MY 2022 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #78
*******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.**********
...FRIDAY AUGUST 19 2022 12:09 AM EDT...
See area of interest #19 section below for more information on the tropical disturbance now currently entering the Bay of Campeche and western Gulf of Mexico waters. The disturbance continues to be monitored for signs of further development before its expected landfall in northeastern Mexico or far southern Texas this weekend.
Elsewhere... the tropical wave of low pressure currently in the eastern tropical Atlantic has lost its low pressure swirl while ingesting the dry saharan air layer located just to the north and therefore tropical cyclone formation of this feature is not expected. Attention now turns to an additional tropical wave of low pressure currently inland over central Africa which has displayed a large area of thunderstorm activity with broad rotation. Should this tropical wave show signs of repelling the dry saharan air layer when it later enters the eastern tropical Atlantic... or if the wave gains support from computer models in the days ahead... will consider adding it as an area of interest for further development in future updates.
New to this site this year... I will be sequentially numbering up areas of interest for possible Atlantic tropical development. In this scheme... will reset back to #1 at the start of next year (January 2023). The current area of interest in this blog post is designated #19 as I designated the other eighteen of this year in previous birdseye view posts on the home page. This scheme is to reduce confusion as Atlantic tropical activity increases during the peak of the hurricane season... when multiple simultaneous areas of interest begin and end which previously required shuffling around the area of interest numbers from update to update.
AREA OF INTEREST #19...The tropical disturbance whose center of rotation has spent much of Thursday afternoon moving west-northwest across the Mexican province of Campeche is now making its way into the Bay of Campeche. As it does so... the central thunderstorm mass and outer bands of activity have largely dissipated... however a skeletal spiral structure of rotating low-level clouds remains on tonight's infrared satellite imagery since the collapse in the thunderstorm activity has only been recent. The disturbance continues to consist of a surface tropical wave of low pressure and overhead upper anticyclonic ridge providing low shear and upper outflow. Going against this disturbance continues to be a lack of computer model support showing development... and the lack of a defined surface circulation below the skeletal spiral cloud bands as seen in NHC TAFB surface analysis and CIMSS 850 mb vorticity product (http://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). Specifically the NHC TAFB shows the nearby tropical wave axis being just to the southeast of the spiral cloud bands...and the CIMSS product shows mid-level rotation to the south of the spiral cloud bands instead of being beneath the spiral. Also noting that surface pressures just northeast of the disturbance... in association with the Gulf of Mexico surface ridge... appears high (1018 mb in the NHC TAFB analysis). As noted in the above birdseye view chart the surface ridge is supported by a zone of convergence between the east side of the overhead upper ridge and west side of a string of lingering upper vorticity to the northeast. Perhaps the surface/mid-level voriticity remais south of instead of below the spiral cloud bands due to the presence of this surface ridge. And perhaps the models refuse to develop this system due to the high surface pressures of the Gulf of Mexico surface ridge... which is expected to persist as the overhead upper ridge and aforementioned upper vorticity string will not be changing their positions during the forecast period. Going for this disturbance is the rather warm water temperatures that lie ahead in the Bay of Campeche and western Gulf of Mexico...and the supportive core of the upper ridge which is producing upper outflow and keeping wind shear over the disturbance low.
Regarding odds of tropical cyclone formation: due to the recent decline in the thunderstorm activity and the list of factors going against this disturbance noted in the prior paragraph (which includes the high surface pressures in the Gulf of Mexico)... relative to special update #77A I have lowered short-term odds of tropical cyclone formation to 50% while maintaining 60% odds for the 48-hour period. I have elected only a cautious shrinkage in development odds as the disturbance still has a healthy skeletal spiral structure... and given the strong positive factors also mentioned in the previous paragraph the skeletal structure could go on to quickly re-fire a thunderstorm complex and go on to develop anyway. Also noting the NHC in their tropical weather outlook raised odds of tropical cyclone formation from 30% to 40% from 2 PM EDT to 8 PM EDT Thursday.
Regarding the track forecast...no changes since special update #77A. The disturbance's current west-northwest track is expected to bend increasingly north while the disturbance rounds the south and west sides of the Gulf of Mexico surface ridge... eventually heading toward a surface ridge weakness now opening up over the central US in association with a frontal low being supported by an upper trough now pivoting into the region from central Canada.
Regarding impacts to land areas...interests in Tamaulipas and southern Texas to the south of Matagorda Bay should monitor the progress of this system. Preparations for possible tropical storm conditions (heavy rainfall with flash flooding potential on both inland and coastal areas... with gusty winds and ocean swells along the coast) may need to start as soon as Friday night should tropical cyclone formation occur within the next 24 hours. Tropical storm conditions are possible later this weekend.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Aug 20)...50% chance of tropical cyclone formation (Bay of Campeche near 20.5N-94.5W)
IOH 48 Hr Outlook (0000Z Aug 21)...60% chance of tropical cyclone formation (Just offshore of Tamaulipas near 23.8N-97.5W)
IOH 72 Hr Outlook (0000Z Aug 22)...0% chance of tropical cyclone formation (Inland over the Texas/Mexico border near 26.1N-98W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Aug 18) CMC Model Run...
**For area of interest #19...no development shown
1200Z (Aug 18) ECMWF Model Run...
**For area of interest #19...no development shown
1800Z (Aug 18) GFS Model Run...
**For area of interest #19...no development shown
1800Z (Aug 18) NAVGEM Model Run...
**For area of interest #19...no development shown