Saturday, June 17, 2023

Heavy Rain and More Storms Possible Tomorrow and Monday, Then Gradual Return To Typical Summer Pattern

(Forecast)

Father's Day (High 88, Low 64): Partly cloudy with scattered showers and thunderstorms possible during the day. Thunderstorms will become likely by the night hours, and some could be strong, with potential for gusty winds, hail, and heavy rainfall. 

Juneteenth (High 81, Low 66): Showers and thunderstorms likely. An isolated strong storm is possible, especially in the early morning. 

Tuesday (High 80, Low 65): Partly to mostly cloudy. Scattered showers and thunderstorms are possible.

(Extended Outlook)

Wednesday (High 82, Low 64): Partly cloudy with a 30% chance of showers/thunderstorms.

Thursday (High 84, Low 62): Partly cloudy with a 20% chance of showers/thunderstorms. 

Friday (High 83, Low 63): Partly cloudy with a 30% chance of showers/thunderstorms.

Saturday (High 84, Low 64): Partly cloudy with a 30% chance of showers/thunderstorms. 

(Tea Leaves Territory)

Sunday (High 85, Low 64): Partly cloudy with a 30% chance of showers/thunderstorms.

Monday (High 88, Low 66): Partly cloudy with a 20% chance of showers/thunderstorms.

Tuesday (High 90, Low 69): Partly cloudy with a 20% chance of showers/thunderstorms.

(Beach Forecast)

Sunday (High 88, Low 72): Thunderstorms likely. Dangerous rip currents and flooding possible.

Monday (High 89, Low 76): Thunderstorms likely. Hazardous rip currents possible.

Tuesday (High 89, Low 73): Showers and thunderstorms likely. Hazardous rip currents still possible.

(Notes)

Here are some tips on staying safe in rip currents, if you are headed to the beach any time soon. 

And I'm not posting about recent storm damage in Alabama or Tennessee until the local National Weather Service offices have had some time to catch their breath and compile an organized list of where all the damage or large hail occurred. There is plenty of time for that when the weather is quieter and more seasonable again. 

(Discussion)








It has been a mostly sunny day in the Tennessee Valley after some fog this morning. Winds have been light and variable, currently mainly from a Northerly or Northwesterly direction. The High in Cullman was 88, and the Low was 63. Jasper saw 90 degrees this afternoon after a morning Low of 64. Haleyville was the same as Cullman, High of 88, Low of 63. 

Fort Payne had a few more clouds today at the higher elevation, High 88, Low 63. Then on the other side of the state, Muscle Shoals cooked all the way up to 92 degrees after a Low this morning of 65. Decatur had a High of 90 and Low of 64. So seeing several places broke the 90-degree threshold today during our break from the rain. Huntsville was one of the places that got a little more cloud cover today, but still got a High of 92 there at the International Airport. Their Low this morning was 66. Gadsden also a hot spot, High of 90 degrees after a morning Low of 62. 

Birmingham saw a High of 90 after a morning Low of 67. Atlanta topped out at 89 after a Low of 69. Then up across the Tennessee border, Nashville had a High of 87 and Low of 65. Then looking at our smaller cities up in Tennessee, Winchester had a few more clouds today than most of us and was breezier at times, had a High of 86 and Low of 61. I notice that Fayetteville's visibility is down to 8 miles despite clear skies at the 6 o' clock hour, so I'm guessing haze. They had a High of 86, looks like, but many of their observations from this morning are missing from the list, so can't tell you what the Low was. Okay, checking an alternate source, MesoWest, it looks like their Remote Automatic Weather Station experienced some downtime this morning. Hey, stuff happens. The Birmingham radar at the Shelby County Airport went down a day or two ago, and their technicians already have it back up and running. Kudos to the people who help us all have excellent weather reports around here. Moving back to the West in Tennessee, Memphis had a High of 90 and Low of 70 today. And then glancing over in Mississippi, Tupelo had a High of 90 and Low of 69 today. 

So that is the trade-off, without these storms lately, we get the typical heat. And all this rain soaking into the soil here in June may help us out next month if we have some hotter times, like we usually do, keeps the heat from getting unbearable. 

That front is parked down around the Gulf Coast again, giving us a break from the rain and storms up this way today. 



