Saturday, May 4, 2024

Unsettled, Warm Pattern with Low Rain Chances Until Late in the Week

FORECAST:

Sunday (High 85, Low 60): Mostly sunny with an isolated shower or thunderstorm possible during the day. Rain is likely at night. 

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

Tuesday (High 85, Low 64): Mostly sunny. An isolated shower or thunderstorm is possible. 

EXTENDED OUTLOOK:

Wednesday (High 86, Low 65): Mostly sunny with a 20% chance of a shower or thunderstorm. 

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

Friday (High 80, Low 66): Partly to mostly cloudy with a 50% chance of showers/thunderstorms.

Saturday (High 76, Low 55): Mostly sunny. 

PRONÓSTICO:

Cinco de Mayo (Máxima 85, Mínima 60): Mayormente soleado con posible lluvia o tormenta aislada durante el día. Es probable que llueva por la noche.

Lunes (Máxima 83, Mínima 62): Parcialmente nublado. Aún son posibles lluvias y tormentas muy dispersas.

Martes (Máxima 85, Mínima 64): Mayormente soleado. Es posible que se produzcan lluvias o tormentas aisladas.

PERSPECTIVA EXTENDIDA:

Miércoles (Máxima 86, Mínima 65): Mayormente soleado con un 20 % de probabilidad de lluvia o tormenta eléctrica.

Jueves (Máxima 84, Mínima 68): Mayormente nublado con un 50 % de probabilidad de tormentas eléctricas.

Viernes (Máxima 80, Mínima 66): Parcialmente a mayormente nublado con un 50% de probabilidad de lluvias/tormentas eléctricas.

Sábado (Máxima 76, Mínima 55): Mayormente soleado.

DISCUSSION:





At 7 AM skies are partly cloudy in Cullman. The temperature is 66 degrees. The dewpoint is also 66 degrees, making the relative humidity 100%. Winds are from the South at 3 miles per hour. Barometric pressure is 30.05 inches and steady. They still haven't upgraded to millibars for most of the local observations, but now the pages I find easier to use have upgraded to giving exact temperatures. Like technically the temperature and dewpoint are 66.2. But I round it to the nearest whole number. It's just easier for people to understand. 

It is partly cloudy in Jasper, and they've had quite a bit of fog this morning. 


In fact, they are included in a Dense Fog Advisory through 9 AM. So are Winston, Marion, Lamar, and Fayette Counties back into Mississippi and also as far East as Hardin County, Tennessee. 

Jasper is also 66 degrees and 100% relative humidity. (Dewpoint and temperature are the same.) Winds are calm. The pressure is 30.04 inches and rising. Visibility is back up to 8 miles now, but when the fog was heavy even one hour ago, it was down to way less than a mile. 

I see that the latest observation we have for Haleyville is from 6 AM, but I guess I'll go ahead and give it. Foggy and 64 degrees, 100% relative humidity, visibility down to a quarter of a mile. Pressure 30.05 inches/1015.9 millibars and rising. Winds out of the Southwest at 3 mph. 

Fort Payne has light rain and fog, 65 degrees, visibility restricted to 4 miles. Gadsden also has light rain and fog, temperature of 66, visiblity 6 miles. Decatur is mostly cloudy and 67, visibility 8 miles. 

And by the time I've gotten to Huntsville, it is a little after 8 AM. I didn't really start collecting observations at 7 AM, closer to 7:45 or so. It was just that the latest observations for the sites were from 7:00 or around that time. So now we move into the 8 AM hour. 

Huntsville is partly cloudy and 70 degrees, a perfect 10 miles of visibility. Muscle Shoals is overcast and 69. Tupelo is also mostly cloudy and 69. Memphis has fog and mist, 68 degrees, visibility down to 3 miles there. And Nashville is mostly cloudy and 68, perfect 10 miles of visibility there. Except for those with a hangover, who might still find their visibility restricted in ways that have nothing to do with the weather. Something tells me this might be more common along Broadway or wherever the nearest Waffle House is to those bars.


