A nearly stationary upper level trough was located just east of the Lower Mississippi River. Deep southwest flow east of the trough axis produced a zone of high precipitable water with values near two inches across east Alabama.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BMX wrote it up.
A nearly stationary upper level trough was located just east of the Lower Mississippi River. Deep southwest flow east of the trough axis produced a zone of high precipitable water with values near two inches across east Alabama. Several upper level impulses rotated through the east side of the trough axis and produced periods of heavy rainfall across east Alabama.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Birmingham, AL wrote its last area forecast discussion before the first event at Aug 1, 5:31 AM CST, 2 hours 29 minutes earlier.
Area Forecast Discussion National Weather Service Birmingham AL 631 AM CDT Wed Aug 1 2018 .UPDATE... For 12Z Aviation. && .SHORT TERM... Today through Thursday night. The rainy pattern is set to continue for today and Thursday with periods of showers and storms focused along and east of I-59. An upper-level trough has begun to shear out, but its axis has become nearly stationary near the Mississippi River. A plume of deep southerly moisture in advance of the trough may progress very slowly eastward over the next 48 hours, but the overall setup should not change. The Flash Flood Watch has been expanded slightly westward to encompass areas where moderate to heavy rainfall occurred on Tuesday. This watch now includes the typically flood prone areas in and near downtown Birmingham. Rainfall amounts should generally rain from 1 to 3 inches in the watch area over the next 48 hours, but training storms could cause to 2 to 4 inches to fall in a very short period of time. 87/Grantham .LONG TERM... Friday and Saturday. A weakening upper-level trough will begin de-amplification by Friday, signaling the end of a wetter period to drier/warmer conditions across the overall forecast area. It appears the upper- level jet will remain more active through Saturday with H3 winds in the 40-60 knot range, though mid-level flow is much less, ~10-15 knots. As upper-level dynamics continue to wane, PoPs will do the same as we transition into more summer-like conditions with general isolated/scattered airmass thunderstorms in the afternoon and evening hours. Higher precip probabilities will reside in the southeast for Friday and Saturday as guidance indicates best moisture availability there, though have lowered them a bit Saturday to account for less synoptic lift. Highs Friday are expected to be in the mid to upper 80s, increasing to the 90 degree mark in our southern counties by Saturday as ridging begins to develop in the southeast CONUS. Not expecting severe weather as thermodynamic and wind shear parameters remain negligible, though heavy rainfall could still be a lingering issue in some places as PWATs remain in the 1.8- 2.0" range, especially in the south/southeastern counties. Sunday through Wednesday. Looking into Sunday and early next week reveals an overall trend towards hot and humid weather, with more traditional benign flow aloft. As the ridge nudges its way westward with time, we should see a slight increase in temperatures by Sunday/Monday as heights continue to rise. By then temperatures will top out in the upper 80s to lower 90s, with isolated thunderstorms during peak boundary layer destabilization. Looking into the extended period with global deterministic and ensemble models shows a hint that the upper ridge will breakdown as another upper-level system works its way in from the north. Though too early to reveal specific details, not expecting this to develop as far south as the current one, but have generally increased PoPs for Tuesday/Wednesday particularly in areas north. Overall conditions in the long-term are not concerning as we will transition to more climatologically typical weather for central Alabama. 40/Sizemore && .AVIATION... 12Z TAF Discussion. Continued to trend the ongoing forecast toward the HI-RES ARW for this TAF cycle in regards to TS/RAIN timing and placement. The next wave has begun to move in as scheduled and made only little changes to the forecast. It will be a messy day, aviation wise, so stay aware for multiple amends through the day. As we move into the night, ceilings will drop once again early and it may be a repeat of this morning with showers beginning to expand after 9Z. 16 && .FIRE WEATHER... Showers and thunderstorms are expected through Friday. Relative humidity values will remain higher as good moisture resides throughout the area. Localized fog and low clouds will be possible during the morning hours where rainfall occurs during the previous afternoon and evening. There are no fire weather concerns at this time. 16 && .PRELIMINARY POINT TEMPS/POPS... Gadsden 79 68 82 69 83 / 90 60 60 40 60 Anniston 79 69 81 69 83 / 90 60 70 40 60 Birmingham 81 70 82 70 84 / 80 50 50 40 60 Tuscaloosa 86 71 85 71 85 / 50 40 40 30 60 Calera 80 68 82 70 82 / 90 50 50 40 60 Auburn 77 69 79 69 81 / 90 70 80 50 70 Montgomery 82 71 82 71 84 / 90 60 70 50 70 Troy 80 70 80 70 83 / 90 70 80 50 70 && .BMX WATCHES/WARNINGS/ADVISORIES/... Flash Flood Watch through Thursday evening for the following counties: Autauga...Barbour...Bibb...Blount...Bullock... Calhoun...Chambers...Cherokee...Chilton...Clay...Cleburne... Coosa...Dallas...Elmore...Etowah...Jefferson...Lee...Lowndes... Macon...Montgomery...Perry...Pike...Randolph...Russell... Shelby...St. Clair...Talladega...Tallapoosa. &&
Hazardous Weather Outlook National Weather Service Birmingham AL 250 AM CDT Wed Aug 1 2018 ALZ011>015-017>050-021200- Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee- Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega- Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa- Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon- Bullock-Lee-Russell-Pike-Barbour- 250 AM CDT Wed Aug 1 2018 This Hazardous Weather Outlook is for the counties served by the National Weather Service office in Birmingham. .DAY ONE...Outlook through Tonight. Thunderstorms with heavy rain may produce flash flooding across east Central Alabama, roughly along and east of a line from Selma to Birmingham. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Flash flooding will continue to be a concern across east Central Alabama on Thursday. .SPOTTER INFORMATION STATEMENT... Local activation of storm spotters and emergency management may be needed through Thursday.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
751 AM CDT WED AUG 1 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0700 AM NON-TSTM WND DMG 1 SE YELLOW CREEK FALLS 34.22N 85.72W
08/01/2018 CHEROKEE AL EMERGENCY MNGR
TREE ACROSS ROAD AT COUNTY ROAD 147 AND HWY
411 AND HALE DRIVE IN LEESBURG.
&&The national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
Periods of heavy rainfall produced flooding and several road closures around Weiss Lake, between the towns of Cedar Bluff and Centre. Rainfall amounts were in the 2-4 inch range with locally higher amounts.
Heavy rainfall caused a rockslide which closed part of Highway 431 near Rockledge Road. Several other roads across the county closed due to high water. A home flooded in Southside Community. Rainfall amounts were in the 2-4 inch range with locally higher amounts.
Several roads flooded across far southern Cherokee County in the Spring Garden Community.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alabama in 2018Every state in 2018This day in weather historyWarnings in Alabama, August 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 779055, 779056, 779057.