Thursday, June 15, 2023

Unsettled Weather Lasts Into Early Next Week, Little Bit of a Break Tomorrow and Saturday

(Forecast)

Friday (High 87, Low 65): Partly cloudy. Isolated showers and thunderstorms are possible.

Saturday (High 89, Low 64): Partly to mostly sunny. An isolated shower or thunderstorm cannot be ruled out.

Father's Day (High 86, Low 65): Partly to mostly cloudy with numerous showers and thunderstorms possible throughout the day and night. Some storms may be strong, or even reach severe limits with damaging winds and large hail.

(Extended Outlook)

Juneteenth (High 84, Low 68): Mostly cloudy with a 50% chance of showers and thunderstorms.

Tuesday (High 85, Low 66): Partly to mostly cloudy with a 40% chance of showers and thunderstorms.

Wednesday (High 87, Low 66): Partly cloudy with a 30% chance of showers and thunderstorms.

Thursday (High 89, Low 65): Partly cloudy with a 20% chance of showers and thunderstorms.

(Tea Leaves Territory)

Friday (High 90, Low 67): Partly cloudy with a 20% chance of showers/thunderstorms.

Saturday (High 88, Low 68): Partly cloudy with a 30% chance of showers/thunderstorms.

Sunday (High 89, Low 68): Partly cloudy with a 20% chance of showers/thunderstorms. 

(Notes)

Here are some tips for staying safe from rip currents at the beach. It works a little different in real life than in the old Mario games. 

And the National Weather Service is still taking a survey as to how to best simplify their language in weather alerts. 

(Discussion)

It has been variably cloudy in the Tennessee Valley today, skies ranging from mostly cloudy to mostly sunny. There have been widely scattered thunderstorms, and a few have become severe with the ability to produce large hail or winds strong enough to damage trees and power lines. As I'm writing this at 6:46 PM we have a severe thunderstorm warning in effect for the Southwest corner of Cullman County. And I believe I saw one for Giles and Lawrence Counties up in Tennessee earlier today. 



And it has just been unusually busy for summer between today and yesterday. Not going to try to enumerate the various storm reports around here right now, will wait on damage surveys to be done later. And collect them if I have the time and energy. 





Winds have also been variable today. That strong upper Low has moved far into New England from the Great Lakes. We have good zonal westerly wind flow down around here, and we still have that front that won't go away draped over the Texas/Oklahoma border and stretching all the way down to about Dothan. 

The High was 81 in Cullman today with a morning Low of 66. I believe I forecasted 82/64, but it may have been 81/64. We did have some fog this morning I see, in the wee hours. Jasper saw a High of 84 today with a Low of 64 this morning. And Haleyville saw a High of 81, Low of 66. 




Doesn't look like that front will lift back Northward much until Saturday. 




Moisture is now looking so scarce around here tomorrow that I'm only putting in the minimal 20% chance of a summer shower or storm. Expecting a High about 87-88, Low about 64-65. 


Saturday looks the same, almost took out rain chances, but in this unsettled pattern and this time of year, keeping a 20% chance in looks reasonable. Looking for a High of 89-90 and again a Low about 64-65.



And the GFS continues to show the idea of a possible Mesoscale Convective System affecting our region on Sunday, Father's Day. The ECWMF and NAM are not as sold on this idea, but the GFS has done a better job with our local weather lately, and at 72 hours out, the NAM starts to lose reliability, almost always. So going to bring rain chance back up to a 50/50 shot, and if this develops as I think it will, that brings the chance for storms in that system to be strong, and even reach severe limits with damaging winds and some hail. Looking for a High in mid-80's, Low in mid-60's because of this pattern change where there should be more clouds and some rain keeping us from warming as much as previous two days. Usually an MCS will hit in afternoon or evening, but have seen them last into night hours before. 



The GFS pattern actually suggests it being more of a late evening/overnight deal. Which also could mean the storms will be weakening by the time they get to us. But here we are on Monday with still a 50% chance of rain. 


The ECMWF doesn't really pick up on the idea so much until we get into Monday. Which again makes me wonder if this will be more of a night-time deal. 


This map from the Storm Prediction Center shows a good outline of the likely track of the MCS if it develops as expected and moves East/Southeast through Sunday, Sunday night, into maybe early Monday. 

For Juneteenth I'm going to keep the rain chance at 50%, same as for Sunday, but expecting a High only in the lower 80's due to rain-cooling, and a Low in the upper 60's because of enough moisture overnight to prevent as much radiational cooling. 



Saw a forecast discussion that referred to this feature Tuesday and beyond as a "meandering" upper Low, and I think that's a great word choice. Will trim rain chance back to 40% and forecast a High in mid-80's, Low in mid-60's.



The GFS has us drying out for the most part Wednesday.


The ECMWF says not so fast, keeps us pretty wet. 

