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Tropical Storm Guillermo (Eastern Pacific Ocean)

Satellite Data Shows Wind Shear Socking Guillermo Near Hawaii 

Tropical Depression Guillermo on Aug. 7, 2015, at 8 a.m. EDT
NOAA’s GOES-West satellite captured an infrared image of Tropical Depression Guillermo on Aug. 7, 2015, at 8 a.m. EDT, showing the storm was elongated from southwest to northeast.
Credits: NASA/NOAA GOES Project

Satellite data revealed that Tropical Depression Guillermo doesn’t have much punch left in it as a result of strong, persistent vertical wind shear that continues to pound away at the storm’s structure.

On Friday, August 7, the former tropical storm weakened to a tropical depression and was located just north of the main Hawaiian Islands.

NOAA’s GOES-West satellite captured an infrared image of the depression’s clouds pre-dawn on August 7. At 1200 UTC (8 a.m. EDT/2 a.m. HST), the GOES image showed Guillermo’s elongated clouds stretching from southwest to northeast. The image was created by NASA/NOAA’s GOES Project at NASA’s Goddard Space Flight Center, Greenbelt, Maryland.

The Central Pacific Hurricane Center (CPHC) reported that there was one lone thunderstorm with a cloud top near 32 thousand feet, located about 90 miles northeast of the center. The hostile environmental vertical wind shear continues to inhibit any more thunderstorms from developing especially near the center.

Although there are no watches or warnings in effect, ocean swells post the greatest hazard. Swells associated with Guillermo will continue to produce large…life threatening surf along east facing shores of most Hawaiian Islands.

On August 7, 2015 at 5 a.m. EDT//0900 UTC) the center of tropical depression Guillermo was located near latitude 22.2 north and longitude 157.1 West. That’s about 80 miles (130 km) northeast of Honolulu and about 150 miles (240 km) east of Lihue, Hawaii. The depression is moving toward the west near 14 mph (22 kph). Maximum sustained winds are near 35 mph (55 kph). The estimated minimum central pressure is 1008 millibars.

NOAA forecaster Houston noted “Guillermo has a near zero chance of redevelopment as a flattening upper level trough (elongated area of low pressure) to the north will maintain strong vertical wind shear and dry air aloft in the vicinity of the depression and its remnants during the next few days.”

Guillermo is expected to gradually weaken…and is forecast to become a remnant low later today and dissipate on Saturday, August 8.

Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Aug. 6, 2015 – NASA Sees Tropical Storm Guillermo’s Big Stretch

AIRS image of Guillermo
Strongest thunderstorms and coldest cloud tops near -63F/-53C (purple) in Guillermo were east of the center on Aug.5 at 2253 UTC (7:53 p.m. EDT) in this infrared data from NASA’s Aqua satellite AIRS instrument.
Credits: NASA JPL, Ed Olsen

When you look at Tropical Storm Guillermo on infrared NASA satellite imagery it looks stretched out with a “tail” of clouds extending to the northeast. That’s because westerly wind shear continues to batter the storm and weaken it.

Strongest thunderstorms and coldest cloud tops near -63F/-53C in Guillermo were pushed east of the center on Aug.5 at 2253 UTC (7:53 p.m. EDT). Infrared data from the Atmospheric Infrared Sounder or AIRS instrument that flies aboard NASA’s Aqua satellite captured data that showed the effect of the strong westerly wind shear.  

GOES-West image of Guillermo
This GOES-West infrared image of Guillermo from August 6 at 1200 UTC (8 a.m. EDT) westerly wind shear continued pushing clouds and showers northeast of the center.
Credits: NASA/NOAA GOES Project

The next day, NOAA’s GOES-West satellite provided another infrared look at Guillermo that confirmed the strong vertical wind shear was still happening. In an image taken August 6 at 1200 UTC (8 a.m. EDT), the storm looked almost wedge-shaped.

Because of the asymmetric shape of Guillermo, the tropical storm watch has been discontinued for the islands. However, it remains in effect for the coastal waters northeast of the main Hawaiian Islands from Maui to Kauai.

NOAA’s Central Pacific Hurricane Center (CPHC) noted that the swells associated with tropical storm Guillermo will continue to produce large, life threatening surf along east facing shores of the main Hawaiian Islands today, August 6, 2015.

