Alert archive / Florida / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 234, NWS Jacksonville, FL

July 31, 2011Marion County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Jul 31, 2011, 3:53 PM EDT for Marion County, Florida. It was in force for 52 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, 2011, 3:53 PM EDT (19:53 UTC)
Expired
Jul 31, 2011, 4:45 PM EDT
In force
52 min
Issued by
NWS Jacksonville, FL
Area
Storm-based polygon

County Marion County, FL

The radar

The Jacksonville radar (KJAX), 146 km from the middle of the area, began a volume at 19:56 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, 7.9 hours before the alert went out and 148 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 2011-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2510 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 2011-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
2510 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
952 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
20 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, 2:30 PM EDT, 1 hour 23 minutes earlier.

Area forecast discussion, Jul 31, 2:30 PM EDT, 1 hour 23 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
230 PM EDT SUN JUL 31 2011

.SHORT TERM...CONVECTIVE TEMPERATURE HAS BEEN REACHED WITH DOPPLER
RADARS SHOWING SHOWERS AND THUNDERSTORMS QUICKLY FORMING ACROSS
NORTHEAST FLORIDA WITH LIMITED COVERAGE NOTED ACROSS SOUTHEAST
GEORGIA. FOR THE REMAINDER OF THIS AFTERNOON...SHOWERS AND STORMS
WILL LIKELY QUICKLY FILL IN ACROSS NORTHEAST FLORIDA WITH ACTIVITY
INCREASING ACROSS SOUTHEAST GEORGIA LATER THIS AFTERNOON AS A
SHORTWAVE TROUGH IS FORECAST TO REACH THIS AREA LATE IN THE DAY.
SHOWERS AND STORMS WILL PROVIDE RELIEF FROM THE HEAT AS
TEMPERATURES HAVE ALREADY SOARED INTO THE MID AND UPPER 90S WITH
HEAT INDICES BETWEEN 100 AND 110 DEGREES.

WITH SUCH AN UNSTABLE ATMOSPHERE...SHOWERS AND STORMS WILL LINGER
WELL INTO THE EVENING HOURS. THUS...HAVE INCLUDED CHANCE POPS FOR
MUCH OF THE FORECAST AREA.

STRONG MID/UPPER LEVEL RIDGE THAT HAS BEEN ANCHORED ACROSS THE
AREA THE LAST SEVERAL DAYS IS FORECAST TO TEMPORARILY WEAKEN EARLY
NEXT WEEK...WITH SERIES OF SHORTWAVE TROUGHS DROPPING SOUTHWARD
OVER THE EASTERN SEABOARD AND CARVING A LARGE SCALE TROUGH. ALTHOUGH
TEMPERATURES WILL REMAIN ABOVE NORMAL...READINGS WILL NOT BE
AS OPPRESSIVE WITH FORECAST HIGHS IN THE LOWER TO MID 90S.

STRONGEST DYNAMICS ARE FORECAST TO ARRIVE MONDAY. THIS COUPLED
WITH CONTINUED HIGH ATMOSPHERIC MOISTURE WILL WARRANT LIKELY
POPS ACROSS THE FORECAST AREA.

DRIER AIR WILL BEGIN TO WORK INTO THE AREA FROM THE NORTH ON
TUESDAY AS LONG-WAVE TROUGH EXITS OFFSHORE AND HIGH PRESSURE RIDGE
SLOWLY RETURNS. HAVE INCLUDED CHANCE POPS ACROSS NORTHEAST
DECREASING TO SLIGHT CHANCE POPS ACROSS SOUTHEAST GEORGIA.

HOT READINGS WILL RETURN WEDNESDAY WITH UPPER 90S COMMON ACROSS
THE INTERIOR. HAVE MAINTAINED LIMITED RAIN CHANCES WITH HIGHEST
/30 PERCENT POPS/ RESERVED FOR INTERIOR NORTHEAST FLORIDA.

.LONG TERM...HOT TEMPERATURES WITH LIMITED RAIN CHANCES ARE
FORECAST THURSDAY. RAIN CHANCES WILL INCREASE FRIDAY AND INTO NEXT
WEEKEND AS HIGH PRESSURE RIDGE ONCE AGAIN WEAKENS ACROSS THE
FORECAST AREA.

LOW PRESSURE SYSTEM WELL EAST OF THE WINDWARD ISLANDS IS FORECAST
TO STRENGTHEN INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS
IT TRACKS TOWARDS THE WEST-NORTHWEST. THERE IS MUCH UNCERTAINTY
WITH THIS FEATURE AND INTERESTS ARE URGED TO CLOSELY MONITOR THE
LATEST FORECAST.

&&

.AVIATION...HAVE TSRA IN ALL TAFS TIL AROUND 00Z AS SCATTERED
THUNDERSTORMS CONTINUE TO DEVELOP THIS AFTERNOON. PATCHY FOG
POSSIBLE LATE TONIGHT/EARLY MONDAY WITH MVFR VSBYS MAINLY AT GNV AND
VQQ.

&&

.MARINE...SW WINDS WILL INCREASE DUE TO NIGHTLY SURGE AGAIN TONIGHT
APPROACHING SCEC. NO HEADLINES FOR NOW. WINDS WILL CONTINUE TO
BECOME S TO SE DUE TO AFTERNOON SEABREEZES. SEAS WILL REMAIN IN 2 TO
4 FOOT RANGE.

