*******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.*********
...THURSDAY JUNE 20 2024 9:00 AM EDT...
The Atlantic tropics remain busy for mid-June as the center of Tropical Storm Alberto makes landfall near the Veracruz/Tamaulipas border region... with two other concurrent areas of interest following behind as follows:
See Alberto section below for an update on the tropical storm which has recently made landfall over east-central Mexico. See area of interest #7 section below for information on a gyre of low pressure that could materialize over the Caribbean and Central America... and head toward the Gulf of Mexico in the immediate wake of area of Alberto.
See area of interest #6 section below for an update on the current western Atlantic surface trough of low pressure which has become better organized over the last 36 hours. There is a higher chance this system could become a tropical depression or weak tropical storm while passing just north of the northwestern Bahamas... followed by a landfall over the northern Florida peninsula... within the next 36 hours.
Elsewhere... yet another vigorous tropical wave of low pressure featuring rotating thunderstorm activity is emerging from the west coast of Africa and into the far eastern tropical Atlantic. Although upper winds are generally favorable for development in this region as a tropical upper ridge with low shear and outflow persists here... none of the models develop this wave likely as it ingests dry Saharan air currently located to the northwest.
TROPICAL STORM ALBERTO... See the update at the top of previous post #21 for discussion of Alberto's formation yesterday in the western Gulf of Mexico (https://www.infohurricanes.com/post/my-2024-atlantic-hurricane-season-birdseye-view-post-21). Overnight the center of the tropical storm has proceeded westward and as of this writing is now making landfall at the Veracruz/Tamaulipas border region of Mexico. While on approach to landfall... the minimum surface pressure fell further to 993 mb which allowed the tropical storm to strengthen further to 50 mph maximum sustained winds. The outer circulation of the tropical storm is still large... but is beginning to take on a more conventional consolidated structure as the wind field has shrunken in size and is no longer covering southern Texas. The surface ridge currently building over the north-central United States will push Alberto into interior central Mexico over the next 24 hours. Coastal surf affecting southern Texas... Tamaulipas... and northern Veracruz will subside during this time as the tropical storm weakens to a remnant low due to the landfall... along with the gusty winds across Tamaulipas and Veracruz. Doppler radar shows heavy rainfall as far northwest as south-central Texas... and colorized infrared satellite shows thunderstorms and heavy rainfall spreading into central Mexico from east-central Mexico. Flash flooding is a possible hazard... spreading as far west as west-central Mexico as Alberto continues inland... over the next 24 hours.
This is my planned final statement on Alberto on this blog as it is expected to transition into an inland dissipating remnant low in the next 24 hours.
Update as of 8 AM EDT... Alberto has weakened to 45 mph maximum sustained winds while now centered just inland over the Tamaulipas/Veracruz border region.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0600Z Jun 20)... 50 mph maximum sustained wind tropical storm centered just offshore of the Tamaulipas/Veracruz border at 22.3N-97.3W
IOH 24 Hr Forecast (0600Z Jun 21)... Dissipating remnant low over interior central Mexico centered at 23N-101.5W
******National Hurricane Center (hurricanes.gov) official forecast as of 5 AM EDT***************************
Dissipation (1800Z Jun 20)... 35 mph maximum sustained wind dissipating tropical depression centered over interior central Mexico at 22.1N-100.6W
AREA OF INTEREST #6... The western Atlantic surface trough of low pressure has spent the last 36 hours accelerating west-northwest in the general direction of the northwesternmost Bahamas islands and east coast of the Florida peninsula as the current northwest Atlantic and north-central US surface ridges begin to merge into a NW/SE tilted steering feature. As it did so it became better organized into a compact tropical low with curved thunderstorm bands on its north side... which more than what recent model runs were predicting. This system is embedded in a dynamic upper wind environment to the southeast of the ongoing heat wave upper ridge over eastern North America... where the upper ridge has been breaking off pieces of the current north Atlantic upper trough into southwestward-retrograding upper vortices... as such there is one large upper vortex to the southwest of this area of interest and a second smaller upper vortex materializing to the northeast. Previous model runs suggested this system would be suppressed by the northeast half of the southwestern vortex where upper divergence is lacking... instead the southwestern vortex is not quiet as large as previous forecasts which has allowed this area of interest to be tucked in a small area of supporting outflow between the two vortices... which would help explain how this system has developed more than previous recent model runs suggested.
