*******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 OCTOBER 8 2024 3:53 PM EDT...
The surface and upper air charts valid for October 7 are now included below. Brief remarks on areas of interest #39 to #41 are also now included.
For intense Hurricane Milton... the hurricane continued its eye wall replacement cycle which caused it to dip to a still ferocious category 4 intensity of 145 mph maximum sustained winds this morning. As discussed in the Milton section below... there was concern that Milton would re-intensify when the eye wall replacement cycle completed... and indeed on satellite pictures the new eye has become well-defined and contracted and aircraft recon has confirmed Milton's re-intensification to 155 mph maximum sustained winds this early afternoon. It is likely that Milton is re-upgraded to a category 5 hurricane by 5 PM EDT. Regarding position and track... Milton is now pulling northeast away from the south-central Gulf of Mexico northern Yucatan peninsula as it begins its expected turn toward the Florida peninsula.
...MONDAY OCTOBER 7 2024 11:59 PM EDT...
This post is initially released without discussion on areas of interest #39 to #41 due to the escalating situation with Milton in the Gulf of Mexico... to get this post published as soon as possible (areas of interest #39 and #40 are tropical waves of low pressure lined from the eastern tropical Atlantic to inland western Africa... and new area of interest #41 is the current eastern Gulf of Mexico surface low now crossing the southern Florida peninsula and northwestern Bahamas which may have a chance at tropical development while moving east-northeast toward Bermuda... none of these areas of interest are showing signs of immediate development and will add information for these areas of interest in this post within the hours ahead).
See remnants of Kirk... Hurricane Leslie... and Hurricane Milton sections below for more information on the current and formerly active tropical cyclones in the Atlantic basin. Intense Hurricane Milton is the most pressing situation as it is one of the strongest on record in the Atlantic basin... is now brining impacts to the northern Yucatan.. and will be impacting the Florida peninsula on Wednesday. In addition... noting that a frontal low is currently southeast of Newfoundland while supported by the divergence zone of the current amplified northwestern Atlantic upper trough. Although it has recently seen some increase in showers and thunderstorms on its north side... it is not enough to upgrade it to a tropical area of interest.
REMNANTS OF KIRK... While moving northeast into cooler northern Atlantic waters... Kirk completed its transition into a hurricane-force non-tropical frontal cyclone supported by the expansive eastern divergence zone of the current northwestern Atlantic upper trough as of 11 AM EDT (maximum sustained winds were 75 mph... or minimal hurricane force... during the final NHC advisory on Kirk). Going forward... ex-Kirk will be curving increasingly east in track while becoming entangled with the southwest quadrant of the current northeast Atlantic frontal cyclone... and the models remain in agreement on brining the center of ex-Kirk into France by Wednesday.
Regarding impact to land areas:
(1) Coastal surf is expected across the Azores for another 24 hours... and gusty winds cannot be ruled out.
(2) The combination of the current northeast Atlantic frontal cyclone and ex-Kirk following behind has extended the ongoing period of surf reaching the shores of the British Isles and mainland Western Europe... with gusty winds spreading onshore and across inland areas Tuesday and Wednesday from a one-two punch associated with the northeast Atlantic frontal cyclone landfall... then the landfall of ex-Kirk.
(3) This is my final statement on Kirk on this blog as it is no longer a tropical entity... future statements regarding impacts to land areas from ex-Kirk will be carried on the home page bulletins of this site.
