MY 2021 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #50
*******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 JULY 14 2021 10:49 PM EDT...
Satellite image as of 2050Z. Areas of interest circled in yellow are not mentioned in the NHC tropical weather outlook. Areas circled in a green dashed line are in the NHC 5-day tropical weather outlook. Areas circled in a solid green line are in the NHC 2-day tropical weather outlook:
NHC TAFB Surface Analysis 1800Z:
GFS Model Upper-Level Winds 1800Z:
See area of interest #1 section below for an update on the potential for tropical development in northwest Atlantic waters to the north of Bermuda. Elsewhere…tropical development in the Atlantic basin has been suppressed by low-latitude (southern located) upper vorticity toward the west side of the basin and dry Saharan air toward the east side of the basin. However some recent model runs suggest in about six days a strong tropical wave of low pressure from Western Africa will emerge into the eastern tropical Atlantic…with some potential for this wave to develop.
AREA OF INTEREST #1…A cloud swirl frontal surface low pressure in the open northwest Atlantic remains supported by split flow upper divergence between the west side of the upper trough in the north Atlantic and east side of the sprawling upper ridge in the west Atlantic…and is currently located near 37N-59.5W. A surface ridge to the north has pushed the surface low pressure west-southwest…and will soon push the surface low further west a little past 60W longitude where the water temps are slightly warmer….and a little closer to the center of the sprawling upper ridge where wind shear is low and upper outflow is high.
I have nudged the forecast positions in my updated outlook below to the south and east due to the current position of the surface low. Although the surface low has not yet fired much thunderstorm activity since it’s birth yesterday…I agree with the NHC in still having some odds of tropical cyclone development above zero (at 10%) as the surface low has yet to reach the warmer 26 deg C water that lies near and just west of 60W longitude. By 48 hours I end the outlook (bring development odds to 0%) as the forecast track is expected to bend north while the surface low rounds the west side of the steering surface ridge…which will take the surface low to cooler water.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Jul 16)…10% chance of tropical cyclone formation (northwest Atlantic near 37.5N-60.5W)
IOH 48 Hr Outlook (0000Z Jul 17)…0% chance of tropical cyclone formation (northwest Atlantic near 41N-58.8W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z CMC Model Run...
**For area of interest #1...surface low turns north and weakens to a surface trough near 42N-54W at 66 hours.
1200Z ECMWF Model Run...
**For area of interest #1…surface low turns north and weakens to a surface trough near 41N-57.5W at 48 hours.
**Large and strong tropical wave forecast to emerge from Western Africa at 144 hours…low pressure spin of the wave located just west-southwest of the Republic of Cabo Verde Islands at 168 hours.
1800Z GFS Model Run...
**For area of interest #1...surface low turns north and weakens to a surface trough near 40.5N-59.5W at 42 hours.
1800Z NAVGEM Model Run...
**For area of interest #1...surface low turns north and weakens to a surface trough near 41N-59W at 36 hours.
**Large and strong tropical wave forecast to emerge from Western Africa at 144 hours…low pressure spin of the wave located just west of the Republic of Cabo Verde Islands at 168 hours.