Tuesday, May 30, 2023

Pretty Typical Summer Pattern, Warming Trend Going Into Weekend

(Forecast)

Wednesday (High 83, Low 62): Partly cloudy. Widely scattered showers and thunderstorms are possible.

Thursday (High 83, Low 63): Partly cloudy. Widely scattered showers and thunderstorms are possible. 

Friday (High 86, Low 64): Partly to mostly sunny. Isolated showers and thunderstorms are still possible even as temperatures increase.

(Extended Outlook)

Saturday (High 89, Low 65): Mostly sunny.

Sunday High 88, Low 64): Partly to mostly sunny.

Monday (High 87, Low 65): Partly cloudy with a 20% chance of showers/thunderstorms.

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

(Tea Leaves Territory)

Wednesday (High 89, Low 65): Partly to mostly sunny.

Thursday (High 87, Low 67): Partly cloudy with a 30% chance of showers/thunderstorms.

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

(Beach Forecast)

Wednesday (High 81, Low 65): Partly to mostly cloudy with widely scattered showers and thunderstorms possible.

Thursday (High 81, Low 66): Mostly cloudy and breezy with numerous showers and thunderstorms possible.

Friday (High 84, Low 66): Partly to mostly sunny and breezy with isolated showers or a thunderstorm still possible. 

(Discussion)

Overall it was a mostly sunny day in Cullman today, with a High of 81 and a Low of 54. We did have a period of haze and light rain this afternoon, which was not really in the forecast. But we're getting into summer. (I don't care what the calendar says about that.) And technically any summer day you can have a stray shower or thunderstorm. There are just some days the chance is too low to mention in a forecast. Today was one of those. Jasper saw a High of 82 and Low of 54. And Haleyville saw a High of 82 and a Low of 53. 

Think I'm going to keep this blog on a smaller scale like that, just the immediate area, for the foreseeable future. When I do it at all. 






Our weather pattern is quiet, dominated by high pressure. The high pressure ridge is moving back up toward the Great Lakes region, and this weak tropical disturbance in the Gulf of Mexico will bring us a little moisture over the next few days. 



The rain chances and temperatures look seasonable. Tomorrow should feature a mix of sun and clouds, about a 20% chance of rain, a High near 83, Low near 62. 



Basically the same thing for Thursday.





And for Friday. I don't see any reason to adjust our rain chances between these days, and any temperature variations should only be by a degree or two, probably fluctuations in night temperatures depending on how much moisture is still around versus radiational cooling overnight.

Well let me amend that statement. Things have been hectic on the home front, to say the least. I got mixed up looking at the different days. What I said is true for tomorrow and for Thursday. But Friday, I need to correct what I said. Between the trough/tropical wave in the Gulf and an expanding high pressure system through the Northern Plains, we should see less moisture on Friday with temperatures beginning to rise. I think a High of 86 or maybe even 87 is a good estimate, Low about 63-64 again. Don't think I'll totally take rain chances out. So maybe let's go with 30% chance for tomorrow and Thursday, then decrease it to 20% for Friday to show the trend but that isolated showers/storms are still possible. 



Then going into the extended period, Saturday that trend continues with the upper-level High expanding to our Northwest and us getting into more of a hot/dry pattern. Think I will take out rain chances beginning Saturday, because the chance looks too low to justify putting it in an official summer forecast. Looks like the High will easily get into the upper 80's and we may even reach the 90 degree mark, especially folks in places like Jasper could get there. Low still in mid-60's.



Then on Sunday I'm not quite ready to bring the rain chances back yet. Of course somebody could get a shower or even a thunderstorm, but the chance is so low, not worth worrying about IMHO. Looks like another day with upper 80's for the High and the Low in lower to mid-60's. And it certainly is not out of the question that we reach 90 degrees either Saturday or Sunday. If we do, it'll probably be Saturday, since by Sunday, the pattern shift that will bring moisture back to us on Monday will already be starting. But I doubt it brings us much, if any, rain on Sunday. Think the rain holds off until Monday.



