Alert archive / Florida / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 112, NWS Jacksonville, FL

July 31, 2013Nassau County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Jul 31, 2013, 2:20 PM EDT for Nassau County, Florida. It was in force for 40 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
Jul 31, 2013, 2:20 PM EDT (18:20 UTC)
Expired
Jul 31, 2013, 3:00 PM EDT
In force
40 min
Issued by
NWS Jacksonville, FL
Area
Storm-based polygon

County Nassau County, FL

The radar

The Jacksonville radar (KJAX), 16 km from the middle of the area, began a volume at 18:22 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, 6.3 hours before the alert went out and 14 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-pSkew-T log-p diagram, Jacksonville, FL at 12:00Z on 2013-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1861 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jacksonville, FL at 12:00Z on 2013-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1861 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
685 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
16 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 Jul 31, 2:20 PM EDT, 0 minutes earlier.

Area forecast discussion, Jul 31, 2:20 PM EDT, 0 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
220 PM EDT WED JUL 31 2013

.SHORT TERM...
SHORTWAVE TROF WILL MOVE ACROSS THE AREA THROUGH THE
EVENING...PRODUCING NUMEROUS SHOWERS AND T-STORMS ESPECIALLY
ACROSS EASTERN PART OF FORECAST AREA. ALSO EXPECTING TO SEE BAND OF
SHOWERS/T-STORMS OVER CENTRAL GA MOVE EAST ACROSS SE GA THROUGH THE
EVENING...SO HAVE LIKELY POPS THERE AS WELL. ACTIVITY SHOULD DECREASE
AFTER MIDNIGHT...AND HAVE SHOWN TREND OF DECREASING HOURLY POPS.

FOR WED...WEAK TROF ALOFT STILL OVER THE AREA...ANTICIPATING SCATTERED
TO NUMEROUS AFTERNOON SHOWERS/T-STORMS...BEST COVERAGE EXPECTED
OVER OUR EASTERN COUNTIES WITH SEA BREEZE. WITH MORE CLOUD COVER OVER
AREA...GOING WITH HIGH TEMPS AROUND 90 INLAND, MID/UPR 80S COAST.

.LONG TERM...

THURSDAY-SATURDAY...COLD FRONT WILL CONTINUE TO MOVE SOUTH TOWARDS
THE  AREA. A MOIST AND UNSTABLE SW FLOW AHEAD OF IT WILL LEAD TO
SCATTERED TO NUMEROUS MAINLY AFTERNOON AND EARLY EVENING STORMS. THE
EXCEPTION IS THAT THERE WILL BE LESS COVERAGE OF STORMS ACROSS SE GA
ON FRIDAY AND SATURDAY AS DRIER AIR BEGINS TO MOVE INTO THERE.
HOWEVER...MAX TEMPS THERE WILL WARM TO SLIGHTLY ABOVE CLMO.

SUN THROUGH WED AN UNSETTLED PATTERN DEVELOPS AS MEAN LAYER TROUGHING
AND HIGH MOISTURE CONTENT (PWATS OVER 2-2.25 INCHES) POSITION AND LINGER
OVER THE REGION. EXPECT PREVAILING SW FLOW THROUGH THE PERIOD WHICH
WILL BRING A DOMINATE WEST COAST SEA BREEZE REGIME. WILL CONTINUE TO
CAP RAIN CHANCES FOR ALL AREAS AROUND 50%...BUT AS THE DAYS NEAR SUSPECT
HIGHER RAIN CHANCES OF 6O-70% MAY BE NEEDED AS TIMING AND FEATURES BECOME
BETTER RESOLVED.

TEMPS WILL HOVER AROUND CLIMO VALUES WITH HIGHS IN THE LOW/MID 90S AND
MUGGY NIGHTS WITH LOWS IN THE LOW/MID 70S.

&&

.AVIATION...VFR CONDITIONS OUTSIDE OF AFTERNOON/EVENING SHRA/TSRA.
POTENTIAL FOR GUSTY WINDS AROUND STRONGER TSRA. BEST CHANCE OF TSRA
IN THE 18Z-00Z TIMEFRAME AT TAF SITES. SHOULD SEE COVERAGE DECREASE
AFTER 00Z. HAVE VCTS UNTIL ABOUT 04Z.

&&

.MARINE...NO HEADLINES. MAIN CONCERN WILL BE ISOLATED STORMS NEAR
SHORE.

RIP CURRENTS: LOW TO MODERATE RISK OF RIP CURRENTS THROUGH THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  72  89  72  93 /  70  30  30  30
SSI  75  86  76  88 /  70  60  50  30
JAX  73  89  73  91 /  70  60  50  40
SGJ  74  87  73  88 /  30  60  50  40
GNV  73  89  72  91 /  50  40  40  40
OCF  73  89  72  91 /  50  60  40  50

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.

&&

WOLF/PETERSON/
Hazardous weather outlook, Jul 31, 10:32 AM EDT, 3 hours 48 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSONVILLE FL
1032 AM EDT WED JUL 31 2013

AMZ450-452-454-470-472-474-FLZ020>025-030>033-035>038-040-
GAZ132>136-149>154-162>166-010845-
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-
FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-
ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM-
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-
FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE-HAMILTON-
SUWANNEE-COLUMBIA-BAKER-NASSAU-DUVAL-UNION-BRADFORD-CLAY-ST JOHNS-
GILCHRIST-ALACHUA-PUTNAM-FLAGLER-MARION-COFFEE-JEFF DAVIS-BACON-
APPLING-WAYNE-ATKINSON-WARE-PIERCE-BRANTLEY-INLAND GLYNN-
COASTAL GLYNN-ECHOLS-CLINCH-CHARLTON-INLAND CAMDEN-COASTAL CAMDEN-
1032 AM EDT WED JUL 31 2013

...RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE
REGION...

...MODERATE RISK OF RIP CURRENTS NORTHEAST FLORIDA BEACHES TODAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST FLORIDA...
SOUTHEAST GEORGIA AND THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT...

SCATTERED TO NUMEROUS AFTERNOON AND EVENING THUNDERSTORMS ARE
EXPECTED. A FEW OF THESE STORMS MAY BE STRONG WITH FREQUENT
LIGHTNING...TORRENTIAL DOWNPOURS...AND GUSTY WINDS. OVER THE
NEARSHORE COASTAL WATERS...A FEW STORMS ARE EXPECTED AND MAY
PRODUCE GUSTY WINDS UP TO 35 KNOTS IN THE LATE AFTERNOON.

A MODERATE RISK OF RIP CURRENTS ANTICIPATED AT NORTHEAST FLORIDA
BEACHES DUE TO INCREASED EASTERLY SWELLS. FOR MAXIMUM SAFETY...
ALWAYS SWIM WITHIN SIGHT OF LIFEGUARDS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

NUMEROUS THUNDERSTORMS ARE EXPECTED ON THURSDAY. A FEW OF THESE
STORMS MAY BE STRONG WITH GUSTY WINDS AND HEAVY DOWNPOURS. AN
ISOLATED SEVERE STORM WILL ALSO BE POSSIBLE.

SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED EACH
DAY FRIDAY THROUGH TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT REQUESTED AT THIS TIME.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE
IN JACKSONVILLE WEBSITE ON THE INTERNET AT WEATHER.GOV/JAX.

In the hours before

Special weather statement, Jul 31, 1:48 PM EDT, 32 minutes before
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Special weather statement, Jul 31, 1:50 PM EDT, 30 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
150 PM EDT WED JUL 31 2013

GAZ166-311830-
COASTAL CAMDEN-
150 PM EDT WED JUL 31 2013

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR SOUTHEASTERN
CAMDEN COUNTY FOR STRONG WINDS...SMALL HAIL AND EXCESSIVE LIGHTNING
VALID UNTIL 230 PM EDT...

AT 151 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG
THUNDERSTORMS CENTERED 5 MILES WEST OF KINGS BAY BASE...MOVING
NORTHEAST AT 10 MPH. THESE STRONG THUNDERSTORMS WILL ALSO AFFECT
AREAS AROUND ST. MARYS...HARRIETTS BLUFF...KINGS BAY BASE...DUNGENESS
AND CUMBERLAND ISLAND THROUGH 230 PM EDT. HAIL UP TO THREE QUARTER
INCH IN DIAMETER...EXCESSIVE CLOUD-TO-GROUND LIGHTNING AND GUSTY
WINDS OF 45 TO 55 MPH CAN BE EXPECTED ALONG WITH POSSIBLE MINOR
DAMAGE. HEAVY RAINFALL WILL PRODUCE PONDING OF WATER ON ROADWAYS AND
MINOR FLOODING OF LOW-LYING AREAS.

REPORT DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY OR YOUR COUNTY
EMERGENCY MANAGEMENT.

