Alert archive / Florida / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 21, NWS Miami, FL

August 9, 2018Palm Beach County, Florida

NWS Miami, FL issued this severe thunderstorm warning at Aug 9, 2018, 8:54 PM EDT for Palm Beach County, Florida. It was in force for 36 min. 4 reports 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
Aug 9, 2018, 8:54 PM EDT (00:54 UTC)
Expired
Aug 9, 2018, 9:30 PM EDT
In force
36 min
Issued by
NWS Miami, FL
Area
Storm-based polygon
Hail
0.88 in
Wind
70.0 mph

County Palm Beach County, FL

The radar

The Melbourne radar (KMLB), 133 km from the middle of the area, began a volume at 00:56 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.

What was reported inside it

TimeReportWhereRemark
Aug 9, 8:55 PM EDTTSTM WND GST 60Port Mayaca, FLA TRAINED SPOTTER ESTIMATED WINDS GUSTING TO 60-65MPH IN PORT MAYACA AS A STORM MOVED ONSHORE FROM LAKE OKEECHOBEE.
Aug 9, 8:56 PM EDTTSTM WND GST 484 Nne Canal Point, FLMESONET SITE C10A S-271 RECORDED A GUST TO 42 KNOTS/48 MPH WITH A THUNDERSTORM.
Aug 9, 8:56 PM EDTTSTM WND DMGSe Port Mayaca, FL...DELAYED REPORT...PUBLIC REPORTS NUMEROUS LARGE TREES DOWN BETWEEN PORT MAYACA TO THE MARTIN/PALM BEACH COUNTY LINE. ANOTHER REPORT VIA SOCIAL MEDIA OF POWERLINES DOWN IN THE SAME AREA ON THE EASTERN SHORE OF LAKE OKEECHOBEE.
Aug 9, 9:03 PM EDTTSTM WND DMG7 Nne Canal Point, FLMEMBER OF PUBLIC, AN EMPLOYEE OF LOCAL BUSINESS, REPORTS NUMEROUS LARGE TREE BRANCHES DOWN, 6-INCHES IN DIAMETER. ALSO, THE TOP OF A PALM TREE WAS SNAPPED OFF. TIME ESTIMATED BASED ON DOPPLER RADAR.

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

The nearest sounding before it

Miami, FL (KMFL), launched 00:00Z, 0.9 hours before the alert went out and 127 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, Miami, FL at 00:00Z on 2018-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 974 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Miami, FL at 00:00Z on 2018-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
974 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1305 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

015 
WUUS52 KMFL 100054
SVRMFL
FLC099-100130-
/O.NEW.KMFL.SV.W.0021.180810T0054Z-180810T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Miami FL
854 PM EDT THU AUG 9 2018

The National Weather Service in Miami has issued a

* Severe Thunderstorm Warning for...
  Northwestern Palm Beach County in southeastern Florida...

* Until 930 PM EDT.

* At 854 PM EDT, a severe thunderstorm was located near Canal Point,
  and is nearly stationary.

  HAZARD...70 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Pahokee, Canal Point and Fremd Village-Padgett Island. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Miami. You can also share your report with NWS Miami on
Facebook and Twitter.

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 2696 8061 2696 8043 2674 8044 2675 8074
      2689 8072 2692 8070 2698 8069 2702 8065
      2702 8063
TIME...MOT...LOC 0054Z 295DEG 1KT 2694 8064 

HAIL...0.88IN
WIND...70MPH
 
$$

67
1 follow-up statement
258 
WWUS52 KMFL 100112
SVSMFL

Severe Weather Statement
National Weather Service Miami FL
912 PM EDT THU AUG 9 2018

FLC099-100130-
/O.CON.KMFL.SV.W.0021.000000T0000Z-180810T0130Z/
Palm Beach FL-
912 PM EDT THU AUG 9 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHWESTERN PALM BEACH COUNTY...

At 912 PM EDT, a severe thunderstorm was located near Canal Point,
and is nearly stationary.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Pahokee, Canal Point and Fremd Village-Padgett Island. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Miami. You can also share your report with NWS Miami on Facebook and
Twitter.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 2696 8061 2696 8043 2674 8044 2675 8074
      2689 8072 2692 8070 2698 8069 2702 8065
      2702 8063
TIME...MOT...LOC 0112Z 295DEG 1KT 2694 8063 

HAIL...0.88IN
WIND...60MPH
 
$$

67

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 8:12 PM EDTSpecial Marine WarningMFL33 min
Aug 9, 8:44 PM EDTSpecial Marine WarningMFL31 min
Aug 9, 8:48 PM EDTSpecial Weather StatementMFLPalm Beach42 min
Aug 9, 9:11 PM EDTSpecial Marine WarningMFL34 min
Aug 9, 9:24 PM EDTSpecial Weather StatementMFLPalm Beach51 min
Aug 9, 9:54 PM EDTSpecial Weather StatementMFLPalm Beach51 min
Aug 10, 3:28 PM EDTSpecial Weather StatementMFLCollier47 min
Aug 10, 3:39 PM EDTSpecial Weather StatementMFLMiami-Dade51 min
Aug 10, 3:46 PM EDTSpecial Weather StatementMFLPalm Beach44 min
Aug 10, 3:56 PM EDTSpecial Marine WarningMFL34 min
Aug 10, 4:05 PM EDTSpecial Weather StatementMFLMartin40 min
Aug 10, 4:26 PM EDTSpecial Weather StatementMFLCollier49 min
Aug 10, 4:33 PM EDTSpecial Marine WarningMFL27 min
Aug 10, 4:41 PM EDTSpecial Weather StatementMFLBroward, Palm Beach79 min
Aug 10, 4:55 PM EDTSpecial Marine WarningMFL95 min
Aug 10, 5:35 PM EDTSevere Thunderstorm WarningMFLMiami-Dade25 min
Aug 10, 5:38 PM EDTSpecial Marine WarningMFL37 min
Aug 10, 5:57 PM EDTSpecial Weather StatementMFLMiami-Dade48 min
Aug 10, 6:15 PM EDTSpecial Marine WarningMFL90 min
Aug 10, 7:55 PM EDTSpecial Marine WarningMFL35 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.