Mirinae has been intensified into Typhoon and tracked westward to west-northwestward in the past few hours. It is expected to make landfall on the northern Philippines and will bring threat to Philippines.
Track Analysis
Typhoon Mirinae, located about 750 kilometers north of Yap, is forecast to move west. From the numerical model, the strength of the high pressure steering ridge will be invariant and it is steering Mirinae westward within few days and will be approaching the eastern coast of Luzon.
Strength Analysis
As mentioned by JTWC, the strong zonal flow across southern Japan in the upper level becomes the primary mechanism for poleward outflow (shown in fig1). Also, there is an upper level anticyclone located to the east of the system which will enhance the equaterward outflow. Therefore, the upper level divergency channel has been maintained after the lifting out of the mid-latitude trough.
Figure 1 - Wind Field in Layer 200hPa of ECMWF model
The atmosphere allow the strengthening of Mirinae and it is forecast to become a Category 3 Typhoon before landfall with the maximum wind speed near 190kph in one minute average. The circulation of Mirinae will become more organized and the outer rainbands will effect the eastern Luzon on about Friday.
Organization Cyclone Information:
+ HKO(10-min avg): TY120 km/h + JMA(10-min avg): TY145 km/h + CWB(10-min avg): TY125 km/h
+ JTWC#10(1-min avg): TY160 km/h
Appendix
Figure 2 – Sea level Pressure of ECMWF model after 24 hrs
Figure 3 – Sea level Pressure of ECMWF model after 72 hrs
Figure 3 – Geopotential 500 hPa of ECMWF model after 72 hrs
From the images above, it reveals that Mirinae keep intensifying. Also, it tracks westward beneath the subtropical ridge before coming ashore near Philippines.
The severe tropical storm Lupit, located about 520 kilometers south-southwest of Okinawa, is expected to move away from the northern Philippines with low speed. The scenario has changed a little bit. As Lupit started tracking northeast, it is no longer to move further close to the extreme northern Luzon and make landfall on Taiwan. It is now forecasted to be persistently steered by the weak extend of high pressure ridge located to the east of it. And in the long-range forecast, it will enter the mid-level westerly wind flow and start accelerating to the east.
Synoptic Circulation Analysis
From the latest Korea Meteorological Administration’s 500hPa analysis chart(shown in figure 1), delivered at 2009-10-24 12:00 HKT, there is a large-scale polar vortex over Siberia(西伯利亞極地渦旋), causing the cold and dry air mass in the vicinity of it to flow further south. Therefore, there is significant temperature gradient over the northern China(shown in figure2).
There was a nearly-omega blocking system (阻塞形勢) in the mid-latitudes(shown in figure 3). The blocking high (阻塞高壓) was built near KamchatkaPeninsula (勘察加半島) due to the strong warm advection (暖平流). The westerly jet flow bypass the stable blocking high and divided into northern as well as southern air flows. It contributes to the vorticity advection (渦度平流) to the northern blocking high and helps the building and maintaining of long-wave low pressure trough (長波槽). As the blocking high was stably located near KamchatkaPeninsula, the trough kept stationary with the base of it reached over Taiwan. The building of this blocking high is the explanation to the northeastern track of Lupit.
Figure 3 –Korea Meteorological Administration’s 500hPa analysis chart at
2009-10-23 00:00 HKT
However, from the latest Korea Meteorological Administration’s 500hPa analysis chart(shown in figure 1), the blocking high seems “breaking down”, causing the next long-wave trough adjustment in the mid-latitudes (長波調整).
Strength Analysis
Based on the synoptic circulation analysis above, the dry and cold air will feed into the weakening circulation system until the next long-wave trough adjustment. The animated infrared imagery shows continued weakening of deep convection. Although the mid-level trough helped to strengthen the system’s poleward outflow, the core of Lupit will still be deteriorating under these unfavorable conditions with the maximum wind speed not exceeding 100km/h in 10-min average.
It is forecasted that Lupit will failed to regain much strength after the next long-wave trough adjustment as it will enter an area of increasing wind shear due to the strong upper-level winds.
It is expected that Lupit will bring minimal damage to the coastal areas of extreme northern Luzon and Taiwan. It is visible in the ensemble tropical rainfall potential chart (shown in figure 4 and 5), the outer rainbands will not spreading across the Philippines and Taiwan and the coverage of the rainbands keep decreasing.
Figure 4 –ensemble tropical rainfall potential chart for rainfall >25mm with 0-6hr forecast period
Figure 5 –ensemble tropical rainfall potential chart for rainfall >25mm with 12-18hr forecast period
Track Analysis
Lupit is expected to be steered northeast by the influence of the weak extend of high pressure ridge and embedded in the westerly mid-level trough which will cause it to move northeast to east with acceleration. For this movement, the core shall pass within 400km to the south of Okinawa. However, it is expected that Lupit will bring only light rainfall with strong or gale wind to the region.
There is another scenario for the track of Lupit. It has the potential to move equaterward after the next long-wave trough adjustment with the base of trough move across Lupit. However, it leads to the blocking of divergence channel and there will be again the intrusion of dry air in the mid and upper levels. For this scenario, it has low probability to happen.
Organization Cyclone Information:
+ HKO(10-min avg): STS90 km/h + JMA(10-min avg): STS90 km/h + CWB(10-min avg): STS90 km/h
+ JTWC#41(1-min avg): STS95 km/h
After crushed by Typhoons Ketsana and Parma, the northern Philippines is now suffer another predicament.The tropical storm Lupit has its probability to bring a heavy damage to the northern Philippines, especially Cagayan. Although the new numerical analysis reveal that Lupit will recurve and the northern Philippines can be spared on a direct hit, the outer rainbands will still contribute to life-threatening floods and landslides in Philippines.
Tropical storm Lupit, located about 560 kilometers north-northeast of Manila, has been constantly decelerating in the past few hours. As the influence of the mid-level low pressure trough, reached just above Taiwan(shown in figure1), the high pressure steering ridge remained in the west pacific will be weakened. Under those conditions, there is high possibility that Lupit might track north slowly and approach Taiwan.
Figure 1 - Wind Field in Steering Layer 500hPa of ECMWF
Enhanced by the mid-level low pressure trough, dry and cold air will flow further south and the circulation of Lupit will continue to weaken under these unfavorable conditions. Although Lupit is expected to track towards Taiwan, the rainbands of Lupit will weaken and bring only moderate rains to Taiwan.
Organization Cyclone Information:
+ HKO(10-min avg): STS105 km/h + JMA(10-min avg): STS111 km/h + CWB(10-min avg): STS108 km/h + JTWC#38(1-min avg): STS101 km/h
