Tropics

Watching Invest 96L Over The Northeast Carribean

Miguel Pierre Tropics, Uncategorized

Tropical wave 96L is currently moving west-northwest over Puerto Rico this morning. Another reconnaissance flight is scheduled to fly into the system this afternoon. But it is difficult to discern a closed surface circulation with surface observations and satellite imagery this morning.  Strong shear from upper-level trough over the Western Atlantic is enhancing a large area of convection that stretches from the Northeast Carribean Sea to the Southwest Atlantic. This shear along with some land interaction with Puerto Rico and Hispaniola, will likely inhibit further development into a tropical storm through the day tomorrow.

wg8shr15zOn Sunday this system will steered northward into a weakness in ridge over Western Atlantic. At this point, the environment may become more favorable for further development. It will be over warmer waters and the current trough may lift out enough for shear to relax. After this period, the track becomes more uncertain. Another trough will be digging over the Western Atlantic. Some models show this trough fully capturing 96L and quickly recurve it out to sea. Other models show this trough leaving behind 96L and turn it back towards the west or northwest again. However, this would likely be temporary as most models also show a strong ridge building over the Eastern US next week,  that would block further movement west or northwest from 96L.

aal96_2014082212_track_early

Overall in my opinion, the pattern doesn’t look favorable 96L to make landfall along the East coast as significant tropical system.  Tropical storms and hurricanes often take the path of least resistance. Which appears to be over the Western Atlantic next week, between stronger blocking ridge over portions of the Eastern United States and over the Central Atlantic. However, if next week’s trough to be not as deep or more progressive, this could more allow high pressure to build over the Northwest Atlantic, forcing a track closer to East Coast.  Assuming the environment becomes favorable enough for tropical storm to form. At this time, this scenario has a very small chance of happening. But everyone along East Coast, particularly from the Carolinas to New England still need to monitor this storm. Whether not this system threatens the US, large swell from this storm could impact East Coast next week. Another update, will come if they are any major changes or upgrade to tropical storm.

Hurricanes Iselle and Julio Threaten Hawaii

Miguel Pierre Tropics

Usually we are talking hurricanes in the Atlantic. Since there are often a threat to the US mainland. But our long-distance have two hurricanes two hurricanes be concerned about in East Pacific. The first is named Iselle. The second behind it is named Julio.

Image courtesy of NOAA
Image courtesy of NOAA

Hurricane Iselle has a triggered the first hurricane warning, in many years for Hawaii. As of 11am HST, Iselle is about 625 miles east-southeast of Kilo, Hawaii, on the biggest island and is moving west-northwest at 16mph. Maximum sustained winds are 90mph. Often hurricanes coming from the west weaken due to cooler waters and high shear environment closer to Hawaii Islands. However, Iselle as actually done the opposite today as shear remains light over it. Some weakening down to a tropical still expected as Iselle get closer to Hawaii. But out of caution, the Central Pacific Hurricane Center has a hurricane warning, for the biggest island. Their forecast track takes the center right over the island.

11HST forecast from the Central Pacific Hurricane Center
11am HST forecast from the Central Pacific Hurricane Center

As of 2pm PDT, Julio is minimal hurricane with winds at 75mph. Current forecast Julio’s center moving north of Hawaii. Julio could be a threat in about 3-4 days. The track of Julio will dependent on how much of weakness in the ridge there will be north of Hawaiian Islands. A stronger ridge will force a track further south over Hawaiian Islands, as few tropical models show. But a many more are clustered with a track well north islands.

aep10_2014080618_track_earlyIt’s rare for hurricanes to hit Hawaii. The last hurricane to make a direct hit on Hawaiian islands was Iniki on September 11, 1992. The storm tracked south of tbe big island, where the ocean is warmer. Then it made a turn north and struck the western most island Kauai as a Category 4 hurricane with winds 135mph. It caused billions of dollars in damage and killed 6 people.

Bertha Strengthens As It Begins to Recurve

Miguel Pierre Tropics

Update: As of 11am EDT, the National Hurricane Center upgrades Bertha to catergory 1 hurricane with 80mph maximum winds. No other changes from below.

Tropical Storm Bertha became better organized and stronger overnight as shear decreased enough for more thunderstorms to wrap around it’s now closed surface center.  According to the National Hurricane Center,  maximum sustained winds have increased to 70mph and the central minimum pressure has fallen to 999mb. Bertha is now over very warm water and in an environment with less shear and dry air impeding further development. So it is likely to become a category 1 hurricane sometime today or tonight.

5amNHCtrackBertha has also turned north and will gradually turn to the northeast into the open Atlantic, ahead of upper-level trough over the Eastern US.  As the model consensus has been showing for days. The only impact from Bertha in tri-state area will likely be some high surf and rip currents along the shores as it makes it closest approach to our area sometime between Tuesday and Wednesday.  Then Bertha is expected to weaken and become a non-tropical system as it moves into the cooler waters of the North Atlantic, later this week.