LAT...LON 3080 8145 3075 8145 3072 8144 3072 8148
      3072 8149 3072 8153 3071 8154 3072 8160
      3072 8161 3085 8167 3096 8147 3084 8141
TIME...MOT...LOC 1751Z 241DEG 7KT 3078 8159

PETERSON
Special weather statement, Jul 31, 2:15 PM EDT, 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
215 PM EDT WED JUL 31 2013

FLZ024-311900-
NASSAU-
215 PM EDT WED JUL 31 2013

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR CENTRAL AND
EASTERN NASSAU COUNTY FOR STRONG WINDS AND EXCESSIVE LIGHTNING VALID
UNTIL 300 PM EDT...

AT 215 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM CENTERED 9 MILES WEST OF YULEE...MOVING EAST
AT 5 MPH. THIS STRONG THUNDERSTORM WILL ALSO AFFECT AREAS AROUND
YULEE...AND CROSS INTERSTATE 95...THROUGH 300 PM EDT. EXCESSIVE
CLOUD-TO-GROUND LIGHTNING AND GUSTY WINDS OF 45 TO 55 MPH CAN BE
EXPECTED ALONG WITH POSSIBLE MINOR DAMAGE. HEAVY RAINFALL WILL
PRODUCE PONDING OF WATER ON ROADWAYS AND MINOR FLOODING OF LOW-LYING
AREAS.

REPORT DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY OR YOUR COUNTY
EMERGENCY MANAGEMENT.

LAT...LON 3058 8160 3059 8161 3058 8162 3059 8162
      3058 8165 3057 8180 3072 8181 3073 8162
      3072 8161 3073 8160 3069 8154 3058 8154
TIME...MOT...LOC 1815Z 278DEG 5KT 3064 8172

WOLF

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 1:48 PM EDTSpecial Weather StatementJAXNassau42 min
Jul 31, 2:15 PM EDTSpecial Weather StatementJAXNassau45 min
Jul 31, 2:24 PM EDTAreal Flood AdvisoryJAXBaker, Nassau2 hr
Jul 31, 2:26 PM EDTSpecial Weather StatementJAXSuwannee49 min
Jul 31, 3:04 PM EDTAreal Flood AdvisoryJAXClay, Duval, Nassau, Saint Johns116 min
Jul 31, 3:06 PM EDTSpecial Weather StatementJAXColumbia39 min
Jul 31, 3:29 PM EDTSevere Thunderstorm WarningJAXColumbia46 min
Jul 31, 3:35 PM EDTSpecial Weather StatementJAXClay40 min
Jul 31, 3:46 PM EDTSpecial Weather StatementJAXGilchrist44 min
Jul 31, 4:02 PM EDTSevere Thunderstorm WarningJAXAlachua, Bradford, Columbia, Union43 min
Jul 31, 4:22 PM EDTAreal Flood AdvisoryJAXClay, Saint Johns113 min
Jul 31, 4:29 PM EDTSpecial Weather StatementJAXAlachua46 min
Jul 31, 4:44 PM EDTSevere Thunderstorm WarningJAXAlachua, Marion46 min
Jul 31, 5:00 PM EDTAreal Flood AdvisoryJAXAlachua, Marion2 hr
Jul 31, 5:38 PM EDTSpecial Weather StatementJAXPutnam52 min
Jul 31, 5:39 PM EDTFlash Flood WarningJAXAlachua111 min
Jul 31, 5:52 PM EDTSpecial Weather StatementJAXMarion53 min
Jul 31, 6:52 PM EDTSpecial Weather StatementJAXFlagler23 min
Jul 31, 7:31 PM EDTTornado WarningJAXHamilton, Suwannee29 min
Jul 30, 8:11 PM EDTSpecial Weather StatementJAXEchols34 min
Jul 31, 1:50 PM EDTSpecial Weather StatementJAXCamden40 min
Jul 31, 1:54 PM EDTAreal Flood AdvisoryJAXCamden2 hr
Jul 31, 2:10 PM EDTAreal Flood AdvisoryJAXCamden2 hr
Jul 31, 2:39 PM EDTSpecial Weather StatementJAXCamden51 min
Jul 31, 4:15 PM EDTSpecial Weather StatementJAXWare45 min
Jul 31, 5:15 PM EDTAreal Flood AdvisoryJAXBrantley, Pierce, Ware2 hr

Nearby

Severe Thunderstorm Warnings in Florida, 2013Every severe thunderstorm warning in 2013

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.