Friday, February 24, 2023

More Rain Tomorrow, Break in the Action Sunday

Saturday (High 62, Low 51): Mostly cloudy. Periods of scattered showers are possible. 

Sunday (High 71, Low 53): Partly cloudy. Clouds increasing in the evening, becoming breezy.

Monday (High 73, Low 60): Windy and rainy. Isolated thunderstorms are possible and may produce strong, potentially damaging winds - that risk is mainly in far Northeast Alabama up into Tennessee.

Tuesday (High 70, Low 49): Sunny.

Wednesday (High 74, Low 52): Partly to mostly cloudy. 

Thursday (High 72, Low 59): Thunderstorms likely. 

Friday (High 67, Low 53): Showers likely - thunderstorms possible. 

This has been Severe Weather Awareness Week for Tennessee. And tomorrow will feature an all-day Severe Weather Awareness Day on a college campus in Nashville - follow link for more details on that. 

Also a salute to Elizabeth Leitman, who recently became the first female forecaster to issue a severe thunderstorm watch at the Storm Prediction Center. She was recently on the Weatherbrains podcast

All right, so as we approach 5 PM, it is still a little drizzly and overcast in Cullman. But the visibility is perfect at ten miles. Winds are calm. It is 50 degrees, with same dewpoint, making the humidity 100%. Barometric pressure is 30.35 inches and steady. Overall we have had an overcast day with periods of rain, and a pretty good breeze much of the day, usually from the North or Northeast. And I really made a mistake with this forecast yesterday, undercutting the model guidance for how much lingering moisture we would have. I had taken a couple days off posting any updates and really did not believe what the latest model guidance was showing versus what I remembered of the pattern before. The models definitely got it right this time. The temperatures were going backwards today. Our High was 68 back at midnight, and then our Low may not get much (or any) below our 2 PM temperature of 48. It is overcast and 54 degrees in Jasper, North winds at 3 mph. Light rain and 49 in Haleyville. 

That front is down around Mobile, but we still have plenty of moisture up this way. Further North, parts of Illinois and Missouri have a wintry mix, while the organized snow is still up around the Great Lakes region. Also got some snow and ice out in Nevada and much of California associated with a different cold front. Pacific Northwest has high pressure dominating their weather now for a change. And that ridge of high pressure continues to hold strong over Florida. 

Then tomorrow, that front will continue to move very slowly, more-or-less stalled out around Montgomery. Which will keep rain chances in our forecast. It really looks like a repeat of today as far as overcast and periods of rain, can trim rain chance to 40%. Should have gone with 50% for today's forecast, but like I said, I took the wrong approach yesterday. High should not get much above 60 tomorrow, Low should be near 50. 

Then on Sunday, major snows again West of the Rocky Mountains, behind a front that will bring an organized severe weather potential to the Great Plains. Still some icing going up around the Great Lakes. Think most the Midwest will be in the thunderstorm sector for this. And even though the maps here are showing rain and thunderstorm chances hanging around for us, I am leaning away from that. I think the high pressure centered over Florida and the Carolinas will have more an influence on our weather for Sunday. Should see a High of 70 or so, Low in the lower 50's. We may see more clouds than sun overall, but if we see a shower anywhere, I think that'll be isolated. I think we do get a break from the rain for one day anyway. 

The Storm Prediction Center is taking the threat for severe weather out in the Plains seriously, issuing 15-30% chances for organized severe storms over much of North Texas, Oklahoma, and Southern Kansas a couple days in advance. Marginal chances for severe thunderstorms stretch all the way up to Kansas City and into Central Texas, clipping Northwest Arkansas as well. 

As of right now, it is looking unlikely that this threat will extend into our region as a whole on Monday. But there is a basic 15% severe weather outlook for East Tennessee and Kentucky, so places like Chattanooga and the Smoky Mountains, definitely a chance for at least some thunderstorms capable of some damaging winds on Monday. 

The NAM is showing enough instability and wind shear to notice in the afternoon hours on Monday. The greater focus for it is up where the severe weather outlook area is, up in the mountains of East Tennessee and Kentucky. 

Looking at forecast soundings for Cullman and Huntsville, this is a marginal severe weather setup at most. Looks like a deal where isolated damaging winds might be possible, but really, probably more just rain and wind where thunderstorms have a hard time sustaining or even getting going, not a lot of unstable air to even work with.

The Low associated with this system looks like it is heading well up into the Midwest anyway. And the ingredients are just not coming together well in our region for any organized severe weather. It is kind of dicey how many thunderstorms we even see. Definitely will be dealing with some gusty winds though even outside of thunderstorms. Some of that breeziness may even start Sunday night. Looks like a High in the lower-to-mid-70's, Low of about 60 or so. 

Then we catch another break on Tuesday, with high pressure moving in from the Midwest. Should be a sunny day with a High near 70, Low near 50. The Low may even dip into the upper 40's, because it looks like that front is going to clear the area pretty quickly overnight. 

Then on Wednesday it lifts back northward as a warm front. This is definitely an active pattern like you'd expect going into the month of March. It seems like the active pattern got going a little ahead of schedule this year. Looks like a mix of sun and clouds, clouds on the increase toward the evening and night hours, probably not going to see any rain Wednesday, if so very isolated. High in the lower 70's, the Low about 50 or so. 

Then rain and thunderstorms are back in the cards for Thursday. Cold front coming back through the region. Low rebounding to upper 50's, High only about 70 or so.

On Friday the forecast gets messy with some differences between the GFS and ECMWF models that I'm not showing here. I think the ECMWF is in too big a hurry with this system, and will keep likely rain chances in the forecast for Friday, High back down into 60's, Low in the lower 50's. 

Strangely the second of the two days, Friday, is when the GFS is showing some concerning parameters for any organized severe weather. But even if this verifies, looking at a forecast sounding up around Ardmore, it looks like a setup with very low instability but enough wind shear to overcome it for a damaging wind threat and maybe an isolated tornado threat. And it is mostly showing up for our Eastern counties. 

Honestly the extended for Thursday/Friday looks too messy to speculate on for right now. Looks like another rainy/windy setup with more potential for thunderstorms. And you do have to watch this time of year for any trends toward stronger storms. 

Looking at the analog guidance, I wouldn't totally dismiss the chance of a few storms becoming severe on Monday, but the risk looks on the low side for Alabama. Places like Sewanee and Jasper, Tennessee would have a better chance, and places like Chattanooga, stretching on up into Kentucky. The SPC guidance looks on track, but I would not be totally surprised if we had an isolated strong storm or two on the Alabama side with some high wind gusts anyway. And then looking at analogs was no help at all for Thursday/Friday. Will just have to keep an eye on that in case there is severe weather potential. It does look like a good soaker and probably a lot of wind energy regardless of whether we see much in the way of storms. 

It is now looking like over the next seven days, we'll see up to about 2-3 inches of rainfall on average. The higher amounts will probably be in Tennessee, especially Eastern Tennessee. 

And here almost as a footnote, I'll put a link to my version of severe weather precautions that I wrote up last night. It needs editing and rearranging, but I'll get to that later. Just in case someone stumbles on this blog post who is new to the area and doesn't know much about how things work this time of the year. They might get something out of it. 

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