Wednesday, September 29, 2010

Tropical Storm Nicole

Since my last update, Tropical Depression #16 was upgraded to Tropical Storm Nicole at 11AM Wednesday with maximum sustained winds of 40 mph. Nicole is tracking over western Cuba and will clip southern Florida today. Nicole will lose its tropical characteristics as it approaches North Carolina tomorrow, meaning that we will receive Nicole's remnants in Virginia through Thursday night. The system is still expected to merge with a frontal boundary along the Southeast and lift rapidly northeast early Friday. The Flash Flood Watch remains in effect for nearly the entire Commonwealth, with 2"-4" of rainfall expected by late Thursday as a result of the moisture plume feeding into Virginia from the Atlantic. Isolated higher totals are possible if any embedded thunderstorms occur, especially along and east of I-95.

Flash Flood Watch Tonight-Thursday

A Flash Flood Watch is in effect for nearly the entire Commonwealth for heavy rain expected, mainly tonight through Thursday as Tropical Storm Nicole (just upgraded at 11AM) hurls tropical moisture into the region. Here is the visible satellite image of the storm (the surface center is moving over western Cuba now):
We are already getting our first rounds of rain this Wednesday morning as moisture surges from the Atlantic through the Southeast into Virginia. Periods of heavy rain will be likely off and on the rest of today, so keep your umbrella handy. You can see the cloud-cover expanding into Virginia here:
The prolonged heavy rain event will start overnight and continue most of Thursday as the tropical low pressure system tracks toward Virginia. The low itself will track over Virginia late Thursday into early Friday, ending our rain pre-dawn Friday. Tropical Storm Nicole will rapidly merge with the stalled front along the southeast coastline, which will only enhance moisture transport and heavy rainfall from the Carolinas into Virginia. In Virginia's watch area, 2"-4" is possible through Thursday, with locally lesser and higher amounts possible. Embedded thunderstorms overnight into Thursday would lead to higher local rainfall accumulations. Wind shouldn't be a major concern widespread, as this is a "weak" system wind-wise, with maximum sustained winds right now of 35 mph. In Virginia, we're expecting sustained winds of 10-20 mph in central Virginia, with 20-30 mph sustained winds in the Peninsulas, and 40mph sustained winds in the Bay and Eastern Shore. Flash flooding in heavily paved cities and poorly drained areas will be our main concern overnight through Thursday.