

539 

WWUS20 KWNS 131813

SEL8

SPC WW 131813

MDZ000-NCZ000-VAZ000-CWZ000-140200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 308

NWS STORM PREDICTION CENTER NORMAN OK

210 PM EDT THU JUN 13 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHERN MARYLAND

  EASTERN NORTH CAROLINA

  SOUTHEAST VIRGINIA

  COASTAL WATERS



* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 210 PM UNTIL

  1000 PM EDT.



...THIS IS A PARTICULARLY DANGEROUS SITUATION...



* PRIMARY THREATS INCLUDE...

  NUMEROUS SIGNIFICANT DAMAGING WIND GUSTS TO 80 MPH LIKELY

  SEVERAL VERY LARGE HAIL EVENTS TO 3 INCHES IN DIAMETER POSSIBLE

  A FEW TORNADOES POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90

STATUTE MILES EITHER SIDE OF A LINE FROM 20 MILES NORTH NORTHWEST

OF NORFOLK VIRGINIA TO 35 MILES SOUTH SOUTHWEST OF SOUTHERN PINES

NORTH CAROLINA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 306...WW 307...



DISCUSSION...AFTERNOON SURFACE OBSERVATIONS AND OBJECTIVE ANALYSIS

GUIDANCE INDICATE THE ENVIRONMENT FROM SOUTHEAST VA AND SOUTHERN

MARYLAND SOUTH ACROSS EASTERN NC HAS BECOME VERY UNSTABLE WITH

MLCAPE VALUES FROM 2500 TO OVER 4000 J/KG...AND DCAPE WELL IN EXCESS

OF 1000 J/KG. MEANWHILE...AREA VWP/S SHOW DEEP-LAYER WLY FLOW

INCREASING TO 50KT AT 3 KM AGL. GIVEN THIS COMBINATION OF STRONG TO

LOCALLY EXTREME CAPE...INCREASING SHEAR...AND ONGOING ORGANIZING

CONVECTIVE LINE AND FORCING IN THE PROCESS OF CRESTING THE

APPALACHIANS...A REGIONAL SEVERE WEATHER OUTBREAK APPEARS QUITE

LIKELY.



OVER THE NEXT SEVERAL HOURS EXPECT MULTICELL CLUSTERS/LINE SEGMENTS

AND SUPERCELLS TO SPREAD EAST ACROSS THE UNSTABLE WARM SECTOR WITH A

WIDE RANGE OF SEVERE WEATHER INCLUDING POTENTIALLY DAMAGING HAIL AND

PERHAPS EVEN A TORNADO OR TWO. AT THIS TIME...THE GREATEST HAZARD

APPEARS TO BE WIDESPREAD HIGH WINDS WITH THE CHANCE FOR DAMAGING

GUSTS IN EXCESS OF HURRICANE FORCE /65KT/. THE CORRIDOR OF GREATEST

SEVERE POTENTIAL WILL BE AROUND THE VA/NC BORDER AREA WITH A

DECREASING CHANCE FOR HIGHER-END SEVERE AND LOWER STORM COVERAGE

POSSIBLE WITH SOUTHWESTWARD EXTENT.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM

MOTION VECTOR 29040.





...CARBIN

