Typhoon Maysak moved into an area of drier air and weakened to a tropical storm on Saturday before making landfall in Luzon.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Maysak was located at latitude 16.7°N and longitude 122.0°E which put it about 20 miles southeast of Cauayan and about 160 miles northeast of Manila, Philippines.  Maysak was moving toward the northwest at 12 m.p.h.  The maximum sustained wind speed was 50 m.p.h. and there were gusts to 65 m.p.h.  The minimum surface pressure was 989 mb.

Maysak is moving inland over Luzon.  The combination of the mountains in northern Luzon and drier air will cause Maysak to continue to weaken.  Even as the wind speeds decrease, air flowing up the sides of mountains will enhance the rainfall and create the potential for localized flooding and mudslides.  If a closed circulation still exists, it will be much weaker when it emerges over the South China Sea on Sunday.

Typhoon Maysak maintained its heading toward Luzon on Friday and it is about 24 hours away from making landfall.  At 5:00 p.m. EDT on Friday the center of Typhoon Maysak was located at latitude 14.6°N and longitude 127.2°E which put it about 200 miles east-northeast of Catanduanes Island and about east-southeast of Luzon.  Maysak was moving toward the west at 15 m.p.h.  The maximum sustained wind speed was 95 m.p.h. and there were gusts to 115 m.p.h.  The minimum surface pressure was 963 mb.

An upper level trough that was causing vertical wind shear over Maysak moved eastward on Friday and the wind shear over the typhoon decreased.  Infrared satellite imagery indicates that more convection developed near the core of Maysak and the upper level divergence has increased in recent hours.  The additional convection appears to have slowed the weakening of the circulation.  Maysak will remain over warm Sea Surface Temperatures as it approaches Luzon and so it will likely still be a typhoon when it makes landfall there.  If new thunderstorms continue to develop near the center of circulation, then some intensification may be possible before landfall.

A subtropical ridge is steering Maysak toward the west-northwest and that motion is expected to continue.  On the projected track Maysak would make landfall in Luzon in 24 to 36 hours.  It has the potential to bring strong winds and locally heavy rain to parts of Luzon.  The locally heavy rain will also create the conditions that could produce mudslides in some areas.

Typhoon Maysak weakened slowly on Thursday as it moved in the direction of Luzon.  At 11:00 p.m. EDT on Thursday the center of Typhoon Maysak was located at latitude 14.3°N and longitude 130.6°E which put it about 420 miles east of Catanduanes Island and about 580 miles east-southeast of Luzon.  Maysak was moving toward the west-northwest at 11 m.p.h.  The maximum sustained wind speed was 110 m.p.h. and there were wind gusts to 130 m.p.h.  The minimum surface pressure was 948 mb.

An upper level trough passing north of Maysak is generating vertical wind shear which is causing the typhoon to weaken slowly.  The western side of the trough contains some drier air which is also getting into the circulation of Maysak.  The drier air is reducing the amount of latent energy available to maintain the circulation.  So, even though Maysak is still over warm Sea Surface Temperatures it is slowly weakening.  The wind shear may decrease after the upper level trough moves east of Maysak, but as the typhoon moves further west, it will still encounter drier air.  As a result, Maysak it expected to continue to slowly weaken.

A subtropical ridge is steering Maysak in a west-northwesterly direction.  The upper level trough has temporarily weakened the ridge and Maysak is moving a bit more toward the northwest.  After the upper level trough moves east of the typhoon, it is expected to resume a west-northwesterly motion.  The expected track would bring Maysak close to Luzon in 36 to 42 hours.  Maysak is expected to be a low end typhoon or strong tropical storm when it nears Luzon.  It will be capable of producing some stronger winds and locally heavy rainfall as it moves across Luzon.

Typhoon Maysak weakened below Super Typhoon intensity on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typoon Maysak was located at latitude 12.6°N and longitude 133.5°E which put it about 300 miles northwest of Yap and about 780 miles east-southwest of Luzon.  Maysak was moving toward the west-northwest at 10 m.p.h.  The maximum sustained wind speed was 135 m.p.h. and there were wind gusts to 160 m.p.h.  The minimum surface pressure was 937 mb.