HURRICANE LESLIE... Leslie and a wave of upper vorticity to its west are continuing generally west while pushed around the southwest quadrant of the eastern Atlantic surface ridge and also the southwest quadrant of a cell of tropical upper ridging which has recently moved into the eastern Atlantic from the central Atlantic. The west track of Leslie has an ongoing north component due to the southerly component of flow on the east side of the upper vorticity wave and southwest side of the eastern Atlantic surface ridge. The storm is north and west of the previous forecast and so my updated one is adjusted accordingly... with this initial position placing Leslie closer to southerly shear associated with the upper vorticity wave. As a result in the last 24 hours the thunderstorm activity has become more blobbed and lopsided toward the north side of the circulation... and the hurricane has slightly weakened from 90 to 85 mph maximum sustained winds. I currently forecast Leslie to regain a little strength in the next 24 hours as the shearing upper vorticity wave continues to fade from its prolonged isolation from high-latitude cold air... plus the hurricane may run into boosting split flow upper divergence between the west side of the east Atlantic tropical upper ridge cell and north side of the upper vorticity wave. After 24 hours the latest model runs continue to show the northwest/north Atlantic upper trough that is currently recurving Kirk northeastward also recurving the neighboring upper vorticity wave back east into Leslie... creating a surge of westerly wind shear. As such I forecast Leslie to lose hurricane strength by 48 hours. Between 48 and 72 hours the westerly wind shear greatly ramps up as the upper vorticity wave slides east overtop Leslie… with the shear direction then switching to northeasterly by 72 hours once the upper anticyclone currently in Milton's environment begins to approach Leslie. During this time I show a little more rapid weakening into a lower-end tropical storm. Noting the eastern convergence zone of the anticyclone may produce some blocking surface ridging to the west of Leslie… which is why the 72-hr northwest forward speed is reduced. By 96 hours the current east Canada upper trough contributes to a strong Atlantic Canada surface frontal cyclone. This frontal cyclone should proceed to weaken any blocking surface ridge west of Leslie and turn Leslie increasingly north then northeast through 120 hours. At around what is currently the 96 hour mark I now show a little re-strengthening instead of weakening as the north and west adjusted forecast track brings Leslie into the core of the upper anticyclone sooner where shear is lower and upper outflow is higher... with only slight re-strengthening an indication of how short-lived the exposure to favorable upper winds will be as the north to northeast accelerating track quickly brings the storm into more hostile westerly shear north of the anticyclone. By 120 hours a loss of tropical characteristics is expected as the Atlantic Canada frontal cyclone drives a surface cold front into the circulation of Leslie.
This forecast was completed at 1200Z earlier today... since then Leslie has continued to weaken under southerly shear and as of 11 PM EDT is a minimal hurricane with 75 mph maximum sustained winds.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (1200Z Oct 7)... 85 mph maximum sustained wind hurricane centered in the central tropical Atlantic at 16.4N-41.2W
IOH 24 Hr Forecast (1200Z Oct 8)... 90 mph maximum sustained wind hurricane centered in the central tropical Atlantic at 19N-46W
IOH 48 Hr Forecast (1200Z Oct 9)... 70 mph maximum sustained wind tropical storm centered in the central Atlantic at 22N-47.5W
IOH 72 Hr Forecast (1200Z Oct 10)... 45 mph maximum sustained wind tropical storm centered in the central Atlantic at 24N-49W
IOH 96 Hr Forecast (1200Z Oct 11)... 50 mph maximum sustained wind tropical storm centered in the central Atlantic at 28N-49W
IOH 120 Hr Forecast (1200Z Oct 12)... Remnant frontal low centered in the central Atlantic at 33N-46W
*****National Hurricane Center (hurricanes.gov) official forecast as of 11 AM EDT*************************
5-Day Position (1200Z Oct 12)... 40 mph maximum sustained wind remnant low centered in the central Atlantic at 27N-48.9W
MAJOR HURRICANE MILTON... Satellite image of Hurricane Milton around 0000Z tonight while peaking in intensity (180 mph maximum sustained winds with 897 mb minimum surface pressure):
