Hurricane Maria Intensifies to a Major Hurricane - Update: Now Category 4

Hurricane Maria continued to intensify overnight and as of the 11 am advisory is a category 3 major hurricane with sustained winds of 105 kt (120 mph) and a minimum central pressure of 959 mb. On it’s present course the storm will pass near or over the islands of Martinique and Dominica this evening. There is considerable prospect that Maria will intensify further before a likely landfall on Dominica, likely as an upper-end category 3.

The well-defined eye of #Maria is approaching Martinique and Dominica. Weather conditions will go rapidly downhill later today- be careful! pic.twitter.com/rbLTdUhkWZ

Hurricane #Maria spinning east of #Martinique - #GOES16 1-min VIS pic.twitter.com/myy4YYUBDY

An Air Force reconnaissance plane has been flying the storm this morning and has found ample evidence supporting the classification as a major.

WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY:

A Hurricane Warning is now in effect for the U. S. Virgin Islands.

The Meteorological Service of Antigua has issued a Hurricane Warning for the British Virgin Islands, and a Tropical Storm Warning for Anguilla.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for... * Guadeloupe * Dominica * St. Kitts, Nevis, and Montserrat * Martinique * St. Lucia * U.S. Virgin Islands * British Virgin Islands

A Tropical Storm Warning is in effect for... * Antigua and Barbuda * Saba and St. Eustatius * St. Maarten * Anguilla

A Hurricane Watch is in effect for... * Puerto Rico, Vieques, and Culebra * Saba and St. Eustatius * St. Maarten * St. Martin and St. Barthelemy * Anguilla

A Tropical Storm Watch is in effect for... * Barbados * St. Vincent and the Grenadines

The NHC discussion notes:

Reports from an Air Force Reserve Hurricane Hunter aircraft indicate that Maria is undergoing rapid intensification.  The aircraft reported 700-mb flight-level winds of 115 kt in the northeastern eyewall, along with reliable-looking surface wind estimates from the Stepped Frequency Microwave radiometer as high as 104 kt.  In addition, the estimated central pressure inside the 10 n mi wide eye has fallen to 959 mb.  The initial intensity is increased to 100 kt, making Maria a major category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale.  The small eye is also apparent in radar data from Martinique. ... Atmospheric and oceanic conditions appear favorable for additional rapid strengthening for the next 24 h and possibly longer. This is reflected in the intensity forecast, which now calls for Maria to become a category 4 hurricane in 12 h and reach a possibly conservative peak intensity of 130 kt in about 36 h.  From 72-120 h, land interaction and less favorable upper-level winds are expected to cause some weakening.  On top of these general trends, there is also the possibility that eyewall replacement cycles could occur that would affect the intensity.  However, Maria is likely to maintain category 3 to 4 intensity through the forecast period.

(emphasis mine)

(either that 100 kt initial intensity is a typo or they revised it up to 105, because both the public advisory and the forecast advisory have the higher number)

There is no significant change in the model guidance over the next three days. Maria is expected to impact the islands of Martinique and Dominica, with significant effects felt in the islands both a little to the south and especially a little to the north. After that, Maria is expected to continue on a west-northwest course in the direction of the US Virgin Islands and Puerto Rico, intensifying significantly as it does. The islands of Guadeloupe, Montserrat and St. Kitts & Nevis will likely avoid a direct impact but will see at least significant tropical storm conditions as well as very heavy rains.

The Virgin Islands (especially British but also US) suffered a significant impact from Hurricane Irma and are just beginning recovery efforts. Neither they nor Puerto Rico are even remotely prepared to deal with a direct impact of a strong category 4 hurricane. Unfortunately that seems close to certain at this point and a category 5 impact is not out of the question. This is an extreme emergency situation for these islands.

Beyond Puerto Rico, the eastern portion of the Dominican Republic is likely to see heavy rains and tropical storm conditions at least. If Maria tracks a little bit left, the DR could see a direct impact. Even if the DR avoids that direct impact this is likely to be a serious flooding event.

The Turks and Caicos and the southeastern Bahamas also need to be preparing for a possible impact of a major hurricane.

Here are the ensembles from the overnight run f the ECMWF:

and this morning’s run of the GFS:

showing good agreement on Maria’s track for the first four days. Beyond that, the models appear to be converging on a solution which keeps a weak remnant of Hurricane Jose offshore from the northeast US coast, creating a weakness in the ridge that allows Maria to pass near but most likely offshore from the US coast. It will be a few days yet before we can feel confident in this solution.

I will be updating this diary during the day as new information comes in. Please keep the people of the islands in your thoughts as they face yet another devastating blow.