Feb 6, 2013 1300 UTC Day 1 Convective Outlook | |
Updated: Wed Feb 6 13:00:31 UTC 2013 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
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Probabilistic Tornado Graphic |
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
Probabilistic Damaging Wind Graphic |
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
Probabilistic Large Hail Graphic |
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
SPC AC 061256 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0656 AM CST WED FEB 06 2013 VALID 061300Z - 071200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... IN MID-UPPER LEVELS...SYNOPTIC PATTERN WILL FEATURE LOW AMPLITUDE FOR MOST OF PERIOD AND QUASI-ZONAL FLOW...WITH SEVERAL EMBEDDED SHORTWAVES IN NRN AND SRN STREAMS. MOISTURE CHANNEL IMAGERY...RAOBS...VWP PLOTS AND PROFILER DATA INDICATE ONE SHORTWAVE TROUGH LOCATED FROM TX SOUTH-PLAINS AND PERMIAN BASIN REGIONS SWD ACROSS NRN COAHUILA. NRN PORTION OF THIS FEATURE IS EXPECTED TO EJECT NEWD ACROSS NW TX...SERN OK AND AR TO WRN PORTIONS TN/KY BY 06Z...THEN ERN KY AT END OF PERIOD. SRN PORTION SHOULD MOVE MORE SLOWLY AND EWD...REACHING LA BY END OF PERIOD. MEANWHILE...PAC SHORTWAVE TROUGH WILL WEAKEN AS IT MOVES ESEWD FROM NV AND SRN CA ACROSS PORTIONS AZ/NM. AS THAT OCCURS...SEPARATE/SRN-STREAM PERTURBATION NOW OVER GULF OF CA WILL EJECT ENEWD ACROSS NRN MEX...REACHING TX BIG BEND REGION AROUND 00Z...AND CROSSING REMAINDER S TX OVERNIGHT. WEAK PERTURBATION NOW OVER NRN ROCKIES WILL AMPLIFY AND MOVE ESEWD ACROSS DAKOTAS TONIGHT. AT SFC...HIGH-PLAINS LEE TROUGHING SHOULD CONTINUE WITH SLGT EWD SHIFT...AS LOW NOW NEAR DEN MOVES/REDEVELOPS TO SERN CO BY 00Z...THEN SHIFTS SEWD ALONG FRONTOGENETIC ZONE TO WRN OK BY 12Z. AT THAT POINT...EXPECT COLD FRONT TO EXTEND SWWD FROM LOW ACROSS SERN NM. FRONT ALSO WILL EXTEND NEWD ACROSS ERN KS AND IA TO WEAK LOW OVER UPPER MS VALLEY...INDUCED BY NRN-STREAM/NRN-PLAINS SHORTWAVE TROUGH. FARTHER SE IN AND NEAR TSTM OUTLOOK...PATTERN HAS BEEN COMPLICATED ON MESOSCALE BY PRIOR OVERNIGHT CONVECTION. THAT ACTIVITY HAS LEFT OUTFLOW BOUNDARY FROM ABOUT 100 NM S GLS WSWWD ACROSS BAFFIN BAY REGION AND ZAPATA COUNTY TX. THIS BOUNDARY ALREADY APPEARS TO BE WEAKENING...BUT WILL BE REINFORCED AGAIN DURING DAY AS DIFFERENTIAL HEATING OCCURS S OF PERSISTENT TRAIN OF CLOUDS AND PRECIP NOW EVIDENT INVOF COT-GLS LINE. THIS BOUNDARY HAS MADE ORIGINAL MARINE FRONTAL ZONE SOMEWHAT ILL-DEFINED TO ITS