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Hurricane SIMON Forecast Discussion Number 15
2014-10-05 10:42:48| National Hurricane Center (East Pacific)
Issued at 200 AM PDT SUN OCT 05 2014 000 WTPZ44 KNHC 050842 TCDEP4 HURRICANE SIMON DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP192014 200 AM PDT SUN OCT 05 2014 Simon peaked around 0000 UTC based on various satellite intensity estimates and microwave satellite imagery indicating that an eyewall replacement was well underway at that time. Since then, more recent conventional and microwave satellite imagery indicates that the inner-core convection has eroded significantly, especially in the southwestern semicircle, and that the eye is rapidly becoming less distinct. The initial intensity of 100 kt, which could be generous, is based on a blend of subjective and objective satellite intensity estimates from TAFB, SAB, and UW-CIMSS. The initial motion estimate is 320/09 kt. There is no significant change to the previous forecast track or reasoning. A steadily weakening Simon is forecast to move around the western periphery of a deep-layer ridge that extends from central Mexico westward to southern Baja California Sur for the next 48 hours, and then recurve to the northeast as the cyclone comes under the influence of mid-level southwesterly flow ahead of an approaching weak shortwave trough. As the cyclone weakens and becomes more vertically shallow, the system is expected to slow down until it reaches the latitude of recurvature along 24N-25N, after which a gradual increase in forward speed is expected. The official forecast track is just an update of the previous advisory track and is close to the consensus model TVCN. Simon is now located over sub-26C sea-surface temperatures and is heading for cooler water. The cyclone is expected to remain in unfavorable oceanic and thermodynamic conditions for at least the next 72 hours, during which time southwesterly vertical wind shear is forecast to increase to more than 25 kt by 48 hours. These hostile conditions are expected to result in rapid weakening of Simon, with the cyclone becoming a remnant low pressure system by 96 hours, if not sooner. The new intensity forecast is a little lower than the previous advisory, and essentially follows the intensity consensus model IVCN. Even if Simon or its remnant circulation does not make it across the rugged terrain of the Baja California peninsula, deep moisture associated with the cyclone is expected to spread across northern Baja California, northwestern Mexico, and into the U.S. Desert Southwest, which could trigger another heavy rain event in those regions in a few days. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 22.1N 116.7W 100 KT 115 MPH 12H 05/1800Z 23.0N 117.3W 85 KT 100 MPH 24H 06/0600Z 24.0N 117.6W 70 KT 80 MPH 36H 06/1800Z 24.9N 117.5W 55 KT 65 MPH 48H 07/0600Z 25.6N 117.1W 40 KT 45 MPH 72H 08/0600Z 27.6N 115.6W 30 KT 35 MPH 96H 09/0600Z 28.9N 114.3W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 10/0600Z 30.6N 112.8W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Stewart
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Category:Transportation and Logistics