Alert archive / Florida / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 2, NWS Key West, FL

May 30, 2009Monroe County, Florida

NWS Key West, FL issued this severe thunderstorm warning at May 30, 2009, 5:31 PM EDT for Monroe County, Florida. It was in force for 44 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 30, 2009, 5:31 PM EDT (21:31 UTC)
Expired: May 30, 2009, 6:15 PM EDT
In force: 44 min
Issued by: NWS Key West, FL
Area: Storm-based polygon

County Monroe County, FL

The radar

The Key West radar (KBYX), 71 km from the middle of the area, began a volume at 21:32 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.

What was reported inside it

Time	Report	Where	Remark
May 30, 5:41 PM EDT	HAIL 0.25	2 Ne Marathon, FL	A TRAINED SPOTTER REPORTED SMALL HAIL AND FREQUENT LIGHTNING DURING A THUNDERSTORM.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Key West, FL (KEYW), launched 12:00Z, 9.5 hours before the alert went out and 73 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: 2254 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 754 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS52 KKEY 302131
SVRKEY
FLC087-302215-
/O.NEW.KKEY.SV.W.0002.090530T2131Z-090530T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE KEY WEST FL
531 PM EDT SAT MAY 30 2009

THE NATIONAL WEATHER SERVICE IN KEY WEST HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MIDDLE KEYS IN MONROE COUNTY IN FLORIDA...
  THIS INCLUDES THE COMMUNITY OF MARATHON...

* UNTIL 615 PM EDT

* AT 530 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  A SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED JUST NORTH OF 
  MARATHON...AND MOVING EAST AT 15 MPH.

* COMMUNITIES IN THE PATH OF THE SEVERE WEATHER INCLUDE 
MARATHON...KEY COLONY AND DUCK KEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DAMAGING WINDS...DEADLY LIGHTNING...AND VERY HEAVY RAIN ARE LIKELY
WITH THIS STORM. TAKE COVER IN A STURDY BUILDING UNTIL THE STORM
PASSES.

&&

LAT...LON 2472 8112 2474 8103 2478 8094 2477 8092
      2478 8091 2478 8089 2476 8089 2476 8091
      2477 8092 2472 8100 2472 8105 2468 8108
      2468 8111
TIME...MOT...LOC 2130Z 260DEG 14KT 2475 8102

$$

DFM/KBK

2 follow-up statements

000 
WWUS52 KKEY 302205
SVSKEY

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE KEY WEST FL
605 PM EDT SAT MAY 30 2009

FLC087-302215-
/O.CON.KKEY.SV.W.0002.000000T0000Z-090530T2215Z/
MIDDLE KEYS IN MONROE FL-
605 PM EDT SAT MAY 30 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR MIDDLE KEYS IN MONROE COUNTY...

AT 603 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DIME SIZE HAIL. 
THIS STORM WAS LOCATED NEAR THE SEVEN MILE BRIDGE...MARATHON 
AIRPORT...ND BOOT KEY HARBOR...MOVING SLOWLY EAST.

IN ADDITION TO DAMAGING WINDS AND HAIL...CONTINUOUS CLOUD TO GROUND 
LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY 
LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN
HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

LAT...LON 2472 8112 2474 8103 2478 8094 2477 8092
      2478 8091 2478 8089 2476 8089 2476 8091
      2477 8092 2472 8100 2472 8105 2468 8108
      2468 8111
TIME...MOT...LOC 2204Z 260DEG 14KT 2477 8088

$$

DFM

000 
WWUS52 KKEY 302220
SVSKEY

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE KEY WEST FL
620 PM EDT SAT MAY 30 2009

FLC087-302228-
/O.EXP.KKEY.SV.W.0002.000000T0000Z-090530T2215Z/
MIDDLE KEYS IN MONROE FL-
620 PM EDT SAT MAY 30 2009

...THE SEVERE THUNDERSTORM WARNING FOR MIDDLE KEYS IN MONROE COUNTY
HAS EXPIRED...

STORMS IN THE VICINITY OF MARATHON HAVE DECREASED BELOW SEVERE 
LIMITS...BUT CONTINUE IN PLACE WHILE EXHIBITING STRONG SIGNATURES. 

LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS FROM YOUR NATIONAL 
WEATHER SERVICE.

LAT...LON 2472 8112 2474 8103 2478 8094 2477 8092
      2478 8091 2478 8089 2476 8089 2476 8091
      2477 8092 2472 8100 2472 8105 2468 8108
      2468 8111
TIME...MOT...LOC 2205Z 260DEG 14KT 2477 8087

$$

DFM

The office that day

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

Issued	Product	Office	Lasted
May 29, 8:48 PM EDT	Special Marine Warning	KEY	57 min
May 30, 2:50 AM EDT	Special Marine Warning	KEY	26 min
May 30, 12:50 PM EDT	Special Marine Warning	KEY	26 min
May 30, 2:22 PM EDT	Special Marine Warning	KEY	53 min
May 30, 3:05 PM EDT	Special Marine Warning	KEY	25 min
May 30, 3:36 PM EDT	Special Marine Warning	KEY	28 min
May 30, 4:00 PM EDT	Special Marine Warning	KEY	60 min
May 30, 4:58 PM EDT	Special Marine Warning	KEY	62 min

Nearby

Severe Thunderstorm Warnings in Florida, 2009 Every severe thunderstorm warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.