A boundary lifting northward over Florida under a mid level trough lingering across the eastern Gulf of Mexico resulted in waves of heavy rainfall, which produced daily rainfall amounts over 4 inches in southern Marion county.
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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 JAX wrote it up.
A boundary lifting northward over Florida under a mid level trough lingering across the eastern Gulf of Mexico resulted in waves of heavy rainfall, which produced daily rainfall amounts over 4 inches in southern Marion county.
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 Jacksonville, FL wrote its last area forecast discussion before the first event at May 21, 3:52 AM EST, 8 minutes earlier.
Area Forecast Discussion National Weather Service Jacksonville FL 452 AM EDT Mon May 21 2018 .UPDATE... We have increased rain chances this morning across much of northeast Florida as a band of convection lifts northward from north central Florida. Categorical POPs were placed in the forecast grids for the St. Johns River basin this morning and across the Suwannee Valley and north central Florida this afternoon. && Previous discussion: ...LOCALLY HEAVY RAINFALL IN THE SUWANNEE VALLEY AND NORTH CENTRAL FLORIDA THIS AFTERNOON... .CURRENTLY... Overnight surface analysis depicts an inverted trough extending from the Florida Big Bend region through the eastern Gulf of Mexico, with a weak mesolow feature moving ashore near Apalachicola. Meanwhile, the axis of Bermuda ridging extends across the southeastern U.S. into the Tennessee Valley. Aloft...a narrow upper trough covers the eastern Gulf of Mexico, while Atlantic ridging remains centered near Bermuda. This stagnant weather pattern is maintaining a deep southerly flow extending from the northwestern Caribbean Sea across the Florida peninsula and into the southeastern U.S., with waves of showers containing locally heavy downpours moving northward. Most activity overnight has been co-located with the mesolow feature over the Florida Big Bend and much of south Georgia, with a broken band of showers moving northward into north central Florida from the Florida peninsula. Abundant mid and high cloudiness blankets our region, with low stratus developing to the east of the mesolow feature and covering much of inland southeast Georgia and the Suwannee Valley. Temperatures as of 07Z were generally in the 70-75 degree range, with dewpoints in the muggy upper 60s to lower 70s. .NEAR TERM /Today and Tonight/... The tropical plume of moisture that is sandwiched in between the mid/upper low to our west and Bermuda ridging to our east will remain in place over our region. Short-term, high resolution guidance indicates that the band of showers moving northward into north central Florida during the predawn hours will impact the Suwannee Valley and coastal northeast Florida through mid-morning as the mesolow/inverted surface trough progresses slowly northwestward into the Florida panhandle. Locally heavy downpours will be possible over the St. Johns River Basin this morning, where totals in excess of one half inch are possible. This activity will progress into interior southeast Georgia by early afternoon, with another round of convection developing along the Interstate 75 corridor early this afternoon and expanding towards the U.S. Highway 301 corridor during the mid to late afternoon hours. Locally heavy downpours will be possible over north central Florida, the Suwannee Valley and our western Georgia counties this afternoon, where widespread totals of one half inch to one inch are expected. Our local pressure gradient will tighten somewhat this afternoon as the Bermuda ridge begins to sink southward over the southwestern Atlantic waters, with breezy onshore winds expected this afternoon. These onshore winds should keep the eastern edge of the rain shield just west of I-95 during the late afternoon hours. Plenty of cloudiness and rainfall today will keep highs in the upper 70s at the coast to the lower 80s inland. The convective band on the east side of the mesolow/inverted trough may continue past sunset over inland northeast Florida and southeast Georgia before waning by midnight. Convergent southeasterly low level winds may develop another band of showers along or east of the I-95 corridor after midnight. Plenty of cloud cover and humidity will keep lows around 70 inland and the lower 70s at the coast, where a southeasterly breeze around 10 mph will continue through the night. .