Weather

Colorado State experts continue to predict below-average Atlantic hurricane season

August 10th, 2014 at 9:18 am by under Weather

(Courtesy Colorado State University, July 31, 2014)

ATLANTIC BASIN HURRICANE FORECAST FOR 2014

(Average) Predicted - Numbers in ( ) represent medians based on 1981-2010 data.

Named Storms (12)* 10
Named Storm Days (60.1) 40
Hurricanes (6.5) 4
Hurricane Days (21.3) 15
Major Hurricanes (2.0) 1
Major Hurricane Days (3.9) 3
Accumulated Cyclone Energy (92) 65
Net Tropical Cyclone Activity (103%) 70

FORT COLLINS -  Colorado State University researchers continue to predict a below-average hurricane season for the Atlantic basin in 2014, citing exceptionally unfavorable hurricane formation conditions in the tropical Atlantic combined with the likely development of a weak to moderate El Niño event. The below-average prediction is largely due to strong vertical wind shear, dry mid-level air and cool sea surface temperature anomalies in the tropical Atlantic and Caribbean.

The CSU Tropical Meteorology Project team is calling for a total of 10 named storms during the Atlantic hurricane season, June 1 to Nov. 30. Of those, researchers expect four to become hurricanes and one to reach major hurricane strength (Saffir/Simpson category 3-4-5) with sustained winds of 111 miles per hour or greater.

Hurricane Arthur formed in early July, so an additional nine named storms and three hurricanes are predicted for the remainder of the hurricane season.

The team bases its forecasts on over 60 years of historical data that include Atlantic sea surface temperatures, sea level pressures, vertical wind shear levels (the change in wind direction and speed with height in the atmosphere), El Niño (warming of waters in the central and eastern tropical Pacific), and other factors.

“So far, the 2014 season is exhibiting characteristics similar to the 1957, 1986, 1993, 2002, and 2009 hurricane seasons, all of which had below-normal hurricane activity,” said Phil Klotzbach, lead author of the report.

(more…)


August bird forecast

August 8th, 2014 at 3:42 pm by under Weather

What to watch for in August: Duck!

Here’s the Central Texas bird forecast for the month, courtesy of Travis Audubon. Learn more about Central Texas birds and bird-related events for all ages at travisaudubon.org or by calling 512-300-BIRD. Travis Audubon is on Twitter and Facebook. Follow us on Twitter @TravisAudubon and give us a like at www.facebook.com/travisaudubon.

Black-bellied Whistling Duck photo by Captain Tom via Flickr/Creative Commons

Black-bellied Whistling Duck photo by Captain Tom via Flickr/Creative Commons

Think pink

Black-bellied Whistling Ducks, which are year-round residents in Central Texas, are in ready view this month. Their numbers are higher because there are many youngsters now accompanying their parents. Besides having black bellies, these noisy ducks have bright pink bills and long pink legs. They descend in flocks into fields and onto golf course water features and retention ponds. They are shaped like geese, but their coloring — gray faces, brown backs and brown mohawk-style stripes on their heads — makes them distinctive. They also have distinctive white wing stripes that are visible during flight. And yes, they have a high-pitched whistling call.

Spot these ducks at any of the larger retention ponds around town, in particular the pond in front of the Walnut Creek Wastewater Treatment plant and the pond near the shopping areas of Sunset Valley. Learn more about birding at the Walnut Creek plant at http://www.tpwd.state.tx.us/publications/pwdpubs/pwd_br_w7000_0328/east.
 
A Swift Night Out

Purple Martins aren’t the only species to gather in large groups before heading south. Chimney Swifts do it too, just a little later in the summer and in numerous locations across Austin. Join us as we participate in A Swift Night Out!, an annual continent-wide event of the Driftwood Wildlife Association and our Chimney Swift heroes Paul and Georgean Kyle. The event, held over one weekend in August and one weekend in September, raises awareness about swifts and plays a vital role in determining population trends. Check out http://www.chimneyswifts.org/ for more information. Watching the swifts gather and then counting them as they descend into a chimney is fun and a challenge since many of them decide to descend nearly simultaneously. Lawn chairs and binoculars are recommended. We’ll have teams at several roost sites on Friday, Saturday and Sunday nights, August 8 through 10. Registration is recommended, but there is no limit to the number of participants, so join us for one night or all three nights! Check out the map at http://goo.gl/maps/kv6fC for the locations (you can zoom in and click on the blue pins to display the address). Contact Shelia Hargis at Shelia.hargis@gmail.com or 512-294-0272 to register. (Also plan to join us in September: September 12-14.)
Field Trips — Beginners welcome. Check the Travis Audubon website for details.

http://travisaudubon.org/get-outdoors/field-trips

Monthly Bird Count at Hornsby Bend
Saturday, August 9, 7 a.m. & 4 p.m.

A Swift Night Out! – Multiple Chimney Swift Roosts Across Austin
Sunday, August 10, 7:30 to 8:30 pm

Chimney Swift Party – Brentwood Elementary School, 6700 Arroyo Seco
Saturday, August 16, 7:30 to 8:30 p.m.