At 0900 UTC (5 a.m. EDT) on August 6, Guillermo’s maximum sustained winds are near 50 mph (85 kph), however, steady weakening is expected during the next couple of days as wind shear is expected to continue and the storm is encountering dry air,

The center of storm was located near latitude 21.8 north and longitude 153.2 west. That’s about 190 miles (305 km) northeast of Hilo, Hawaii and about 305 miles (490 km) east of Honolulu. Guillermo is moving toward the west-northwest near 10 mph (17 kph) and is expected to continue in that general direction through August 7, however, the CPHC cautioned that any deviation of the track to the left could bring tropical storm force conditions into portions of the windward coastal waters of the islands from Maui to Kauai.

The CPHC forecast noted that Guillermo may become a tropical depression Thursday night or Friday, August 7.

Rob Gutro
NASA’s Goddard Space Flight Center

Aug. 05, 2015 – NASA Looks at Tropical Storm Guillermo Closing in on Hawaii

MODIS image of Guillermo
On August 4 at 20:50 UTC 4:50 p.m. EDT NASA’s Terra satellite captured this visible image of Tropical Storm Guillermo off Hawaii.
Credits: NASA Goddard MODIS Rapid Response Team

NASA’s Terra satellite and RapidScat provided forecasters with information about Tropical Storm Guillermo, revealing that the strongest winds were on the northern and eastern sides.

A tropical storm watch is in effect for Hawaii county, and Maui county, including the islands of Maui, Molokai, Lanai and Kahoolawe. Those areas can expect rainfall totals of 1 to 3 inches, locally up 7 inches in higher terrain. In addition, east facing shores of the Hawaiian Islands will see large surf through the rest of the week.

RapidScat image of Guillermo
On August 4, the RapidScat instrument observed Tropical Storm Guillermo’s strongest winds on the northern and eastern sides of the storm (red) while winds were much weaker (blue) on the other sides.
Credits: NASA JPL, Doug Tyler

From its perch on the International Space Station, the RapidScat instrument gathered surface wind data on the Central Pacific Ocean’s Tropical Storm Guillermo on August 4 at 9 a.m. EDT as it neared Hawaii. RapidScat data showed the strongest winds on the northern and eastern sides, while winds on the western side of the storm were much weaker. Strongest sustained winds were between 24 and 27 meters per second (53.6 mph/ 86.4 kph and 60.4/97.2 kph). Tropical storm force winds extend outward up to 185 miles (295 km) from the center, mainly to the north of the center. 

On August 4 at 20:50 UTC 4:50 p.m. EDT NASA’s Terra satellite captured a visible image of Tropical Storm Guillermo. In the image thunderstorms surround the center of the circulation but area also pushed to the northeast of the center from wind shear. RapidScat data confirmed that the northeastern quadrant is where the strongest winds were occurring.

At 11 a.m. EDT (5 a.m. HST/1500 UTC) on August 5, the center of tropical storm Guillermo was located near latitude 20.5 North and longitude 151.2 West. It was about 260 miles (415 km) east-northeast of Hilo, Hawaii. Maximum sustained winds are near 60 mph (95 kph) but the National Hurricane Center expects steady weakening over the next couple of days.

Guillermo is moving toward the west-northwest near 9 mph (15 kph) and is expected to continue in that direction. The center of Guillermo is expected to pass about 160 miles north-northeast of the big island late tonight, August 5, and 90 miles north-northeast of Maui on Thursday, August 6. The estimated minimum central pressure is 999 millibars.

NOAA’s Central Pacific Hurricane Center forecast calls for Guillermo to move northwest over the next several days, moving almost parallel the Hawaiian Islands.

The storm is moving into an area of increasing vertical wind shear and is expected to weaken to a depression by August 6.

Rob Gutro
NASA’s Goddard Space Flight Center

Aug. 04, 2015 – Satellite Sees Tropical Storm Guillermo Nearing Hawaii

Tropical Storm Guillermo continued to creep closer to the Hawaiian Islands on Aug. 4, and NOAA’s GOES-West satellite captured an image of the weakening storm. Westerly wind shear is pushing a stream of clouds to the northeast of the center, making it appears as if Guillermo has a long tail stretching back toward Mexico.

This animation of images captured August 1 to 4 from NOAA’s GOES-West satellite shows Tropical Storm Guillermo weaken from a hurricane on its way toward Hawaii.
Credits: NASA/NOAA GOES Project

Guillermo is getting so close, in fact, that a tropical storm watch is in now in effect for Hawaii county and Maui County, including the islands of Maui, Molokai, Lanai and Kahoolawe. A tropical storm watch means that tropical storm conditions are possible within the watch area, in this case within 36 to 48 hours.

