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Hurricane Ian will stumble inland toward Virginia after its second landfall Friday, quickly devolving into a disheveled yet still somewhat dangerous version of its once Category 4 hurricane infamy.
The remnant circulation of Ian, which came ashore with 150 mph winds and house-swallowing storm surge in southwest Florida on Wednesday and is due for a second landfall in South Carolina on Friday as likely a lower-end hurricane, will bring a swath of rain, heavy at times, across Virginia Friday into early Saturday, with showery periods related to what’s left of Ian continuing off and on through the weekend and perhaps as late as Tuesday.
Most of Southwest and Southside Virginia are likely to see 2 to 4 inches of rain, and some spots could see more, especially along the Blue Ridge from Roanoke southward, where easterly components to surface winds will lift and condense moisture more efficiently. It appears, as of this Thursday evening writing, that the bulk of this rain will happen between noon Friday and mid-afternoon Saturday in Southside and Southwest Virginia.
There is some risk of flooding, especially anywhere heavier bands of rain can move over the same location repeatedly. Local details like that are not foreseeable beyond short-term radar detection, so monitor National Weather Service updates and local broadcast and Internet media for the latest.
A widespread major tropical-induced flooding episode akin to Agnes in 1972, Juan in 1985, or even Michael in 2018 appears to be unlikely for the commonwealth.
We go into Ian pretty dry. In fact, much of central and eastern Virginia, as far west as Lynchburg and almost to Danville, is considered to be in the light to moderate levels of drought by the U.S. Drought Monitor. Even farther west, though not in official drought, Roanoke has had only .09 inch of rain in the last 17 days.
It is NOT true that flooding can never follow dryness – it often does, when rain is sudden and torrential. But dry soils do require a little extra rainfall before they are saturated. This go-round, with periods of light to moderate rain interspersed with heavier squalls, that may make the difference between merely rising streams and flooding ones in many areas.
Some places near the lower end of the rainfall totals may even consider Ian a bringer of beneficial moisture.
Even more of a limitation for Ian being big trouble in Virginia is the atmospheric setup, one that makes fans of snowfall wish it were January.
The rules of the atmospheric playground are that high pressure systems are the bullies. High-pressure systems push hurricanes around, not vice-versa.
Strong high pressure in Canada is pressing a cool, dry air mass southward to meet Ian. This will eat at least some of Ian’s early moisture spreading northward and will tend to weaken Ian’s circulation as it moves against it inland.
Hurricane winds always weaken at landfall, as the storm is removed from its evaporative energy source of warm ocean water, but some atmospheric setups allow the hurricane’s winds to be absorbed into a low-pressure system and carry strongly far inland. This is not one of them.
Marginally tropical storm level winds above 39 mph (that’s sustained, not gusts) might make it as far inland as Charlotte or Greensboro – a far cry from what Category 4 Hugo did on a similar track in 1989, with near-hurricane force winds even into parts of Southwest Virginia.
Ian will be pumping lots of warm ocean moisture up and over the cool dome of air pushed southward, banked against the mountains. This is the part that makes winter fans drool – a similar pattern in January with a regular low-pressure system would unload tons of snow on Virginia.
But that big high also isn’t allowing Ian to move north or northeast rapidly like many tropical systems do after a Gulf of Southeast U.S. landfall. Instead, Ian’s center will drift a little northwest, possibly west, with weak steering currents to take it anywhere. Meanwhile, much of its mass of moisture will shear off to the north and east.
Ian will essentially split apart with a remnant weak circulation hanging around the Appalachians a few more days, spinning up some showers especially into the western part of the state. There is some risk of heavier storms forming in localized areas with this meandering ghost of Ian into early next week, but widespread flooding doesn’t look to be in the offing this time for Virginia.
Every tropical system making landfall carries some risk of spinning off tornadoes, as winds moving in different directions aloft produce shear that create spin. Lack of instability, with the cool air pumped southward from the high to the north, will, however, limit that potential considerably in Virginia.
As the remnant circulation drifts west or northwest, there may be some risk of tornadoes to the east and northeast of that center, where warmer southerly winds partially erode the cooler air mass to the north or create a boundary with it, and perhaps carry a bit more spin. This could eke into Southside but doesn’t seem a particularly high risk at this time.
There may be some 40+ mph wind gusts, especially on ridgetops and near the Virginia-North Carolina border, on Friday and Saturday in the pressure gradient between the low air pressure in Ian’s center and high pressure to the north.
But stronger winds aloft will have a hard time mixing to the surface through the cool surface wedge pressed from the north, and Ian’s inland weakening will reduce the gradient for surface winds pretty quickly.
Friday and Saturday certainly won’t feel very “tropical” even amid rain swept in by a storm that was born in the Caribbean – temperatures will be stuck in the 50s at most locations under the Cardinal News umbrella.
Neither hurricanes nor chilly damp days are strangers to Virginia in autumn.