Aug 4, 2011 0100 UTC Day 1 Convective Outlook | |
Updated: Thu Aug 4 00:58:08 UTC 2011 | |
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 040053 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0753 PM CDT WED AUG 03 2011 VALID 040100Z - 041200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... MIDDLE-UPPER LEVEL PATTERN REMAINS CHARACTERIZED BY INTENSE ANTICYCLONE CENTERED OVER ARKLATEX REGION...WITH TROUGHING ALONG E AND W COASTS. IN BETWEEN...SEVERAL RELATIVELY LOW-AMPLITUDE SHORTWAVES PREVAIL. THIS INCLUDES WEAK PERTURBATIONS NOW EVIDENT IN MOISTURE CHANNEL IMAGERY MOVING SEWD ACROSS SRN IL...AND NEWD OVER UT. VIS AND COMPOSITE REFLECTIVITY ANIMATIONS INDICATE MCV DRIFTING NEWD ACROSS SERN NEB. AT SFC...23Z ANALYSIS SHOWED LOW OVER CENTRAL/NERN PA...WARM FRONT SWD OVER ERN VA THEN EWD OFFSHORE HAMPTON ROADS REGION...AND COLD FRONT SWWD ACROSS ERN KY TO NRN AR AND NERN OK. FRONT EFFECTIVELY HAS BEEN SHUNTED FARTHER S THAN SYNOPTIC POSITION ACROSS CENTRAL/SRN OK BECAUSE OF AGGREGATE OUTFLOW. FRONTAL ZONE GENERALLY W OF MS RIVER SHOULD BECOME QUASISTATIONARY THROUGH REMAINDER PERIOD...WHILE DRIFTING SEWD ACROSS TN VALLEY REGION AND CENTRAL/SRN APPALACHIANS. ...CENTRAL/SRN PLAINS TO SRN APPALACHIANS... WIDELY SCATTERED TO SCATTERED TSTMS REMAIN OVERALL...WITH SOMEWHAT MORE DENSE MESOSCALE CONCENTRATION OVER PORTIONS KS/OK. PRE-STORM/BOUNDARY-LAYER AIR MASS ACROSS THIS REGION TRANSITIONS FROM HIGH-PW/LARGE-CAPE REGIME OVER KY/TN TO DEEPLY MIXED AND STRONGLY HEATED CHARACTER OVER SRN/CENTRAL PLAINS...EACH SUPPORTING LOCALLY STG-SVR DOWNDRAFTS IN REGIME OF WEAK DEEP-TROPOSPHERIC FLOW/SHEAR. CONVECTIVE COVERAGE/INTENSITY GENERALLY SHOULD LESSEN THROUGH REMAINDER EVENING...DUE STABILIZING EFFECTS OF BOTH DIABATIC SFC COOLING AND INCREASING COVERAGE OF OUTFLOW AIR. ...WRN PORTIONS SD/NEB... WIDELY SCATTERED TO SCATTERED TSTMS ARE EVIDENT IN BAND FROM NEAR I-90 IN WRN SD SSWWD ACROSS CENTRAL/NRN NEB PANHANDLE AND ADJACENT PORTIONS EXTREME ERN WY. SD ACTIVITY HAS PRODUCED CONSIDERABLE OUTFLOW ALREADY...WITH LOOSELY ORGANIZED COLD POOL EVIDENT OVER BADLANDS REGION OF SD AND MORE ISOLATED/LOCALIZED DOWNDRAFT THREAT FARTHER S AND SW. RELATIVELY NARROW SPATIAL/TEMPORAL CORRIDOR REMAINS THROUGH WHICH STG/DAMAGING GUSTS ARE POSSIBLE FOR ANOTHER FEW HOURS. MODIFIED RAOBS AND RUC SOUNDINGS SUGGEST THAT CURRENTLY OBSERVED SFC THETAE DECREASES WITH EWD EXTENT...COMBINED WITH SFC DIABATIC COOLING...WILL REDUCE GUST THREAT WITH TIME THIS EVENING. ...AZ... ISOLATED TO WIDELY SCATTERED TSTMS SHOULD PERSIST FOR ANOTHER FEW HOURS ACROSS THIS REGION...AMIDST PRE-STORM SFC TEMPS UPPER 90S TO LOW 100S F AND DEW POINTS 50S OVER LOWER ELEVATIONS. 00Z TUS RAOB AND MODIFIED MODEL SOUNDINGS EACH INDICATE POTENTIAL FOR ISOLATED STG-SVR GUSTS WITH MOST INTENSE DOWNDRAFTS...GIVEN DEEP/WELL-MIXED SUB CLOUD LAYERS AND POTENTIAL FOR EVAPORATIVE COOLING/ACCELERATION ON STORM SCALE. ..EDWARDS.. 08/04/2011 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z