11:15 AM (Tuesday) | *Hurricane Sally has slowed down to a crawl…two feet of rain possible in some spots next couple of days…wildfire smoke makes it all the way to the Mid-Atlantic/Northeast US*
Paul Dorian
Hurricane Sally remains a category 1 storm at mid-day as it slowly crawls towards the northern Gulf coastline. Images courtesy College of DuPage, NOAA
Overview
The Atlantic Basin remains full of tropical activity today with two hurricanes, two tropical storms and three other waves extending far and wide from the southwestern Gulf of Mexico to the west coast of Africa to the Northern Atlantic. Hurricane Sally remains over the warm waters of the northern Gulf of Mexico at mid-day and has slowed down to a crawl which will contribute to excessive amounts of rainfall over the next couple of days in the region from western part of Florida’s Panhandle to southeastern Mississippi.
In the Mid-Atlantic region, temperatures this morning dropped to the lowest levels of the season so far with many suburban locations along the I-95 corridor bottoming out in the 40’s. And while there is plenty of sunshine today to go along with the cool conditions, the sun is dimmed in many areas by an upper-level of smoke from the western wildfires. An even cooler air mass will arrive in the Mid-Atlantic region by the weekend with Saturday’s highs likely confined to the 60’s in the DC-to-Philly-to-NYC corridor – well below-normal for this time of year.
Hurricane Sally has slowed down to a crawl and this will result in excessive rainfall amounts over the nextcouple of days of up to two feet or so in the northern Gulf coastal region. Map courtesy NOAA/WPC
Hurricane Sally
Hurricane Sally has slowed down to a crawl with its latest movement measured at only 2 mph in a northwesterly direction and maximum sustained winds of 85 mph. The intensity level of Hurricane Sally has remained pretty steady in recent hours and there is no clearly defined “eye” with this category 1 storm. Two factors have been inhibiting intensification in recent hours including moderate westerly wind shear and upwelling beneath the slow moving system. Since Sally has grinded to a near halt, the churning of the water underneath its inner core has likely resulted in colder water from below to rise up to the sea surface (upwelling) and this lessens the chance for intensification.
The Atlantic Basin is full of activity at mid-month with two hurricanes, two tropical storms and three other waves (marked by “X”). Map courtesy NOAA/NHC
The system may begin a turn to the north later today and then to the northeast later tonight, but its slow motion is likely to continue for another couple of days. As a consequence of the slow movement, copious amounts of rain will fall in the northern Gulf coastal region extending from the western part of Florida’s Panhandle to southeastern Mississippi. In fact, some spots could see upwards of two feet of rain in this region over the next 48 hours or so. Hurricane Sally is likely to make landfall early tomorrow and then move slowly through the southeastern states of Alabama and Georgia before reaching the Carolinas at the end of the week.
A high-resolution forecast model depicts the extent of the smoke plume across the nation from the wildfires in the western states. In fact, sunshine is dimmed today as far away as the Mid-Atlantic region and Northeast US as a result of upper-level (15,000-20,000 feet) layer of smoke and it may be noticeable into tomorrow as well. Map courtesy NOAA
Mid-Atlantic/Northeast US
Strong high pressure is dominating the scene in the Mid-Atlantic and Northeast US and will continue to do so for another couple of days. This system brought some of the lowest temperatures so far this season in the overnight hours as some suburban locations dropped to the 40’s for the first time in months. And while there is plenty of sunshine today to go along with the cool conditions, the sun is dimmed in many areas by upper-level of smoke in upper-levels of the atmosphere that originated in the western US wildfires. The smoky look to the sky may continue into Wednesday as well resulting in much more orange in the sunsets and sunrises. An even cooler air mass will arrive in the Mid-Atlantic region by the weekend following the passage of a late week strong cold frontal system. In fact, Saturday’s highs are likely to be confined to the 60’s in the DC-to-Philly-to-NYC corridor – well below-normal for this time of year.
A very chilly air mass for mid-September will push into the Northeast US/Mid-Atlantic region this weekend with highs on Saturday likely confined to the 60’s in DC, Philly, NYC and Boston. Map courtesy NOAA, tropicaltidbits.com
In terms of rainfall from the remnants of Sally, there is still a chance for some decent rain to make it as far north as the I-95 corridor region on Thursday night and Friday as a strong cold front approaches from the northwest. It appears quite likely that some heavy rainfall will make it into southern Virginia and the southern part of the Delmarva Peninsula and it wouldn’t take much of a shift to bring it a little farther north. We’ll monitor this rain threat closely over the next couple of days as the slow movement of Sally opens the door somewhat for potential subtle changes in the overall upper air pattern along the eastern seaboard.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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