Saturday afternoon, July 21st, 2018
Meteorologist: Ryan Stinnett (Twitter: @Ryan_Stinnett)
MORE STORMS THIS AFTERNOON: In the latest convective outlook issued by the SPC, there is a "slight risk" of severe weather over eastern Alabama this afternoon, roughly from Anniston/Oxford, down through Talladega, Prattville, and Evergreen. West of there, a "marginal risk" extends as far west as Huntsville, Cullman, Birmingham, Selma and Mobile. No organized severe storms are forecast for locations west of there. Where storms do develop, damaging winds will be the main threat, along with a threat of large hail and a small threat of a tornado.
The storms over East Alabama this morning laid down a boundary roughly along I-65 this morning. That boundary should act as a focal point for showers and storms to develop as we head into the afternoon. This boundary, is being pushed eastward in a westerly low-level flow as somewhat drier and also sinking air behind the boundary will probably eliminate rain and storm chances for the most part. Ahead of the eastward moving boundary, a few showers and storms will develop. They will affect the most eastern counties of the state.
The main window for severe storms will come from 2PM-8PM this evening. Most locations will see stay dry, as storms today will tend to be rather cellular in nature, and not linear. Be sure and pay attention to both tornado AND severe thunderstorm warnings if they are needed later today.
We don’t expect any widespread flooding issues, but heavier storms could put down one inch of rain in a short amount of time. Keep an eye on the blog for updates through the day!!!
USA BRIEF: A scorching Heat Wave will continue across the southern tier of the country. Temperatures and Heat Indices will reach or easily surpass triple digits, as a ridge of high pressure dominates. Widespread Excessive Heat Warnings and Advisories are in effect, will persist and spread into the Southwest/CA next week. Meanwhile, locally heavy rain will be possible for the OH Valley/Mid-Atlantic/Northeast.
FOR SUNDAY: Tomorrow will be calmer; while a few showers and storms are possible, there is only a marginal risk of severe storms for just the southeast corner of Alabama around Dothan. For North/Central Alabama, it should be a routine summer day with highs in the lower 90s for most locations.
NEW WORK WEEK: There will be sufficient moisture and instability for scattered, mostly afternoon and evening showers and storms each day Monday through Friday, otherwise partly sunny days with high mostly in the upper 80s, below average for late July.
TROPICAL UPDATE: All is calm in the North Atlantic, Caribbean Sea and the Gulf of Mexico and tropical cyclone formation is not expected for the next five days.
WORLD TEMPERATURE EXTREMES: Over the last 24 hours, the highest observation outside the U.S. was 121.6F at Ouargla, Algeria. The lowest observation was -92.0F at Vostok, Antarctica.
CONTIGUOUS TEMPERATURE EXTREMES: The highest observation was 120F at Death Valley, CA. The lowest observation was 33F at Meacham, OR.
WEATHER ON THIS DATE IN 1911: The temperature at Painter, WY, dipped to 10 degrees to equal the record low for July for the continental U.S.
Bill Murray | July 21, 2018 @ 9:17 am
Things are calming for now across North and Central Alabama, but more active weather is going to occur this afternoon.
SEVERE THUNDERSTORM WATCH 297
The NWS in Huntsville has canceled the watch for their counties and the NWS Birmingham allowed their counties to expire at 9 a.m.
Two sets of storms have been affecting Alabama this morning. The tail end of a mesoscale convective system that has been diving southward over Georgia impacted eastern Alabama this morning. The last storms are leaving Chambers and Lee Counties in East Alabama right now. The main impact of this system will be to leave a boundary over East Alabama that storms can exploit later today. Watch for that to be a focus for stronger storms later this afternoon.
A weakening area of storms covers parts of Perry, Autauga, Dallas, Lowndes, Wilcox, Monroe and Conecuh counties at this hour. These storms will move into Southeast Alabama over the next few hours. They are not severe and significant weather advisories have been sufficient for them this morning.
