DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 301255
SWODY1
SPC AC 301253

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0753 AM CDT WED OCT 30 2013

VALID 301300Z - 311200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS LOWER MO VALLEY ACROSS
CENTRAL/SRN PLAINS TO SW TX...

...SYNOPSIS...
MAIN UPPER-AIR FACTOR FOR THIS PERIOD AND BEYOND WILL BE
HIGH-AMPLITUDE SYNOPTIC TROUGH -- NOW MANIFEST AS NNE-SSW-ELONGATED
CYCLONE COVERING MUCH OF GREAT BASIN AND CENTRAL/NRN ROCKIES
REGIONS. THIS FEATURE IS FCST TO EVOLVE INTO MORE
PROGRESSIVE/OPEN-WAVE BUT STILL HIGHLY AMPLIFIED TROUGH THROUGH
PERIOD. STG BASAL SHORTWAVE TROUGH -- EVIDENT IN MOISTURE CHANNEL
IMAGERY OVER LAS REGION -- IS FCST TO PIVOT EWD ACROSS AZ
TODAY...REACHING SWRN CO...NWRN NM AND SERN AZ BY 00Z...THEN
STRENGTHENING AND ACCELERATING EWD TO SRN HIGH PLAINS BY END OF
PERIOD. MEANWHILE...COPIOUS MID-UPPER LEVEL MOISTURE CONTINUES TO
STREAM NEWD OFF WHAT IS NOW NERN PAC T.D. RAYMOND...OVER NRN MEX AND
MUCH OF TX/OK/AR/LA.

AT SFC...STG/INITIALLY QUASISTATIONARY FRONTAL ZONE EXTENDED FROM
LOW OVER NERN KS/NWRN MO REGION SWWD ACROSS S-CENTRAL KS AND NWRN OK
TO NRN TX PANHANDLE...TO ANOTHER LOW OVER SERN CO. PAC COLD FRONT
WAS EVIDENT FROM THAT LOW SWWD ACROSS CENTRAL/SRN NM. LATTER FRONT
WILL MOVE EWD ONLY SLOWLY AT FIRST...THEN BECOME BETTER-DEFINED WITH
TIME THIS EVENING AND OVERNIGHT...OVERTAKING DRYLINE FROM N-S ACROSS
SRN HIGH PLAINS. BY 12Z...FRONTAL-WAVE LOW SHOULD EVOLVE OVER NRN
OK...WITH COLD FRONT SWWD ACROSS W TX.

...CENTRAL/SRN PLAINS...LOWER MO VALLEY...
SE-NW ALIGNED BELT OF SCATTERED TSTMS...WITH ISOLATED SVR HAIL CORES
POTENTIALLY EMBEDDED WITHIN...IS MOVING NEWD ACROSS ERN NEB AND
LOWER MO VALLEY REGION. THIS ACTIVITY IS FOLLOWED BY ADDITIONAL
ELEVATED CONVECTION INCREASING IN COVERAGE/INTENSITY AS IT MOVES
NEWD OUT OF PORTIONS CENTRAL KS...ALSO N OF SFC FRONT. REF SPC
MESOSCALE DISCUSSION 1980 FOR NEAR-TERM DETAILS.

OTHERWISE...THREE RELATIVE CONCENTRATIONS OF POTENTIAL NOW ARE
APPARENT WITHIN WHAT OTHERWISE APPEARS AS POORLY
FOCUSED...CONVECTIVELY MESSY AND VERY BROAD SVR RISK AREA.

