Big John WEATHER Summary & Discussion
(Issued 4:00 pm Friday May 17th, 2013)
The risk of late-day thunderstorms will be our biggest forecast challenge this weekend with warm moist air already in place. Best risk appears to be late Sunday and Monday, but each of the next six days could see storms pop up. Don't change any plans and watch the sky.
Upper-level disturbance (that caused the Texas twisters Wednesday) will stay north of us, with pouring rains across the Tennessee Valley. In fact, our Atlantic high is still our dominant weather feature.
Normally, you think "high" and you think sunshine and dry conditions. We are on the "backside" of this dome of high pressure with a southwest flow right off the Gulf. There's a favorable moisture source adding to the threat of late-day storms.
And, as we have tried to remind you, it's the sea breeze front moving inland each afternoon that is the primary trigger for late-day storms. The penetrating front should reach west of I-95, but later in the weekend, the front, with a strong offshore flow, may find that more difficult.
So the hour-by-hour forecast: there will plenty of dry periods each day, some patchy fog in rain-areas early, but lots of hazy sunshine through the day. And we will be waiting for the atmosphere to warm to its "convective temperature" which will start that day's storm development.
About 3p, some individual cells will start to pulse, trying to reach to the upper-levels of the atmosphere, dragging some of that energy down to the surface. With sunset, we loose the heat-of-the-day and storms will settle down for the evening with a quiet night overnight.
If you get caught under one of these cells, expect locally heavy rainfall, gusty winds, vivid lightning and even some small hail. Coverage will be limited, in most cases slow-moving, and done shortly. Hopefully we don't interrupt your weekend!
Meteorologist John Wetherbee, CBM
Big Red 11 TV MON-FRI - 5:30pm, 11:00pm; SUNDAY – 6:30pm, 11:00pm
Clear Channel Radio – WTKS AM 1290 & FM 97.7, plus FM @ 98.7 The River
Island Packet Newspapers – www.islandpacket.com/beaufortgazette
On Facebook – www.facebook.com/wtoc11
On You Tube – www.youtube.com/user/BigJohnWeather?feature=guide
On LinkedIn - www.linkedin.com/pub/john-wetherbee-cbm
On TWITTER – www.twitter.com/BigJohnWeather
On the web – weather.wtoc.com
Direct Line: 912.238.8458