Paper on the resistance of hurricanes to wind shear released online in the Journal of the Atmospheric Sciences

Vertical wind shear, the difference of wind velocity between the ground and the top of the tropical cyclone, generally restricts tropical cyclone intensification. A tropical cyclone can become tilted by the wind shear so that that the circulation at the top is displaced from that near the ground. Sometimes the tropical cyclone is able to again become upright and intensify, but often such tilting is the beginning of the storm’s demise. A simple mathematical model predicts how much tilt the tropical cyclone will have based on how much cloudiness is within the eyewall as well as the structure of the wind outside the eyewall. This paper clarifies basic ways that a tropical cyclone can resist wind shear.

Important Conclusions:

Tropical cyclones are better able to stay upright in vertical wind shear when there are lots of clouds in the eyewall.

Tropical cyclones are better able to stay upright in vertical wind shear when the wind’s spin quickly decays away from the eyewall.

A simple mathematical model confirms these findings.

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There paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-14-0318.1.

Paper on the relative roles of the ocean and atmosphere in maintaining hurricanes published in Monthly Weather Review

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Summary:

Until now, it was believed that hurricanes are maintained by the ocean alone.  Observations from 62 hurricanes during 32 years support a different, nuanced conclusion.  Besides the ocean, near-surface air temperature and moisture play a large, often dominant, role in maintaining a hurricane.

Important conclusions:

1.  The long-held belief that an ocean surface temperature of at least 26 degrees C (80 degrees F) is required to maintain a hurricane was not supported in 6% of the cases studied.  Atmospheric moisture conditions in areas of high wind speeds are what cause the “80-degree F threshold” for hurricanes.

2.  For hurricanes within 29 degrees of the equator, the atmosphere, not the ocean, was found to be the most important factor in maintaining the hurricane.

The full paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-13-00380.1.

2015 Hurricane Field Program/Intensity Forecast EXperiment (HFP/IFEX) Planning Meeting

On Tuesday, May 19, 2015, Dr. Robert Rogers led a kick off meeting to discuss our flight experiments and modules that will be part of the 2015 hurricane field campaign. Click here to review the proposed experiments.

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HRD seminar – Dave Jones (Storm Center Communications) and Svetla Hristova-Veleva (NASA/JPL) – 13 May 2015

Dave Jones and Svetla Hristova-Veleva provided an overview of the Tropical Cyclone Information System (TCIS) developed at NASA Jet Propulsion Laboratory (JPL) to facilitate the inter-comparison of hurricane model simulations and passive microwave satellite observations within a common geo-referenced and web-based application. The purpose of their visit was to engage operational hurricane forecasters and researchers in providing:

  • Useful input & feedback into the capabilities of TCIS;
  • Identify strengths and weaknesses; and
  • Identify modifications that will better serve NHC & HRD

The intent of the feedback session is to enable JPL and StormCenter Communications to modify TCIS to better serve the needs of the hurricane research and operational communities. Dave provided an overview of StormCenter Communications role in improving access to TCIS and Svetla summarized TCIS and gave numerous examples of TCIS products and analysis tools. Copies of their presentations are available in a zip archive on the ftp site at:

ftp://ftp.aoml.noaa.gov/hrd/pub/blog/seminars/2015/TCIS_discussion.zip

You’re invited to the NOAA Open House, Saturday, 16 May, 10am-3pm

2015_openhouseNOAA’s National Marine Fisheries Service/ Southeast Fisheries Science Center and the Atlantic Oceanographic and Meteorological Laboratory, in collaboration with the University of Miami Rosensteil school and Miami-Dade County Public Schools, are hosting an open house on Saturday, 16 May, from 10am to 3pm.  Participants will learn about a variety of scientific topics including hurricane research, climate science, oceanography, local fisheries, coral communities, and endangered species.  NOAA scientists will be there to describe their research projects and answer questions.

