Update on Hurricane Maria (2:30 pm EDT). High winds and flooding rains impacting Puerto Rico.

Hurricane Maria is beginning to emerge from the island of Puerto Rico after the center made landfall 8 1/2 hrs ago as a Category 4 storm with max winds of 155 mph (Cat 5 is 156+ so catastrophic wind speeds occurred). 

The hurricane is now a Category 3 storm with 115 mph sustained winds and gusts over 130 mph near the center. Damaging winds and torrential flooding rains will continue for the rest of the afternoon as the system continues to push out into open ocean water.

Most computer models indicate the system should remain offshore the United States as it moves north in a weakness in the upper level higher pressure field caused by the presence of Tropical Storm Jose offshore the Mid-Atlantic and southern New England.

The crucial timing to be rid of Maria forever will be the approach of a significant upper level trough of low pressure from the Midwest midweek next week to “kick” the dying hurricane out to sea. Most models show this connection keeping the system offshore being, however there is higher variability in the track after Monday which could bring the system closer to shore than expected. Currently, I feel direct impacts…the tropical storm force wind field and significant rain bands…will likely (66%+ probability) stay offshore. But potential variability makes the situation worth watching closely. 

Regardless, high surf and rip currents (currents which pull water offshore and make swimming dangerous) are likely by early next week. The system will also be weaker offshore the East Coast thanks to less intense sea surface temperatures and increasing vertical wind shear from mid-latitude winds.

In the meantime, direct impacts from a Cat 3-4 storm are likely for north coast of the Dominican Republic, the Turks and Caicos Islands and the southern Bahamas. Hurricane warnings are in effect for all these areas. 

–Meteorologist Nick Humphrey


Update on Hurricane Maria (6:30 am EDT)

#Maria is making landfall in eastern Puerto Rico as a Category 4 Hurricane with maximum sustained winds of 155 mph. Gusts of 160+ are likely in progress over northeast coast of PR. Catastrophic weather conditions will continue to spread across the island over the next couple of hours. 

Terrible situation for the 3.5 million people hunkering down this morning. 

PR Radar failed just before 6 am EDT. More inbound winds of 155 mph or higher as eyewall moved over radar site (which is in elevated terrain and winds likely much stronger).

Update on Hurricane Maria (1:30 am EDT)

The hurricane…which is currently undergoing an eyewall replacement cycle with a double eyewall structure…is moving just to the southwest of St. Croix. Wind gusts up to 140 mph have been reported on the western edge of the island just miles from the inner eyewall. The outer eyewall brought initial gusts over 100 mph to the island as it came ashore in the last hour and a half.

The center is still expected to make landfall as a Category 5 storm after day break in southeastern Puerto Rico.

–Meteorologist Nick Humphrey

Hurricane Maria continues to intensify this evening as it makes approach to USVI and Puerto Rico

Hurricane Maria…after devastating the island nation of Dominica with maximum sustained winds of 165 mph and gusts over 190 mph…is now threatening the highly populated US territory of Puerto Rico and also the US Virgin Islands as a Category 5 hurricane. Maximum sustained winds are near 175 mph at 8 pm EDT and the hurricane continues to intensify. It is now the 9th most intense hurricane on record by minimum central pressure (906 millibars as extrapolated by the USAF Reserve Hurricane Hunters; more than 100 mb lower than Earth’s average sea level pressure). For comparison, the most intense hurricane on record in the North Atlantic was 2005 Hurricane Wilma (882 mb) and 2005 Hurricane Katrina by comparison had a minimum central Pressure of 902 mb at its peak with winds of 175 mph (ranked 7th by pressure). There are signs the hurricane is continuing to intensify. The next hurricane hunter plane will arrive in the storm by 10:30 pm EDT.

Mid-level water vapor imagery by the GOES 16 satellite (non-operational, in testing). It shows the very powerful circulation of Maria and the very dry/warm eye in the center (image at 8:27 pm EDT).

As of now, there is absolutely NOTHING to stop the power of the storm, except internal, inner core processes (like an eyewall replacement cycle). The waters under Maria are 1-1.5 degrees C (~2-3 degrees F) above normal and the oceanic heat content (includes warmth with depth) and resulting tropical cyclone heat potential is MUCH above normal along the track.

5-day Track forecast for Maria (NHC).

The eye will pass near or over the island of Saint Croix late tonight and make landfall in Eastern Puerto Rico tomorrow morning. Both landfalls are expected at Category 5 intensity with gusts over 185 mph in the inner core (particularly northern eyewall). In addition to the violent winds, rainfall of 12-18+ inches are possible over the USVI and Puerto Rico, along with landslides in the mountainous terrain, where winds may also be even more violent than near sea-level.

Needless to say, this is a truly horrific situation evolving for a territory of 3.5 million people; and a territory still recovering from much weaker hurricane impacts from Irma two weeks ago. USVI such significant damage from Irma as well.

I will an update on Maria later this evening as new data comes in.

–Meteorologist Nick Humphrey

Catastrophic Hurricane Irma heading for Leeward Islands. Florida must get ready.

Category 5 Hurricane Irma bearing down on the Leeward Islands at 8:45 am CDT Tuesday.

