Alert archive / Florida / Severe Thunderstorm Warnings in 2018
Severe Thunderstorm Warning 11, NWS Jacksonville, FL
NWS Jacksonville, FL issued this severe thunderstorm warning at Mar 20, 2018, 4:40 PM EDT for Flagler County, Saint Johns County, Florida. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Mar 20, 2018, 4:40 PM EDT (20:40 UTC)
- Expired
- Mar 20, 2018, 5:03 PM EDT
- In force
- 23 min
- Issued by
- NWS Jacksonville, FL
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Flagler County, FL, Saint Johns County, FL
The radar
The Jacksonville radar (KJAX), 94 km from the middle of the area, began a volume at 20:42 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Mar 20, 10:24 AM EDT | Tornado Watch | SPC | 9 hr |
The nearest sounding before it
Jacksonville, FL (KJAX), launched 12:00Z, 8.7 hours before the alert went out and 96 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1315 J/kg
- Mixed-layer CIN
- -48 J/kg
- Mixed-layer LCL
- 494 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 257 m²/s²
- 0-3 km storm-relative helicity
- 271 m²/s²
- Significant tornado parameter
- 2.1
- Supercell composite
- 8.3
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Mar 20, 1:06 PM EDT, 3 hours 34 minutes earlier.
Area forecast discussion, Mar 20, 1:06 PM EDT, 3 hours 34 minutes before
Area Forecast Discussion
National Weather Service Jacksonville FL
106 PM EDT Tue Mar 20 2018
.NEAR TERM (Rest of this afternoon and tonight)...
Torando watches 17 and 18 cover most of SE GA and all of northeast
Florida through 7 pm. Deep southwesterly flow will continue to
bring ample moisture into the region with LLJ at 35 to 40 knots.
The special 14z sounding at Jacksonville continued show very steep
middle lapse rates with very unstable airmass in place with MU
CAPES in the 2000-3000 J/Kg. We are fortunate right now, were we
have not broken our low level cap, but are expected to do so with
further lift and ascension expected with the approach of the short
wave from the Gulf of Mexico. Discrete supercells are anticipated
across the northeast Florida and most of SE GA (particularly east
of highway 301) as deep convection incrementally increases in
intensity/coverage this mid to late afternoon. These storms
should exit the area during the course of the very late afternoon
as the dry slot moves in.
.SHORT TERM (Wednesday and Thursday)...Surface low deepens and
moves off the mid-Atlantic coast as upper level trough dips into
the Southeast U.S. The Intermountain ridge will amplify through
Thursday with a incremental eastward shift, maintaining a
predominantly NNW component across area. Surface high pressure
will build eastward across the Southeast. Dry, breezy/windy and
cooler conditions will occur Wed behind the front then remaining
dry and cooler Thursday. Breezy west northwesterly winds 15-25 mph
with gusts near 35 mph are expected Thursday which will be just
below wind Advisory criteria. High temperatures will be much
cooler, mainly in the low 60s to near 70 both Wednesday and
Thursday, continued cold air advection will keep overnight lows in
the upper 30s inland and mid 40s along the coast.
.LONG TERM (Friday through Tuesday)...Upper level flow will remain
northwesterly through Saturday, and surface flow will shift
around and become light and variable as surface high pressure
moves eastward. Temperatures Friday will warm slightly, and by
Saturday will be back closer to normal (mid 70s for highs, low 50s
for lows). Upper level ridge axis shifts east on Sunday and above
normal temperatures in the low 80s are expected. Another low
pressure system is expected to develop but remain north of the
area. Forecast remains dry until Monday or Tuesday when we could
see a slight chance for precip to make it into far northern zones
and onshore flow developing for a few days.
&&
.AVIATION...Low clouds will continue to produce MVFR cigs this
afternoon with breezy southwest winds. A pre-frontal band of
storms expected to affect the area through the afternoon with
severe storms possible. Have tempo groups for IFR from +TSRA and
gusty winds between 18Z-21Z. Storms should be southeast and east
of the area after around 22Z-23Z. Clear skies on tap tonight.
