, with a clearing trend as the day went on, the sun breaking out by afternoon. The High in Cullman was 84 with a Low of 66. Jasper saw a High of 86, Low of 68. Haleyville is still overcast at this hour (5 PM) but has had periods of the sun breaking out earlier in the day, had a High of 83 and Low of 66. Fort Payne got up to 85 degrees after a morning Low of 68. Decatur got up to 84 degrees, Low of 68. Huntsville saw a High of 84 also after a Low of 68. Up across the Tennessee state line, Fayetteville saw a High of 82 after a Low of 66. Savannah in Hardin County has stayed pretty cloudy today, High of 79 and Low of 70, more moisture lingering up that way. Nashville had a High of 83 and Low of 70. Muscle Shoals saw a High of 85, Low of 69. Over across the Mississippi state line, Corinth saw a High of 79, Low of 68. Tupelo has also stayed overcast most of the day, High of 84, Low of 69 there. 



The front is now hugging the Tennessee/Kentucky state line. To some extent, the pattern of it waffling around through the region will continue until about Tuesday, but even with that, our weather trends drier even in the next few days. 



The GFS really has us dry tomorrow. 


But I think the NAM is a little more realistic in this pattern. About a 30% chance of rain looks reasonable, which means widely scattered. And the High should get up to about 87-88, Low near 70. 


That dome of high pressure starts to expand into our region from out West on Saturday. 


A scenario that is supported by the NAM. 

So I'm going to reduce the rain chance to a minimal 20%, forecast a High of about 90 or so, Low near 70 again. 

By the way, not expecting any sort of organized severe thunderstorms with any of this. We can always see summer thunderstorms that pulse up randomly and briefly produce strong winds or some hail, sometimes enough to do some minor damage. The organized severe thunderstorms we've had lately were anomalous for this time of year. Although I do remember certain years like 2009 or 2011, where the summer got unusually stormy at times. Back then, I did not understand as much about weather as I do now, at least I hope I've learned some things along the way. If anybody gets a stronger storm over this weekend, it'll be one of those random "pulse" kind of storms that we see every summer, hit-or-miss. 


Sunday I don't think any model has it right, not the GFS shown here or the NAM or even the ECWMF. I'm just going with persistence and thinking about climatology. Forecasting a minimal 20% chance of rain again and a High in the lower 90's, Low in lower 70's, pretty close to 90/70 but at least the daytime High may rise a degree or two above that. 



And even though I'm showing the model output just for being thorough, they really don't do well with summer rain around here. The upper-air predictions might be a little better, just trying to predict the overall pattern shifts. We've still got pretty strong high pressure in the region. But I'm no longer seeing any reason from the GFS or the ECMWF to bump the rain chance up for Monday, so going to keep it at 20% after all. Temperatures similar from Saturday through Monday. 



Then on Tuesday it looks like the frontal boundary actually pushes through North Alabama and brings us some milder, drier air. Going to take rain chances out for Tuesday. The models have gotten this unlikely scenario right several times this season. So this time I am believing them over the local climatology. I guess the rain chances might ramp up a little Monday night, but that would really be nitpicking to give a 30% chance of rain for Monday night because of a front passing through, only a 20% chance during day Monday. For summer, that seems like too much nitpicking. Even other times of the year, we have fronts pass through that are mostly or all dry. Expecting a High in the upper 80's, Low near 70, maybe upper 60's already.



On Wednesday, high pressure behind that boundary remains in region, expecting mostly sunny skies, High may struggle to get out of the mid-80's with this shot of drier, milder air, Low in the mid-60's. Don't think we'll see lower 60's for most places. But the drier air will allow for pretty good radiational cooling overnight.



By Thursday I get skeptical of what the models are showing and think a 20% chance of rain should come back to the forecast. Still I doubt we quite back it back to 90 degrees, just upper 80's, with a Low just barely edging back toward the upper 60's. I will probably go with 66 for my estimate in the official forecast above. 



And just for fun, let's look beyond that, into the land of a farmer's almanac or reading tea leaves almost. Beyond about a week, models get notoriously unreliable, might show you general trends, but that's it. They will continue to gradually improve over time. Seven-day forecasts used to be a rare new thing. I'm mainly thumbing my nose at how a lot of forecasters now (in the broadcast world) like to try these 10-Day-Outlooks. And some of them try for specific temperatures even at that range instead of just giving a general idea. 

Playing along with such foolishness, this look for next Friday from the GFS doesn't really lead me to think anything other than another High in upper 80's, Low upper 60's day with a 20% chance of a shower or thunderstorm. 



It is showing a little extra moisture on Saturday the 19th, though it is mainly over South Alabama. Then again our upper-level winds are coming from the Gulf, so it is reasonable enough to bring the rain chance back to 30%. Which would likely keep the temperature from rebounding quite to 90 yet. Low might rebound to about 70 though. That seems reasonable, at least as reasonable as you can get in a 10-Day-Outlook. This is Day 9 of it. 



And it looks like we'll get even more Gulf moisture on Sunday if this guidance is right. But it has a hard time getting it right for summer convection even a few days in advance. Climatology usually beats the models. So I'm keeping the rain chance at 30%, High somewhere around 90, maybe still in upper 80's if we do get enough extra moisture to keep enough clouds and rain, keep the temperature from making 90 again, Low roughly around 70. And this is all with the understanding that there is very little skill in forecasting out to 10 days. This is my best shot at it. But I don't think even the best forecasters in the world get Days 8-10 right all that often, even in the summertime; and even then, it's by luck. I mean seriously, I'll be blunt: I looked at one of the TV station's 10-Day Forecast, and I do not know how in the world they came up with such a forecast for days 8 through 10. I only looked at one this time, but it sort of looks to me like they don't even care, and are just throwing that up there because they think it looks good. So I can't always resist lampooning this. And seeing if I can bring any skill at all to it. I'm not going to do any more damage than some of these broadcasters. And if I had to guess, it's probably some bigwig at the station forcing them to do a longer forecast to get better ratings. That individual forecaster may have no control over it, for all I know. I think it's really silly when you give your audience no indication of how dubious a forecast at that time range actually is. And one station, I will say I respect for doing exactly that, showing a distinction between the regular 7-Day-Forecast and that murky 8-10 Day period. If I'm going to post weather forecasts, I'm going to do it the way I believe is right. And part of that is pointing out when I think other people are doing something really wrong, even if they have more formal education and more real-world experience than I do. I think they also know that this is a less-than-ideal practice, but are doing it anyway. So . . . I make fun of it. While hoping that some day the science does get good enough to give a reliable forecast beyond a week in advance. As of right now, I think the accuracy drops off beyond even three days. Days 4-5 will be a little less accurate, but still pretty good most of the time. And then even by Days 6-7 you're looking more at a general trend. And then beyond that, a general trend is the best you can do. That's my opinion. In summertime, climatology sort of helps us out and makes it hard to mess up the forecast too bad, no matter how far out you try to go. 


In the tropics, things are quiet in the Atlantic. But in the Pacific, we have Hurricane Dora, which missed the Hawaiian Islands by several hundred miles. But they still got some wind gusts along with dry conditions, which sure didn't help the wildfire danger in Maui

That weak wave behind Dora is about 2,000 miles Southeast of Hilo, Hawaii and is producing showers and thunderstorms, but they are disorganized. It will drift West at about 10-15 mph and is not going to do anything this weekend, but has a low chance of gradual development next week. 



Hurricane Dora is well away from any land now but is still a major hurricane and going to weaken very slowly as it moves West/Northwest over the next five days. Winds are sustained at 120 miles per hour. Of course they have to keep any ships away from it, but this hurricane did not hit any land. I started to say that was a good thing, but I'm not sure the wildfires in Maui are any better than a major hurricane making landfall would have been. They sure are lovely to see on the satellite images from outer space. 


There is a tropical wave producing disorganized showers and storms several hundred miles Southwest of the coast of Southwestern Mexico. It is moving West at 15 mph and likely to turn into a tropical depression by early next week. 

Another wave is located well to the Southwest of the tip of the Baja California Peninsula and is also producing disorganized showers and thunderstorms. It is moving West at 10-15 mph and might develop very slowly over about the next week, but overall the chance of it becoming a tropical cyclone in those waters is looking kind of low. 


Rainfall totals for this forecast period are expecting to be light on average. Of course any time in summer, someone can randomly get a shower or thunderstorm in the heat and humidity that produces locally heavy rainfall. Even on days with no rain in the forecast, in the summertime, sometimes you can still get a random surprise. It's just the local climate. But for the most part, we'll see rainfall totals under a half-inch for this forecast period. And those extra three days at the end don't count, I mean for the real forecast that goes out seven days. 



There were numerous reports of wind damage yesterday, and we've just had a lot of wind damage in our region on several different days lately. I have not yet seen storm surveys of them. I imagine the Weather Service staff hasn't had much time to go and survey one day's damage before the next round of storms came in. The storms have felt relentless this week. I did just see where the Birmingham office completed a survey of some damage in Etowah County from August 3rd. I'm glad the pattern is finally going to change. Much of next week looks pretty nice if the heat or the storms have been preventing you from getting stuff done outside. 

After a lot of hem-hawing back and forth, I finally decided on a 30% instead of 20% chance of rain for Monday just based on past days' model runs and the overall pattern. Usually we do have some increase in rain chance before a front passes through, especially this time of year, when most fronts are going to wash out instead of actually passing to our South. The uptick in coverage of rain on the radar might not happen until the evening/night hours anyway. But this time of year, most days carry a 20-30% chance of rain anyway. The days it looks more likely, you forecast 30% usually. The higher rain chances we've had for a lot of this summer are unusual. At least to have so many rounds of it. Most summers, it is an occasional thing that breaks the monotony. 

And for the "tea leaves" section, I went with a couple 90-degree days after all. Especially at that time range, if you're going to try it at all, makes more sense to trust climatology than the models. 

I took some time to correct the Spanish as much as I know how. But I still wonder if there is a better way to say "widely scattered showers" than "lluvias dispersas", which means "scattered rain showers". Any native speakers, if you come across this, I'd appreciate knowing how to better communicate that this is a 30% chance of rain and not a 40% chance. That the showers are a little more scattered than if I just said "scattered showers" in Spanish. 

This may be a waste of time, but hey, some people waste the same time playing video games, which gets a lot more expensive than this. So . . . what the hell . . . why not? 

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