The NOAA Storm Prediction Center continues to keep an eye on the potential for microbursts or tornadoes in Southern New England on Friday afternoon. While conditions are not completely favorable for severe weather, there is a “non-zero” threat for part of Southern New England regarding tornadoes. Basically, it means that given the dynamics of the cold front passing through Southern New England there is the outside chance of seeing a microburst (strong straight line winds) or tornado in a severe thunderstorm.
The Storm Prediction Center says it is unlikely that they will issue a Severe Thunderstorm Watch.
Technical discussion below
NWS STORM PREDICTION CENTER NORMAN OK 1225 PM CDT FRI AUG 09 2013 AREAS AFFECTED...PART OF SERN NY/CT/MA/NRN RI/FAR SRN NH CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 091725Z - 091930Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...TSTMS MOVING ENEWD ACROSS SRN NEW ENGLAND THIS AFTERNOON WILL POSE A THREAT FOR WET MICROBURSTS...A FEW POTENTIALLY PRODUCING DAMAGING WIND GUSTS...WHILE A NONZERO THREAT EXISTS FOR A FUNNEL/BRIEF...WEAK TORNADO. GIVEN THE LOW SEVERE WEATHER THREAT...A WATCH ISSUANCE IS NOT WARRANTED...THOUGH CONVECTIVE TRENDS WILL BE MONITORED. DISCUSSION...SINCE 16Z...REGIONAL RADAR IMAGERY OVER SERN NY INTO WRN/NRN CT AND PARTS OF CENTRAL MA HAVE INDICATED RELATIVELY BROAD LOW-MID LEVEL ROTATION COUPLETS WITH A BAND OF TSTMS EMBEDDED IN A LARGER CLOUD/PRECIPITATION SHIELD ACROSS SRN NEW ENGLAND. THESE STORMS APPEAR TO BE ATTENDANT TO A PROGRESSIVE MIDLEVEL IMPULSE MOVING ACROSS SERN NY/CT ATTM AND FURTHER AIDED BY LARGE SCALE ASCENT AHEAD OF THE UPSTREAM TROUGH TRACKING THROUGH THE LOWER GREAT LAKES STATES. ALTHOUGH THE EXTENSIVE CLOUDINESS AND WEAK LAPSE RATES WILL LIMIT STRONGER DESTABILIZATION TODAY...STRONG EFFECTIVE BULK SHEAR TO AROUND 40 KT WILL SUPPORT ORGANIZATION AS INDICATED BY THE ONGOING UPDRAFT ROTATION. VERTICALLY VEERING WIND PROFILES PER AREA WSR-88D VADS AT OKX/BOX SHOWED LOW LEVEL HODOGRAPH CURVATURE/LOW LEVEL SHEAR SUFFICIENT FOR A TORNADO THREAT. THE WEAK INSTABILITY IS EXPECTED TO LIMIT STORM INTENSITIES...THOUGH AFOREMENTIONED KINEMATICS AND A VERY MOIST AIR MASS /PW AROUND 2 INCH/ SUGGEST WET MICROBURSTS WILL BE POSSIBLE AND A BRIEF/WEAK TORNADO CANNOT BE RULED OUT.