&&
.MARINE...A band of strong to severe storms will move offshore
late this afternoon. A strong cold front will push across the
waters tonight. A Gale Warning is in effect for the offshore
waters beginning tonight and a Small Craft Advisory is in effect
for the near shore. An extended period of strong winds is expected
until at least early Thursday due to a tight gradient between
strong high pressure building in and a storm system along the Ne
U.S. coast.
Rip Currents: Low risk through Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 45 63 38 63 / 10 0 0 0
SSI 50 63 44 62 / 10 0 0 0
JAX 48 67 41 66 / 10 0 0 0
SGJ 50 68 42 65 / 10 0 0 0
GNV 47 68 39 68 / 10 0 0 0
OCF 48 68 40 68 / 10 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory until 8 PM EDT this evening for Alachua-Baker-
Bradford-Clay-Coastal Duval-Coastal Nassau-Columbia-Flagler-
Gilchrist-Hamilton-Inland Duval-Inland Nassau-Marion-Putnam-
St. Johns-Suwannee-Union.
GA...Wind Advisory until 8 PM EDT this evening for Appling-Atkinson-
Bacon-Brantley-Charlton-Clinch-Coastal Camden-Coastal Glynn-
Coffee-Echols-Inland Camden-Inland Glynn-Jeff Davis-Pierce-
Ware-Wayne.
AM...Small Craft Advisory until 10 PM EDT this evening for Waters
from Altamaha Sound GA to Fernandina Beach FL from 20 to 60
NM-Waters from Fernandina Beach to St. Augustine FL from 20
to 60 NM-Waters from St. Augustine to Flagler Beach FL from
20 to 60 NM.
Gale Warning from 10 PM this evening to midnight EDT Wednesday
night for Waters from Altamaha Sound GA to Fernandina Beach
FL from 20 to 60 NM-Waters from Fernandina Beach to St.
Augustine FL from 20 to 60 NM-Waters from St. Augustine to
Flagler Beach FL from 20 to 60 NM.
Small Craft Advisory from 10 PM this evening to midnight EDT
Wednesday night for Coastal waters from Altamaha Sound to
Fernandina Beach FL out 20 NM-Coastal waters from
Fernandina Beach to St. Augustine FL out 20 NM-Coastal
waters from St. Augustine to Flagler Beach FL out 20 NM.
&&
Cordero/Hess/KennedyIn the hours before
Local storm report, Mar 20, 3:52 PM EDT, 48 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Local storm report, Mar 20, 3:54 PM EDT, 46 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Local storm report, Mar 20, 4:01 PM EDT, 39 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Local storm report, Mar 20, 4:04 PM EDT, 36 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Special weather statement, Mar 20, 4:11 PM EDT, 29 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Special weather statement, Mar 20, 4:34 PM EDT, 6 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>The office that day
Everything else NWS Jacksonville, FL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 20, 3:21 AM EDT | Wind Advisory | JAX | Baker, Bradford, Duval, Flagler, Gilchrist, Nassau and 2 more | 11 hr |
| Mar 20, 3:28 AM EDT | Gale Warning | JAX | 48 hr | |
| Mar 20, 3:28 AM EDT | Small Craft Advisory | JAX | 33 hr | |
| Mar 20, 10:04 AM EDT | Special Weather Statement | JAX | Flagler | 41 min |
| Mar 20, 11:05 AM EDT | Special Weather Statement | JAX | Baker | 40 min |
| Mar 20, 12:18 PM EDT | Special Weather Statement | JAX | Baker | 42 min |