The last of some overnight showers are clearing out of Northeast Alabama at this time. So people in Georgia up through the Smoky Mountains get to enjoy more of the rain. We do also have isolated showers across Middle Tennessee, about as spaced out as you'd see on a summer day. 

The major weather action has stayed to our North and West for a while now, a lot like you'd see in summer. So before we get into the local forecast, might take a look at out West. 




And the first three days of this month have been busy out there. Some of these tornadoes in Texas have produced some crazy radar signatures too. There was one near Hollister, Oklahoma recently that looked like it had an "eye", sort of like a hurricane. It is really too much to keep up with and report on this blog. This is mainly focused on our local weather. But it sure has been strange out there lately, and continues to be active. Here is a link to a pretty good story about some of the unusual tornado phenomena lately, including one that was anticyclonic. It was spinning backwards, clockwise instead of the usual counterclockwise motion you'd see in the Northern Hemisphere. 

Those folks just have not been able to catch a break lately though, just one severe weather event after another. 



They actually have a risk today, mainly over Texas, especially the Central and Western parts of the state, but also stretching well up into the Midwest, chance of some isolated severe thunderstorms. Things in Texas could get fairly organized again. The tornado threat is substantial, especially in that Enhanced Level 3/5 Risk area. 


Tomorrow maybe the country catches a breather, as the most anyone has is that lowest Marginal Level 1/5 Risk category for severe thunderstorms. That just means something isolated could develop, but the chance is really low. That marginal risk area does include much of Mississippi tomorrow though. Back in the old days, this low of a risk wouldn't even be drawn on the maps. Those areas would just have a note "SEE TEXT" written over them. I think they introduced the Marginal Risk in about 2014 or so. There used to only be three risk levels: 1. Slight 2. Moderate and 3. High. Now we have 1. Marginal 2. Slight 3. Enhanced 4. Moderate and 5. High. So the outlooks are more detailed for forecasters to use, but can be trickier to explain to the general public sometimes. 




Monday looks like it could be a real bear for the Plains. Not that they need that again, but hey, we're in sales, not production. That looks like it could be a significant severe weather outbreak for much of Oklahoma, Kansas, even parts of Nebraska and maybe up around places like Kansas City, Missouri. I know you can see a tornado coming for miles in that part of the world, but still, I can't say I envy those people. The storm chasers are having plenty of fun, but for regular people trying to just do their everyday lives, this has been a rough time. 



Tuesday and Wednesday, it looks like the severe weather risk will shift more into the Midwest, Mid-South, and Ohio Valley. On Wednesday the basic 15% (pretty much translates to the standard "slight" risk you see on Days 1-3 outlooks) risk does include roughly the Northwestern half of Tennessee. As of now doesn't quite make it into Northwest Alabama. 

So that's a good cue to get to the point and look at our local weather for the next week. 

Today is going to be a lot like a summer day but with cooler temperatures. Probably see a High of about 80 for Cullman, a few places nearby might see more like 82 or 83. Chance of seeing additional showers and thunderstorms behind the morning round is about 1-in-5. They should stay pretty isolated. 



Then tomorrow the rain chances look pretty limited again, should stay isolated, about a 20% chance of any one spot getting a shower or thunderstorm, so again a lot like a summer day. The High should get to about 85, the Low around 60. 


Now tomorrow night does look like a soaker. 



Basically tomorrow night into Monday a shortwave trough from the Plains will spread some rain this way and produce what amounts to a weak warm front over the Tennessee Valley. 


The NAM is nowhere near as impressed with our rain chances during the day Monday as the GFS is. 

I think it's enough to increase the rain chance to 30-40%, probably going to trend toward being conservative in this unsettled pattern, not overdo the rain chances when the pattern is summerlike. But will review day by day before making a final decision. Have to look at each day individually and then decide how the overall pattern looks. Most of this week will be a summerlike pattern, but then toward the end of the week, looks like we may see a frontal passage. So things will change after that. 

