Premium Weekly Outlook: Monday downpours, then drier weather returns, but a cooler weekend?
A shortwave trough and frontal boundary has move slower into region than previous expected. This has lead to drier conditions through the overnight hours Sunday. But more showers and some steadier bands of rainfall are now over much of the region this morning. Stronger forcing underneath of right-entrance of jet streak and low-level convergence along frontal boundary has increased, along with tropical moisture from the remnants of Julia off the Southeast coast, surge northward along the coast. Some instability with a deep southwesterly flow is also aiding in development of some thunderstorms scattered or embedded within steadier bands of rainfall over region.
With marginal instability and abundant moisture, the main threat continues to be for torrential downpours with localized flash flooding, especially during the morning and early afternoon hours. Much of the area will likely receive near or 1.00” of rainfall. However, some showers and thunderstorms could train along and axis of unidirectional shear, convergence, and precipatable water values near over 2.00”, along or just ahead of the frontal boundary today. Areas at greatest risk for flooding will over poor drainage and low-lying areas. Some ponding on area roadways, especially likely as well. Significant flooding from rivers and streams isn’t anticipated due to drier conditions over the last few weeks.