If you’re in South Florida or the Florida Keys…you need to know what you’ll to once watches and warnings are issued BEFORE they are issued. I do have enough confidence in the path of Hurricane Irma to state that Florida is in a very serious situation based on forecast data and so folks need to 1) track the forecast 2) know your plan, especially if you live in coastal evacuation zones 3) have emergency supplies ready. This storm already has the potential to be devastating for many people all week as it buzzsaws its way through the northern Leeward Islands, close approach to US and British Virgin Islands, then the US territory of Puerto Rico with 3.5 million people, the Dominican Republic, then portions of the Bahamas, before a close passage of the coast of Cuba. And it could do this as a large Category 4-5 hurricane. 
Most likely time of arrival of tropical storm force winds overlay 7 am CDT probability of those winds during 5 day forecast period. Note South Florida is most likely to see winds arrive by Saturday morning and they could arrive overnight Fri-Sat, with the eye not expected near Florida until Sat night-Sun morning.

Get ready, be ready to act if/when watches/warnings are issued and keep track of the latest forecast. Also, hope the best for our friends facing Irma right now.

I’ll updates on Irma throughout the week and you can follow me on Facebook and Twitter.

EDIT AT 10:20 am CDT: Winds in Hurricane Irma increased to 180 mph, making it the most powerful hurricane (by wind) ever observed in the North Atlantic outside the Gulf of Mexico and Caribbean Sea.

–Meteorologist Nick Humphrey

Hurricane Irma threatening the Lesser Antilles; landfall risk increasing for US late week

PHurricane warnings have been issued for the northern islands of the Lesser Antilles as Hurricane Irma – as of this post, a Category 3 Hurricane with maximum sustained winds of 115 mph – approaches after days of crossing the tropical Atlantic from its birthplace over West Africa.

Enhanced infrared satellite image of Irma.

The hurricane is expected to intensify into at least a Category 4 hurricane as it approaches the Lesser Antilles Tuesday. This will be as a result of a combination of reduced vertical wind shear and gradually warming sea surface temperatures along the track. Areas near center will face destructive winds, highest storm surge/surf, and torrential rain. 

In addition to the Lesser Antilles, Puerto Rico, the Dominican Republic, and the Bahamas will need to be ready to make preparations if and when watches and warnings are issued. If trends in the forecast continue, they will likely be required in the next 48-72 hrs.

As for the United States…the risk of landfall by Irma is increasing as models indicate the possibility of either landfall somewhere along the East Coast (particularly the Southeast to Mid-Atlantic) or an offshore recurvature ultimately heading out to sea. Obvious, the implications for damage potential are dramatically different for either grouping of scenarios. Stay up to update on the latest forecast. We should continue to know more over the next few days.

Expected onset of tropical storm force winds and the probability of tropical storm force winds as of the advisory time.

Probability of hurricane force winds.

–Meteorologist Nick Humphrey 

The North Atlantic Tropics Looking to become Active Again This Weekend or Next Week

It’s August and with that it’s time for the North Atlantic to show its tropical cyclone “muscle”. Tropical waves become more numerous as mesoscale convective systems form over the tropics of West Africa and race off into the open Atlantic; their mid-level “vorticity” or spin the seed for possible further development. The National Hurricane Center in Miami has pegged one Thursday with an 80% chance of development between now and Tuesday (40% chance between now and Saturday).

ir2 (1)
Shortwave infrared image (sometimes known as “nighttime visible”) taken at 8 pm EDT Thursday. This shows a cloud mass moving off West Africa associated with a new tropical wave south of the Cape Verde Islands. (NOAA)

Mid-range models suggest the system will develop possibly into a depression or tropical storm, moving generally westward toward the Lesser Antilles heading toward Tuesday. Much more on what will happen will depend on the system’s development. Mid-level dry air brought in from the Sahara Desert will be an issue for this system as it approaches the Lesser Antilles if it moves north of 15N. As far as upper-level winds, forecast shows a modestly favorable environment for development, but details will wait until down the road. Water temperatures in this part of the Atlantic – known as the Main Development Region (MDR) – are running up to 1.5 C (~3 F) above average with abundant warm sea surface temperatures above 26 C (79 F) west of 35 W.

Current Sea Surface Temperatures over the tropical Atlantic Ocean. The orange-red and red shades indicate temps at and above 26 degrees C. (Wunderground.com)

Because of the strong semi-permanent “Bermuda High” expected to dominate the Central and Western Atlantic next week, this system will need to be watched by interests in the Western Atlantic Basin for potential impacts in case it does not curve northeastward out to sea because of the subtropical high pressure system to its north (assuming it develops).

Also of interest is a system in the Eastern Caribbean Sea. It is in a more hostile environment (shear and dry air main problems) and only has a 40% chance of development over the next 5 days.

Shortwave IR image at 8:45 pm EDT showing generally disorganized thunderstorm activity associated with a tropical wave in the Eastern Caribbean. (NOAA)

The Atlantic has been running about a month ahead of schedule on named storms, but has been dead quiet on hurricanes. The 1966-2009 average for the first hurricane in the basin is coming up (August 10th), but given recent years of activity, the Accumulated Cyclone Energy (ACE) thru Aug. 2nd is running at its lowest level in the basin since 2009. But still 90% of the ACE on average occurs from here on out, so much can still happen, especially given the lack of one otherwise major hindering presence in El-Nino.

I’ll keep track of these disturbances in the coming days and have more for you if they develop into organized systems. Stay tuned!