Friday, August 22, 2014

Mostly Sunny with Light Winds and Moderate Seas

The CoCoView Resort Weather Forecast
This weather forecast is intended for CoCoView Resort guests and applies only to the south side of Roatan
CoCoView is at 16.4°N Latitude x 86.4°W Longitude
in the
   NW Caribbean Sea

             CoCoView Resort, www.cocoviewresort.com , 800-510-8164

How to use this page:
The title of each of the figures below is linked to the page where the information originates.
Since I write and post early in the day and generally do not update the page until the next morning; by clicking on the link, it allows you, the viewer, to get the latest information.
This is not only convenient but allows you to track weather events such as cold fronts and hurricanes from a single web page.
In addition, in the right column is a very useful widget. It is a trip planner...yesteryear's weather at a glance.This widget lets you check historic weather for your trip dates.

2014 Hurricane Outlook and Forecasts
The hurricane season in this hemisphere starts on June 01 and ends on November 30.
During that time frame, for your convenience, you will find a section below titled, "Tropical Weather Outlook".
It will contain the daily tropical storm outlook, forecast and storm track(s).

NOAA predicts near-normal or below-normal 2014 Atlantic hurricane season.
El Niño is expected to develop and suppress the number and intensity of tropical cyclones.
This year, the Saharan Air Layer (SAL) has been decreasing in size and density since May 21, 2014. This is important because it has been postulated, that the SAL, a cool, dry, layer of air which contains particles, may inhibit the formation of tropical storms and hurricanes. In addition, as it decreases in size and density, the probability of tropical storm formation may increase.

The outlook calls for a 50 percent chance of a below-normal season, a 40 percent chance of a near-normal season, and only a 10 percent chance of an above-normal season.  For the six-month hurricane season, which begins June 1, NOAA predicts a 70 percent likelihood of 8 to 13 named storms (winds of 39 mph or higher), of which 3 to 6 could become hurricanes (winds of 74 mph or higher), including 1 to 2 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher).
These numbers are near or below the seasonal averages of 12 named storms, six hurricanes and three major hurricanes, based on the average from 1981 to 2010. The Atlantic hurricane region includes the North Atlantic Ocean, Caribbean Sea and Gulf of Mexico.

Friday, August 22, 2017
Today, skies will be mostly sunny. Winds will be easterly in direction at 8 mph to 12 mph or less; increasing to 15 mph to 20 mph this afternoon and evening. Seas will be moderate to calm at 1 to 4 feet.
The air temperatures will range from the mid to high 70s (ºF) to the mid to high 80s (ºF) or 24ºC to 26ºC.
Ocean water temperatures are 82°F to 84°F or 24ºC to 25ºC. Visibility is 20 to 80 ft.




















Fig 19 - Recent changes in the Saharan Air Layer


The Tropical Weather Outlook
Shower activity associated with the small low pressure area, designated Invest 96L. It is moving over the Leeward Islands. It remains limited and disorganized. Interaction of the low with Puerto Rico and Hispaniola will likely inhibit significant development through tonight. However, environmental conditions are expected to be more conducive for development when the disturbance moves near or over the southeastern Bahamas on Saturday, and a tropical depression is likely to form over the weekend or by early next week. Regardless of tropical cyclone formation, gusty winds and heavy rainfall are expected across portions of the Leeward Islands, Puerto Rico, and the Virgin Islands today, and over Hispaniola and the southeastern Bahamas tonight and Saturday. Interests in those islands should monitor the progress of this disturbance. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate this system this afternoon.
  • Formation chance through 48 hours...high...60 percent.
  • Formation chance through 5 days...high...80 percent.
    Early this morning, Invest 96L was located from 26N63W to a low pressure near 18N62W moving W-NW at around 20 kt. Gale force winds just NE of this low are expected to diminish today. However...this system has the potential to develop into a tropical cyclone during the next day or two. The low is expected to pass near Puerto Rico today...near Hispaniola tonight into Saturday...and near the Turks and Caicos Islands late Saturday into Sunday.
    It currently poses no danger to the Bay Islands and North Coast of Honduras.

Atlantic Disturbance 96L Remains Disorganized - For Now…

By: Dr. Jeff Masters , 3:39 PM GMT on August 22, 2014

(By Steve Gregory - Substituting for Dr. Masters who is on Vacation.)

There has generally been little change overnight in disorganized tropical disturbance 96L, though the most recent upper level analysis and VIS imagery loops suggest the environment is becoming more conducive to cyclone formation within the next 12 hours, with the potential for further development to a strong Tropical Storm force cyclone later this weekend.

