A dynamic weather system is poised to bring severe weather to Alabama today.
The Storm Prediction Center continues to have the southern two thirds of Alabama in a moderate risk outlook for severe weather today. That moderate risk extends roughly north to Lamar… Fayette… Jefferson… southern St. Clair… southern Calhoun and then to Randolph County. The rest of North Alabama is under a slight risk outlook.
Tornado watches continue for nearly all of Mississippi as well as West Alabama this morning. Severeal severe thunderstorm warnings continue along and ahead of the squall line back in Mississippi.
So, this is a significant severe weather situation. Very strong low pressure is just south of Memphis at 8 a.m. Barometers are reading very low in that area. At Greenville, MS. the adjusted sea level pressure was 29.30 inches. At West Memphis, Arkansas, it was 29.28. This equates to about 991.5 inches, which our friend Kevin Sele noted from a Hot Springs, AR observation earlier. These are readings you would see in a strong tropical storm. Strong winds are blowing at the surface around this low also, averaging some 10-20 mph and gusting to 25 mph or higher at times.
A warm front is moving northward through Alabama this morning, with widespread moderate to heavy rain and some embedded thunderstorms are along and ahead of it. Most of the state east of I-59 is getting that rain. South of the front, dew points are juicy, in the middle and upper 60s back over Mississippi. The dew point at Jackson had reached 67F.
Several things cause us concern with this system. One, the low pressure system is acting like a powerful pump, pulling lots of high dewpoint air northward as I mentioned. That is high octane fuel for storms. Second, with some breaks in the clouds behind the front and initial shortwave, we could see temperatures warm to near 70 today. Partial clearing is evident on the Tuscaloosa Skycam. This will create sufficient instability for a few isolated supercell storms before the main line gets here later. Thirdly, the wind fields are very, very strong with the intense low pressure close by. Shear values are way up the scale, and this can lead to lots of severe weather, including tornadoes, even if the instability is marginal.
We will also deal later with a squall line that is now over western Mississippi, but racing eastward. It will reach West Alabama around 10 a.m., I-65 around noon and into East Alabama during the early afternoon. Wind damage and embedded tornadoes will be the threat with this active line.
Some nice rainfall amounts overnight and this morning. Brian Peters reports 0.95 in Helena to bring his storm total to 1.26. Spann reports 0.83 in Greystone Cove. Radar estimates indicate that places from Coosa County back through Marengo County may have gotten two inches or more.
This will be the kind of day that where you will want to pay attention to the latest weather information. J.B. and I will have frequent updates here on the ABC 3340 Weather Blog.
Far away from our little world…a Tsunami Warning is in effect which includes the Alaska coastal areas from Sand Point, Alaska to Attu, Alaska. A Tsunami Watch is in effect for the Washington, British Columbia and Alaska coastal areas from Cape Flattery, Washington to Sand Point, Alaska. Tsunami warnings are in effect for parts of Japan and Russia. All this because of a major earthquake in the Kuril Islands this morning. The magnitude of the quake was 8.1. By comparison, the quake that caused the December 2004 Indonesian tsunami was a 9.1. So far, the tsunami waves generated have been minor, less than one and one half feet.
