NASA's TRMM and GPM Satellites Analyze Hurricane Vance Before Landfall
Hurricane Vance was a hurricane on Nov. 4 when the Tropical Rainfall Measuring Mission or TRMM satellite and the Global Precipitation Measurement (GPM) mission satellite passed overhead and measured its rainfall from space. TRMM and GPM revealed areas of heavy rain within the storm before it weakened to a depression and made landfall on Nov. 5.
The TRMM satellite flew over hurricane Vance on Nov. 4 at 0953 UTC (4:53 a.m. EST). Rainfall derived from TRMM's Microwave Imager (TMI) data collected were overlaid on a 1000 UTC (5 a.m. EST) image from NOAA's GOES-West satellite showing cloud cover and extent. The image analysis showed that Vance had a large area of heavy rainfall near the center of the hurricane. Some intense storms in that area were dropping rain at a rate of over 50mm (2 inches) per hour.
Vance's power peaked late on November 3, 2014 with winds of about 95 knots (about 109 mph). Vertical wind shear had started to weaken the hurricane, but Vance was still a powerful category two hurricane on the Saffir-Simpson scale with sustained wind speeds of about 90 knots (about 104 mph).
GPM, the successor to the TRMM satellite had two excellent views of Hurricane Vance on both November 3 at 0031 UTC and on Nov. 4 at 1101 UTC. GPM's Radar (Ku band), that is similar to that used on the TRMM’s satellite, was used to show vertical structure of precipitation at both times. In the first view hurricane Vance was at close to peak power with a well-defined eye. On Nov. 4, the weakening hurricane had a closing eye with much lower thunderstorm tops.
Tropical Depression Vance Makes Landfall
Increasing vertical wind shear weakened Vance from a hurricane to a depression by Nov. 5. In fact, wind shear had increased so much it was blowing at over 50 knots early in the day.
Vance made landfall in western Mexico around 10 a.m. EST today, Nov. 5. At that time, an automated weather station located in the northern part of the state of Nayarit, Mexico, reported a wind gust of 52 mph (84 kph).
On Wednesday, Nov. 5 at 10 a.m. EST (7 a.m. PST/1500 UTC) the center of Tropical Depression Vance was located near latitude 22.7 north and longitude 105.7 west about 55 miles (90 km) southeast of Mazatlan, Mexico. The depression was moving toward the northeast near 13 mph (20 kph) and is expected to continue in that direction taking Vance farther inland. The estimated minimum central pressure is 1005 millibars. Maximum sustained winds had decreased to near 30 mph (45 kph) and Vance is expected to dissipate later today or tonight.
Vance may be dissipating, but the moisture associated with the depression will continue to bring heavy rainfall southeast of its center and across portions of central and northern Mexico and the south-central United States. The ocean swells creating dangerous conditions and rip currents affecting parts of the southwestern Mexico and Baja California Sur coastlines are expected to diminish late on Nov. 5.
Forecaster Cangialosi at NOAA's National Hurricane Center (NHC) noted that by 10 a.m. EST on Nov. Vance's low-level center was becoming elongated, so the cyclone barely met the qualifications for a tropical cyclone.
The moisture that TRMM and GPM saw when Vance was a hurricane will continue to generate heavy rainfall. Even though the tropical cyclone is forecast to dissipate soon, the NHC discussion stated that moisture from the remnants of Vance and the area to its southeast should continue to spread northeastward across Mexico and into the south-central United States. This is producing heavy rains over portions of these areas, which should continue for another day or two.
Rob Gutro/Hal Pierce
SSAI/NASA's Goddard Space Flight Center
Nov. 04, 2014 - NASA's Aqua Satellite Sees Hurricane Vance Headed for Landfall in Western Mexico
NASA's Aqua satellite passed over Vance on Nov. 3 as it started moving in a northeasterly direction toward the northwestern coast of Mexico. On Nov. 4, a Tropical Storm Watch was in effect from Mazatlan northward to Topolobampo, Mexico. Hurricane Vance is forecast to make landfall in northwestern mainland Mexico on Nov. 5.
On Nov. 3 at 20:50 UTC (3:50 p.m. EST) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA's Aqua satellite captured a visible image of Hurricane Vance off Mexico's west coast. The eastern quadrant of the storm covered Socorro Island and stretched as far east as Puerto Vallarta. Around the center of circulation were a thick band of strong thunderstorms that appeared bright white on the MODIS image. Vance's eye was no longer visible as it had filled in with clouds.
The National Hurricane Center (NHC) reported at 10 a.m. EST (7 a.m. PST/1500 UTC) on Nov. 4 that Vance's maximum sustained winds had decreased to 85 mph (140 kph) and rapid weakening was forecast. The center of Hurricane Vance was located near latitude 19.3 north and longitude 109.6 west. That puts the center of Vance about 100 miles (155 km) east-northeast of Socorro Island. Vance is moving toward the north-northeast near 13 mph (20 kph) and is expected to continue for the next couple of days.
Vance is expected to bring large amounts of rainfall to northwestern Mexico. Rainfall totals of 4 to
8 inches with isolated amounts near 12 inches through Wednesday, Nov. 5 over the states of Sinaloa, Nayarit and Durango in western Mexico. NHC noted that swells generated by Vance will be affecting portions of the coast of southwestern Mexico and Baja California Sur today and tonight.
Over the next 24 to 36 hours, Vance could weaken to a tropical depression by the time it reaches the coast of Mexico. Landfall is expected mid-day Wednesday, Nov. 5.
NASA's Goddard Space Flight Center
[image-69]Nov. 03, 2014 - Hurricane Vance Dwarfs Developing Low Pressure Area
NOAA's GOES-West satellite captured an image of Hurricane Vance and a much smaller developing low pressure area in the Eastern Pacific Ocean on Nov. 3. Vance's tropical-storm force winds extended to about 250 miles in diameter.
NOAA's GOES-West satellite captured an infrared image of the Eastern Pacific that showed Hurricane Vance was a couple of times larger than the developing low pressure area known as System 94E to the southeast of the hurricane. In the GOES image, taken Nov. 3 at 1200 UTC (7 a.m. EST/4 a.m. PST) clouds and showers extending from Vance's northern quadrant stretched over northwestern Mexico.
At 7 a.m. PST, the center of Hurricane Vance was located near latitude 15.3 north and longitude 110.6 west. That puts Vance's center about 490 miles (785 km) west-southwest of Manzanillo, Mexico. Vance was moving toward the north-northwest near 12 mph (19 kph). Vance is expected to turn north then north-northeast by Nov. 4. Maximum sustained winds were near 105 mph (165 kph) and weakening is expected to begin today.
Moisture spreading northward ahead of Vance is expected to produce rainfall totals of 4 to 8 inches with Isolated amounts near 12 inches through Wednesday over the states of Sinaloa, Nayarit and Durango in western Mexico. Rough ocean swells are expected along the coast of southwestern Mexico and Baja California Sur tonight and Nov. 4.
Forecaster Brown at the National Hurricane Center (NHC) noted that "Recent microwave images show that the inner core of Vance remains vertically aligned (stacked on top of each other), however, the outflow is becoming increasingly restricted over the southwestern portion of the circulation due to southwesterly shear." That vertical wind shear over Vance is forecast to dramatically increase during the next 24 to 48 hours which means that the storm is expected to weaken.
The NHC believes that Vance has peaked in intensity and will begin to rapidly weaken in the next couple of days as it curves to the coast near the border of Mexico and California.
NASA's Goddard Space Flight Center
Oct. 31, 2014 - Tropical Storm Vance's Center Looks Like a Pumpkin to NASA's Terra Satellite
Tropical Depression 21E strengthened overnight on Oct. 30 and by Halloween morning, Tropical Storm Vance was haunting the waters of the Eastern Pacific Ocean. In a false-colored infrared image from NASA's Terra satellite on Oct. 31, the strong thunderstorms around the center resemble a pumpkin.
Tropical Depression 21E formed on Oct. 30 after struggling for days as a low pressure area. Just a day later it strengthened into a tropical storm and was renamed Vance.
NASA's Terra satellite passed over Vance on October 31 at 4:55 UTC (12:55 a.m. EDT) – the witching hour – and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard Terra captured infrared data. That infrared data was false-colored when the image was created. High, strong thunderstorms with cold cloud top temperatures that circled the center were false-colored in an orange-red color, and resembled the shape of a pumpkin with a stem!
At 5 a.m. EDT, Tropical Storm Vance's maximum sustained winds were near 45 mph (75 kph) and is expected to strengthen gradually. Vance was centered near latitude 10.5 north and longitude 101.0 west. That's about 450 miles (720 km) south of Acapulco, Mexico. Vance is moving toward the west-southwest near 3 mph (6 kph) and is forecast to turn to the west and west-northwest on Nov. 1.
National Hurricane Center Forecaster Dan Brown noted that Vance's center was near the southern edge of the large mass of deep convection due to moderate south-southwesterly shear. The shear and some dry low- to mid-level air are expected to continue to affect the tropical cyclone during the next 12 to 24 hours, and only gradual strengthening is expected during that time.
Most of the intensity guidance shows Vance becoming a hurricane in 2 to 3 days.
NASA's Goddard Space Flight Center
[image-50]Oct. 30, 2014 - Twenty-first Eastern Pacific Tropical Depression Born on Oct. 30
NOAA's GOES-West satellite captured an image of the birth of the Eastern Pacific Ocean's twenty-first tropical depression, located far south of Acapulco, Mexico.
NOAA's GOES-West satellite gathered infrared data on newborn Tropical Depression 21E (TD 21E) and that data was made into an image by NASA/NOAA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland. At 1200 UTC (9 a.m. EDT), the GOES-West image showed that thunderstorms circled the low-level center and extended northeast of the center indicating that southwesterly wind shear was affecting the storm.
At 11 a.m. EDT (1500 UTC), maximum sustained winds were near 35 mph (55 kph) and some slow strengthening is forecast during the next 48 hours. TD 21E was centered near latitude 11.5 north and longitude 100.9 west. That's about 380 miles (610 km) south of Acapulco, Mexico. TD 21E was moving west at 6 mph (9 kph) and is expected to turn to the southwest on Friday, Oct. 31, followed by a turn back west on Nov. 1. The estimated minimum central pressure is 1007 millibars.
Forecaster Blake of NHC noted that although the depression is over warm water, southwesterly shear and dry air in the low- to mid-levels are expected to continue for the next day or two which will make any strengthening occur slowly.
The depression is forecast to turn west-southwestward and then southwestward over the next day and a half, and become a tropical storm.
NASA's Goddard Space Flight Center