Extremely large hurricane Dorian moving NNW offshore the FL east coast
Dorian has undergone fairly significant structural changes over the last 24 hours as the wind field has greatly expanded and the eye has broadened. The central pressure continues to creep upward ... now to 964mb and the wind intensity has been lowered to 105mph.
Dorian is suffering from cold water upwelling under the large wind field which is bringing cold from below the surface upward and cooling the sea surface that the hurricane is trying to draw energy from. The function of this is a hurricane with a broad wind field and spread out pressure gradient.
Even as Dorian moves northward into warmer waters along the Gulf stream it will be hard for the hurricane to regain a well-defined inner core with such a large wind field.
Dorian is behaving very similar to hurricane Ike (2008). While Dorian is weaker than the last several days, its large size can result in far-reaching impacts and also has the potential to generate a large storm surge along the SE US coast.
Dorian is increasing forward speed this morning with a motion toward the NNW at 6mph and this motion will continue today with a turn toward the north and then NNE and NE Thursday and Friday and increase in forward speed. On this track, Dorian will approach the SC coast Thursday and over very near both the SC and NC coasts on Thursday and Friday. It remains possible that Dorian will make landfall in SC/NC.
As mentioned, regardless of an actual landfall, the large-sized wind field will certainly bring TS force winds to much of the SE US coast and likely hurricane conditions to SC and NC, even if the center remains offshore.
Dorian is in a steady state with only a slight rise in pressure over the last 12 hours. Hurricanes of this size usually do not have rapid changes in their intensity nor their core structure and Dorian is expected to remain between a 100-110mph hurricane as it moves toward the Carolinas over the next 48 hours.
Of more importance is the size of the wind field with TS force winds extending outward 175 miles from the center and hurricane-force winds 60 miles. This will prolong impacts along the coast.
A wind gust of 72mph was recorded overnight at Cape Canaveral and most recently a sustained wind of 46g59 was recorded at St Augustine FL.
TS force winds will continue to spread northward along the FL east coast today into coastal GA and then TS and hurricane conditions spreading into the Carolinas on Thursday and Friday.
Storm surge values of 4-7 feet above the ground will be possible along the SC and NC coasts Thursday and Friday including the significant potential for widespread flooding from storm surge in Charleston, SC. Values may reach as high as 8 ft above the ground near Myrtle Beach, SC.
Storm surge flooding will arrive well in advance of the onset of strong winds due to the large size of the hurricane. Rainfall amounts of 5-15 inches will be possible along the coastal Carolinas.
Fernand nearing landfall in MX
The overall cloud pattern and radar presentation of Fernand have degraded overnight with much of the deep convection having moved inland over N MX and S TX and the low-level center focusing on the eastern edge of the deep convection near the center.
Fernand has moved little faster than expected and the center will likely move inland later this morning. Gusty winds in squalls and heavy rainfall is spread inland across S TX today.
Fernand is moving toward the west slowly this moving and with high pressure building north of the tropical storm over TX this westward motion will continue with a landfall on the Mexican coast later this morning. After landfall, the remains of the system will move WNW into northern Mexico.
Easterly shear has prevented Fernand from any intensification overnight and most of the showers and thunderstorm activity are focused well W and NW of the center.
Fernand is out of time for any additional intensification and the system will cross the coast later this morning. Gusty winds of 40-50mph in squalls will be possible along the lower TX coast today especially along South Padre Island.
After landfall, Fernand will weaken and dissipate rather quickly although squalls will continue to move westward along portions of the Rio Grande into Thursday.