N...HOWEVER THEY SHOULD MERGE OVER NWRN GULF. RESULTANT/REDEVELOPED MARINE FRONT IS EXPECTED TO REACH PORTIONS LA COAST BY END OF PERIOD...PERHAPS PENETRATING INLAND OVER SERN LA DEPENDING ON MODULATION OF BOUNDARY BY CONVECTION TO ITS N. ...S TX TO SRN LA... REF SPC MESOSCALE DISCUSSION 115 REGARDING NEAR-TERM/MRGL SVR THREAT OVER PORTIONS S TX. MRGL-PROBABILITY AREA WILL BE CHARACTERIZED THROUGH MOST OF PERIOD BY FAVORABLE DEEP-LAYER SHEAR...BUT WEAK LOW-LEVEL FORCING AND MODEST BUOYANCY LIMITED BY AREAS OF CLOUDS/PRECIP. AREAS OF STG/ISOLATED SVR TSTMS MAY OCCUR IN ANY OF AT LEAST THREE MOST-PROBABLE SCENARIOS THROUGH PERIOD... 1. SRN PORTION OF EXISTING PRECIP PLUME...CONTAINING SCATTERED TO WIDELY SCATTERED TSTMS...MAY BUILD SWD AS OUTFLOW/DIFFERENTIAL-HEATING BOUNDARY DRIFTS NWD AND TIGHTENS SOMEWHAT. ALSO...12Z CRP RAOB SHOWS SFC-BASED EFFECTIVE LIFTED PARCEL N OF OUTFLOW BOUNDARY WITH UPPER 60S SFC TEMP. AS SUCH...SFC-BASED PARCELS MAY BECOME AVAILABLE TO SOME OF THIS ACTIVITY...IN TURN SUPPORTING POTENTIAL FOR ISOLATED DAMAGING GUSTS AS WELL AS LARGE HAIL. HODOGRAPHS ALONG BOUNDARY WILL BE ENHANCED SOMEWHAT BY BACKING OF SFC WINDS...THOUGH THOSE WINDS SHOULD REMAIN RATHER WEAK. THIS ALONG WITH 40-50 KT EFFECTIVE SHEAR MAGNITUDES WILL SUPPORT POTENTIAL ORGANIZATION OF ANY CELLS THAT CAN INTERACT WITH BOUNDARY EITHER IN THIS OR NEXT REGIME. ALSO...SINCE ISOLATED HAIL CANNOT BE RULED OUT N OF BOUNDARY...MRGL SVR PROBABILITIES ARE KEPT ALONG MID-UPPER TX COAST. 2. ANY TSTMS DEVELOPING IN WARM SECTOR...ESPECIALLY IF INTERACTING WITH BOUNDARY OVER DEEP S TX...ALSO MAY POSE AT LEAST ISOLATED SVR THREAT. HOWEVER...BOUNDARY-LAYER FORCING FOR ASCENT IN WARM SECTOR APPEARS VERY WEAK AND UNCERTAIN...AND SUCH DEVELOPMENT MAY NOT OCCUR AT ALL. 3. COASTAL SRN/SERN LA...DURING LATE/OVERNIGHT PERIOD...APPEARS CONDITIONALLY TO BE GREATEST THREAT POTENTIALLY REQUIRING OUTLOOK UPGRADE. ANTECEDENT CONVECTION MAY ABATE ENOUGH TO ALLOW BOUNDARY INLAND AND...IN TURN...PERMIT CONVECTION TO ACCESS SFC-BASED PARCELS. FCST HODOGRAPHS ALONG MARINE FRONT ARE RATHER LARGE--WITH 0-1 KM AGL SRH 300-500 J/KG AND 55-65 KT EFFECTIVE SHEAR EVIDENT BENEATH SIMILAR 500-MB WIND SPEEDS. ANY SFC-BASED TSTMS INTERACTING WITH THIS SORT OF ENVIRONMENT WILL POSE TORNADO AND DAMAGING-GUST THREAT...BUT POTENTIAL REMAINS TOO CONDITIONAL TO BOOST PROBABILITIES TO CATEGORICAL THRESHOLDS ATTM. ..EDWARDS/MOSIER.. 02/06/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z