The current position of the small tropical low of interest is west of previous forecasts while the forward speed is faster than previous projections... and my updated forecast track in the outlook below is adjusted accordingly. As such this system has 36 hours to develop before making landfall with the east coast of Florida... after which time the ongoing west-northwest track should keep this system inland which would prevent further tropical development (also the next frontal system to approach from western North America should keep the remnants of this system curving northwestward further inland into the southeastern US). Because this system is now projected to stay in the small region of supporting outflow between the two upper vortices... I have increased my odds of tropical cyclone formation to 50% for the pre-landfall period of time.
This system has a higher likelihood of passing just north of the northwestern Bahamas as a tropical depression in the next 24 hours... the Great Abaco and Grand Bahama islands may see bands of heavy rainfall from this system during this time. By Friday evening this system could be making landfall on the east coast of Florida as a tropical depression or weak tropical storm... periods of heavy rainfall with flash flooding cannot be ruled out for the central and northern parts of the Florida peninsula along with the possibility of some wind gusts... coastal surf would also be possible for the east-central and northeastern Florida coast.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0600Z Jun 21)... 50% chance of tropical cyclone formation (just north of the northwestern Bahamas at 27.5N-78W)
IOH 48 Hr Outlook (0600Z Jun 22)... 0% chance of tropical cyclone formation (interior north-central Florida peninsula near 28.5N-82W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 8 AM EDT***************************
Formation chance through 48 hours... 40%
Formation chance through 7 days... 40%
AREA OF INTEREST #7... Based on the shape of the isobars (lines of constant pressure) in the 0600Z NHC TAFB surface analysis... it appears a surface trough of low pressure extends from Alberto southeastward across the Bay of Campeche... southern Yucatan peninsula... western Caribbean... and into the north coast of Honduras. This band of low surface pressures is being supported by the southeastern outflow of the upper ridge over Alberto plus split flow upper divergence between the southwestern quadrant of the upper vortex currently centered over western Cuba and southeastern quadrant of the aforementioned upper ridge. Over the next 24 hours I continue to forecast that the eastern (Caribbean) part of this surface trough has a high potential to become a tropical low as the upper vortex accelerates westward and away while weakening from its prolonged isolation from high-latitude cold air... allowing the eastern part of the surface trough to become enhanced by the southeastern divergence zone of the departing upper vortex. However I show 0% odds of tropical cyclone formation as the east side of the upper vortex will still be near enough to induce disprutive southerly shear. By 48 hours the weakening upper vortex continues westward which allows for an expanding area of anticyclonic outflow and lowering wind shear... and this is when I raise odds of tropical cyclone formation above 0%. However I keep odds of development at a low 10% as the upper winds become favorable only right before this system makes landfall with Belize or the Yucatan peninsula of Mexico. The forecast tropical low pressure circulation continues west-northwest across the Yucatan and into the western Gulf of Mexico in the longer range while at first pushed by the same surface ridge steering area of interest (AOI) #6. The northward angle in the forecast track increases through day 5 due to a pair of surface frontal systems to eject from western North America... however with a slow forward speed as the frontal systems pass well to the north. Through day 4 there is some uncertainty in how favorable the upper winds will be for development as the lobe of upper vorticity currently northeast of AOI #6 works its way into the northern Gulf of Mexico as an east-west band where it may suppress the northern outflow of this area of interest. However by day 5 there is agreement in the models that the upper vorticity dissipates from prolonged isolation from high-latitude cold air... therefore I gradually increase odds of development in the 3 to 5 day window.
