Alert archive / Florida / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 136, NWS Tallahassee, FL

July 21, 20186 counties in Florida

NWS Tallahassee, FL issued this severe thunderstorm warning at Jul 21, 2018, 1:40 PM EDT for 6 counties in Florida. It was in force for 65 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 21, 2018, 1:40 PM EDT (17:40 UTC)
Expired: Jul 21, 2018, 2:45 PM EDT
In force: 65 min
Issued by: NWS Tallahassee, FL
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Gadsden County, FL, Jefferson County, FL, Leon County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL

The radar

The Tallahassee radar (KTLH), 28 km from the middle of the area, began a volume at 17:42 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 21, 11:12 AM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 5.7 hours before the alert went out and 25 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: 1280 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 852 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 94 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 Tallahassee, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 9:49 AM EDT, 3 hours 51 minutes earlier.

Area forecast discussion, Jul 21, 9:49 AM EDT, 3 hours 51 minutes before

Area Forecast Discussion
National Weather Service Tallahassee FL
949 AM EDT Sat Jul 21 2018

.NEAR TERM [Through Today]...

Two MCSs, one to our north in GA and one to our northwest in AL
are steadily moving south-southwest toward our area at a fast
forward speed of around 35-40 kts. The GA MCS is poised to reach
our northern line of counties in about an hour. The environment
over our area as these storms approach is extremely unstable, with
80 degree dewpoints seen as far north as Enterprise, AL this
morning and SPC mesoanalysis showing 6000 J/kg SBCAPE along the FL
Panhandle. The 12Z sounding from BMX this morning sampled some of
the shear that will be moving in with these MCSs and showed 27 kts
0-1km shear and 39 kts 0-6 km shear. It is highly unusual for
this time of year to have such high shear this far south and when
coupled with the extreme instability there is potential for severe
weather. SPC has highlighted the majority of our area in a slight
risk for today. The main threats will be damaging straight-line
winds and large hail, but an isolated tornado cannot be ruled out.

&&

.PREV DISCUSSION [535 AM EDT]...

.SHORT TERM [Tonight Through Monday]...

In the upper levels a trough centered over the Midwest will deepen
into the Southeast this weekend. At the surface a low over the Ohio
River Valley will drift southward over the weekend bringing another
cold front into the region tonight and into Sunday. A weak low or
boundary will remain over the region on Monday. With abundant
moisture (PW values around 2 inches)POPs will be high through
Monday.

Severe storms are possible Saturday night through Sunday night with
the main threat being damaging straight-line winds. A MCS is
possible tonight as deep layer shear increases to 35 to 45 knots
this evening. Conditions will also be favorable for severe on Sunday
and Sunday night with deep layer shear around 35 to 45 knots and
CAPE at 4000 to 5000 J/KG. SPC has a marginal risk over the region
on Saturday night with a slight risk over SE Alabama and SW Georgia.
SPC has a marginal risk for the region on Sunday with a slight risk
for parts of the Florida Big Bend and South Central Georgia.

Highs will be in the low to mid 90s on Sunday and near 90 on Monday.
Lows will be in the low to mid 70s.

.LONG TERM [Monday Night Through Saturday]...

In the upper levels a trough will be over the Southeast. At the
surface a weak low will remain over the Southeast through Tuesday.
The rest of the week southerly flow will dominate with high pressure
to the east over the Atlantic. The wet pattern will continue next
week and POPs will be high (50 to 70 percent through Thursday).
Highs will be in the low 90s or near 90. Lows will be in the low to
mid 70s.

.AVIATION...

[Through 12z Sunday] Some patchy fog and low ceilings are possible
early this morning, particularly around VLD, with VFR conditions
returning a couple of hours after sunrise. However, scattered
thunderstorms are expected during the day into the evening with some
storms possibly becoming severe. Outside of storms and the brief
early morning fog or low ceilings, VFR conditions are expected.

.MARINE...

Moderate westerly winds will increase tonight and even more on
Sunday morning. Winds will be 15 to 20 knots on Saturday night and
20 to 25 knots on Sunday. A Small Craft Advisory is likely for
Sunday as winds are expected to exceed 20 knots.

.FIRE WEATHER...

Red flag conditions will not occur over the next several with
moisture expected to remain high across the area.

.HYDROLOGY...

The wet pattern continues through this weekend and next week. 1 to
1.5 inches of rain is predicted through Monday night. Locally higher
amounts are likely. The heavier downpours may result in ponding of
water on roadways and flooding of low-lying areas. Most local rivers
are steady or slowly rising at this time. Most local rivers remain
below action stage.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is requested. Spotters should safely report
significant weather conditions and/or damage by calling the office or
tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   94  76  93  73  91 /  50  30  60  50  60
Panama City   91  79  90  77  91 /  40  20  40  40  40
Dothan        93  75  93  73  90 /  70  40  50  30  50
Albany        93  75  92  73  90 /  70  50  50  30  60
Valdosta      93  74  92  73  91 /  50  40  60  30  60
Cross City    91  76  90  74  90 /  30  30  60  50  50
Apalachicola  90  80  90  77  90 /  40  10  40  50  40

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&

NEAR TERM...Nguyen
SHORT TERM...McD
LONG TERM...McD
AVIATION...DVD
MARINE...McD
FIRE WEATHER...DVD
HYDROLOGY...McD

In the hours before

Local storm report, Jul 21, 12:05 PM EDT, 1 hour 35 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1205 PM EDT SAT JUL 21 2018

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

1135 AM     TSTM WND DMG     1 WSW COLUMBIA          31.29N 85.13W
07/21/2018                   HOUSTON            AL   911 CALL CENTER

            TREE DOWN.

