Dave Warren Weather: Typhoon Rammasun Strengthens Rapidly

Rapid Intensification Prior to Landfall

Rammasun went from a Tropical Storm with 60 mph wind to a Typhoon with 125 mph wind in just 36 hours. The storm made landfall in the Central Philippines Tuesday. The satellite loop shows a clear eye develop around a solid area of thunderstorms just before the storm impacts land.

Warm Water with little Wind Shear

Stremlines and contours is what it may look like but this is a map that charts wind shear. The change of wind direction or speed with height can actually rip apart tropical storms. With very low shear and warm water a storm will not be held back from Intensifying.


Highlighted area shows an area with low wind shear. This is the area that Rammasun moved through just prior to landfall in the Philippines.

Water temperatures were just over 85 degrees near the Central Phillipines. This combined with the lack of wind shear led to rapid intensification in the period just prior to landfall.

Just Like Hurricane Humberto

Had to look through a few years of data but remembering where it happened made it a lot easier. Hurricane Humberto went through a similar intensification prior to making landfall in Texas back in 2007.

Date: 12-14 SEP 2007
Hurricane-1 HUMBERTO
ADV  LAT    LON      TIME     WIND  PR  STAT
  1  28.10  -95.20 09/12/15Z   30  1006 TROPICAL DEPRESSION
 1A  28.30  -95.10 09/12/18Z   40  1005 TROPICAL STORM
  2  28.60  -94.90 09/12/21Z   45   999 TROPICAL STORM
 2A  28.80  -94.80 09/13/00Z   45   998 TROPICAL STORM
  3  29.00  -94.60 09/13/03Z   55   995 TROPICAL STORM
  4  29.40  -94.40 09/13/05Z   70   992 HURRICANE-1
  5  29.90  -94.10 09/13/09Z   75   986 HURRICANE-1

The data from the National Hurricane Center shows that the storm went from a depression to a Hurricane in under 24 hours.

Hurricane Humberto Radar just after Landfall

What Does this mean for the Philippines?

The Philippines Government had already ordered evacuations for many coastal areas and issued alerts in the capitol of Manila for typhoon force winds. The storm should lose some intensity over land but is forecast to increase in strength before impacting Vietnam and China this weekend. The storm can easily be tracked from many agencies.