Saturday, November 23, 2024

Dynamic Weather Pattern This Coming Week, Rainy and Maybe Even Stormy For Thanksgiving

FORECAST:

Sunday (High 63, Low 32): Sunny. Patchy frost possible in the morning. 

Monday (High 70, Low 46): Breezy with increasing clouds during the day. Rain showers are likely at night. 

Tuesday (High 56, Low 44): Mostly sunny. Breezy.

EXTENDED OUTLOOK:

Wednesday (High 61, Low 38): Partly cloudy. 

Thanksgiving (High 66, Low 50): Rain likely - thunderstorms possible, and could be strong. 

Black Friday (High 50, Low 37): Mostly sunny with hazardous shopping conditions. 

Saturday (High 51, Low 29): Sunny. 

PRONÓSTICO:

Domingo (Máxima 63, Mínima 32): Soleado. Posibles heladas dispersas por la mañana.

Lunes (Máxima 70, Mínima 46): Ventoso con aumento de nubosidad durante el día. Es probable que haya lluvias por la noche.

Martes (Máxima 56, Mínima 44): Mayormente soleado. Ventoso.

PERSPECTIVA EXTENDIDA:

Miércoles (Máxima 61, Mínima 38): Parcialmente nublado.

Día de Acción de Gracias (Máxima 66, Mínima 50): Probable lluvia; posibles tormentas eléctricas, que podrían ser fuertes.

Viernes Negro (Máxima 50, Mínima 37): Mayormente soleado con condiciones peligrosas para las compras.

Sábado (Máxima 51, Mínima de 29): Soleado.

DISCUSSION:





As we get close to 2 PM, latest observations show sunny skies in Cullman, and so does looking outside. That report of sunny skies has been verified by a reliable spotter. The temperature is 55 degrees. The dewpoint is 41 degrees, making the relative humidity 59%. Winds are variable at 5 miles per hour. The pressure is 30.12 inches and steady. The Low this morning was 30 degrees. 

It is sunny and 59 degrees in Jasper. The dewpoint is 41, making the relative humidity 51%. Winds are out of the West at 7 mph. The pressure is 30.13 inches and falling slowly. The Low this morning was 28 degrees. Been a while since we've been this cold, a foretaste of the winter season, which is not far off. 

It is 56 degrees under sunny skies in Haleyville, with a dewpoint of 38, making the relative humidity 51%. Winds are West at 7 mph. Pressure is 30.14 inches/996.9 millibars (kudos to them as usual for giving observations in millibars) and falling slowly. The Low this morning was 29. 

Elsewhere around the region, Fort Payne is sunny and 57 degrees. Decatur is sunny and 54. Huntsville is partly cloudy and 55. Muscle Shoals is sunny and 57. Tupelo is sunny and 59. Memphis is partly cloudy and 56 degrees. And Nashville is drunk and musical . . . but also partly cloudy and 52 degrees. Their Low was only 37 up there this morning I see, thanks to some cloud cover preventing as much radiational cooling overnight. 

North Central Alabama has several counties under a Frost Advisory or Freeze Warning again tonight. 

We have high pressure in place, but our upper-air pattern is opposite of what it was before, with a strong trough in place over our part of the country, strong Northwest wind flow at 500 millibars/about 18,000 feet. And there's a pretty good upper-level Low up there just off the coast of New England. 


Meanwhile we've got a front and more low pressure moving through the Pacific Northwest and affecting everywhere from North Dakota to Wyoming to Nevada with mixed wintry precipitation today. Which is a lot of what they're having up in New England too. 

A lot of us are already at or near our High temperature for today, it gets dark so early this time of year, mid-to-upper-50's. 


That front will make some progress tomorrow and bring some snow to Wyoming and Montana, some in North Dakota up northward across the Canadian border, also some rain to parts of the Midwest and Ohio River Valley on the warm side of the system. 

Around here we'll have sunny skies again, a High near 63 and a morning Low near freezing, about 32 degrees, so will have to watch for patchy frost tomorrow morning. 


Then on Monday that front will bring rain to a large chunk of the Eastern U.S., and that includes us. Although it looks like we'll just see an increase in clouds during the day, with the rain holding off until the dark hours around here. High should get to about 70 degrees, and the morning Low will rebound well into the 40's, upper 40's, about 45-48 range. 

And the winds will get breezy, gusty on Monday/Monday night. Should be from South/Southwest.


High pressure behind that will bring us mostly sunny skies again on Tuesday and temperatures feeling like winter time again. Looking at a High in the mid-50's and Low in the mid-40's. And it should still be breezy at times, at least in the morning, winds shifting back to the North. 


Then Wednesday looks like a mix of sun and clouds as we are between systems. High of about 60 or so, morning Low in the upper 30's. We may see some rain move in during the dark hours, but the timing looks like it would make it in the wee hours of Thursday morning. 



Thanksgiving Day continues to look interesting. I haven't been posting about it, but I've kept up casually with trends. The models keep flip-flopping on the details. But this is worth watching. November often brings us chances for severe weather. And on this latest run, it is the GFS that is showing a more favorable track of the surface Low pressure system to support something like that, at least a low-end threat for stronger storms. In some previous runs, the European model was the one showing more of that potential, while the GFS just had us rainy. But let's look at what the models are spitting out right now and give it some thought. 




