Tag Archives: 91E

Tropical Depression 2E Prompts Tropical Storm Watch By Mexico

The National Hurricane Center designated former Invest 91E as Tropical Depression 2E and the government of Mexico issued a Tropical Storm Watch for the portion of the coast from Salina Cruz to Puerto Escondido.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression 2E was located at latitude 13.9°N and longitude 97.8°W which put it about 250 miles (400 km) southeast of Acapulco, Mexico.  The depression was moving toward the northeast at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

Bands of showers and thunderstorms developed closer to the center of a broad area of low pressure previously designated as Invest 91E on Wednesday morning.  The improved organization prompted the National Hurricane Center to classify the system as Tropical Depression 2E.  Several bands of showers and thunderstorms were revolving around a tighter center of circulation.  Additional bands of showers and thunderstorms were strengthening in the outer portions of the circulation.  Thunderstorms in the inner part of the circulation were beginning to generate upper level divergence which was pumping out mass to the north and west of the depression.

Tropical Depression 2E will be moving through an environment that will be favorable for intensification.  It will be moving over water where the Sea Surface Temperature is 30°C to 31°C.  An upper level ridge centered east of the depression will generate southerly winds which will blow toward the top of the circulation.  Those winds will generate some vertical wind shear, but the shear will not be strong enough to prevent strengthening.  The circulation around the upper level ridge could actually enhance upper level divergence to the north of the depression.  Tropical Depression 2E is likely to intensify into a tropical storm during the next several days.

A subtropical high east of the depression is steering the system slowly toward the northeast.  A slow northerly motion is forecast for the next day or two.  Forecast guidance from the numerical models diverges when the system approaches Mexico.  Some models continue to move the depression inland over Mexico.  Other models suggest that the steering winds will weaken and that the system will stall before it reaches the coast.  The official forecast from the National Hurricane Center has the depression stalling very near the coast and then turning westward during the weekend.

Bands of rain in the outer part of the circulation are already moving over the coast.  Tropical Depression 2E will produce locally heavy rainfall over parts of southern Mexico and there is the potential for dangerous flash floods.

Invest 91E Slowly Organizing South of Mexico

A broad area of low pressure designated as Invest 91E slowly organized south of Mexico on Tuesday.  At 8:00 p.m. EDT on Tuesday the center of Invest 91E was located at latitude 13.7°N and longitude 97.9°W which put it about 220 miles (350 km) south-southeast of Acapulco, Mexico.  Invest 91E was moving toward the north-northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

Invest 91E consisted of a broad area of low pressure located south of Mexico.  The Invest did not have a well organized center of circulation.  Instead there was a broad area of counterclockwise rotation.  Many of the thunderstorms were in bands in the outer periphery of the circulation.  A few thunderstorms were beginning to form closer to the center and there were signs that some bands of showers were beginning to organize nearer to the core of the system.

Invest 91E will be moving through an area that will be favorable for development of a tropical cyclone.  It will move over water where the Sea Surface Temperature is near 30°C.  Invest 91E will be moving underneath the western portion of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of the circulation.  The southerly winds will cause some vertical wind shear.  However, the effects of the shear could be offset by upper level divergence created by the upper level ridge.  Invest 91E has a good chance to develop into a tropical depression and the National Hurricane Center is indicating that there is a 70% probability of a depression forming during the next 48 hours.

A subtropical ridge east of Invest 91E is steering the system slowly toward the north-northeast.  A general northerly motion is expected to continue for another 24 to 48 hours.  On its anticipated track Invest 91E will approach the southern coast of Mexico.  It could bring locally heavy rain when the outer bands on the northern side of the circulation move over land.