Alert archive / New Jersey / Tornado Watches in 2014

Tornado Watch 26

February 21, 201413 counties in New Jersey; 5 counties in Pennsylvania

The Storm Prediction Center issued this tornado watch at Feb 21, 2014, 12:38 PM EST for 13 counties in New Jersey; 5 counties in Pennsylvania. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Feb 21, 2014, 12:38 PM EST (17:38 UTC)
Expired: Feb 21, 2014, 3:29 PM EST
In force: 3 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

Counties Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 52 km from the middle of the area, began a volume at 17:37 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: 50%
One or more gusts of 65 knots or more: 10%
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: 70%

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
Feb 21, 2:09 PM EST	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Cape May, Cumberland, Ocean	66 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

Brookhaven, NY (KOKX), launched 12:00Z, 5.6 hours before the alert went out and 204 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 362 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 227 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

408 
WWUS20 KWNS 211740
SEL6  
SPC WW 211740
NJZ000-PAZ000-CWZ000-212200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 26
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM EST FRI FEB 21 2014

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN AND CENTRAL NEW JERSEY
  SOUTHEAST PENNSYLVANIA
  COASTAL WATERS

* EFFECTIVE THIS FRIDAY AFTERNOON FROM 1240 PM UNTIL 500 PM EST.

* PRIMARY THREATS INCLUDE...
  SEVERAL TORNADOES POSSIBLE
  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHEAST OF TRENTON
NEW JERSEY TO 30 MILES SOUTHEAST OF WILMINGTON DELAWARE.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU6).

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...CONTINUE...WW 22...WW 23...WW 24...WW
25...

DISCUSSION...PRE-FRONTAL TSTMS NOW STRENGTHENING OVER NERN AND SRN
MD EXPECTED TO MOVE/DEVELOP RAPIDLY NNEWD OVER THE NEXT FEW HOURS AS
BOUNDARY LAYER OVER WW AREA CONTINUES TO DESTABILIZE FROM THE SOUTH
IN RESPONSE TO STRONG SSW LOW-LVL FLOW/PRESSURE FALLS AHEAD OF COLD
FRONT NOW DESCENDING THE ERN SLOPES OF THE APPALACHIANS. AREA VWP
DATA SHOW 60 KT SSWLY 1 KM WINDS VEERING TO 75 KT SWLY FLOW AT 500
MB...YIELDING LONG/SLIGHTLY CURVED HODOGRAPHS FAVORABLE FOR
LEWPS/SMALL BOWS THAT COULD YIELD NARROW SWATHS OF DMGG WIND AND
POSSIBLY A COUPLE TORNADOES.

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
350. MEAN STORM MOTION VECTOR 23055.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 21, 10:39 AM EST	Tornado Watch	SPC	Kent, New Castle, Sussex	5 hr
Feb 21, 12:16 PM EST	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	89 min
Feb 21, 2:07 PM EST	Mesoscale Discussion	SPC	Sussex	53 min

Nearby

Tornado Watches in New Jersey, 2014 Tornado Watches in Pennsylvania, 2014 Every tornado watch in 2014

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.