Archive for August 4th, 2012
The Latest on the Tropics
Ernesto is actually weaker this evening. Ernesto has lost a little organization. It is probably running into dry air over the Caribbean.
It still will likely become a hurricane in the next 48 hours as it moves over the western Caribbean. By then, the system will be slowing its forward speed in response to the weakness that is going to be over the northern Gulf Coast. It should reach the Yucatan on Wednesday afternoon and will spend Wednesday night and Thursday morning crossing the peninsula. It will emerge over the southwestern Gulf of Mexico Thursday afternoon.
The global models are in decent agreement that the system will move over the Bay of Campeche and make landfall in Mexico, staying well south of Texas and posing no threat to the northern Gulf Coast. We will be watching.
WHAT ABOUT FLO? Florence has defied the models and the forecasters at the NHC so far. There was talk that the storm would quickly weaken after forming. So far that hasn’t happened, and there isn’t any sign of it happening soon despite dry air surrounding it and relatively cool ocean water. It might actually be stronger than Ernesto now.
The storm has been shoved more westward by high pressure to its north, and that is expected to change as the storm encounters a weakness in the ridge and turns northwestward eventually, carrying it north of the islands.
More Flooding Reports
Other flooding reports from this evening:
…30th Street North and Shuttlesworth Drive
…27th Street and Vanderbilt Road…high standing water with stalled out motorists and others trying to drive through it…please don’t be part of the problem when there is standing water in a roadway…turn around, don’t drown! Road is being blocked.
…31st Street and 8th Avenue North
Birmingham Flooding
In what has become a too familiar scene this week, the Birmingham Fire Department has water rescues in progress in the downtown area.
The heavy rain has ended in the downtown area, but continues from north of downtown to Fultondale, over to the Airport, and up AL-75 to center Point. More heavy rain is in the Fairfield and Hueytown areas. It is all moving slowly west.
Radar estimates indicate that a large part of Birmingham received 1 to 2 inches of rain, with the heaviest from the Civic Center to the Norwood area along I-59.
There is a report of people unable to leave their home because of flooding at 17th Avenue and 33rd Street. This corresponds well with the area of heaviest rain on radar. Motorists stranded at 17th Avenue and 27th Street also.
Scanner reports are courtesy of our Skywatcher John Talbot.
An area flood advisory has been issued for parts of Jefferson County until 9:45. This is a level below a flash flood warning, but please remember, turn around, don’t drown!
The storms will weaken now as the sun sets.
Saturday Afternoon Notebook
…Showers and thunderstorms are most numerous this afternoon over Northwest Alabama into the Tennessee Valley, being influenced by an upper level disturbance that is passing by to the north. The NWS Huntsville just issued a flash flood warning for parts of Lauderdale County.
…Showers and a few storms are plentiful near the Alabama/Georgia border, where moisture levels are higher and there is a weak surface trough.
…The two areas are converging, but the activity should begin to weaken as it “zips” together from the northeast to the southwest, as it encounters less unstable and drier air near I-59. Everything will go downhill as we lose the heating of the day and die out after sunset.
…Nothing organized in sight for tomorrow. An approaching front may help to focus storm development some, but still, activity tomorrow will be scattered and hit or miss.
…Ernesto is stronger (top winds 60 mph). It is south of the Dominican Republic and moving quickly to the west. Forecast thinking hasn’t changed, although the official track forecast has slowed a bit. Still expect it to become a hurricane over the western Caribbean. It should cross the Yucatan Wednesday night and emerge into the southern Gulf Thursday. Only the GFDL and HWRF models carry it northward over the Gulf. The global models are tend to believe it will stay further south. Still believe Ernesto poses no threat to the northern Gulf Coast. But we will be watching.
…Florence continues to confound the forecasters, gaining strength against the odds in the far eastern Atlantic.
Examining the Details
It’s hard to get a good handle on what to expect across Central Alabama on this Saturday afternoon. Let’s examine some of the elements of the weather together:
DRIER AIR, WIDELY SCATTERED STORMS: This morning’s balloon launched from the Shelby County Airport showed really moist conditions below 10,000 feet, with drier air aloft. Precipitable water values were lower across the northern half of the state because of this. This has allowed skies to clear in the I-59 corridor. It looks like we will see afternoon readings reach the lower 90s in this corridor, and that should be sufficient to trigger widely scattered afternoon storms along and southeast of a line from south of Tuscaloosa to Birmingham to Fort Payne.
NORTHWEST/WEST CENTRAL ALABAMA: Clouds were building over areas from Tuscaloosa northward at late morning. Showers were beginning to pop up as well from the Quad Cities into Marion and northern Pickens Counties. This activity is depicted well on the RPM model and seems to be associated with some energy spreading southeast in the wake of dying complex of storms over eastern Kentucky and Tennessee. It should die out by 7 p.m.
MISSOURI DISTURBANCE: An upper level disturbance moving southeastward out of Missouri was triggering more showers and storms this morning. This activity was dying as well, but the tail end of that disturbance could trigger storms later tonight over Northwest Alabama as more unstable air moves into the area.
FLORIDA/GEORGIA TROUGH: Showers and storms associated with the trough of low pressure that we had been talking about over the Bahamas were moving onshore in Northeast Florida and Georgia this morning. This moisture will continue to push northwestward and could affect Southeast Alabama, but should stay southeast of us.
SO, ALL OF THAT TO SAY: The best chance of showers and storms today looks like it may be over northwestern sections of the area, from north of Tuscaloosa to Jasper to Decatur. Storms will be fewer in number in the I-59 corridor. Chances will be less southeast of I-59, although there will be a few showers and storms near the Georgia border. Highs will make the lower 90s in most spots, except where there is significant precipitation and clouds into mid-afternoon.
Showers and storms will die out quickly around sunset, but there could be storms overnight, especially over Northwest Alabama.
