Hurricane Joaquin: Ominous signs, but Northeast spared? Too soon to tell
First, before getting into details on Hurricane Joaquin, it is important to also mention that dangerous flooding is already underway in parts of New England, particularly in Maine where some areas have received as much as 7 inches of rain in the last two days. Jack Sillin made a good post yesterday on the short-term situation and that still applies. The situation will only exacerbate later this week as more rain falls from this frontal boundary as well as Joaquin or its remnants, regardless of the track. It is important to remember, Turn Around, Don’t Drown!!!
Now onto Joaquin. More models have latched onto the idea that the upper-level low over Georgia will move the storm northwest into a landfall along the North Carolina coast somewhere between the Virginia border and Cape Fear. However, the trend has been south and west in the past couple days, and some ensemble members even want to bring this ashore in South Carolina. It is important to note that some models still want to bring the storm farther north into the Northeast coast from Massachusetts to New Jersey, and even if we don’t get a direct hit, additional flooding rains, high winds and high surf are likely. Curiously, one model – a very reliable one – still wants to take Joaquin out to sea. It is not very likely in my opinion, but still a reasonable option.
Joaquin has been drifting southward in the past 24 hours, and is now located near the southeastern Bahamas. While it has done that, it strengthened into a hurricane last night and continues to intensify with an eye occasionally popping out. There hasn’t been an aircraft penetration since this morning, but I suspect the current intensity is near the upper end of Category 1 with approximately 90 mph sustained winds, and a minimum central pressure of 964 mb. A well-defined eyewall is visible on microwave imagery, which supports a stronger storm.
9 PM UPDATE: Joaquin is now a Category 3 hurricane with winds of 115 mph and a minimum central pressure of 951 mb, according to recent aircraft data and the NHC best track.
Possible Impact Scenarios
Strengthening is expected to continue, with Joaquin likely to become a Category 2 hurricane soon (if it isn’t already) and a Category 3 major hurricane by tonight or tomorrow. It is possible that Joaquin may even peak as a Category 4 hurricane by late this week as it takes advantage of very warm water near the Bahamas. Update: Joaquin reached Category 3 intensity this evening. Category 4 is likely by tomorrow, and I wouldn’t even rule out Category 5 intensity sometime late tomorrow or early Friday before weakening may begin. Once it moves north of about 30N latitude by later on Friday or Saturday, shear should increase, along with dry air and (possibly) cooler water temperatures, and weakening is possible. Less weakening is likely with more southerly solutions. As with yesterday, I will mention 5 possible scenarios – each with some model support – that I believe are possible. In addition, the impacts for the Northeast and Mid-Atlantic will be mentioned.
Scenario 1: Southeast direct hit (30% chance)
In this scenario, Joaquin is affected most greatly by the incoming trough and quickly turns from the north to the northwest. Yesterday this solution looked unlikely but there is some hints this may be possible as models have continued to shift south and west. The 12Z GFS is on the northern envelope of this possibility, but many ensembles bring Joaquin ashore along the lower North Carolina coast or even the South Carolina coast, between Charleston and Cape Lookout. The 12Z CMC also supports this possibility with landfall near or just south of Wilmington. The 12Z NAVGEM (not shown) goes even farther south, between Myrtle Beach and Charleston for landfall. Landfall would most likely be late Saturday or early Sunday, and with the Gulf Stream just offshore, weakening should be limited. A possible analog to this scenario is Fran in 1996, or even Hugo in 1989.
Northeast impacts: No direct impact. However, heavy rain should continue to be an issue, with additional flooding. Seas should be rough with rip currents, especially south of Cape Cod.
Mid-Atlantic impacts: Moderate direct impact. Tropical storm force winds are possible especially in the Delmarva and southern Virginia, depending on the size and exact track. Some storm surge flooding is also possible in those areas. Heavy rain is also likely with severe flooding possible especially in the mountains.
Scenario 2: Lower Mid-Atlantic direct hit (30% chance)
This was the preferred solution yesterday evening but many models have shifted southward. Nonetheless, the 12Z GFS still suggests that this is a possibility, and the 00Z GFS last night showed a very ominous situation. In this solution, Joaquin remains out to sea just long enough to be picked up by the trough between 33N and 35N latitude, then turns straight ashore, most likely early on Sunday, somewhere between Cape Lookout and south of Chincoteague. This would be the worst-case scenario for storm surge in the Chesapeake and Potomac regions, and would be catastrophic for Hampton Roads. The closest analogs to this scenario are Isabel in 2003 and the Chesapeake-Potomac Hurricane in 1933.
Northeast impacts: Minor direct impact. Some strong wind gusts are possible, along with coastal flooding, particularly south of New York City. However, it should not be as severe as with Sandy or Irene. Heavy rainfall again a major threat, especially indirect rainfall from the larger frontal boundary.
