POSTED: Friday, February 28, 2014 - 4:32pm
UPDATED: Saturday, March 1, 2014 - 9:55am
(KETK) - Tyler, Tx — Our two main forecast models—the GFS and NAM—are having a whirl of a time agreeing. The GFS keeps us with the threat of strong to severe storms, while the NAM brings the cold air into East Texas during the day on Sunday with some wintry precipitation as well. This will be a closely monitored situation.
Let’s look at each model, and then we will give you our thoughts on what we are expecting.
The Storm Prediction Center out of Norman, OK has placed East Texas under a Slight Risk of storms with the main threats being damaging winds, hail, and isolated tornadoes.
After a very warm and humid Saturday, temperatures Sunday morning will be in the 60s and even near 70 degrees by daybreak. There will be plenty of moisture with dew points in low to middle 60s, so some patchy fog is possible. Otherwise, it will be very muggy.
We will likely have cloudy skies by daybreak Sunday. Precipitation looks to start by the lunchtime hour. If we can see breaks in the clouds, this will allow the sunshine to heat us up at the surface and we could see some isolated severe thunderstorms. The main threats will be damaging winds, large hail, and isolated tornadoes.
The wind and tornado threat is due to a change in wind speed and direction as you go up into the atmosphere. Surface winds will be out of the south/southwest at 15-25 miles per hour. At 5,000 feet, winds will be southwest at 45-60 miles per hour. And at 18,000 feet, winds are at 55-70 miles per hour from the west/southwest. The wind direction is veering (clockwise flow) and this small change is why we have an isolated tornado threat—the best chance for isolated tornadoes will be in our Southern counties. The wind speed, however, is increasing—damaging winds with storms on Sunday are likely for all of East Texas.
Here is the GFS output of precipitation of when it moves through.
The GFS also keeps us very warm on Sunday too. The cold front moves through late afternoon and early evening.
The cold air moves in Sunday night and by Monday morning, and it will no doubt be cold. Here are 6AM temperatures from the GFS.
The European forecast model (ECMWF) stays similar to the GFS as far as precipitation and the cold air is concerned.
The NAM model has been trending colder for several runs now, but still has a warm environment ahead of the cold air to support some strong storms.
By daybreak Sunday morning, we look to have temperatures in the low to middle 60s area-wide with dew points in the 60s as well—indicative of very muggy conditions here in East Texas.
As we progress through the morning and afternoon, the cold front really starts to move quickly into our northwestern counties between 9AM and 12 Noon. By 3PM, the front is through most areas with the exception being our southeast counties in Deep East Texas, where your temperatures could be in the middle and upper 70s. With this intense clash of very warm air and cold arctic air, strong to severe storms is very likely.
The concern with the NAM is the cold air moving in so quickly and providing the possibility of wintry precipitation—freezing rain and sleet, behind the cold front. The NAM suggests that temperatures from about Tyler/Longview and areas to the northwest will see temperatures near or below freezing. The NAM has precipitation in our area—especially in the late afternoon/early evening—and it is light.
By daybreak Monday morning, the NAM has us a lot colder than the GFS or than we have previously forecasted. The NAM has some of our areas between 10° and 20° degrees.
Current Forecast—KETK Meteorologists
Between Saturday and Monday morning, KETK Meteorologists are forecasting a significant drop in temperatures. From Saturday’s highs reaching the upper 70s to near 80 degrees, to Monday morning lows between 20-25 degrees, it will be a huge change for East Texas.
As far as Sunday, KETK Meteorologists believe that the cold air will be moving in Sunday afternoon and evening. Out ahead of the cold front, we expect showers and thunderstorms to be prevalent on Sunday with the threat of damaging winds, hail, and the possibility of isolated tornadoes—especially for Deep East Texas.
Monday morning will be very cold. We are forecasting lows well below freezing—in the middle to upper 20s.
Stay with KETK Chief Meteorologist Scott Chesner, Meteorologist Robert Thornton, and Meteorologist Marcus Bagwell for the latest forecast change so you can be informed. We will keep you updated online, on television, on your mobile device, and on our Facebook pages.