On Monday our moisture should come from the Northeast, showers and thunderstorms rotating around that upper-level Low over the Mid-Atlantic region. Still looking at mid-to-upper-80's for the High, Low in lower-to-mid-60's. Rain chance should only come back up to about 20%. Typical this time of year.


For Tuesday I want to show first that we do have a cold front across the Ohio Valley. Then we'll look at the GFS projection.




For right now, the progress of this front is too questionable to do more than raise the rain chance to 30%. Peeked at the ECMWF and it showed us even drier than the GFS here. Temperatures might come more toward mid-80's and mid-60's here assuming we do get some extra moisture from the front. Close call, and sometimes this time of year I think we're overthinking all the details. When climatology and our past experience of it may give us better data to go on than the models. 



Speaking of overthinking things, I'll have some fun tonight and again lampoon the idea of 10-day forecasts by trying them myself. This look from the GFS next Wednesday supports that idea of a weak frontal passage Tuesday or Tuesday night. So I'll stick with the forecast I discussed above for Tuesday. Looks like we'll dry out again Wednesday, if this guidance is right. But again, anything beyond a week in advance, even in summer, I take with a good pinch of salt. Going to estimate a High in upper 80's again for Wednesday of next week and another drying trend, and if I was taking this model at face value, I'd take rain chances out. But since this is ridiculously far in the future, and I know how our climate usually is here, think I'll keep a 20% chance of rain in there. 



May get a little more moisture on Thursday, so maybe a 30% chance of rain is justified, and a High still in upper 80's, Low in mid-to-upper-60's considering that this slight spike in moisture may actually happen. 



Then on Friday of next week, looking at the general trend, will bring rain chance down to 20% again, feel like we could approach 90 degrees here, but probably not going to put 90 on the official forecast just because it's too far out to make such a drastic estimate. And I really think that once you get beyond seven days, it's about like reading tea leaves or the Farmer's Almanac. I don't figure it can hurt to try it in the summer, with a sense of humor, explaining what I'm doing. And curious to see if I can develop any skill at forecasts at this range. I kind of doubt anyone can. But I've been surprised before. And since I'm not asking you to take it seriously, for any kind of a high-impact forecast, I feel all right about it ethically. I'm hoping some scientific nerd gets a kick out of seeing someone put this much effort into trying a forecast that probably is not any better than the Farmer's Almanac, at days 8-10. Sort of like I'll watch certain political or religious debates just to see if there is a method to some people's madness. Or see just how terrible some professional psychics are at cold reading. There we are back to tea leaves. Maybe I'll try drinking tea this summer. See if I've acquired a taste for it over the years. 

All right, to get serious again, though this forecast doesn't require much of it, compared to the kind of Spring we had . . .



We do have a weak tropical wave in the Gulf of Mexico, which has a lovely presentation on satellite imagery. 


It is a trough of low pressure down there, and the showers and storms associated with it are disorganized. You might notice most of the lightning strikes are inland, it's mainly just rain over the water there. The rest of this week, it should move slowly across the Gulf and is probably not going to intensify enough to be classified as any sort of tropical cyclone. It should move across the Florida Peninsula this weekend. And then as we get into next week, it's expected to be into the Southwestern Atlantic Ocean. So we're really not even likely to see a tropical depression out of this, but as with any tropical low, it has the potential to produce some heavy rains and gusty winds as it moves across the Peninsula of Florida this weekend. 


Around here, rain should be spotty, most of us only seeing a tenth of an inch over a seven-day period, or less than that. But rainfall amounts could be somewhat significant for people in the path of this tropical wave, regardless of whether it tries to develop into a depression (not looking likely at the moment, but you have to keep an eye on all of them this time of year), with South Florida getting up to 3-4 inches of total rainfall. 


Last minute decision when writing forecast, I bought into the idea of a frontal passage a little more for next Tuesday and bumped rain chance to 40%. And adjusting forecast for Wednesday a little according to that. With the understanding that beyond seven days, you can't bank on it anyway. So might as well have fun and see what happens. 

When the forecast is low-impact like this, experimenting with what I really think it's going to do versus stacking the odds in my favor according to the models and the local climate. 

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