Between Midnight and Daybreak, the GFS shows a marginal combination of unstable air and wind shear that, taken together with this cold front moving in, could produce a few severe thunderstorms in the region. Let's take a look at what the specific parameters are locally, forecast to be locally, at Daybreak, 6 AM on Thursday. 


And at the junction of Cullman, Winston, and Walker Counties, the GFS is showing only marginal instability, about 500 j/kg of CAPE, which is enough to work with this time of year, but on the low end any time of year. And the wind shear is also enough to work with, but the directional shear doesn't look impressive, the storm relative helicity values staying under 200 m^2/s^2. Which means if this verifies, this would be a lot more of a chance for damaging straight-line winds in any thunderstorms that become severe, than a tornado threat. And you could see some hail with this setup, but a lot of it would probably stay below severe criteria, which is the size of a quarter - inch in diameter. 


The ECMWF is now showing such a northward track of the Low that I wouldn't even worry about severe weather at all with this look. But remember, a few days ago, it was this European model that first got everyone's attention, by showing what the American model wasn't, which was a track of the surface Low that would be classic for a severe weather outbreak in our region. So we have to remember that and acknowledge that the models have been very inconsistent in what they are forecasting for Thursday, as far as the positioning of everything. This still bears careful watching, considering it is a holiday and that the rain/storms will start in the pre-dawn hours for a lot of people. 

And the SREF guidance doesn't go out to Thursday yet. 


The European model is also showing in the early morning Thursday, dewpoints getting up into the 60's in Central and North Alabama. That lines up with what the GFS was showing via CAPE values of about 500 joules. 

This is a marginal situation that bears careful monitoring over the next couple days and then of course up until the event, if there is anything more than a rain event. We could see some severe thunderstorms. It does not take much instability to fuel them this time of year, and the models have been all over the place with the placement of the Low pressure center, which will make a lot of difference as to where the best wind shear is, as well as the unstable air. Some of the scenarios over the past few days have shown us with plenty of unstable air and ample wind shear, even to a support a tornado threat. So for now the threat is looking lower, and like we'd have more of a straight-line wind threat, if we do get anything. That's how it looks right now. 

But you have to second-guess the models sometimes. And they have not been consistent with this. The best thing to do is to be near a place you could take reasonably good shelter on Thursday if severe weather were to threaten. That means a small room (or hallway) without windows down on the ground floor of a sturdy house, not a mobile home. If you've got a place like that to go if you need it, then you should be fine, even if the day does turn ugly for some people. 


Rain is likely on Thursday, and we'll start the day around 50 degrees. The current model guidance is showing a High near 60, but I'm thinking mid-to-upper-60's is more realistic with this setup. If it ends up being cooler like the current model trends, then few if any of us are going to see any severe thunderstorms. That would just be a cool rain, especially if a lot of places are not making out of the 50's. 



We should see rapid clearing on Friday with skies becoming mostly sunny again, High struggling to get up to 50, morning Low in the upper 30's. 

And then Saturday, sunny skies, High near 50, Low down near 30 again, perhaps even dipping into the upper 20's. 

So we are mostly staying cold for this forecast, just mainly have to watch Thanksgiving Day in case it gets stormy. And of course it's a drag for it to be rainy anyway when so many people are travelling. At least on Black Friday, as usual it looks like the hazards will be indoors, like just try not to get run over by the nearest maniac trying to rush to get the fanciest toy off the shelves before you do. 

Hey, on that note though, the better side of Christmas coming up next month, a friend of mine took his kids out to the Christmas parade in Cullman last night, and his twin girls actually got interviewed by ABC-33/40, who were broadcasting from the event. Sounds like people were together in a good spirit. I'm not a big fan of Christmas because of a lot of bad memories with my family associated with that holiday after I got past being a kid, but if I don't shave my beard soon, I'm gonna' start to look like Santa Claus. Ho ho ho . . . 

And it's a happy holiday for a lot of people. I do like some of the movies. Just don't any of you people ask for a BB gun. You'll shoot your eye out. 

Somerset Maugham wrote a great Christmas novel, although literary snobs tend to think it was one of his worst efforts. And nobody reads Dickens anymore because of all the awful movies they made out of it. The Muppets actually made a good one . . . strangely enough.  


We'll see about an inch of rain over the next seven days on average. Some places in Northeast Alabama and into Middle Tennessee may see closer to two inches. 


I'm mostly trying to let this site die a natural death, but things like a potentially stormy Thanksgiving still get my attention. So blame it on the weatherman . . . oh wait, that's me . . . ah well . . . I would say blame it on Mexico, like the old George Strait song, but that's way too fashionable these days . . . blame it on my doofy cat who failed to use the litter box several times lately and bounced around and broke two coffee mugs in the space of two or three days. And knocked my weather radio around. Let's blame this blog's continued existence on a psycho cat making its owner weary but with a restless mind. 

I still don't know if the Spanish is all that accurate, but I don't think anybody reads it anyway. 

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