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While we enjoy a nice spring day today, we will be focused on developments to the west of Alabama. SPC maintains a moderate risk of severe weather this afternoon and tonight in the general area from Fort Worth and Waco to the Mississippi River. This includes places like Shreveport, Monroe, Tyler, and Longview. Thunderstorms will become severe, and some of them will have the potential to produce damaging winds and tornadoes as a vigorous upper trough moves out of the Rockies.
TOMORROW: SPC has upgraded the risk to moderate for the southern half of Alabama; the moderate risk is generally along and south of U.S. 80. A slight risk extends northward to the Tennessee border. Here are some forecast parameters from the NAM for Birmingham tomorrow afternoon:
Surface Based CAPE: 319 j/kg
Lifted Index: -1.8
0 to 3 KM Helicity: 385 m2/s2 (down from 772 during the morning when the warm front comes through)
850 mb wind: 46 knots
500 mb wind: 61 knots
200 mb wind: 141 knots
No doubt the greatest instability values will be over the moderate risk area over South Alabama; they really drop off as you go north of I-20.
As mentioned here a number of times, the surface low really doesn’t spin up until it moves northeast of Alabama, and the upper trough is a positive tilt one. But, wind fields are strong, and there there is a decent amount of veering in the lowest 1 km of the atmosphere. If we can get surface dewpoints up into the 60s, and the storms become surface based, there is no doubt we will be dealing with a few severe thunderstorms around here.
TIMING: The models continue to slow everything down just a bit. We might (and probably will) have a few showers or storms with the northward moving warm front tomorrow morning, but it now looks like the main band of showers and storms, and the primary severe weather threat, will come from about 12:00 until 7:00 p.m.
SEVERE WEATHER REMINDERS:
*You can watch our radar anytime on the live stream; just to to the main ABC 33/40 weather page and click on the live stream button. Of course, if we do into wall to wall tornado coverage then that will be on the live stream. Right click on the video box and you can put it in the Real Player, which enables you to resize it anyway you want.
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*As always, we will have frequent updates here on the blog with J.B. and Bill Murray.
SUNDAY/MONDAY: The storms move out Saturday night, and colder air returns Sunday. The clouds could hang tough much of the day, especially east of I-65, and temperatures over Northeast Alabama might have a hard time getting out of the 40s. Most places will have a high only in the low to mid 50s, about 20 degrees below normal for mid-April in Alabama. Then, look out for mid 30s by Monday morning, and the colder valleys across North and Central Alabama will have a chance of frost and a light freeze.
NEXT WEEK AND BEYOND: A weakening system might bring a shower or two by Tuesday night or Wednesday of next week, but the GFS looks drier and drier. We might take that out of the forecast if the 12Z run continues the trend. The next really major system doesn’t show up until April 27 (on the 00Z run).
WEATHER PARTY: Get all the latest weather news over on our sister site, WeatherParty.com. Be sure and register while you are there; you can submit stories and vote on them to determine what is published on the front page.
I will be going a weather program this morning at South Shades Crest Elementary School… then back into the ABC 33/40 Weather office where I will have the next Weather Xtreme video posted by 3:30 this afternoon!