Maysak appears to have gone through an eyewall replacement cycle on Wednesday.  A rainband wrapped around the existing eyewall to create to concentric eyewalls.  As more air started to converge and rise in the outer eyewall, the inner eyewall which had the stronger winds weakened.  As the inner eyewall dissipated, the core of Maysak became enlarged and it now has an eye with a diameter of 32 miles.  The maximum wind speed decreased as part of the eyewall replacement process.  If the current eye were to shrink, the wind speed could increase again because it is still over warm Sea Surface Temperatures.  However, as Maysak moves toward the west-northwest it is moving toward an area where the upper level winds are stronger.  An upper level trough located northwest of Maysak is generating stronger upper level winds, which will increase the vertical wind shear.  Maysak could intensify on Thursday, but the wind shear is expected to weaken it during the next several days.

A subtropical ridge is steering Maysak toward the west-northwest.  The upper level trough is expected to make it move a little more toward the north during the next 24 to 48 hours.  On its expected track, Maysak could be approaching Luzon in about 60 hours.  Maysak is expected to still be a typhoon when it approaches Luzon.  It could bring strong winds and locally heavy rains.

The core of Super Typhoon Maysak passed north of Yap on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Super Typhoon Maysak was located at latitude 10.7°N and longitude 137.2°E which put it about 90 miles north-northwest of Yap and about 1000 miles east-southeast of Luzon.  Maysak was moving toward the west-northwest at 13 m.p.h.  The maximum sustained wind speed was 160 m.p.h., which made Maysak the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  There were gusts to 195 m.p.h. and the minimum surface pressure was 918 mb.

Maysak continues to exhibit a very impressive structure.  It is very symmetrical and there is strong upper level outflow in all directions.  Some satellite imagery suggests the circulation may have developed concentric eyewalls and that could mean an eyewall replacement is underway.  If so, the intensity could fluctuate while the inner eyewall weakens and the inflow becomes focused on the outer eyewall.  The overall environment around Maysak is very supportive of an intense tropical cyclone.  The upper level winds are relatively light and it is over warm Sea Surface Temperatures.  Maysak could maintain super typhoon intensity for another day or two.  It could move into an area of stronger upper level winds in several days, which would increase the vertical wind shear.

A subtropical ridge is expected to continue to steer Maysak toward the west-northwest.  On the projected track, Maysak could approach Luzon in about four days.  Even if it weakens, it is likely to be a typhoon when it nears the northern Philippines.  It has the potential to bring strong winds and locally heavy rains.

Maysak intensified rapidly on Monday and it is near Super Typhoon intensity.  At 11:00 a.m. EDT on Monday the center of Typhoon Maysak was located at latitude 9.6°N and longitude 142.5°E which put it about 300 miles east of Yap and about 1450 miles east-southeast of Luzon.  Maysak was moving toward the west-northwest at 14 m.p.h.  The maximum sustained wind speed was 140 m.p.h. and there were gusts to 170 m.p.h.  The minimum surface pressure was 929 mb.

Maysak moved into an area of light upper level winds on Monday, which allowed the well-developed upper level divergence to pump out mass in all directions.  As a result, the surface pressure decreased rapidly and the wind speed increased quickly.  The circulation is very symmetrical and Maysak has a tight inner core.  The eye is exhibiting a stadium effect on visible satellite images which is indicative of a very strong tropical cyclone.  Maysak continues to move over warm Sea Surface Temperatures and it could intensify into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  When tropical cyclones get as strong as Maysak is, they often go through eyewall replacement cycles which result in periodic fluctuations of intensity.  On its west-northwesterly track Maysak will gain latitude and it could move into an area of stronger vertical wind shear in 24 to 48 hours.  Increased wind shear would weaken it.

A strong subtropical ridge is steering Maysak toward the west-northwest and that motion is expected to continue in the short term.  The ridge may weaken somewhat in about 24 hours and that would allow Maysak to move in a more northwesterly direction for a day or two.  Later in the week a subtropical ridge is expected to build again and steer Maysak more toward the west again.  On its projected track, the center of Maysak would pass north of Yap in about 24 hours.  However, residents should monitor the typhoon closely in case it takes a more southerly track which would bring the core of stronger winds closer to Yap.  Over the longer term, Maysak could approach Luzon and the northern Philippines in five or six days and it could still be a typhoon at that time.