Alert archive / Georgia / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 255, NWS Jacksonville, FL

December 20, 2018Camden County, Glynn County, Georgia

NWS Jacksonville, FL issued this severe thunderstorm warning at Dec 20, 2018, 11:42 AM EST for Camden County, Glynn County, Georgia. It was in force for 50 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: Dec 20, 2018, 11:42 AM EST (16:42 UTC)
Expired: Dec 20, 2018, 12:32 PM EST
In force: 50 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Camden County, GA, Glynn County, GA

The radar

The Jacksonville radar (KJAX), 66 km from the middle of the area, began a volume at 16:44 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 nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 4.7 hours before the alert went out and 64 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 32 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 532 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 186 m²/s²
0-3 km storm-relative helicity: 265 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 Dec 20, 8:51 AM EST, 2 hours 51 minutes earlier.

Area forecast discussion, Dec 20, 8:51 AM EST, 2 hours 51 minutes before

Area Forecast Discussion
National Weather Service Jacksonville FL
851 AM EST Thu Dec 20 2018

.Update.../through this evening/...

Warm front will move North of the region early this afternoon, as
the cold front enters the Western part of the forecast area. The
cold front will sweep East across area this afternoon. Fairly
widespread rain will lift North with the warm front. A line of
showers and storms is expected to develop along and ahead of the
cold front with isolated strong to severe storms possible. The best
chance for severe weather will generally be South of a line from GNV
to SGJ, with an isolated tornado possible. Areal flooding will
remain possible across much of the forecast area as well, as an
average of 2 to 4 inches, with locally higher amounts falls on
already saturated. Highs will range from 65 to 70 over SE GA and
Suwannee valley of Northeast Florida, to 65 to 70 elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  67  53  58  40 / 100  70  60  10
SSI  68  54  61  40 / 100  80  50  10
JAX  70  55  61  40 / 100  80  50   0
SGJ  74  55  63  40 / 100  90  50   0
GNV  69  54  60  39 / 100  60  60   0
OCF  71  55  61  40 / 100  70  60  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through Friday morning for Alachua-Baker-Bradford-
     Clay-Coastal Duval-Coastal Flagler-Coastal Nassau-Coastal
     St. Johns-Columbia-Gilchrist-Hamilton-Inland Duval-Inland
     Flagler-Inland Nassau-Inland St. Johns-Marion-Putnam-
     Suwannee-Union.

GA...Flood Watch through Friday morning for Atkinson-Charlton-Clinch-
     Echols-Ware.

AM...Small Craft Advisory until 10 AM EST this morning 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-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 until 4 AM EST Saturday 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-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.

&&

23

In the hours before

Local storm report, Dec 20, 11:11 AM EST, 31 minutes before

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Special weather statement, Dec 20, 11:13 AM EST, 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.
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Local storm report, Dec 20, 11:13 AM EST, 29 minutes before

PRELIMINARY LOCAL STORM REPORT
National Weather Service Jacksonville FL
1113 AM EST THU DEC 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1100 AM     TSTM WND GST     4 W MAYPORT             30.39N 81.48W
12/20/2018  M49 MPH          Duval              FL   MESONET

            THE WEATHERFLOW SITE AT BUCK ISLAND MEASURED A PEAK WIND
            GUST OF 49 MPH.

&&

NELSON

Local storm report, Dec 20, 11:15 AM EST, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
National Weather Service Jacksonville FL
1115 AM EST THU DEC 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1056 AM     TSTM WND GST     1 NW MAYPORT            30.40N 81.42W
12/20/2018  M53 MPH          Duval              FL   ASOS

            THE AUTOMATED SURFACE OBSERVING STATION AT NAVAL STATION
            MAYPORT MEASURED A PEAK WIND GUST OF 53 MPH.

&&

NELSON

Special weather statement, Dec 20, 11:32 AM EST, 10 minutes before

Special Weather Statement
National Weather Service Jacksonville FL
1132 AM EST THU DEC 20 2018

FLZ025-031-032-036-037-201715-
Inland Duval FL-Putnam FL-Alachua FL-Bradford FL-Clay FL-
1132 AM EST THU DEC 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN ALACHUA...EASTERN
BRADFORD...NORTHWESTERN PUTNAM...CLAY AND SOUTHWESTERN DUVAL COUNTIES
UNTIL 1215 PM EST...

* At 1132 AM EST, National Weather Service meteorologists were
  tracking gusty showers along a line extending from 7 miles
  northeast of Raiford to 6 miles south of Starke to near Rochelle.
  Movement was northeast at 35 mph.

* Winds in excess of 45 mph possible with these showers.