While the overall appearance of the disturbance remains poorly organized (with the appearance of at least 2 separate low level vortices during the last 36 hours} the most recent visible Satellite imagery loop suggests a primary surface circulation is located to the N/NE of Puerto Rico NEAR 19N/65.5W . However, at this point, limited surface/buoy/ship reports do not yet seem to clearly reflect this possible development.

While the overall satellite signature shows a rather elongated system, with convection widely dispersed, a burst of deep convection has developed over the last few hours near and across the NW and SE quadrants of the low level circulation center. San Juan Radar also depicts some 'banding' features developing to the SE of the newly forming center.

In addition, an upper level anticyclone has apparently formed over the last 3-6 hours near and just SW of the developing cyclone center. That said – wind shear still appears to be of moderate intensity near the center of the system (15Kt-20Kts) – though much lower shear values are clearly seen just SW of the center near the developing upper level anti-cyclone. Though these developments show a significant environmental improvement supporting cyclone development since yesterday – the nearby mountainous terrain of Hispaniola and Puerto Rico are likely to inhibit any rapid type of development during the next 12-36 hours.

The more reliable global model runs over the past 24 hours continue to call for a general track into the central Bahamas this weekend before turning northward Sunday as a break in the east-west orientated subtropical ridge to the north of the system develops further into a TROF over the next 48-72 hours, steering the system Northwestward and then Northward. Most every model (with 2 distinct exceptions) keep the cyclone away from the US mainland. (The CMC continues to track the system across south Florida – but this seems unlikely unless the system does NOT develop significantly for at least the next 72 hours – while the last OPNL ECMWF and GFDL model suite shows the storm first turning northward as the other major models do, but then suddenly turns the storm NW towards the Mid-Atlantic coast towards the middle of next week. However, the ECMWF Ensembles - which are typically much more reliable for developing systems - do NOT show this turn towards the coast.) Since the system has yet to become a well established cyclone, and upper level wind flow forecasts at these longer ranges during the warm season can be quite unreliable - all of these ‘outlier’ track forecasts remain highly suspect.

In addition, overall confidence in the intensity forecasts remains relatively low, though most of the more reliable, specialized hurricane models do call for a slow intensification to a CAT 1 storm after 72 hours as the storm begins to track northward away from the central Bahamas. Sea Surface Temps (SST’s) are very warm across the SW Atlantic near the Bahamas, with readings near or just over 29°C (~85°F), solidly supporting hurricane intensity, though the depth of the warm water remains relatively shallow (and a very slow moving storm would tend to upwell the somewhat cooler sub-surface water). All things considered, however, the model intensity forecasts subjectively look reasonable given the current stage of development.

A RECON is still planned for this afternoon, and I’ll have another update on this developing system late today.




Fig 1: The above VIS depicts an elongated, poorly organized disturbance with widely dispersed, though locally heavy, convection. Over the last few hours, a surface circulation appears to be developing NE of Puerto Rico with a strong convective burst noted to the N-NW of this circulation.



Fig 2: Wind Shear analysis (mid levels) shows moderate shear conditions in the 15-20Kt range in the vicinity of the primary low-mid level circulation. Much lower shear conditions are seen just south-southwest of the center. Since the shear analysis is automated, the values shown may not be very precise, though the very slow development is likely due in part to the less than optimal shear environment.




Fig 3: The most significant development since last night is the apparent development of an anti-cyclone at high levels, centered fairly close to the primary mid-level circulation center. Weak but distinct outflow channels are also apparent to the N-NW and South of the developing cyclone.



Fig 4: The lower level steering winds (used for a shallow / developing cyclones) clearly shows the east-west orientated sub-tropical ridge from the central Atlantic westward to the Gulf coast region, along with a developing weakness between the two separate High pressure centers. If the system does NOT develop, it will likely tend to continue W-NW towards Florida. However, any significant development, along with the global model forecasts for a break in the ridge line near the central Bahamas, should lead to the cyclone turning northward late this weekend as it tracks around the western periphery of the central Atlantic High pressure center.



Fig 5: Early cycle model runs are in very good agreement on the track of the cyclone ultimately turning away from the US mainland, though there is that 'sudden turn towards the coast' by a couple models that cannot be totally discounted.



Fig 6: Intensity forecasts have been fairly consistent over the past couple days, with slow intensification expected during the next 24-72 hrs, with an increase in intensity to CAT 1 Hurricane force during the 3-5 day period.


Steve



 Fig 21a - Graphical 5 Day Tropical Weather Outlook

Fig 23 - 48 Hour Tropical Storm Probability



 Fig 26 - Storm Statistics  96L
low tide 1:05 am LT                Moon Rise – 3:07 am LT
high tide 6:52 am LT               Moon Set –4:14 pm LT
low tide 1:00 pm LT                Sunrise – 5:33 am LT
high tide 7:22 pm LT               Sunset – 6:08 pm LT


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