*******Note that forecast and outlooks in this post are NOT the official forecast from the National Hurricane Center (NHC). They are my own detailed views on the Atlantic tropics based on current observations and latest computer model runs. As such do not make decisions based on my posts...consult news media...watches and warnings from your local weather office...and any evacuation orders issued by local governments to make the most informed and best decisions. Visit the NHC website hurricanes.gov (hurricanes dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.*********
...UPDATE...FRIDAY AUGUST 16 2024 10:55 AM EDT...
The following changes have occurred with Hurricane Ernesto within the last 24 hours:
(1) The hurricane has strengthened to a minimal category 2 hurricane overnight... currently achieving 100 mph maximum sustained winds. This is only a little stronger than my previous intensity forecast which called for 95 mph maximum sustained wind for the current timeframe.
(2) The hurricane is northeast of the previous forecast track... and the center is already going to cross 30N latitude shortly. This means preparations in Bermuda need to be rushed to preparation sooner... no later than this afternoon as weather conditions will deteriorate soon.
...THURSDAY AUGUST 15 2024 10:15 AM EDT...
See Hurricane Ernesto section below for information on impacts the storm is expected to bring across Bermuda and southeastern Canada in the days ahead as it roams generally northward across the western Atlantic. Further east... monitoring tropical waves of low pressure following behind Ernesto as follows:
(1) Recent NHC TAFB surface analyses confirm the east-west elongated tropical wave of low pressure that has been moving into the central tropical Atlantic from the eastern Atlantic has split into two waves... which as of 0600Z this morning were analyzed to be at 39W and 52.5W longitude. After briefly losing thunderstorm activity last evening... the western of the two waves has redeveloped thunderstorms near 12.5N-52.5W this morning as the nearby suppressing inverted upper trough is accelerating westward and away under the influence of Ernesto's outflow. However additional suppressing upper vorticity currently east of Ernesto is expected to be shoved southwest by the storm's outflow... and into the Caribbean as the wave also enters the eastern Caribbean in 48+ hours... therefore this wave is not forecast to develop.
(2) The large tropical wave of low pressure that was previously over far western Africa has now entered the eastern tropical Atlantic... and the associated thunderstorms squalls on the southeast side of the wave have been gradually reducing. The tropical wave is currently not forecast to develop as it ingests a large area of dry Saharan air to the northwest.
(3) Satellite imagery over Africa (https://www.goes.noaa.gov/FULLDISK/GMIR.JPG) shows a large tropical wave of low pressure over central Africa which is forecast to emerge into the Atlantic in about five days (early this upcoming week). Computer models also do not develop this wave as its forecast to stay far north enough to ingest dry air associated with the north Africa Sahara desert.
HURRICANE ERNESTO... The tropical storm that was previously over the northeastern Caribbean Islands has become the third hurricane of the 2024 Atlantic season as of 11 AM EDT yesterday... while it turned increasingly north into western Atlantic waters. The intensification process was gradual while running into some westerly shear associated with the weakening band of cut-off upper vorticity to the storm's north which helped to keep thunderstorms limited west of the storm's center... and into a band of dry Saharan air that was also to the north which helped keep the developing core of thunderstorms over Ernesto's center separated from the outer thunderstorm bands. Ernesto's satellite appearance has continuously improved this morning as the thunderstorm activity has become a solid instead of broken comma-shaped shield that is growing in size... an indication that the environmental dry Saharan air has been mixed out. In addition westerly shear over the storm is relaxing as the aforementioned band of upper vorticity is collapsing... and the northern outflow of the storm has an opportunity to be enhanced by the southerly flow ahead of the upper trough currently moving into the west Atlantic from eastern Canada. Therefore additional strengthening of Ernesto is anticipated in the next 24 hours... however I stop just short of calling for a category 2 as wind shear potentially increases again as early as 24 hours when the hurricane runs into the westerly flow on the south side of the upper trough. Between 24 and 48 hours Ernesto is then forecast to be dragged by the western Atlantic upper trough and associated surface ridge weakness... and during this time I forecast the storm to weaken from the trough's shear. The upper trough and surface weakness then leave behind Ernesto in the 48 to 72 hour window... with the blocking surface ridge induced by the western convergence zone of the departing upper trough merging with the Atlantic surface ridge... creating a solid wall to the east of Ernesto that deflects the northeast track of the storm into a straight north angle across Bermuda. During this time I show another round of intensification finally into category 2 status as the shear relaxes due to upper trough pulling away... and also as Ernesto is overspread by a warm core upper ridge (low shear and outflow environment) in the warm sector of the next surface frontal system/upper trough to approach from eastern North America. However the models have trended with the departed upper trough leaving behind more upper vorticity just west of Ernesto which could block the hurricane's southwestern outflow... thus my intensity projection for the 48 to 72 hour window is lowered a bit compared to the previous forecast. Some changes have occurred with the forecast beyond 72 hours as the models have trended with a less amplified jet stream pattern in Ernesto's environment that has the overhead 72-hour upper ridge already shift east and the approaching eastern North America upper trough already overspreading Ernesto with upper southwesterly flow as soon as 96 hours. This results in an earlier eastward turn after Ernesto strikes Bermuda... and also more westerly wind shear... thus my track forecast is shifted east for 96 hours while also calling for Ernesto to begin weakening instead of strengthening further. Transition into a non-tropical frontal cyclone is forecast to be complete by 120 hours as the storm moves into waters below 26 deg C. The frontal cyclone is likely to gradually decay on the updated forecast track as the early eastward turn keeps the storm away from the supportive eastern divergence zone of the eastern North America upper trough... albeit the weakening rate may be slowed if ex-Ernesto's surface northwest quadrant manages to pull down enough high-latitude cold air to generate its own supportive shortwave cool-core upper trough.
Regarding impact to land areas:
(1) The northeastern Caribbean Islands (Dominican Republic to the northern Lesser Antilles) and southeastern Bahamas should see coastal surf generated by Ernesto relax going forward as the hurricane continues north and away.
(2) As of this writing... Bermuda is now under a hurricane warning for expected hurricane-force winds with damage potential and strong coastal surf expected to arrive this weekend... especially as the core of the hurricane is expected to pass over or very close to the island. Preparations here for Ernesto should be completed no later than early Saturday.
(3) For southeastern Canada... the risk for direct impacts such as heavy rainfall and strong winds early this upcoming week has ended for further north areas such as Prince Edward Island... Labrador... and southeastern Quebec due to the longer-term shift in the forecast track which calls for an earlier eastward turn. However the updated track still allows for coastal surf to reach Nova Scotia and Newfoundland... with southeastern Newfoundland being overspread by heavy rain and strong winds. Interests in Nova Scotia should also watch for any shift back west in the long range forecast track which could bring the region closer to the forecast swath of gusty winds and heavy rainfall.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0600Z Aug 15)... 85 mph maximum sustained wind hurricane centered in the western Atlantic at 23.9N-69.1W
IOH 24 Hr Forecast (0600Z Aug 16)... 95 mph maximum sustained wind hurricane centered in the western Atlantic at 27.5N-68.5W
IOH 48 Hr Forecast (0600Z Aug 17)... 85 mph maximum sustained wind hurricane centered south of Bermuda at 30.5N-64.5W
IOH 72 Hr Forecast (0600Z Aug 18)... 100 mph maximum sustained wind hurricane centered northeast of Bermuda at 34N-64W
IOH 96 Hr Forecast (0600Z Aug 19)... 85 mph maximum sustained wind hurricane centered in the northwest Atlantic at 39N-61W
IOH 120 Hr Forecast (0600Z Aug 20)... Remnant frontal cyclone centered southeast of Newfoundland at 44N-51W
*****National Hurricane Center (hurricanes.gov) official forecast as of 5 AM EDT**************************
Peak Strength (1800Z Aug 16)... 115 mph maximum sustained wind major hurricane centered south-southwest of Bermuda at 29.3N-66.7W
Landfall (1800Z Aug 17)... 105 mph maximum sustained wind hurricane centered over Bermuda at 32.6N-65.4W
5-Day Position (0600Z Aug 20)... 75 mph maximum sustained wind remnant frontal cyclone centered just offshore of southeastern Newfoundland at 47N-52W
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Aug 14) CMC Model Run...
**For Hurricane Ernesto… the track gradually bends from its current northwest angle to a northeast angle with the center ending up just southeast of Bermuda at 60 hours and south of Newfoundland (41.5N-56W) by 126 hours… transitions into a slowly weakening remnant frontal low that accelerates east-northeast to 51N-31.5W by 168 hours
1200Z (Aug 14) ECMWF Model Run...
**For Hurricane Ernesto… the track gradually bends from its current northwest angle to a northeast angle with the center ending up just west of Bermuda at 72 hours… the track then deflects straight north followed by a return to a northeast track which brings the hurricane just offshore of Nova Scotia at 126 hours… the hurricane transitions into a still-strong remnant frontal cyclone whose center passes just offshore of southeast Newfoundland at 138 hours… frontal cyclone curves more east in track and reaches 53N-28.5W by 168 hours
**Vigorous tropical wave of low pressure currently emerging into the Atlantic from Africa passes over the Republic of Cabo Verde Islands at 60 hours as a broad tropical low… weakens back to a wave shortly thereafter with no development shown in the long range
**Vigorous tropical wave of low pressure emerges from western Africa at 120 hours and passes just north of the Republic of Cabo Verde Islands as a broad tropical low by 162 hours
1800Z (Aug 14) GFS Model Run...
**For Hurricane Ernesto… the track gradually bends from its current northwest angle to a northeast angle with the center ending up just over Bermuda at 66 hours… hurricane then continues north-northeast into the waters just offshore of Nova Scotia (41.5N-59W) at 114 hours… while curving east-northeast begins to gradually transition into a remnant non-tropical frontal cyclone that passes just offshore of southeastern Newfoundland at 129 hours… while in open North Atlantic the remnant cyclone loses identity to larger frontal cyclone to the north by 159 hours
**Vigorous tropical wave of low pressure currently emerging into the Atlantic from Africa passes over the Republic of Cabo Verde Islands at 66 hours as a broad tropical low… weakens back to a wave shortly thereafter with no development shown in the long range
**Vigorous tropical wave of low pressure emerges from Western Africa at an unusually far north location (Mauritania/Western Sahara border) at 117 hours… passes well north of the Republic of Cabo Verde Islands (along 21N latitude) at 144 hours… tropical low opens back to a wave near 20N-32W by 168 hours
1800Z (Aug 14) NAVGEM Model Run...
**For Hurricane Ernesto… the track gradually bends from its current northwest angle to a northeast angle with the center ending up just southeast of Bermuda at 66 hours and south of Newfoundland by 114 hours… accelerates east across the North Atlantic while gradually transitioning into a non-tropical frontal cyclone and reaches the northeast Atlantic at 49N-21W at 168 hours
**Vigorous tropical wave of low pressure currently emerging into the Atlantic from Africa passes over the southern Republic of Cabo Verde Islands at 60 hours as a broad tropical low… weakens back to a wave shortly thereafter with no development shown in the long range
**Rather expansive tropical low emerges from the coast of Mauritania into the eastern Atlantic by 168 hours
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