| Mar 20, 12:32 PM EDT | Special Weather Statement | JAX | Alachua, Bradford | 43 min |
| Mar 20, 12:34 PM EDT | Special Marine Warning | JAX | 56 min | |
| Mar 20, 12:39 PM EDT | Special Weather Statement | JAX | Gilchrist | 51 min |
| Mar 20, 12:50 PM EDT | Special Marine Warning | JAX | 55 min | |
| Mar 20, 1:11 PM EDT | Special Weather Statement | JAX | Bradford, Clay, Duval | 49 min |
| Mar 20, 1:14 PM EDT | Special Marine Warning | JAX | 91 min | |
| Mar 20, 1:17 PM EDT | Special Weather Statement | JAX | Columbia, Suwannee | 43 min |
| Mar 20, 1:20 PM EDT | Severe Thunderstorm Warning | JAX | Bradford, Clay, Duval, Saint Johns | 40 min |
| Mar 20, 1:26 PM EDT | Severe Thunderstorm Warning | JAX | Marion | 49 min |
| Mar 20, 1:29 PM EDT | Severe Thunderstorm Warning | JAX | Alachua, Gilchrist, Marion | 46 min |
| Mar 20, 1:51 PM EDT | Severe Thunderstorm Warning | JAX | Alachua, Bradford, Union | 39 min |
| Mar 20, 2:15 PM EDT | Special Weather Statement | JAX | Gilchrist | 45 min |
| Mar 20, 2:17 PM EDT | Special Weather Statement | JAX | Baker, Columbia, Nassau | 43 min |
| Mar 20, 2:19 PM EDT | Special Marine Warning | JAX | 86 min | |
| Mar 20, 2:23 PM EDT | Severe Thunderstorm Warning | JAX | Alachua, Baker, Bradford, Columbia, Gilchrist, Suwannee and 1 more | 52 min |
| Mar 20, 2:26 PM EDT | Severe Thunderstorm Warning | JAX | Baker, Nassau | 34 min |
| Mar 20, 2:28 PM EDT | Special Weather Statement | JAX | Marion | 32 min |
| Mar 20, 2:57 PM EDT | Severe Thunderstorm Warning | JAX | Baker, Duval, Nassau | 48 min |
| Mar 20, 3:18 PM EDT | Special Weather Statement | JAX | Bradford, Clay, Union | 42 min |
| Mar 20, 3:32 PM EDT | Special Marine Warning | JAX | 58 min | |
| Mar 20, 3:35 PM EDT | Special Weather Statement | JAX | Marion, Putnam | 40 min |
| Mar 20, 3:38 PM EDT | Special Weather Statement | JAX | Nassau | 22 min |
| Mar 20, 4:11 PM EDT | Special Weather Statement | JAX | Flagler, Marion, Putnam | 64 min |
| Mar 20, 4:35 PM EDT | Special Marine Warning | JAX | 85 min | |
| Mar 20, 5:57 PM EDT | Special Marine Warning | JAX | 63 min | |
| Mar 19, 8:22 PM EDT | Special Weather Statement | JAX | Wayne | 38 min |
| Mar 20, 1:28 PM EDT | Special Weather Statement | JAX | Atkinson | 47 min |
| Mar 20, 1:47 PM EDT | Severe Thunderstorm Warning | JAX | Atkinson, Bacon, Brantley, Coffee, Pierce, Ware | 43 min |
| Mar 20, 2:13 PM EDT | Severe Thunderstorm Warning | JAX | Appling, Bacon, Pierce, Ware, Wayne | 47 min |
| Mar 20, 2:49 PM EDT | Tornado Warning | JAX | Wayne | 26 min |
| Mar 20, 2:59 PM EDT | Special Weather Statement | JAX | Camden | 46 min |
| Mar 20, 3:16 PM EDT | Special Weather Statement | JAX | Wayne | 29 min |
| Mar 20, 3:41 PM EDT | Special Weather Statement | JAX | Glynn | 19 min |
| Mar 20, 4:34 PM EDT | Special Weather Statement | JAX | Wayne | 26 min |
| Mar 20, 5:07 PM EDT | Special Weather Statement | JAX | Brantley | 38 min |
| Mar 20, 5:28 PM EDT | Severe Thunderstorm Warning | JAX | Brantley, Glynn, Wayne | 32 min |
| Mar 20, 5:59 PM EDT | Special Weather Statement | JAX | Glynn | 46 min |
Nearby
Severe Thunderstorm Warnings in Florida, 2018Every severe thunderstorm warning in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.