DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 291955
SWODY1
SPC AC 291953

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT TUE OCT 29 2013

VALID 292000Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...TRANS PECOS AND PERMIAN BASIN AREA OF TX...
AN UPPER IMPULSE NOTED ON WATER VAPOR LOOP WAS MOVING ACROSS NWRN MX
TOWARDS THE TX BIG BEND. DESPITE THICK CIRRUS STREAMING NWD ACROSS
THE REGION...TEMPERATURES HAVE HEATED INTO THE UPPER 70S/LOWER 80S F
AMIDST LOW 60S F DEWPOINTS. AS THE UPPER IMPULSE APPROACHES...THE
POTENTIAL FOR LOCALLY ENHANCED TSTM DEVELOPMENT SHOULD INCREASE THIS
AFTERNOON THROUGH THE EARLY EVENING...PARTICULARLY INVOF THE HIGHER
TERRAIN OF SW TX AND JUST ACROSS THE INTERNATIONAL BORDER. A COUPLE
SUPERCELLS COULD EVOLVE FROM MORE VIGOROUS UPDRAFTS GIVEN AROUND 40
KT OF DEEP-LAYER SHEAR...POSING AN ISOLATED THREAT FOR LARGE HAIL
AND/OR DMGG WINDS...BUT THE THREAT REMAINS TOO LOCALIZED/UNCERTAIN
TO WARRANT A RISK UPGRADE.

...SRN/CNTRL PLAINS TODAY THROUGH EARLY WED...
SOME CLEARING HAS OCCURRED /PER VISIBLE SATELLITE IMAGERY/ ACROSS
PARTS OF NW TX AND THE TX ROLLING PLAINS...WITH TEMPERATURES HEATING
INTO THE LOW 80S F. HOWEVER...MINISCULE SFC CONVERGENCE WITHIN
NEARLY UNIFORM S-SWLY FLOW...ALONG WITH THE LIKELY PRESENCE OF AT
LEAST WEAK CINH...WILL PROVE DIFFICULT FOR CONVECTIVE INITIATION TO
OCCUR THROUGH THE LATE AFTERNOON/EARLY EVENING. THUS...ANY SVR
POTENTIAL DURING THIS TIME PERIOD REMAINS CONDITIONAL...DESPITE
FAVORABLE ENVIRONMENTAL SHEAR PROFILES AND STEEP MIDLEVEL LAPSE
RATES.

LATER TONIGHT...CONVECTIVE POTENTIAL SHOULD INCREASE ACROSS THE
PLAINS AS A LLJ STRENGTHENS AND LARGE-SCALE HEIGHT FALLS OVERSPREAD
THE REGION. A FAIRLY CONSISTENT SIGNAL IN FORECAST MODELS IS PRESENT
INDICATING CONVECTION /PRIMARILY ELEVATED/ WILL DEVELOP INVOF THE
NOSE OF THE LLJ FROM THE NRN TX PANHANDLE INTO SWRN KS AFTER 03Z.
STEEP MIDLEVEL LAPSE RATES AND MUCAPE VALUES NEAR 2000 J/KG...ALONG
WITH AROUND 40 KT OF CLOUD-LAYER SHEAR...COULD SUPPORT SOME
POTENTIAL FOR LARGE HAIL AFTER SUNSET. ACTIVITY MAY EXPAND EWD
OVERNIGHT INTO EARLY WED MORNING...PERHAPS AS FAR EWD AS CNTRL KS/OK
AND N TX.

..ROGERS.. 10/29/2013

.PREV DISCUSSION... /ISSUED 1129 AM CDT TUE OCT 29 2013/

...SYNOPSIS...
SLOWLY PROGRESSIVE SPLIT FLOW PATTERN WILL PERSIST ACROSS THE CONUS
THROUGH WED...WITH THE MAIN FEATURE OF NOTE BEING
BROAD...POSITIVE-TILT CLOSED LOW/TROUGH NOW OVER NE NV. THE
LOW/TROUGH SHOULD CONTINUE E ACROSS THE GRT BASIN LATER
TODAY/TNGT...WITH THE TROUGH AXIS REACHING A N CNTRL WY TO NW AZ
LINE BY 12Z WED. THIS WILL RESULT IN A SLIGHT STRENGTHENING AND
BACKING OF EXISTING SW MID/UPR-LVL FLOW OVER THE CNTRL/SRN PLNS TNGT
AND EARLY WED.

