top of page
Home: Text

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 

Home: Text
Home: Blog2
Search

MY 2024 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #60

Writer's picture: NCHurricane2009NCHurricane2009

Updated: Aug 6, 2024

*******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...TUESDAY AUGUST 6 2024 1:19 AM EDT...

The surface and upper air charts... which were not previously included in the initial release of this update... are now included.


...MONDAY AUGUST 5 2024 4:00 PM EDT...

See Tropical Storm Debby section below for more information on its forecast and expected impacts across the southeastern United States from Florida to the mid-Atlantic region in the days ahead. See area of interest #16 section below for information on the the tropical wave that has recently crossed the southern Lesser Antilles... interests across Jamaica... northern Nicaragua... Honduras... Belize... and the Yucatan peninsula of southeastern Mexico should also be watching this wave as it potentially encounters upper winds more conducive for its development.


Further east... satellite imagery over Africa suggests the African Easterly Jet and associated surface tropical waves of low pressure are positioned further north. This will likely make the waves prone to ingesting dry air from the north Africa Sahara desert as they later move southwestward into the eastern tropical Atlantic around the southeast side of the Atlantic surface ridge. None of the current computer model runs are developing these waves.


HURRICANE DEBBY (RECENTLY DOWNGRADED TO TROPICAL STORM DEBBY)... Satellite image of Hurricane Debby at landfall with northern Florida this morning... taken at 1105Z:

Overnight and before landfall with north Florida Debby attained a peak strength as a category 1 hurricane with 80 mph maximum sustained winds. A combination of westerly flow ahead of the upper vorticity band left behind by the eastern North America upper trough and Debby re-generating closer to its sheared-off thunderstorms caused the hurricane to make landfall this morning a little east of the previous forecast track... on the northwest coast of the Florida peninsula just southeast of Perry. As of this writing Debby is turning northeast into southeastern Georgia as a 65 mph maximum sustained wind tropical storm... and over the next 24 hours models agree the upper vorticity band is shaped into an upper vortex trapped between upper ridging to the east bolstered by Debby’s thunderstorm latent heat release and western US upper ridge... with Debby shown to be kicked east toward coastal Georgia by the southeast quadrant of the upper vortex. Dropping wind shear levels... the eastern divergence zone of the vortex... and approach toward the warm waters offshore of Georgia should help slow Debby’s weakening rate over land... which is why I show a 50 mph max wind tropical storm by 24 hours despite a one-day stretch over land. For the long range... the models are coming into better agreement with what the ECMWF has been showing since yesterday and my updated track... as well as the NHC's track... are being adjusted accordingly. Between 24 and 48 hours what is now the central US surface frontal low and supporting shortwave upper trough move into the Ohio Valley region and help to push the upper vortex and Debby eastward into the waters offshore of South Carolina... and noting my 48 hour forecast point is close to the South Carolina coast as the east side of the upper vortex may help to lift Debby north. Between 48 and 72 hours... upper winds over Debby potentially become more conducive for development than previously thought as recent model runs are trending with the latent heat relase of Debby's thunderstorms weakening the cool core upper vortex such that ventilating anticyclonic outflow covers the storm in all four of its quadrants. The motion of Debby during this time is expected to be northwestward into the Carolinas as the convergence zone on the back side of the departing shortwave upper trough flares up steering surface ridging to the north... with the storm also tracking towards the ridge weakness of a developing Great Lakes frontal low supported by an upper trough approaching from the US/Canada border region. I have raised my intensity forecast point for 48 hours while catching the beginning of the more favorable upper wind outlook... but because my 48-hour position is close to shore I move the storm inland across South Carolina early such that my 72-hour forecast point depicts a weakening tropical storm. Note that some of the recent model runs which have a more offshore track allow Debby to re-intensify into a hurricane in the 48 to 72 hour window before heading into the Carolinas... so we will have to be concerned about Debby's intensity if the storm indeed tracks more offshore. To close out the 5-day forecast period... a turn to the north then northeast across the inland areas of the Carolinas and Virginia... and toward offshore Atlantic waters... is shown in the flow ahead of the approaching Great Lakes frontal low and supporting upper trough. Noting that by day 5 Debby will be transitioning into a non-tropical frontal low supported by the eastern divergence zone of the upper trough.


Regarding impact to land areas:

(1) The central and northern parts of the Florida peninsula... and southeastern Georgia... will continue to be raked by tropical storm conditions (heavy rain with flooding potential... gusty winds and coastal surf with damage potential) for the remainder of today.

(2) I recommend preparations for tropical storm conditions (heavy rain with flooding potential... gusty winds and coastal surf with damage potential) continue across coastal and inland areas of South Carolina... with preparations wrapping up in the southern part of the state by late today as weather conditions will have deteriorated by early tomorow morning.

(3) Interests along coastal and inland areas of North Carolina... Virginia... southeastern Maryland... Delaware... and New Jersey should be monitoring the progress of Debby. For now it appears the most likely scenario is a less tropical version of Debby potentially re-strengthening over land while supported by the divergence zone of an incoming upper trough... which would also result in heavy rain... gusty winds... and coastal surf across this region by late this week and into the weekend.


The following are the strongest winds (in mph) at each of the following National Weather Service stations (weather.gov) recorded so far:

**Perry (northern FL)... sustained 30... gust 62... 6:35 AM EDT

**Tallahasee (eastern FL panhandle)... sustained 21... gust 36... 4:53 AM EDT

**Lake City (northern FL)... sustained 24... gust 40... 1:55 PM EDT

**Jacksonville (northeast FL)... sustained 33... gust 58... 8:53 AM EDT

**Palm Coast (northeast FL)... sustained 25... gust 33... 11:50 AM EDT

**Daytona Beach (northeast FL)... sustained 14... gust 37... 11:53 AM EDT

**Valdosta (south-central GA)... sustained 30... gust 55... 11:55 AM EDT

**Waycross (southeastern GA)... sustained 24... gust 35... 12:55 PM EDT

**Vidalia (east-central GA)... sustained 21... gust 26... 12:55 PM EDT

**Hinesville (east-central GA toward coast)... sustained 20... gust 24... 1:55 PM EDT

**Savannah (northern coastal GA)... sustained 15... 8:55 AM EDT

**Brunswick (southern coastal GA)... sustained 31... gust 43... 1:35 PM EDT

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

0 Hr Position (1200Z Aug 5)... 70 mph maximum sustained wind tropical storm centered just south of the Florida/Georgia border at 30.2N-83.2W

IOH 24 Hr Forecast (1200Z Aug 6)... 50 mph maximum sustained wind tropical storm centered just inland of the northern part of the Georgia coast at 31.5N-81.5W

IOH 48 Hr Forecast (1200Z Aug 7)... 60 mph maximum sustained wind tropical storm centered just offshore of South Carolina at 32N-79.8W

IOH 72 Hr Forecast (1200Z Aug 8)... 50 mph maximum sustained wind tropical storm centered over central South Carolina at 33N-80.8W

IOH 96 Hr Forecast (1200Z Aug 9)... 35 mph maximum sustained wind tropical depression centered just south of the western part of the North Carolina/South Carolina border at 34.8N-81W

IOH 120 Hr Forecast (1200Z Aug 10)... Remnant frontal low centered just inland of the Virginia coast at 37.5N-76.5W

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

Landfall (1200Z Aug 8)... 60 mph maximum sustained wind tropical storm centered making landfall on the northeastern South Carolina coast at 33N-79W

5-Day Position (1200Z Aug 10)... 35 mph maximum sustained tropical depression centered just inland of the Virginia coast at 37.4N-76.9W


AREA OF INTEREST #16... The central Atlantic tropical wave of low pressure now crossing the southern Lesser Antilles into the eastern Caribbean Sea has become less organized... with all bands on thunderstorms now west of the maximum area of spin. It appears dry Saharan air has weakened the tropical wave for now... eating away at short-term chances of tropical cyclone formation. For the forecast track of this area of interest... I previously had a gradually northward curve toward Debby's surface ridge weakness also bolstered by shorter-term gravitation toward the southeastern divergence zone of the southward-sagging western Atlatnic upper vortex. My updated forecast track is now adjusted southward as there are more indications that Debby and the associated surface ridge weakness will move northward with time... increasing the probability that the surface tropical wave simply continues west-northwest through day 5 under the influence of the North American surface ridge that will be building behind the frontal system that absorbs Debby. In addition recent model runs have converged on the wave possibly developing further south toward Central America due to the latest upper wind outlook which is covered in the next paragraph.