The explosively intensifying and eastward-moving southern Gulf of Mexico hurricane... whose core is now passing just offshore of the northern Yucatan peninsula... is now one of the strongest recorded and fastest intensifying category 5 hurricanes in the Atlantic basin on record. The rapid intensification of Milton was documented in previous post #95 (https://www.infohurricanes.com/post/my-2024-atlantic-hurricane-season-birdseye-view-post-95). The southward deflection in the hurricane's east track has come to an end as the neighboring eastern Gulf of Mexico surface low responsible for this deflection (area of interest #41) is continuing east across the Florida peninsula and away from Milton... which means the hurricane's core will stay just offshore of the northern Yucatan in the next 24 hours. The eastward track is continuing in the flow ahead of upper vorticity that continues to approach from the south-central US. The tremendous latent heat release of Milton's strong thunderstorm core has pumped up the local warm core upper ridge/anticyclone to the degree the upper ridge is deflecting the westerly shear that would otherwise be imparted by the steering upper flow... and in this configuration the upper westerlies are also helping to enhance the northern outflow of the hurricane which is likely contributing to the amazing intensity of Milton. After 24 hours the approaching south-central US upper vorticity takes on a more north-south tilt while it continues to cyclonically arc around the current eastern Canada upper trough... shifting the upper flow over Milton from westerly to southwesterly which will cause a northeast turn toward the Florida peninsula. Noting the updated track forecast has a slower approach to the Florida peninsula as the modifications made by Milton's higher than expected thunderstorm latent heat release means a weaker version of the steering south-central US cool core upper vorticity... and I have also shifted the forecast track for a further north landfall on the west coast of the Florida peninsula (now predicting a just north of Tampa Bay landfall of the center) as the weaker version of the upper vorticity presented in the models has more southerly instead of southwesterly flow as Milton approaches Florida. Regarding short-term intensity... it appears the hurricane is peaking around 180 mph maximum sustained winds while the NHC since 5 PM EDT is citing the beginning of an eye wall replacement cycle. Accordingly I forecast weakening to a top-end category 4 through 24 hours until the eye wall replacement finishes... then re-intensification into a category 5 through 36 hours as the southwesterly upper flow curving Milton toward Florida appears it will enhance the northern outflow of the hurricane (much like how the current upper westerly flow is enhancing the hurricane's northern outflow). By 48 hours it appears the incoming upper vorticity will begin to suppress the hurricane's western outflow and so I begin to show weakening on approach to the Florida landfall.
For the latter part of the forecast period... the models are converging on the idea that just before passage over Florida the steering upper vorticity is coaxed back into a SW/NE tilt while dragged by eastern Canada upper trough's east shift into Atlantic Canada. This results in an increase in westerly wind shear and deflection of the track to a more east and less north angle... and I currently forecast Milton to begin quickly weakening under the increased shear to a minimal but still dangerous category 3 hurricane as it makes its east turn and landfall with Florida. And by day 4 a surface ridge builds north of Milton under the western convergence zone of the Atlantic Canada upper trough... slowing the east progress of Milton which further increases the shearing effect of the upper westerlies. The eastward forward speed is likely to increase by day 5 as Milton escapes the surface ridge... however the speed of the shearing upper westerlies will still be great enough to weaken the tropical cyclone to a remnant low by then.
Regarding impact to land areas:
(1) Interests across the northern Yucatan peninsula should have completed preparations by now as the southern side of Milton has overspread the area... with the powerful core of the hurricane being now just offshore.
(2) Interests across the Florida peninsula should continue preparing for potentially severe damage from strong hurricane force winds and coastal surge to arrive by Wednesday… the worst of which will be the on the west-facing coast but with significant impacts across inland areas and the east-facing coast as Milton would be moving quickly through the area and not have much time to weaken after the expected west coast landfall. This now includes the northern part of the peninsula as well as the latest forecast tracks as of this writing have trended towards the north. Listen to your local news media and local government officials for more information in the days ahead.
(3) Western Cuba… the Florida Keys… and the northwestern Bahamas will also see coastal surf… along with possible outer heavy rainfall bands bringing gusty winds. Western Cuba is expected to see these impacts by tomorrow... with the Florida Keys by late tomorrow and Wednesday… and the northwestern Bahamas by Thursday.
