).I love the cone the NHC uses (I think just about everyone does, it grows on you once you've dealt with it for so long), but it leaves many things out.
1. The cone shows where they think the center will be 66% of the time over the course of 72 to 120 hours. This is all great and dandy, but a hurricane is not a point. We need something that shows where the impacts are expected...not where the center is expected.
2. The cone does not show how bad possible impacts will be. The public would be better prepared with a graphic showing where the worst is expected, and what hazards will provide the most impact, in my opinion.
3. Other than where the center is going, through the cone, there generally is not a lot of focus on expected inland impacts. You hear about the hurricane warnings on the coast, but those winds don't just stop at the beaches, they continue producing damage well inland (sometimes more damage well inland than on the immediate coast!). There is also rain, surge, etc. While this is generally covered by local NWS offices, and broadly touched by the NHC, it seems you don't hear a lot about it until the storm is poised to make landfall (versus giving people a long heads up, like the coast gets).
This graphic was an attempt to mitigate those discrepancies. If the NHC were to create the graphic, it would be mostly a "broad brush" approach, with maybe regional differences (i.e. gulf coast, south east and north east segments). If these were issued by local NWS offices, perhaps as a supplement to hurricane local statements, they could be much better tailored to local differences in impacts. The graphics could be issued by both, but would require a bit of coordination between groups. I'm not here to debate that, though. I'm more interested in how this would impact people's prepping levels and knowledge about potential impacts.
NOTE: The description, posted below, is meant as a rough draft. The wind levels and surge levels can be modified as needed (regional vulnerabilities). This does not include tornadoes into the risk assessment. Perhaps at a later date they can be added, once we can better predict whether a TC will produce 0, 5, or 100 of them. Another thing I'd like to add, is what are the reasons for the color level? Are they in an orange for wind, surge, rain, all of them, etc. That way people know more about the hazards facing them. Something similar to an AFD (or the forecast discussion) could, potentially, be posted with the graphic, giving the reasons why the forecaster chose orange or red.
Here is the graphic, originally posted on June 6, at 1:07 am:
I used the TS wind graphic product for the colors (as this was a rough draft), and did 3 time frames, to help "map out" the lines.
Orange
I used the 36 hr TS wind map, using the 20% line:
http://img826.imageshack.us/img826/558/36hrtsmap.gif
Yellow
I used the 60 hr TS wind map, using the 20% line extending off of the Orange:
http://img12.imageshack.us/img12/8682/60hrtsmap.gif
Blue
I used the 120 hr TS wind map, and I used the outside of the colors as the basis:
http://img832.imageshack.us/img832/2912/120hrtsmap.gif
Here are the "Awareness Level" meanings (roughly, for a beginning):
Greater than 36 hours out
Green:
All clear, no threats expected in the next 120 hours.
Blue:
Possible impacts from a tropical cyclone within the next 120 hours, residents should monitor the latest information and start checking their supplies. Cities should prepare for potential emergency operations. (For this, an area could be highlighted, and this does NOT match the cone! This is for all potential impacts)
Amber/Yellow:
Impacts from a tropical cyclone are possible starting within the next 60 hours, residents should continue to monitor the latest information and prepare for adverse weather conditions. Cities should activate their emergency operations groups, if they have not done so already. Evacuation considerations should be made in accordance to local operating procedures.
Less than 36 hours out
Orange:
Minor to moderate impacts from a tropical cyclone are likely, starting within the next 24 to 36 hours. Residents should continue to monitor the latest information and rush to completion any preparations. Potential impacts include sporadic power outages (generally only a day or two for outages to be restored), minor to moderate wind or surge damage, and potential for minor to moderate inland flooding. Residents in these locations should be prepared for a possibility of an upgrade to Red if the storm changes course or if conditions appear they will be worse than currently forecast. Winds will generally be in the 35 to 75 mph range, with surge in the 1 to 7 ft range.
Red:
Severe impacts from a tropical cyclone are likely, starting within the next 24 to 36 hours. Residents should continue to monitor the latest information and rush to completion any preparations. Impacts include, but are not limited to, long duration power outages (1 to 2 weeks or more), significant wind or surge damage, including complete destruction of some structures, and potential for moderate to major inland flooding. Evacuations should be underway and nearing completion, as severe impacts are expected in less than 24 hours. Residents within this area may be on their own for survival, and survival may be difficult to near impossible within some areas. Winds will generally be in the 75 to 115 mph range, with storm surge in the 7 to 15 ft range.
Black:
Extremely dangerous and life threatening weather conditions are imminent (within 12 to 24 hours) or ongoing, and potentially include high winds, large storm surge, etc. Impacts include, but are not limited to, long term power outages (greater than 2 weeks), complete destruction of houses or buildings are possible in many areas due to winds or surge, and potential for major to record inland flooding. Residents within this area will be on their own for survival until after the storm passes, and survival will be difficult to near impossible within most areas. Winds will generally be in the 115 to 170 mph range, with storm surge in the 15 to 25+ ft range.