Hornsby Bend Monthly Bird Walk
Saturday, August 16, 7:30 to 11 a.m.

Commons Ford Monthly Walk
Sunday, August 17, 7 to 11 a.m.

Two-hour Tuesday! at Hornsby Bend led by Ken Zaslow
Tuesday, August 26, 7:30 to 9:30 a.m.

Compiled by Travis Audubon volunteers Jane Tillman and Raeanne Martinez


Strongest tropical storm on record pounds Hawaii’s Big Island

August 8th, 2014 at 2:24 pm by under Weather

Courtesy: Dr. Jeff Masters, Weather Underground

Tropical Storm Iselle made landfall along the southeast shore of Hawaii’s Big Island near 9 am EDT (3 am HST) as a tropical storm with 60 mph winds. Iselle is only the second tropical storm on record to hit the Big Island, and was the strongest. The Big Island’s other tropical storm was an unnamed 1958 storm that had sustained winds of 50 mph at landfall. Iselle is just the fourth tropical storm or hurricane to make a direct hit on any Hawaiian Island since accurate records began in 1949. Iselle is bringing torrential rains to the Big Island, where a rain gauge near Pahala indicated rain rates at nearly 4 inches per hour. A Flash Flood Warning is in effect for this area, and all of the Hawaiian Islands are under a Flash Flood Watch today. It is too early to assess what damage Iselle may have done, but the NWS reported roofs flying off and downed trees in Hawaiian Paradise Park, and at least 21,000 customers were without power early Friday morning on the Big Island. Some peak wind gusts and rainfall amounts on the Big Island so far from Iselle, as of 11 am EDT (5 am HST) Friday:

Hilo Airport: 32 mph gusting to 54 mph at 11 pm HST, 2.33″ of rain
Kona Airport: 32 mph gusting to 45 mph at 1:53 pm HST
Bradshaw AFB: 23 mph gusting to 43 mph at 5 am HST, .23″ of rain

The winds on top of the highest point in Hawaii, the Big Island’s Mauna Kea, elevation 13,796′ (4,205 m), gusted up to 72 mph this morning at the University of Hawaii 88″ telescope.

Five stations on the windward side of the Big Island had received at least 10″ of rain in 24 hours as of 5 am HST Friday, according the NWS Hawaii rainfall summary:

Hakalau: 10.70″
Pua Akala: 10.19″
Saddle Quarry: 11.39″
Glenwood: 10.63″
Kulani NWR: 11.19″


Figure 1. Radar image from the South Hawaii radar at 7:49 am EDT August 8, 2014 of Tropical Storm Iselle near landfall on the Big Island. The radar beam is being intercepted by the high mountains of Hawaii, and cannot “see” to the northwest.


Figure 2. True-color MODIS image of Hurricane Iselle from 23:15 UTC (7:15 pm EDT) August 7, 2014. At the time, the outer spiral bands of the 80 mph Category 1 hurricane were spreading over the Big Island of Hawaii. Image credit: NASA.

Forecast for Iselle
Friday morning satellite images showed that Iselle’s thunderstorms continued to be very vigorous with cold cloud tops, but interaction with the high peaks of Mauna Loa and Mauna Kea had severely disrupted the circulation. The storm will have difficultly re-organizing once its center emerges over the ocean, since wind shear is a very high 25 – 30 knots, and water vapor satellite images are showing a lot of dry air on the west side of the Big Island. The shear and dry air should be enough to destroy Iselle by Saturday afternoon.


Figure 3. True-color MODIS image of Hurricane Julio from 19:30 UTC (3:30 pm EDT) August 7, 2014. At the time, Julio was a Category 2 hurricane with 105 mph winds. Image credit: NASA.

Hurricane Julio expected to skirt Hawaii
Hurricane Julio intensified into a Category 3 hurricane with 115 mph winds overnight, becoming the fifth major hurricane in the Eastern Pacific so far in 2014. This is an inordinately high number of major hurricanes–usually, the Eastern Pacific has only three major hurricanes in an entire season, and just one by August 8. Though Julio had weakened to a Category 2 storm with 105 mph winds on Friday morning, satellite loops show that Julio still has an impressive area of heavy thunderstorms and well-formed eye, though the cloud tops are warming, indicating weakening. The storm should be able to take advantage of light to moderate wind shear and marginally warm sea surface temperatures near 26°C and maintain at least Category 1 status until Sunday morning. Fortunately, it is looking increasingly likely that Julio will not have a major impact on the Hawaiian Islands. The Friday morning runs of our top track models all predicted that the center of Julio would pass 100 – 300 miles northeast of the Hawaiian Islands on Sunday. On this path, Julio’s core of heavy rains and wind would miss the islands, and high surf would be the main impact of the storm. The edge of Julio’s cone of uncertainly for Sunday no longer lies over the islands.