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Wet pattern continues with deep/moist tropical plume of moisture over NE FL/SE GA with Precipitable Water (PWAT) amounts remaining close to 2 inches. This will continue above normal rain chances with numerous showers and storms...mainly during the afternoon and evening hours...and mainly over inland areas of NE FL/SE GA as the Southeast Steering flow continues. Locally heavy rainfall will remain the main threat from storm activity with stronger storms producing quick 1-2 inch rainfalls with isolated higher totals. Storm motion will slow slightly on Wednesday as Wrn Atlc High pressure ridge weakens slightly and heavier storm totals will be possible. Temps will continue near normal levels with Highs in the lower/middle 80s on Tuesday and in the middle/upper 80s on Wednesday. Overnight lows will continue above normal levels in the upper 60s inland and lower 70s along the coast. .LONG TERM /THURSDAY THROUGH SUNDAY/... Long-range models (GFS/EURO) continue to differ on low pressure details in the GOMEX, BUT the overall WET pattern headed into the Holiday Weekend has not changed. The deep/moist tropical plume of moisture will continue from the south with PWATs of 2 inches or more as High pressure ridge continues over the Wrn Atlc and with trof/low pressure over the GOMEX will funnel this moisture northward. For now still expecting Numerous showers/storms daily during diurnal heating with lesser storm activity at night. Locally heavy rainfall will continue to be the main threat and River/Creek basins will likely be reaching near bankfull in some locations due to the long duration of this wet pattern. Highs will generally be in the 80s, with lows in the upper 60s/near 70 degrees. && .AVIATION... Periods of IFR ceilings will be possible at GNV through around 11Z. Periods of IFR visibilities will be possible at VQQ through around 12Z. Otherwise, periods of MVFR ceilings will be possible at the rest of the regional terminals through Monday. A band briefly heavy showers will impact GNV in the 09Z-10Z time frame, possibly resulting in brief IFR visibilities. Showers will likely impact SGJ towards 15Z, the Duval County terminals towards 16Z and SSI towards 18Z. Another band of heavier showers and possibly a few thunderstorms should impact GNV after 17Z, and this activity may linger through around 00Z. VFR conditions may prevail after 19Z at the Duval County terminals and SSI. Surface winds will become east-southeasterly near 10 knots at the regional terminals after 13Z, with speeds near 15 knots with frequent gusts to near 20 knots at the coastal terminals after 17Z. && .MARINE... Small Craft will need to exercise Caution on all waters today, as east-southeasterly winds strengthen to 15-20 knots and seas build to 4-6 feet. Our local pressure gradient will begin to gradually loosen overnight as Bermuda ridging slowly sinks southward while gradually weakening and an inverted surface trough extending from the Florida Big Bend into the eastern Gulf of Mexico moves slowly northwestward. Southeasterly winds should remain just below caution levels overnight, but seas in the offshore waters will remain at Caution levels of 4-6 feet through Tuesday night, while near shore seas subside somewhat to 3-5 feet. Waves of showers and a few thunderstorms will continue to move northward over area waters through midweek. Weak low pressure will then develop near Mexico's Yucatan peninsula by midweek, with this low moving slowly northward towards the central Gulf of Mexico by Friday. A south- southeasterly wind regime is expected to continue from midweek into the weekend, with winds and seas below Caution levels from Wednesday through at least Friday. Rip Currents: A high-end moderate risk is expected today at area beaches due to strengthening east-southeasterly winds and an 8-9 second period southeasterly swell. We will likely consult with northeast Florida lifeguards this morning to determine whether a high risk is warranted for the rest of the day. A moderate risk will continue at area beaches for most of this week as onshore winds prevail. .PRELIMINARY POINT TEMPS/POPS... AMG 82 69 85 67 / 50 40 60 20 SSI 80 71 80 71 / 30 50 60 10 JAX 80 71 83 68 / 60 50 60 10 SGJ 79 72 81 69 / 70 50 50 10 GNV 82 70 85 68 / 60 60 70 30 OCF 82 69 85 68 / 60 40 70 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && Nelson/Hess
The national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
An observer near Lake Weir measured 3.75 inches of rainfall between 5 am and 6:48 am. The 24-hr rainfall was 4.29 inches.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2018Every state in 2018This day in weather historyWarnings in Florida, May 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: 754829.