RIP CURRENTS: LOW RISK WILL CONTINUE THROUGH MONDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  76  96  75  97 /  40  60  30  20
SSI  80  91  79  91 /  30  50  40  20
JAX  77  93  75  94 /  30  60  30  30
SGJ  78  91  77  92 /  20  60  30  30
GNV  76  92  75  93 /  40  60  20  40
OCF  75  93  75  93 /  30  50  20  50

&&

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

ZAPPE/ZIBURA/KEEGAN
Hazardous weather outlook, Jul 31, 5:38 AM EDT, 10 hours 15 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSONVILLE FL
538 AM EDT SUN JUL 31 2011

FLZ020>025-030>033-035>038-040-GAZ132>136-149>154-162>166-010945-
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-
538 AM EDT SUN JUL 31 2011

...HEAT INDICES 105 TO 110 TODAY...

...A FEW STORMS MAY BECOME STRONG TODAY AND TOMORROW....

THIS OUTLOOK IS FOR NORTHEAST FLORIDA AND SOUTHEAST GEORGIA.

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

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EARLY
EVENING...PARTICULARLY BETWEEN I-75 AND I-95. ISOLATED STRONG WIND
GUSTS WILL BE POSSIBLE WITH THESE STORMS.

HIGHS IN THE MID TO UPPER 90S WILL RESULT IN HEAT INDICES BETWEEN
105 AND 110 DEGREES TODAY.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

THUNDERSTORMS WILL BECOME NUMEROUS ON MONDAY. A FEW OF THESE
STORMS COULD PRODUCE DAMAGING WIND GUSTS.

THUNDERSTORM CHANCES WILL BE LOWER THAN NORMAL TUESDAY THROUGH
SATURDAY.

.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.

JDS

In the hours before

Special weather statement, Jul 31, 2:45 PM EDT, 1 hour 8 minutes before
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Special weather statement, Jul 31, 3:37 PM EDT, 16 minutes before
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Special weather statement, Jul 31, 3:39 PM EDT, 14 minutes before
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Special weather statement, Jul 31, 3:40 PM EDT, 13 minutes before
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Special weather statement, Jul 31, 3:49 PM EDT, 4 minutes before
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Special weather statement, Jul 31, 3:50 PM EDT, 3 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
350 PM EDT SUN JUL 31 2011

FLZ040-312030-
MARION-
350 PM EDT SUN JUL 31 2011

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR SOUTHERN MARION
COUNTY FOR STRONG WINDS AND EXCESSIVE LIGHTNING VALID UNTIL 430 PM
EDT...

AT 350 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG
THUNDERSTORMS CENTERED 5 MILES SOUTH OF OCALA AIRPORT...OR 8 MILES
SOUTHWEST OF OCALA...STATIONARY. THESE STRONG THUNDERSTORMS WILL ALSO
AFFECT AREAS AROUND SUMMERFIELD...SILVER SPRINGS SHORES...SANTOS...
OCALA AIRPORT AND BELLEVIEW THROUGH 430 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 2896 8232 2897 8232 2901 8240 2921 8229
      2914 8197 2895 8203
TIME...MOT...LOC 1950Z 033DEG 2KT 2910 8222

STRUBLE

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 10:39 PM EDTSpecial Weather StatementJAXMarion51 min
Jul 31, 2:06 PM EDTSpecial Weather StatementJAXGilchrist24 min
Jul 31, 2:13 PM EDTSpecial Weather StatementJAXSaint Johns32 min
Jul 31, 2:14 PM EDTSpecial Weather StatementJAXDuval31 min
Jul 31, 2:25 PM EDTSpecial Weather StatementJAXMarion35 min
Jul 31, 2:45 PM EDTSpecial Weather StatementJAXDuval45 min
Jul 31, 3:37 PM EDTSpecial Weather StatementJAXSaint Johns38 min
Jul 31, 3:39 PM EDTSpecial Weather StatementJAXCitrus51 min
Jul 31, 3:40 PM EDTSpecial Weather StatementJAXSaint Johns35 min
Jul 31, 3:49 PM EDTSpecial Weather StatementJAXBaker26 min
Jul 31, 3:50 PM EDTSpecial Weather StatementJAXMarion40 min
Jul 31, 4:09 PM EDTSpecial Weather StatementJAXClay36 min
Jul 31, 4:10 PM EDTAreal Flood AdvisoryJAXMarion2 hr
Jul 31, 4:29 PM EDTAreal Flood WarningJAXMarion90 min
Jul 31, 4:36 PM EDTSpecial Weather StatementJAXPutnam39 min
Jul 31, 4:42 PM EDTSpecial Weather StatementJAXNassau33 min
Jul 31, 4:52 PM EDTSevere Thunderstorm WarningJAXColumbia23 min
Jul 31, 5:10 PM EDTSpecial Weather StatementJAXNassau50 min
Jul 31, 5:21 PM EDTSevere Thunderstorm WarningJAXColumbia24 min
Jul 31, 6:20 PM EDTSpecial Weather StatementJAXColumbia40 min
Jul 31, 3:58 PM EDTSpecial Weather StatementJAXCamden47 min
Jul 31, 6:41 PM EDTSpecial Weather StatementJAXBrantley64 min

Nearby

Severe Thunderstorm Warnings in Florida, 2011Every severe thunderstorm warning in 2011

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.