Mar 16, 2006 0600 UTC Day 1 Convective Outlook Updated: Thu Mar 16 05:52:12 UTC 2006 Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
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SPC AC 160550 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1150 PM CST WED MAR 15 2006 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS W-CENTRAL/SW TX...S-CENTRAL/SE TX TO EXTREME W-CENTRAL/SWRN MS... ...SYNOPSIS... MID/UPPER LEVEL SYNOPTIC PATTERN WILL FEATURE SLOWLY AMPLIFYING RIDGE FROM S-CENTRAL TX ACROSS WRN DAKOTAS THROUGH PERIOD...IN WAKE OF SHORTWAVE TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL HIGH PLAINS. THIS TROUGH IS FCST TO DEAMPLIFY AS IT MOVES SEWD INTO CONFLUENT FLOW ASSOCIATED WITH ERN CANADA UPPER VORTEX. ASSOCIATED SFC CYCLONE -- ANALYZED ATTM OVER SERN NEB -- SHOULD MOVE ESEWD ALONG PRE-EXISTING BAROCLINIC ZONE TOWARD NC BY 17/12Z. ASSOCIATED SFC COLD FRONT WILL PLUNGE SWD/SEWD ACROSS SRN PLAINS AND LOWER MS VALLEY...DECELERATING AND BECOMING MORE SHALLOW OVER SRN HIGH PLAINS AND LOWER PECOS VALLEY REGION BY END OF PERIOD. LONG-LASTING EPISODE OF WLY/SWLY FLOW ALOFT WILL CONTRIBUTE TO LEE-SIDE HEIGHT FALLS IN LOW LEVELS OVER SW TX AND NM. THIS WILL MAINTAIN VIGOROUS LOW LEVEL RETURN FLOW AND MOISTENING ABOVE FRONTAL SFC. ...LOWER MS VALLEY TO S-CENTRAL TX... BAND OF TSTMS MAY DEVELOP DURING AFTERNOON INVOF COLD FRONT BETWEEN LOWER MS VALLEY AND SRN HILL COUNTRY OF S-CENTRAL/SW TX. DAMAGING DOWNDRAFTS AND LARGE HAIL WILL BE POSSIBLE. ALTHOUGH LOW LEVEL FLOW SHOULD REMAIN WEAK ALONG/AHEAD OF SFC FRONT -- LIMITING HODOGRAPH SIZE -- VEERING WIND PROFILES IN BOUNDARY LAYER AND 35-45 KT MIDLEVEL FLOW WILL CONTRIBUTE TO 40-50 KT 0-6 KM SHEAR...SUPPORTING BLEND OF ORGANIZED MULTICELL...LINEAR AND MRGL SUPERCELL MODES TO TSTMS OVER AREA. PLUME OF MID/UPPER 60S F SFC DEW POINTS NOW IS EVIDENT OVER DEEP S TX...NERN MEX AND ADJACENT PORTION S WRN GULF. MOIST SECTOR SHOULD BROADEN SOMEWHAT AND LIFT NWD THROUGH EARLY-MIDDLE PART OF PERIOD...ENCOUNTERING FRONTAL ZONE OVER OUTLOOK AREA. BULK OF SFC-BASED CONVECTION SHOULD DEVELOP FROM MID/LATE AFTERNOON THROUGH EARLY EVENING. ...NOCTURNAL -- S-CENTRAL/SW TX... STRONG LOW LEVEL WAA AND MOIST ADVECTION REGIME WILL CONTINUE ALL NIGHT ACROSS THIS REGION...ALONG AND N OF SFC FRONTAL ZONE. COVERAGE AND INTENSITY OF CONVECTION SHOULD INCREASE AFTER DARK...AND PROGRESSIVELY THROUGH END OF PERIOD...AS MORE PARCELS ARE RAISED ISENTROPICALLY TO LFC. OUTSIDE CONVECTIVE CLUSTERS...ELEVATED MUCAPES MAY EXCEED 1000 J/KG IN SOME LOCALES AROUND PERMIAN BASIN OR SOUTH-PLAINS REGION OF W TX...GENERALLY DIMINISHING WITH NWD EXTENT. EVEN WHEN TRUNCATING RELATIVELY STABLE/LOW-THETAE BOUNDARY LAYER N OF FRONT FROM KINEMATIC PROFILE...VERTICAL SHEAR WILL FAVOR SOME ORGANIZED SEVERE POTENTIAL. FCST SOUNDINGS SUGGEST UP TO 50 KT EFFECTIVE BULK SHEAR THROUGH LOWEST HALF OF STORM DEPTH...INDICATING SUFFICIENT PROBABILITIES FOR ELEVATED SUPERCELLS AND LARGE HAIL TO INCLUDE WITHIN CATEGORICAL SLGT RISK LINE. ...SRN/ERN NM... PEAK DIABATIC HEATING IN MID/LATE AFTERNOON...COMBINED WITH MRGL BOUNDARY LAYER MOISTURE...SHOULD CONTRIBUTE TO HIGH-BASED TSTM INITIATION OVER BORDERLANDS REGION OF SRN NM AND FAR W TX. STRONG GUSTS AND ISOLATED HAIL MAY OCCUR FROM MOST VIGOROUS CONVECTION. EXPECT FAVORABLY STEEP LOW-MIDLEVEL LAPSE RATES -- EXCEEDING 8 DEG C/KM ON AVERAGE FROM SFC-500 MB -- LEADING TO MLCAPES UP TO ABOUT 300 J/KG IN MODIFIED ETA/ETA-KF FCST SOUNDINGS IN S-CENTRAL/SWRN NM LATE AFTERNOON. CONVERGENT BOUNDARY LAYER PROFILE SHOULD DEVELOP OVER REGION...WITH SELY POST-FRONTAL FLOW OVER SERN NM AND SWLY WINDS ACROSS SWRN NM AND AZ CONTRIBUTING TO ADDITIONAL LOW LEVEL ASCENT. 35-45 KT DEEP-LAYER SHEAR PROFILES ARE EXPECTED. ORGANIZED SEVERE POTENTIAL WILL BE LIMITED BY LACK OF MORE ROBUST LOW LEVEL MOISTURE AND ASSOCIATED MITIGATION OF BUOYANCY. THIS REGIME SHOULD EVOLVE INTO ELEVATED HAIL THREAT WITH EWD EXTENT AND WITH TIME ACROSS SRN AND ERN NM DURING EVENING/OVERNIGHT HOURS...TRANSITIONING INTO NWRN PORTION OF ELEVATED RETURN FLOW AIR MASS DISCUSSED ABOVE. ..EDWARDS/JEWELL.. 03/16/2006 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |