By Peter Vankevich and Connie Leinbach
For Ocracokers, it is time to start taking this hurricane seriously.
The island is saturated, and this could add to the loss of trees as well as cause more flooded land and road blockages. Additionally, be prepared that the ferry system will shut down once conditions become dangerous.
The first advisory has now been issued.
The National Hurricane Center of the National Weather Service clarifies the difference between a warning and a watch.
A warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.
A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.
Hurricane Joaquin Forecast Discussion
HURRICANE JOAQUIN DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL1120155 PM EDT WED SEP 30, 2015
There has been little change in the organization of Joaquin during the past several hours. While the hurricane continues to produce cloud tops colder than -80C in the eyewall, the eye has not become better defined since the last advisory. Satellite intensity estimates are 77 kt from both TAFB and SAB, so the advisory intensity is now 75 kt. The initial motion is 225/7.
The shortwave ridge causing this motion is expected to weaken during the next 24-48 hours as a strong deep-layer trough develops over the southeastern United States. Thus, a generally southwestward motion is expected for the next 36 hours or so, followed by a turn toward the north as the trough becomes the dominant steering mechanism.
There is an increased disagreement between the GFS, UKMET, Canadian, and NAVGEM models versus the ECMWF since the last advisory. The ECMWF has continued its forecast of showing a northeastward motion after 72 hours, taking Joaquin just west of Bermuda and out to sea.
The other models have all shifted their forecasts to the left and now call for landfall in the Carolinas and the mid-Atlantic states, followed by merger with the baroclinic trough. Given the shift in the non-ECMWF models, a major westward adjustment has been made to the forecast track at 96 and 120 hours, bringing the center of Joaquin near or over portions of the mid-Atlantic states.
Due to the use of the ECMWF in the consensus models, the new track lies near the various consensus models. However, it lies well to the east of the GFS and the other similar models. The NOAA G-IV jet is currently flying a synoptic surveillance mission, which, along with special rawinsonde launches, hopefully will reduce the spread of the guidance. There is little change to the intensity forecast philosophy since the last advisory.
Joaquin is expected to remain in an environment of moderate northeasterly vertical shear for the next 24-36 hours, possibly including strong winds seen at 400 mb in recent dropsondes from the G-IV aircraft. However, since it has been steadily strengthening in such an environment, there is no obvious reason to think it will stop doing so. After 36 hours, the hurricane is likely to move into an area of divergent southerly upper-level winds associated with the eastern U. S. trough. While there is uncertainty as to how much shear should occur, it is expected that additional intensification could occur through at least 48 hours.
Based on this, the intensity forecast calls for Joaquin to peak as a major hurricane in 48-72 hours, and it is possible it could be stronger than currently forecast. After 72 hours, increasing shear, cold air intrusion, and land interaction should cause weakening and the start of extratropical transition.
KEY MESSAGES: 1. Preparations to protect life and property within the warning areas in the Bahamas should be rushed to completion. 2. A significant adjustment to the forecast has been made this afternoon, and this shows an increased threat to the mid-Atlantic states and the Carolinas. However, confidence in the details of the forecast after 72 hours remains low, since we have one normally excellent model that keeps Joaquin far away from the United States east coast. The range of possible outcomes is still large, and includes the possibility of a major hurricane landfall in the Carolinas. 3.
Every effort is being made to provide the forecast models with as much data as possible. The NOAA G-IV jet has begun a series of missions in the storm environment, and the National Weather Service is launching extra balloon soundings. 4. Because landfall, if it occurs, is still more than three days away, it is too early to talk about specific wind, rain, or surge impacts from Joaquin in the United States. Even if Joaquin stays well out to sea, strong onshore winds will create minor to moderate coastal flooding along the coasts of the mid-Atlantic and northeastern states through the weekend. 5.
A hurricane watch for a portion of the U.S. coast could be required as early as Thursday evening. 6. Many areas of the eastern U.S. are currently experiencing heavy rains and gusty winds associated with a frontal system. This inclement weather is expected to continue over the next few days, which could complicate preparations for Joaquin should it head toward the coast, and greatly exacerbate the impacts from the hurricane.
Heavy rains are likely to continue over these areas even if the center of Joaquin stays out to sea.