With all the talk about Florence (check out our special Friday Morning Briefing here), its almost easy to forget tropical depression Gordon. The storms has remained a tropical depression centered over Arkansas as of Friday afternoon. It made landfall as a tropical storm on the central Gulf Coast Tuesday night, and has not moved far from there. Thankfully, an incoming trough out of the Plains will be strong enough to give Gordon a nudge, but unfortunately will track its heavy rains toward the Northeast between now and early-next week.
This Friday will continue to feature an active radar picture with numerous clusters of rain, some of which is heavy, and thunderstorms spanning from the Texas Panhandle to the western Ohio River Valley. Overnight, much of this precipitation should dissipate over the southern Plains while it remains relentless in the Midwest, making for a moderate risk for flash flooding. Not only will there be heavy rain, but it will be falling for several consecutive hours thanks to “training.” Since the widespread precipitation is moving from southwest to northeast, that allows for it to rain for an extended period of time.
Now on Saturday, Gordon will finally get off its very comfy seat over Arkansas, taking a ride toward the Ohio River Valley. Unfortunately, more in the way of heavy rain is ahead for similar areas in the Midwest. It’s going to be an indoors kind of day given the fact it will be a washout across many towns in Illinois, Indiana, and Ohio. It’s also these areas that will feature the greatest chance for flash flooding given how wet it has already been and the additional rainfall forecast.
It will also be wet in surrounding areas with a light rain beginning to work into the Mid-Atlantic, affecting cities like Pittsburgh, Philadelphia, and Washington, DC. New York City will be on the northern edge of this rain, but should not be surprised if occasional rain drops fall from the sky on Saturday.
Now in the Mid-Mississippi River Valley, south of where it will be a washout in the Ohio River Valley, there will likely be the development of a squall line. By midday, a line of heavy rain and thunderstorms is expected to form, spanning from Kentucky through the ArkLaTex and possibly into central Texas. Heavy rain, flash flooding, and gusty winds will be the main concerns associated with this slow-moving line.
By Sunday, Gordon will turn into a Northeast event as the storm transitions from a tropical depression to post-tropical cyclone. A widespread rain, containing pockets of moderate to heavy rainfall, will plague much of the day across the eastern Ohio River Valley and much of the Mid-Atlantic. A lighter rain will attempt to move into southwestern New England, but drier air will prevent the wet weather from arriving until Sunday night. The best risk for flash flooding Sunday into Sunday night will be found in the eastern Ohio River Valley.
The squall line feature will remain in tact, so a line of sub-severe rain and thunderstorms will be possible across the Ohio and Tennessee River Valleys.
The rains will then overspread into New England by Monday, making for a wet start to the week not only in New England but much of the Mid-Atlantic and eastern Ohio River Valley as well. Flash flooding will be a concern in all of these affected areas, but since the Mid-Atlantic has had a wetter summer than New England, the odds favor the Mid-Atlantic for flooding. Hit or miss showers and storms associated with the cyclone’s cold front will be possible to the south across the Southeast.
The rain will begin to become more scattered as high pressure ushers in drier air across the Ohio River Valley and interior Northeast. Lighter showers and storms will remain possible on Tuesday across New England and coastal sections of the Mid-Atlantic, but the risk for flash flooding will thankfully begin to decrease. This comes as all eyes turn to Florence and where she will track.