National Weather Service United States Department of Commerce

Potential Tornado Outbreak Today; Atmospheric River for the Northwest

Severe thunderstorm outbreak with tornadoes, wind damage, and large hail are expected today from parts of the southern Plains, eastward into the lower Mississippi Valley and central Gulf Coast states. Several long-track strong tornadoes are expected. Furthermore, excessive rainfall potential exists with flash flooding possible. For the western US, heavy precipitation and strong winds continue. Read More >

 

Tuesday March 24, 2015

 

...PENNSYLVANIA SEVERE WEATHER AWARENESS WEEK...

THIS IS SEVERE WEATHER AWARENESS WEEK IN PENNSYLVANIA.

NOW IS THE TIME TO PREPARE FOR THE UPCOMING SEVERE WEATHER SEASON.

WE ARE COVERING A DIFFERENT SAFETY TOPIC EACH DAY OF THIS WEEK.

OUR SEVERE WEATHER AND WEATHER SAFETY TOPIC FOR TODAY IS...
SEVERE THUNDERSTORMS.

WE WILL COVER WHAT CLASSIFIES A THUNDERSTORM AS SEVERE...AND WHAT
THE DIFFERENCES ARE BETWEEN A SEVERE THUNDERSTORM WATCH AND A SEVERE
THUNDERSTORM WARNING.  WE WILL ALSO GIVE YOU INFORMATION ON WHAT TO
DO WHEN A WATCH OR WARNING IS ISSUED FOR YOUR AREA.

WHAT IS A SEVERE THUNDERSTORM?

A THUNDERSTORM IS CONSIDERED SEVERE IF IT PRODUCES WIND GUSTS
OF 58 MILES AN HOUR OR HIGHER...AND/OR HAIL ONE INCH IN
DIAMETER OR LARGER. THOSE HAILSTONES ARE ABOUT THE SIZE OF A
QUARTER. SEVERE THUNDERSTORMS ARE OFTEN ACCOMPANIED BY
TORRENTIAL DOWNPOURS AND FREQUENT LIGHTNING. THEY CAN ALSO
PRODUCE BRIEF...WEAK TORNADOES. THE DAMAGE FROM THE STRONG WIND
GUSTS OF A SEVERE THUNDERSTORM CAN BE JUST AS BAD AS THE DAMAGE
MADE BY A TORNADO. SEVERE THUNDERSTORMS ARE MUCH MORE COMMON
THAN TORNADOES.

WHAT IS A SEVERE THUNDERSTORM WATCH?

A SEVERE THUNDERSTORM WATCH IS ISSUED IN ORDER TO ALERT YOU THAT
THUNDERSTORMS WITH DAMAGING WINDS AND LARGE HAIL ARE EXPECTED TO
DEVELOP CLOSE TO YOUR LOCATION. A WATCH BY ITSELF DOES NOT MEAN
THAT SEVERE WEATHER IS ACTUALLY OCCURRING YET...IT MEANS THAT
SEVERE WEATHER IS EXPECTED TO HAPPEN CLOSE BY. A SEVERE
THUNDERSTORM WATCH USUALLY COVERS AN AREA AS LARGE AS A STATE...
AND IS IN EFFECT FOR SEVERAL HOURS...EXPIRING ONLY WHEN THE
THUNDERSTORMS ARE EXPECTED TO END.

WHAT SHOULD YOU DO WHEN A SEVERE THUNDERSTORM WATCH IS ISSUED?

GO ABOUT YOUR NORMAL ACTIVITIES...BUT WATCH THE SKY AROUND YOU
FOR DEVELOPING STORMS. PERIODICALLY CHECK NOAA WEATHER RADIO OR
OTHER MEDIA OUTLETS FOR FORECAST UPDATES AND POSSIBLE WARNINGS.
KNOW WHICH COUNTY YOU LIVE IN...AND WHICH ONES BORDER YOUR
COMMUNITY. THINK OF A SAFE PLACE TO BE AND PLAN A ROUTE WHICH
YOU CAN USE TO GET THAT SAFE PLACE QUICKLY.

WHAT IS A SEVERE THUNDERSTORM WARNING?

A SEVERE THUNDERSTORM WARNING MEANS A SEVERE THUNDERSTORM IS
OCCURRING AND IS GOING TO MOVE THROUGH YOUR LOCATION SOON. IT IS
YOUR SIGNAL THAT YOU WILL NEED TO TAKE QUICK ACTION TO PROTECT YOUR
LIFE AND PROPERTY.  SEVERE THUNDERSTORM WARNINGS ARE ISSUED BY THE
NATIONAL WEATHER SERVICE WHEN METEOROLOGISTS DETECT A SEVERE
THUNDERSTORM USING DOPPLER RADAR OR WHEN DAMAGE HAS BEEN REPORTED BY
SKYWARN WEATHER SPOTTERS.

TYPICALLY...A SEVERE THUNDERSTORM WARNING WILL BE ISSUED FOR AN AREA
AS BIG AS A COUNTY OR TWO...AND FOR A PERIOD OF UP TO ONE HOUR. IN
THE TEXT OF THE WARNING STATEMENT...WE TRY TO MAKE A SPECIFIC LIST
OF TOWNS THAT ARE LIKELY TO BE IN THE PATH OF THE STORM. YOU SHOULD
LISTEN TO HEAR IF COMMUNITIES OR LANDMARKS NEAR YOU ARE MENTIONED IN
THE WARNING.

WHAT SHOULD YOU DO WHEN A SEVERE THUNDERSTORM WARNING IS ISSUED FOR
YOUR LOCATION?

IF YOU ARE OUTDOORS...GET INSIDE YOUR HOME...A STRONG BUILDING...
OR IN YOUR CAR. BOATERS SHOULD HEAD TO SHORE IMMEDIATELY.

WHEN INDOORS...GO TO AN INTERIOR ROOM ON THE LOWEST LEVEL. STAY AWAY
FROM WINDOWS AND EXTERIOR DOORS. DO NOT USE ELECTRICAL APPLIANCES
AND AVOID USING THE TELEPHONE...AS LIGHTNING CAN TRAVEL THROUGH
ELECTRICAL AND TELEPHONE LINES.

IF YOU ARE DRIVING...SAFELY PULL OVER TO THE SIDE OF THE ROAD UNTIL
THE STORM PASSES. HEAVY RAIN FALLING FROM ANY THUNDERSTORM CAN FLOOD
ROADS QUICKLY...SO NEVER TRY TO DRIVE THROUGH AN AREA WHERE WATER
COVERS THE ROAD...EVEN IF YOU THINK IT IS SHALLOW. WATER MAY SWEEP
YOUR VEHICLE AWAY IF YOU ATTEMPT TO DRIVE THROUGH IT.

FOR ADDITIONAL THUNDERSTORM AND SEVERE WEATHER SAFETY INFORMATION
CHECK OUT OUR WEB PAGE AT:

https://weather.gov

OUR WEATHER SAFETY TOPICS FOR THE REST OF THE WEEK WILL BE...
WEDNESDAY...FLASH FLOOD SAFETY.
THURSDAY...RIVER FLOOD SAFETY.
FRIDAY...SKYWARN SEVERE WEATHER SPOTTERS.