Regardless of tropical cyclone formation or not... the main takeaway for this area of interest is that it could produce heavy rainfall with flash flooding potential across western Central America and southeastern Mexico in the days ahead. The flooding risk here is enhanced as what was the pre-Alberto circulation recently saturated the grounds in this region.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0600Z Jun 21)... 0% chance of tropical cyclone formation (western Caribbean and offshore of northeastern Honduras near 16.5N-85.5W)
IOH 48 Hr Outlook (0600Z Jun 22)... 10% chance of tropical cyclone formation (Caribbean coast just north of the Belize/Mexico border near 18N-88W)
IOH 72 Hr Outlook (0600Z Jun 23)... 10% chance of tropical cyclone formation (southwestern corner of Yucatan peninsula near 19.2N-90.2W)
IOH 96 Hr Outlook (0600Z Jun 24)... 20% chance of tropical cyclone formation (southwestern Gulf of Mexico near 22N-92W)
IOH 120 Hr Outlook (0600Z Jun 25)... 30% chance of tropical cyclone formation (western Gulf of Mexico near 24N-94W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 8 AM EDT***************************
Formation chance through 48 hours... 20%
Formation chance through 7 days... 50%
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
0000Z (Jun 20) CMC Model Run...
**For Tropical Storm Alberto... makes landfall near Tamaulipas/Veracruz border region in next 12 hours... rapidly dissipates inland over interior central Mexico (near 22N-101W) at 18+ hours
**For area of interest #6... through 48 hours approaches the Florida/Georgia border coastal region while weakening to a surface trough which then dissipates after landfall
**For area of interest #7... Broad low pressure field persists across Bay of Campeche... western Caribbean... and adjacent regions in wake of area of Alberto (12 to 24 hours)... consolidates into an eastern Bay of Campeche tropical low by 48 hours with possible tropical cyclone formation suggested as this system makes landfall near southern Tamaulipas by 114 hours... rapidly dissipates inland shortly thereafter
0000Z (Jun 20) ECMWF Model Run...
**For Tropical Storm Alberto... makes landfall near Tamaulipas/Veracruz border region in next 12 hours... rapidly dissipates inland shortly thereafter
**For area of interest #6... through 42 hours approaches the northeast Florida coastline while weakening to a surface trough which then dissipates after landfall
**For area of interest #7... Broad low pressure field persists across Bay of Campeche... western Caribbean... and adjacent regions in wake of area of Alberto (12 to 24 hours)... Bay of Campeche portion of circulation becomes dominant through 54 hours and then proceeds to make landfall as an elongated surface trough along the Veracruz and Tamaulipas coastline through 114 hours without tropical cyclone formation prior to the landfall
0000Z (Jun 20) GFS Model Run...
**For Tropical Storm Alberto... makes landfall near Tamaulipas/Veracruz border region in next 12 hours... inland remnant low proceeds to accelerate west across interior central Mexico and dissipates over west-central Mexico near 22N-103W
**For area of interest #6... through 36 hours approaches the northeast Florida coastline while weakening to a surface trough which then dissipates after landfall
**For area of interest #7... Broad low pressure field persists across Bay of Campeche... western Caribbean... and adjacent regions in wake of area of Alberto (12 to 24 hours)... eastern Bay of Campeche circulation becomes the dominant through 54 hours and proceeds to make landfall on the central Tamaulipas coast through 114 hours without tropical cyclone foramtion prior to the landfall
0000Z (Jun 20) NAVGEM Model Run...
**For Tropical Storm Alberto... makes landfall near Tamaulipas/Veracruz border region in next 12 hours and dissipates inland shortly thereafter
**For area of interest #6... makes landfall on the east Florida coast as an elongated and weak surface trough at 30 hours... trough proceeds west-northwest across the Florida panhandle and southern Alabama and subsequently dissipates over central Mississippi at 60+ hours
**For area of interest #7... Broad low pressure field persists across Bay of Campeche... western Caribbean... and adjacent regions in wake of area of Alberto (12 to 24 hours)... eastern Bay of Campeche portion of the circulation becomes the dominant by 48 hours with tropical cyclone formation suggested near 21N-94W by 60 hours... tropical cyclone weakens to remnant low while moving northwest into Tamaulipas/Veracruz border through 108 hours and rapidly dissipates inland shortly thereafter
**Broad low pressure field persists across Bay of Campeche... western Caribbean... and adjacent regions in wake of area of interest #7 (108 to 144 hours with brief spin-up offshore of Veracruz at around 126 hours)... the western Caribbean portion of the circulation becomes the dominant through 150 hours and proceeds to make landfall on the Belize/Mexico border at 162 hours
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