The open house will be an interactive experience, with participants visiting:

1.  NOAA’s National Marine Fisheries Service Southeast Fisheries Science Center.  The center does research into

  • fishery resource conservation
  • fishery development and utilization
  • habitat conservation
  • protection of marine mammals and endangered marine speciesmiami

2.  NOAA’s Atlantic Oceanographic and Meteorological Laboratory.  The laboratory does research into

  • hurricanes
  • coastal ecosystems
  • oceans and human health
  • climate
  • ocean acidification
  • ocean observationsSONY DSC

3.  The University of Miami Rosensteil School’s Experimental Hatchery where research into local fisheries and replenishment are done.  hatchhead

4.  The MAST Academy (Maritime & Science Technology High School of Miami-Dade County Public Schools) will have two mobile facilities geared toward middle school students.

a.  The Land SHARC (Science Hands-On And Related Careers) will show students about careers and opportunities in marine biology and physical oceanography.

b.  The Weather on Wheels will show them about careers and opportunities in weather and climate.Screen Shot 2015-05-11 at 2.25.33 PM

A visit to all four facilities will take about 3-4 hours.  Visitors must present a valid government issued ID (driver’s license or passport) to access the NOAA facilities.

We hope to see you there!

For more information, please contact:

Erica Rule at (305) 361-4541 (Email: Erica.Rule@noaa.gov)

or Essie Coleman-Duffie at (305) 361-4237 (Email: Essie.C.Duffie@noaa.gov)

Paper examining the region closest to the ocean surface in hurricanes and typhoons released online in the Journal of Geophysical Research

Global Positioning System dropwindsondes are released by Hurricane Hunter Aircraft to measure temperature, pressure, humidity, and wind speeds. Dropwindsonde data show what the wind, temperature and moisture are like nearest the ocean surface. In this study, hurricanes in the Atlantic Ocean are compared with typhoons in the Pacific Ocean.

Important Conclusions:

1. The atmospheric region nearest the ocean surface is generally similar in typhoons and hurricanes.
2. This region in typhoons tends to be warmer and moister than that in hurricanes.
3. This helps us understand and forecast the way that heat and moisture from the ocean drives tropical cyclones.

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The paper can be accessed at http://onlinelibrary.wiley.com/doi/10.1002/2014JD022640/full.

Paper on improvements to hurricane forecasts using data nearest the ocean surface released online in Monthly Weather Review

The National Hurricane Center uses the Hurricane Weather Research and Forecasting (HWRF) model to forecast where a hurricane will go, how strong it will be, how large it will be, and where the strongest winds are. This paper looks at changes in what is happening in the atmosphere closest to the ocean surface and how that can change these forecasts. NOAA Hurricane Hunter aircraft observations are compared to the HWRF forecasts. When differences between the model and the observations are found, the model is changed to greatly improve the forecasts. This technique can be used to make future versions of the model even better.

Important conclusions:

1. The differences between HWRF and NOAA Hurricane Hunter aircraft observations have been used to upgrade the model.

2. These upgrades led to large improvements in forecasts of where the hurricane will go and how strong it will be.

3. This technique can be used to make future forecast models even better.

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The paper can be accessed at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-14-00339.1.

HRD Monthly Science Meeting of May 2015

May’s science meeting consisted of 6 presentations:

  1. Eric Uhlhorn– Validation of Coyote Low-level UAS Observations In Hurricane Edouard
  2. Rob RogersMultiscale kinematic structure and evolution of Hurricane Edouard from 14-16 September using Global Hawk dropsondes and P-3 airborne Doppler radar
  3. Paul Reasor – Research Evaluation of the G-IV Tail Doppler Radar
  4. Sim Aberson – G-IV TDR observation quality as measured by HEDAS
  5. Stan Goldenberg – Temporally Homogeneous Verifications of Intensity & Track
  6. Hua Chen – VORTEX SE and Hurricane Landfalling Tornadoes

All the presentations and posters are available on the anonymous ftp site at:

ftp://ftp.aoml.noaa.gov/hrd/pub/blog/meetings/2015/science/HRD_SciMeet_20150514.zip