Mid-Atlantic impacts: Severe to catastrophic impact in southern regions, especially to coastal areas. Depending on the exact landfall location, hurricane force winds are possible near the center of the storm, along with very high storm surges and heavy rainfall from the storm as well as the indirect impact which may result in catastrophic inland flooding. The greatest storm surge threat would be in the Chesapeake and Potomac basins, as well as Delaware Bay. If landfall is just south of Hampton Roads, record flooding is likely there. Impacts lower further north but still very significant.
Scenario 3: Upper Mid-Atlantic direct hit (15% chance)
Most likely, the trough does not fully swing Joaquin around in this scenario. However, the ridge backs in eventually and the trough captures Joaquin later, north of Chincoteague to Brigantine. Landfall would likely be later on Sunday as a result. The NHC official forecast, which is a compromise solution, suggests this but it is not supported by any current model runs. However, many ensembles still support this. This would be the worst-case scenario for the Delaware Bay areas and (for wind at least) areas between DC and Philadelphia. This solution is most comparable to Sandy in 2012, although with a smaller, more tropical storm and more focused impacts.
Northeast impacts: Moderate to severe direct impacts, depending on the exact landfall point. Tropical storm force winds are possible in southern coastal areas and exposed regions, along with very heavy rainfall. Some storm surge threat will also exist in the New York City region, but not nearly as severe as Sandy.
Mid-Atlantic impacts: Severe to catastrophic impact in northern regions, especially to coastal areas. The greatest storm surge threat would likely be in Delaware Bay and on the New Jersey coastline, with hurricane force winds and very heavy rainfall. Significant winds should spread well inland as well through the DC and Baltimore regions with hurricane force gusts possible. However, the storm surge should be reduced there due to the Delmarva blocking water.
Scenario 4: Northeast direct hit (10% chance)
The probability of this scenario has definitely decreased, but it is not entirely out of the question (look at the image above). In this scenario, the trough would not capture it or it would only slightly tug it westward, but not enough to make landfall. However, the blocking ridge to the north would prevent Joaquin from moving out to sea, and instead the storm would make landfall (most likely late Sunday or early Monday) somewhere between Chatham, MA and Brigantine, NJ. This is likely a worst case scenario for New England and the New York City region, depending on landfall location. The most comparable storms would be Irene 2011 and Carol 1954.
Northeast impacts: Severe impacts. Major coastal and inland flooding would be likely with storm surges very high (albeit in a smaller area than Sandy). For NYC, the worst case would be a hit just to the south moving northwest or north-northwest (due to the smaller size). Tropical storm force winds would be likely in nearly all areas, with hurricane force winds possible in coastal and exposed areas. Major inland flooding – as bad as or worse than Irene – is also possible.
Mid-Atlantic impacts: Significant impacts still possible, although direct impacts should be less. The primary threat would be rainfall, although coastal areas may still see tropical storm force winds. Since the flow would be offshore, storm surge wouldn’t be a big issue.
Scenario 5: Out to sea (15% chance)
The European model – a very reliable model – continues to insist that Joaquin is going out to sea. In this solution, the trough cannot reach Joaquin and it either is trapped in the Bahamas, or uses the remnants of Ida (which may itself redevelop) as a trough with an escape route out to sea. A slower Joaquin would most likely result in this solution – which I think is unlikely but not unreasonable. There would be no direct impact with this solution, but flooding from the larger scale system is likely, and some of that could be very severe in itself. Bermuda would potentially face a dangerous hit from Joaquin, however.
Just because the models have mostly moved south and west does not mean we should let our guard down in the Northeast. The Mid-Atlantic and Southeast coasts should be especially vigilant since it is likely that Joaquin will still be a formidable hurricane – most likely Category 2 or 3 – if it makes landfall in those areas. However, there is still some potential for a direct Northeast hit, and also some chance that Joaquin goes out to sea. Regardless, VERY heavy rain – on top of the saturated ground that we already have had from this week’s rain – is likely for virtually all of the Northeast and Mid-Atlantic. In some places, the rainfall could be excessive – over a foot easily in total. The greatest totals should be in Virginia and North Carolina, where over 25 inches this week may not be out of the question.
Although this is a very fluid situation, the chance of a US landfall is much higher than it was 24 hours ago, with southern areas most preferred (i.e. from South Carolina to Virginia). But don’t assume the threat is decreasing in the Northeast – it isn’t! We should all be preparing for a potentially dangerous hurricane just in case the track changes. Best to be prepared, not scared. Stay safe.
(Personal note: I tend to get scared and nervous easily…that is how my body goes, even though it is definitely a bad idea!)
Forecaster Craig Ceecee