*******Note that forecasts 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.**********
...SATURDAY JULY 2 2022 2:49 AM EDT...
The vigorous tropical wave of low pressure now in the southern Caribbean Sea has become Tropical Storm Bonnie… which has already made landfall across Central America and is speeding into the eastern Pacific. See Bonnie section below for more information.
Elsewhere for the Atlantic basin… the following two areas of interest are being monitored by the National Hurricane Center for tropical cyclone formation:
(1) A tropical wave entering the eastern Caribbean Sea from the Lesser Antilles… see area of interest #10 section below for more details.
(2) A rapid-forming tropical low on the coast of South Carolina… see area of interest #11 section below for more details.
New to this site this year... I will be sequentially numbering up areas of interest for possible Atlantic tropical development. In this scheme... will reset back to #1 at the start of next year (January 2023). The current areas of interest in this blog post are designated #10 and #11 as I designated the other nine of this year in previous birdseye view posts on the home page. This scheme is to reduce confusion as Atlantic tropical activity increases during the peak of the hurricane season... when multiple simultaneous areas of interest begin and end which previously required shuffling around the area of interest numbers from update to update.
TROPICAL STORM BONNIE… Earlier on Friday while approaching the Nicaragua/Costa Rica border region of Central America… the vigorous and well-organized tropical wave of low pressure in the southern Caribbean Sea finally consolidated into the second tropical storm of the 2022 Atlantic Hurricane Season… Bonnie. As of 11 PM EDT after intensifying to 50 mph maximum sustained winds… the center of Bonnie made landfall on the Nicaragua/Costa Rica border region. The landfall has occurred sooner than I previously anticipated as the consolidation of the precursor wave’s broad circulation occurred to the south and west. The updated forecast track in the outlook below is adjusted accordingly. The initial part of the track forecast remains straightforward to the west at a continued quick speed. This is due to the strong deep-layer Atlantic ridge whose west side has been re-enforced by the current eastern US/west Atlantic surface ridge that has merged with it. The eastern US surface ridge will remain in place while supported by the southwestern convergence zone an upper vortex currently dropping southeast across central and eastern Canada. Once in the eastern Pacific… the end of the 5-day (120 hour) forecast track has a slow down and increase in northward angle as this system finally reaches the west end of the steering eastern US/west Atlantic ridge. However a sharp north angle is not shown in the models as this system is expected to be a strong tropical cyclone by days 3 to 4… tall enough to be influenced by an upper ridge cell expected to be over southwestern Mexico. This upper ridge cell by day 5 is shown to erode away as the upper vorticity currently near Baja California… Texas… and western Cuba team up by merging and retrograding southwest. However another upper ridge cell centered near 20N-120W is expected to persist… and even buckle the track of Bonnie more westward by day 5.
The intensity forecast is a balance between the fact that conditions for development are favorable with Bonnie expected to stay below tropical upper ridging with low shear and upper outflow... and the fact this system will continue moving rapidly which will make it initially challenging for this system to recover a closed circulation in the eastern Pacific in the event the land interaction with Central America significantly disrupts the currently well-defined closed circulation. Therefore a gradual strengthening rate is shown as Bonnie moves across the eastern Pacific. More rapid strengthening than shown in the forecast below is possible from 72 to 120 hours as Bonnie slows down… however waiting to see how well-established Bonnie will be in the eastern Pacific before projecting a more rapid strengthening rate. Note that Bonnie is expected to keep its tropical cyclone status and hence its name while quickly crossing a narrow part of Central America… which is why I will continue to forecast it as it lives on in the eastern Pacific.
With this forecast...the following impacts to land areas are anticipated:
(1) Tropical storm conditions (gusty winds and coastal surf) for southern Nicaragua and northern Costa Rica through tomorrow morning. Heavy rainfall is expected across all of Nicaragua and Costa Rica… making flash flooding another possible hazard.
