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 #21

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


...WEDNESDAY JUNE 3 2020 1:50 PM EDT...

Tropical Storm Cristobal makes landfall in southeastern Mexico...see Cristobal section below for additional details and updated outlook on the storm. See area of interest section below for final statement on frontal low pressure system east of the Azores no longer expected to acquire tropical characteristics.


TROPICAL STORM CRISTOBAL...My previous forecast track and intensity have been spot-on over the last 24 hours...with Cristobal drifting southward across the southwestern Campeche province coast for a landfall...with maximum sustained winds reaching 60 mph just before this morning's landfall when Cristobal fired a tower of thunderstorms over the center. It is likely that Cristobal at this very moment is below its 60 mph intensity as the infrared satellite presentation shows degradation beginning after the landfall. Despite the performance of my previous forecast...I am making some adjustments as satellite loops show Cristobal's center continuing to drift south further inland over the Campeche/Tabasco border rather than staying along the coast. My solution is now similar to the latest short-term GFS and NAVGEM models which show Cristobal continuing to get pulled well inland into the remainder of the broad surface low pressure area to the southeast. It is conceivable that Cristobal's currently tighter center completely loosens and loses its identity within the broader low pressure area...with the broader low pressure area later lifting northward into the Gulf of Mexico and becoming a second seperate tropical cyclone. For now in the forecast below...assuming that this will be one long continuous tropical cyclone event retaining the name of Cristobal...with the assumption that Cristobal's current circulation later regenerates over the Gulf of Mexico. The eventual shift northward into the Gulf of Mexico will occurr as the broad low pressure system transitions into a feature supported by the eastern divergence zone of the upper vortex currently advancing into the western Gulf from Texas. A northward track will also be supported as the surface ridge over the southeastern United States will be eroded by the same upper divergence zone. I have lowered the intensity forecast a notch because the current track well inland should cause Cristobal to lose its current tight circulation...and the circulation will likely remain broad through the forecast period as the region of upper divergence on the east side of the upper vortex will be large...keeping the low surface pressures spread over a larger/broader area. Also the upper vortex will likely disrput the western half of Cristobal's circulation and block the wester upper outflow of the system. I am keeping my forecast track on the east edge of the latest NHC advisory track guidance...due to the latest CMC-NAVGEM-ECMWF-GFS model consensus and as the upper vortex appears large enough in the latest GFS model upper wind field to keep the tropical storm further east. However after landfall over southeastern Louisiana (just after 96 hours)...I support the idea of a northwestward swing in track as the current upper trough energy over southwestern Canada will be over the northeastern United States...positioning the western convergence zone of the upper trough and resulting surface ridge to the northeast of the tropical storm...close enough for the ridge to potentially add a west component to the storm track. Also in the upper layers the steering supports a west component as the longwave upper ridge over western North America shifts east to a position directly north of Cristobal. The eastward shift of the longwave ridge will be from another upper trough and surface frontal system over the western United States whose vigorous warm air advection should also weaken the upper vortex around the 96+ hour landfall time...the absence of the vortex making it easier for Cristobal to also lean west. Interests on the United States Gulf coast from Louisiana to the Florida panhandle should continue to monitor the progress of Cristobal for possible storm surge and wind impact...thinking about what preparations would be needed but not necessarily acting upon them till the forecast becomes more clear. In the immediate-term we also have to still be concerned about the flooding risk to southeastern Mexico and parts of Central America as Cristobal and the adjacent broad surface low pressure area will continue to linger in the area over the next 2 days...see bulletins at the home page of this site for details. Even though the strengthening of Cristobal over the last 24 hours tightened most of the weather in the region to a smaller area such that weather conditions cleared up over Central America...still expecting a flood risk due to already-saturated ground from the previous rainfall and potential for another round of rainfall as Cristobal weakens/loosens up which could allow the weather to return over Central America.

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

0 Hr Position (1200Z Jun 3)...60 mph maximum sustained wind tropical storm making landfall on Mexico Bay of Campeche coast at 18.6N-92W

IOH 24 Hr Forecast (1200Z Jun 4)...Remnant low pressure centered over the northwestern Mexico/Guatemala border at 17.5N-91W

IOH 48 Hr Forecast (1200Z Jun 5)...Remnant low pressure centered over the southwestern Yucatan peninsula at 19N-89.5W

IOH 72 Hr Forecast (1200Z Jun 6)...35 mph maximum sustained wind tropical depression centered in the Gulf of Mexico at 24N-88.5W

IOH 96 Hr Forecast (1200Z Jun 7)...60 mph maximum sustained wind tropical storm centered just offshore of southeastern Louisiana at 29N-88W

IOH 120 Hr Forecast (1200Z Jun 8)...35 mph maximum sustained wind tropical depression centered over southwestern Mississippi at 31.5N-91W


AREA OF INTEREST #1...Deep-layer ridging in the far north Atlantic remains amplified due to warm air advection ahead of a frontal cyclone that has swung north into southeastern Canada from the northwest Atlantic...which has resulted in a continued cut-off upper vortex and associated surface frontal cyclone located just east of the Azores. Despite being rather cold...the upper vortex does not appear to be cold enough to kick up thunderstorm activity with the fact that the surface cyclone is over 18 to 20 deg C waters...therefore I am dropping the odds that the surface cyclone becomes subtropical to 0%. Going forward...current observations and modeling continue to suggest a stronger north Atlantic ridge which keeps the upper vortex and trough fragment diving south from northern Europe more seperate...thus slowing the eastward progress of the upper vortex toward this trough. Thus a slow track eastward toward the northern Canary Islands is expected as the surface cyclone weakens due to the lack of divergence directly below the upper vortex center...therefore gusty winds over the northern Canary Islands are not expected. This is my final statement on this weather system as it is not expected to acquire tropical characteristics.

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

IOH 24 Hr Outlook (1200Z Jun 4)...0% chance of subtropical cyclone formation (between the Azores and Canary Islands near 34.5N-21W)


...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 Storm Cristobal...through 66 hours drifts the track northward along the western Yucatan coast region...forecasts acceleration northward across Gulf of Mexico with landfall over southeastern Lousiana by 120 hours. For area of interest #1...shows frontal cyclone shifting south to a position west of the Canary Islands by 60 hours...then shifting east across the northern Canary Islands and losing its identity between the islands and Portugal by 90 hours


0000Z ECMWF Model Run...For Tropical Storm Cristobal...through 72 hours drifts the track northward along the western Yucatan coast region...forecasts acceleration northward across Gulf of Mexico and positioned just south of southeastern Louisiana at 120 hours (shows a potentially strong tropical cyclone at 96 hours). For area of interest #1...shows frontal cyclone shifting south to a position west of the Canary Islands by 48 hours...then shifting east across the northern Canary Islands and losing its identity between the islands and Portugal by 96 hours

0600Z GFS Model Run...For Tropical Storm Cristobal...through 30 hours moves the circulation inland to the northwestern Guatemala/Mexico border where it loses its identity within broad low pressure area to the southeast...through 66 hours lifts broad low pressure area northward across west Yucatan coast while suggesting tropical cyclone formation (not clear if this is the remnants of Cristobal or a second seperate tropical cyclone). Has tropical cyclone shift northward across the Gulf of Mexico and reach the southeast Lousiana coast at 108 hours...then drifts the cyclone westward along the south-facing Lousiana coast through 120 hours. For area of interest #1...shows frontal cyclone shifting south to a position west of the Canary Islands by 48 hours...then shifting east across the northern Canary Islands and losing its identity between the islands and Portugal by 102 hours.


0600Z NAVGEM Model Run...For Tropical Storm Cristobal...through 30 hours moves the circulation inland to the northwestern Guatemala/Mexico border where it loses its identity within broad low pressure area to the southeast...through 66 hours lifts broad low pressure area northward across west Yucatan coast while suggesting tropical cyclone formation (not clear if this is the remnants of Cristobal or a second seperate tropical cyclone). Has tropical cyclone shift northward across the Gulf of Mexico...centered just southeast of Louisiana and south of Mississippi at 120 hours. For area of interest #1...shows frontal cyclone shifting south to a position west of the Canary Islands by 48 hours...then shifting east across the northern Canary Islands and losing its identity between the islands and Portugal by 96 hours.

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