*******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.*********
...UPDATE...MONDAY OCTOBER 21 2024 10:30 PM EDT...
The surface and upper air charts valid for October 20 have been added below.
...SUNDAY OCTOBER 20 2024 1:20 AM EDT...
See Nadine and Oscar sections below for the pair of Atlantic basin tropical cyclones that roared to life on Saturday. Elsewhere… as noted in the Oscar discussion below... cut-off upper vorticity will persist in the western Atlantic for a few days. If the upper vorticity eventually evolves into a configuration with low enough westerly shear and high enough upper divergence on its east side... it could support a surface low pressure area with tropical characteristics in the mid-latitudes of the western Atlantic (in which case the remnants of Oscar could be contained within it)… or perhaps further east in the open central or eastern Atlantic if some of the western Atlantic upper vorticity shifts east as the latest model runs show. Therefore sometime during this upcoming week… could be adding an area of interest in future updates within the mid-latitudes of the Atlantic.
HURRICANE OSCAR… Special update #102A (https://www.infohurricanes.com/post/my-2024-atlantic-hurricane-season-birdseye-view-post-102a-special-update) covered the rapid genesis of Hurricane Oscar as it moved into the Turks and Caicos Islands. Weather conditions will improve overnight here and deteriorate for Inagua in the southeast Bahamas as the core of the hurricane is now moving west into the island. Also note heavy rainfall will also spread over Inagua and the remainder of the southeast Bahamas… and the remainder of the southeast Bahamas will also see some coastal surf. Due to the strength of the eastern US surface ridge the track is expected to deflect southwest into the north-facing coast of eastern Cuba through 24 hours. Currently Oscar’s small area of dense thunderstorms is oblong SW to NE… perhaps an indication of light northwesterly shear because the hurricane is on the northeast side of the western Caribbean upper anticyclone instead of closer to the anticyclone core. And due to the more north initial position of Oscar compared to prior forecasts… the hurricane is now more susceptible to increasing northerly shear in as soon as 24 hours due to the current eastern US upper vorticity which will soon expand the western Atlantic upper vorticity toward Oscar while merging with it. Thus I forecast Oscar to start weakening on approach to eastern Cuba. There is some disagreement in the models as to what happens with Oscar beyond 24 hours… some Oscar change to a northeast heading back into the southeast Bahamas into an expanding surface ridge weakness generated by the divergence zone of the aforementioned expanding west Atlantic upper vorticity… and others have Oscar become quasi-stationary near eastern Cuba in conflicting steering between the weakness and ongoing eastern US surface ridge. By 48 hours I elect that Oscar goes northeast back into the southeast Bahamas while attracted to surface pressure falls that will be occurring there in split flow upper divergence between the west Atlantic upper vorticity and west Caribbean upper anticyclone… which then leads me to continue Oscar northeast into the expanding surface ridge weakness after that time. I expect Oscar to increasingly weaken after 24 hours with the track taking it into increased shear imparted by the upper vorticity… and by 72 hours forecast Oscar to become an elongated remnant surface trough due to the forecast elongated divergence zone on the east side of the upper vorticity.
Regarding impact to land areas:
(1) See beginning of this Hurricane Oscar update for an update to impacts in the Turks and Caicos Islands and southeast Bahamas.
Also note a second round of gusty winds… heavy rain… and coastal surf is due for the southeast Bahamas by late Monday or early Tuesday given the current forecast.
