Stong sea breeze formation and high moisture quantities led to another day of showers and thunderstorms on August 17th. The most active weather primarily focused over portions of the east coast recently impacted by high rainfall.
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 MFL wrote it up.
Stong sea breeze formation and high moisture quantities led to another day of showers and thunderstorms on August 17th. The most active weather primarily focused over portions of the east coast recently impacted by high rainfall. Metro Palm Beach, Miami-Dade, and Broward counties grounds were very saturated from rainfall, so the land was prone to 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 Miami, FL wrote its last area forecast discussion before the first event at Aug 17, 1:24 PM EST, 9 minutes earlier.
Area Forecast Discussion National Weather Service Miami FL 224 PM EDT Thu Aug 17 2023 ...New LONG TERM... .SHORT TERM... (Rest of today through Friday) Issued at 1242 PM EDT Thu Aug 17 2023 Large-scale troughing will be advecting across the eastern half of the CONUS today that extends down through the Carolinas. A shortwave trough becomes enhanced to the south of that large-scale trough base across AL/GA and the Florida Panhandle. A stationary frontal boundary near the FL/GA coast will prevent the troughing from digging further south into the Florida Peninsula, but re-building high pressure over the western CONUS will force the trough offshore while simultaneously attracting positive vorticity and tropical moisture from the south that was formerly a tropical wave. This wave of energy will also advect offshore today into Friday, but will be responsible for more high chances for rain showers and thunderstorms as PWATs will continue to be over 2 inches and likely closer to 2.2. Near-surface flow veers to the SW today as the trough advects eastward, focusing the steadiest rain towards the interior and northern east coast metro areas in Broward/Palm Beach counties. The SW flow will also inhibit how far the east coast sea breeze could penetrate inland with winds from the breeze being closer to due south rather than the usual E/SE flow of the breeze. This further points to higher QPF for the east coast. Overall, primary hazards will be the risk for flooding along the east coast metro plus stronger wind gusts and frequent lightning in the strongest storms. The upper-level ridge will begin to amplify on Friday and shift further to the east, allowing winds to become easterly beginning on Friday which will turn the focus for convection back towards the western interior and west coast. The pressure gradient will be weaker which will keep winds lighter, so expecting the gulf breeze to develop and help increase low-level moisture convergence and thus allowing for convection to become pretty widespread again. Hydro concerns will again be the primary focus as lapse rates and other convective parameters will be too low for severe thunderstorm threats. Temperatures will mostly be in the low 90s today and tomorrow due to increased cloud cover and rain chances. Overnight lows will range from the mid 70s near the lake to near 80 along the coasts. && .LONG TERM... (Friday night through next Wednesday) Issued at 223 PM EDT Thu Aug 17 2023 South Florida will remain under the influence of a weak synoptic flow regime, with expansive ridging of high pressure centered over the TX/OK border, and short-wave troughing further north in the mid-Atlantic region. A remnant easterly wave axis will likely impact the region to kickoff the weekend, with a broad envelope of tropical moisture ahead of this features and it approaches the region for the SE. Saturday morning in particular could be convectively active along the east coast, and activity that develops through Saturday may not be commensurate with diurnal heating/instability, but will rather be driven by steep low-level convergence, and modest forcing for ascent due to latent heat release associated with tropical instability. Again, the main concern will be related to excessive rainfall and perhaps a few strong wind gusts in the form of wet microbursts. Sunday will feature a similar flow regime, albeit with less pronounced low- level convergence and a slight veering out of the SSE. This should allow convection to become more focused over the interior/Lake region, although convective development will still be possible across all South Florida. Thunderstorms should generally remain sub-severe for the latter part of the weekend as well, although a few strong wind gusts cannot be ruled out where mesoscale parameters are best aligned. Early next week will feature the eastward expansion of H500 ridging, such that South Florida is encompassed in the SE quadrant of this feature. This will facilitate the materialization of an east/east-southeast flow regime, which will prevail through much of the early week period. The nature of this steering flow will favor early morning development of showers/thunderstorms along the east coast, with a gradual westward progression towards the interior and west coast by the afternoon/evening hours. Convection should generally be sub-severe through this period as well, owing to an absence of wind shear and robust forcing for ascent. Gusty wind, frequent lightning, and localized flooding will be possible through this period. Temperatures will remain seasonable to seasonably warm through the extended forecast period. Brief periods of cooling can be expected in the presence of rainfall and cloud coverage, while any prolonged suppression of storm activity will result in periods of excessive heat. && .AVIATION... (18Z TAFS) Issued at 1242 PM EDT Thu Aug 17 2023 VFR expected outside of shower and thunderstorm activity, which is expected to increase over land this afternoon. Some restrictions will be possible with storms directly over terminals later today. Winds will be generally SSW but likely shift closer to due south/SSE along the east coast as the sea breeze tries to develop, but otherwise can expect SSW winds. && .MARINE... Issued at 1242 PM EDT Thu Aug 17 2023 Light to moderate south/southwesterly flow prevails today with winds generally no greater than 10-15 kt. By Friday and through the upcoming weekend, winds