Monday, July 25, 2011

Tornado Warning for Norfolk, VA Cancelled

July 25: Tornado Warning: Norfolk, VA


THE NATIONAL WEATHER SERVICE IN WAKEFIELD HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEASTERN CITY OF NEWPORT NEWS IN VIRGINIA...
  NORTHWESTERN CITY OF NORFOLK IN SOUTHEAST VIRGINIA...
  NORTHWESTERN CITY OF PORTSMOUTH IN SOUTHEAST VIRGINIA...

* UNTIL 900 PM EDT

* AT 821 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED 5 MILES WEST OF NORFOLK NAVAL AIR STATION...AND
  MOVING EAST AT 15 MPH.

* THIS DANGEROUS STORM WILL BE NEAR...
  NORFOLK NAVAL AIR STATION AND WILLOUGHBY SPIT AROUND 840 PM EDT.
  WARDS CORNER AND OCEAN VIEW AROUND 850 PM EDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE... OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

HEAVY RAINFALL MAY OBSCURE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR
THE TORNADO. TAKE COVER NOW.

TORNADOES ARE DIFFICULT TO SEE AND CONFIRM AT NIGHT. TAKE COVER NOW.

Apologies

We did not post much today, mostly because of other activities and the fact that not much, other than some severe storms in the Dakotas, is occurring in the country today.

Tomorrow, we will be back in action.

Mesoscale Discussion #1730 (Outlook Upgrade, Severe T-Storm Watch)


AREAS FROM NERN OH ACROSS WRN NY AND NY SRN TIER TO THE MOHAWK
   VALLEY...AS WELL AS NWRN PA...WILL BE INCLUDED IN A SLGT RISK AREA
   WITH THE ISSUANCE OF THE NEXT SPC DAY 1 OTLK BY 1630 UTC/1230 EDT.
   FURTHERMORE...A WATCH MAY BE NEEDED ACROSS SOME OF THIS AREA BEFORE
   NOON EDT.
   
   VSBL SATL IMAGERY DEPICTS AN AXIS OF RELATIVELY CLEAR SKIES FROM OH
   ENEWD ACROSS THE SRN TIER OF NY. EXPECT THAT SURFACE HEATING ACROSS
   THIS CORRIDOR...ALONG WITH INCREASINGLY FAVORABLE LARGE SCALE ASCENT
   ASSOCIATED WITH AN APPROACHING UPPER TROUGH...WILL SUPPORT THE
   CONTINUED DEVELOPMENT OF SEVERE TSTMS INTO THE AFTERNOON. COINCIDENT
   WITH THE INCREASE IN INSTABILITY WITHIN THE VERY MOIST AND WARMING
   AIRMASS...DEEP LAYER SHEAR WILL BECOME INCREASINGLY STRONG AS
   40-50KT MID-LEVEL SPEED MAX SPREADS EAST FROM THE UPPER GREAT LAKES.
   THIS WILL PROMOTE LONGER-LIVED/ORGANIZED UPDRAFTS LIKELY TAKING THE
   FORM OF LINE/BOWING SEGMENTS CAPABLE OF PRODUCING DAMAGING WINDS AS
   WELL AS SOME HAIL.
   
   IF LATEST TRENDS WITH THE BROKEN PRE-FRONTAL LINE OF STORMS NOW
   MOVING INTO WRN NY CONTINUE...A SVR TSTM WATCH WILL ALSO BE
   COORDINATED SHORTLY FOR PARTS OF THE REGION.

July 25 Severe Weather Briefing

Slight risk of severe weather for Montana and western SD.

Discussion... Observation of 11z HRRR short-range model indicates a strong bowing severe thunderstorm cluster will develop on the eastern fringes of Wyoming and move into South Dakota. Originally in Wyoming, the storms will start out possibly supercellular before congealing into the bowing line. That said, there will be a more elevated threat of tornadoes in NE Wyoming, then a skyrocketing high wind threat into South Dakota.
11z HRRR doesn't indicate any severe weather for Montana, but does introduce moderate showers and thunderstorms in ragged clusters. Unfortunately, 12z RR and 13z RUC are both updating at this time, so we cannot get their inputs.
In summary, South Dakota has a good threat for severe weather for today.