Public advisory[]
TROPICAL STORM LINFA PUBLIC ADVISORY NUMBER 5
WIKI-HURRICANES FORECASTING CENTER
12:00 PM JST FRI JUL 03 2015
...LINFA STRONGER ALTHOUGH DISORGANIZED...
SUMMARY OF 12:00 PM JST...03:00 UTC...INFORMATION
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LOCATION...15.6N 126.2E
CENTER POSITION CONFIDENCE: MEDIUM
ABOUT 355 MI...570 KM ENE OF MANILA, PHILIPPINES
MAXIMUM SUSTAINED WINDS...50 KT...60 MPH...95 KM/H
MINIMUM BAROMETRIC PRESSURE...998 MB...29.47 INCHES
PRESENT MOVEMENT...WNW AT 6 KT...7 MPH...11 KM/H
DISCUSSION AND 48-HOUR OUTLOOK
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At 12:00 pm JST, the center of Tropical Storm Linfa was situated near 15.6N 126.2E, or about 355 miles (570 km) east-northeast of Manila, Philippines. Maximum sustained winds were 50 knots (60 mph, 95 km/h), with higher gusts. The minimum barometric pressure was 998 millibars (hPa; 29.47 inHg), and the cyclone was tracking west-northwest at 6 knots (7 mph, 11 km/h). Atmospheric conditions are expected to be marginally conducive for slow development as this sytem tracks slowly toward the west-northwest or northwest over the next few days. Linfa is expected to begin weakening as it executes a turn toward the northeast at the end of the forecast period.
NEXT ADVISORY
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Next complete advisory at 6:00 pm JST.
$$
Forecaster TAWX14
Discussion[]
TROPICAL STORM LINFA DISCUSSION NUMBER 5
WIKI-HURRICANES FORECASTING CENTER
12:00 PM JST FRI JUL 03 2015
Tropical Storm Linfa continues to be a disorganized cyclone this evening. Visible satellite animations reveal a low-level circulation that is partially exposed on the northern edge of a large convective mass. However, banding features have become slightly more distinct since the previous advisory. In addition, an 0134z ASCAT pass indicated a sizeable region of 45kt winds and small pocket of 50kt winds within the southeastern quadrant of the system. Considering the documented conservative bias with the instrument, the initial intensity has been raised to 50kt. This is in disagreement with recent satellite estimates of T2.5/35kt from SAB and JTWC, and T2.4/34kt from UW-CIMSS ADT.
Linfa has been tracking steadily west-northwest over the coming hours. This motion is expected to continue for the next 48 hours under the influence of the western periphery of a subtropical ridge to the cyclone's northeast. This track is well supported by reliable global modelling. The tricky part of the forecast comes after 48 hours, when Linfa is expected to approach the coast of Luzon. Recent runs of the GFS have indicated a more southern track with the cyclone, indicating landfall along the coast of the northern Filipino island; the ECMWF, on the other hand, continues to indicate that the center of the system will remain offshore. Joining the GFS are recent runs of the HWRF, which have also pointed toward a landfall in Luzon. As such, the updated forecast is similar to the previous one and shows Linfa skirting the northern portions of Luzon. The outcome remains equally conflicting thereafter, with the GFS/HWRF indicating a stall and the ECMWF indicating a slow northeastward track. Given what should be some semblance of a weakening to the system's northeast, more weight has been given to the ECMWF after 48 hours. By the end of the forecast period, if the system does indeed track northeastward, interaction with what is expected to be a powerful Chan-hom may muddle the situation even further. Needless to say, this is a low confidence track forecast.
Linfa continues to be affected by a strong 20 to 30 knots of wind shear on the east side of broad anticyclonic flow to the system's west. This shear is expected to only slightly relent over the coming days, and the end result for Linfa should be strictly a slow intensification trend despite runs from the HWRF which indicate substantial strengthening over the next 48 hours. Thereafter, the intensity forecast becomes complicated. As a result of the aforementioned stall as depicted by the HWRF and GFS, both models steadily weaken Linfa inland until dissipation. The ECMWF, on the other hand, maintains a steady-state cyclone as it moves into the Luzon Strait and subsequently recurves northeast. With more weight placed on the ECMWF, the updated intensity forecast indicates steady weakening after 48 hours. Much like the track forecast, this is also a low confidence intensity forecast.
INIT 03/0300Z 15.5N 127.4E 50 KT 60 MPH
12H 03/1200Z 16.3N 126.8E 50 KT 60 MPH
24H 04/0000Z 16.9N 125.4E 55 KT 65 MPH
36H 04/1200Z 17.3N 124.7E 60 KT 70 MPH
48H 05/0000Z 17.5N 123.9E 65 KT 75 MPH...NEAR LUZON
72H 06/0000Z 17.9N 121.1E 55 KT 65 MPH...OVER LUZON
96H 07/0000Z 18.9N 120.9E 45 KT 50 MPH...OVER LUZON STRAIT
120H 08/0000Z 21.2N 122.3E 40 KT 45 MPH
$$
Forecaster TAWX14