Super Typhoon Genevieve not a threat to land
Farther west in the Pacific, what was formerly Hurricane Genevieve is now Super Typhoon Genevieve, after the storm crossed the International Date Line from east to west early Thursday. There is no difference between a North Pacific hurricane and a typhoon other than its location–if the storm is west of the Date Line, it is called a typhoon, and if it is east of the Date Line, it is called a hurricane. This only applies to storms in the Pacific in the Northern Hemisphere; in the Southern Hemisphere’s Pacific Ocean, everything is called a Tropical Cyclone regardless of which side of the Date Line it falls on. Genevieve put on an amazing display of rapid intensification, going from a tropical storm with 60 mph winds to a Category 5 super typhoon with 160 mph winds in just 27 hours, from 09 UTC August 6 to 12 UTC August 7. Genevieve spent 24 hours as a Category 5 storm, before weakening slightly to a 150 mph Category 4 storm at 8 am EDT Friday. Satellite images still show an very impressive storm with a large eye surrounded by a giant area of intense eyewall thunderstorms with very cold cloud tops. Fortunately, Genevieve is not expected to threaten any land areas.


El Niño still expected, but odds lowered

August 7th, 2014 at 2:14 pm by under Weather

(Climate Central)  The El Niño that seems to be trying to form in the tropical Pacific Ocean is looking a little less likely now, though the chances of it developing are still double the normal odds, forecasters said in the latest monthly update on the cyclical climate phenomenon, released Thursday.

The climate impacts typically associated with an El Niño during the months of December, January, and February.
Click image to enlarge. Credit: NOAA

That update lowered the odds of an El Niño occurring in fall and early winter to 65 percent, down from 80 percent last month. But “we’re still fairly confident that El Niño will come,” said Michelle L’Heureux a meteorologist with the National Oceanic and Atmospheric Administration’s Climate Prediction Center, who puts out the El Niño forecasts along with the International Research Institute for Climate and Society at Columbia University.

If and when the El Niño forms, it would influence weather and climate patterns in particular regions around the globe, for example, tamping down on hurricane activity in the Atlantic Ocean. Depending on its strength, it could also drive up global temperatures enough on top of the rise from human-induced warming to send 2015 into the record books.

RELATED How Will We Know When El Niño Finally Arrives?
El Niño Expected to Limit 2014 Hurricane Season
Why Do We Care So Much About El Niño?

While above-normal sea surface temperatures in the far eastern tropical Pacific — a hallmark of an El Niño event — have persisted, the warmth in other key surface regions and below the surface has ebbed. The shifts in atmospheric patterns that accompany an El Niño also have yet to materialize. These factors combined caused forecasters to lower the odds.

The updated probabilities mean that instead of a 4-in-5 chance that an El Niño would materialize, there is now a 2-in-3 chance it would, L’Heureux said.

But even a 65 percent chance is double the typical odds of seeing an El Niño in winter, she said.

Forecasters think any El Niño that does develop will be a weak to moderate in strength, though a strong event can’t be completely ruled out. But going from such a current weak showing to a strong El Niño “would certainly be unprecedented,” L’Heureux told Climate Central.

El Niño is the warm phase of a larger cycle called the El Niño-Southern Oscillation, which includes its counterpart La Niña. Normally, the western tropical Pacific is warmer than the east, but during an El Niño, this pattern reverses. The trade winds that normally blow from east to west weaken or even reverse.

L’Heureux and other forecasters have been watching the development of this potential El Niño since issuing an El Niño Watch in March. In April, the situation looked ripe for an El Niño to form this summer, as a huge plume of warm water, called a Kelvin wave, slid through the ocean and brought exceptionally warm waters to the eastern Pacific. The development drew comparisons to the strong El Niño of 1997-1998.

Animation of subsurface temperature anomalies in the tropical Pacific Ocean.
Credit: NOAA.

But while the ocean looked set for the El Niño, the atmosphere wasn’t playing along, and storm activity developing over Indonesia, which normally dries during an El Niño.

Over the past month, the pool of warm water below the ocean’s surface (and at an area of the ocean surface called the Niño 3.4 region) has dissipated, prompting L’Heureux and her colleagues to say ENSO is still in its neutral phase.

The cool-down in the Niño 3.4 region was actually anticipated by the ENSO forecast models, and is consistent with the upwelling phase of the Kelvin wave, when some of the excess heat dissipates. The fact that they caught that slight dip gives L’Heureux and her colleagues more confidence that the models are on target in their continued projections that an El Niño will actually develop.

“To me, that enhances their credibility,” L’Heureux said.

And while she is loathe to compare any one El Niño to another since the record of well-observed El Niños is short, L’Heureux said that other El Niños saw similar dips in sea surface temperatures around this time in the season before finally forming. Of the seven El Niños that have formed since 1990 (as far back as weekly sea surface temperature records go), three — 1994, 2004 and 2006 — saw similar drops, all of which happened in late June and July.

“So there is precedent for this, I guess, sort of summertime lull,” L’Heureux said. And summer is actually a tricky time to get the atmosphere and ocean to act in sync, she added, so it could simply be seasonal effects keeping the El Niño from moving forward.