But I think they're both wrong and am going to continue to trend the forecast back toward seasonal climatology, a 30% rain chance, High in mid-to-upper-80's, Low in mid-60's.



Again on Thursday, American model trending very dry. 


While European model shows plenty of rain around. 

I think the GFS is closer to having it right and will trend again toward climatology. With that meandering Low, I don't see any reason to try to outguess what is most likely to happen this time of year based on conflicting model solutions. So I think we'll be back in the upper 80's by next Thursday, High in mid-to-upper-60's, only a 20% chance of rain. 



Now about once a week, I'll go ahead and try a 10-Day-Outlook, like some TV stations do. I think there is very little skill in these, including mine. But since it is summertime when the weather impacts around here are usually their lowest (except for the heat, when some people fail to use common sense), sometimes I find it fun. And if I had to guess, I'd say upper 80's, not sure we quite make 90 next Friday, upper 60's for the Low, a 20% rain chance. Not showing it here but the European model continues to keep us way too wet than makes sense in this overall pattern until we finally get some clearing by Sunday, but Friday and Saturday look wet on its 8-9 day outlook.



Then for Saturday, will bring rain chance up to 30% again since it is shown on modelling and we usually do get minor variations in the rain chance/temperature from one summer day to the next. High in upper 80's, Low in upper 60's. 



Then will bring rain chance back down to 20% for Sunday the 25th. Because of this look from the GFS. plus that's when the ECMWF gets off its mega-moisture-trip finally, that Sunday. (Which I don't think is correct. With all due respect to a great computer model. I don't think we'll have anywhere near that much rain beyond Monday of this coming week.) And also because it fits my personal experience of the local climate. We may approach 90 degrees again by this time. 

Having said all that, please understand that Days 8-10 of anybody's forecast, including mine, are notoriously unreliable. That's why when I include it in a forecast, I joke it off as reading tea leaves. It is challenging enough to forecast one week in advance, but I think the science has gotten pretty good at that. I consider it a challenge to try to have any skill beyond that time range, but also feel obliged to show my readers enough respect to be honest with them, that you can't really bank on it at such a time range. And yes, I do notice the tropical cyclone the GFS is showing at the end of the guidance I've shown here, but again, it is not reliable, that far out. Of course you'll watch any trend like that, just in case, but it is too soon to do much speculating. 


The National Hurricane Center gets paid to speculate on every minor tropical disturbance though. And there is a disorganized tropical wave moving off the West coast of Africa that is moving West/Northwest at about 15-20 miles per hour. Conditions are not favorable for it to develop right now, but they may become gradually more favorable as it moves across the Atlantic. And the National Hurricane Center gives it a 30% chance of becoming a tropical cyclone over the next seven days. That 0% chance you see in the graphic above is its chance of becoming a cyclone over the next 48 hours, two days. But if you go and read the text on their website, it could be a tropical cyclone within the next week, 30% chance of that. So that GFS guidance may be on to something, but we'll just have to wait and see. If you're really a nerd for hurricanes and tropical storms, you can look at all the tropical models and what they do with it. On this blog, I try to move away from hype. The regular news is tough enough to sort out now, with so much polarization and extremism, and a lot of journalists going rogue. When I was watching the drama between Johnny Depp and his ex-wife Amber Heard, the best information I got was from regular YouTubers, mainly a guy in the Carolinas with a channel called Southern Law. That guy is a real lawyer, while I'm only a guy who took about two years of college and then dropped out before I even got into calculus, but did get to take a couple of meteorology courses anyway. And have tried to learn a lot on my own. My forecasting or analyzing weather is more like some cousin or uncle you might have who plays the guitar or piano by ear. Someone like that still couldn't pick with Chet Atkins or be able to electrify a stage like Billy Corgan, or even Billy Joel. But since I do this sometimes and have a vague hope of going back to school to complete a meteorology degree some day, I try to give as balanced and accurate information as I know how. And the truth is, nobody knows what that tropical wave is going to do yet. The guidance from the NHC is as good as you are going to find anywhere. There are many tropical disturbances every season that never amount to anything, but of course, even the best scientists in this world (such as the ones at the Hurricane Center, they are awesome) have to watch each one carefully. This one has a low chance of long-term development, but it is a chance. 


There is another disorganized system a few hundred miles South of Baja California that is not expected to do anything. 

And computer model guidance has shown that another system may form South of Mexico this weekend. If it does, it'll bear watching over about the next week. If that one does develop, its movement would probably be to the West/Northwest. 


Back here on the home front, we could easily see another 2-3 inches of average rainfall totals over the next week, most of that coming on Sunday (Father's Day) and Monday (Juneteenth). 



And there is some concern for flash flooding issues between Sunday and Monday, along with the concern for strong storms capable of severe winds and/or hail. 


Thanks for reading. See you in the funny papers. 

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