Stormy Wednesday Across Much of US

5/02/2012 forecast No Comments

Most of the heavily populated areas east of the Rocky Mountains will see active weather on Wednesday, with a severe risk across much of the upper Midwest stretching eastward into the Mid Atlantic, with general thunderstorms expected along the Gulf Coast.

Current SPC severe weather outlook. This image updates as the SPC updates it on their site.

The storms from the upper Mississippi Valley eastward through northern Illinois will provide all modes of severe weather -- tornadoes, large hail, and damaging winds. The tornado threat will occur mainly in the evening as the low-level jet ramps up and provides enough vertical wind shear to allow storms to rotate. The models are predicting a massive amount of instability in this area, and with thunderstorm expected to initially be supercellular, tornadoes and very large hail are possible in the moderate (red) risk zone. Later in the evening, the supercells will congeal into a line, transitioning into a damaging wind threat.

Further east towards the Mid Atlantic, the main severe weather threat will be damaging winds and some sporadic hail.

Off to the south near the northern Gulf Coast, a trough will provide enough lift to fire off heavy rain and thunderstorms during the day on Wednesday and lasting through some of Thursday. The HPC predicts upwards of an inch of rain centered across Alabama, with higher amounts possible in any heavy thunderstorms that get going.

Parts of the Pacific coast are also subject to heavy rain Wednesday-Thursday as a storm system makes its way ashore.

HPC forecast rainfall from 1AM CDT Wednesday until 1AM CDT Friday.

Temperatures will be above average for a large section of the country, with 80s and 90s dominating almost everyone from the Rockies to the Atlantic, save for the northeast where clouds and drizzle will keep temperatures on the chillier side.

Forecast high temperatures on Wednesday from the National Weather Service.

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