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Active Weather Ahead For Alabama

| November 21, 2011 @ 3:41 pm | 8 Replies

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THIS AFTERNOON: The average high for November 21 (for Birmingham) is 63; Birmingham is reporting 74 at 3:00, while Montgomery has soared to 81. But, a strong cold front is over Arkansas, and behind the front Harrison, AR has dropped to 49 degrees. The radar is relatively quiet across North Alabama this afternoon, with just a few patches of light rain over the Tennessee Valley.

Severe storms remain possible west of Alabama tonight over parts of North Texas, South Oklahoma, and Southwest Arkansas ahead of a short wave trough lifting out of the Southwest U.S.

OUR SEVERE WEATHER RISK: SPC maintains the standard “slight risk” of severe weather for almost all of Alabama tomorrow afternoon and tomorrow night. Sure looks like the main threat will come from damaging straight line winds along the squall line tomorrow night, but any storms that form ahead of the line late in the day, mainly after 3:00, will need to be monitored for signs of storm rotation. The overall threat remains in the 3:00 p.m. to 3:00 a.m. time frame, and the highest probabilities of severe weather are over the northern and western counties of Alabama.

For you weather geeks… some severe weather parameters for tomorrow night from the 12Z NAM…

Surface based CAPE 976 j/kg
Lifted Index -3.3
0-3 km SRH (storm relative helicity) 200.4 m2/s2
850 mb wind max (low level jet) 38 knots

Not overwhelming parameters, but certainly supportive of some severe weather. We will be watching the radar closely.

WEDNESDAY: Showers should end early Wednesday morning, followed by gradual clearing. The day will be cooler with a high in the mid 60s.

THURSDAY/FRIDAY: Thanksgiving Day still looks wonderful, with a sunny sky and a high in the 65-69 degree range following a morning low in the low to mid 40s. And, we stay dry on “Black Friday” with a good supply of sunshine and a high not too far from 70.

WEEKEND SEVERE WEATHER THREAT: Let me clearly say we will not be able to get specific about the weekend threat until we get the mid-week system out of here, meaning Wednesday morning. But, the 12Z global models continue to advertise a phased, full latitude long wave upper trough impacting Alabama this weekend with potential for strong to severe storms, followed by much colder weather.

The 12Z runs continue to suggest Alabama’s primary severe weather threat will come Saturday night, after the Iron Bowl in Auburn, but that could change. And, while the dynamics are very impressive, the big question mark involves the thermodynamics. But, I do believe we will have the dual threat of severe thunderstorms and heavy rain, so be watching these discussions over the latter half of the week concerning the threat.

BIG CHANGE TO COLD WEATHER: Following the storms Saturday night, much colder air invades Alabama Sunday and Monday. We might have a hard time getting to the low 50s Sunday, and it looks like our high will be only in the 40s Monday. And, with moisture wrapping around a deep upper low just north of Alabama, we have to wonder if the Tennessee Valley might see their first snow flakes of the season Sunday night or Monday. Take some time to watch the Weather Xtreme video for all the details on these wild weather changes.

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40. We will produce this week’s show tonight at 8:30 p.m. CST… you can listen live via uStream.

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I had a great time today visiting with the first graders at Brent Elementary School in Bibb County… be watching for them on the Pepsi KIDCAM today at 5:00 on ABC 33/40 News! The next Weather Xtreme video will be posted here by 7:00 a.m tomorrow…

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Category: Alabama's Weather

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James Spann is one of the most recognized and trusted television meteorologists in the industry. He holds the AMS CCM designation and television seals from the AMS and NWA. He is a past winner of the Broadcast Meteorologist of the Year from both professional organizations.

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