Infrared image of Tropical Storm Guillermo
This infrared image of Tropical Storm Guillermo was taken from NOAA’s GOES-West satellite on Aug. 4 at 1200 UTC (8 a.m. EDT) as it nears Hawaii.
Credits: NASA/NOAA GOES Project

An infrared image of Tropical Storm Guillermo was taken from NOAA’s GOES-West satellite on Aug. 4 at 1200 UTC (8 a.m. EDT) as it neared Hawaii. NOAA manages the GOES series of satellites and the NASA/NOAA GOES Project at NASA’s Goddard Space Flight Center in Greenbelt, Maryland creates images and animations of the GOES satellite data. The image showed that Guillermo appears more elongated, and appears to have developed a “tail.” The tail is actually a stream of clouds being pushed to the northeast of the storm from westerly winds.

At 11 a.m. EDT (5 a.m. HST/1500 UTC) on Aug. 4 the center of tropical storm Guillermo was located near latitude 19.7 north and longitude 148.5 west. Guillermo is moving toward the northwest near 12 mph (19 kph) and the storm is expected to shift to the west-northwest late on Aug. 4 through Aug. 6.

Maximum sustained winds are near 70 mph (110 kph), and little change in strength is expected on Aug. 4 with slow and steady weakening anticipated thereafter. The estimated minimum central pressure is 989 millibars.

On the forecast track, the Central Pacific Hurricane Center forecasts the center of Guillermo is expected to pass 215 miles northeast of Hilo Wednesday afternoon, Aug. 5 and around 165 miles north of Maui Wednesday night.

So what can the Hawaiian Islands expect from Guillermo as it passes by? 

The National Hurricane Center noted that tropical storm conditions are possible on the big island of Hawaii and the islands of Maui, Molokai, Lanai and Kahoolawe in Maui County on Aug. 5. Guillermo is expected to generate between 1 to 3 inches of rainfall with isolated maximum amounts near 7 inches mainly in higher terrain. In addition, rough and large surf is expected along east-facing shores of the main Hawaiian Islands through much of the week.

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Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Aug. 3, 2015 – NASA’s RapidScat Sees Hurricane Guillermo’s Strongest Winds on Western Side

windspeed information on Guillermo
RapidScat gathered data on Guillermo on Sunday, Aug. 2, 2015, at 12 a.m. EDT and saw strongest winds near 30 meters per second (67 mph/108 kph) on the western side of the storm.
Credits: NASA JPL, Doug Tyler

As Hurricane Guillermo continued moving toward the Hawaiian Islands, NASA’s RapidScat instrument that flies aboard the International Space Station analyzed its surface winds. RapidScat found the strongest winds were on the western side of the storm facing the Hawaiian Islands and helping generate rough surf along eastern-facing shores.

RapidScat gathered data on Guillermo on Sunday, Aug. 2, 2015, at 4 p.m. UTC (12 a.m. EDT). At that time the strongest winds were measured near 30 meters per second (67 mph/108 kph) on the western side of the storm. On Aug. 3, hurricane force winds extended outward up to 35 miles (55 km) from the center and tropical storm force winds extend outward up to 130 miles (215 km).

Guillermo continues to kick up rough surf along east facing shores of the Hawaiian Islands.

At 5 a.m. EDT (0900 UTC) on Aug. 3, the center of Hurricane Guillermo was located near latitude 16.2 north…longitude 145.4 west. That puts Guillermo’s center about 680 miles (1,095 km) east-southeast of Hilo, Hawaii, and 890 miles (1,430 km) east-southeast of Honolulu. Maximum sustained winds are near 75 mph (120 kph) and the National Hurricane Center expects the storm to steadily weaken over the next couple of days.

Guillermo was moving toward the west-northwest near 10 mph (17 kph) and this motion is expected to continue over the next couple of days with a slight shift toward the west. The estimated minimum central pressure is 990 millibars.

At 1200 UTC (8 a.m. EDT), Aug. 3, NOAA’s GOES-West satellite captured an infrared image of Guillermo. Guillermo appeared somewhat elongated in the image, and there was no eye visible. 

Guillermo is continuing to move west-northwest and is expected to continue weakening as it runs into increasingly unfavorable atmospheric conditions. The Central Pacific Hurricane Center noted that Guillermo is expected to move near or possibly over the Hawaiian islands on Wednesday, Aug. 5 and Thursday, Aug. 6.

Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.

