*******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.*********
...THURSDAY NOVEMBER 14 2024 9:30 PM EDT...
Even though it is now mid-November... the Atlantic tropics still are active while monitoring two concurrent systems:
(1) Tropical Storm Sara has formed in the Caribbean and will bring impacts primarily to Honduras and Belize... see Sara section below for details.
(2) Some chance of subtropical development remains in the far eastern Atlantic in the vicinity of the Canary Islands and Azores... see area of interest #50 section below for details.
TROPICAL DEPRESSION NINETEEN (RECENTLY UPGRADED TO TROPICAL STORM SARA)... More recent infrared satellite image of Tropical Storm Sara taken at 0000Z:
Note the following forecast discussion was generated at 1200Z earlier today… however not much has changed since then. The prior central Caribbean tropical low was upgraded by the NHC to potential tropical cyclone (PTC) nineteen yesterday afternoon in order to raise tropical storm advisories (watches/ warnings) for parts of Central America early… in anticipation that it would eventually become a tropical storm. At the time the PTC featured a spin south of Jamaica and a secondary spin to the northwest. Long-term satellite animation covering the last 24 hours… in addition to the CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=)… shows the secondary northwestern spin was flung west-southwest toward eastern Honduras by the primary southern spin. Then through this morning the northwestern spin quickly became the dominant which was confirmed with a satellite scan of winds… and PTC nineteen became upgraded to tropical depression nineteen by 4 AM EDT. Aircraft recon data and an improved satellite appearance were grounds to upgrade the depression to Tropical Storm Sara by 1 PM EDT. The consolidation to the northwest has shifted the overall forecast track west as their is less of a chance of Sara stalling as the more west initial position moreso aligns the tropical storm with a eastern /central US deep-layer ridge that builds during the forecast period. However expecting Sara to almost stall near 84W longitude in the next 24 hours as the current north-central US upper trough is eroding the current east US coast steering surface ridge. In the next 48 hours Sara has more of a chance to strengthen than the previous forecast as the initial position is more south (toward 15.7N latitude instead of my previous forecast of 16.5N) which keeps it further from the shearing upper westerlies to be induced by the passing north-central US upper trough. However I do not forecast brisk intensification into a hurricane as Sara lacks an organized inner core on satellite pictures as of this writing… and as the deep-layer ridge pushes some of the west Atlantic upper vorticity southwest toward Sara which will begin to shear it at 48 hours. Because Sara’s forecast track has shifted west as noted above… the incoming upper vorticity no longer has a chance to dig west of Sara… instead Sara’s warm core upper outflow will now tend to deflect the upper vorticity southeast and eventually away… but not before imparting northwesterly shear across Sara in the 48 to 72 hour window. The west track around the deep-layer ridge may tend to be slowed by the counteracting upper northwesterlies… especially as Sara is near has its peak strength/ tallest structure toward 48 hours… thus I show some south deflection of the track into the NW coast of Honduras by 72 hours due to the northerly component of the upper winds. The NW shear causes me to lower Sara’s intensity projection from the peak at 72 hours. For the conclusion of the 5-day forecast… a relaxation in the shear is expected as the upper vorticity moves away… and Sara continues increasingly northwest in track while rounding the southwest side of the deep-layer ridge. On this track… Sara may re-strengthen in the relaxed shear environment in the 72 to 84 hour window… after which time landfall with Belize weakens Sara.
As of this writing bands of heavy rainfall cover the Cayman Islands… Belize… southeastern Yucatan peninsula… northeastern Guatemala… and Honduras… and this area could continue to see heavy rain in the next 24 hours. By 48 hours rainfall ends for Belize… southeastern Yucatan peninsula… and northeastern Guatemala as wind shear develops… with rainfall still continuing for Honduras. By 72 hours the northerly component of wind shear pushes the heavy rainfall south from Honduras and into Nicaragua and El Salvador… with the rainfall then transferring northwest across Belize… northern Guatemala… and the Yucatan by days 4 and 5. Honduras looks to have the highest rainfall totals while in the heavy rainfall area for 72 hours… the risk of life-threatening flash flooding and mudslides is highest here.
