12:45 PM | *Tropical Storm Gordon should make landfall late tonight in the north-central Gulf…Florence is now a hurricane and it is still a concern for the US east coast*
Paul Dorian
Tropical Storm Gordon could reach hurricane status before making landfall late tonight. Numerous recent lightning strikes near the inner core suggest further strengthening is possible in the near term. Courtesy lightningmaps.org, NOAA
Overview
The climatological peak of the Atlantic Basin tropical season comes in mid-September and this year is certainly holding true to form. There are currently three tropical systems to monitor and other systems are likely to form in coming days. Tropical Storm Gordon is heading towards the Mississippi/Louisiana border region and is likely to make landfall there late tonight. Florence has just reached hurricane status and it is moving on a WNW track out over the open central Atlantic. There is a chance that Florence gets "captured" by a eastward-moving trough this weekend; however, if it is left behind then the evolving pattern could become quite threatening for the US east coast. Yet another system trails Florence relatively close to Africa’s west coast and it will also likely become a concern in coming days.
Current sea surface temperature anomalies; courtesy NOAA, tropicaltidbits.com
Gordon
At 11am, Tropical Storm Gordon had max sustained winds of 65 mph and is moving northwesterly at 15 mph. Gordon should make landfall late tonight near the Mississippi/Louisiana border region and there is a chance that it reaches hurricane status (category 1) before that happens. In fact, lightning strikes have increased in recent hours near the inner core suggesting further intensification is possible just before Gordon makes landfall in the north-central region of the Gulf of Mexico. A strong storm surge is expected with the approach of Gordon and heavy rainfall amounts could exceed a foot in parts of the north-central Gulf region.
Once Gordon moves inland, it’ll tend to slow down and that could exacerbate flooding potential in the south-central US during the second half of the week. By late in the week, Gordon will begin to merge with a cool frontal system and turn northward towards the Midwest and then eventually to the northeast towards the northern part of New England. There could be a swath of heavy rain along its track later this week and into the weekend including perhaps in the northern Mid-Atlantic region.
Hurricane Florence is currently in an environment with some dry air (Saharan Desert), but it has still managed to intensify into hurricane (category 1) status in recent hours; courtesy University of Wisconsin, NOAA
Florence
Florence has just become the third hurricane of the Atlantic season with max sustained winds now at 75 mph and its movement is WNW at 12 mph. It is actually quite impressive that Florence has strengthened into hurricane status in recent hours given its current location over colder-than-normal water as well as its position in the midst of some dry (Saharan Desert) air. Once Florence gets beyond this somewhat hostile environment further intensification is likely.
An upper-level trough of low pressure over the north Atlantic this weekend could "capture" Florence and keep it safely away from the US east coast, but there is still a chance that it is "left behind"; courtesy NOAA, tropicaltidbits.com
Florence poses no threat to land through at least the upcoming weekend. Looking beyond the weekend, however, there are two possibilities with respect to its storm track. In one scenario, an eastward-moving trough likely to be over the north Atlantic Ocean this weekend, could “capture” Florence and pull it to the north Atlantic without ever posing a threat to the US east coast. In another scenario, however, Florence could be “left behind” by the trough and then the door will likely be open for a turn to the west and towards the US east coast as strong high pressure ridging will re-build over the north Atlantic following the passage of the trough.
The time period surrounding the arrival of Hurricane Andrew in August 1992 featured strong high pressure ridging at 500 mb (left) over SE Canada/north Atlantic and the latest forecast for early next week has a similar look (right); courtesy NOAA, tropicaltidbits.com
Some upper-level similarities to Hurricane Andrew
In August 1992, Hurricane Andrew pushed westward across the southwestern Atlantic and made landfall in southern Florida before moving out over the Gulf of Mexico. The upper air pattern in the days surrounding Andrew’s approach to Florida featured strong high pressure ridging over the north Atlantic – quite similar to what the setup could be next week following the passage of the eastward-moving trough.
Stay tuned…whether Florence gets “captured” by an upper-level trough is still an open and important question for all residents along the US east coast. Another system or two will likely follow Florence in coming days and they make take a "southern" route and heads towards the Caribbean Sea, Gulf of Mexico and/or Southeast US.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
Extended video discussion on the tropical threats: