A moist airmass continues across Alabama on this Sunday.
But thick cloud cover has kept temperatures below the convective temperature, or the temperature at which showers and storms form. But highs should top out in the middle to upper 80s this afternoon, allowing showers and storms to eventually form.
That was starting to happen around over southern Tennessee and northwestern Alabama where instabilities are greater due to more sunshine.
These storms will push southeastward into Central Alabama even as other storms form. Not much change is expected tomorrow either as the moist airmass and disturbances remain in place.
Thunderstorms are increasing in coverage and intensity across Alabama in a soupy, unstable summertime airmass.
Storms in the Montgomery area have become severe and there is still a severe thunderstorm warning in effect for part of DeKalb County.
The NWS Birmingham issued a Severe Thunderstorm Warning for Elmore, Macon and Montgomery Counties till 4:30 PM CDT.
Storms are strongest over Northeast, South Central and West Central Alabama as you can see from this radar grab just before 3:40.
Additional strong storms are over Mississippi and will be entering Northwest Alabama soon.
Other storms are in the Birmingham area right now, but they are not especially heavy.
Heavy thunderstorms are over Northeast Alabama tonight. They are dumping torrential rains, producing intense lightning and gusty winds.
They are heaviest over Etowah County, with more heavy rain extending into Marshall and Calhoun Counties. Intense rains are falling just northeast of Gadsden. There may even be some hail there.
A flash flood warning was just issued for parts of Marshall County around Albertville and Boaz.
Everything is moving northeast.
Other showers and storms are over the southern portion of WEst central Alabama down around Demoplis and Thomaston and Pine Hill.
Showers formed late this morning over West Central Alabama, extending back into Mississippi along the leading edge of a southwesterly flow aloft ahead of an upper level disturbance near St. Louis.
The showers extend from southern Tuscaloosa County back through Greene and Hale and into Sumter Counties. The activity extends eastward across South Central Alabama from Dallas County eastward through northern Montgomery and Elmore Counties to Clay, Randolph and Lee Counties. The activity is widely scattered at this time.
The graphic shows heat index values at this hour. They are not quite to the advisory criteria of 105F, but they are close in spots. Note that the 104F at Jasper is a suspect value.
Temperatures are in the middle 90s, ranging from 96F at Anniston to 95F at Calera and Birmingham. The temperature at Tuscaloosa peaked at 95F before nearby showers cooled the air by 10 degrees.
The main lobe of vorticity is pushing through western Mississippi and this hour. It will bring a round of scattered showers and storms to western and northwestern Alabama this evening. Here is the 4km NAM Simulated Radar Reflectivity for 9 p.m. tonight.
The Hurricane Hunters are in Hawaii, but they are not on vacation.
The 53rd Weather Reconnaissance Squadron (Air Force Reserve Hurricane Hunters) have deployed two lanes to Joint Base Pearl Harbor to monitor Hurricane Iselle as it makes landfall tonight and to monitor Hurricane Julio as it passes north of the islands this weekend.
I always love the Google Earth depictions of the Hurricane Hunter missions, especially since they look like a Lite Brite, a toy from some of our childhoods.
But these two storms mean business and the Hawaiian Islands are battening down.
If Iselle makes landfall as a hurricane on the Big Island tonight, it will be the first landfall of a hurricane since Iniki in 1992. Only three storms have made landfall as full hurricanes in Hawaii since 1950.
The big island has not had a direct landfall from a full hurricane since modern records began in 1950.
Here is the forecast track for Iselle, showing landfall between 2-3 a.m. CDT, which is 9-10 p.m. Hawaiian time.
Hurricane warnings are in effect for the big island of Hawaii, with tropical storm warnings for the rest of the islands. Flash flood watches are in effect for all of the islands.
The storm is unusual in that it has battled an environment full of dry air and decent shear to remain a hurricane. Here is an enhanced satellite image of Iselle.
In a bit, we will take a look at the impact being expected in the islands as Iselle approaches and what affects Julio will have over the weekend.
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AFTERNOON UPDATE: Several features of interest this afternoon on the GR Earth map.
…The cumulus field is decent across Central Alabama. It is thinner to the north, where moisture levels are lower and to the south, where morning clouds kept down the heating.
…A few showers had formed in some of the same areas as yesterday. The heaviest was between Vernon and Belk in Lamar county, with others straddling the line between Marion and Lamar Counties. Others were trying to form over southern Winston and northern Walker Counties. Another was over the City of Tuscaloosa. Everything was drifting slowly southeast. Storms will rain themselves out pretty quickly since there is little wind shear.
…Temperatures across Central Alabama were in the upper 80s generally. Birmingham did touch 90F briefly.
…Tropical Storm Bertha is 689 miles south of Birmingham at this hour. It has turned northwestward and will begin to recurve to the north and northeast tonight and Monday. It is no threat to land. Top winds are still 45 mph but some modest strengthening is expected and it will stop just short of becoming a hurricane.
Tropical Storm Bertha is pulling through the southeastern Bahamas late this morning.
It is beginning to make the expected turn to the north that will eventually presage its recurvature away from the United States. The storm is expected to miss Bermuda as well.
It has top winds of 45 mph but is expected to strengthen some later today as it moves over warm water and encounters upper level winds that are a little more favorable for development. It should not reach hurricane intensity (74 mph or higher) though.
It will pass about 200 miles southeast of Cape Hatteras Tuesday morning as it accelerates northeastward. It will pass a couple of hundred miles southeast of Newfoundland Thursday morning then start the trek across the North Atlantic.
A trough of low pressure over the Bahamas (not associated with Bertha) is disorganized and does not appear to be a candidate for development.
The upper level trough over the eastern United States continues to keep temperatures on the cool side in places to our north.
The 57F at Jackson KY yesterday was a record for the August 2nd. Roanoke and Danville VA both had record cool maximums as well with 72F.
Record cool continues across the Arklatex as well, as clouds and showers have kept readings cool the past few days. El Dorado AR and Monroe LA both had record cool maximums again yesterday with 81F and 80F respectively.
The 72F at Monroe on Friday and the 69 at El Dorado were all time record cool highs for August.
Just a few more entries in the old weather record books.