will back out of the SE/ESE. A plume of tropical moisture may allow for increased thunderstorm activity, especially along the Atlantic waters through Saturday. Wave heights generally remain no greater than two feet, although elevated winds and seas may be possible in association with shower and thunderstorm activity. && .BEACHES... Issued at 1242 PM EDT Thu Aug 17 2023 The rip risk will increase over the weekend as winds become easterly/onshore and increase in speed. However, until then there are no rip concerns. && .PRELIMINARY POINT TEMPS/POPS... Miami 80 92 80 90 / 50 70 50 80 West Kendall 78 94 78 92 / 40 70 50 80 Opa-Locka 79 92 79 90 / 50 70 50 80 Homestead 77 91 78 88 / 30 60 50 80 Fort Lauderdale 79 90 80 89 / 50 60 50 80 N Ft Lauderdale 79 92 80 90 / 50 70 50 80 Pembroke Pines 78 91 79 89 / 50 70 50 80 West Palm Beach 77 91 78 90 / 60 70 50 80 Boca Raton 77 92 79 90 / 50 70 50 80 Naples 79 93 78 94 / 50 80 50 80 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && SHORT TERM...Redman LONG TERM....SRB AVIATION...Redman
Hazardous Weather Outlook National Weather Service Miami FL 920 AM EDT Thu Aug 17 2023 AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676- 181330- Lake Okeechobee-Biscayne Bay- Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM- Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM- Waters from Jupiter Inlet to Deerfield Beach FL from 20 to 60 NM- Waters from Deerfield Beach to Ocean Reef FL from 20 to 60 NM excluding the territorial waters of Bahamas-Glades-Hendry- Inland Palm Beach County-Metro Palm Beach County- Coastal Collier County-Inland Collier County-Inland Broward County- Metro Broward County-Inland Miami-Dade County- Metropolitan Miami Dade-Mainland Monroe-Coastal Palm Beach County- Coastal Broward County-Coastal Miami Dade County-Far South Miami- Dade County- Coastal waters from Chokoloskee to Bonita Beach FL out 20 NM- Coastal waters from East Cape Sable to Chokoloskee FL out 20 NM- Waters from Chokoloskee to Bonita Beach FL from 20 to 60 NM- 920 AM EDT Thu Aug 17 2023 ...Scattered Thunderstorms This Afternoon... ...Localized Flooding Possible This Afternoon... This Hazardous Weather Outlook is for Atlantic coastal waters, southeast Florida, southern Florida, southwest Florida and Gulf of Mexico. .DAY ONE...Today and tonight. Thunderstorms: Scattered showers and thunderstorms will develop today, mainly with a focus over interior and eastern portions of the region. Frequent lightning, strong wind gusts, and localized flooding will be possible within the stronger activity. Excessive Rainfall: Localized flooding will be possible within showers and thunderstorms that develop today, primarily for the east coast. Heat: Heat indices will max out between 102 and 108 degrees this afternoon. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Thunderstorms are possible each day, with chances peaking during the afternoon and early evening hours. Locally heavy rain may lead to instances of street flooding especially during the middle of the week. Heat index values may approach or excess 105-110 degrees for some locations, primarily over the interior and western portions of South Florida. The Rip Current risk may increase into the upcoming weekend over the east coast beaches as easterly winds increase. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed.
Special Weather Statement
National Weather Service Miami FL
143 PM EDT Thu Aug 17 2023
FLZ063-066-171845-
Hendry FL-Glades FL-
143 PM EDT Thu Aug 17 2023
...A strong thunderstorm will impact portions of northwestern Hendry
and Glades Counties through 245 PM EDT...
At 143 PM EDT, National Weather Service meteorologists were tracking
a strong thunderstorm over Port La Belle, or near Labelle, moving
northeast at 20 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Labelle, Moore Haven, Palmdale, Port La Belle, Ortona, Keri and Lake
Hicpochee.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These winds can down small tree limbs and branches, and blow around
unsecured small objects. Seek shelter in a safe building until the
storm passes.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 2684 8111 2679 8094 2660 8139 2703 8154
2703 8134 2704 8133 2703 8133 2703 8127
2712 8127 2712 8117 2713 8117
TIME...MOT...LOC 1743Z 245DEG 19KT 2677 8139
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
MFLThe Miami radar (KAMX), 52 km away, was scanning. The volume nearest the first event began at 18:31 UTC.
5 thunderstorm wind, 2 flood, 1 hail. Local standard time, as filed.
EarthNetworks mesonet at the Seminole Tribe Headquarters reported a wind gust of 59 mph as a strong thunderstorm moved through Hollywood.
Flooding occurred on the Florida Turnpike, near Okeechobee Road/U.S. 27, due to heavy rainfall and poor drainage. A NWS employee reported flooding impacting portions of the southbound lanes.
A trained spotter reported neighborhood streets flooded in Miami Springs due to very heavy rainfall. No impacts to structures was reported. About 4 to 6 inches of rain fell over a 2-3 hour period.
ASOS station KOPF at Opa Locka Airport reported a wind gust 60 mph with the passing of a severe thunderstorm.
Broadcast meteorologist reported several large trees uprooted in Howard Park following the passing of a strong thunderstorm. This park is located just south of a fire station that reported a wind gust of 74 mph. Other tree damage was reported near South Olive Avenue and Avila Rd.
EarthNetworks Mesonet WPBFO West Palm Beach Fire Station reported a wind gust of 74 mph as a severe thunderstorm moved through the area.
Broadcast media reported that a large tree fell on a school bus as a severe thunderstorm moved through the area. There were no injuries at the time of the report. The speed of the wind gust was estimated based on close proximity to where a 74 mph gust was recorded.
A trained spotter reported quarter-sized hail for a duration of five to ten minutes as a severe thunderstorm moved through West Palm Beach.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2023Every state in 2023This day in weather historyWarnings in Florida, August 2023
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: 1131676, 1131689, 1135152, 1131677, 1131675, 1131678, 1131688, 1131687.