Mesoscale Discussion 939

Issued

May 28, 2012, 2:25 PM EDT (18:25 UTC)

Expired

May 28, 2012, 3:30 PM EDT

In force

65 min

Issued by

the Storm Prediction Center

Chance of a watch

20%

The Binghamton radar (KBGM), 83 km from the middle of the area, began a volume at 18:28 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

230 
ACUS11 KWNS 281825
SWOMCD
SPC MCD 281825 
CTZ000-NYZ000-NJZ000-PAZ000-OHZ000-281930-

MESOSCALE DISCUSSION 0939
NWS STORM PREDICTION CENTER NORMAN OK
0125 PM CDT MON MAY 28 2012

AREAS AFFECTED...LK ERIE SHORE...TWIN TIERS INTO SERN NY...NRN
NJ...SRN NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 281825Z - 281930Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...WITH THE DECAY OF THE EARLIER MCS...CONVECTIVE INITIATION
NOW REMAINS SOMEWHAT UNCERTAIN. SEVERAL SCENARIOS REMAIN
POSSIBLE...INCLUDING ADDITIONAL DEVELOPMENT AHEAD OF THE REMNANT MCS
IN SERN NY AND SRN NEW ENGLAND...AND DEVELOPMENT ALONG THE
STATIONARY FRONT/OUTFLOW MERGER OR LAKE BREEZE FARTHER W. GIVEN THE
CONSIDERABLE UNCERTAINTY IN INITIATION...THE NEED FOR A WW IS NOT
IMMEDIATELY APPARENT...THOUGH TRENDS ARE BEING MONITORED CLOSELY.

DISCUSSION...ILL TIMING OF THE EARLIER MCS HAS LED TO ITS
WEAKENING...NOW CLEARLY EVIDENT BY ITS APPEARANCE ON 1730Z SATELLITE
IMAGERY AND BY A LACK OF LIGHTNING. HOWEVER...AHEAD OF THE WEAK
UPPER WAVE THAT INITIATED THE MCS...LIGHTNING IS NOW NOTED IN
HARTFORD COUNTY CT. ALTHOUGH MESOANALYSIS REFLECTS AN UNCAPPED AIR
MASS...THE 12Z BUF SOUNDING AND SUPPORTING MODEL FORECASTS DEPICT A
WARM LAYER AT 700 MB THAT MAY BE SUPPRESSING DEEP MOIST CONVECTION.
ALTHOUGH SEVERAL MODEL FORECASTS ERODE THIS LAYER...OBSERVATIONAL
DATA SUGGESTS IT IS CURRENTLY UNCLEAR WHETHER LOW-LEVEL
MOISTENING/DESTABILIZATION WILL BE SUFFICIENT TO OVERCOME THE CAP.
HOWEVER...A SWD SAGGING COLD FRONT FROM NEW ENGLAND MAY ALSO PROVIDE
ENHANCED SURFACE CONVERGENCE FOR CONVECTIVE DEVELOPMENT LATER TODAY.

FARTHER W...A REMNANT OUTFLOW BOUNDARY FROM THE EARLIER MCS IS
MERGING WITH THE WARM FRONT ACROSS THE TWIN TIERS...WITH MORE RECENT
RADAR IMAGERY INDICATING ATTEMPTS AT INITIATION FROM SCHUYLER TO
BRADFORD COUNTY. WITH THE INITIAL UPPER WAVE PROGRESSING AWAY FROM
THE AREA...FORCING FOR ASCENT MAY BE DELAYED UNTIL THE NEXT SUBTLE
FEATURE...OBSERVED ON 1730Z WV IMAGERY APPROACHING LK ONTARIO. THE
BROADER UPPER RIDGE CASTS UNCERTAINTY ON COVERAGE.

REGARDLESS...IF STORMS CAN DEVELOP...STEEP LOW-MID LEVEL LAPSE RATES
AND MODEST WNWLYS ALOFT /PARTICULARLY ACROSS NY AND SRN NEW ENGLAND/
MAY SUPPORT SEMI-ORGANIZED BOWING SEGMENTS AND WEAK SUPERCELLS.

..HURLBUT/CARBIN.. 05/28/2012

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

ATTN...WFO...BOX...OKX...ALY...PHI...BGM...BUF...CTP...PBZ...
CLE...

LAT...LON   42757870 42727703 42307506 41757337 41657264 41377233
            40907362 40897485 41067610 41307764 41397841 41677997
            41478072 41908064 42497923 42757870

Mesoscale Discussions in New York, 2012Mesoscale Discussions in Pennsylvania, 2012Mesoscale Discussions in Connecticut, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.