Saturday, March 13, 2021

Spring has arrived - and so have severe weather chances

Spring has sprung across the Mid-South! Temperatures have warmed considerably from a month ago and meteorologists have shifted the mindset from looking for snow in the extended forecast to watching for severe weather chances.

A recent spell of highs in the 70s has been the lengthiest such streak in four months, welcome news for those that grew weary of counting the days until we got back above freezing! This weekend we'll be dealing with a series of fronts that will bring rounds of precipitation to the area.

This weekend

This (Saturday) morning, a cool front has slipped to our south. Post-frontal showers are moving east over northern AR and west TN this morning, bringing some rain to portions of the metro. With upper level energy departing, rain chances drop this afternoon to the "chance" category with most areas dry as high temperatures climb through the 60s. A northeast wind and lingering clouds may be enough to stop our 70-degree streak at five unless we can eek out an extra degree or two today.

Tonight, the front starts to lift north a bit and a stray shower or two are possible, otherwise it'll be mild with temperatures only falling to the upper 50s. There will be one less hour for temperatures to drop tonight, as we press our clocks forward into Daylight Saving Time! Don't forget to check your batteries in smoke detectors and weather radios as well!

Sunday starts cloudy, obscuring the delayed sunrise that occurs at 7:12am. However, the front in Mississippi lifts to our north, wind shifts to the southeast, and temperatures respond accordingly, rising back into the mid 70s. The huge storm system to our west - the one responsible for all the snow in Colorado and Wyoming and severe weather in the southern plains today - moves in our direction as well. A couple of daytime showers are possible Sunday, but most precipitation holds off until overnight. A bonus: daylight lingers past 7pm!

A very busy weather map for Sunday with snow and freezing precipitation in the west and north, rain and thunderstorms in the south. (NOAA/WPC)

Sunday night

On Sunday night, that storm system to our west approaches, but in a weakening state. Rain becomes likely overnight, particularly after midnight, with some thunderstorms also possible. The Storm Prediction Center (SPC) currently has areas from Memphis southwest into the Delta highlighted for a Slight Risk (level 2) of severe weather and the rest of the region in a Marginal (level 1) Risk. The contributors to this risk are strong wind (particularly aloft) and wind shear. The main limiting factor is a lack of unstable air. I'd be more worried if it were arriving in the mid to late afternoon. 

The severe weather outlook for Sunday includes a Slight Risk (level 2/5) for yellow areas in the upper left, including the city of Memphis. The primary risk is strong wind (lower right - 5-15% within 25 miles), while a small risk of a tornado exists as well (upper right - 2-5% chance). (SPC via Pivotal Weather)

A few storms could bring strong wind gusts, mainly between midnight and 6am. An isolated tornado can't be ruled out due to the wind shear, but chances appear fairly slim. Heavy rain is also expected in possible bands or a line overnight.

Early next week

By Monday morning, the system will be pushing east and sunshine will break out across the region. With the front's origins in the Pacific rather than Canada, mild weather follows with highs back into the mid 70s and a decent breeze. It'll be a great spring day! Tuesday will be similar temperature wise, although high clouds will be streaming overhead in advance of the next weather-maker.

Wednesday - severe storms?

That next system, a more potent low pressure center moving by to our north and cold front poised to slice through the Mid-South, arrives Wednesday. Timing is still a bit uncertain, as are the details on the low track and potential instability, but we'll be watching this one closely. SPC has already highlighted a large area, including the metro, for a risk of severe weather. Given the likely daytime arrival, we'll have more warm air to work with. Upper and mid-level dynamics look favorable for severe weather as well. We'll have more on it, but stay weather aware on Wednesday and be prepared to adjust plans as necessary. 

Another, likely more potent, risk of severe storms exists on Wednesday, as shown by SPC above, for a much larger area than Sunday. Details are still TBD. (Pivotal Weather)

Late next week

Drier weather settles in behind Wednesday's departing system with cooler temperatures as well. There is a chance we could see a couple showers Thursday if the upper level low associated with Wednesday's system moves overhead, but skies clear heading into the weekend with slightly below average temperatures that moderate with time.

So, to summarize - minimal severe weather chances Sunday night, the potential for more impactful severe storms on Wednesday, and change your clocks tonight! Happy Spring!

Erik Proseus
MWN Meteorologist

Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

No comments: