SPC MD 1477

By Newsroom America Feeds at 12 Aug 2017

MD 1477 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CENTRAL PA...CENTRAL NY
Mesoscale Discussion 1477 NWS Storm Prediction Center Norman OK 1241 PM CDT Sat Aug 12 2017 Areas affected...Central PA...Central NY Concerning...Severe potential...Watch possible Valid 121741Z - 121945Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorm coverage is expected to continue increasing over the next few hours. Some hail and damaging wind gusts are possible with the stronger, more organized cells and trends will be monitored for possible watch issuance. DISCUSSION...Thunderstorm activity has increased across central PA and central NY over the past hour or so within a broad region of surface confluence ahead of an approaching cold front. Low-level airmass ahead of the cold front is characterized by dewpoints in the upper 60s/low 70s, which is supporting modest instability (i.e. MLCAPE around 1000 J/kg per the latest mesoanalysis), despite filtered sunshine and warm mid-level temperatures. General expectation is for MLCAPE to remain around 1000 J/kg with increasing storm coverage as both the cold front and its parent shortwave trough continue eastward into the region. Despite modest the instability, occasionally strong/organized updrafts are possible given the strengthening mid-level flow and related moderate shear. Recent CCX VAD sampled 0-6 km bulk shear over 45 kt and a long hodograph, favorable for storm splits. Some hail will be possible with the any stronger/discrete cells with gusty winds also possible as multicell storms organize in small bowing structures. Convective trends will be monitored for possible watch issuance. ..Mosier/Guyer.. 08/12/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ALY...PHI...BGM...BUF...CTP...LWX...PBZ... LAT...LON 42747788 43427626 43067457 41027579 39767695 39687939 42747788 Read more

http://www.spc.noaa.gov/products/md/md1477.html

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