Showers and thunderstorms developed in association with a cold front moving through the region. Some of these storms produced damaging wind gusts and flash flooding.
Every event with a place to put it. Tap one for its entry below.
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 JAN wrote it up.
Showers and thunderstorms developed in association with a cold front moving through the region. Some of these storms produced damaging wind gusts and flash flooding.
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 Jackson, MS wrote its last area forecast discussion before the first event at Aug 20, 5:20 AM CST, 1 hour 56 minutes earlier.
Area Forecast Discussion National Weather Service Jackson MS 620 AM CDT Mon Aug 20 2018 .UPDATE... Updated for 12Z aviation discussion && .AVIATION... 12Z TAF discussion: Today won't be a good day for flying as showers and storms will move through the region. A line of storms is already entering the Delta and should affect TAF sites there this morning. Additional storms will develop late this morning, and through the afternoon into the evening. These will produce reduced flight categories through the day into the MVFR to IFR range thanks to reduced vis and ceilings. Winds will also be gusty with storms. Outside of storms, VFR conditions should occur. A front will come through later tonight, which will help conditions return to VFR. /28/ && .DISCUSSION... Today and tonight... Active weather will continue today as a stronger, more organized weather system will push through the Mid Mississippi Valley region. As this occurs, it will drop a cold front south toward the ArkLaMiss. Showers and storms will develop ahead of this front by late this morning into early this afternoon and, with continued ample moisture in place as characterized by PW values in excess of two inches, this will bring the potential for additional heavy rainfall. Given the wet antecedent conditions and potential for efficient rainfall, additional flash flooding is possible today. That being said, will continue the mention of this in the limited risk graphic and HWO. CAM guidance suggests that showers and storms will develop across the eastern part of the forecast area late this morning. This activity is not expected to be severe. However, as the front starts to move into the region, there could be a few strong to severe storms. The main limiting factor will be the lack of colder temperatures aloft, which limits how steep the lapse rates will be. Models continue to show rather meager lapse rates and vertical totals. However, given the more organized nature of the system and the fact there is some low to mid level shear present, this will bring potential for a few severe storms, especially in the northwest portion of the forecast area. In this region, we have kept the marginal risk for severe storms with gusty winds being the primary threat. It is possible that more of the Delta could be under a slight risk with later updates. The upper trough will swing across the region Monday night, bringing with it the aforementioned cold front. This will start to usher in a drier airmass into the region, which will result in some cooler/more pleasant weather for a few days this week. Until then, highs today should remain in the upper 80s and lower 90s and lows tonight will once again be in the 70s. With dewpoints remaining in the 70s, it will continue to feel muggy today. /28/ Tuesday through the weekend... By Tuesday morning, a cold front will be draped across ArkLaMiss with some showers and a few thunderstorms out ahead of it. Some convective storms will fire ahead of and along the front as it continues to trek southward through the region. A few strong storms are possible in southern zones as the atmosphere will have a little more time to destabilize ahead of the front. The front should be clear of the ArkLaMiss by Tuesday evening. Northerly flow behind the front will help to bring a cooler, drier airmass into the ArkLaMiss. Pleasant weather for mid/late August standards will prevail through the rest of the work week as the dry airmass remains over the region. Highs on Wednesday and Thursday will remain a few degrees below average with dewpoints remaining in the mid to upper 60s. Early morning low temperatures will fall into the mid to upper 60s across the region. Temperatures and moisture values will begin to increase once again as we get closer to the weekend and the broad high over us begins to shift east of the region. && .PRELIMINARY POINT TEMPS/POPS... Jackson 90 73 91 69 / 51 45 24 9 Meridian 89 74 91 69 / 56 32 42 13 Vicksburg 93 72 91 68 / 53 58 18 7 Hattiesburg 88 74 91 71 / 61 23 55 17 Natchez 90 73 91 69 / 53 49 27 9 Greenville 89 70 88 67 / 60 55 11 4 Greenwood 90 71 88 67 / 58 59 13 4 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && 28
Hazardous Weather Outlook National Weather Service Jackson MS 321 AM CDT Mon Aug 20 2018 ARZ074-075-LAZ007>009-015-016-023-MSZ018-019-025>045-047-048-050- 210830- Ashley-Chicot-Morehouse-West Carroll-East Carroll-Richland- Madison LA-Franklin LA-Bolivar-Sunflower-Leflore-Grenada-Carroll- Montgomery-Webster-Clay-Lowndes-Choctaw-Oktibbeha-Washington- Humphreys-Holmes-Attala-Winston-Noxubee-Issaquena-Sharkey-Yazoo- Madison MS-Leake-Neshoba-Warren-Hinds-Scott- 321 AM CDT Mon Aug 20 2018 This hazardous weather outlook is for portions of southeast Arkansas, northeast Louisiana, central Mississippi, and north central Mississippi. .DAY ONE...Today and Tonight SEVERE THUNDERSTORMS THREAT...Marginal TIMING...Today through Tonight FLOODING THREAT...Limited TIMING...Today A very moist airmass will continue to promote heavy rainfall and flooding in thunderstorms that develop today. Two to three inches an hour rainfall rates will be common where the heaviest storms occur which could easily lead to flash flooding. (https://www.weather.gov/images/jan/graphicast/2.png) Isolated severe thunderstorms will be possible this afternoon into tonight as a cold front moves into the area. Damaging wind gusts and up to quarter size hail will be the main severe weather threats. (https://www.weather.gov/images/jan/graphicast/1.png) .DAYS TWO THROUGH SEVEN...Tuesday through Sunday The probability for widespread hazardous weather is low. .SPOTTER CALL TO ACTION STATEMENT... The activation of storm spotters, HAM radio operators, and emergency management personnel in support of severe weather operations may be needed for portions of the region today through tonight. LAZ024>026-MSZ046-049-051>066-072>074-210830- Catahoula-Tensas-Concordia-Kemper-Rankin-Newton-Lauderdale- Claiborne-Copiah-Simpson-Smith-Jasper-Clarke-Jefferson-Adams- Franklin MS-Lincoln-Lawrence-Jefferson Davis-Covington-Jones- Marion-Lamar-Forrest- 321 AM CDT Mon Aug 20 2018 This hazardous weather outlook is for portions of northeast Louisiana, central Mississippi, east central Mississippi, and south central Mississippi. .DAY ONE...Today and Tonight FLOODING THREAT...Limited TIMING...Today A very moist airmass will continue to promote heavy rainfall and flooding in thunderstorms that develop today. Two to three inches an hour rainfall rates will be common where the heaviest storms occur which could easily lead to flash flooding. (https://www.weather.gov/images/jan/graphicast/2.png) .DAYS TWO THROUGH SEVEN...Tuesday through Sunday The probability for widespread hazardous weather is low. .SPOTTER CALL TO ACTION STATEMENT... The activation of storm spotters, HAM radio operators, and emergency management personnel in support of severe weather operations is not expected through next Sunday. 28 && ...HAZARD LEGEND... *SEVERE THUNDERSTORMS* High...Significant severe thunderstorms are expected. Moderate...Severe storms expected with significant severe weather possible. Enhanced...Severe storms expected. Slight...Severe storms possible. Marginal...Isolated severe storms possible. *FLOODING* Extreme...Confident in significant flooding. Significant...Significant flooding possible. Elevated...Confident in flooding. Limited...Flooding possible. ...USEFUL WEATHER WEB PAGES (URLS)... NWS JAN Home page... https://www.weather.gov/jan Stay Aware, Stay Safe NWS JAN Briefing Page... https://www.weather.gov/jan/safe Latest Weather Briefing... https://www.weather.gov/jan/weather_briefing Tropical page... https://www.weather.gov/jan/srh/tropical?office=jan National Hurricane Center Home Page... https://www.nhc.noaa.gov/ Find NWS JAN on Facebook... https://www.facebook.com/NWSJacksonMS Follow NWS JAN on Twitter... @NWSJacksonMS Follow NWS JAN on Youtube... https://www.youtube.com/user/NWSJacksonMiss ...ADDITIONAL URLS FOR SEVERE WEATHER ISSUES... Storm Prediction Center (SPC)... https://www.spc.noaa.gov/ Meso Analysis... https://www.spc.noaa.gov/exper/mesoanalysis/ Day 1 through 3 Outlooks... https://www.spc.noaa.gov/products/outlook/ Storm Reports... https://www.spc.noaa.gov/climo/online/ ...ADDITIONAL URLS FOR FLOODING ISSUES... Current Watches and Warnings... https://www.weather.gov/jan/safe_HeavyRain Observed Precipitation Images... https://www.weather.gov/jan/precipmaps River Forecast Center... https://www.weather.gov/lmrfc/ Significant River Flood Outlook... https://www.wpc.ncep.noaa.gov/nationalfloodoutlook/index.html Day 1 through 3 Excessive Rainfall... https://www.wpc.ncep.noaa.gov/qpf/excess_rain.shtml Excessive Rainfall Discussion... https://www.wpc.ncep.noaa.gov/discussions/qpferd.html Day 1 through 7 QPF... https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml QPF Discussion... https://www.wpc.ncep.noaa.gov/discussions/qpfpfd.html
The Jackson/Brandon,MS radar (KDGX), 161 km away, was scanning. The volume nearest the first event began at 13:14 UTC.
13 thunderstorm wind, 2 flash flood. Local standard time, as filed.
Numerous streets were flooded in downtown Greenville, and 1-3 inches of rain collected in the Greenville courthouse parking lot.
There was significant flooding on the campus of Delta State University. There was 18 inches of water on one street as pumps could not keep up with the rainfall rates from the storms.
Trees and power lines were blown down in Drew.
One tree was blown down across a road in northern Grenada County.
A tree was blown down on a power line along Highway 1 near the Highway 12 intersection.
A tree was blown onto a house along Old Highway 61 just south of Arcola.
A tree was uprooted and fell across a power line on North 1st Street.
Trees and power lines were blown down in Indianola.
Trees were blown down in Inverness.
A tree was blown down along US 49 South at the Big Black River bridge.
A tree was blown down along Ingram Road.
Trees were blown down in eastern Grenada County.
A tree was blown down and blocked the intersection of Highways 17 and 51.
A tree was blown down on Stump Bridge and Goodloe roads and blocked one lane.
A tree and power lines were blown down and blocked the intersection of Rocky Hill and Cook Cobb roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Mississippi in 2018Every state in 2018This day in weather historyWarnings in Mississippi, 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: 772554, 772553, 769233, 769213, 769211, 769208, 769203, 769178, 769176, 769174, 769169, 769165, 769163, 769162, 769160.