* Locations impacted include...
  Starke, Interlachen, Keystone Heights, Melrose, Middleburg,
  Hawthorne, Oakleaf Plantation, Florahome, Cecil Field and Melrose
  Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.

&&

LAT...LON 2950 8223 2978 8216 3011 8212 3030 8180
      3003 8172 2955 8180
TIME...MOT...LOC 1632Z 232DEG 29KT 3012 8213 2985 8212 2956 8219

SHASHY

Special weather statement, Dec 20, 11:37 AM EST, 5 minutes before

Special Weather Statement
National Weather Service Jacksonville FL
1137 AM EST THU DEC 20 2018

FLZ024-124-125-201715-
Inland Nassau FL-Coastal Nassau FL-Coastal Duval FL-
1137 AM EST THU DEC 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NASSAU AND
NORTHEASTERN DUVAL COUNTIES UNTIL 1215 PM EST...

* At 1137 AM EST, National Weather Service meteorologists were
  tracking gusty showers near Yulee, or 7 miles southwest of
  Fernandina Beach, moving north at 30 mph.

* Winds in excess of 45 mph possible with these showers.

* Locations impacted include...
  Fernandina Beach and Yulee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. You can also share your report with NWS Jacksonville on
Facebook and Twitter.

&&

LAT...LON 3050 8142 3055 8164 3058 8165 3056 8167
      3074 8170 3073 8165 3073 8162 3072 8161
      3073 8160 3072 8159 3073 8156 3072 8157
      3071 8154 3073 8153 3071 8145 3072 8145
      3072 8142 3057 8139
TIME...MOT...LOC 1637Z 185DEG 28KT 3059 8155

SHASHY

The office that day

Everything else NWS Jacksonville, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 20, 1:49 AM EST	Gale Warning	JAX		50 hr
Dec 20, 7:46 AM EST	Areal Flood Advisory	JAX	Alachua, Marion, Putnam	3 hr
Dec 20, 8:03 AM EST	Special Marine Warning	JAX		87 min
Dec 20, 8:28 AM EST	Special Weather Statement	JAX	Marion	32 min
Dec 20, 9:02 AM EST	Special Marine Warning	JAX		88 min
Dec 20, 9:09 AM EST	Special Weather Statement	JAX	Putnam	36 min
Dec 20, 9:13 AM EST	Rip Current Statement	JAX	Duval, Flagler, Nassau	10 hr
Dec 20, 9:14 AM EST	Special Marine Warning	JAX		61 min
Dec 20, 9:25 AM EST	Areal Flood Advisory	JAX	Bradford, Clay, Flagler, Saint Johns	2 hr
Dec 20, 9:38 AM EST	Special Weather Statement	JAX	Putnam	37 min
Dec 20, 10:02 AM EST	Special Weather Statement	JAX	Saint Johns	28 min
Dec 20, 10:04 AM EST	Special Weather Statement	JAX	Flagler	41 min
Dec 20, 10:24 AM EST	Special Weather Statement	JAX	Duval	36 min
Dec 20, 10:28 AM EST	Special Marine Warning	JAX		62 min
Dec 20, 10:44 AM EST	Special Weather Statement	JAX	Duval	31 min
Dec 20, 10:52 AM EST	Severe Thunderstorm Warning	JAX	Duval, Nassau	38 min
Dec 20, 10:55 AM EST	Severe Thunderstorm Warning	JAX	Duval, Nassau	35 min
Dec 20, 11:25 AM EST	Special Marine Warning	JAX		95 min
Dec 20, 11:32 AM EST	Special Weather Statement	JAX	Clay	43 min
Dec 20, 11:37 AM EST	Special Weather Statement	JAX	Nassau	38 min
Dec 20, 11:40 AM EST	Areal Flood Advisory	JAX	Alachua, Bradford, Clay, Flagler, Marion, Putnam and 1 more	3 hr
Dec 20, 12:12 PM EST	Special Weather Statement	JAX	Clay, Putnam, Saint Johns	48 min
Dec 20, 12:55 PM EST	Special Marine Warning	JAX		65 min
Dec 20, 1:56 PM EST	Special Marine Warning	JAX		64 min
Dec 20, 2:13 PM EST	Wind Advisory	JAX	Baker, Bradford, Duval, Flagler, Gilchrist, Nassau and 2 more	29 hr
Dec 20, 2:39 PM EST	Areal Flood Advisory	JAX	Alachua, Marion, Putnam	4 hr
Dec 20, 3:01 PM EST	Special Marine Warning	JAX		57 min
Dec 20, 11:13 AM EST	Special Weather Statement	JAX	Camden	47 min
Dec 20, 11:56 AM EST	Special Weather Statement	JAX	Wayne	34 min

Nearby

Severe Thunderstorm Warnings in Georgia, 2018 Every 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.