(2) It appears Oscar has stopped intensifying due to early signs of shear… therefore my impact outlook for eastern Cuba is lowered a notch compared to special update #102A. I currently recommend that eastern Cuba should be preparing for hurricane conditions (coastal surf and with some damaging winds) on and just inland of the northeast coast arriving by tomorrow night. For areas on and just inland of the southeast Cuba coast… prepare now for less severe but still potentially damaging tropical storm force wind… some coastal surf is also possible. Heavy rainfall with flash flood potential will be another hazard across eastern Cuba… especially if Oscar ends up loitering near or over eastern Cuba for a prolonged period which could exacerbate rainfall totals.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0000Z Oct 20)… 85 mph maximum sustained wind hurricane centered between the Turks and Caicos Islands and Inagua at 21.3N-72.2W
IOH 24 Hr Forecast (0000Z Oct 21)… 70 mph maximum sustained wind tropical storm centered on the north-facing coast of east Cuba at 20.8N-75W
IOH 48 Hr Forecast (0000Z Oct 22)… 50 mph maximum sustained wind tropical storm centered between eastern Cuba and the southeast Bahamas at 21.5N-74W
IOH 72 Hr Forecast (0000Z Oct 23)… Remnant trough located northeast of the southeastern Bahamas near 23N-71.5W
*****National Hurricane Center (hurricanes.gov) official outlook as of 11 PM EDT*************************
Landfall (0000Z Oct 21)… 80 mph maximum sustained wind hurricane centered on the north-facing coast of east Cuba at 20.6N-74.8W
4-Day Position (0000Z Oct 24)… 40 mph maximum sustained wind tropical storm losing identity while centered in the west Atlantic at 27N-71.5W
TROPICAL DEPRESSION NADINE… Special update #102A (https://www.infohurricanes.com/post/my-2024-atlantic-hurricane-season-birdseye-view-post-102a-special-update) covered the formation of Nadine in the western edge of the Caribbean… followed by the landfall across northern Belize… northern Guatemala… and surrounding land areas. Nadine tonight has weakened further to a fading tropical depression due to the landfall… and should be downgraded to a remnant low centered near the NW corner of Guatemala by the NHC soon. This is my planned final statement on Nadine on this blog as I expect the eastern US surface ridge to be too strong to allow Nadine to track into the Bay of Campeche to re-develop there. Models are currently in agreement that the south side of the remnant low pressure field develops into an eastern Pacific tropical cyclone that tracks well offshore of southern Mexico while the northern part of the remnant low pressure field… which contains the current center of circulation of Nadine… dissipates over southeastern Mexico (see the NHC site… hurricanes.gov… for info on eastern Pacific activity which is not covered on this site). Expect periods of heavy rainfall with flash flood potential across Quintana Roo… Yucatan… Campeche… Tabasco… Chiapas… northern Guatemala… eastern Veracruz… and Oaxaca from the remnants of Nadine over the next day or so.
…COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Oct 19) CMC Model Run…
**For Hurricane Oscar… initialized at 0 hours as a tropical low which moves WSW into eastern Cuba thru 36 hours… turns on a north track into the central Bahamas through 96 hours… from there slowly drifts NE and dissipates in the western Atlantic waters NE of the central Bahamas by 162 hours
**For tropical depression Nadine… inland remnants lose their identity over SE Mexico through 48 hours
1200Z (Oct 19) ECMWF Model Run…
**For Hurricane Oscar… initialized at 0 hours as a tropical low which moves WSW into the eastern tip of Cuba thru 36 hours while becoming a compact tropical cyclone… the compact tropical cyclone then turns on a north track into the central Bahamas through 78 hours… while accelerating NNE toward Bermuda loses identity to new frontal low that develops directly over Bermuda by 114+ hours
**For tropical depression Nadine… inland remnants lose their identity over SE Mexico through 48 hours
1800Z (Oct 19) GFS Model Run…
**For Hurricane Oscar… initialized at 0 hours as a tropical low which moves WSW into the eastern tip of Cuba thru 24 hours while becoming a compact tropical cyclone… weakens back to a remnant low while drifting slowly west along southeast Cuba coast thru 48 hours… while becoming quasi-stationary further weakens to a broad surface trough over eastern Cuba and the southeastern Bahamas through 87 hours… through 102 hours loses identity to broad frontal low to the northeast developing in Bermuda’s proximity.
**For tropical depression Nadine… inland remnants lose their identity over SE Mexico through 48 hours
**Through 105 hours the tail end of surface front tied to current north Canada frontal cyclone settles into the northeast Atlantic between the Azores and Canary Islands… due to strong surface ridge behind the front the tail end of the front then evolves into surface low that dives southwest to 28N-32W thru 156 hours (surface low enhances by divergence at NE quadrant of upper vortex/vorticity that moves in from current west Atlantic position)… evolves into briskly strengthening tropical cyclone near 28N-32.5W through 168 hours
1800Z (Oct 19) NAVGEM Model Run…
**Not available at above-mentioned source
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