Wednesday, March 26, 2014

Warmer weather means spring storms and a chance of severe weather

Following freezing temps metro-wide this morning, nothing near that cold is in the extended forecast that goes into early April. Thus we will assume that winter is finally retreating!  Even "well below normal" temperatures at this point will have a hard time reaching 32 degrees assuming we don't approach it in the next week. So, we bid adieu to one of the coldest winters in some time and turn our attention to the weather spring brings - thunderstorms.  And we won't wait long!

A strong cold front and low pressure system will move from the Plains into the Great Lakes over the next 36 hours, setting the stage for thunderstorms in the metro and even the possibility of severe weather across the Plains and into the western portions of the Mississippi Valley on Thursday afternoon and evening.  In fact, we'll feel the effects of the potency of this system tomorrow in the form of  southerly wind that gusts up to 30-35 mph.  A Wind Advisory is in effect for the entire region.  The Mid-South sits just east of a slight risk for severe weather as the storms will likely be in a weakening state as they move through our area Thursday night, owing to decreasing instability as the sun sets and better atmospheric dynamics as the low goes well to our north.  However, rain and thunder are likely beginning Friday afternoon and into the night (especially before midnight).

A Slight Risk of severe weather exists to our west Thursday and Thursday night. Storms will be weakening as they approach the metro Thursday night.

Expected rainfall between 7pm Thursday and 1am Friday from the NAM computer model. A half inch or so or rain is a reasonable expectation.
Much of Friday should be mainly dry as the cold front sags across the region and upper-level support moves away. However, low pressure will develop to our west along the front and move just south of the Mid-South on Friday night. This will bring another round of likely showers and thunderstorms, mainly after dark and into the wee hours Saturday morning.  The Mid-South is currently under a Slight Risk of severe weather for this time period with the main threat being large hail. While the chance of severe weather is possible, we feel this situation is also borderline, especially with the surface low tracking south of the region. It's something to keep an eye on though.  Unfortunately, the timing couldn't be worse for a sold out exhibition game between the Memphis Redbirds and St. Louis Cardinals at AutoZone Park Friday night!

A Slight Risk of severe weather exists for the Mid-South on Friday night. Hail would be the primary threat and the threat area will be updated several times prior to Friday evening.

Forecast instability from the NAM computer model valid Friday evening at 10pm.  These values are plenty sufficient for thunderstorms across the area.

Forecast rainfall amounts overnight Friday night from the NAM model.  Another half inch of rain is possible on top of Thursday night's rain.
Storms should be out of the area by sunrise Saturday and a dry and not unpleasant weekend is in store with highs in the 60s and lows in the 40s. Next week looks mild overall with 70s likely multiple days and only a slight chance of rain Monday then better chances by mid-week as another springtime weather system approaches. You can find the complete MWN Forecast here or in our mobile apps.

Lastly, readers of this blog are getting the first look at a "draft" version of a new product MWN is developing that will help our readers and followers know when hazardous weather is possible, what the chances are, and how severe the impacts potentially could be. For now, we're calling it our "Memphis Metro Significant Weather Outlook" and today's outlook is posted below. We would LOVE your feedback! It is in testing and we're open to any and all suggestions.  You can drop your comments to us on social media or comment on this blog. We promise to consider all suggestions. This is likely NOT the final way we'll present this outlook, but the one below IS valid for the next 3 days.

Thanks for your input and for reading the blog! We're excited at the prospects of not having to talk about winter weather on this blog again for many months!

--Erik Proseus, MWN Meteorologist

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