[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 130602
SWODY1
SPC AC 130601

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0101 AM CDT THU JUL 13 2006

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF VA...WV AND NRN
NC...

...GREAT PLAINS...
A NRN ROCKIES UPPER-TROUGH IS FORECAST TO MOVE QUICKLY EWD ACROSS
THE HIGH PLAINS INTO THE NRN AND CNTRL PLAINS THIS AFTERNOON.
LARGE-SCALE ASCENT WILL RAPIDLY INCREASE ACROSS THE PLAINS WITH A
LINE OF THUNDERSTORMS QUICKLY DEVELOPING ALONG THE WRN EDGE OF AN
AXIS OF MODERATE TO STRONG INSTABILITY BY MID-AFTERNOON. FORECAST
SOUNDINGS SHOW INCREASING VERTICAL SHEAR PROFILES AS A 40-50 KT
MID-LEVEL JET NOSES INTO THE REGION. IN ADDITION...0-6 KM SHEAR
VALUES BETWEEN 30 AND 40 KT AS SHOWN ON FORECAST SOUNDINGS SUGGEST
SEVERE MULTICELL LINE SEGMENTS AND/OR SUPERCELLS WILL BE POSSIBLE AS
STORMS INCREASE IN COVERAGE LATE THIS AFTERNOON. ALTHOUGH THE MODELS
DIFFER CONCERNING THE SRN EXTENT OF A LINEAR MCS...THE WRF MODEL
SEEMS REASONABLE DEVELOPING A LINE FROM ERN SD EXTENDING SWD ACROSS
ERN NEB. LOW-LEVEL LAPSE RATES ARE FORECAST TO BE VERY STEEP (0-3 KM
LAPSE RATES > 9.0 C/KM) WHICH WILL LIKELY ENHANCE THE WIND DAMAGE
POTENTIAL. VERY STRONG WIND GUSTS WILL BE POSSIBLE WITH ANY BOWING
SEGMENTS IN THE LINE. HAIL WILL ALSO BE LIKELY WITH THE STRONGER
ELEMENTS IN THE LINE AND THE GREATEST POTENTIAL FOR LARGE HAIL
SHOULD EXIST WITH SUPERCELLS THAT DEVELOP AHEAD OF OR EMBEDDED IN
THE LINE. THE LINEAR MCS SHOULD MOVE ESEWD ACROSS THE SIOUX FALLS SD
AND OMAHA NEB AREAS BY EARLY EVENING LIKELY REACHING WRN IA...NW MO
AND NE KS BY LATE EVENING. A SEVERE THREAT MAY CONTINUE OVERNIGHT
ESPECIALLY CONSIDERING STRONG INSTABILITY IS FORECAST TO BE IN PLACE
THROUGH THIS EVENING.

FURTHER SOUTH ACROSS SW KS...THE ERN TX PANHANDLE AND NW OK...THE
MODELS FORECAST WEAKER LARGE-SCALE ASCENT AND A STRONGER CAPPING
INVERSION THAN AREAS FURTHER NORTH WHICH SHOULD KEEP THUNDERSTORM
COVERAGE MORE ISOLATED. ALTHOUGH THE HAIL POTENTIAL MAY BE LESS DUE
TO THE WARMER AIR ALOFT...A POTENTIAL FOR WIND DAMAGE SHOULD STILL
EXIST WITH THE STRONGER CELLS DUE TO STEEP LOW-LEVEL LAPSE RATES AND
MODERATE VERTICAL SHEAR SHOWN ON FORECAST SOUNDINGS.

...VA/NC...
WATER VAPOR IMAGERY CURRENTLY SHOWS A SHORTWAVE TROUGH OVER THE OH
VALLEY WITH A NOTABLE DRY PUNCH ADVANCING EWD ACROSS NRN IL AND NRN
IND ATTM. MODEL FORECASTS MOVE THIS FEATURE EWD ACROSS THE CNTRL
APPALACHIAN MTNS TODAY INCREASING LARGE-SCALE ASCENT ACROSS VA AND
NRN NC LATE THIS AFTERNOON. SFC DEWPOINTS NEAR 70 F IN THE
APPALACHIAN FOOTHILLS AND COASTAL PLAINS SHOULD ALLOW MODERATE TO
STRONG INSTABILITY TO DEVELOP BY MIDDAY. SCATTERED THUNDERSTORMS
SHOULD INITIATE AND MOVE EWD ACROSS THE REGION DURING THE AFTERNOON
AHEAD OF THE APPROACHING SHORTWAVE TROUGH. VERTICAL SHEAR PROFILES
ARE FORECAST TO RANGE BETWEEN 20 AND 30 KT AND SHOULD BE STRONGEST
IN VA AS THE UPPER-TROUGH APPROACHES. THIS COMBINED WITH THE STRONG
INSTABILITY SHOULD BE SUFFICIENT FOR ISOLATED SEVERE THUNDERSTORMS.
HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH THE STRONGER MULTICELL
LINE SEGMENTS LATE THIS AFTERNOON INTO EARLY THIS EVENING.

...MID-MS VALLEY...
A LARGE WARM SECTOR CURRENTLY EXISTS ACROSS THE MID MS VALLEY WHERE
SFC DEWPOINTS ARE IN THE UPPER 60S AND LOWER 70S F. THE LOW-LEVEL
MOISTURE SHOULD REMAIN IN PLACE TODAY ALLOWING STRONG INSTABILITY TO
DEVELOP AS SFC TEMPS WARM. ALTHOUGH FORECAST SOUNDINGS ACROSS THE
REGION SHOW RELATIVELY WEAK SHEAR PROFILES (0-6 KM SHEAR OF 10-20
KT)...THE STRONG INSTABILITY AND STEEP LOW-LEVEL LAPSE RATES SHOULD
BE SUFFICIENT FOR A FEW MARGINALLY SEVERE STORMS. STRONG WIND GUSTS
WILL BE MOST LIKELY WITH SHORT MULTICELL LINE SEGMENTS NEAR OR JUST
AFTER PEAK HEATING.

..BROYLES/GRAMS.. 07/13/2006