Apr 21, 2014 1630 UTC Day 1 Convective Outlook | |||||||||
Updated: Mon Apr 21 16:31:39 UTC 2014 ( | ) | |||||||||
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. |
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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. |
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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. |
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SPC AC 211628 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1128 AM CDT MON APR 21 2014 VALID 211630Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN OK AND THE ARKLATEX SWWD INTO CNTRL TX... ...SUMMARY... ISOLATED SEVERE STORMS MAY DEVELOP FROM PARTS OF THE ARKLATEX REGION TO SOUTH-CENTRAL TEXAS THIS AFTERNOON AND EVENING. ...SYNOPSIS... PATTERN WILL BECOME SOMEWHAT MORE AMPLIFIED THIS PERIOD AS HEIGHTS RISE OVER THE RCKYS...DOWNSTREAM FROM FAIRLY POTENT/PROGRESSIVE UPR LOW/TROUGH APPROACHING THE PACIFIC NW. AS THIS OCCURS...THE LAST IN A SERIES OF IMPULSES COMPRISING THE SRN PLNS SRN BRANCH TROUGH WILL TRACK FROM CNTRL OK/N CNTRL TX ESE TO THE ARKLATEX THIS EVE...AND INTO THE LWR MS VLY EARLY TUE. THE FEATURE SHOULD GRADUALLY WEAKEN AS IT BECOMES ABSORBED WITHIN AMPLIFYING NRN STREAM TROUGH NOW OVER THE UPR MS VLY/UPR GRT LKS. FLOW WILL REMAIN WEAK AT THE SFC. THE MAIN FEATURES OF NOTE AFFECTING TSTM DEVELOPMENT WILL BE /1/ W-E OUTFLOW BOUNDARY NEAR THE RED RVR AND /2/ SW-NE LEE TROUGH/DRY LINE IN CNTRL TX. THE OUTFLOW BOUNDARY SHOULD REMAIN NEARLY STNRY TODAY WHILE THE TROUGH ADVANCES SE AND IS OVERTAKEN BY WEAK UPSTREAM COLD FRONT NOW OVER NW TX. SCTD TSTMS EXPECTED TO FORM ALONG THE OUTFLOW BOUNDARY...AND TO A LESSER EXTENT ALONG THE LEE TROUGH/DRY LINE...MAY POSE A RISK FOR HAIL AND LOCALLY DMGG WIND FROM SRN OK AND THE ARKLATEX SWWD INTO CNTRL TX THIS AFTN AND EVE. ...ARKLATEX/SRN OK SW INTO CNTRL TX... TSTMS SHOULD FORM ALONG STALLED OUTFLOW BOUNDARY NEAR THE RED RVR THIS AFTN IN RESPONSE TO SFC HEATING...MAXIMIZED SFC CONVERGENCE...AND THE CONTINUED ESEWD ADVANCE OF OK UPR IMPULSE. LATER IN THE DAY...MORE SCTD DEVELOPMENT SHOULD OCCUR SWWD IN ZONE OF WEAKER CONVERGENCE ALONG DRY LINE/LEE TROUGH. WHILE BUOYANCY WILL NOT BE EXTREME /AFTN MLCAPE EXPECTED TO RANGE FROM AROUND 500 J/KG IN SRN OK TO ABOVE 1500 J/KG IN CNTRL TX/...IT WILL BE SUFFICIENT FOR STRONG UPDRAFTS CAPABLE OF SVR HAIL GIVEN RELATIVELY COOL MID-LVL TEMPERATURES WITH UPR TROUGH. AND...WHILE THE MID-TROPOSPHERIC FLOW WILL REMAIN COMPARATIVELY MODEST AS THE UPR IMPULSE WEAKENS...30-35 KT WNWLY DEEP SHEAR SHOULD FOSTER SOME UPDRAFT ORGANIZATION/SUSTENANCE. THE OVERALL SETUP APPEARS MOST FAVORABLE FOR STRONG MULTICELLS THAT...ESPECIALLY ALONG THE OUTFLOW BOUNDARY...SHOULD MERGE INTO ESE TO SE-MOVING CLUSTERS WITH HAIL AND EMBEDDED SMALL BOWING SEGMENTS WITH LOCALLY DMGG WIND OVER N CNTRL/NE TX. THE STORMS MAY REMAIN SOMEWHAT MORE DISCRETE SWWD ALONG TROUGH/DRY LINE...WHERE ONE OR TWO COULD EXHIBIT TRANSIENT SUPERCELL CHARACTERISTICS. MOST OF THE ACTIVITY SHOULD DIMINISH FAIRLY QUICKLY AFTER SUNSET. ..CORFIDI/JEWELL.. 04/21/2014 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z |