Here is todays thunderstorm outlook issued by The National Weather Service in Norman, Oklahoma... DAY 1 CONVECTIVE OUTLOOK AMEND 1 NWS STORM PREDICTION CENTER NORMAN OK 0257 PM CDT THU JUL 03 2014 VALID 032000Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID-ATLANTIC STATES INTO WRN/NRN NEW ENGLAND... ...THERE IS A SLGT RISK OF SVR TSTMS ALONG THE NC COAST... AMENDED TO ADD ISOLATED WIND TO ARIZONA ...SUMMARY... SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING OVER PARTS OF THE MID-ATLANTIC STATES AND NEW ENGLAND...WITH DAMAGING WIND GUSTS AND HAIL THE MAIN THREATS. FARTHER SOUTH...HURRICANE ARTHUR MAY PRODUCE A COUPLE TORNADOES OVER COASTAL AREAS OF NORTH CAROLINA. ISOLATED STRONG TO SEVERE STORMS ALSO MAY OCCUR OVER THE NORTHERN ROCKIES AND ADJACENT HIGH PLAINS...AS WELL AS OVER NORTHERN FLORIDA AND SOUTHERN GEORGIA. ISOLATED STRONG WINDS COULD ALSO MATERIALIZE OVER ARIZONA. ...LITTLE CHANGE WAS MADE TO THE PREVIOUS OUTLOOK REGARDING SEVERE STORMS ACROSS MUCH OF THE NE AND MID-ATLANTIC INCLUDING A LOW-END TORNADO THREAT COASTAL NC WITH ARTHUR. ...NRN FL/SRN GA... A HIGHLY UNSTABLE AIR MASS ACROSS NRN FL/SRN GA IS OVERTURNING IN A ZONE OF WEAK CONFLUENCE WITH STRONG TO SEVERE STORMS ONGOING. TALL STORMS WITH HIGH MOISTURE CONTENT IN AN OTHERWISE WEAK FLOW ENVIRONMENT SHOULD CONTINUE TO FAVOR LOCALLY SEVERE WET MICROBURSTS CAPABLE OF WIND DAMAGE AND HAIL UP TO 1 INCH DIAMETER THROUGH THE AFTERNOON. ...CNTRL/SRN AZ... STORMS ARE BEGINNING TO FORM ALONG THE RIM AND ACROSS SERN AZ. CONTINUED STRONG HEATING WILL REDUCE CIN AND EVENTUALLY ALLOW THESE STORMS TO PROPAGATE IN A SWWD DIRECTION LATER TODAY. THE LARGE T/TD SPREADS AND DEEPLY MIXED BOUNDARY LAYER MAY SUPPORT AN ISOLATED STRONG/SEVERE WIND GUST. ..JEWELL.. 07/03/2014 .PREV DISCUSSION... /ISSUED 1127 AM CDT THU JUL 03 2014/ ...SYNOPTIC SETUP... GRT LKS/OH VLY TROUGH WILL PROGRESS SLOWLY E THROUGH FRI AS SHORTWAVE IMPULSE NOW OVER OH SHEARS NNE INTO WRN QUE AND UPSTREAM DISTURBANCE NOW IN MN CONTINUES SE INTO IND. FARTHER W...UPR LOW ALONG THE BC CST SHOULD ELONGATE EWD INTO AB...ENHANCING WSW FLOW OVER THE NRN RCKYS...AND DEAMPLIFYING DOWNSTREAM RIDGE OVER THE NRN PLNS. ELSEWHERE...NHC FCSTS HRCN ARTHUR TO GRAZE THE NC CST AS IT ACCELERATES NNE AND...LATER...NEWD THROUGH EARLY FRI. AT LWR LVLS...MORNING ANALYSES SHOW SECONDARY COLD FRONTAL SURGE /ASSOCIATED WITH OH UPR IMPULSE/ NOW NEARING THE WRN SLOPES OF THE CNTRL APPALACHIANS. THIS BOUNDARY SHOULD CONTINUE E INTO CNTRL PORTIONS OF NY/PA...AND INTO WRN MD/VA LATER TODAY...OVERTAKING OLDER/WEAKER BOUNDARY STALLED OVER THE REGION. IN THE WEST...LEE CYCLONE/TROUGH WILL STRENGTHEN OVER MT AS WLY FLOW INCREASES ALOFT. ...MID-ATLANTIC/NEW