The players are on the field. We have an unusual surface low over Lake Michigan with a cold front near Memphis. That front pushes slowly southeast today and reaches I-20 by midnight tonight. Lots of cloud debris from the morning storms will limit heating in many spots which will reduce instability but the atmosphere should recover enough over the western part of the area for storms. Plenty of wind shear with a 500 millibar jet producing 50-60 knots of bulk shear. A strong 70-knot upper-level jet providing the dynamics. We have boundaries. Hmmm. Should be severe thunderstorms this afternoon and evening ahead of the front.
NEW DAY ONE
The new Storm Prediction Center Day One Severe Weather Outlook is out and it has been cut back substantially. It is now concentrated over East Central and South Alabama. The slight risk (level 2 of 5) includes Anniston, Talladega, Montgomery, Auburn, Greenville, Troy, and Dothan. It also includes a low-end tornado threat south and east of a line from Heflin to Ashville to Montgomery. This includes places like Anniston, Talladega, Alex City, Auburn, Montgomery and Phenix City. So, damaging winds the main threat but can’t rule out a tornado or two.
THANKS FOR NUTHIN’
The mesoscale models are no help right now with the timing and placement of storms. The HRRR sees no evil and hears no evil the rest of the day with no storms developing. Yeah, right. The WRF shows storms developing over eastern counties around 3-4 p.m. with nothing else happening. Wait, there’s a trend here. Maybe no storms develop ahead of the front, except near the boundary over East Alabama.
DID I SAY IT WAS A LOW CONFIDENCE FORECAST?
Well, I am saying it now. We won’t know what’s happening until we see the whites of its eyes. Pay attention to the sky and your trusted weather sources all day. We will have the latest up to the minute information here on the AlabamaWX weather blog all day.
Saturday Morning, July 21st, 2018
Scott Martin (Twitter: @ScottMartinWx)
STRONG TO SEVERE STORMS POSSIBLE ON YOUR SATURDAY
With the atmosphere remaining to be untapped and unstable from a Friday that featured only one shower that briefly formed in Central Alabama, the Storm Prediction Center has the entire Central Alabama area defined in a Slight Risk for Severe Storms on Saturday. We'll have to watch for a couple of MCSs that will be moving in our general direction to see if any actually make it into the area during the morning hours, but we'll also have the possibility of scattered strong to severe storms for anything that forms during the afternoon hours. The good news is that not everyone in the area will see storms.
There will still be plenty of instability available, along with good helicity values, meaning that we could see damaging thunderstorms wind up to 60 or even 70 MPH, large hail up to 1 inch in diameter, and a couple of isolated tornadoes. Afternoon highs should make it up into the lower to mid-90s, but a few spots could stay in the 80s if storms do make it into the area during the early morning hours. Things should calm down for the late night and overnight hours, but a few storms could linger past midnight. Lows will be in the lower to mid-70s.
BACK TO A MORE TYPICAL WEATHER PATTERN ON SUNDAY
Looks like we return to a more usual weather pattern for late July in Central Alabama, as we'll have a good bit of sunshine with a slightly less humid air. We'll have a very slight chance of a few isolated to scattered storms during the afternoon hours, but much of the area will remain dry. Highs will be in the upper 80s to the mid-90s.
THE WORK WEEK AHEAD
This sounds like your typical "rinse and repeat" forecast throughout next week, as we'll see some sun at times, with the standard daily chance of scattered afternoon and early evening showers and storms. Afternoon highs on each day will be in the upper 80s to the lower 90s, while early morning lows will be in the lower to mid-70s. Chances of rain on each day will be between 40-60%.
AN UPDATE ON THE TROPICS
All quiet in the tropics, with nothing expected to form into a tropical depression or storm within the next 5 days.
ON THIS DAY IN WEATHER HISTORY
1987 - Thunderstorms produced severe weather from Utah to North Dakota, spawning a dozen tornadoes in North Dakota. Thunderstorms in North Dakota also produced baseball size hail at Clifford which caused four million dollars damage, and high winds which toppled a couple of eighty foot towers cutting off power to the town of Blanchard.