Alert archive / Florida / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 20, NWS Melbourne, FL

April 4, 2017Orange County, Seminole County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Apr 4, 2017, 2:11 PM EDT for Orange County, Seminole County, Florida. It was in force for 49 min. 6 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: Apr 4, 2017, 2:11 PM EDT (18:11 UTC)
Expired: Apr 4, 2017, 3:00 PM EDT
In force: 49 min
Issued by: NWS Melbourne, FL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Orange County, FL, Seminole County, FL

The radar

The Melbourne radar (KMLB), 109 km from the middle of the area, began a volume at 18:12 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
Apr 4, 2:13 PM EDT	HAIL 1	2 Nnw Altamonte Springs, FL	QUARTER SIZE HAIL NEAR INTERSECION OF SR434 AND WEKIVA SPRINGS ROAD.
Apr 4, 2:15 PM EDT	HAIL 1	2 Wnw Altamonte Springs, FL	HAILED FOR ABOUT 4 MINUTES NEAR INTERSECTION OF SAND LAKE AND HUNT CLUB ROADS.
Apr 4, 2:23 PM EDT	HAIL 0.75	Wnw Altamonte Springs, FL	DIME TO PENNY SIZE HAIL NEAR INTERSECTION OF 436 AND MONTGOMERY ROAD.
Apr 4, 2:41 PM EDT	HAIL 0.7	2 E Casselberry, FL	DIME SIZE HAIL NEAR INTERSECTION OF EAGLE CIRCLE AND DODD ROAD IN WINTER SPRINGS.
Apr 4, 2:53 PM EDT	HAIL 1	5 E Casselberry, FL	TRAINED SPOTTER MEASURED ONE INCH HAIL IN WINTER SPRINGS.
Apr 4, 2:55 PM EDT	HAIL 1	5 Ene Casselberry, FL	HAM RADIO OPERATOR MEASURED QUARTER-SIZED HAIL ABOUT 0.75 MILES WEST OF THE INTERSECTION OF SR-417 AND SR-434 IN WINTER SPRINGS

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 4 storm reports to this severe thunderstorm warning; the first came 2 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 6.2 hours before the alert went out and 105 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: 1001 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 699 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 148 m²/s²
0-3 km storm-relative helicity: 183 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 5.4

Open this sounding in Storm Lab

The text

As transmitted.

892 
WUUS52 KMLB 041811
SVRMLB
FLC095-117-041915-
/O.NEW.KMLB.SV.W.0020.170404T1811Z-170404T1915Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Melbourne FL
211 PM EDT TUE APR 4 2017

The National Weather Service in Melbourne has issued a

* Severe Thunderstorm Warning for...
  Western Seminole County in east central Florida... North  
  Orange County in east central Florida...

* Until 315 PM EDT

* At 210 PM EDT, a severe thunderstorm was located over Wekiwa
  Springs State Park, or near Apopka, moving east at 15 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Locations impacted include...
  Orlando, Sanford, Apopka, Altamonte Springs and Ocoee. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 2878 8166 2879 8165 2879 8155 2878 8122
      2858 8120 2858 8165 2859 8165 2859 8166
TIME...MOT...LOC 1810Z 282DEG 11KT 2872 8145 

HAIL...1.00IN
WIND...60MPH
 
$$

Sedlock

2 follow-up statements

480 
WWUS52 KMLB 041834
SVSMLB

Severe Weather Statement
National Weather Service Melbourne FL
234 PM EDT TUE APR 4 2017

FLC095-117-041915-
/O.CON.KMLB.SV.W.0020.000000T0000Z-170404T1915Z/
Seminole FL-Orange FL-
234 PM EDT TUE APR 4 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 315 PM EDT
FOR WESTERN SEMINOLE AND NORTH ORANGE COUNTIES...

At 232 PM EDT, a severe thunderstorm was located over Longwood and 
Lake Mary, moving east at 15 mph. Other cities receiving heavy storm 
activity include Altamonte Springs, Forest City, Fern Park, and 
Casselberry.

