Thursday, November 16, 2023

A Couple of Cold Fronts in the Cards

(Forecast)

Friday (High 67, Low 53): Mostly cloudy and cool. Periods of scattered light rain are possible. 

Saturday (High 64, Low 50): Mostly sunny. Cool and breezy.

Sunday (High 66, Low 35): Sunny. Cool - cold in the morning. 

(Extended Outlook)

Monday (High 69, Low 46): Increasing clouds with a 40% chance of showers/thunderstorms.

Tuesday (High 67, Low 55): Rain likely - isolated thunderstorms possible. 

Wednesday (High 53, Low 38): Mostly sunny.

Thanksgiving (High 50, Low 30): Sunny.

(Pronóstico)

Viernes (Máxima 67, Mínima 53): Mayormente nublado y fresco. Es posible que se produzcan períodos de lluvias ligeras dispersas.

Sábado (Máxima 64, Mínima 50): Mayormente soleado. Fresco y ventoso.

Domingo (Máxima 66, Mínima 35): Soleado. Fresco - frío por la mañana.

(Perspectiva Extendida)

Lunes (Máxima 69, Mínima 46): Nubes en aumento con un 40% de probabilidad de lluvias/tormentas eléctricas.

Martes (Máxima 67, Mínima 55): Probabilidad de lluvia; es posible que se produzcan tormentas eléctricas aisladas.

Miércoles (Máxima 53, Mínima 38): Mayormente soleado.

Acción de Gracias (Máxima, Mínima 30): Soleado.

(Notes)

Yesterday was the anniversary of the 1989 Huntsville Tornado. According to a talk I heard from Bob Baron one time, the tornado touched down during a Severe Thunderstorm Warning, which of course was quickly upgraded to a Tornado Warning. That's why I encourage people to pay attention to severe thunderstorm warnings, especially in a threatening atmosphere like had set up on that day. 

This week has been Winter Weather Awareness Week. Which can be good to review even though our winters here are usually mild compared to many other parts of the country. 

Governor Ivey has issued a no-burn order for the state of Alabama because of our drought conditions. 

And James Spann is recuperating after a medical issue that was fortunately easy and quick to fix. Certainly wishing him well and to get as much rest as he needs. On his latest Weatherbrains podcast, the crew interviewed Ashley Gann who used to be the chief meteorologist at CBS-42 I believe. And is doing other things now. 

Almost forgot this, but it is a good time of year to review severe weather safety and make sure that your weather radio has fresh-enough batteries in it for backup. This system on Monday and Tuesday may just bring us some rain without much of a severe weather threat, but it can be a close call this time of year, and it's always good to be prepared. 

And if anybody finds a mistake or can suggest an improvement in my attempts to do the bilingual forecasting, feel free to write me a note or leave a comment. 

(Discussion)



It was a mostly sunny day in the Tennessee Valley with South winds gusting up to about 20 miles per hour at times. The High in Cullman was 75, and the Low was 54. In Jasper the High was 77 with a Low of 52. Haleyville saw a High of 74 and a Low of 55. 

Up in Fort Payne, they had a High of 74 and Low of 53. Gadsden had a High of 76 and Low of 54. Decatur saw a High of 76 and Low of 53. Huntsville had a High of 77 and Low of 56, a few more clouds there through the day than a lot of these other sites. 

Elsewhere around the region, Birmingham also had a good bit of cloud cover today, High of 76 and Low of 57 there. Atlanta also had a lot of clouds today, High of 70, Low of 55. The cities seem to have gotten more clouds today, Nashville had a High of 76 and Low of 54. Memphis had a High of 70 and Low of 54. Back on the Alabama side, Tuscaloosa saw a High of 78 and Low of 58. And our neighbors over in Tupelo, Mississippi, saw a High of 76 and a morning Low of 55. 

And we have a shortwave trough approaching the region at the upper levels of the atmosphere, shown here at 500 millibars/about 18,000 feet, and a cold front down at the surface, which is currently moving through the upper Midwest region. 



Tomorrow that front should bring us some light rain. 


You can see it better on the WPC map than on the raw model data. The day tomorrow should be mostly cloudy and sort of cool, High near 67, Low near 53. Chance of rain about 40%, so at any time of day, showers should be scattered across the map. And most of these should be light showers. This is not a really strong front that's going to bring a good soaking to most places, but every little bit helps with this drought going on. 




Behind the front on Saturday, high pressure moves in from the Mid-South, and we get wind flow from the Northwest in the upper levels. And we will cool off a little bit, starting the day about 50 degrees when the air is still humid, and then warming to about 64 or maybe 65 under mostly sunny skies in the afternoon as the drier air filters in. 



Saturday night is when the real cold snap arrives, and we'll find ourselves down in the mid-30's again by Sunday morning. Then during the day Sunday, plenty of sunshine, warming to about 65 or 66 for the High. And high pressure will be over the region. 



But this is a dynamic time of year for weather, and we have another cold front knocking on our door by Monday. Checked the ECMWF and it is basically on board with this, slightly slower timing but same day at least. Probably going to go ahead and put rain chances back into the likely range here. Expecting a High in the upper 60's and Low in the mid-40's. So that's borderline for if we see any storms usually. Will check the forecast instability levels below the main forecast discussion, just to double-check this time of year, since November can be stormy sometimes. 



