Powerful Storm in the Western U.S.; Heavy Rain and Flooding Threat Across the Central Gulf Coast

A powerful storm system will continue to bring heavy mountain snow, rain, and high winds to the Pacific Northwest and northern California through midweek. Heavy rain and flash flooding potential exists across the central Gulf Coast over the next few days, including the Florida Panhandle. A Slight Risk (level 2 of 4) of excessive rainfall is in effect Tuesday. Read More >

Overview

On July 15, 2012, a short-wave moving through a ridge brought a surge of moisture and anomalously high precipitable water to Pennsylvania. This influx of moisture caused a surge of CAPE values over the region and led to the formation of two bow echoes, one developing over central PA and moving eastward, the other forming in southern PA and primarily impacting Harrisburg. With the exception of two tornadoes in Bradford County, PA and St Mary’s County, MD, the event was dominated by low-end wind damage and reports of fallen trees.


Surface Map 7/15/20	WPC National Forecast Chart	500-mb Analysis 7/15/20

24-H QPF 7/15/20 0Z - 7/16/20 0Z	WPC Analysis/Radar Composite 18Z	SPC Storm Reports for 07/15/12

KCCX radar at 2103 UTC 7/15/12. Upper left shows 0.5 degree reflectivity, upper right shows 0.50 degree velocity, lower right shows storm relative velocity and lower left shows the terrain. Arrow shows origin of bow and its approximate path.