1. CORRIDOR FROM CENTRAL/SE TX INTO OK THROUGH AFTN...
THIS REGIME WILL REMAIN ASSOCIATED WITH BROAD LLJ AND RELATED
WAA/MOISTURE-TRANSPORT PROCESS...CHARACTERIZED BY WEAK INSTABILITY
BUT FAVORABLE LOW-LEVEL HODOGRAPHS AND GRADUALLY INTENSIFYING DEEP
SHEAR. EPISODES OF WIDELY SCATTERED TO SCATTERED NON-SVR TSTMS IN
CLUSTERS ALREADY HAVE BEEN OCCURRING FOR SEVERAL HOURS OVER THIS
AREA...INCREASING OVERALL IN COVERAGE. MORE DEVELOPMENT IS LIKELY
THROUGHOUT TODAY ON ITS WRN FRINGES AS
A. LLJ REPLENISHES LOW-LEVEL THETAE AWAY FROM PERSISTENT CONVECTIVE
OVERTURNING AND
B. DESPITE ABUNDANT CLOUD COVER...DIFFUSE DIABATIC HEATING YIELDS
STEADILY INCREASING SFC-BASED BUOYANCY THROUGH LATE AFTN.

2. EVENING/OVERNIGHT CONVECTIVE CORRIDOR FROM SW TX TO SRN OK...
DEEP-LAYER LIFT AND SHEAR EACH WILL INCREASE...IN ENVIRONMENT
CHARACTERIZED BY RICH LOW-LEVEL MOISTURE WITH SFC DEW POINTS
COMMONLY UPPER 60S TO LOW 70S F. THIS PROCESS SHOULD HELP TO
MAINTAIN SFC-BASED EFFECTIVE INFLOW PARCELS WITH WEAK CINH...BENEATH
STEEP MIDLEVEL LAPSE RATES...IN SUPPORT OF MOSTLY CLUSTERED TO
QUASI-LINEAR CONVECTION. THOUGH UPPER-LEVEL LAPSE RATES MAY BE
MITIGATED SOMEWHAT IN PLUME OF MOISTURE FROM RAYMOND...MLCAPE/MUCAPE
IN 1500-2000 J/KG MAY BE ATTAINABLE AWAY FROM PERSISTENT/ANTECEDENT
CONVECTIVE AREAS. LLJ WILL KEEP 0-1 KM SHEAR VALUES AND HODOGRAPH
LARGE...THOUGH WEAKNESSES ABOVE THAT MAY LIMIT TOTAL LOW-LEVEL
SHEAR. STILL...CONDITIONAL TORNADO RISK IS EVIDENT ON TOP OF
WIND/HAIL THREAT...DEPENDENT LARGELY ON MAINTENANCE OF ANY EMBEDDED
OR DISCRETE SUPERCELL MODES THAT CAN DEVELOP.

3. PORTIONS SRN KS...WRN OK AND W TX TONIGHT...
AS AFOREMENTIONED SHORTWAVE TROUGH APCHS SRN HIGH
PLAINS...HEIGHT/THERMAL GRADIENTS ALOFT WILL TIGHTEN CONSIDERABLY
AND ADVANCE EWD AMIDST PRONOUNCED DCVA AND STG HEIGHT FALLS.
RIGHT-ENTRANCE REGION OF AOA 140-KT 250-MB JET STREAK WILL BE
PRESENT OVER THIS REGION...ALONG WITH LOW-LEVEL FRONTOGENETIC
FORCING. THESE PROCESSES WILL RESULT IN INCREASING DEEP SHEAR...
LAPSE RATES AND LIFT OVER WRN FRINGES OF WARM/MOIST SECTOR AFTER
DARK. BAND OF SCATTERED TO LOCALLY NUMEROUS TSTMS MAY
FORM...OFFERING SVR HAIL...OCNL DAMAGING GUSTS AND LOW BUT NONZERO
TORNADO RISK.

WHILE THOSE REGIMES REPRESENT MOST PROBABLE SOURCES OF ORGANIZED SVR
CONVECTION...PLEASE BEAR IN MIND THAT STRENGTHENING WINDS ALOFT WILL
SPREAD OVER SEASONALLY MOIST AND AT LEAST MRGLLY UNSTABLE WARM/MOIST
SECTOR ALL PERIOD LONG. AS SUCH...AT LEAST ISOLATED SVR OF ANY TYPE
CAN OCCUR IN BETWEEN...ANYWHERE OVER OUTLOOK AREA...THROUGHOUT TODAY
AND TONIGHT.

..EDWARDS/COHEN.. 10/30/2013

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