Note the above forecast was completed around 1800Z earlier this evening... since then (as of 11 PM EDT) an eye wall replacement cycle is indeed underway with the eye becoming cloud filled and larger on satellite pictures... and the NHC has estimated that maximum sustained winds have dipped to 165 mph with the minimum surface pressure rising to 914 mb.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (1800Z Oct 7)… 180 mph maximum sustained wind major hurricane centered just offshore of the northwestern Yucatan peninsula at 21.9N-90.8W
IOH 24 Hr Forecast (1800Z Oct 8)… 155 mph maximum sustained wind major hurricane centered just offshore of the northeastern Yucatan peninsula at 21.9N-86.5W
IOH 36 Hr Forecast (0600Z Oct 9)… 165 mph maximum sustained wind major hurricane centered offshore of northwestern Cuba at 23N-85.5W
IOH 48 Hr Forecast (1800Z Oct 9)… 140 mph maximum sustained wind major hurricane centered just southwest of Tampa Bay Florida at 26N-83.5W
IOH 60 Hr Forecast (0600Z Oct 10)… 115 mph maximum sustained wind major hurricane centered on the coast just north of Tampa Bay Florida at 28N-82.8W
IOH 72 Hr Forecast (1800Z Oct 10)… 95 mph maximum sustained wind hurricane centered offshore of northeastern Florida at 29.5N-79.5W
IOH 96 Hr Forecast (1800Z Oct 11)… 50 mph maximum sustained wind tropical storm centered in the western Atlantic at 30N-75W
IOH 120 Hr Forecast (1800Z Oct 12)… Remnant low centered southwest of Bermuda at 30N-68W
*****National Hurricane Center (hurricanes.gov) official forecast as of 5 PM EDT*************************
Peak strength (0600Z Oct 8)… 185 mph maximum sustained wind major hurricane centered just offshore of the northern Yucatan peninsula at 21.9N-89.4W
Landfall (0600Z Oct 10)… 125 mph maximum sustained wind major hurricane centered over Tampa Bay Florida at 27.9N-82.6W
5-Day Position (1800Z Oct 12)… 45 mph maximum sustained wind frontal cyclone centered just south of Bermuda at 31N-65W
AREA OF INTEREST #39... Update as of 3:15 PM EDT Tuesday October 8... the tropical wave of low pressure that entered the eastern tropical Atlantic from Africa on Sunday is producing limited shower and thunderstorm activity on its south side while the north side is suppressed by dry Saharan air. Due to the ongoing gradual reduction in its activity I am cancelling this tropical wave as an area of interest in future updates.
AREA OF INTEREST #40... Update as of 3:15 PM EDT Tuesday October 8... the tropical wave of low pressure over interior western Africa has become better-defined over the last couple of days with a distinct area of thunderstorms that shows cyclonic banding at times. Within the next few days the current residual upper vorticity in the eastern Atlantic will be merging with the current northwest/north Atlantic upper trough... with the merger resulting in an eastern Atlantic upper trough which dives south due to the force of a mid-ocean upper anticyclone that will be over Leslie (see Leslie section above for more info on the upper anticyclone). After the tropical wave enters the eastern tropical Atlantic within the next couple of days... this upper trough is likely to bend the track of this tropical wave northwest into the Republic of Cabo Verde Islands by Friday... and as of this writing the NHC assigns a 20% chance of tropical cyclone formation. I am currently bumping up the wave's odds of development to 30% as it has become better defined as noted above.
AREA OF INTEREST #41... Update as of 3:15 PM EDT Tuesday October 8... the surface low pressure that was in the eastern Gulf of Mexico has zoomed east across south Florida and the northwestern Bahamas while in a tunnel of deep-layer westerly flow ahead of an approaching surface cold front driven by the current eastern Canada frontal low... and upper westerlies on the south sides of the current eastern Canada and northwest/north Atlantic upper troughs. This system may struggle to undergo tropical development due to shear imparted by the upper westerlies... however recent satellite imagery shows an increase in concentrated thunderstorm activity to the east of the northwestern Bahamas. In addition the CIMSS 850 mb vorticity (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=) shows the low-level spin becoming concentrated toward the thunderstorms. This location of increasing spin and thunderstorms is south enough that this system is likely to pass just south of Bermuda over the next day or so while continuing to be guided east-northeast in the tunnel of deep-layer westerlies... however note coastal surf would still occur at Bermuda. The more south position also places this system away from the worst of the shearing upper westerlies... and so I am assigning a 40% chance of tropical cyclone formation which is higher than the NHC's current 20% as of this writing.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
0000Z (Oct 7) CMC Model Run...
**For Hurricane Leslie... weakens back to a tropical storm while moving west-northwest to 19N-46W through 42 hours... weakens to a remnant low near 25N-51W at 114 hours... after merging with cold front the remnant low continues northeast to 30.2N-40.5W through 168 hours
**For Major Hurricane Milton... passes just offshore of the northern Yucatan peninsula through 48 hours... begins to weaken just before landfall with southwestern Florida with landfall time at 108 hours... as a sheared tropical storm passes north of the northwestern Bahamas by 132 hours then proceeds to become an elongated remnant frontal low near 30N-74.5W by 144 hours... remnant frontal low loses identity just south of Bermuda by 162 hours while adjacent frontal low to the ENE becomes the dominant.
**For area of interest #39... no development shown
**For area of interest #40... tropical wave emerges from west coast of Africa at 66 hours and develops into a tropical low that moves into the Republic of Cabo Verde Islands through 102 hours... tropical low proceeds west-northwest to 20N-33.5W by 168 hours
**For area of interest #41 (eastern Gulf of Mexico frontal low)... no tropical development shown as frontal low accelerates east-northeast into the waters just southeast of Bermuda through 84 hours and losing identity along the cold front shortly thereafter
0000Z (Oct 7) ECMWF Model Run...
**For Hurricane Leslie... weakens to a tropical storm while reaching 22.5N-50W by 90 hours... weakens to a remnant low near 26N-50.5W by 126 hours... remnant low dissipates near 30N-48.85W by 150 hours
**For Major Hurricane Milton... passes just offshore of the northern Yucatan peninsula through 30 hours... proceeds to turn northeast with landfall over west-central Florida at 72 hours... proceeds to turn on a wobbling east track and as a sheared tropical storm passes just north of the northwestern Bahamas by 90 hours... weakens to a remnant low south-southwest of Bermuda (near 28.8N-66.5W) at 144 hours... remnant low reaches 29N-61W by 168 hours
**For area of interest #39... no development shown
**For area of interest #40... tropical wave emerges from west coast of Africa at 60 hours and briefly develops into a tropical low just east of the Republic of Cabo Verde Islands through 96 hours... no development shown thereafter as tropical low opens back to a wave
**For area of interest #41 (eastern Gulf of Mexico frontal low)... lowest surface pressure re-locates east over the northwestern Bahamas through 36 hours and passes directly over Bermuda through 78 hours while becoming increasingly circular but not quiet presenting a tight tropical core of low surface pressures... while becoming wrapped into Atlantic Canada frontal cyclone and supportive eastern divergence zone of its associated upper vorticity the frontal low proceeds to curve north and strengthen into a frontal cyclone offshore of the southern tip of Greenland through 126 hours... the frontal cyclone proceeds to whirl west then southwest into Newfoundland through 168 hours while undergoing typical post-mature decay phase underneath part of overhead upper vorticity that lacks upper divergence.
1200Z (Oct 7) GFS Model Run...
**For Hurricane Leslie... weakens to a tropical storm while moving northwest to 24.5N-48.5W through 87 hours... while proceeding northeast ahead of surface cold front weakens to a remnant low near 29.8N-45.5W through 117 hours... while merging with cold front the remnant low proceeds east-northeast into the Azores through 168 hours
**For Major Hurricane Milton... passes just offshore of the northern Yucatan peninsula through 24 hours... proceeds to turn northeast with landfall over the northwestern Florida peninsula (just north of Tampa Bay Florida) at 66 hours... turns increasingly east while gradually weakening to a tropical storm due to landfall and increasing wind shear and passes north of the northwestern Bahamas at 87 hours... transitions into a remnant frontal low near 30N-70W by 114 hours... remnant frontal low passes just southeast of Bermuda by 132 hours and while east of Bermuda loses identity along the cold front by 144 hours.
**For area of interest #39... no development shown
**For area of interest #40... tropical wave emerges from west coast of Africa at 60 hours and develops into a tropical low that moves into the Republic of Cabo Verde Islands by 93 hours... weakens to a surface trough while reaching 20N-35W through 168 hours
**For area of interest #41 (eastern Gulf of Mexico frontal low)... lowest surface pressure re-locates east over the northwestern Bahamas through 27 hours... while proceeding quickly east-northeast the frontal low potentially transitions into a tropical cyclone while located near 28.5N-71.5W at 39 hours with the possible tropical cyclone passing just south-southeast of Bermuda at 69 hours... the tropical cyclone transitions back into a frontal low while located near 31.2N-60W at 81 hours shortly after which time the remnant frontal low loses identity along the cold front
1200Z (Oct 7) NAVGEM Model Run...
**Not available at above-mentioned source
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