&&

PC

Local storm report, Jul 21, 12:15 PM EDT, 1 hour 25 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1215 PM EDT SAT JUL 21 2018

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

1135 AM     TSTM WND DMG     2 S BLAKELY             31.36N 84.94W
07/21/2018                   EARLY              GA   911 CALL CENTER

            TREES DOWN ACROSS THE COUNTY.

&&

PC

Local storm report, Jul 21, 12:18 PM EDT, 1 hour 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1218 PM EDT SAT JUL 21 2018

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

1130 AM     TSTM WND DMG     5 SW DOLES              31.66N 83.95W
07/21/2018                   WORTH              GA   BROADCAST MEDIA

            MEDIA REPORT OF TREES DOWN ON CAMP OSBORN
            ROAD.

&&

PC

Local storm report, Jul 21, 1:10 PM EDT, 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
110 PM EDT SAT JUL 21 2018

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

1255 PM     TSTM WND GST     THOMASVILLE             30.91N 83.88W
07/21/2018  M56 MPH          THOMAS             GA   AWOS

            AWOS STATION TVI, THOMASVILLE.

&&

PC

Local storm report, Jul 21, 1:31 PM EDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
131 PM EDT SAT JUL 21 2018

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

1142 AM     TSTM WND DMG     ARLINGTON               31.44N 84.73W
07/21/2018                   CALHOUN            GA   PUBLIC

            REPORTS OF TREES DOWN ON HOMES AND NUMEROUS
            POWER LINES DOWN.

&&

RH

Local storm report, Jul 21, 1:36 PM EDT, 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
136 PM EDT SAT JUL 21 2018

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

1206 PM     TSTM WND DMG     1 N COLQUITT            31.18N 84.74W
07/21/2018                   MILLER             GA   911 CALL CENTER

            NUMEROUS TREES AND POWER LINES REPORTED DOWN
            ACROSS MILLER COUNTY.

&&

RH

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 12:10 PM EDT	Severe Thunderstorm Warning	TAE	Gadsden	50 min
Jul 21, 12:48 PM EDT	Severe Thunderstorm Warning	TAE	Calhoun, Gadsden, Gulf, Leon, Liberty, Wakulla	42 min
Jul 21, 12:54 PM EDT	Severe Thunderstorm Warning	TAE	Gadsden, Jefferson, Leon, Madison, Wakulla	51 min
Jul 21, 1:02 PM EDT	Tornado Warning	TAE	Gadsden, Leon	28 min
Jul 21, 1:14 PM EDT	Special Marine Warning	TAE		91 min
Jul 21, 1:43 PM EDT	Special Marine Warning	TAE		62 min
Jul 21, 2:12 PM EDT	Severe Thunderstorm Warning	TAE	Franklin, Gulf	33 min
Jul 21, 2:35 PM EDT	Special Marine Warning	TAE		115 min
Jul 21, 2:39 PM EDT	Severe Thunderstorm Warning	TAE	Dixie, Lafayette, Taylor	66 min
Jul 21, 3:43 PM EDT	Special Weather Statement	TAE	Dixie	47 min
Jul 21, 4:13 PM EDT	Small Craft Advisory	TAE		36 hr
Jul 21, 10:27 AM EDT	Special Weather Statement	TAE	Calhoun, Dougherty, Randolph, Terrell	63 min
Jul 21, 10:34 AM EDT	Special Weather Statement	TAE	Ben Hill, Irwin	41 min
Jul 21, 10:46 AM EDT	Special Weather Statement	TAE	Lee, Turner, Worth	44 min
Jul 21, 10:55 AM EDT	Severe Thunderstorm Warning	TAE	Baker, Dougherty, Lee, Mitchell, Terrell, Worth	65 min
Jul 21, 11:12 AM EDT	Severe Thunderstorm Warning	TAE	Baker, Calhoun, Dougherty, Lee, Randolph, Terrell	48 min
Jul 21, 11:25 AM EDT	Severe Thunderstorm Warning	TAE	Baker, Calhoun, Clay, Decatur, Dougherty, Early and 4 more	50 min
Jul 21, 11:56 AM EDT	Severe Thunderstorm Warning	TAE	Baker, Calhoun, Colquitt, Dougherty, Grady, Mitchell and 1 more	64 min

Nearby

Severe Thunderstorm Warnings in Florida, 2018 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.