Basement-dwelling pseudo-otaku with a thrill for forecasting on the side.
By: KoritheMan , 2:30 AM GMT on October 29, 2013
Raymond continues to weaken. As of the 2100Z NHC advisory, the following coordinates were given on the cyclone:
Wind: 70 mph, with higher gusts
Location: 16.8°N 116.9°W
Movement: N at 7 mph
Pressure: 993 mb
Satellite estimates have continued to plummet as fast as Dvorak constraints allow, with TAFB and SAB coming in with a mutual 3.0 as of 0z. This suggests that Raymond has weakened since the 21Z NHC advisory, and it will be interesting to see what they assign as the initial intensity during the upcoming 0300Z advisory.
Figure 1. Latest infrared satellite image of Tropical Storm Raymond. Image credit: NOAA's Satellite Services Division (SSD).
Satellite images show that the low-level center is completely exposed to the southwest of the remaining convection which continues to get sheared away due to about 25 kt of southwesterly shear as analyzed by the SHIPS model. The models show the shear increasing further, with water vapor animations continuing to strongly indicate that the winds are more likely to rise to around 35 kt during the next 24 hours. The shear, in combination with sea surface temperatures that are already starting to cool, and increasingly marginal thermodynamic profiles, should act to quickly stop the heartbeat of already half dead Raymond. Given the environment, Raymond is expected to lose its nominal status as a tropical cyclone in roughly 48 hours, but there is of course a decent chance that this will occur in as little as 36 hours. The remnant low is forecast to meander and completely lose its identity over the open Pacific well south of Baja California beyond day four.
With the center now exposed, Raymond's motion is easier to determine, and it appears to be due northward. If not for the lack of convection, there would likely be a more east of north track as of now, but there still appears to be a decent ridge around 850 mb that is preventing Raymond from moving poleward for now. Regardless, Raymond should turn northeastward very soon as the trough appears to be gradually exerting its influence even as far down the troposphere as 850 mb, albeit more slowly than heights above that level. The models continue to agree on this general scenario, with the primary difference being whether or not Raymond makes it above 20N, or remains below that latitudinal line. The GFS ECMWF, and HWRF show Raymond getting above 20N during the next 48 hours, while the GFDL does not indicate Raymond making it quite that far north. Despite the historical reliability of the GFS and ECMWF, I feel the GFDL has a better handle on the situation given the still persistent ridge in the lower troposphere, as well as the hostile conditions that prevail along the forecast track. This leads to my forecast track being a shade south of the current NHC prediction, opting instead to show an eastward drift prior to dissipation in deference to the GFDL.
Intensity forecast and positions
INITIAL 10/29 0300Z 17.1°N 117.0°W 60 KT 70 MPH
12 hour 10/29 1200Z 17.8°N 116.7°W 45 KT 50 MPH
24 hour 10/30 0000Z 18.6°N 116.2°W 35 KT 40 MPH
36 hour 10/30 1200Z 19.3°N 115.7°W 30 KT 35 MPH
48 hour 10/31 0000Z 19.5°N 115.6°W 25 KT 30 MPH...POST-TROPICAL/REMNANT LOW
72 hour 11/01 0000Z 19.5°N 115.4°W 20 KT 25 MPH...POST-TROPICAL/REMNANT LOW
96 hour 11/02 0000Z...DISSIPATED
Figure 2. My forecast track for Raymond.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.
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