May 30, 2014 2000 UTC Day 1 Convective Outlook | |||||||||
Updated: Fri May 30 19:59:37 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 301956 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0256 PM CDT FRI MAY 30 2014 VALID 302000Z - 311200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN CO INTO WRN NEB AND CNTRL SD... ...SUMMARY... A FEW SEVERE THUNDERSTORMS WILL BE POSSIBLE FROM NORTHEASTERN COLORADO INTO NORTH DAKOTA...WITH MORE ISOLATED ACTIVITY ACROSS THE CAROLINAS AND SOUTHWEST VIRGINIA...FLORIDA...AND THE CENTRAL GULF COAST. ...NERN CO INTO WRN NEB...SD AND ND... ISOLATED SEVERE STORMS CAPABLE OF LARGE HAIL CONTINUE TO EVOLVE ACROSS WRN NEB THIS AFTERNOON...WITH OTHER ACTIVITY INTO NERN CO. SATELLITE IMAGERY SHOWS A WEAK UPPER DISTURBANCE MOVING NEWD ACROSS SRN CO...AND THIS MAY SUPPORT FURTHER DEVELOPMENT THIS AFTERNOON. WEAKLY VEERING WIND PROFILES WITH HEIGHT...AMPLE MOISTURE AND SUFFICIENT LAPSE RATES WILL FAVOR SEVERE HAIL...BUT WEAK SHEAR ALSO SUGGESTS MULTICELLULAR CONVECTION WILL BE POSSIBLE WHICH WOULD FAVOR OUTFLOW WINDS. FARTHER N...HEATING PERSISTS FROM SD INTO ERN ND AND NWRN MN NEAR THE INVERTED SURFACE TROUGH. ISOLATED SEVERE STORMS WITH MAINLY A HAIL THREAT CONTINUE TO BE POSSIBLE IN THESE AREAS DRIVEN MAINLY BY INSTABILITY. ...ARKLAMISS INTO AL... AREAS OF VIGOROUS CONVECTION CONTINUE TO PROPAGATE IN A GENERALLY NWD DIRECTION. GIVEN FAVORABLE TIME OF DAY...AMPLE MOISTURE AND AREAS OF HEATING...A WET MICROBURST CANNOT BE RULED OUT. ...ERN NY INTO NEW ENGLAND... SCATTERED LOW-TOPPED THUNDERSTORMS CONTINUE TO EVOLVE SWD IN ADVANCE OF A WEAK UPPER LOW ACROSS ERN NY INTO NEW ENGLAND WHERE HEATING HAS LED TO WEAK DESTABILIZATION. WITH LOW DEWPOINTS AND WEAK SHEAR...THE ENVIRONMENT WILL CONTINUE TO FAVOR SMALL NON-SEVERE HAIL. ..JEWELL.. 05/30/2014 .PREV DISCUSSION... /ISSUED 1133 AM CDT FRI MAY 30 2014/ ...CENTRAL HIGH PLAINS INTO THE NRN PLAINS... SOUTHWEST FLOW ALOFT IS FORECAST TO PERSIST ACROSS THE NRN ROCKIES INTO THE NRN PLAINS AS A HIGH AMPLITUDE BLOCKING PATTERN CONTINUES. WATER VAPOR IMAGERY INDICATES AN EMBEDDDED SHORT WAVE TROUGH LIFTING NEWD ACROSS NWRN CO AND CENTRAL WY TOWARD THE NRN PLAINS ALONG THE WRN EDGE OF A DEEP MOISTURE PLUME EXTENDING FROM CO INTO ND. 12Z SOUNDINGS AND SATELLITE DATA EXHIBIT PW VALUES AROUND 1 IN WITHIN THIS PLUME WITH MODEL GUIDANCE FORECASTING A SLOW INCREASE IN TOTAL MOISTURE INTO TONIGHT. ASSOCIATED WIDESPREAD CLOUD COVER AND ISOLATED CONVECTION ARE EVIDENT AT THIS TIME...ALTHOUGH VISIBLE IMAGERY SUGGESTS STRONGER DIABATIC HEATING AND DESTABILIZATION WILL OCCUR ALONG THE ERN EDGE OF THE CLOUD BAND FROM NERN CO INTO CENTRAL SD THIS AFTERNOON. GIVEN SURFACE DEW POINTS IN THE MID 50S TO LOWER 60S...THE HEATING WILL CONTRIBUTE TO MLCAPE OF 1000-1500 J/KG LATER THIS AFTERNOON AND EVENING. MODEL GUIDANCE INDICATES ADDITIONAL STORMS WILL DEVELOP THIS AFTERNOON WITHIN A WEAKLY CAPPED ENVIRONMENT FROM NERN CO/SERN WY NEWD INTO THE DAKOTAS NEAR A SLOW MOVING SW/NE ORIENTED SURFACE FRONT. STRONGER SWLY WINDS ALOFT ARE LOCATED GENERALLY ALONG/WEST OF THE FRONT WHERE DEEP LAYER SHEAR OF 30-40 KT IS FORECAST. THIS