Interaction between eastward propagating shortwave over Gulf of Mexico and stationary frontal boundary draped across the north/central Florida peninsula produces a MCS that affects the Nature Coast and central peninsula, producing a damaging wind gust.
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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 TBW wrote it up.
Interaction between eastward propagating shortwave over Gulf of Mexico and stationary frontal boundary draped across the north/central Florida peninsula produces a MCS that affects the Nature Coast and central peninsula, producing a damaging wind gust.
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 Tampa Bay, FL wrote its last area forecast discussion before the first event at Apr 18, 2:45 AM EST, 5 hours 34 minutes earlier.
Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 345 AM EDT Sun Apr 18 2021 .DISCUSSION... A mid level low continues near the Canadian Maritimes through late Mon as a trough over the Mid-Mississippi Valley tracks to the VA/NC coast...with southwesterly flow aloft the area that contains a few weak disturbances tracking east. At the surface a frontal boundary strung across north FL early this morning eases very slowly south...reaching central FL this afternoon then meanders there through Mom. Atlantic high pressure ridges westward with an axis initially the Florida Keys that drops down over Cuba. Scattered showers and a few storms have been ongoing over parts of the Nature Coast this morning along with patchy fog mainly in the south. The fog will increase some in coverage then begin to lift shortly after sunrise. The showers and storms will fill in early in the morning then spread across the central counties this afternoon and evening. Later tonight the boundary wanders south a bit with showers and storms moving into the southern counties. The showers and storms continue Mon across the entire area. Deep moisture, upper level disturbances, lift along the front, and some daytime heating all combine to support high rain chances with localized flooding of streets and low areas possible through Mon. Short term advisories or warnings may be needed. In addition any thunderstorms could reach severe criteria with the greatest threat strong gusty winds and hail. Central locations will be favored today then southern area favored Mon. Tue through late Wed: A mid level low over the upper Great Lakes moves to New England by Wed night as a short wave trough ejects eastward from the southern high plains and dampens out in broad troughing over the eastern US. The frontal boundary remains near central FL until late Wed when it begins to drift into south FL as high pressure builds from the central plains. Deep moisture continues Tue with thunderstorms high rain chances that continue some flooding issues. the storms and rain chances Begin to taper off Wed. From Thu-Sat: Aloft...the eastern US troughing shifts out over the Atlantic as ridging builds from Mexico to south-central Canada then shifts to the eastern states. The ridge slips offshore as a long wave trough moves in from the west. Surface...The frontal boundary dissipates as it exits south FL by late Thu. The central plains high pressure tracks across the eastern states then slips offshore...sprawling down across the Gulf of Mexico region. However the long wave trough forms surface reflection in the northeast Gulf area late Fri/Sat. Thu and Fri will see fair and dry conditions that give way to increasing rain chances Sat as troughiness approaches from the west. && .AVIATION... 