BIRDSEYE VIEW POSTS

Since 2012 on the Weather Underground (www.wunderground.com) 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 via Disqus on Weather Underground at www.wunderground.com/cat6. You can see my Disqus feed at this link for my latest comments. Feel free to reply to me with your disqus account or e-mail at IOHurricanes@outlook.com 

 
 
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MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #20

*******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.**********


...TUESDAY JUNE 2 2020 2:11 PM EDT...

Area of interest in the Bay of Campeche has become Tropical Depression Three and now very recently Tropical Storm Cristobal...see Depression Three/Cristobal section below for details. See area of interest section below for frontal cyclone east of the Azores I am currently monitoring for acquisition of tropical characteristics.


TROPICAL DEPRESSION THREE (UPGRADED TO TROPICAL STORM CRISTOBAL)...The 2020 Atlantic Hurricane Season is off to a hyper start. Today is only the second official day of the season. But in the last 24 hours the surface tropical low pressure that entered the eastern Bay of Campeche from southeatern Mexico was upgraded to Tropical Depression Three...and very recently Tropical Storm Cristobal...the earliest third named storm in the Atlantic basin on record! Cristobal and an ongoing broader surface low pressure over Central America to the southeast are supported by a sprawling upper ridge/outflow over the region. The central pressure of 1004 mb is a bit lower than typical for 40 mph maximum sustained winds...normally would expect winds to be a bit higher for that pressure. This indicates to me that Cristobal and the broad surface low pressure area seem to be melting together...with the broad low pressure keeping the pressure gradient between the center and outside of Cristobal relaxed such that winds are on the lower side. This appears to also be evident by the fact that Cristobal has not moved as far west as I previously anticipated...instead already drifting back southwest back toward the Mexico Bay of Campeche coast as if it is already melting with the broad surface low pressure area rather than orbiting it. This has caused me to shift the short-term forecast track eastward. In the latter part of the forecast period...Cristobal is expected to interact with the upper vorticity currently over Texas/northern Mexico...with the vorticity shifting eastward closer to Cristobal as the western North America upper ridge eventually shifts eastward. The upper vorticity should draw Cristobal northward along the western Yucatan peninsula shore...then across the Gulf of Mexico and toward the United States Gulf coast. Regarding intensity...even though there is aformentioned evidence of a relaxed surface pressure gradient...I forecast Cristobal to still reach 60 mph maximum sustained winds as it drifts southward and makes landfall on the Bay of Campeche Mexico coast in the next 24 hours...due to a banding-type eye feature seen in recent visible and infrared satellite. I then drop the strength to tropical depression status at 48 and 72 hours due to forecast land interaction with the western Yucatan shore...followed by another round of strengthening as Cristobal hurtles northward across the open Gulf of Mexico. Intensity is split in the models...with the CMC and GFS showing a large/broad tropical storm that struggles to tighten up due to the large area of divergence on the east side of the upper vorticity that would keep surface pressure around Cristobal low...and ECMWF (Euro) and NAVGEM which show Cristobal developing a tight core and strengthening into a strong tropical cyclone...perhaps a hurricane. The 0600Z GFS model at 96 hours seemed to hint at how Cristobal could strengthen more rapidly in the open Gulf of Mexico...while showing the upper vorticity being a bit overidden by anticyclonic outflow induced by Cristobal's latent heat release...which would keep wind shear unfavorable to Cristobal on the lower side (but by 120 hours the GFS shows the upper vortex dominate...keeping Cristobal on the weaker side). I think because of Cristobal's initial more east position further away from the upper vortex...which will give it more room to fight against the vortex...there is some possiblity of this occurring. But this will only occurr if Cristobal stays over water or over the coast over the next 72 hours...as a track further inland would weaken Cristobal and make it succumb to the broader surface low pressure around the storm...thus making it harder to redevelop a tight center when it later moves over the Gulf of Mexico. Since we don't know if Cristobal will stay over water in the short-term...I am not comfortable forecasting hurricane strength at this time at 120 hours...instead picking a strength just below hurricane force. This intensity is more in line with climatology and also with the northern Gulf of Mexico havig water temps just above the 26 deg C threshold for tropical development...and such strength is not uncommon in June Atlantic tropical storms in the Gulf of Mexico...hurricane strength this time of year on the other hand is more rare. But such tropical storms can still bring damaging wind and storm surge to coastal areas...so its becoming increasingly clear that the United States Gulf coast will have to watch Cristobal for impacts just after 5 days. But we also have to be concerned about the flooding risk to southeastern Mexico and parts of Central America as Cristobal and the adjacent borad surface low pressure area will continue to linger in the area over the next 3 days...see bulletins at the home page of this site for details.

