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BIRDSEYE VIEW POSTS

Since 2012 on the now retired Weather Underground blogs, I have been posting annotated "birdseye view" charts of the Atlantic basin, with a detailed explanation and forecasting that references the chart. From there you may know me as "NCHurricane2009." While I now do these "birdseye view" posts here, I will continue to do comments at Yale Climate Connections via Disqus where the former Weather Underground community has moved to. Feel free to reply to me there, at my Disqus feed at this link, or via e-mail at IOHurricanes@outlook.com 

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MY 2023 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #37

*******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.**********


...SATURDAY JULY 22 2023 9:04 PM EDT...

Recently-upgraded Hurricane Don is expected to continue northwestward into waters offshore of eastern Newfoundland... arriving there by tomorrow and into Monday. See Don section below for more information on the hurricane. Elsewhere... see area of interest #14 section below for an update on the current central Atlantic tropical low expected to cross the southern Lesser Antilles by Wednesday.


Note my forecasts below were generated at 1200Z earlier today. Not much has changed between then and the release time of this update.


HURRICANE DON... Satellite image of recently upgraded Hurricane Don as of 2050Z:

While continuing to anticyclonically curve around the periphery of the steering North Atlantic deep-layer ridge... Don has moved northwestward into the northwestern Atlantic and will soon curve northeast and east-northeast on a route offshore of eastern Newfoundland and into north-central Atlantic waters. Because Don is already a little east of my previous forecast track and the longer range model guidance has shifted east... my updated track is adjusted in that direction. While having reached a more favorable environment of 26 deg C waters... coupled with low shear and upper outflow beneath the southwest side of the deep-layer ridge... Don has acquired a strength of 65 mph maximum sustained winds which is the highest strength it has achieved in its lifecycle thus far. Going forward... Don should gradually weaken in the low shear environment and also lose tropical characteristics by 48 hours while moving across markedly cooler waters. Don has a chance to bring coastal surf to the eastern shores of Newfoundland tomorrow and into Monday.


Update as of 5 PM EDT... Don has strengthened further into the first hurricane of the 2023 Atlantic season while achieving an estimated 75 mph maximum sustained winds. I have increased my intensity forecast for 1200Z tomorrow morning to reflect this.

******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********

0 Hr Position (1200Z Jul 22)... 65 mph maximum sustained wind tropical storm centered at 39.1N-50.1W

IOH 24 Hr Forecast (1200Z Jul 23)... 60 mph maximmum sustained wind tropical storm losing tropical characteristics while centered at 43N-50W

IOH 48 Hr Forecast (1200Z Jul 24)... Remnant low centered in the North Atlantic at 47N-49W

******National Hurricane Center (hurricanes.gov) official forecast as of 11 AM EDT***************************

Loss of tropical cyclone status (0000Z Jul 24)... 40 mph maximum sustained wind non-tropical remnant cyclone centered east-southeast of Newfoundland at 46.1N-49.1W


AREA OF INTEREST #14... The tropical low pressure in the central tropical Atlantic has not developed further over the last day as its thunderstorm cluster struggles from dry Saharan air lurking to the north. Regarding forecast track... the tropical low is forecast to increasingly accelerate westward as the steering surface layer of the North Atlantic deep-layer ridge expands due to the convergence that will develop between the northern outflow of the regional tropical upper ridge and the south side of the deep-layer ridge’s upper layers. For the next 4 days this should result in a largely westward heading with little northward angle… with some increase in the north angle possible by day 5 once this system rounds the southwestern periphery of the steering surface layer of the deep-layer ridge. I have nudged the forecast track points northward due to the position of the tropical low relative to the previous forecast. Regarding odds of tropical cyclone formation... I agree with the NHC in recently lowering back down odds of development due to the anemic thunderstorm activity caused by the dry Saharan air and lackluster computer model support. For the long-term a wall of western Atlantic warm core upper ridging is expected to persist as upper vorticity will remain trapped over eastern North America and produced more surface frontal systems that will transport warm air northward across the western Atlantic. The western Atlantic wall of upper ridging may push a portion of the current suppressing central Atlantic upper vortex southwestward into the Caribbean and into the long-range track of this disturbance... this is why by day 5 I trim down development odds. Interests in the southern Lesser Antilles should remain aware of this system in the event it overcomes dry air and attempts to develop... which would result in impacts (gusty winds... heavy rains... and coastal surf) by Wednesday.

******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********

IOH 24 Hr Outlook (1200Z Jul 23)... 20% chance of tropical cyclone formation (central tropical Atlantic near 11.5N-45W)

IOH 48 Hr Outlook (1200Z Jul 24)... 40% chance of tropical cyclone formation (central tropical Atlantic near 12N-50W)

IOH 72 Hr Outlook (1200Z Jul 25)... 40% chance of tropical cyclone formation (east of the southern Lesser Antilles at 12.5N-55W)

IOH 96 Hr Outlook (1200Z Jul 26)... 40% chance of tropical cyclone formation (vicinity of Barbardos near 13N-60W)

IOH 120 Hr Outlook (1200Z Jul 27)... 30% chance of tropical cyclone formation (eastern Caribbean Sea near 14N-65W)

******National Hurricane Center (hurricanes.gov) official outlook as of 8 PM EDT*****************************

Formation chance through 48 hours...40%

Formation chance through 7 days (168 hours)...50%


...COMPUTER MODEL SUMMARY...

Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).


0000Z (Jul 22) CMC Model Run...

**For Tropical Storm Don... curves north-northwest and then northeast into cooler waters where it weakens to a remnant trough near 47.5N-37.5W at 72 hours

**For area of interest #14... no development shown


0000Z (Jul 22) ECMWF Model Run...

**Not available at above-mentioned source


0600Z (Jul 22) GFS Model Run...

**For Tropical Storm Don... curves north-northwest then east-northeast into cooler waters where it weakens to a remnant trough near 47.5N-34W at 72 hours

**For area of interest #14... no development shown


0600Z (Jul 22) NAVGEM Model Run...

**For Tropical Storm Don... curves north-northwest and then northeast into cooler waters where it weakens to a remnant trough near 49N-41W at 60 hours

**For area of interest #14... no development shown

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