Anyway looks like a High of 80 or so again on Monday, Low in the lower 60's. 



The latest run of the GFS dries us out on Tuesday. 


The ECMWF keeps isolated rain in the forecast, and that is probably closer to the truth. I'm thinking of this pattern a lot like if it was already summertime. You can't rely on the models all that much, as much as you have to look at what the overall pattern usually produces around here. 

So rain chance of 20% seems reasonable here, probably looking at a High in the lower 80's, Low in the lower 60's. 



Wednesday also looks mostly dry, but again, since we're staying in a summerlike pattern, have to consider isolated showers and thunderstorms being possible. And for some of these days, there are rabbit holes we could go down with some model guidance suggesting mesoscale convective systems from out West. But those are hard to predict even in summer. And that model guidance does not strike me as clear enough in this setup to really go into detail about. We always have to watch for MCS in the summer too. And this pattern is summerlike, where we've got a ridge of high pressure close enough to keep us mostly dry, but some rain and thunderstorms can sneak in at times and get past it, some days more than others. So for Tuesday and Wednesday going to keep the rain chance down at 20% but also mention more sun than cloud cover. It really does look like a typical day in summer. For Wednesday we might see a High more toward the mid-80's and Low in mid-60's. 

Much like the rain chances, the temps will be a tough call to review after looking at each day individually. In a sort of blocked-up summer pattern, it's good to look at the overall trend and make the best estimate. Where if the weather is really dynamic with a lot of temperature shifts, strangely that can be less challenging to forecast sometimes. 



If there is a day we need to keep an eye on, as far as more organized thunderstorms or any stronger storms that could get organized, it is Thursday. Global models are in good agreement that the cold front will finally start to move into our region Thursday and Thursday night. And we are still in early May, still in our main severe weather season. Sometimes we even have severe weather in late May around here, but it usually calms down by about middle of this month, and we get into more of the usual summer type weather. 





As of right now, the GFS is showing way more than enough unstable air to support severe thunderstorms on Thursday evening but very weak wind shear. So this could mean a threat for large hail and some damaging thunderstorm winds. And it's just something to keep an eye on. The SPC has not introduced a severe weather risk for our region on Thursday because it's really too soon to call. The model guidance should make it clearer where (and if) to draw a risk over the next two or three days. 

Will put the rain chance at 50% Thursday. Rain will be likely Thursday night, but I think 50% is enough to cover the daylight hours. High should be in lower 80's, Low actually in the upper 60's as the air is a lot more moist. It doesn't look like a big severe thunderstorm potential, but considering the time of year, and that we'll have warm air in place ahead of a cold front finally passing through the region, always have to keep an eye on how things trend. Could at least see an isolated storm or two that try to get out of hand. 



The GFS shows a pretty swift frontal passage on Friday. 


The European solution is more gradual. 

Nothing surprising, especially at this time range. 

Will keep rain chance at 50% and forecast a High near 80 or maybe upper 70's, Low still in 60's. 



Then as hard as it may be to imagine, next Saturday looks mostly sunny with a High in the mid-70's and a Low back down in the 50's, probably mid-50's. 


And we'll see an average of about two inches of rainfall across the region during the rest of this unsettled period. Most of that will probably come tomorrow night/Monday or on Thursday/Friday. But a lot like in summer, we could get a surprise or two, a heavier shower somewhere on a drier day for most of the region, or some people who pretty much miss the rain when the radar is a lot busier. 

Seeing that Mark Hamill showed up at a White House press conference, and then the Babylon Bee went ahead and lampooned it before I'd even caught the original story, today I'll divide my parting words between the two political parties. 

Star Wars fans: May the Fourth be with you. 

Monty Python fans: Always look on the bright side o' life . . . 

(Independents: I DUNNO! YOU'VE GOT TO WORK IT OUT FOR YA'SELVES!)

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