SWODY1
SPC AC 111955
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 PM CDT SUN APR 11 2010
VALID 112000Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EVENING
OVER PARTS OF WRN/SWRN TX AND FAR SWRN OK...
...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT OVER PARTS OF THE LOWER
RIO GRANDE VALLEY...
...WRN/SWRN TX INTO FAR SWRN OK...
THE 15 PERCENT HAIL AND CATEGORICAL SLIGHT RISK LINES HAVE BEEN
ADJUSTED TO BETTER FIT WITH WHERE THE STRONGEST AIR MASS
DESTABILIZATION IS OCCURRING.
THE COUPLING OF DAYTIME HEATING WITH THE NWD RETURN OF AN
INCREASINGLY MOIST AIR MASS THROUGH THE LOWER RIO GRANDE VALLEY INTO
WRN TX IS SUPPORTING AIR MASS DESTABILIZATION THIS AFTERNOON WHERE
MLCAPE HAS INCREASED TO 1000-1500 J/KG. INITIAL TSTM FORMATION IS
OCCURRING ALONG THE WRN EDGE OF THE INSTABILITY AXIS FROM S OF CVS
TO NEAR MRF. ADDITIONAL STORM DEVELOPMENT IS EXPECTED THROUGH THE
REMAINDER OF THE DIURNAL HEATING CYCLE FROM VICINITY OF RETREATING
WEAK WARM FRONT OVER THE SRN TX PNHDL SWWD INTO SWRN TX.
HERE...FURTHER HEATING/DESTABILIZATION IN CONJUNCTION WITH THE
INFLUENCE OF A WEAK MIDLEVEL VORTICITY MAXIMUM CURRENTLY MOVING
THROUGH FAR WRN TX AND SERN NM SHOULD SUPPORT SCATTERED MULTICELL
STORM CLUSTERS CAPABLE OF MAINLY SEVERE HAIL.
STORMS SHOULD TEND TO WEAKEN LATER THIS EVENING AS THE BOUNDARY
LAYER COOLS AND STABILIZES.
...LOWER RIO GRANDE VALLEY...
NO CHANGES MADE TO CURRENT FORECAST.
...S FL...
ONLY A SLIGHT ADJUSTMENT HAVE BEEN MADE TO THE FIVE PERCENT WIND
PROBABILITY TO ACCOMMODATE THE LOCATION OF THE MCS CURRENTLY
PROPAGATING SWD THROUGH THE FAR SRN PENINSULA.
..MEAD.. 04/11/2010
.PREV DISCUSSION... /ISSUED 1117 AM CDT SUN APR 11 2010/
...SRN HI PLAINS...
THE STEERING FLOW WILL REMAIN RATHER WEAK ACROSS THE SRN
PLAINS...OTRW CONDITIONS ARE BECOMING INCREASINGLY FAVORABLE FOR
DEVELOPMENT OF STRONG/SEVERE THUNDERSTORMS BEGINNING THIS AFTERNOON.
GULF MOISTURE CONTINUES TO SPREAD N/NNWWD UNDER AN EXTENSIVE EML
WHICH COVERS MUCH OF THE PLAINS.
MORNING CONVECTIVE CLOUDINESS SHOULD GRADUALLY DISSIPATE FROM THE W
ACROSS SWRN TX WHICH WILL ALLOW HEATING AND SURFACE INSTABILITY TO
INCREASE. WITH DEWPOINTS WELL INTO THE 50S BY LATE AFTERNOON AS
TEMPS CLIMB THRU THE 70S...MLCAPES AOA 2000 J/KG WILL DEVELOP ACROSS
THE SRN PANHANDLE SWWD TO THE ERN SLOPES OF THE DAVIS MTNS. WITH
THE STEEP LAPSE RATES AND RELATIVELY COOL MID LEVELS...HAIL WILL BE
COMMON WITH THE STRONGEST UPDRAFTS. WHILE OVERALL SHEAR NOT
SUPPORTIVE OF SUPERCELLS...THE UNSTABLE ENVIRONMENT FAVORS SOME
ROTATION IN STRONGEST STORMS WHICH WILL RAISE THE THREAT FOR BOTH
LARGE HAIL AND LOCALIZED DAMAGING DOWNBURSTS.
INITIATION EXPECTED TO OCCUR VICINITY DISSIPATING FRONTAL ZONE THAT
LIES FROM SRN TX PANHANDLE WWD INTO ERN NM. THE CINH SHOULD WEAKEN
FIRST NEAR THE WRN EDGE OF MOISTURE GRADIENT FROM SERN NM TO DAVIS
MTNS. STORMS WILL MOVE ONLY SLOWLY E/SEWD IN THE WEAK FLOW
ENVIRONMENT POSSIBLY CONTINUING A MARGINAL HAIL/WIND THREAT AFTER
SUNSET INTO W CENTRAL TX PRIOR TO WEAKENING TO BELOW SEVERE.
...LOWER RIO GRANDE VALLEY...
DEEP MOISTURE IS SPREADING UP THE LWR RIO GRANDE VALLEY AS OBSERVED
ON THE 12Z BRO SOUNDING WITH PW/S OF 1.8 INCHES. AGAIN AN EML
OVERLAYS S TX WITH A STOUT CAP NOTED ON THE DRT SOUNDING. HEATING
OF THE HIGHER TERRAIN W OF THE LOWER RIO GRANDE IN MEXICO EXPECTED
TO INITIATE STRONG THUNDERSTORMS DURING THE AFTERNOON. BY THIS
EVENING MODELS INDICATE LOW LEVEL SELY JET INCREASES TO 30-35 KTS
LWR RIO GRANDE VALLEY WHICH SUPPORTS THE STORMS IN MEXICO ORGANIZING
INTO CLUSTERS AND POSSIBLE BOWS AS THEY MOVE SEWD ACROSS THE RIVER
INTO SRN TX. WITH MLCAPES TO 2000 J/KG AND BULK SHEAR INCREASING TO
40-50KT IN CONCERT WITH THE LOW LEVEL JET...APPEARS THERE WILL BE A
THREAT OF DAMAGING WINDS ASSOCIATED WITH THE ACTIVITY MOVING ACROSS
LWR RIO GRANDE TONIGHT INTO S TX ALONG WITH LARGE HAIL. A SLIGHT
RISK HAS BEEN ADDED THIS AREA.
...S FL...
A SLOW MOVING MCS HAS DEVELOPED VICINITY THE SWRN FL COAST THIS AM
IN RESPONSE TO THE PASSAGE OF A MID LEVEL TROUGH FROM THE ERN GULF
AND AN INCREASINGLY UNSTABLE ENVIRONMENT S FL. COOL MID LEVEL
TEMPS...-12C AT 500 MB...SUPPORT HAIL WITH THE STRONGEST CORES AS
WELL AS STRONG WIND GUSTS. ACTIVITY EXPECTED TO REMAIN GENERALLY
BELOW SEVERE LEVELS...AS THE MCS CONTINUES SEWD ACROSS SRN FL TOWARD
THE UPPER KEYS THIS AFTERNOON.
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