ENGLAND THIS AFTN/EVE... SFC HEATING OF VERY MOIST /PW 1.75-2.00 INCHES/...MODERATELY SHEARED ENVIRONMENT SHOULD PROMOTE ANOTHER ROUND OF NUMEROUS DIURNAL STORMS ALONG AND AHEAD OF CNTRL/NRN APPALACHIANS COLD FRONT. DEVELOPMENT LIKELY ALSO WILL BE FOSTERED BY NNE-MOVING OH UPR IMPULSE. WIND PROFILES OVER THE REGION ARE SLIGHTLY STRONGER BUT SOMEWHAT BACKED RELATIVE TO YESTERDAY...WITH 35-40 KT SWLY DEEP SHEAR EXPECTED TO PERSIST THROUGH THIS EVE FROM WRN/NRN VA NEWD INTO WRN/NRN NEW ENGLAND. OVERALL SETUP APPEARS SIMILAR TO YESTERDAY...WITH THE GREATEST OVERLAP OF BUOYANCY AND DEEP SHEAR FAVORABLE FOR SUSTAINED STORMS/TRANSIENT SUPERCELLS SHIFTED A BIT SWWD INTO CNTRL/ERN PA AND SERN NY. UPSCALE ORGANIZATION OF THE CONVECTION INTO CLUSTERS/BANDS APPEARS LIKELY...WITH A RISK FOR DMGG WIND...MARGINALLY SVR HAIL...AND PERHAPS A TORNADO. ...NC CST TODAY THROUGH EARLY FRI... LATEST NHC FCST TRACK FOR HRCN ARTHUR WILL ALLOW QUADRANT OF THE CIRCULATION MOST FAVORABLE FOR LOW-LVL MESOCYCLONE DEVELOPMENT TO AT LEAST GRAZE THE FAR ERN PARTS OF NC LATER TODAY INTO TNGT. UPDRAFTS IN THE INITIAL OUTER CONVECTIVE BANDS NOW AFFECTING THE CAPE FEAR/CAPE LOOKOUT AREA APPEAR TO LARGELY BE OUTFLOW-DRIVEN. HOWEVER...CELLS WITH A GREATER LOW-LVL MESOCYCLOGENESIS POTENTIAL MAY MOVE/DEVELOP NWWD INTO THE AREA A BIT LATER TODAY THROUGH TNGT AS ENVELOPE OF MORE SHELTERED HIGH THETA-E AIR MORE DIRECTLY ASSOCIATED WITH ARTHUR NEARS THE CST /REF MCD 1260/. GIVEN STRENGTH OF LOW-LVL SHEAR...QUALITY OF LOW-LVL MOISTURE...AND THE PROXIMITY OF THE GULF STREAM STORM UPDRAFTS...A CONDITIONAL RISK MAY DEVELOP FOR TORNADOES AND/OR WATERSPOUTS. ...NRN RCKYS/ADJACENT HIGH PLNS THIS AFTN/EVE... WEAK HEIGHT FALLS ASSOCIATED WITH FLATTENING OF DOWNSTREAM NRN PLNS RIDGE WILL PROVIDE MODEST LARGE SCALE ASCENT ACROSS ID/MT TODAY AS LEE TROUGH/LOW-LVL PRESSURE GRADIENT SOMEWHAT STRENGTHEN. ASCENT ALSO MAY BE ENHANCED IN NRN MT BY TAIL END OF UPR IMPULSE LIFTING NEWD INTO AB. MOISTURE WILL REMAIN RELATIVELY SPARSE...WITH PW AROUND 0.75-1.00 IN. BUT COUPLED WITH STRONG DIFFERENTIAL HEATING OF ELEVATED TERRAIN AND STEEP LOW TO MID-LVL LAPSE RATES...EXPECT SCTD AFTN TSTMS OVER THE REGION. 25-30 KT WLY DEEP SHEAR MAY SUPPORT WEAK UPSCALE ORGANIZATION INTO SMALL CLUSTERS/BANDS CAPABLE OF HAIL AND...ESPECIALLY...LOCALLY DMGG WIND GIVEN WELL-MIXED SUB CLOUD LAYERS. FARTHER S...ISOLD TO SCTD DRY TSTMS MAY OCCUR FROM THE NRN INTERMOUNTAIN REGION ACROSS THE ERN GRT BASIN TO THE FOUR CORNERS AND NRN AZ...WHERE A TRANSITION TO MORE MOIST...SW-U.S. MONSOON-TYPE OF CONVECTION IS EXPECTED OVER SRN AZ AND NM.
Posted on: Thu, 03 Jul 2014 20:51:50 +0000
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