Mesoscale Discussion 1613

Issued

Jul 26, 2012, 6:04 PM EDT (22:04 UTC)

Expired

Jul 26, 2012, 7:30 PM EDT

In force

86 min

Issued by

the Storm Prediction Center

The Philadelphia radar (KDIX), 135 km from the middle of the area, began a volume at 22:05 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.

218 
ACUS11 KWNS 262205
SWOMCD
SPC MCD 262204
CTZ000-NYZ000-MAZ000-NJZ000-PAZ000-DEZ000-262330-

MESOSCALE DISCUSSION 1613
NWS STORM PREDICTION CENTER NORMAN OK
0504 PM CDT THU JUL 26 2012

AREAS AFFECTED...SOUTHERN/EASTERN PA TO SOUTHEAST NY/NYC METRO AND
SOUTHERN NEW ENGLAND

CONCERNING...TORNADO WATCH 525...

VALID 262204Z - 262330Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 525 CONTINUES.

SUMMARY...TORNADO WATCH 525 CONTINUES UNTIL 01Z AND SEVERE TSTM
WATCH 527 CONTINUES UNTIL 03Z.

SERIOUS CONCERN EXISTS FOR WIDESPREAD SWATHS OF WIND DAMAGE INTO THE
EARLY/MID EVENING HOURS WITHIN WATCHES 525/527. ISOLATED TORNADOES
ALSO REMAIN A CONCERN ESPECIALLY ACROSS SOUTHEAST NY AND ADJACENT
PARTS OF EASTERN PA/NORTHERN NJ...WITH WIDESPREAD WIND DAMAGE
OTHERWISE EXPECTED TO STEADILY SPREAD EAST-SOUTHEASTWARD TOWARD THE
COAST WITH A FAST-MOVING SEVERE MCS/DERECHO.

DISCUSSION...WELL-ORGANIZED QUASI-LINEAR CONVECTIVE SYSTEM /QLCS/
CONTINUES TO STEADILY PROGRESS EAST-SOUTHEASTWARD...FROM NEAR THE
SOUTHEAST NY/NORTHEAST PA BORDER VICINITY SOUTHWESTWARD INTO
SOUTH-CENTRAL PA...WITH THE FASTEST-MOVING BOWING /NORTHEASTERN/
PORTION OF THE LINE MOVING AS FAST AS 45-50 KT. LATEST SUBJECTIVE
SURFACE ANALYSIS REFLECTS A PRESSURE FALL-RISE COUPLET...WITH MODEST
QLCS-LEADING PRESSURE FALLS...AND A 20-25 DEG F COLD POOL ALONG WITH
3 MB/2 HR PRESSURE RISES ACROSS PA IN THE TRAILING STRATIFORM WAKE
REGION OF THE QLCS. COINCIDENT WITH A GRADUAL STRENGTHENING OF MEAN
FLOW OVER THE PAST FEW HOURS...LATEST WSR-88D VWP DATA FROM STATE
COLLEGE IS INDICATIVE OF 50 KT WINDS BETWEEN 2-6 KM IN ASSOCIATION
WITH THE QLCS WAKE REGION.

WITH ADDITIONAL FORWARD PROPAGATION/ACCELERATION AND RESULTANT
BOWING LIKELY...OF FURTHER CONCERN IS THAT THE AIRMASS CONTINUES TO
STEADILY WARM LATE THIS AFTERNOON /AS OF 21Z/ IN TANDEM WITH
CLOUD-FREE SKIES AND THE NORTHEASTWARD ADVANCEMENT OF A WARM FRONT
TOWARD FAR SOUTHEAST NY/NYC METRO AND SOUTHWEST NEW ENGLAND. THESE
THERMODYNAMIC TRENDS...PRESENCE OF THE WARM FRONT...AND EXISTING
ORGANIZED NATURE OF THE MCS/COLD POOL SUGGESTS A VERY HEIGHTENED
WIND DAMAGE/SOME TORNADO POTENTIAL INTO REMAINING PARTS OF SOUTHEAST
NY/NYC METRO/SOUTHWEST NEW ENGLAND AND ADJACENT PARTS OF EASTERN PA
AND NJ.

..GUYER.. 07/26/2012

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

ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...

LAT...LON   40827719 41077610 41637559 42227482 42387265 41577207
            40597259 39727451 39957711 40827719

Mesoscale Discussions in Pennsylvania, 2012Mesoscale Discussions in New Jersey, 2012Mesoscale Discussions in New York, 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.