[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 271749
SWOMCD
SPC MCD 271749 
NJZ000-DEZ000-MDZ000-VAZ000-PAZ000-DCZ000-272015-

MESOSCALE DISCUSSION 1781
NWS STORM PREDICTION CENTER NORMAN OK
1249 PM CDT TUE JUL 27 2004

AREAS AFFECTED...SERN VA...SRN/ERN MD...DE AND FAR SRN NJ

CONCERNING...CONVECTIVE TRENDS AND HEAVY RAINFALL 

VALID 271749Z - 272015Z

ISOLATED STORMS WILL CONTINUE TO INTENSIFY AND MAY POSE A THREAT FOR
DAMAGING WINDS OVER THE NEXT FEW HOURS. THREAT WILL REMAIN LIMITED
ENOUGH THAT A WW IS NOT LIKELY.

EARLY AFTERNOON SFC ANALYSIS PLACES A SFC LOW PRESSURE CENTER OVER
FAR SERN PA WITH A STATIONARY FRONTAL BOUNDARY EXTENDING SEWD FROM
THE LOW INTO FAR SRN NJ. A THERMAL RIDGE EXISTED SOUTH OF THE LOW
WITH TEMPERATURE READINGS IN THE LOWER-MID 80S AND DEWPTS IN THE
LOWER TO MID 70S. THIS WAS CONTRIBUTING TO MODERATE INSTABILITY WITH
MUCAPES FROM 2000-2500 J/KG. SUBTLE MID LEVEL SPEED MAX SAMPLED BY
AREA VWP/S WILL CONTINUE TO SUPPORT AROUND 30 KTS OF FLOW AT 2-3 KM
AND AROUND 40 KTS AT 6 KM OVER THE REGION THROUGH THE AFTERNOON.
ALTHOUGH MID LEVEL LAPSE RATES WERE MUCH POORER OVER WRN
VA/MD...RIBBON OF AROUND 6.5 C/KM LAPSE RATES NOTED ON RECENT RUC
SOUNDINGS AND WV IMAGERY SHOULD MOVE NWD INTO THE AREA ENHANCING
UPDRAFT STRENGTH. THE PARALLEL NATURE OF UNIDIRECTIONAL SHEAR
PROFILES WITH ORIENTATION OF DIFFERENTIAL HEATING/CONVECTIVE GENESIS
BOUNDARY EXTENDING FROM SRN MD INTO SCENTRAL VA SUGGESTS THAT IT
WILL TAKE A FEW MORE HOURS FOR CONVECTION TO ALIGN ITSELF FAVORABLY
TO DEEP SHEAR VECTOR AND BEGIN POSING A THREAT FOR ISOLATED DAMAGING
WINDS.

IN ADDITION...ANY STORMS THAT DEVELOP/STRENGTHEN FURTHER EAST ALONG
THE SEA BREEZE FRONT ACROSS THE WRN DELMARVA PENINSULA AND/OR THE
STATIONARY BOUNDARY OVER FAR NRN DE/SRN NJ WILL HAVE THE POTENTIAL
TO BECOME BRIEFLY SUPERCELLULAR GIVEN BACKED LOW LEVEL SHEAR
PROFILES IN THESE AREAS. SUSTAINED LIFT AND CONVERGENCE ALONG THE
STATIONARY FRONT COUPLED WITH VERY MOIST LOW LEVEL AIRMASS WITH PWAT
VALUES AROUND 1.8 IN. WILL LIKELY LEAD TO HEAVY RAINFALL RATES
LOCALLY OVER 2 INCH/HR.

..CROSBIE.. 07/27/2004

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

ATTN...WFO...PHI...AKQ...CTP...LWX...

36987583 36727771 37377801 38797730 39627653 39937569
39437437 

WWWW