Alert archive / Alabama / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 113

April 25, 201511 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida

The Storm Prediction Center issued this severe thunderstorm watch at Apr 25, 2015, 1:36 PM CDT for 11 counties in Alabama; Escambia County, Okaloosa County, Santa Rosa County, Florida. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 25, 2015, 1:36 PM CDT (18:36 UTC)
Expired
Apr 25, 2015, 5:15 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Baldwin County, AL, Butler County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Escambia County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 25, 2:21 PM CDTSevere Thunderstorm WarningMOBMobile24 min
Apr 25, 2:47 PM CDTSevere Thunderstorm WarningMOBBaldwin, Mobile43 min
Apr 25, 2:48 PM CDTSevere Thunderstorm WarningMOBBaldwin, Escambia, Monroe27 min
Apr 25, 3:26 PM CDTSevere Thunderstorm WarningMOBBaldwin64 min
Apr 25, 3:48 PM CDTSevere Thunderstorm WarningMOBButler, Conecuh, Covington, Crenshaw, Escambia57 min
Apr 25, 3:57 PM CDTSevere Thunderstorm WarningMOBOkaloosa, Santa Rosa53 min
Apr 25, 4:38 PM CDTSevere Thunderstorm WarningMOBOkaloosa26 min
Apr 25, 4:43 PM CDTSevere Thunderstorm WarningMOBButler, Covington, Crenshaw24 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 6.6 hours before the alert went out and 214 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, Slidell Radar S, LA at 12:00Z on 2015-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1826 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, Slidell Radar S, LA at 12:00Z on 2015-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 square meters per square second.19395878Sfc1 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
1826 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
565 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
1.0
Supercell composite
4.6

Open this sounding in Storm Lab

The text

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

253 
WWUS20 KWNS 251833
SEL3  
SPC WW 251833
ALZ000-FLZ000-CWZ000-260200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 113
NWS STORM PREDICTION CENTER NORMAN OK
135 PM CDT SAT APR 25 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  SOUTHWEST ALABAMA
  WESTERN FLORIDA PANHANDLE
  COASTAL WATERS

* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 135 PM UNTIL
  900 PM CDT.

* PRIMARY THREATS INCLUDE...
  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...SEVERE STORMS ONGOING OVER SOUTHEAST MISSISSIPPI ARE
EXPECTED TO SPREAD EAST ACROSS THE WATCH AREA THIS AFTERNOON INTO
EVENING.  LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS
WITH THESE STORMS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES SOUTH
SOUTHWEST OF PENSACOLA FLORIDA TO 35 MILES NORTH NORTHWEST OF
EVERGREEN ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 110...WW 111...WW 112...

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM
MOTION VECTOR 27035.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 25, 12:50 AM CDTTornado WatchSPCDallas, Fayette, Greene, Hale, Lamar, Marengo and 4 more6 hr
Apr 25, 2:07 AM CDTMesoscale DiscussionSPCChoctaw, Greene, Pickens, Sumter, Tuscaloosa83 min
Apr 25, 4:12 AM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Dallas and 9 more63 min
Apr 25, 5:00 AM CDTTornado WatchSPCAutauga, Baldwin, Barbour, Bullock, Butler, Clarke and 18 more7 hr
Apr 25, 7:41 AM CDTMesoscale DiscussionSPCCoffee, Covington, Dale, Geneva, Henry, Houston94 min
Apr 25, 9:35 AM CDTMesoscale DiscussionSPCBaldwin, Mobile, Washington115 min
Apr 25, 1:50 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 4 more85 min
Apr 25, 2:10 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Calhoun, Chambers, Chilton and 19 more95 min
Apr 25, 3:07 PM CDTSevere Thunderstorm WatchSPCBarbour, Coffee, Dale, Geneva, Henry, Houston and 1 more7 hr
Apr 25, 4:38 PM CDTSevere Thunderstorm WatchSPCBullock, Chambers, Clay, Lee, Macon, Randolph and 2 more5 hr
Apr 25, 8:08 AM CDTTornado WatchSPCBaker, Calhoun, Columbia, Duval, Franklin, Gadsden and 11 more7 hr
Apr 25, 11:20 AM CDTMesoscale DiscussionSPCColumbia, Gadsden, Hamilton, Jefferson, Lafayette, Leon and 5 more85 min
Apr 25, 2:30 PM CDTMesoscale DiscussionSPCBaker, Columbia, Duval, Gadsden, Hamilton, Jefferson and 5 more60 min
Apr 25, 6:19 PM CDTMesoscale DiscussionSPCCalhoun, Franklin, Gadsden, Gulf, Hamilton, Jackson and 6 more56 min

Nearby

Severe Thunderstorm Watches in Alabama, 2015Severe Thunderstorm Watches in Florida, 2015Every severe thunderstorm watch in 2015

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.