The upper wind outlook in the short-term has not changed with the western Atlantic upper vortex sagging south under the influence of Debby's anticyclonic outflow... which for the next 48 hours increases outflow suppression and westerly wind shear on the north side of the tropical wave... this explains my low 10% odds of tropical cyclone formation during that time. For the longer term... the upper wind outlook has changed as models are trending with a stronger upper anticyclone remaining over the storm in the 48 to 72 hour window (see Debby discussion above for more details)... which keeps the western Atlantic upper vortex suppressed south toward this tropical wave and even forces some of the upper vorticity southward into a band across the central Caribbean. Around 72 hours today's model runs want to develop this tropical wave toward Central America (northern Nicaragua and Honduras) in a pattern of divergent upper easterlies between the west side of the Caribbean upper vorticity band and the ongoing current Gulf of Mexico upper anticyclone. However I keep odds of development at a low 10% during this timeframe as easterly shear may also be disruptive for development... and do not show a track as far south as Central America as the area of upper divergence is broad and can also aid in development further north as well. I begin to raise odds of development above 10% by days 4 and 5 as the tropical wave begins to move toward the core of the Gulf of Mexico anticyclone where shear is less... and if the current forecast holds I will be trimming odds of development even higher (in future updates) as this system enters the core area of the upper anticyclone in the long range.


Given the latest outlook... interests in Jamaica... northern Nicaragua... Honduras... Belize... and the Yucatan peninsula of southeastern Mexico should monitor the progress of this area of interest in the days ahead.

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

IOH 24 Hr Outlook (1200Z Aug 6)... 10% chance of tropical cyclone formation (eastern Caribbean Sea near 13N-66W)

IOH 48 Hr Outlook (1200Z Aug 7)... 10% chance of tropical cyclone formation (central Caribbean Sea near 14N-71.2W)

IOH 72 Hr Outlook (1200Z Aug 8)... 10% chance of tropical cyclone formation (south-southeast of Jamaica near 15.2N-76.5W)

IOH 96 Hr Outlook (1200Z Aug 9)... 20% chance of tropical cyclone formation (south of the Cayman Islands near 16.2N-81W)

IOH 120 Hr Outlook (1200Z Aug 10)... 20% chance of tropical cyclone formation (offshore of the southern Yucatan peninsula near 17.5N-86W)

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

Formation chance through 48 hours... 10%

Formation chance through 7 days... 30%


...COMPUTER MODEL SUMMARY...

Source...Tropical Tidbits models page (https://www.tropicaltidbits.com/analysis/models/).


0000Z (Aug 5) CMC Model Run...

**For Hurricane Debby... pulled east across south Georgia by a cut-off upper vortex left behind by eastern North America upper trough and reaches the SE US coast at the GA/SC border by 48 hours as a tropical storm... the tropical storm subsequently arcs northward around east side of upper vortex which takes it northeast into the waters offshore of South Carolina followed by a landfall on the northeast coast of South Carolina by 90 hours... while moving across eastern North Carolina... southeastern Virginia... Delmarva peninsula... and into the waters just offshore of New Jersey through 126 hours transitions into a remnant frontal low supported by upper trough approaching from US/Canada border region... frontal low center passes just offshore of Massachusetts at 132 hours then just offshore of Nova Scotia and Newfoundland through 156 hours... remnant frontal low then zooms east-northeast into the open north-central Atlantic and reaches 49.5N-40W by 168 hours

**For area of interest #16... develops into a tropical low offshore of Nicaragua near 12.5N-81W at 78 hours... tropical low passes northwestward over northeastern Nicaragua and eastern Honduras through 102 hours then proceeds into Belize at 114 hours... after crossing the southern Yucatan peninsula the tropical low enters the eastern Bay of Campeche through 132 hours... tropical low continues west-northwest toward the Veracruz/Tamaulipas border through 168 hours


0000Z (Aug 5) ECMWF Model Run...