IN THE MEAN TIME...LARGE-SCALE FORCING FOR ASCENT ATOP THE
MOISTENING BOUNDARY LAYER ACROSS THE SRN HALF OF THE PLNS IS
EXPECTED TO REMAIN NEUTRAL AT BEST THROUGH EARLY TNGT...WITH NO
NOTABLE UPSTREAM SHORTWAVE DISTURBANCES APPARENT ATTM IN THE
SATELLITE IMAGERY OVER NRN MEX/NM. AT THE SAME TIME...POSITIVE-TILT
OF GRT BASIN TROUGH WILL KEEP MID-LVL LAPSE RATES RATHER MODEST.
NEVERTHELESS...WITH AMPLE MOISTURE ALREADY IN PLACE TO SUPPORT
STRONG STORMS AS FAR N AS SRN KS...AND WITH SUFFICIENT DEEP SHEAR
PRESENT FOR ORGANIZED/SUSTAINED STORMS...A LARGE PART OF THE S CNTRL
U.S. WILL HAVE TO BE MONITORED FOR POTENTIAL POCKETS OF
LOCALLY-ENHANCED STORM DEVELOPMENT LATER TODAY THROUGH EARLY WED.

...SRN/CNTRL PLNS TODAY THROUGH EARLY WED...
A SEASONABLY MOIST BOUNDARY LAYER ENVIRONMENT WILL PREVAIL ACROSS
THE SRN HALF OF THE PLNS AND INTO THE OZARKS THROUGH WED...S OF
STALLING SYNOPTIC-SCALE FRONT OVER NRN PARTS OF KS-MO. FARTHER S...A
SECONDARY FRONTAL ZONE/DIFFERENTIAL HEATING BOUNDARY SHOULD PERSIST
FROM NW TX ENE INTO NE OK/SW MO.

IN CONTRAST TO YESTERDAY...MID/UPR-LVL CLOUDS STREAMING NEWD FROM E
PACIFIC TROPICAL SYSTEM WILL SUPPRESS LOW-LVL DIURNAL
DESTABILIZATION/LAPSE RATE STEEPENING ALONG MUCH OF DRY LINE/LEE
TROUGH IN FAR ERN NM/W TX. COUPLED WITH THE DIFFUSE NATURE OF THAT
FEATURE...EML CAP...AND NEUTRAL /AT BEST/ LARGE-SCALE FORCING FOR
ASCENT...POTENTIAL FOR AFTN/EVE STORMS OVER THE REGION APPEARS
MINIMAL..ALTHOUGH NON-ZERO. STORMS MAY...HOWEVER...BECOME MORE
LIKELY OVER WRN AND NW TX AND PARTS OF THE TX PANHANDLE AFTER 06Z
WED AS HEIGHTS BEGIN TO FALL WITH THE APPROACH OF THE GRT BASIN
TROUGH. WHILE DIURNALLY-ENHANCED BOUNDARY LAYER CINH WILL LIMIT
LIKELIHOOD FOR SFC-BASED DEVELOPMENT...A CONDITIONAL RISK WILL EXIST
FOR A FEW STORMS WITH SVR HAIL AND POSSIBLY STRONG SFC WINDS GIVEN
40 TO PERHAPS 50 KT SWLY CLOUD-LAYER SHEAR. SOME OF THIS ACTIVITY
COULD SPREAD AS FAR E/NE AS S CNTRL OK/N CNTRL TX BY THE END OF THE
PERIOD.

MEANWHILE...FILTERED SUNSHINE WILL OCCUR TODAY ALONG AND S OF
DIFFERENTIAL HEATING BOUNDARY OVER PARTS OF NW TX AND SW THROUGH NE
OK. WHILE LOW-LVL UPLIFT ALONG THIS FEATURE WILL BE WEAK...IT IS NOT
ENTIRELY OUT OF THE QUESTION THAT A STORM OR TWO COULD ARISE ALONG
IT AND/OR ALONG TERRAIN-INDUCED CIRCULATIONS NEAR THE WICHITA MTNS
AND RED RVR. WERE SUCH DEVELOPMENT TO OCCUR...AVAILABILITY OF FAIRLY
RICH MOISTURE /PW AOA 1.25 IN/ AND 30-40 KT WSWLY DEEP SHEAR SUGGEST
A LOW CONDITIONAL RISK FOR SVR HAIL...LOCALLY DMGG WIND...AND/OR A
TORNADO.

FARTHER S...A SEPARATE AREA OF STRONG TO POSSIBLY SVR DIURNAL STORMS
MAY FORM OVER THE HIGHER TERRAIN OF SW TX...THE TX BIG BEND...AND
OVER THE MOUNTAINS OF N CNTRL MEXICO...WHERE RICH MOISTURE /PW AOA
1.50 INCHES/ WILL EXIST IN THE PRESENCE OF PERSISTENT LOW-LVL
UPSLOPE FLOW. WITH SUFFICIENT SHEAR ALSO PRESENT FOR STORM
ORGANIZATION/SUSTENANCE...THERE WILL BE A CONDITIONAL RISK FOR ISOLD
SVR HAIL/WIND FROM A POTENTIAL SUPERCELL OR TWO.

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