(2) Once in the eastern Pacific... Bonnie is expected to strengthen which would induce coastal sea swells for the south coasts of Mexico and Guatemala next week. Sea swells are also possible for the coast of El Salvador if Bonnie recovers more quickly than currently forecast upon its entry into the eastern Pacific.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0000Z Jul 2)… 50 mph maximum sustained wind tropical storm making landfall at the Nicaragua/Costa Rica border at 10.9N-83.8W
IOH 24 Hr Forecast (0000Z Jul 3)… 40 mph maximum sustained wind tropical storm centered in the eastern Pacific offshore of Nicaragua and El Salvador at 11.5N-89W
IOH 48 Hr Forecast (0000Z Jul 4)… 60 mph maximum sustained wind tropical storm centered over the eastern Pacific at 12N-95W
IOH 72 Hr Forecast (0000Z Jul 5)… 75 mph maximum sustained wind hurricane centered over the eastern Pacific at 13.5N-99W
IOH 96 Hr Forecast (0000Z Jul 6)… 95 mph maximum sustained wind hurricane centered over the eastern Pacific at 14.5N-103W
IOH 120 Hr Forecast (0000Z Jul 7)… 105 mph maximum sustained wind hurricane centered over the eastern Pacific at 15N-107W
AREA OF INTEREST #10...The vigorous central Atlantic tropical wave of low pressure is now making its way across the Lesser Antilles and into the eastern Caribbean. Despite an increase in the wave’s thunderstorm activity… the wave is being undercut by wind shear induced by upper vorticity in the vicinity of the northern Lesser Antilles which is displacing the thunderstorms northeastward from the wave axis. None of the models forecast this wave to develop in this shear environment… and I plan this to be my final statement on this area of interest on this blog unless it continues to be mentioned in the NHC tropical weather outlook by my next update.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Jul 3)… 0% chance of tropical cyclone formation (eastern Caribbean Sea near 15N-68W)
AREA OF INTEREST #11… Throughout Friday and into the early morning hours of today… a tropical disturbance has taken shape on the coast of South Carolina and offshore waters with a remarkable pace in its organization. The disturbance has formed from the leftover tail end of the current cold front crossing the western Atlantic… and is already a full-fledged tropical surface low complete with an organized shield of thunderstorms on its east side supported by the outflow of the nearby upper ridge centered to the southwest. Because the tropical low is under the northeast side of the upper ridge instead of near its center/axis… it is also experiencing mid-latitude upper westerly shearing flow which is preventing thunderstorms on the west side of the tropical low.
The tropical low is currently sandwiched between an eastern US surface ridge and western Atlantic surface ridge. A narrow weakness between the two ridges is caused by the surface cold front being pushed by the current east Canada frontal low… therefore the tropical low is expected to continue northeast in this weakness and across the Carolina coast over the next 24 hours… and then merge with the incoming cold front by 48 hours while moving offshore. The merger with the front… cooler water temps just north of the Gulf Stream… and increased shear caused by a jet on the south side of the upper vortex also approaching from Canada… are expected to bring an end to tropical cyclone formation potential by 48 hours. However odds of development appear high for the next 24 hours. For 24 hours… I place 70% odds of tropical cyclone formation… a little higher than the NHC outlook as of this writing… as the tropical low shows no signs of giving up its organized thunderstorm mass.
The following are expected impacts to land areas from this disturbance:
(1) Heavy rainfall with isolated flash flooding on the coastal Carolinas… to slide from its current position in the vicinity of Charleston South Carolina and reach North Carolina as far north as the North Carolina/Virginia border in the next 24 hours
(2) Due to westerly shear… the strongest thunderstorms and tropical storm force gusts will be located east of the tropical low’s center and hence offshore. However the southeast gusty side of the tropical low may overspread the North Carolina coast from Cape Fear to Cape Hatteras in the next 24 hours.
(3) Choppy waters are possible from northeastern South Carolina to southeastern Maryland as this system passes by.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Jul 3)…70% chance of tropical cyclone formation (vicinity of Cape Fear North Carolina near 34N-78W)
IOH 48 Hr Outlook (0000Z Jul 4)… 0% chance of tropical cyclone formation (offshore of Maryland and Delaware near 37.5N-73.5W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Jul 1) CMC Model Run...
**For Tropical Storm Bonnie… enters eastern Pacific from Nicaragua/Costa Rica border at 24 hours… located at 17N-107.5W as a compact hurricane at 120 hours
**For area of interest #10... no development shown
**For area of interest #11… no development shown
1200Z (Jul 1) ECMWF Model Run...
** For Tropical Storm Bonnie…enters eastern Pacific from Nicaragua/Costa Rica border at 24 hours… located at 17.5N-107.5W as a compact hurricane at 120 hours
**For area of interest #10...no development shown
**For area of interest #11… no development shown
1800Z (Jul 1) GFS Model Run...
**For Tropical Storm Bonnie…enters eastern Pacific from Nicaragua/Costa Rica border at 18 hours… located at 15N-107W as a hurricane at 120 hours
**For area of interest #10... no development shown
**For area of interest #11… no development shown
1800Z (Jul 1) NAVGEM Model Run...
** For Tropical Storm Bonnie…enters eastern Pacific from Nicaragua/Costa Rica border at 24 hours… located at 16.5N-108W at 120 hours
**For area of interest #10...tropical wave briefly closes into an eastern Caribbean tropical low at 18 hours… opens back to a wave shortly thereafter with no development forecast.
**For area of interest #11… no development shown
**Vigorous tropical wave emerges from Western Africa and enters the eastern Atlantic at 96 hours… evolves into a tropical low located just southeast of the Republic of Cabo Verde Islands through 120 hours
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