The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains and arklatex this afternoon and tonight.... Please read the latest public statement about this event. View What is a Watch? clip.
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 220059
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CDT TUE MAY 21 2013
VALID 220100Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE TN
VALLEY...LOWER MS VALLEY AND SRN PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN
NY...VT...NH AND MA...
...TN VALLEY/LOWER MS VALLEY/SRN PLAINS...
SEVERAL LINEAR MESOSCALE CONVECTIVE SYSTEMS ARE ONGOING FROM WRN TN
SWWD ACROSS NW MS INTO NW LA AND EAST TX. THE STORMS ARE LOCATED ON
THE NWRN EDGE OF A CORRIDOR OF MODERATE INSTABILITY. MLCAPE VALUES
ACROSS THE WARM SECTOR ARE ESTIMATED IN THE 2000 TO 3000 J/KG RANGE
FROM THE SRN PLAINS ENEWD INTO THE LOWER MS VALLEY. THIS ALONG WITH
LARGE-SCALE ASCENT ASSOCIATED WITH AN UPPER-LEVEL TROUGH IN THE SRN
PLAINS WILL CONTINUE TO SUPPORT MCS DEVELOPMENT THIS EVENING. IN
ADDITION...A 50 TO 65 KT MID-LEVEL JET IS ANALYZED OVER THE ERN
PARTS OF THE SRN PLAINS. THIS FEATURE IS CREATING MODERATE DEEP
LAYER SHEAR PROFILES ACROSS MUCH OF THE WARM SECTOR WHICH WILL HELP
TO MAINTAIN A SEVERE THREAT THROUGH THE MID EVENING. REGIONAL
WSR-88D VWPS ACROSS THE WARM SECTOR SHOW UNIDIRECTIONAL WINDS IN THE
BOUNDARY LAYER WITH ABOUT 20 TO 30 KT OF FLOW. THIS COINCIDING WITH
0-3 KM LAPSE RATES OF 7.0 TO 7.5 C/KM SHOULD BE FAVORABLE FOR
DAMAGING WIND GUSTS WITH THE MORE ORGANIZED BOWING LINE SEGMENTS. AN
ISOLATED THREAT FOR HAIL AND A BRIEF TORNADO WILL BE POSSIBLE WITH
ROTATING CELLS ELEMENTS. HOWEVER...THE LOW-LEVEL WIND PROFILES
APPEAR MOST FAVORABLE FOR DAMAGING WIND GUSTS.
....NRN APPALACHIAN MTNS...
THE LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL RIDGE IN PLACE
ACROSS THE APPALACHIAN MTNS WITH A DISTURBANCE MOVING EWD ACROSS THE
TOP OF THE RIDGE INTO NY AND NEW ENGLAND. THIS FEATURE IS SUPPORTING
AN ARCHING LINE OF THUNDERSTORMS EXTENDING SWWD ACROSS NERN...CNTRL
AND SRN NY. MLCAPE VALUES AHEAD OF THE LINE ARE ESTIMATED TO BE IN
THE 500 TO 1500 J/KG RANGE. THIS COMBINED WITH MODERATE TO STRONG
DEEP LAYER SHEAR PROFILES WILL HELP SUPPORT THE LINE FOR SEVERAL
MORE HOURS THIS EVENING. THE ALBANY NY WSR-88D VWP SHOWS DIRECTIONAL
TURNING BELOW 2 KM AGL WITH 25 TO 30 KT OF FLOW IN THE LOW TO
MID-LEVELS. THE LOW-LEVEL WIND APPEARS FAVORABLE FOR WIND DAMAGE AS
A BOWING LINE SEGMENT MOVES EWD ACROSS ERN NY...VT...NH AND MA OVER
THE NEXT FEW HOURS. HAIL WILL ALSO BE POSSIBLE WITH THE MORE INTENSE
CELLS.
..BROYLES.. 05/22/2013
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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