SPC AC 051935
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0235 PM CDT MON OCT 05 2009
VALID 052000Z - 061200Z
...NO SVR TSTM AREAS FORECAST...
...20Z UPDATE...
ALTHOUGH LOW-LEVEL MOISTURE RETURN IS ONGOING NEAR THE LEE SURFACE
TROUGH ACROSS THE CENTRAL/SOUTHERN HIGH PLAINS...RELATIVELY WARM
LOWER/MID TROPOSPHERIC TEMPERATURES AND WEAK MID-LEVEL LAPSE RATES
ARE MINIMIZING CONVECTIVE POTENTIAL. THIS GENERALLY STILL APPEARS
LIKELY TO REMAIN THE CASE THROUGH THE REMAINDER OF THE FORECAST
PERIOD. HOWEVER...AS THE MID-LEVEL CLOSED LOW CONTINUES TO LIFT OUT
OF THE SPLITTING LARGER SCALE TROUGH OVER THE WESTERN STATES...IT IS
NOT COMPLETELY OUT OF THE QUESTION THAT MID-LEVEL COOLING COULD
SUFFICIENTLY STEEPEN LAPSE RATES FOR AT LEAST A MARGINAL OR HIGHLY
LOCALIZED SEVERE THREAT NEAR THE DEVELOPING CENTRAL PLAINS CYCLONE.
OTHERWISE...LATEST RUC GUIDANCE SUGGESTS MODERATE TO STRONG
POTENTIAL INSTABILITY HAS DEVELOPED WITHIN THE VERY MOIST
ENVIRONMENT ACROSS THE TEXAS COASTAL PLAIN AND DEEP SOUTH TEXAS INTO
THE PECOS VALLEY. LARGE-SCALE FORCING FOR CONVECTIVE DEVELOPMENT
REMAINS WEAK/UNCLEAR ACROSS THIS REGION...BUT SOMEWHAT WEAKER
CAPPING AND MORE FAVORABLE OROGRAPHIC FORCING ACROSS THE PECOS/RIO
GRANDE VALLEYS SEEM TO OFFER THE BEST POTENTIAL FOR THE INITIATION
OF AN ISOLATED LATE AFTERNOON/EARLY EVENING STORM OR TWO.
..KERR/COOK.. 10/05/2009
.PREV DISCUSSION... /ISSUED 1113 AM CDT MON OCT 05 2009/
...W TX INTO THE OK/SERN KS...
MID MORNING SURFACE ANALYSES INDICATE SURFACE FRONT REMAINING
STALLED E-W FROM THE UPPER TX COAST INTO THE RIO GRANDE VALLEY
BETWEEN LRD AND DRT...WITH 'SOUPY' GULF AIR CHARACTERIZED BY NEAR
80F DEWPOINTS TRAPPED TO ITS SOUTH. LEE TROUGH IS ALREADY BECOMING
DEFINED SOUTH OF A LOW CENTER ACROSS ERN CO AND ALONG THE TX-NM
BORDER...WHICH IS EXPECTED TO MIX EWD THROUGH THE DAY AS ROBUST
HEATING OCCURS ACROSS NM INTO THE SRN HIGH PLAINS. SHEAR ALOFT WILL
STRENGTHEN THROUGH THE PERIOD AS LEADING MID LEVEL IMPULSE AND
ASSOCIATED JET OVERSPREAD THE SRN/CENTRAL HIGH PLAINS AHEAD OF
SECONDARY UPPER LOW DIGGING SSWWD ACROSS CA. ALTHOUGH INFLUX OF
INCREASING LOW LEVEL MOISTURE WILL CONTINUE TODAY INTO WRN TX AND
WILL OVERSPREAD MUCH OF THE SRN PLAINS LATER TONIGHT...PRIMARY
NEGATIVE FOR TSTM DEVELOPMENT INVOF THE LEE TROUGH WILL BE CAPPING
AND LIMITED ASCENT OVER THE SRN HIGH PLAINS. HOWEVER...INFLUX OF
MID/UPPER 60S SFC DEW POINTS AND LONG HODOGRAPHS SUGGEST
LOW/CONDITIONAL PROBABILITIES OF SEVERE TSTM DEVELOPMENT REMAIN
WARRANTED. FARTHER NE...INCREASING ASCENT ASSOCIATED WITH
STRENGTHENING LOW LEVEL WAA OVERNIGHT SHOULD SUPPORT
SCATTERED...ELEVATED TSTM DEVELOPMENT FROM PORTIONS OF WRN/NRN TX
INTO THE OZARK REGION LATE IN THE PERIOD. EFFECTIVE SHEAR AROUND
40-50 KT AND MUCAPE IN EXCESS OF 1000 J/KG SHOULD SUPPORT A FEW MORE
ROBUST/PERSISTENT STORMS WITH ATTENDANT THREAT OF MARGINALLY SEVERE
HAIL...ALTHOUGH THREAT SHOULD DIMINISH WITH NEWD EXTENT INTO MO
GIVEN WEAKER INSTABILITY.
...CENTRAL HIGH PLAINS...
STRENGTHENING ASCENT AND DEVELOPMENT OF MARGINAL SURFACE-BASED
INSTABILITY THIS AFTERNOON MAY ALLOW A FEW STORMS TO DEVELOP AND
ROOT INTO THE BOUNDARY LAYER OVER NERN CO/NERN KS/SWRN NEB LATER
THIS AFTERNOON/EVENING. ALTHOUGH INSTABILITY REMAINS MEAGER...DEEP
ASCENT AND STRONG LOW-DEEP LAYER SHEAR SHOULD SUPPORT AT LEAST A LOW
PROBABILITY OF SEVERE TSTMS...INCLUDING LOW-TOPPED SUPERCELLS/LINES.
ACTIVITY MAY BE BRIEF-LIVED AS STRONG SURFACE COLD FRONT WILL TEND
TO UNDERCUT THE ACTIVITY...HOWEVER ISOLATED HAIL AND EVEN A BRIEF
TORNADO CAN NOT BE RULED OUT.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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