**For Hurricane Debby... pulled east across south Georgia by a cut-off upper vortex left behind by eastern North America upper trough and reaches the Georgia coast by 36 hours as a tropical storm... subsequently frontal low approaching from the Ohio Valley region pushes Debby northeastward into the waters offshore of South Carolina through 78 hours after which time it loses its identity to Debby... with Debby re-intensifying into a hurricane as its thunderstorm latent heat release weakens the nearby cut-off upper vortex and its associated outflow disruption... while moving toward surface ridge weakness associated with frontal low developing toward the Great Lakes region the hurricane moves north-northwest and makes landfall just southwest of the NC/SC border at 96 hours... through 117 hours continues northward into central North Carolina while weakening into a tropical storm that begins to transition into a non-tropical frontal low supported by the upper trough that was previously supporting the Great Lakes frontal low (the frontal low loses its identity to Debby)... the remnant frontal low turns northeast across southeastern Virginia... Delmarva peninsula... and into the waters just offshore of New Jersey through 141 hours... frontal low center passes just offshore of Massachusetts at 151 hours and makes landfall over eastern Nova Scotia by 168 hours

**For area of interest #16... develops into a tropical low just offshore of Nicaragua at 84 hours then shortly thereafter weakens back to a wave while continuing into Nicaragua and Honduras... no development shown thereafter


0600Z (Aug 5) GFS Model Run...

**For Hurricane Debby... pulled east across south Georgia by a cut-off upper vortex left behind by eastern North America upper trough and reaches the Georgia coast by 36 hours as a tropical storm... the strength of the Gulf of Mexico upper ridge pushes the upper vortex and Debby into an east-southeast drift into the waters offshore of Georgia through 66 hours... once the upper vortex dissipates from Debby's thunderstorm latent heat release the tropical storm retrogrades west-northwest back into the Georgia coast through 78 hours while moving toward the ridge weakness associated with a developing Great Lakes frontal low... subsequently turns northwest into inland central Georgia through 102 hours as a weakening tropical storm... through 126 hours reverses to an east-northeast course across inland areas of the Carolinas while merging with surface cold front driven by Great Lakes/eastern Canada frontal low... as a rather elongated remnant frontal low ex-Debby continues across southeastern Virginia... the Delmarva peninsula... and into offshore waters through 138 hours... remnant frontal low then zooms northeast into Nova Scotia by 156 hours... remnant frontal low finally loses its identity along the front while moving across the Gulf of St Lawrence by 168 hours

**For area of interest #16... develops into a broad tropical low east of Nicaragua near 12N-81W at 78 hours... tropical low then turns northwest across northeast Nicaragua and eastern Honduras through 108 hours and then into the east coast of the Yucatan peninsula by 126 hours... tropical low continues northwest into the Gulf of Mexico from the northwestern Yucatan through 168 hours


0600Z (Aug 5) NAVGEM Model Run...

**For Hurricane Debby... turns east into the coast of Georgia by 36 hours after weakening to a tropical storm and then northeast into the waters offshore of South Carolina through 72 hours while re-gaining hurricane strength... hurricane turns north into northeastern South Carolina through 96 hours then turns north-northeast across central North Carolina through 114 hours as an inland weakening tropical storm... through 132 hours transitions into a remnant frontal cyclone that moves northeast across southeastern Virginia... the Delmarva peninsula... and into the waters offshore of New Jersey... remnant frontal cyclone passes just offshore of Massachusetts just after 138 hours and is centered midway between Cape Cod Massachusetts and Nova Scotia by 144 hours

**For area of interest #16... breifly develops into a broad tropical low east of Nicaragua at 96 hours after which time no development shown

19 views0 comments

Recent Posts

See All

Comments


bottom of page