TROPICAL STORM FORMATION: JOAQUIN, 90L, CATL DISTURBANCE
ALL forecasts contained on this site, are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.
*NOTE: In the TROPICAL STORM FORMATION line above, probabilities are for during the next 5 day period. My personal probability will be listed as either NONE, MONITORING or PROBABLE. This does not necessarily mean something will develop, but that certain forecast conditions are likely to be present, for development. Once NHC products become available, then the appropriate probability and percentage will be used.
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Current Storm Total for 2015:
TOTAL STORMS: 10
INTENSE HURRICANES: 2
U.S. LANDFALLS: 2
StormW’s Seasonal Forecast:
TOTAL STORMS: 8
INTENSE HURRICANES: 1
Good evening everyone!
JOAQUIN remains a powerful CATEGORY 4 Hurricane on the Saffir-Simpson Hurricane Wind Scale this evening. As of the 8:00 p.m. intermediate advisory from the NHC, the following was available on Hurricane JOAQUIN:
5:00 PM EDT Sat Oct 3
Location: 27.3°N 69.6°W
Moving: NE at 17 mph
Min pressure: 937 mb / 27.67 in
Max sustained: 145 mph
HURREVAC NHC TRACKING MAPS:
Analysis of satellite loop imagery shows a very well defined CDO, with a very tight symmetry. It is noted however, that banding appears confined to the eastern semi-circle of the hurricane. Analysis of the current wind shear product indicates this is being caused by the upper level pattern, with an outflow channel noticed from the NE, around toward the south, around the eastern periphery of the hurricane. Current shear values shown are around 30 knots…however this doesn’t appear to be affecting the hurricane, at least at this moment. IF these shear values are the beginning of the forecast trend, then I expect Joaquin to begin to slowly weaken per the NHC intensity forecast. There is a discrepancy between the 12Z forecast shear graphic, which shows an upper level anticyclone remaining over JOAQUIN for the next 48-72 hours (based on forecast track), and the numerical guidance of 6 global models, which indicate shear to remain steady up to 48 hours from 12Z, with it dropping slightly for 12 hours, then increasing beyond that. Based on the numerical guidance, and premise of SST’s becoming cooler (albeit I am more in the camp that it’s more a loss of OHC), JOAQUIN should weaken as per the NHC forecast. This weakening trend is indicated by the 18Z Intensity Forecast.
FORECAST POSITIONS AND MAX WINDS
INIT 03/2100Z 27.0N 70.5W 130 KT 150 MPH
12H 04/0600Z 29.0N 68.7W 125 KT 145 MPH
24H 04/1800Z 31.5N 67.0W 110 KT 125 MPH
36H 05/0600Z 33.7N 66.0W 95 KT 110 MPH
48H 05/1800Z 36.0N 64.0W 80 KT 90 MPH
72H 06/1800Z 40.0N 56.0W 70 KT 80 MPH
96H 07/1800Z 45.0N 40.0W 60 KT 70 MPH…POST-TROP/EXTRATROP
120H 08/1800Z 50.0N 25.0W 60 KT 70 MPH…POST-TROP/EXTRATROP
The hurricane is moving toward the NE, due to a combined factor of being embedded in a weakness, and the force of the trof to the west, advecting eastward. I agree with the NHC discussion, in that JOAQUIN may bend slightly more toward the north in about 24 hours, as the trof continues eastward. The orientation of the trof, should change the deep layer flow slightly to allow this bend. Beyond that time frame, a turn back toward the NE should occur as the system becomes embedded in the westerlies. Note that there may be some slight fluctuations in track, depending on the actual orientation of the approaching trof. For all intents and purposes, I don’t see any major shift in track, based on forecast steering currents, and global model solutions at the moment. There has been a vast amount of data from extra NWS balloon launches, and from the NOAA G IV flights. This has resulted in a better forecast track consensus.
A Tropical Storm Warning is in effect for… * Bermuda A Hurricane Watch is in effect for… * Bermuda
A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. For Bermuda, the tropical storm conditions are expected within the next 24 to 36 hours.
A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous.
Based on these watches and warnings, residents of the island of Bermuda should complete preparations as soon as possible.
I will continue to monitor JOAQUIN for any significant changes.
Elsewhere, INVEST 90L, east of JOAQUIN, has shown no signs or organization. Based on the numerical shear forecast, wind shear is forecast to diminish, with upper level winds becoming conducive. However, this is forecast to be very brief , with a time span of 12, maybe 18 hours at best. Some organization MAY OCCUR, however as JOAQUIN passes closer to this area, wind shear from the outflow of the hurricane, and sinking air should stop any further organization of 90L.
I am also monitoring an area of disturbed weather in the CATL, located near 10N;37W. Analysis of satellite loop imagery indicates a slight increase in convection over the past few hours, with cloud tops having become colder over the last 2 hours.
The current shear pattern shows upper level winds to be marginal to only slightly favorable at the moment. The current shear forecast indicates upper level winds should become more conducive in about 24 hours, through 66 hours. This may be enough for us to see some slow organization of this area, before upper level winds become unfavorable thereafter. I will continue to monitor this area for any significant changes and further development.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS