Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
000
ACUS02 KWNS 251726
SWODY2
SPC AC 251725

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CDT SAT APR 25 2015

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SRN
PLAINS STATES...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE GULF STATES
REGION...

...SUMMARY...
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE
SOUTHERN PLAINS SUNDAY AFTERNOON AND CONTINUE INTO THE OVERNIGHT
HOURS.  ISOLATED STRONG STORMS MAY ALSO DEVELOP ACROSS THE REMAINDER
OF THE GULF COAST STATES.

...SYNOPSIS...
A MID- TO UPPER-LEVEL LOW/TROUGH WILL MIGRATE FROM THE FOUR CORNERS
EWD INTO THE SRN HIGH PLAINS DURING THE PERIOD.  MEANWHILE FARTHER
E...A STATIC PATTERN FEATURING A MID-LEVEL ANTICYCLONE OVER THE MID
MO VALLEY WILL BE LOCATED TO THE W OF A SERIES OF DISTURBANCES
MAINTAINING A LARGE-SCALE TROUGH OVER THE ERN SEABOARD.  A COLD
FRONT WILL SAG SWD ACROSS PORTIONS OF THE CNTRL STATES INTO THE SRN
PLAINS AND THE DEEP SOUTH WITH THE WWD EXTENSION OF THE FRONT
INTERSECTING A DEVELOPING AREA OF SURFACE LOW PRESSURE OVER THE SRN
HIGH PLAINS.  A NORTH-SOUTH DRYLINE WILL LIKELY SHARPEN ACROSS
PORTIONS OF W-CNTRL AND NW TX DURING THE DAY AND SERVE AS A FOCUS
FOR THUNDERSTORMS BEGINNING IN THE AFTERNOON.

...SRN PLAINS...
A RESERVOIR OF RICH LOW-LEVEL MOISTURE SHUNTED TO THE TX COASTAL
PLAIN BY SUNDAY MORNING WILL ADVANCE NWWD INTO CNTRL TX DURING THE
DAY IN RESPONSE TO LEE CYCLOGENESIS IN THE SRN HIGH PLAINS.  STRONG
HEATING IS FORECAST OVER SWRN TX AND A REINVIGORATED EML WILL LIKELY
OVERSPREAD THE W EDGE OF THE MOIST AXIS ACROSS CNTRL TX DURING THE
DAY LEADING TO THE DEVELOPMENT OF A MODERATE TO VERY UNSTABLE
BOUNDARY LAYER /1500-3000 J PER KG MLCAPE/ ACROSS CNTRL TX.  AS THE
CAP WEAKENS DURING THE AFTERNOON...WEAK HEIGHT FALLS WILL GRADUALLY
OVERSPREAD W-CNTRL TX AS THE NOSE OF A 80-KT H5 SPEED MAX OVER NRN
CHIHUAHUA MOVES INTO SW TX BY LATE AFTERNOON.  ISOLD TO WIDELY SCTD
STORMS WILL PROBABLY DEVELOP NEAR THE DRYLINE AND THE VEERING AND
STRENGTHENING WINDS WITH HEIGHT WILL FAVOR SUPERCELLS CAPABLE
PRIMARILY OF ISOLD LARGE TO VERY LARGE HAIL/STRONG WINDS WITH
PERHAPS AN ISOLD TORNADO RISK AS STORMS MOVE EWD INTO RICHER
MOISTURE TO THE E OF THE DRYLINE.

FARTHER N...MODELS SHOW AN ELY-COMPONENT AND UPSLOPE FLOW INVOF THE
SWD SAGGING FRONTAL ZONE OVER OK INTO THE TX PANHANDLE.  INCREASING
UPPER-LEVEL FORCING FOR ASCENT COUPLED WITH STRONG HEATING AND
CONVERGENCE ALONG THE ARCING DRYLINE INTO FAR SWRN OK INTO THE TX
PANHANDLE WILL PROBABLY ERODE THE CAP BY MID-LATE AFTERNOON.
FORECAST SOUNDINGS SHOW MODERATE BUOYANCY DEVELOPING WITHIN AN AXIS
OF 50S DEWPOINTS.  STRONG VEERING WINDS WITH HEIGHT WILL FAVOR THE
DEVELOPMENT OF SUPERCELLS WITH THE MORE ROBUST UPDRAFTS.  COOL
MID-LEVEL TEMPS /-16 TO -18 DEG C AT H5/ WOULD SUPPORT LARGE TO VERY
LARGE HAIL GROWTH DURING THE MATURE PHASE OF THE STORM LIFECYCLE.
AS THE UPPER-LEVEL TROUGH CONTINUES TO MOVE INTO THE REGION FROM THE
W DURING THE EVENING/OVERNIGHT...ADDITIONAL ISOLD STRONG TO SEVERE
STORM DEVELOPMENT /PRIMARILY HAIL/ IS POSSIBLE OWING TO THE
STRENGTHENING OF WAA ACROSS THE RED RIVER VALLEY.

...GULF COAST AND S ATLANTIC COAST STATES...
ISOLATED STRONG STORMS MAY ALSO DEVELOP ACROSS THE REMAINDER OF THE
GULF STATES SUNDAY.  STORM COVERAGE WILL LIKELY REMAIN ISOLD GIVEN
WEAK RIDGING ALOFT OVER THE CNTRL GULF COAST.  THE COMBINATION OF
POSSIBLE FOCUSING FEATURES SUCH AS SEA BREEZE AND THE SWD-ADVANCING
FRONTAL ZONE MAY AID IN INITIATING STORM DEVELOPMENT.  STRONG
HIGH-LEVEL FLOW AND ADEQUATE LOW-LEVEL MOISTURE MAY YIELD AN ISOLD
HAIL/WIND RISK WITH THE STRONGEST STORMS.

..SMITH.. 04/25/2015



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.