While forecasters are still betting an El Niño will happen, L’Heureux did say she keeps looking back at the data from 2012, when what forecasters thought would be an El Niño completely fizzled. They called off that watch when the sea surface temperatures were near average across the whole tropical Pacific and the models were “starting to tank,” she said. “And we really haven’t reached that point” with this event, she added.

The models suggest that some of the lost heat will come back, but if the atmosphere doesn’t start playing along and the heat doesn’t regenerate, “the models will catch on,” L’Heureux said.


Hurricane Scientists Bring a New Wave of Technology to Improve Forecasts

August 7th, 2014 at 1:13 pm by under Weather

(NOAA)  Scientists at NOAA’s Atlantic Oceanographic and Meteorological Laboratory are at the forefront of hurricane research to improve track and intensity forecasts. Every hurricane season they fly into storms, pour over observations and models, and consider new technological developments for how to enhance NOAA’s observing capabilities. The 2014 hurricane season will provide an opportunity to test some of the most advanced and innovative technologies, including unmanned hurricane hunter aircraft and sea gliders, which will help scientists better observe and, eventually, better predict a storm’s future activity.

The game plan: where we are and where we need to be

NOAA’s Aircraft Operations Center (AOC) maintains two P-3 Orions and a Gulfstream IV jet for hurricane observations. To collect data, NOAA’s hurricane researchers fly aboard these aircraft into and around the periphery of storms. A primary tool they use for measuring the hurricane environment is the dropsonde, a lightly weighted cylindrical tube equipped with a parachute and global positioning system technology. Dropsondes transmit their position every half second as they drift through a storm. These mini-weather stations are deployed from the belly of the aircraft and fall towards the ocean, sending data such as pressure, temperature, wind speed, wind direction, and moisture to scientists aboard the hurricane hunter aircraft.

 

NOAA's P-3 Orion an dG-IV hurricane hunter aircraft

NOAA’s P-3 Orion and G-IV jet. Photo credit: NOAA        

While dropsondes are an excellent tool for measuring a storm’s atmospheric environment, their spatial coverage is limited. Dropsondes essentially obtain vertical profiles of a storm at discrete points. Other instruments on the aircraft measure storm properties at altitudes as great as 60,000 feet. However, NOAA’s hurricane hunter aircraft are unable to fly below 5,000 feet due to the extreme turbulence occurring between the ocean and atmosphere. This leaves a gap in the opportunity to collect potentially important data from the lower part of the storm, which may be essential to increasing the understanding of intensity change.

Congressional funding supports new unmanned aircraft

Post-Hurricane Sandy federal funding, the Disaster Relief Appropriations Act of 2013, provided NOAA with the opportunity to test new technology in hopes of better understanding and evaluating storm physics that drive intensity change. An unmanned weather drone, called the Coyote, will do just that.  The Navy originally designed the Coyote for maritime surveillance. NOAA plans to transition this unique platform into a “smart sonde” that can be used for hurricane science. During the 2014 hurricane season, the Small Unmanned Aircraft Vehicle Experiment will test the capability of the Coyote in storms, observing how well it handles severe winds and the harsh hurricane environment.

 

Dr. Joe Cione holds the Coyote UAS

Dr. Joe Cione of AOML’s Hurricane Research Division displays the Coyote UAV

 Scientists will deploy the seven pound unmanned aircraft from the P-3 Orion in the same way as the dropsondes. However, instead of drifting downward towards the ocean surface, the Coyote will open its six-foot wingspan and fly through the storm.  It can be controlled from miles away but will typically be piloted by scientists onboard the P-3s. Its relative lightweight design requires the Coyote to fly with the wind currents, but it will be directed up, down, and sideways to navigate specific flight patterns to measure the inner core and lowest altitudes of the storm.

Hurricanes are fueled by warm ocean water, and vital information needed to better understand and predict intensity change may rest close to the sea surface where manned aircraft cannot fly and the dropsondes only pass through for a few seconds. With its ability to fly for two hours in this region, the Coyote provides the opportunity for much more complete data collection, in comparison to the traditional dropsonde.

Adding a new twist to existing technology

The traditional dropsone itself will also receive an upgrade for the 2014 season with the addition of a sensor to measure sea surface temperature at splashdown. This additional last data point will provide a critical piece of information at the air-sea interface, the environment where energy transfer occurs and is most challenging to observe in a hurricane environment.

(image credit: NCAR)
 dropsonde

Diving into the ocean to improve hurricane forecasts

The 2014 season will also feature two sea gliders, remotely operated profiling instruments that dive below the ocean surface and then resurface to transmit observations of temperature and salinity. NOAA is testing two ocean gliders in critical hurricane regions of the Caribbean north and south of Puerto Rico. The gliders were deployed in July and will be recovered at the end of hurricane season.  The gliders will profile the upper ocean about 10 times daily, diving to a depth of 1,000 feet and collecting data as they ascend. When a sea glider breaks the surface, its data will be transmitted to AOML and made available in near-real time via the web.

 

Sea Gliders ready for deployment off of Puerto Rico

Two gliders ready for deployment from the R/V Sultana, off the coast of Puerto Rico (credit: NOAA/AOML)

In addition to these new technologies, the Disaster Relief Appropriations Act of 2013 also provided funding to assess the impact of these and other data in hurricane forecast models. AOML will make use of its Observing System Simulation Experiment expertise to evaluate how such ocean observations can best improve hurricane forecasts of track and intensity change.

The Hurricane Research Division is one of AOML’s three scientific research divisions. Scientists with HRD, and its precursors, have been flying into hurricanes for almost 60 years and regularly collaborate with other federal, university, and international  partners to leverage that expertise to advance hurricane science and forecasting globally. Follow the latest HRD activities during this research season on Twitter or by visiting the division website.


Updated Atlantic Hurricane Season Outlook Released

August 7th, 2014 at 12:29 pm by under Weather

noaa_logo

NOAA’s updated Atlantic hurricane season outlook calls for an increased chance of a below-normal season

 

August 7, 2014
Forecasters with NOAA’s Climate Prediction Center raised the likelihood for a below-normal season in today’s update to the Atlantic Hurricane Season Outlook. The update predicts a 70 percent chance of a below-normal season, a 25 percent chance of a near-normal season and only a five percent chance of an above-normal season. The probabilities in the initial outlook issued on May 22 were 50 percent, 40 percent and 10 percent, respectively.
“We are more confident that a below-normal season will occur because atmospheric and oceanic conditions that suppress cyclone formation have developed and will persist through the season.” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, a division of the National Weather Service. “Nonetheless, tropical


storms and hurricanes can strike the U.S. during below-normal seasons, as we have already seen this year when Arthur made landfall in North Carolina a
s a category-2 hurricane. We urge everyone to
remain prepared and be on alert throughout the season.”
The primary factors influencing the increased chance of a below-normal season are:
  • Overall atmospheric conditions are not favorable for storm development. This includes strong vertical wind shear, a weaker West African monsoon, and the combination of increased atmospheric stability and sinking motion. These conditions mean fewer tropical systems are spawned off the African coast, and those that do form are less likely to become hurricanes. These conditions are stronger than originally predicted in May and are expected to last mid-August through October, the peak months of the hurricane season;
  • Overall oceanic conditions are not favorable for storm development. This includes below-average temperatures across the Tropical Atlantic, which are exceptionally cool relative to the remainder of the global Tropics. This cooling is even stronger than models predicted in May and is expected to persist through the hurricane season; and
  • El Niño is still likely to develop and to suppress storm development by increasing vertical wind shear, stability and sinking motion in the atmosphere.
The updated hurricane season outlook, which includes the activity to-date of hurricanes Arthur and Bertha, predicts a 70 percent chance of the following ranges: 7 to 12 named storms (top winds of 39 mph or higher), including 3 to 6 hurricanes (top winds of 74 mph or higher), of which 0 to 2 could become major hurricanes (Category 3, 4, 5; winds of at least 111 mph).
These ranges are centered below the 30-year seasonal averages of 12 named storms, six hurricanes and three major hurricanes. The initial outlook in May predicted 8 to 13 named storms, 3 to 6 hurricanes and 1 to 2 major hurricanes.

The Atlantic hurricane region comprises the North Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea. NOAA’s seasonal hurricane outlook is not a hurricane landfall forecast; it does not predict how many storms will hit land or where a storm will strike. Forecasts for individual storms and their impacts will be provided throughout the season by NOAA’s National Hurricane Center.

 

The Climate Prediction Center also continued the El Niño watch today in its scheduled monthly El Niño/Southern Oscillation Diagnostic Discussion. Forecasters note that although sea surface temperatures across the central equatorial Pacific have recently returned to near average, this cooling is expected to be temporary. El Niño is now favored to emerge during August-October, and to peak at weak strength during the late fall and early winter. The likelihood of El Niño during August-October has decreased to 55 percent (from 75 percent in May), and its likelihood during the fall and winter has decreased to about 65 percent (from near 80 percent).


Rare twin hurricanes heading toward Hawaii

August 6th, 2014 at 4:10 pm by under Weather

Courtesy Dr. Jeff Masters, Weather Underground

Rare twin Category 1 hurricanes are nearing Hawaii as Hurricane Iselle, with 85 mph winds, and Hurricane Julio, with 75 mph winds, steam west-northwest towards the islands. Both hurricanes are expected to weaken to tropical storms before they affect Hawaii. Iselle is the bigger danger, as it is expected to make a direct hit on Thursday evening, while Julio’s center is expected to pass about 100 miles to the northeast of the islands on Sunday. Satellite images show that Iselle has weakened significantly over the past day. Though the hurricane still has a prominent eye, the eyewall’s heavy thunderstorms are much reduced in intensity and areal coverage, due to wind shear and dry air. A new Air Force hurricane hunter aircraft is scheduled to be in the storm near 1 pm EDT Wednesday, and the NOAA jet will fly another dropsonde mission Wednesday evening. The outer spiral bands of Iselle were not yet visible on Hawaii radar on Wednesday morning, but should come into view late Wednesday night.


Figure 1. Official forecast and uncertainty cones for Hurricane Iselle and Hurricane Julio, made at 11 am EDT Wednesday August 6, 2014. Image taken from our wundermap with the Tropical layer turned on.

Forecast for Iselle
Wind shear is expected to stay moderate until Iselle reaches the islands Thursday evening. Ocean temperatures will remain a marginal 26°C, and the atmosphere surrounding the storm will steadily dry, resulting in continued weakening of Iselle. Just how weak the storm will be when it arrives in the islands Thursday afternoon and evening is a matter of considerable disagreement amount our top intensity models; the Wednesday morning runs of the LGEM, GFDL, and HWRF models predicted a strong tropical storm or weak Category 1 hurricane with 65 – 75 mph winds at 8 pm EDT Thursday, while the DSHIPS model predicted a much weaker system with 45 – 50 mph winds. Historically, only one tropical storm and no hurricanes approaching from the east have ever hit the islands, and this climatology would argue for a weaker Iselle on Thursday evening. The official CPHC forecast for a 60 – 65 mph tropical storm is reasonable, but Iselle could easily be a 50 – 55 mph storm Thursday evening. Regardless, the main threat from Iselle will be heavy rains leading to flash flooding and mudslides, and the storm will be capable of generating dangerous heavy rains when it reaches the islands. The Wednesday morning 06Z run of the HWRF model predicted that Iselle would dump widespread rains of 8 – 16″ over the Big Island, with some regions seeing 16 – 24″. This rainfall forecast was for a 75 mph Category 1 hurricane hitting the Big Island, and is likely to be too high. Some minor wind damage is also possible from Iselle; the 11 am EDT Wednesday Wind Probability Forecast from Central Pacific Hurricane Center (CPHC) gave Hilo on the Big Island a 64% chance of experiencing tropical storm-force winds of 39+ mph, and a 5% chance of hurricane-force winds. These odds were 32% and 0%, respectively, for Honolulu. High surf of 10 – 20′ and higher will also pound the islands, causing erosion problems and coastal flooding.


Figure 2. Predicted rainfall along the track of Hurricane Iselle from the 06Z (2 am EDT) Wednesday August 6, 2014 run of the HWRF model. The model forecasts that Iselle will be a weak Category 1 hurricane with 75 mph winds when it hits the Big Island Thursday evening. Widespread rains of 8 – 16″ are predicted over the Big Island, with some regions seeing 16 – 24″. This rainfall forecast will be too high if Iselle is considerably weaker, as the official CPHC forecast is predicting. Image credit: NOAA/EMC/NCEP/NWS.

Julio becomes a hurricane
Hawaii’s other hurricane threat is Hurricane Julio, which intensified to a Category 1 hurricane with 75 mph winds at 5 am EDT on Wednesday. Julio’s ascension to hurricane status now gives the Eastern Pacific 10 named storms, 5 hurricanes, and 3 intense hurricanes so far in 2014. On average, we expect to see just 6 named storms, 3 hurricanes, and 1 intense hurricane by August 6. Satellite loops show that Julio is not very impressive yet, with only a modest area of heavy thunderstorms and no eye. The storm should be able to take advantage of light to moderate wind shear and marginally warm sea surface temperatures near 26°C to intensify 5 – 15 mph by Thursday. Higher wind shear and drier air should induce weakening beginning on Friday. The models have been increasingly enthusiastic about Julio taking a bend to the right in its track this weekend, putting the center of the storm about 100 miles northeast of the Hawaiian Islands on Sunday. On this path, Julio’s core of heavy rains of 8 – 16″ would miss the islands, and high surf would be the main impact of the storm. The edge of Julio’s cone of uncertainly for Sunday still lies over the islands, so we cannot yet be confident of this track, but I am cautiously optimistic that Hawaii will avoid torrential rains from Julio falling upon soils already saturated by Iselle.


Figure 3. Tracks of all tropical cyclones (tropical depressions, tropical storms, and hurricanes) to pass within 100 miles of the Hawaiian Islands, 1949 – 2013. Hurricanes approaching from the east typically fall apart before they reach Hawaii due to the cool waters and dry air that lie to the east of the islands. Only one named storm approaching from the east has hit the islands since 1949, an unnamed 1958 tropical storm that hit the Big Island. Hurricanes approaching from the south represent the biggest danger to the islands, due to the warmer waters and more unstable air present to the south. The only two major hurricanes to have affected the islands since 1949, Hurricane Iniki of 1992 and Hurricane Dot of 1959, both came from the south. Image credit: NOAA/CSC.

Hawaii’s hurricane history
On average, between four and five tropical cyclones are observed in the Central Pacific every year. This number has ranged from zero, most recently as 1979, to as many as eleven in 1992 and 1994. August is the peak month, followed by July, then September. Tropical storms and hurricanes are rare in the Hawaiian Islands. Since 1949, the Hawaiian Islands have received a direct hit from just two hurricanes–Dot in 1959, and Iniki in 1992. Both hit the island of Kauai. Only one tropical storm has hit the islands since 1949–an unnamed 1958 storm that hit the Big Island. A brief summary of the three most significant hurricanes to affect Hawaii in modern times:

September 1992: Hurricane Iniki was the strongest, deadliest, and most damaging hurricane to affect Hawaii since records began. It hit the island of Kauai as a Category 4 on September 11, killing six and causing $2 billion in damage.

November 1982: Hurricane Iwa was one of Hawaii’s most damaging hurricanes. Although it was only a Category 1 storm, it passed just miles west of Kauai, moving at a speed of nearly 50 miles per hour (80 km/h). Iwa killed one person and did $250 million in damage, making it the second most damaging hurricane to ever hit Hawaii. All the islands reported some surf damage along their southwest facing shores, and wind damage was widespread on Kauai.

August 1959: Hurricane Dot entered the Central Pacific as a Category 4 hurricane just south of Hawaii, but weakened to a Category 1 storm before making landfall on Kauai. Dot brought sustained winds of 81 mph with gusts to 103 mph to Kilauea Light. Damage was in excess of $6 million. No Dot-related deaths were recorded.


NASA Mars Curiosity Rover: Two Years and Counting on Red Planet

August 5th, 2014 at 8:18 pm by under Weather

Curiosity Tracks in 'Hidden Valley' on Mars

This image from the Navigation Camera on NASA’s Curiosity Mars rover shows wheel tracks printed by the rover as it drove on the sandy floor of a lowland called “Hidden Valley” on the route toward Mount Sharp. The image was taken on Aug. 4, 2014.
› Full image and caption

NASA’s most advanced roving laboratory on Mars celebrates its second anniversary since landing inside the Red Planet’s Gale Crater on Aug. 5, 2012, PDT (Aug. 6, 2012, EDT).

During its first year of operations, the Curiosity rover fulfilled its major science goal of determining whether Mars ever offered environmental conditions favorable for microbial life. Clay-bearing sedimentary rocks on the crater floor in an area called Yellowknife Bay yielded evidence of a lakebed environment billions of years ago that offered fresh water, all of the key elemental ingredients for life, and a chemical source of energy for microbes, if any existed there.

“Before landing, we expected that we would need to drive much farther before answering that habitability question,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology, Pasadena. “We were able to take advantage of landing very close to an ancient streambed and lake. Now we want to learn more about how environmental conditions on Mars evolved, and we know where to go to do that.”

(more…)


Tuesday Morning Tropical Update

August 5th, 2014 at 6:09 am by under Weather

Here is the latest from the National Hurricane Center, as they discuss the three current storms that are churning in the Atlantic and Pacific Oceans.  Also, there is a disturbance in the Pacific that is following the same line as the other 2 storms, and is expected to develop in the near future.  We’ll briefly touch on that as well.  

We start with Bertha in the Atlantic:

Bertha Now

SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...33.4N 72.9W
ABOUT 475 MI...765 KM W OF BERMUDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 500 AM EDT...0900 UTC...THE CENTER OF TROPICAL STORM BERTHA WAS
LOCATED NEAR LATITUDE 33.4 NORTH...LONGITUDE 72.9 WEST. BERTHA IS
MOVING TOWARD THE NORTH-NORTHEAST NEAR 22 MPH...35 KM/H. A TURN
TOWARD THE NORTHEAST WITH INCREASING FORWARD SPEED IS EXPECTED
TO OCCUR LATER TODAY...AND CONTINUE THROUGH WEDNESDAY.  ON THE
FORECAST TRACK...BERTHA WILL PASS ABOUT MIDWAY BETWEEN THE U.S.
EAST COAST AND BERMUDA LATER THIS MORNING.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 65 MPH...100 KM/H...
WITH HIGHER GUSTS...OVER A SMALL AREA NORTHEAST OF THE CENTER.
GRADUAL WEAKENING IS FORECAST DURING THE NEXT 48 HOURS.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 125
MILES...205 KM...PRIMARILY TO THE EAST OF THE CENTER.

THE MINIMUM CENTRAL PRESSURE RECENTLY REPORTED BY AN AIR FORCE

Bertha Track

Now to the Pacific Ocean and the trio of storms there:

Pacific Storms Now

Hurricane Iselle:

SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...15.9N 138.6W
ABOUT 1115 MI...1795 KM E OF HILO HAWAII
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...955 MB...28.20 INCHES

WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE HAWAIIAN ISLANDS SHOULD MONITOR THE PROGRESS OF
ISELLE.  WATCHES MAY BE REQUIRED FOR PORTIONS OF THE ISLANDS BY
TONIGHT OR EARLY WEDNESDAY.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 AM PDT...0900 UTC...THE CENTER OF HURRICANE ISELLE WAS
LOCATED NEAR LATITUDE 15.9 NORTH...LONGITUDE 138.6 WEST. ISELLE IS
MOVING TOWARD THE WEST NEAR 8 MPH...13 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE THIS MORNING.  ISELLE SHOULD TURN
TOWARD THE WEST-NORTHWEST AT A FASTER FORWARD SPEED LATER TODAY AND
WEDNESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 125 MPH...205 KM/H...WITH HIGHER
GUSTS.  ISELLE IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE WIND SCALE.  FURTHER WEAKENING IS FORECAST DURING THE
NEXT COUPLE OF DAYS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 105
MILES...165 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB...28.20 INCHES.

Iselle Path

Tropical Storm Julio:

SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...13.6N 123.7W
ABOUT 1110 MI...1785 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES

WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 AM PDT...0900 UTC...THE CENTER OF TROPICAL STORM JULIO WAS
LOCATED NEAR LATITUDE 13.6 NORTH...LONGITUDE 123.7 WEST. JULIO IS
MOVING TOWARD THE WEST NEAR 15 MPH...24 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH...95 KM/H...WITH HIGHER
GUSTS.  STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS AND
JULIO IS EXPECTED TO BECOME A HURRICANE ON WEDNESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 105 MILES...165 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB...29.53 INCHES.

Julio Path

Disturbance 1:  30% Chance of Cyclone Formation Within 48 hours:

Disturbance 1 Now

1. A small low pressure system is located several hundred miles
south-southeast of Acapulco, Mexico.  Shower and thunderstorm
activity has increased and become more concentrated near the center
of circulation during the past several hours, and  upper-level winds
are expected to gradually improve over the next few days while the
system moves west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...medium...30 percent.
* Formation chance through 5 days...medium...30 percent.

Amazing new photo of Rosetta comet

August 4th, 2014 at 7:59 pm by under Weather

As the ESA’s Rosetta spacecraft closes to within 1000 km of Comet 67P/Churyumov-Gerasimenko, the Rosetta science team has released a new image and made the first temperature measurements of the comet’s core.  The temperature data show that 67P is too hot to be covered in ice and must instead have a dark, dusty crust.

The new image was acquired on August 1st at 02:48 UTC by the OSIRIS Narrow Angle Camera onboard Rosetta at a distance of approximately 1000 km. It shows the rough surface of the double-lobed core in amazing detail.

splash
OSIRIS narrow angle camera view of 67P/C-G from a distance of 1000 km on 1 August 2014. Note that the dark spot is an artefact from the onboard CCD. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Full image and caption

Thermal observations of comet 67P/Churyumov-Gerasimenko were made by Rosetta’s visible, infrared and thermal imaging spectrometer, VIRTIS, between 13 and 21 July, when Rosetta closed in from 14 000 km to the comet to just over 5000 km.

At these distances, the comet covered only a few pixels in the field of view and so it was not possible to determine the temperatures of individual features. But, using the sensor to collect infrared light emitted by the whole comet, scientists determined that its average surface temperature is about -70°C.

Although -70°C may seem rather cold, importantly, it is some 20–30°C warmer than predicted for a comet at that distance covered exclusively in ice.

“This result gives us the first clues on the composition and physical properties of the comet’s surface,” says VIRTIS principal investigator Fabrizio Capaccioni from INAF-IAPS, Rome, Italy.

Other comets such as 1P/Halley are known to have very dark surfaces owing to a covering of dust, and Rosetta’s comet was already known to have a low reflectance from ground-based observations, excluding an entirely ‘clean’ icy surface. The temperature measurements provide direct confirmation that much of 67P’s surface must be dusty, because darker material heats up and emits heat more readily than ice when it is exposed to sunlight.

image
The ESA has prepared a must-see visualization of what sunrise over the comet might look like. Play it

“This doesn’t exclude the presence of patches of relatively clean ice, however, and very soon, VIRTIS will be able to start generating maps showing the temperature of individual features,” adds Dr Capaccioni.

As Rosetta approachs and later orbits the comet, the sensor will study the variation of daily surface temperatures in order to understand how quickly the surface reacts to solar illumination. In turn, this will provide insight into the thermal conductivity, density and porosity of the top tens of centimetres of the surface–important data to help select a target site for Rosetta’s lander, Philae.

It will also measure the changes in temperature as the comet flies closer to the Sun along its orbit, providing substantially more heating of the surface.

“Combined with observations from the other 10 science experiments on Rosetta and those on the lander, VIRTIS will provide a thorough description of the surface physical properties and the gases in the comet’s coma, watching as conditions change on a daily basis and as the comet loops around the Sun over the course of the next year,” says Matt Taylor, ESA’s Rosetta project scientist.

“With only a few days until we arrive at just 100 km distance from the comet, we are excited to start analysing this fascinating little world in more and more detail.”

Credits:

Production editor: Dr. Tony Phillips | Credit: Science@NASA

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander.