After racing across the eastern Caribbean as an strong tropical wave, Invest 97L has finally been dubbed Tropical Storm Earl
. Late Tuesday morning, an Air Force hurricane-hunter mission found that Earl had developed a closed circulation center with a minimum central pressure of 1001 millibars. Flight-level winds reached 52 knots (57 mph)
just after noon EDT Tuesday. In an special update issued at noon EDT Tuesday
, the National Hurricane Center placed the center of newly christened Earl about 535 miles east of Belize City, Belize, with top sustained surface winds of 45 mph. Carrying a large though somewhat disorganized assortment of showers and thunderstorms (convection), Earl was moving westward at 22 mph, a pace expected to slow over the next 24-48 hours as Earl approaches Belize and the Yucatan Peninsula. Even before Earl’s designation as a tropical storm, high winds in the Dominican Republic brought power lines down and sparked a fire aboard a bus, killing 6 and injuring 12 people, according to weather.com
. Three others were killed after a tour boat overturned, although that incident had not yet been confirmed to be weather-related. The Meteorological Service of Jamaica issued a tropical storm warning for 97L
on Monday night, and on Tuesday the Cayman Islands National Weather Service
was cautioning small craft to exercise caution in open waters. Surface winds at Kingston, Jamaica, peaked at 29 mph
early Tuesday morning, with only light rain observed, although showers and squalls have affected other parts of Jamaica.Figure 1.
Flight-level wind data gathered by an Air Force hurricane-hunter flight through 1604Z (12:04 pm EDT) Tuesday, August 2, 2016. The light westerly winds to the west of Earl’s center (the dot with the “1002”-mb label) showed that a closed circulation was evident at flight level. Image credit: tropicaltidbits.com
Infrared satellite image of Tropical Storm Earl at 1615Z (12:15 pm EDT) Tuesday, August 2, 2016. Image credit: NOAA/NESDIS
.What took Earl so long?
During its time as 97L, Earl puzzled tropical weather watchers and forecasters with its dramatic appearance on satellite coupled with its inability to qualify as a tropical depression or tropical storm. In part, this is because Earl has been more organized aloft than at the surface. During the classic nocturnal peaks of convection (shower and thunderstorm activity) on both Sunday and Monday night, 97L developed a large mass of convection near its center, with fairly symmetric upper-level outflow evident in all directions on satellite imagery. Because 97L’s rapid westward motion of 25-30 mph was roughly in line with upper-level winds, there was little vertical wind shear affecting the system, thus helping the convection to remain symmetric and well structured. The crucial ingredient missing at the surface was a closed center of circulation around which surface winds were rotating. In order to qualify as a tropical depression or tropical storm, a closed surface wind circulation is required by definitions employed by NHC and the World Meteorological Organization for the North Atlantic and East Pacific. Surface winds measured on Monday by the Advanced Scatterometer (ASCAT) aboard Europe’s MetOp-B satellite showed easterly winds of 30-40 mph on the north side of 97L, but southerly rather than westerly winds on its south side. An Air Force reconnaissance flight into 97L was aborted due to mechanical difficulties
on Monday afternoon, so Tuesday morning’s flight was the first to gather data from within the storm. Figure 3.
WU depiction of the NHC track forecast for Tropical Storm Earl issued at noon EDT Tuesday, August 2, 2016.The outlook for 97L
Although Earl kept forecasters guessing as to exactly when it would become a tropical storm, forecast models have come into increasing solidarity on Earl’s prognosis. A sprawling area of high pressure to the north of Earl will keep the storm moving on a general westerly path. Even though it will slow down a bit over the next day or two, Earl still has less than two days to gather strength before it makes landfall late Wednesday, most likely in Belize but possibly on the far southeast Mexican coast of the Yucatan peninsula. The official NHC outlook keeps Earl just below hurricane strength at landfall late Wednesday night. Wind shear is predicted by the SHIPS model to remain at a light to moderate 10 - 20 mph, although parts of the circulation are being affected by stronger shear to the north associated with a slow-moving upper-level trough over the northwest Atlantic. We will have to keep a close eye on Earl tonight and Wednesday, as sea-surface temperatures are more than 1°C above average
over the northwestern Caribbean, and Earl’s path will put it on the south edge of an area of of extremely high oceanic heat content that covers most of the northwest Caribbean. These waters would support rapid intensification if other conditions were favorable, although Earl may not be well enough organized to take full advantage of this oceanic rocket fuel.
The 00Z Tuesday ensemble runs of the ECMWF model were unanimous in keeping Earl as a weak tropical storm, while most members of the 06Z Tuesday GFS ensemble brought Earl up to strong tropical storm strength. The 12Z Tuesday run of the SHIPS statistical model
gives Earl a 21% chance of a 24-hour increase of 25 knots in sustained winds, which would bring Earl to the threshold of hurricane status. Although the prospect is unlikely, I wouldn’t be shocked to see Earl become a minimal hurricane just before landfall, as predicted by the 06Z Tuesday run of the HWRF model. We’re very lucky that Earl is moving across the Caribbean so quickly, or else it could have become a much more formidable storm. If Earl remains far enough north on its trek across the Yucatan, it may have a brief window to reorganize across the southern Bay of Campeche, where the short-lived Tropical Storm Danielle
formed in late June. It’s worth noting that Earl will be the fifth of all five named systems in the Atlantic this year to make landfall somewhere.Elsewhere in the tropics
The short life of Tropical Storm Howard
may have already hit its high point, with Howard’s sustained winds holding at 60 mph at 9:00 am EDT Tuesday
. Located about 1250 miles west of the southern tip of Baja California, Howard was chugging west-northwest at 15 mph. Models are consistent in keeping Howard on this track well away from any land areas, with a gradual arc toward the west by late in the week. Although Howard will be moving over waters cooler than 26°C by Wednesday, wind shear will remain light to moderate for several days, so Howard will likely take a while to spin down, potentially remaining a tropical storm throughout the week. By this weekend, Howard’s path is expected to arc gradually leftward toward the northern Hawaiian Islands. It is unlikely that Howard would strike any of the islands as a tropical storm, although Howard or its remnants could bring some squally weather and high surf by Saturday or Sunday. Southeast of Howard, the next in the conga line of East Pacific storms may soon develop from Invest 92E
, which was classified on Monday. As with its predecessors, 92E will be moving away from the Mexican coast on a straightforward west-northwest track. Models suggest that 92E is likely to become Tropical Storm Ivette by midweek—which would make it the ninth named storm for the East Pacific in just five weeks!—but there is little sign of major intensification beyond that point, as 92E will be moving across cooler waters. Figure 4.
WU depiction of the NHC track forecast for Tropical Storm Howard issued at 11:00 am EDT Tuesday, August 2, 2016.Figure 5.
A MODIS image of Typhoon Nida taken from aboard NASA’s Aqua satellite as Nida it approached the China coast on August 1, 2016. Image credit: NASA Earth Observatory
.Nida reaches Hong Kong
The southern coast of China came away relatively unscathed from the arrival of Typhoon Nida
, which swept across the northernmost part of the Hong Kong area at Category 1 strength around 1800Z (2:00 pm EDT) Monday, August 1, or just after midnight Tuesday local time, moving on to pass directly over the sprawling inland city of Ghaungzhou. There was major disruption across the region on Tuesday, including hundreds of flight cancellations and delays, but little damage and no injuries have been reported
. Wind gusts peaked at around 64 mph at Hong Kong’s Chek Lap Kok airport
. Nida was continuing to dump very heavy rains in coastal provinces to the west of Hong Kong as it pushed inland late Tuesday local time.”My friends”: Remembering the irreverent, irreplaceable Dave Schwartz
The world of weathercasting lost one of its most colorful and beloved figures on Saturday with the passing of the Weather Channel’s Dave Schwartz on Saturday (see this Weather Channel tribute
). Dave was a fixture on TWC’s Weather Underground series (#WUTV) from the show’s inception in 2015, with his blackboard-based “WOW Factor” analyses and his quirky yet accessible style helping to solidify the show's role as a home for unapologetic, full-on weather geekery. Dave was also forthright about his longtime struggle with cancer. Early this year, on World Cancer Day, Dave told viewers about his extended battle (the full story can be found at this Weather Channel blog post
). Back in the mid-2000s, Dave learned he had stage 2 pancreatic cancer. The five-year survival rate for all forms of pancreatic cancer is only 6%, yet Dave survived not only the initial cancer but a recurrence a year later. After almost ten years of remission, Dave was diagnosed last year with stomach cancer, but he remained on the air well into 2016. “In a sense, having cancer and the impact it has on my life has really enriched my life tremendously through strengthening my relationships with people,” he said.
Dave had been part of the Weather Channel for most of its 34-year existence, starting in 1985 as a newsroom assistant and becoming an on-camera meteorologist in 1992. A native of Philadelphia and a weather geek from childhood, Dave earned his bachelor’s degree in psychology from Temple University, later earning a certificate in meteorology studies from Mississippi State University. I believe this hybrid background helped shape Dave’s unique, people-centered approach to weathercasting, which was exemplified in his love of language, his eye for captivating weather tidbits, and his perennial reference to viewers as “my friends.” I greatly enjoyed Dave’s weathercasts from the start and was fortunate enough to meet him on a TWC visit years ago, though I wish I’d had the chance to know him better. WUTV’s Mike Bettes and Alex Wilson paid tribute to Dave on Monday (see embedded video below), including a collection of tributes from coworkers placed on his beloved chalkboard. “His chalkboard was his weather canvas that wowed us every day,” noted Bettes. From Wilson: “He taught me more than I could have learned from years of school, and I’ll never forget his zest for life.”
Bob HensonVideo 1.
Mike Bettes and Alex Wilson pay tribute to Dave Schwartz on the Weather Underground series on Monday, August 1, 2016.