July 31, 2015 – NASA Gathers Data as Guillermo Becomes the Eastern Pacific’s Fifth Hurricane

NASA's Aqua satellite captured this visible-light image of Hurricane Guillermo on July 30, 2015 at 5:55pm EDT.
NASA’s Aqua satellite captured this visible-light image of Hurricane Guillermo on July 30, 2015 at 21:55 UTC (5:55 p.m. EDT).
Credits: NASA MODIS Response Team

NASA’s Aqua satellite and RapidScat instrument showed that Guillermo was getting better organized and strengthening. On July 31, Guillermo became the fifth of the Eastern North Pacific 2015 hurricane season.

On July 30, the RapidScat instrument that flies aboard the International Space Station measured the storm’s surface winds when it was still a tropical storm. When RapidScat gathered data on the Guillermo, the strongest winds were on the eastern side of the storm, and measured about 24 meters per second (53.6 mph/ 86.4 kph). Those winds continued to increase as the storm became more organized.

On July 30, the RapidScat instrument then Tropical Storm Guillermo's strongest winds on the eastern side of the storm (orange).
On July 30, the RapidScat instrument then Tropical Storm Guillermo’s strongest winds on the eastern side of the storm (orange) near 24 meters per second (53.6 mph/ 86.4 kph).
Credits: NASA/JPL, Doug Tyler

Later in the day, NASA’s Aqua satellite passed over Guillermo as it continued moving west through the Eastern Pacific Ocean. The Moderate Imaging Spectroradiometer (MODIS) instrument aboard Aqua captured a visible-light image on July 30, 2015 at 21:55 UTC (5:55 p.m. EDT).

Forecaster Pasch at the National Hurricane Center noted that imagery showed Guillermo’s cloud pattern continued to become better organized (over the previous day), with well-defined convective banding (of thunderstorms) and a fairly symmetric upper-level outflow pattern. A recent microwave image from the Global Precipitation Measurement (GPM) microwave imager showed a nearly closed low-level eyewall.

At 5 a.m. EDT (0900 UTC) on July 31, satellite images indicated that the maximum sustained winds have increased to near 80 mph (130 km/h) with higher gusts. The center of Hurricane Guillermo was located near latitude 11.5 North and longitude 130.6 West, about 1,526 nautical miles east-southeast of Hilo, Hawaii. Guillermo was moving toward the west-northwest near 16 mph (26 kph), and this general motion is expected to continue through Saturday. The estimated minimum central pressure is 985 millibars.

The hurricane-force winds cover a small area, and extend outward up to 25 miles (35 km) from the center. Tropical storm force winds extend outward up to 115 miles (185 km) from the center.

Pasch noted that Guillermo should be moving over warm waters, and in a moist mid-level environment with moderate vertical wind shear allowing further strengthening over the next couple of days.

Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Tropical Storm Guillermo Forms on the Heels of Tropical Depression 8E–July 30, 2015

this GOES-West infrared image of Guillermo
This GOES-West infrared image of Guillermo, taken on July 30, 2015, at 8 a.m. EDT, shows bands of thunderstorms spiraling around the northern quadrant and wrapping into the low-level center from the west.
Credits: NASA/NOAA GOES Project

As Tropical Depression 8E fades in the Eastern Pacific, Tropical Storm Guillermo formed on its heels. The GOES-West satellite captured an infrared image of Guillermo that showed bands of thunderstorms wrapping into the center.

An infrared image of Guillermo taken from NOAA’s GOES-West satellite on July 30 at 1200 UTC (8 a.m. EDT) showed bands of thunderstorms spiraling around the northern quadrant and wrapping into the low-level center from the west. A fragmented band of thunderstorms from the eastern quadrant also wrapped around the northern quadrant of the storm. The image was created by the NASA/NOAA GOES Project at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

At 11 a.m. EDT (1500 UTC) on July 30, the center of Tropical Storm Guillermo was located near latitude 9.1 North, longitude 127.5 West. Guillermo was about 1,505 miles 2,420 kilometers southwest of the southern tip of Baja California, Mexico and a 1,980 miles (3,190 km east-southeast of Hilo, Hawaii.

Tropical Depression 8E was northwest of Guillermo and was centered near latitude 16.5 North and longitude 138.5 West, about 1,110 miles (1,790 km) east of Hilo, Hawaii.

Guillermo is moving toward the west-northwest near 13 mph (20 kph) and is expected to continue in that direction for the next two days.    

Guollermo’s maximum sustained winds have increased to near 45 mph (75 kph) and additional strengthening is forecast as the storm moves through an environment with light wind shear and warm waters. The National Hurricane Center expects the storm to possibly reach hurricane strength by Friday, July 30.  For updated forecasts, visit the National Hurricane Center web page: http://www.nhc.noaa.gov/  

Rob Gutro
NASA’s Goddard Space Flight Center, Greenbelt, Md.