Archive for December 16th, 2012
A nice steady rain continues to fall across much of North Central Alabama. Heaviest rain continues to fall from a line near Demopolis to Heflin. Additional showers and thunderstorms are expected to develop along the cold front back off to our west and will be impacting Alabama overnight.
The severe weather threat has lessened across much of North Central Alabama. The latest outlook has trimmed Birmingham and Tuscaloosa out of the risk, but Demopolis, Clanton, Montgomery, Greenville and Mobile remain in it. The rain over our part of the state has help to stabilize the atmosphere. Further south, it hasn’t rained as much and the atmosphere is still unstable. We still expect severe weather across Alabama tonight, as the main upper-level dynamics work through the state. Widespread severe weather is still expected to develop in Louisiana and Mississippi and move towards Alabama.
The graphic below shows rainfall totals are approaching and exceeding 2 inches in potions of Northwest Alabama. Some streams have been reported with high water and the threat for flooding is likely. Flooding could become a threat for many areas in Central Alabama as rainfall continues to fall.
THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED AN
* URBAN AND SMALL STREAM FLOOD ADVISORY FOR MINOR FLOODING OF POOR
DRAINAGE AREAS IN…
LAMAR COUNTY IN WEST CENTRAL ALABAMA…
THIS INCLUDES THE CITIES OF…VERNON…SULLIGENT…MILLPORT…
* UNTIL 445 PM CST
* AT 145 PM CST HEAVY RAIN WAS FALLING ACROSS PORTIONS OF LAMAR
COUNTY. ONE TO TWO INCHES OF RAINFALL HAVE ALREADY OCCURED AND
ADDITIONAL RAINFALL IS EXPECTED. THIS MAY CAUSE MINOR FLOODING IN
POOR DRAINAGE AREAS.
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE…TURN AROUND…DONT DROWN.
Much of Central Alabama remains under a risk for severe weather today. The showers and thunderstorms affecting North Central Alabama are not where our severe weather will be coming from. This is just some initial activity. The better dynamics will come together this afternoon and through the overnight hours for our area. This latest outlook from the SPC keeps much of the Birmingham Metro, down to near Tuskegee and back towards Mobile in the risk. Damaging winds will remain the main threat from severe weather today. Isolated tornadoes will be possible as well, and the threat for flooding exist.
Rain has moved into the Birmingham Metro and across much of Central Alabama. No severe storms anywhere in Alabama right now. The heaviest rain is falling along and north of Interstate 20. Heavier pockets of rain are west of downtown from Adamsville back towards the Samantha community in northern Tuscaloosa County. Another are of heavier rain is east of downtown from near Moody towards Piedmont. The rain should continue to drift off to the southeast and is one of several rounds of showers and storms we can expect today. More storms will develop later this afternoon, and then the main threat of severe weather for us will be overnight tonight. Any and all rain that falls today will be very beneficial as many areas continue to be running rainfall deficits.
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Central Alabama is in for a period of active weather through Monday. This morning we find a lines of thunderstorms lying across the Tennessee River Valley from near Chattanooga to about Columbus, MS. This line was slowly moving eastward while individual storms in the line were moving fairly rapidly northeastward. We also find ourselves in one of those somewhat difficult environments with low CAPE and fairly high shear with slightly better conditions for severe weather resting closer to the Gulf Coast. But SPC has placed a slight risk for Day 1 across the Southeast from about Tuscaloosa southwestward to Baton Rouge and the Louisiana Gulf Coast. For Day 2, the slight risk area shifts eastward stretching from about Dothan northeastward into the southeast corner of North Carolina.
CAPE values indicating instability are generally at or below 500 joules per kilogram with higher values hugging the Gulf Coast. But shear values are relatively high generally along and south of the Interstate 59 corridor. So we face several issues. The first issue is that the weather is likely to come in two waves, the first one coming this morning into the afternoon as one upper short wave kicks out across the area. The second coming later tonight and into the early morning hours of Monday focused south of Birmingham. The threat for today is primarily in two forms, damaging wind and flash flooding. I’m already seeing some potential for flash flooding to develop with the slow progression of the line of storms currently going on. In the second round later tonight, we have to add the threat of isolated tornadoes to the two already mentioned.
This will be a good day to stay indoors and enjoy a good book even though it is going to be mild with temperatures climbing into the mid and upper 60s across the area. Monday will be one of those days where we don’t see much temperature change until the colder air arrives late in the day pushing temperatures rapidly into the 40s – probably after dark.
We get a couple of days off with Tuesday and Wednesday being dry days with cooler temperatures. But the next system should be poised to bring rain and perhaps another round of severe storms to the area on Thursday. Current thinking is that it will be another low CAPE scenario, so it will bear watching. The upper trough with this system is sharper than the current one, so I expect to see colder conditions as we head into the weekend. Colder being a relative term since we will actually drop back to values more typical of the middle of December with lows in the lower 30s and highs in the middle 50s.
Looking into voodoo country, the GFS continues to be consistent with a progressive pattern. Christmas Day looks mild and dry with another weather producing trough around the 27th and yet another one around the 30th.
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James Spann will be back with the next edition of the Weather Xtreme Video. Stay tuned to the Blog for the latest updates as this weather situation unfolds. You can catch my forecast on ABC 3340 at 5 and 10 pm this eveningGodspeed.