Tomorrow and Monday, it will lift Northward again to bring us some chances for organized rain and thunderstorms. We will have to watch for thunderstorms at least flirting with severe limits with this, and potential for some localized flash flooding. Our severe weather season is over, but anomalies happen, and this unusually stormy pattern, I saw a couple of meteorologists (Dan Satterfield and Daryl Herzmann) suggest that this was about the weirdest pattern for June since the late 1990's, in about 25 years. I only saw that on social media so hope I'm not misquoting anyone, but I think it's safe to say, if you feel like the weather has been a little wacky lately, it is not your imagination. I personally found it strange to go straight from wildfires in Canada, which I believe were set by lightning, to enough rain we didn't have to worry about it affecting air quality. And then we had some wind damage around here and some epic hailstones over in Mississippi mainly. 



Tomorrow it still looks like a pattern is setting up for a potential mesoscale convective system to affect the Southeast region. We get those moving in here from the Northwest in the summertime sometimes. 


The timing has trended more toward it being an overnight thing, so that might help us luck out as to how strong the storms end up being. 



The most likely track of this MCS takes it through West-Central, Southwest, and South-Central Alabama too. Our chance of having any storms reach severe limits, doing wind damage or producing large hail in North Alabama or into any Southern Tennessee counties is a very low, marginal risk. 

Still worth keeping a mention of strong storm potential in the forecast, as well as heavy rain that could lead to at least isolated instances of flash flooding, since we've had so many rounds of rain lately. More likely it'll be beneficial for most of us, but have to keep an eye on the local flooding potential just to be on the safe side. 



Then on Monday as that system continues to work through the region, we'll still be covered up in rain through much of the day, a lot of us. I think a 40-50% rain chance is best for tomorrow, may go with 40% during the day, but definitely increasing rain chances to 60%, "likely" category, for the night hours and then as we get into Monday more like 70-80% rain chance. It is a close call because tomorrow, we may see sunshine for most of the day. Expecting a High around 88, morning Low probably 64 or 63 again. The rain may hold off until the evening and night hours with that MCS. Then for Monday, looking at a High closer to 80, Low in mid/upper 60's. 




Then we'll be dealing with a meandering cutoff Low on Tuesday, with its position bringing us Northwest wind flow aloft. Some other forecaster the other day deserves credit for describing this feature as "meandering". I didn't come up with that on my own. But that's what it really looks like as you go through guidance. 


And I hope that button I pushed just realigned the text properly. Yes, it did. 

Tuesday should feature a High of about 80, Low in the mid-60's, and 40-50% rain chance. I'll adjust the percentages after I've gone through each day and taken a look at the overall pattern. But it looks like after Monday, we are gradually trending back toward a more typical summer pattern of only scattered or isolated rain/storm chances each day and more seasonable temperatures (like we got today).




Then on Wednesday the rain chances should come down another notch, more like 30-40%. I will say that the GFS is starting to come closer to the wetter look at the ECMWF was showing a few days ago. Even though I thought it was a rare case of the European model being the one smoking too much of that CBD stuff. Quick aside, I had a relative taking that for pain who used about ten times as much oil as the bottle said to. Such states of mind have brought us a lot of good music but are definitely not the best for hard-nosed, scientific thinking. So when a computer model seems way off in la-la land from the reality I see happening, I often joke, what is it smoking? So anyway, Wednesday's temperature should warm slightly in the lower 80's, the Low in the mid-60's or perhaps edging back toward lower 60's. It is a close call how much to scale back rain chances and adjust temperatures with this "meandering" Low in the region each day. But the basic idea is there. 



And I still think this is a case where the American guidance beats the European guidance. I'm looking at the ECMWF alongside the GFS even though I'm not showing the European model graphics here. I don't think they have it right. Usually it is an excellent model; a graduate student/lab instructor, who thought I'd never seen it, told me it was "sick". And I remember it doing better than any other global models with some tropical system in the past, particularly Hurricane Sandy in 2012. But I do not think handling routine summer convection in our part of the world is its strong point. The GFS looks much more reasonable, bringing us some rain chances, but lower ones. Here for Thursday I think 20-30% rain chance is reasonable. And by this time, may see a High still in lower 80's but think the Low will be back down into lower 60's. 



By Friday it looks like that Meandering Upper Low will retreat into the Mid-South region and open up into a trough. And we will have wind flow coming in here more from the Southeast, which will increase our rain chances a notch. So if rain chances got down to 20% for Thursday, will increase back to 30% for Friday. Like I say, with this pattern, I'm going to carefully reevaluate the rain chance for each day after looking back over the overall pattern through the week. Try to get it as close to accurate as possible for sort of an odd weather pattern this time of year, which is trying to get back to a more typical pattern you'd expect this time of year. So the High should still be in the lower 80's, Low roughly in the mid-60's.



And will keep the higher rain chance for Saturday, not sure if I will bump it up another notch or not, may defer to climatology instead and keep it same as Friday's. I don't think the European guidance was totally wrong for this, think it was picking up on a trend of definitely rain chances each day, but took it too far. The American model has started to pick up on the same idea. So once again, this may keep temperatures down in lower 80's for Highs. With a Low in the mid-60's. 

So our return to more typical summer weather may be more gradual after all. And if we do get plenty of rain before July, that might keep us out of excessive heat like we have some years. The rain stays in the ground, and it helps when there's nothing but sunlight hitting the ground for a while some years. 



Looking beyond a reasonable forecast period into the land of tea-leaf reading, the pattern stays about the same on Sunday of the following week. 



We do see a heat bubble spreading across Texas by Monday the 26th. May trend our rain chances downward and temperature up slightly, but at least isolated rain chances stay in then. 

Important to notice: The GFS now is tracking that potential tropical cyclone way North of where it was just a couple days ago. That's why I was pointing out: You can't put much stock in these rogue tropical scenarios a week (or more) ahead of time. It is only one model's opinion anyway. These projections at this time range can change like the wind. 

I saw a guy on Twitter write something like, "DON'T LOOK AT THE GFS FOR THIS TROPICAL SYSTEM A WEEK FROM NOW!" If I had marked it, I would embed that tweet here, but I've lost track of it. And some people actually take that crap seriously. I'll get to the serious (sensible) level of concern for that tropical system in just a bit. 



Okay so on Tuesday June 27, if we can put any stock in these model trends this far out, it looks a lot like today was, back to minimal rain chances, mostly sunshine and some typical summer heat, about 90 degrees. 

This forecast has some tricky nuances, especially considering the model guidance picking up on a good general idea, but I don't think either global model has it quite right. So I've talked it out, now I'll go back through and consider the overall pattern carefully as I write the forecast for each day above. And I guess I'll throw in some "tea leaf reading", but please understand, it is just for fun, not meant to be taken that seriously, and I'm practicing it in the summertime just to see if any skill is actually possible. Like how close can I get to making that a believable part of any forecast that someone can rely on. One of the TV stations trying this 10-Day Forecast stuff actually tries to give specific temperatures for the 8-10 day range. The other I noticed doing it makes the last three days (8, 9, 10) separate so that it's clear it only shows a general trend. I'll try for exact temperatures and rain chances, just to see if I can luck out and get any accuracy at all, since summer is the most predictable season usually. Hopefully nobody takes it too seriously, and even if they do, it's not like the forecast for that time period is what you'd call high-impact. 


Now looking at the tropics in a realistic, not an alarmist way, that tropical wave several hundred miles Southwest of the Cabo Verde Islands is beginning to look a lot more organized, and it is likely that it will become a tropical cyclone within the next two or three days. The waters of the Atlantic look favorable to sustain it. As far as where it will end up, let me keep it simple for you: Nobody knows where this thing is going yet. Its current movement is to the West at 15-20 miles per hour. 


That second tropical disturbance did form, like models suggested, South-Southwest of the Mexican coast, several hundred miles away from land, and it moving W/NW at 10 mph. It may develop slowly, but by middle of next week, should move into less favorable waters. And if I had to guess, it will dissipate then. 





We will have to watch for excessive rainfall, maybe some flooding issues here, especially tomorrow and tomorrow night. Even if that only happens in one or two isolated places, it is a problem for whoever it happens to. Almost all flood-related deaths around here happen from people crossing water that covers a roadway or a bridge. So as they say: Turn around, don't drown. Just in case we do have any issues like that.

The severe weather risk here is minimal tomorrow/tomorrow night, but in case you should get a Severe Thunderstorm Warning, the best place to be is in a small central room (or hallway) on the lowest floor of a sturdy house. It is better if you can be in a sturdy house or other building anchored to the ground, rather than a mobile home. And at minimum, wherever you are, try to stay away from windows and anything that can easily conduct electricity. Some of this may be common-sense advice, but modern life can tend to be rushed, so these reminders can help sometimes. 


Average rainfall totals will probably be another couple inches for most of us, the higher totals of about 3 inches more likely over Northeast Alabama up into Southeastern Tennessee. And much of Georgia, the Carolinas, down into Florida, may also see more rain like that. But some of the heavier storms tomorrow or tomorrow night may produce localized flash flooding, and we really can't pinpoint exactly where that will happens, if it does. Just know the potential is there. 


P.S. As of 8:24 PM, adding mention of heavy rainfall potential to forecast for tomorrow because I just forgot to put it in there, after saying a lot about it in the discussion part. Sometimes I read back through to try to catch mistakes, and this was a mistake. 

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