Brian Peters: Atypical severe weather threat for Alabama today

Brian Peters has the forecast for a stormy Saturday in Alabama from Alabama NewsCenter on Vimeo.

WEIRD WEATHER DAY: There’s a rather complicated weather pattern across the Southeast, one we don’t usually see this time of year. We start with a couple of large areas of thunderstorms ongoing this morning, one over north Georgia and one over central Mississippi. Each of these is covered by a severe thunderstorm watch.

The surface pattern featured an anomalous double-low setup, with one surface low near Chicago and a second on the Outer Banks of North Carolina. Each had a front trailing back toward the southwest of each low. Just as unusual for this time of year is a deep trough aloft over the eastern U.S. with a closed upper low over Lake Michigan. CAPE values today will be from 3,000 to 4,000 j/kg along with significant shear, as shown by the Energy Helicity Index with values ranging from 2 to 9 across portions of Alabama, so expect the potential for all modes of severe weather including tornadoes, damaging wind and large hail. Clouds and the presence of numerous storms should hold the highs today in the upper 80s.

THE WEEK AHEAD: The deep trough over the eastern U.S. will remain with us through Wednesday, keeping us somewhat unsettled with a continuation of showers and storms driven primarily by afternoon heating. The good news is that our temperatures should be held down during this period thanks to the upper flow pattern, with lows in the upper 60s and the highs in the upper half of the 80s.

For the latter half of the week ahead, we maintain troughing over the eastern U.S., but that trough is much weaker than we are forecasting for the first half of the week. That means showers and storms will remain daily occurrences as high temperatures again climb to around 90 degrees.

LONG TERM: Looking out into voodoo country, the Global Forecast System remains very bullish on the trough maintaining itself over the eastern U.S. This means no extreme heat. But the upper ridge is forecast to move into the Southeast near the end of the period, around Aug. 5.

TROPICS: All remains quiet across the Atlantic basin, and tropical storm formation is not expected through early next week.

BEACH FORECAST: Click here to see the AlabamaWx Beach Forecast Center page.

WEATHER BRAINS: You can listen to our weekly 90-minute netcast any time on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including meteorologists at ABC 33/40.

Stay weather-aware and weather-safe today for whatever nature has to throw at us. Godspeed.

For more weather news and information from Brian Peters, James Spann and other members of the James Spann team, visit AlabamaWx.

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