Again, this does look like good agreement between the American and European global models, though I'm only showing the GFS here, the American one. This looks like a fairly strong cold front, and Tuesday will feature likely rain chances for sure. Again it's dicey whether we'll be unstable enough to get thunderstorms, much less any that become severe. But November tends to be a secondary severe weather season for North Alabama up into Tennessee, so we do have to keep an eye on these things just to play it safe. For now expecting a High in mid-to-upper-60's and a Low in lower-to-mid-50's. 



Then on Wednesday, skies quickly become mostly sunny behind that front. And it is a strong cold front that will knock the overnight temperature back down in the upper 30's and then we only warm to the 50's during the day. Don't think we'll make it to mid-50's, probably just lower 50's despite plenty of sunshine. 



Then the high pressure really settles in for next Thursday, which of course is Thanksgiving. We'll see a High near 50, Low near 30, sunny skies. 

And I started to speculate on Black Friday and the weekend beyond, but in a dynamic time of year like this, I'm less a fan of 10-Day-Outlooks. Even in boring weather patterns, I call days 8-10 reading tea leaves. Main thing to know about that weekend is that you need to be careful driving, watch the other people especially, whether you're driving to a ball game, a concert, or just to go shopping. And frankly, sometimes I've started to wonder if the greater danger shopping isn't once you get indoors. People go absolutely nuts sometimes, running each other over trying to get this or that toy or video game system or other gadget. Meanwhile more sensible animals, such as my cat, Salem, prefer to hibernate at times, and swat around random objects at others, maybe go enjoy the sunlight at times. Seriously, the weather looks great going into the holiday, but please be on the lookout for shoppers or drivers whose behavior might remind you of a crazed cat that's been fed six or eight cans of Red Bull and then given some sardines and a ball of yarn. 


In the tropics, we do still have some activity even though the season is just about over with. That area of low pressure near the Northwestern Bahamas is not expected to do anything besides continue to produce heavy rains and gusty winds. It is actually along that front stalled out down there in the Gulf of Mexico.

The other system has already been named Tropical Depression 22. Even though it hasn't developed into that yet. 



And there is good reason for getting ahead of this thing, the National Hurricane Center calling it a potential tropical cyclone for now. It is expected to become a tropical storm tomorrow. 

It has been a broad area of low pressure over the Western Caribbean over the past few days. An Air Force Reserve Hurricane Hunter has helped confirm what was seen on satellite imagery, that there is a closed but broad circulation that has developed. There is not yet a well-defined center. But there are some major rain bands spreading far North of the broad circulation toward the Greater Antilles. 

Without a well-defined center, the movement is somewhat in question, but with a trough over Florida, the most likely direction is toward the Northeast. There is a lot of dry air and southerly wind shear that will probably keep this thing below hurricane strength. Plus it is broad and lacks a well-defined center. 

Places like Jamaica, Southeast Cuba, Haiti, the Southeast Bahamas, and the Turks and Caicos Islands may experience tropical storm conditions tomorrow and Saturday. And those places have been put under a Tropical Storm Watch. 

And through Monday morning, places like Panama, Costa Rica, Jamaica, Southeast Cuba, and Hispaniola are likely to have heavy rainfall that could lead to flash flooding and even mudslides. You have to remember they have a lot more mountains in some of these places, and that can be an issue even with a tropical storm, doesn't take a hurricane. 



By Monday evening, the GFS is now showing some decent combination of instability and wind shear out to our West in more of the Mid-South region. So like I said above, we will have to watch Monday into Tuesday for a potential for some thunderstorms, keeping in mind that November can bring severe weather to our region. Taking a forecast sounding from Southern Arkansas, it looks like a fairly typical low instability/high shear setup. And even having said that, sometimes you see a lot more shear than this in the cool season. So right now, around here, all I'd advise people to do is keep an eye on it, see how things trend over the weekend. And if you've got relatives coming over early next week because of the holiday, might go over your severe weather safety plan with them. Hopefully you don't need to use it, but if they are not from Alabama, they might not know that we have severe weather sometimes at this time of the year. I wouldn't get overly concerned about this as of right now. Usually with a setup like this, instability will end up being limited. But in case we get more of a warm sector that includes North Alabama, I do advise people to sort of keep an eye on it. 


Our rainfall totals over the next seven days will probably be between about an inch and a half-inch. And with the front Monday and Tuesday, we could see some locally heavier showers or storms in some places. We definitely need the rain, and if we were to see any stronger storms, the silver lining to that would be that it could help us out a lot more with the drought than a routine rain event. 

P.S. Adding this at 10:07 PM because I saw something while randomly scrolling that I forgot to check when writing up the forecast discussion.



The Storm Prediction Center has already outlooked a basic 15% risk for severe thunderstorms for some areas in the Plains on Sunday and parts of the Southeast on Monday. For now they are thinking it will stay in Southern Alabama and Mississippi, some potential also back into Louisiana. It's like any such threat around here any year, this time of year, you have to watch the trends and see how far North the unstable air gets. Sometimes we don't even get enough for thunderstorms in North Alabama or into Tennessee, much less anything severe. So it is worth keeping an eye on, but for now, looks like the main risk will be more toward South Alabama. 

No comments:

Post a Comment

Hot Summer Pattern, Keeping an Eye on Tropics

FORECAST: Friday (High 93, Low 67): Sunny. Hot and humid.  Saturday (High 95, Low 69): Sunny. Hot and humid.  Sunday (High 96, Low 71): Most...