Gusty winds and coastal surf are expected for the northern Honduras coast in the next 72 hours… finally transferring to the Belize coast by 84 hours.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (1200Z Nov 14)... 35 mph maximum sustained wind tropical depression centered just offshore of eastern Honduras at 15.7N-82.6W
IOH 24 Hr Forecast (1200Z Nov 15)... 50 mph maximum sustained wind tropical storm centered just offshore of eastern Honduras at 15.7N-83.8W
IOH 48 Hr Forecast (1200Z Nov 16)... 60 mph maximum sustained wind tropical storm centered just offshore of north-central Honduras at 15.7N-86W
IOH 72 Hr Forecast (1200Z Nov 17)... 45 mph maximum sustained wind tropical storm centered on the northwest coast of Honduras at 14.8N-87.8W
IOH 96 Hr Forecast (1200Z Nov 18)... 35 mph maximum sustained wind tropical depression centered inland over the Belize/ Guatemala border at 16.8N-89W
IOH 120 Hr Forecast (1200Z Nov 19)… Remnant trough located on the west coast of the Yucatan peninsula near 20N-90.5W
*****National Hurricane Center (hurricanes.gov) official forecast as of 4 PM EDT*************************
Peak Strength (1800Z Nov 15)… 50 mph maximum sustained wind tropical storm centered just offshore of Honduras at 16.1N-85.5W
4-Day Position (1800Z Nov 18)… 30 mph maximum sustained wind dissipating remnant low centered over the western Yucatan peninsula at 19.3N-90.8W
AREA OF INTEREST #50... A deep-layer cyclone has materialized in the far eastern Atlantic to the north of the Canary Islands as the westward retrograding upper vortex from
the Iberia peninsula has pulled in the surface cyclone it generated with its southeastern divergence zone. Even though much of its 5-day forecast track is over waters below 26 deg C… the temps of the upper vortex are rather cold (200 mb heights below 1176 dekameters) which is helping to generate an increase in showers and thunderstorms in the circulation… therefore monitoring this feature for possible subtropical development. Due to the increase in activity and 0600Z GFS model run in the model summary section below which more explicitly showed a tropical-like core to the surface circulation… I have increased my peak odds of subtropical development to 30%. This system is expected to drift west for another 24 hours under the influence of the current NE Atlantic deep-layer ridge… then stall through 48 hours while waiting for a new warm core deep-layer ridge to develop in the north-central Atlantic (in the warm sector of the current western Atlantic frontal system). During the short-term the latest model runs keep the deep-layer cyclone more isolated from the passing upper trough fragment now moving toward southern Greenland (the fragment is a north fracture of the current west Atlantic upper trough)… which helps keep the deep-layer cyclone stalled instead of allowing the system to drift back east… thus the overall long-range forecast track has shifted west. Once the north-central Atlantic deep-layer ridge develops… it will help push the deep-layer cyclone south in the long range. During this time the upper layer of the cyclone decouples with the surface layer while gravitating more east toward a high-latitude upper trough fragment that slips down the east side of the deep-layer ridge (this fragment originates from the broth fracture of the current north-central US upper trough). This places the surface cyclone under the suppressive convergent west side of the upper layer… and the surface cyclone weakens toward day 5. Thus I trim developments odds from the peak to 0% in the 72 to 120 hour timeframe.
Given the west shift in the forecast track… the Canary Islands are less likely to see direct impacts from this system. However the Canary Islands and Azores are still due for coastal surf from this system regardless of subtropical status or not.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
IOH 24 Hr Outlook (1800Z Nov 14)... 30% chance of subtropical cyclone formation (north-northwest of Madeira near 36.5N-18W)
IOH 48 Hr Outlook (1800Z Nov 15)… 30% chance of subtropical cyclone formation (north-northwest of Madeira near 36.5N18W)
IOH 72 Hr Outlook (1800Z Nov 16)… 30% chance of subtropical cyclone formation (between the Azores and Canary Islands near 35N-21.5W)
IOH 96 Hr Outlook (1800Z Nov 17)… 10% chance of subtropical cyclone formation (west of the Canary Islands near 32N-23W)
IOH 120 Hr Outlook (1800Z Nov 18)… 0% chance of subtropical cyclone formation (west of the southern Canary Islands near 29N-23W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 7 PM EDT*************************
Not in the official outlook
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
0000Z (Nov 14) CMC Model Run...
**For tropical depression nineteen... slides west-southwest then west across north coast of Honduras through 42 hours... becomes quasi-stationary over the coast of north-central Honduras through 72 hours... proceeds west-northwest afterwards and makes landfall in Belize at 102 hours... inland remnant low slides west-northwest and degenerates into a trough over the southwestern Yucatan peninsula at 114 hours... through 126 hours the remnant trough loses identity to tail end cold front that reaches the southwestern Gulf of Mexico
**For area of interest #50... deep-layer cyclone materializes north-northeast of the Canary Islands through 24 hours... makes once complete counter-clockwise loop at this location through 54 hours.... while undergoing a larger radius second counter-clockwise arc begins to weaken with the arc taking the system west-northwest of the Canary Islands through 96 hours... weakens to a remnant trough southwest of the Canary Islands by 138 hours and dissipates shortly thereafter
0000Z (Nov 14) ECMWF Model Run...
**For tropical depression nineteen... slides west-southwest then west across north coast of Honduras through 36 hours while strengthening into a tropical storm... becomes quasi-stationary over the coast of north-central Honduras through 78 hours while weakening back to a tropical depression... the depression proceeds west-northwest into Belize through 102 hours... inland remnant low then continues west-northwest and enters the eastern Bay of Campeche by 120 hours while degenerating further to a trough... remnant low/trough then proceeds north-northeast across the central Gulf of Mexico in the flow ahead of a cold front that enters the southwest Gulf... remnant low/trough reaches waters offshore of the western Florida panhandle by 168 hours
**For area of interest #50... deep-layer cyclone materializes northeast of the Canary Islands through 24 hours... through 48 hours makes a counter-clockwise arc to a position just north of Madeira... while weakening proceeds southwest then south into the waters west of the Canary Islands through 114 hours... weakens to a remnant trough southwest of the Canary Islands by 138 hours which dissipates shortly thereafter
0600Z (Nov 14) GFS Model Run...
**For tropical depression nineteen... slides west-southwest then west across north coast of Honduras through 27 hours while strengthening into a tropical storm... becomes quasi-stationary over the coast of north-central Honduras through 51 hours while weakening back to a tropical depression... while weakening further to a remnant low continues west-northwest into Belize by 84 hours... the inland remnant low continues west-northwest while degenerating further to a trough which enters the eastern Bay of Campeche by 117 hours... the remnant trough re-strengthens to a remnant low while moving north-northeast across the central Gulf of Mexico in the flow ahead of a cold front that enters the southwest Gulf... remnant low makes landfall over the northern Florida peninsula by 162 hours then loses identity over southeast Georgia by 168 hours while merging with the incoming cold front from the west
**For area of interest #50... possible subtropical cyclone formation suggested north-northeast of the Canary Islands and near 35.5N-15W by 12 hours... the possible subtropical cyclone then makes one complete counter-clockwise loop in the region through 45 hours... while undergoing a second larger-radius counter-clockwise arc moves into the waters the possible subtropical cyclone reaches the waters midway between the Azores and Canary Islands by 87 hours... the possible subtropical cyclone weakens to a remnant low while diving south into the waters west of the Canary Islands through 117 hours... remnant low dissipates southwest of the Canary Islands by 156 hours
0600Z (Nov 14) NAVGEM Model Run...
**For tropical depression nineteen... slides west-southwest then west across north coast of Honduras through 36 hours while strengthening into a tropical storm... becomes quasi-stationary over the coast of north-central Honduras through 66 hours while holding tropical storm strength... subsequently moves west-northwest with the tropical storm making landfall on the coast of Belize by 90 hours... while slowly weakening the tropical storm proceeds across the southwestern Yucatan peninsula and into the eastern Bay of Campeche by 108 hours... while curving north then east-northeast into the east-central Gulf of Mexico gains hurricane strength by 168 hours
***For area of interest #50... deep-layer cyclone materializes north-northeast of the Canary Islands through 24 hours... makes one complete counter-clockwise loop at this location through 60 hours... then moves west to west-southwest into the waters between the Canary Islands and Azores through 84 hours... while turning south begins to weaken and reaches waters west of the Canary Islands by 132 hours... weakening remnant low positioned west of the southern Canary Islands by 168 hours
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