*******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...SUNDAY AUGUST 25 2024 12:15 PM EDT...
Surface and upper air charts have now been added to the satellite image. The charts were not originally included in this update to allow the update to be released in a timely manner.
For the disturbance moving into the Florida peninsula... tagged as area of interest #18 in this update... the small cloud swirl has made landfall on the southeast coast of the peninsula just east of Lake Okeechobee and still lacks thunderstorms on colorized infrared satellite. To the southwest of the swirl... scattered thunderstorms have recently increased across the Florida Keys.
...SUNDAY AUGUST 25 2024 5:35 AM EDT...
Satellite image from 0350Z earlier this evening… the disturbance that is tagged area of interest #18 in this blog post is circled in yellow:
Within the next few days... the area in the Atlantic basin that is the most likely to see possible tropical development remains the Gulf of Mexico... see area of interest #18 section below for more information.
Elsewhere... satellite imagery shows a vigorous tropical wave of low pressure that is currently entering the eastern tropical Atlantic from the west coast of Africa. The current eastern Atlantic upper vorticity... and a portion of the current northeast Atlantic upper trough... are forecast to descend southward overtop this tropical wave while pushed by the current sprawling east Atlantic upper ridge... with the overhead wave of upper vorticity suppressing outflow needed for tropical development. Therefore this tropical wave is not forecast to develop.
AREA OF INTEREST #18... The weak tropical disturbance that was over the western Bahamas was spotted on visible satellite before sunset… and with recent nighttime infrared satellite… as a small cloud swirl now between southeast Florida and the Bahamas. The recent NHC TAFB surface analysis from 1800Z also analyzed a surface trough of low pressure in this area… therefore for the updated outlook shown below I have initialized the disturbance at this position. Through the next 48 hours steering surface ridging remains intact to the north of the disturbance while becoming supported by the western convergence zone of the current eastern Canada upper trough that will dive southeast around the central North America upper ridge... resulting in the disturbance shifting west across the Florida peninsula and into the Gulf of Mexico. During this time the central North America upper ridge will also push the current central Gulf of Mexico upper trough/vortex westward into Texas... with this disturbance staying aligned with an upper anticyclone (favorable low shear/outflow environment) that manifests in the relatively higher upper pressures between the southeastward-diving eastern North America upper trough and Texas upper trough/vortex. However I currently assign a low 10% chance of tropical cyclone formation as the disturbance remains weak and lacks computer model support showing development… and I have delayed the timing of the 10% odds to give time for the initially weak disturbance to become more established first. For the longer-range... 72 to 120 hours... the next mid-latitude upper troughs approaching from western North America are currently forecast to weaken the steering surface ridge which results in a slow-down and northward turn across Louisiana in the current forecast track shown below. The northward turn may also be aided by the Texas upper trough/vortex getting kicked back east toward this disturbance by the approaching mid-latitude upper troughs... which could result in some increase in shear or outflow blockage from the west but at the same time possibly enhancing the disturbance with its eastern divergence zone. Thus I keep 10% odds of development through land all time (96 hours).
If the disturbance develops thunderstorm activity under the forecast favorable upper winds… while its in the Gulf of Mexico… then southeastern Texas and/or Louisiana may see a round of heavy rainfall from this system by the middle of this upcoming week.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Aug 26)... 0% chance of tropical cyclone formation (just offshore of the southwest Florida peninsula coast near 26N-82.5W)
IOH 48 Hr Outlook (0000Z Aug 27)... 0% chance of tropical cyclone formation (eastern Gulf of Mexico near 26N-85.5W)
IOH 72 Hr Outlook (0000Z Aug 28)... 10% chance of tropical cyclone formation (north-central Gulf of Mexico near 26.5N-90W)
IOH 96 Hr Outlook (0000Z Aug 29)... 10% chance of tropical cyclone formation (just offshore of southwestern Louisiana near 28N-93.5W)
IOH 120 Hr Outlook (0000Z Aug 30)… 0% chance of tropical cyclone formation (southeastern Arkansas near 33.8N-92W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 8 PM EDT***************************
Not in the official outlook
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Aug 24) CMC Model Run...
**For area of interest #18... no development shown
**Tropical wave currently over western Africa emerges into the tropical Atlantic at 30 hours and develops into a tropical low near 11.5N-38.5W by 150 hours… tropical low reaches 12N-40.2W by 168 hours
1200Z (Aug 24) ECMWF Model Run...
**For area of interest #18... no development shown
1800Z (Aug 24) GFS Model Run...
**For area of interest #18... no development shown
1800Z (Aug 24) NAVGEM Model Run...
**Model run not available at above-mentioned source
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