As of the 9:00 PM advisory from the National Hurricane Center, Maria was located 145 miles southeast of San Juan Puerto Rico. The very dangerous storm was tracking toward the west-northwest at 10 miles per hour. Packing maximum sustained winds of 175 miles per hour and a minimum central pressure of 909 mb, the storm is now stronger than it was just prior to devastating Dominica yesterday evening and features a lower central pressure than Irma at maximum intensity. Furthermore, the storm is now one of the ten strongest ever to form in the Atlantic by measure of central pressure alone.

Along its present and projected path, the storm will reach the vicinity of St. Croix in the Virgin Islands a bit after midnight. Following a close encounter with St. Croix, the storm should approach Vieques and the Puerto Rican southeast coast by early morning on September 20th. Hurricane force winds should arrive about three to four hours prior to passage of the storm center. Tropical storm force winds are already affecting parts of the Virgin Islands and should begin to impact Puerto Rico soon.

In addition to catastrophic winds, the National Hurricane Center expects 7-11 foot storm surges in the Virgin Islands and 6-9 foot storm surges in Puerto Rico topped by powerful breaking waves. Rainfall totals are likewise expected to be quite extreme — totalling 10-20 inches in the Virgin Islands and 12-25 inches in Puerto Rico.

Some of the far outer bands of Maria are presently lashing Puerto Rico with rains and gusty winds. Meanwhile, St Croix in the Virgin Islands recently reported a wind gust of 72 mph.

Maria is passing over very warm sea surfaces in the range of 29 to 30 degrees Celsius. These abnormally warm ocean waters appear to be facilitating further intensification just prior to potential landfalls.

6:29pm: Recon measuring an unbelievable 909-910mb pressure w/ 175mph estimated surface winds in #Maria's northern eyewall. When will it stop pic.twitter.com/Kjy8UAln7t — Levi Cowan (@TropicalTidbits) September 19, 2017

Maria is now a somewhat larger storm than it was when it approached Dominica. Hurricane force winds now extend upwards of 35 miles from the storm center and tropical storm force winds up to 140 miles. The storm appears to still be strengthening with the most recent report of 909 mb pressures near the storm center over the past hour 11 mb lower than a reading taken late Tuesday afternoon and 3-4 mb lower than a reading taken just one hour ago. Maximum sustained winds from this more recent pass were recorded at 175 mph. Maria is now stronger than Irma at peak intensity by measure of central pressure. A yet more powerful storm capable of producing more damage along a wider swath than during last night’s encounter with Dominica.

To say this is a dangerous situation is an understatement. Those in the path of this storm should heed any and all statements from emergency officials and do everything possible to seek shelter or flee the path of this terrible storm.

Conditions in Context

Climate change related factors like warming ocean surfaces, more intense Equatorial thunderstorms, and increasing atmospheric water vapor content have contributed to higher storm intensities during the present hurricane season. Natural factors, like La Nina-like conditions in the Equatorial Pacific, have also contributed. But we should be clear that the primary limiters to peak hurricane intensity — ocean surface temperature and atmospheric water vapor content — are now higher than they were in the past. So the storms of today can hit higher bars than before.

(Accumulated Cyclone Energy or ACE for 2017 so far is well above average. There are approximately 8 weeks left in this year’s hurricane season. Image source: Colorado State University.)

Overall, 2017 has been a well above average year for storms. One in which a number of records have already been broken.

One measure of tropical cyclone intensity — accumulated cyclone energy or ACE — has hit considerably higher than normal marks during 2017. So far, 2017 has outpaced all years since 2010 and appears to be on track for one of the highest ACE years on record. The record highest ACE for any given year was 2005 at approximately 250.

RELATED STATEMENTS AND INFORMATION:

(UPDATED– UPDATES TO FOLLOW)

Links:

The National Hurricane Center

Colorado State University

Hat tip to Eleggua

Hat tip to Bostonblorp