NWS Mesoscale Discussion
SPC MD 780
MD 0780 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF THE UPPER OH VALLEY/CNTRL APPALACHIANS
MESOSCALE DISCUSSION 0780
NWS STORM PREDICTION CENTER NORMAN OK
1050 AM CDT THU MAY 23 2013
AREAS AFFECTED...PARTS OF THE UPPER OH VALLEY/CNTRL APPALACHIANS
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 231550Z - 231745Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...ISOLATED DAMAGING WIND/MARGINAL SEVERE HAIL HAZARD SHOULD
DEVELOP AS CONVECTION DEEPENS ACROSS THE UPPER OH VALLEY. WEAKER
DEEP-LAYER FLOW RELATIVE TO AREAS NEWD MAY TEMPER THE OVERALL
COVERAGE/INTENSITY OF THE THREAT.
DISCUSSION...AN ARC OF SHOWERS AND ISOLATED TSTMS HAVE DEVELOPED
FROM 30 E ZZV NEAR HTS ALONG A RELATIVELY DIFFUSE COLD FRONT. A
DEEPENING CU FIELD WAS NOTED IN VISIBLE SATELLITE IMAGERY AHEAD OF
THE FRONT FROM ERN KY INTO WRN PA. AS SURFACE TEMPERATURES CONTINUE
TO WARM THROUGH THE 70S...MLCAPE SHOULD APPROACH 1000 J/KG GIVEN THE
EXPECTED MAINTENANCE OF LOWER 60S SURFACE DEW POINTS.
HOWEVER...MORNING MODEL GUIDANCE REMAINS INSISTENT THAT 700 MB WINDS
WILL SUBSIDE THIS AFTERNOON. WITH EFFECTIVE SHEAR AROUND 30 KT AT
PRESENT...OVERALL SETUP WILL MOST LIKELY YIELD A FEW MULTICELL
CLUSTERS CAPABLE OF ISOLATED DAMAGING WINDS AND MARGINALLY SEVERE
HAIL.
..GRAMS/KERR.. 05/23/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CTP...LWX...RNK...PBZ...RLX...
LAT...LON 37908226 38298240 39048169 39808124 40458105 40918040
41067943 40957854 40777825 40337834 39527892 38158013
37738095 37628167 37908226
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SPC MD 779
MD 0779 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF THE UPPER MID-ATLANTIC/SRN NEW ENGLAND
MESOSCALE DISCUSSION 0779
NWS STORM PREDICTION CENTER NORMAN OK
1023 AM CDT THU MAY 23 2013
AREAS AFFECTED...PARTS OF THE UPPER MID-ATLANTIC/SRN NEW ENGLAND
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 231523Z - 231800Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...MONITORING FOR AN INCREASING DAMAGING WIND/MARGINAL SEVERE
HAIL HAZARD WITH INITIAL CONVECTIVE DEVELOPMENT OCCURRING ACROSS FAR
ERN PA/NRN NJ. A WW ISSUANCE MAY BECOME NECESSARY WHERE GREATER
CLUSTER/LINEAR ORGANIZATION IS APPARENT.
DISCUSSION...AN INCREASE IN CONVECTIVE DEVELOPMENT HAS BEEN NOTED IN
RADAR IMAGERY FROM NEAR THE ABE/TTN TO 20 NW EWR AREA AS CONVECTIVE
TEMPERATURES OFF THE 12Z APG/WAL RAOBS HAVE BEEN BREACHED WITH
MIDDLE TO UPPER 70S IN 15Z METARS. AMIDST A PLUME OF MIDDLE TO UPPER
60S SURFACE DEW POINTS...MLCAPE HAS ALREADY REACHED 500-1000 J/KG.
MODERATELY STRONG UNIDIRECTIONAL SWLY WIND PROFILES WITHIN THE RIGHT
ENTRANCE REGION OF A FAST UPPER-LEVEL JET SHOULD PROMOTE ADDITIONAL
CONVECTION WHICH MAY ORGANIZE INTO CLUSTERS AND SHORT-LINE SEGMENTS
PRIMARILY PRODUCING SPORADIC DAMAGING WINDS AND MARGINALLY SEVERE
HAIL.
..GRAMS/KERR.. 05/23/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...
LAT...LON 43067382 43317289 43077200 42707193 42077223 41467298
41107349 40717386 40247443 40187490 40487540 40767527
42097440 43067382
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SPC MD 778
MD 0778 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WRN/CNTRL/NRN PORTIONS OF NY/PA
MESOSCALE DISCUSSION 0778
NWS STORM PREDICTION CENTER NORMAN OK
0957 AM CDT THU MAY 23 2013
AREAS AFFECTED...WRN/CNTRL/NRN PORTIONS OF NY/PA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 231457Z - 231730Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...MONITORING FOR AN INCREASING DAMAGING WIND/MARGINAL SEVERE
HAIL HAZARD TODAY WITH INITIAL CONVECTIVE DEVELOPMENT OCCURRING WRN
NY INTO NWRN PA. A WW ISSUANCE MAY BECOME NECESSARY WHEN GREATER
CLUSTER/LINEAR ORGANIZATION IS APPARENT.
DISCUSSION...AN INCREASE IN CONVECTIVE DEVELOPMENT HAS BEEN NOTED IN
RADAR/VISIBLE SATELLITE IMAGERY FROM NEAR ROC SWWD TO FKL. AS
CONVECTIVE TEMPERATURES OFF THE 12Z BUF/PIT RAOBS HAVE BEEN
BREACHED. RELATIVELY ABUNDANT LOW CLOUD COVERAGE REMAINS DOWNSTREAM
OF THIS WHICH IS RETARDING SURFACE HEATING...BUT GRADUAL
DESTABILIZATION AMIDST THE PRESENCE OF 10-12 G/KG MEAN MIXING RATIOS
MAY YIELD POCKETS OF MLCAPE FROM 500-1000 J/KG. MODERATELY STRONG
UNIDIRECTIONAL SWLY WIND PROFILES WITHIN THE RIGHT ENTRANCE REGION
OF A FAST UPPER-LEVEL JET SHOULD PROMOTE ADDITIONAL CONVECTION WHICH
MAY ORGANIZE INTO CLUSTERS AND SHORT-LINE SEGMENTS.
..GRAMS/KERR.. 05/23/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...
LAT...LON 43167705 43597626 44167566 44447522 44337450 43977408
43407431 42267535 41557649 40617833 40587921 40907967
41357969 43167705
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