18/06Z TAFs. MVFR VSBY/CIGS in SHRA move into northern most aerodromes AFT 10Z and reach SRQ by 14Z. These conditions continue along with VCTS in the afternoon through TAF period. South of SRQ anticipate MVFR/LCL IFR til 14Z. Then VFR with increasing clouds. Light mostly S winds become SW in the afternoon...and gusty in the south. && .MARINE... A frontal boundary slowly moving south over the waters will bring showers and thunderstorms and keep the gradient relaxed until midweek. Then the boundary exits as high pressure builds in from the northwest and north. This high pressure will bring fair dry weather and increasing winds. && .FIRE WEATHER... Moisture rich air in place for the next 3 days or so will preclude low RH concerns and result in showers and thunderstorms with possible heavy rain. Robust transport winds will produce locally high dispersions today. Drier air filtering in for the end of the week could drop RH values to near critical levels in the north. && .Preliminary Point Temps/PoPs... TPA 83 71 78 70 / 60 80 80 70 FMY 88 72 85 71 / 10 50 60 50 GIF 86 69 80 69 / 60 70 80 60 SRQ 83 72 80 69 / 50 70 80 60 BKV 83 67 78 62 / 80 80 80 60 SPG 83 72 78 71 / 60 80 80 70 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && DISCUSSION/AVIATION/MARINE/FIRE WEATHER...09/Rude DECISION SUPPORT...42/Norman
Hazardous Weather Outlook National Weather Service Tampa Bay Ruskin FL 311 AM EDT Sun Apr 18 2021 FLZ043-050-052-056-057-061-139-142-148-149-151-155-160-162-165- 239-242-248-249-251-255-260-262-265-182000- Sumter-Pinellas-Polk-Hardee-Highlands-DeSoto-Coastal Levy- Coastal Citrus-Coastal Hernando-Coastal Pasco- Coastal Hillsborough-Coastal Manatee-Coastal Sarasota- Coastal Charlotte-Coastal Lee-Inland Levy-Inland Citrus- Inland Hernando-Inland Pasco-Inland Hillsborough-Inland Manatee- Inland Sarasota-Inland Charlotte-Inland Lee- 311 AM EDT Sun Apr 18 2021 This Hazardous Weather Outlook is for West Central And Southwest Florida. .DAY ONE...Today and Tonight. ...THUNDERSTORM IMPACT... Thunderstorms are expected today. Thunderstorms that develop will be capable of producing strong gusty winds...locally heavy rains... and frequent deadly lightning strikes. Some of these thunderstorms may produce large hail and damaging wind gusts. ...HEAVY RAIN IMPACT... Locally heavy rainfall is possible. Heavy rain may produce localized flooding of low lying and poor drainage areas as well as the ponding of water on roadways. Motorists should exercise caution. .DAYS TWO THROUGH SEVEN...Monday through Saturday. ...THUNDERSTORM IMPACT... Through Wednesday, thunderstorms are expected. Thunderstorms will be capable of producing strong gusty winds...locally heavy rains... and frequent deadly lightning strikes. Some of these storms may produce large hail and damaging winds on Monday. ...HEAVY RAIN IMPACT... Through Wednesday, locally heavy rainfall is possible. Heavy rain may produce localized flooding of low lying and poor drainage areas as well as the ponding of water on roadways. Motorists should exercise caution. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. Norman
Special Weather Statement
National Weather Service Tampa Bay Area Ruskin FL
833 AM EDT Sun Apr 18 2021
FLZ139-239-181315-
Coastal Levy FL-Inland Levy FL-
833 AM EDT Sun Apr 18 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN LEVY COUNTY UNTIL 915 AM
EDT...
At 832 AM EDT, Doppler radar was tracking a strong thunderstorm near
Chiefland, moving east at 45 mph.
Pea size hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Williston, Chiefland, Bronson, East Bronson, Fowlers Bluff, Andrews,
Manattee Road, Williston Highlands, Fanning Springs, Otter Creek and
Manatee Springs State Park.
LAT...LON 2958 8278 2956 8275 2957 8266 2954 8265
2954 8256 2948 8255 2948 8241 2938 8241
2928 8310 2934 8310 2933 8309 2935 8306
2935 8307 2937 8307 2940 8302 2945 8301
2947 8298 2954 8298 2956 8295 2959 8294
TIME...MOT...LOC 1232Z 260DEG 50KT 2943 8294
TBWPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
909 AM EDT SUN APR 18 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0905 AM HAIL BRONSON 29.45N 82.64W
04/18/2021 E0.70 INCH LEVY FL FIRE DEPT/RESCUE
REPORTS OF DIME SIZE HAIL.
&&
KDThe Jacksonville radar (KJAX), 145 km away, was scanning. The volume nearest the first event began at 13:19 UTC.
1 thunderstorm wind. Local standard time, as filed.
Tree down on power lines reported near Court St. in Bronson.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2021Every state in 2021This day in weather historyWarnings in Florida, April 2021
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: 943512.