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

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

Locations impacted include...
Orlando, Sanford, Apopka, Altamonte Springs, Winter Springs, and 
Ocoee. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of 
a building. Frequent cloud to ground lightning is also occurring 
with this storm cluster.

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

&&

LAT...LON 2875 8166 2879 8165 2879 8155 2878 8122
      2858 8120 2858 8165 2859 8165 2859 8166
TIME...MOT...LOC 1832Z 267DEG 19KT 2872 8132 

HAIL...1.00IN
WIND...60MPH
 
$$

Sedlock

877 
WWUS52 KMLB 041900
SVSMLB

Severe Weather Statement
National Weather Service Melbourne FL
300 PM EDT TUE APR 4 2017

FLC095-117-041908-
/O.CAN.KMLB.SV.W.0020.000000T0000Z-170404T1915Z/
Seminole FL-Orange FL-
300 PM EDT TUE APR 4 2017

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN SEMINOLE AND 
NORTHWESTERN ORANGE COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

The severe thunderstorm warning remains in effect for east central 
Orange, eastern Seminole, southeast Volusia, and north Brevard 
counties until 345 pm.

LAT...LON 2875 8166 2879 8165 2879 8155 2878 8122
      2858 8120 2858 8165 2859 8165 2859 8166
TIME...MOT...LOC 1856Z 282DEG 11KT 2870 8123 

$$

Sedlock

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 Melbourne, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 4, 10:00 AM EDT, 4 hours 11 minutes earlier.

Area forecast discussion, Apr 4, 10:00 AM EDT, 4 hours 11 minutes before

Area Forecast Discussion
National Weather Service Melbourne FL
10 AM EDT Tue Apr 4 2017

.DISCUSSION...

Strong divergence aloft is supporting a band of strong storms across
north FL shifting south toward greater instability over north
Lake/Volusia counties. The divergence is forecast to weaken
considerably by afternoon so the threat for strong/isolated severe
storms will be over Lake and Volusia counties through noon to 1 pm.
Updated the forecast to increase PoPs for Lake and Volusia and lower
max temps based on clouds and precip.

&&

.AVIATION...Primary concern is band of storms slipping south toward
LEE/DAB/SFB with potential for gusty downburst winds and frequent
lightning through 16-17Z.

&&

.MARINE...
Today...small craft exercise caution over much of the waters today
as south winds up to 15-20 knots will persist with seas 4-6 feet.

&

.CLIMATE...
Daytona Beach, Orlando and Melbourne broke their record warm minimum
temperature yesterday, April 3rd. Additional high and warm low
temperature records may be set or tied today and Wednesday.

Current High and Warm Low Temperature Records for the 4th and 5th:

LOC  DATE   HI-MAX   HI-MIN
DAB 4-Apr  93 1974  70 1991
MCO 4-Apr  93 1918  69 1974
MLB 4-Apr  92 1977  71 1974
VRB 4-Apr  92 2012  73 1960

DAB 5-Apr  90 1957  70 1954
MCO 5-Apr  91 1999  68 1957
MLB 5-Apr  91 1977  72 1957
VRB 5-Apr  90 1977  73 1957

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  89  69  90  68 /  30  10  10  50
MCO  92  69  92  69 /  20  10  10  40
MLB  92  71  90  71 /  10  10  10  30
VRB  90  71  89  70 /  10  10  10  30
LEE  88  70  92  68 /  30  10  10  50
SFB  92  70  93  68 /  30  10  10  40
ORL  92  71  92  70 /  20  10  10  40
FPR  90  70  89  69 /  10  10  10  20

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.