WILL PROMOTE POTENTIAL FOR A FEW ORGANIZED STORMS/WEAK SUPERCELLS TO DEVELOP NEAR AND IMMEDIATELY WEST OF THE SURFACE FRONT THAT WILL BE CAPABLE OF STRONG WIND GUSTS AND MARGINALLY SEVERE HAIL. ACTIVITY WILL CONTINUE MOVING NEWD INTO TONIGHT IN RESPONSE TO INCREASING LOW LEVEL CONVERGENCE/WARM ADVECTION IN ASSOCIATION WITH A STRENGTHENING NOCTURNAL LOW LEVEL JET OVER THE NRN PLAINS. ...WRN WY THIS AFTERNOON/EVENING... POST-FRONTAL UPSLOPE FLOW WILL ENCOURAGE ISOLATED TSTM DEVELOPMENT BY AFTERNOON WITHIN A STEEP LAPSE RATE AND AT LEAST MARGINALLY UNSTABLE THERMODYNAMIC ENVIRONMENT. THIS INSTABILITY WILL ALIGN WITH MODESTLY STRONG MID TO UPPER-TROPOSPHERIC FLOW WHICH MAY BE CONDUCIVE FOR A FEW SEVERE STORMS CAPABLE OF HAIL AND LOCALLY STRONG WIND GUSTS. ...FL THIS AFTERNOON... SCATTERED AFTERNOON TSTM DEVELOPMENT IS ANTICIPATED ALONG THE DEVELOPING SEA BREEZE FRONTS. WINDS ALOFT REMAIN QUITE WEAK /AOB 10 KT THROUGH 500 MB/ SUGGESTING INITIAL STORMS WILL EXHIBIT PULSE CHARACTERISTICS. HOWEVER...SOME CONVECTION-ALLOWING MODEL GUIDANCE SHOW SOME STORMS POTENTIALLY GROWING UPSCALE INTO WWD-MOVING CLUSTERS. THE COMBINATION OF A VERY MOIST AIR MASS AND ATTENDANT PRECIPITATION-LOADING EFFECTS MAY ENHANCE MICROBURST POTENTIAL...WHILE 500 MB TEMPERATURES OF AROUND -10 C WILL LOCALLY STRONGER UPDRAFTS AND A THREAT FOR MARGINAL HAIL. ...CAROLINAS AND SOUTHWEST VA THIS AFTERNOON/EVENING... VISIBLE IMAGERY SHOWS CU AND ISOLATED DEEP CONVECTION BEGINNING TO DEVELOP OVER THE CENTRAL APPALACHIANS AT THIS TIME AS CONTINUED HEATING OF A MOIST AIR MASS SURFACE DEW POINTS IN THE 60S OCCURS OVER THE HIGHER TERRAIN. WIDELY SCATTERED TO SCATTERED TSTMS ARE EXPECTED TO CONTINUE DEVELOPING INVOF THE STALLED SURFACE FRONT AND SPREAD SEWD ALONG THE SRN EDGE OF WEAK NWLY FLOW ALOFT. ALTHOUGH WEAK VERTICAL SHEAR WILL LIKELY LIMIT STORM ORGANIZATION/LONGEVITY...ISOLATED OCCURRENCES OF HAIL/LOCALLY DAMAGING WINDS ARE POSSIBLE. ...CNTRL GULF COAST... THE 12Z LIX SOUNDING SAMPLED A MOIST...MODERATELY UNSTABLE AIR MASS WITH A PW OF 1.8 INCHES AND MLCAPE OF AROUND 1600 J/KG. CONTINUED HEATING AHEAD OF A CONVECTIVE BAND FROM SRN MS INTO SERN LA IS EXPECTED TO INCREASE CAPE TO ABOVE 2000 J/KG THIS AFTERNOON. RELATIVELY WEAK BUT VEERING LOW LEVEL WINDS COUPLED WITH LOW LCL HEIGHTS MAY SUPPORT TRANSIENT MESOCYCLONES IN THE STORMS OVER SERN LA/SERN MS/SWRN AL COAST...WITH A CONTINUED THREAT FOR A BRIEF TORNADO OR TWO THIS AFTERNOON. ...ERN NY INTO NEW ENGLAND... A STRONG MID/UPPER LEVEL JET STREAK IS PROGRESSING SSEWD ACROSS CENTRAL NY ON THE WEST SIDE OF THE COLD UPPER TROUGH MOVING SLOWLY EWD ACROSS NEW ENGLAND. CONVECTION HAS BEEN DEVELOPING FROM THE ST LAWRENCE VALLEY INTO NERN NY AND NEW ENGLAND WITHIN THE LEFT EXIT REGION OF THE JET STREAK. ALTHOUGH MOISTURE IS MARGINAL WITH SURFACE DEW POINTS ONLY NEAR 50...COOLING ALOFT WILL RESULT IN SBCAPE REACHING NEAR 500 J/KG THIS AFTERNOON WITH AN INCREASE IN LOW-TOPPED CONVECTION/THUNDERSTORMS EXPECTED. STRONGER CELLS MAY BE CAPABLE OF PRODUCING MAINLY SMALL HAIL AND STRONG WIND GUSTS THROUGH THE AFTERNOON HOURS. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |