MESO: Mesoscale Discussion 1973

ACUS11 KWNS 172236
SWOMCD
SPC MCD 172236
PAZ000-180030-

MESOSCALE DISCUSSION 1973
NWS STORM PREDICTION CENTER NORMAN OK
0536 PM CDT THU OCT 17 2013

AREAS AFFECTED...CENTRAL/EASTERN PA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 172236Z - 180030Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED CONVECTIVELY-RELATED DAMAGING WIND GUST CANNOT
BE RULED OUT THIS EVENING ACROSS CENTRAL TO EASTERN PORTIONS OF
PA...BUT A WATCH WILL NOT BE NEEDED.

DISCUSSION...A LOW-TOPPED CONVECTIVE LINE HAS SHOWN A RECENT
ORGANIZATIONAL INCREASE /ESPECIALLY SINCE 2130Z/ ACROSS WEST-CENTRAL
PORTIONS OF PA...ESPECIALLY FROM NEAR THE DUBOIS AREA
SOUTH-SOUTHWESTWARD TO JOHNSTOWN PA AS OF 2220Z. THIS IS OCCURRING
NEAR A GRADUALLY DEEPENING SURFACE LOW /1004 MB/ AND COLD
FRONT...WITH A PRECEDING CORRIDOR OF 2-3 MB/2HR PRESSURE FALLS
ACROSS CENTRAL PA. AN ALREADY LIMITED BUOYANCY PROFILE WILL BE
FURTHER HINDERED BY AN EARLY EVENING TREND OF COOLING SURFACE
TEMPERATURES. EVEN SO...SOME ADDITIONAL ORGANIZATION/MODEST
ACCELERATION OF THE LOW-TOPPED CONVECTIVE LINE MAY OCCUR IN
ASSOCIATION WITH DYNAMIC FORCING FOR ASCENT AND CONTINUED SURFACE
CYCLOGENESIS/AMPLE VERTICAL SHEAR. THE WIND PROFILE FROM THE STATE
COLLEGE /KCCX/ WSR-88D VWP INDICATES 50+ KT SOUTHWESTERLY WINDS
WITHIN THE LOWEST 1-2 KM. EVEN WITH LIMITED BUOYANCY...SOME
NEAR-SURFACE CINH...AND LITTLE OR NO CLOUD-GROUND LIGHTNING...A FEW
LOCALLY DAMAGING WIND GUSTS CANNOT BE ENTIRELY DISCOUNTED THIS
EVENING GIVEN THE MAGNITUDE OF THE LOWER-MIDDLE TROPOSHERIC WINDS.

..GUYER/EDWARDS.. 10/17/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...BGM...CTP...

LAT...LON 41147799 41497759 41607618 41317560 40527548 39767663
39837831 40407824 41147799

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