Alert archive / Mississippi / Tornado Watches in 2015

Tornado Watch 522

October 26, 2015Saint Bernard Parish, Louisiana; Hancock County, Harrison County, Jackson County, Mississippi

The Storm Prediction Center issued this tornado watch at Oct 26, 2015, 2:05 AM CDT for Saint Bernard Parish, Louisiana; Hancock County, Harrison County, Jackson County, Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Oct 26, 2015, 2:05 AM CDT (07:05 UTC)
Expired: Oct 26, 2015, 9:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

Counties Saint Bernard Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS

The radar

The Mobile radar (KMOB), 107 km from the middle of the area, began a volume at 07:05 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 SPC expected

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

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 10%
One or more gusts of 65 knots or more: 5%
Ten or more severe hail reports: 5%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 30%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Oct 26, 3:26 AM CDT	Flash Flood Warning	LIX	Hancock	4 hr

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 00:00Z, 7.1 hours before the alert went out and 59 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: 318 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 488 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 468 m²/s²
0-3 km storm-relative helicity: 554 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 3.6

Open this sounding in Storm Lab

The text

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

730 
WWUS20 KWNS 260700
SEL2  
SPC WW 260700
LAZ000-MSZ000-CWZ000-261400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 522
NWS STORM PREDICTION CENTER NORMAN OK
205 AM CDT MON OCT 26 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  EXTREME SOUTHEAST LOUISIANA
  THE MISSISSIPPI COAST
  COASTAL WATERS

* EFFECTIVE THIS MONDAY MORNING FROM 205 AM UNTIL 900 AM CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE

SUMMARY...SMALL ROTATING THUNDERSTORMS WILL CONTINUE TO FORM AND
MOVE NWD FROM THE MS SOUND INTO THE COASTAL MS COUNTIES THROUGH THE
EARLY MORNING HOURS...WITH AN ATTENDANT RISK FOR A TORNADO OR TWO.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 35 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 50 MILES SOUTHWEST OF
GULFPORT MISSISSIPPI TO 50 MILES EAST SOUTHEAST OF GULFPORT
MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

&&

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 521. WATCH NUMBER 521 WILL NOT BE IN EFFECT AFTER
205 AM CDT. 

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 18035.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 25, 7:12 PM CDT	Tornado Watch	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 3 more	7 hr
Oct 25, 10:15 PM CDT	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 4 more	2 hr
Oct 26, 1:32 AM CDT	Mesoscale Discussion	SPC	Saint Bernard	118 min
Oct 25, 7:53 PM CDT	Mesoscale Discussion	SPC	George, Jackson	3 hr
Oct 26, 7:32 AM CDT	Mesoscale Discussion	SPC	George, Jackson	118 min

Nearby

Tornado Watches in Mississippi, 2015 Tornado Watches in Louisiana, 2015 Every tornado 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; radar from the NEXRAD Level II archive.