&&

Kelly/Sedlock

Hazardous weather outlook, Apr 4, 4:39 AM EDT, 9 hours 32 minutes before

Hazardous Weather Outlook
National Weather Service Melbourne FL
439 AM EDT Tue Apr 4 2017

AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141-
144-147-042045-
Flagler Beach to Volusia-Brevard County Line 0-20 nm-Volusia-
Brevard County Line to Sebastian Inlet 0-20 nm-
Sebastian Inlet to Jupiter Inlet 0-20 nm-Flagler Beach to Volusia-
Brevard County Line 20-60 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm-
Sebastian Inlet to Jupiter Inlet 20-60 nm-Inland Volusia County-
Northern Lake County-Orange-Seminole-Southern Brevard County-
Osceola-Indian River-Okeechobee-St. Lucie-Martin-
Coastal Volusia County-Southern Lake County-
Northern Brevard County-
439 AM EDT Tue Apr 4 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

.THUNDERSTORM IMPACT...
Deeper moisture ahead of a stalled front north of the area, may
generate isolated to scattered showers and lightning storms across
north central Florida, mainly from late this morning into the
afternoon. While main threats will be dangerous cloud to ground
lightning and heavy downpours, isolated stronger storms could
develop and produce strong wind gusts up to 40 to 50 mph and small
hail. Storms will move toward the east-northeast up to 30 to 35
mph.

.RIP CURRENT IMPACT...
A moderate risk for rip currents will continue at the beaches of
east central Florida today. Always swim within sight of a
lifeguard and never swim alone.

.MARINE THUNDERSTORM GUST IMPACT...
Isolated thunderstorms that develop over north central Florida
this afternoon will move toward the east to northeast up to 25 to
30 knots. Any stronger storms will have the potential to produce
wind gusts around 34 knots or greater as they move offshore, north
of Melbourne.

.WIND AND SEA IMPACT...
Southerly winds up to 15 to 20 knots will continue across much of
the adjacent Atlantic waters today. Small craft should exercise
caution.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.
Isolated lightning storms will again be possible ahead of a
stronger cold front late Wednesday night into Thursday.

Poor to hazardous boating conditions will continue across the
coastal waters from mid to late week with the next frontal
passage.

.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be needed today.

Weitlich

In the hours before

Special weather statement, Apr 4, 10:54 AM EDT, 3 hours 17 minutes before

Special Weather Statement
National Weather Service Melbourne FL
1054 AM EDT TUE APR 4 2017

FLZ041-141-041530-
Inland Volusia County FL-Coastal Volusia County FL-
1054 AM EDT TUE APR 4 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL VOLUSIA COUNTY UNTIL 1130
AM EDT...

At 1053 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Ormond Beach to near Port Orange to Deltona.
Movement was east at 40 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Deltona, Daytona Beach, Port Orange, Ormond Beach and DeLand.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 2910 8090 2900 8083 2894 8130 2926 8127
      2927 8115 2932 8115 2936 8103
TIME...MOT...LOC 1453Z 260DEG 38KT 2927 8105 2908 8102 2892 8119

Sedlock

Local storm report, Apr 4, 11:01 AM EDT, 3 hours 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MELBOURNE FL
1101 AM EDT TUE APR 04 2017

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

1048 AM     MARINE TSTM WIND 5 N EDGEWATER           29.05N 80.90W
04/04/2017  M40.00 MPH       VOLUSIA            FL   OTHER FEDERAL

            WEATHERFLOW SITE AT NEW SMYRNA BEACH MEASURED A PEAK WIND
            GUST OF 35 KNOTS FROM THE NORTHEAST WITH A THUNDERSTORM
            JUST TO THE NORTHEAST.

&&

KR

Special weather statement, Apr 4, 12:34 PM EDT, 1 hour 37 minutes before

Special Weather Statement
National Weather Service Melbourne FL
1234 PM EDT TUE APR 4 2017

FLZ041-044-144-041730-
Northern Lake County FL-Inland Volusia County FL-
Southern Lake County FL-
1234 PM EDT TUE APR 4 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL and Northern LAKE
County AND NORTHWESTERN VOLUSIA COUNTy UNTIL 130 PM EDT...

At 1233 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Salt Springs to 8 miles northwest of
Mascotte. Movement was east-southeast at 25 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
DeLand, Leesburg, Eustis, Tavares and Lady Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near a lake, get out of the water and move indoors or
inside a vehicle. If you can hear thunder, you are close enough to
be struck by lightning. Move to safe shelter now! Do not be caught
on the water in a thunderstorm.

&&

LAT...LON 2888 8195 2896 8193 2896 8166 2905 8166
      2906 8164 2928 8164 2932 8168 2938 8145
      2940 8142 2926 8142 2926 8133 2900 8122
      2885 8135 2886 8135 2888 8136 2883 8142
      2879 8142 2879 8165 2874 8166 2868 8195
TIME...MOT...LOC 1633Z 290DEG 20KT 2929 8170 2869 8196

Sedlock

Local storm report, Apr 4, 12:42 PM EDT, 1 hour 29 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MELBOURNE FL
1242 PM EDT TUE APR 04 2017

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

1200 PM     MARINE TSTM WIND 1 S PLAYALINDA BEACH    28.63N 80.62W
04/04/2017  M40.00 MPH       BREVARD            FL   MESONET

            USAF TOWER 0397 MEASURED A PEAK WIND GUST OF 35 KTS OUT
            OF THE NORTHEAST.

1200 PM     MARINE TSTM WIND 4 NNE HAULOVER CANAL    28.80N 80.74W
04/04/2017  M44.00 MPH       VOLUSIA            FL   MESONET

            USAF TOWER 0022 MEASURED A PEAK WIND GUST OF 38 KTS FROM
            THE NORTHEAST

&&

KR

Local storm report, Apr 4, 1:35 PM EDT, 36 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MELBOURNE FL
135 PM EDT TUE APR 04 2017

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

0113 PM     TSTM WND GST     LEESBURG AIRPORT        28.82N 81.81W
04/04/2017  M39.00 MPH       LAKE               FL   ASOS

&&

PG

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 4, 10:07 AM EDT	Special Marine Warning	MLB		3 hr
Apr 4, 10:54 AM EDT	Special Weather Statement	MLB	Volusia	36 min
Apr 4, 12:07 PM EDT	Special Marine Warning	MLB		53 min
Apr 4, 12:34 PM EDT	Special Weather Statement	MLB	Lake	56 min
Apr 4, 1:12 PM EDT	Severe Thunderstorm Warning	MLB	Lake, Orange	63 min
Apr 4, 2:49 PM EDT	Severe Thunderstorm Warning	MLB	Brevard, Orange, Seminole, Volusia	56 min
Apr 4, 3:04 PM EDT	Special Marine Warning	MLB		116 min
Apr 4, 3:06 PM EDT	Special Weather Statement	MLB	Brevard	24 min
Apr 4, 3:13 PM EDT	Special Weather Statement	MLB	Okeechobee, Osceola	62 min
Apr 4, 3:37 PM EDT	Special Weather Statement	MLB	Brevard	23 min
Apr 4, 3:41 PM EDT	Special Marine Warning	MLB		64 min
Apr 4, 3:41 PM EDT	Severe Thunderstorm Warning	MLB	Brevard	49 min
Apr 4, 4:07 PM EDT	Severe Thunderstorm Warning	MLB	Indian River, Okeechobee, Osceola	38 min
Apr 4, 4:08 PM EDT	Severe Thunderstorm Warning	MLB	Osceola	67 min
Apr 4, 4:12 PM EDT	Special Weather Statement	MLB	Indian River	48 min
Apr 4, 4:24 PM EDT	Special Weather Statement	MLB	Indian River	66 min
Apr 4, 4:42 PM EDT	Severe Thunderstorm Warning	MLB	Indian River	35 min
Apr 4, 4:44 PM EDT	Special Marine Warning	MLB		91 min
Apr 4, 6:01 PM EDT	Special Weather Statement	MLB	Okeechobee	59 min

Nearby

Severe Thunderstorm Warnings in Florida, 2017 Every severe thunderstorm warning in 2017

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.