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

0 Hr Position (1200Z Jun 2)...40 mph maximum sustained wind tropical storm centered in the Bay of Capeche at 19.3N-92.7W

IOH 24 Hr Forecast (1200Z Jun 3)...60 mph maximum sustained wind tropical storm making landfall on Mexico Bay of Campeche coast at 18.5N-92W

IOH 48 Hr Forecast (1200Z Jun 4)...35 mph maximum susatained wind tropical depression centered along western Yucatan peninsula coast at 19.5N-90W

IOH 72 Hr Forecast (1200Z Jun 5)...35 mph maximum susateined wind tropical depression centered along the northwestern Yucatan peninsula coast at 21N-90W

IOH 96 Hr Forecast (1200Z Jun 6)...50 mph maximum sustained wind tropical storm centered in the Gulf of Mexico at 24N-89W

IOH 120 Hr Forecast (1200Z Jun 7)...70 mph maximum sustained wind tropical storm centered just offshore of southeastern Louisiana at 29N-88.5W


AREA OF INTEREST #1...Deep-layer ridging in the far north Atlantic has amplified further due to warm air advection ahead of a quickly developing northwest Atlantic frontal cyclone...which has resulted in the elongated upper vortex east of the Azores consolidating into a circular more consolidated vortex...in turn causing its surface frontal low pressure supported by the eastern divergence of the vortex to also become more circular and more consolidated while strengthening further into a frontal cyclone. Colorized infrared satellite suggests shower and thunderstorm activity near the center of the frontal cyclone is of limited intensity...maybe suggesting the cold upper vortex is not quiet cold enough to kick up thunderstorms over the 18 to 20 deg C waters. Thus I have lowered my odds of the frontal cyclone transitioning into a subtropical cyclone to 20%. The upper vortex will begin drifting southeastward thru the forecast period as an upper trough fragment currently just north of the British Isles will swing south around the north Atlantic ridge while trying to capture the upper vortex. In the next 24 hours teh frontal cyclone is forecast to swing southwest closer to the easternmost Azores while caught in the north side of the eastward-drifitng upper vortex. For the longer range...current observations and modeling continue to suggest a stronger north Atlantic ridge which keeps the upper vortex and trough fragment more seperate...thus slowing the east track of the vortex. My updated long range track forecast is in alignment with the CMC...GFS...ECMWF consensus which shows a slower east track. I begin dropping odds of development at 72+ hours as the surface frontal cyclone will eventually weaken while settling beneath the core of the upper vortex...an environment that lacks supportive upper divergence.

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

IOH 24 Hr Outlook (1200Z Jun 3)...20% chance of subtropical cyclone formation (just southeast of the Azores near 35N-23.5W)

IOH 48 Hr Outlook (1800Z Jun 4)...20% chance of subtropical cyclone formation (between the Azores and Canary Islands near 34N-22.5W)

IOH 72 Hr Outlook (1800Z Jun 5)...10% chance of subtropical cyclone formation (west of the Canary Islands near 33N-21.5W)

IOH 96 Hr Outlook (1800Z Jun 6)...0% chance of subtropical cyclone formation (just west of the northern Canary Islands at 33N-19W)


...COMPUTER MODEL SUMMARY...

Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)


0000Z CMC Model Run...For tropical depression three...through 90 hours cyclonically loops the track of this system in Bay of Campeche/western Yucatan coast region...has system accelerating northward in Central Gulf of Mexico by 120 hours. For area of interest #1...shows frontal cyclone looping east of the Azores through 48 hours...shifting south to a position west of the Canary Islands by 72 hours...then shifting east into the Canary Islands and losing its identity by 114 hours.


0000Z ECMWF Model Run...For tropical depression three...through 96 hours cyclonically loops the track of this system in Bay of Campeche/western Yucatan coastal region...potentially strengthening into a strong tropical cyclone just offshore. By 120 hours has system accelerating northward into the central Gulf of Mexico as a potentially strong tropical cyclone. For area of interest #1...shows frontal cyclone looping east of the Azores through 48 hours...shifting south to a position west of the Canary Islands by 72 hours...then shifting east into the Canary Islands and losing its identity by 120 hours.

0600Z GFS Model Run...For tropical depression three...through 36 hours cyclonically loops the track of this system in the eastern Bay of Campeche till landfall on the southwest coast of Campeche province...potentially strengthening into a strong tropical cyclone just offshore and before the landfall. Remnants lose identity within broad surface low to the southeast and then shift northward across western Yucatan through 90 hours. Broad surface low pressure consolidates into possible tropical cyclone while continuing north across central Gulf of Mexico by 120 hours. For area of interest #1...shows frontal cyclone looping east of the Azores through 48 hours...shifting south to a position west of the Canary Islands by 72 hours...then shifting east into the Canary Islands and losing its identity by 108 hours.


0600Z NAVGEM Model Run...For tropical depression three...through 90 hours cyclonically loops the track of this system in Bay of Campeche/western Yucatan coastal region...potentially strengthening into a strong tropical cyclone just offshore. By 120 hours has this system quickly accelerating north into southeastern Lousiana as a potentially strong tropical cyclone. For area of interest #1...shows frontal cyclone looping east of the Azores through 30hours...shifting east-southeast into the northern Canary Islands by 78 hours...then losing its identity between the Canary Islands and Portugal by 102 hours.

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