HURREVAC QUICK REFERENCE GUIDE
2016 Season Program Version 1.6.2
PART 1: Workspace Layout
1 - Program Header
Tools to manage program setup, update forecast data, print, create a Storm Summary PDF document,
and capture animated (GIF) graphics. The header also includes system messaging capabilities used to
broadcast information from HURREVAC’s technical support staff or the National Hurricane Program
when special situations arise having to do with operation of the software.
2 – Current/Archive Data List
The ‘Current’ tab contains a list of current forecast information, including active storm(s), rainfall
forecast data, river and tide gauge data, weather radar, probabilistic storm surge data, and wind
probability data. The ‘Archives’ tab allows access similar data for historic storms and forecasts.
3 - Map Display/Data Display Window
Displays map and map legend, tropical cyclone advisory text products, tropical weather outlooks by
basin, tabular reports, and charts. Tabs at the top of the window switch between the various views.
4 - Map Tools
Controls what is shown in the Map Display Window (Area 3). Options include map zooming and panning,
measuring distances, moving a storm along a forecast track, changing advisories, and toggling on/off
various STORM FEATURES such as hourly wind ranges, potential track, wind probabilities,
watches/warnings, and more. The bottom two buttons move back and forward through previous map
views, and reset map graphics.
5 - Toolbox
Access to additional STORM FEATURES and MAP ANNOTATION options, BROWSERS for evacuation
clearance times and storm surge maps, and UTILITIES for changing evacuation settings, plus
manipulation and export/import of storm data.
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2016 Season Program Version 1.6.2
PART 2: Map Tools, Context Menu, and Keyboard Shortcuts
A vertical map toolbar and map context menu (accessed by right-clicking on the map) cover the most
commonly-used functions within the Map Display Window (Area 3). Certain buttons and menu items
may be greyed out until a specific data layer is checked on under the Current/Archive Data List (Area 2).
Map Tools
Many buttons have both left and right-click functionality. Hovering over a button will briefly display a
‘tool-tip’ description of its action or actions as shown below.
Zoom (Black Arrow): Draw a box on map with left mouse button to zoom in
Pan (White Hand): Move the map by holding down left mouse button and moving mouse
Measure (Triangle): To measure distance, click left mouse button on map at start/end point
Map Extent (Globe): Toggle between user defined full (left click) and local (right click) map view
Zoom In/Out (Magnifying Glass with + or – symbol): Left click to zoom in/out one level. The current
zoom level, ranging from 5 to 11, is reflected in the bottom right corner of the program window.
Move storm graphics and legend data forward or back within the forecast period for the current
loaded storm and advisory (Yellow Arrows): Left click to move forward/back 1 hour, right click to move
forward/back 6 hours. Bottom button moves storm forward automatically.
Change Advisory (ADV with up/down arrows): These buttons cycle through previous or historic
advisories for the storm you have loaded. Left click to move forward or back 1 advisory. Right click to
move forward or back 3 advisories.
Hourly Forecast: Turn on/off the hourly wind field (Colored Circle) or potential location showing
forecast uncertainty (White Circle). See legend in map display window for more details.
Entire Forecast: Turn on/off 72-hour wind forecast (Colored Swath) or potential track (White Cone) of
area where there is a 66% chance that the center of the storm will pass through during the next 3
(white) or 5 (hollow) days.
Advisory Labels (Text Bubble): Left click for advisory labels on map. Right click for label settings.
Watches/Warnings (Warning Flag): Left Click to add watch/warning graphics to map
Wind Probability Locations (Percent Sign): Show location-based probability labels on map
Back and Forward (Blue Arrow): Left click for previous map extent, then right click for next extent.
Reset (Red Circle): Left click to restore map display to default graphics. Right click to configure defaults.
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Map Context Menu and Keyboard Shortcuts
Right-click within the “Map Display” window to access context menu options for that map location.
Keyboard shortcuts are also available for certain functions noted below as (CTRL-?).
A. Zoom to the extent of the storm of interest (CTRL-Z).
B. Advance the storm into the advisory’s forecast
period. Options are to advance to the hour nearest
the mouse cursor or to input a specific hour.
C. Select a different advisory to display. Options are to
move storm to the advisory nearest the mouse
cursor (CTRL-N), advance to the current/last
advisory, or to input a specific advisory number.
D. Add, move, or delete Custom Text Annotation(s) tied
to a map position nearest the mouse cursor. A
checkbox for MAP ANNOTATIONS > Custom
Annotation within the Toolbox toggles this layer off
and back on.
E. Add (CTRL-W) and remove winds tag(s) that will
display the deterministic forecast wind direction and
speed when overtopped by the storm’s hourly wind
fields. A checkbox for MAP ANNOTATIONS > Wind
Tags within the Toolbox toggles this layer off and
back on.
F. Generate a 72-hour Wind Timing Report for the
specified location on the map. This report gives
deterministic, hour-by-hour forecasted wind detail information for the point location.
G. Generate a Wind Probabilities Report or Graph for the specified location on the map. This report
gives the percent chance of tropical storm, strong tropical storm, and hurricane-force sustained
winds within 6-hour intervals of time throughout a 120-hour forecast period.
H. Creates a 78-hour Surge Probability Report or Graph for the specified location on the map. This
report gives water depth in height above ground level (including tidal fluctuation) that has a 10%
chance of being exceeded and represent values are on the high end of the range of surge depths
that could possibly occur.
I. Add range marks to the map, centered at the location nearest the mouse cursor. The purpose of
range marks is to illustrate how far away the storm is from a location of interest. A checkbox for
MAP ANNOTATIONS > Range Marks within the Toolbox toggles this layer off and back on. Also,
the default range mark interval of 100 statute miles can be modified under SETUP > Default
Map.
J. Adjust the location of Advisory Labels by toggling on and off handles for label dragging (CTRL-L).
An additional menu option is provided for resetting labels back to their original auto-placement.
K. Move the Storm Info Box to a specified location on the map or return it to the legend at the
bottom of the map.
L. Create a Point of Interest at a specified location, with a specific name and type. Additional
options for adding, editing, and importing points of interest are available within SETUP > Points
of Interest.
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2016 Season Program Version 1.6.2
Part 3 – Important Features
Weather Data
Storm Tracks by Ocean Basin – These plots of past and forecast tracks
for storms are derived from details within text-based tropical cyclone
advisories issued by the National Hurricane Center, the Central Pacific
Hurricane Center, and the Joint Typhoon Warning Center. Successive
numbered advisories are published every 6 hours at 0300, 0900,
1500, and 2100 UTC, which is the equivalent of 11 PM, 5 AM, 11 AM,
and 5 PM Eastern Daylight Time or 10 PM, 4 AM, 10 AM, and 4 PM
Central Daylight Time. These are the critical times when you should
check the program for new forecast information. Intermediate(A)
advisories are published in between main advisory times if watches
and warnings are in effect because the storm is close and threatening.
An intermediate advisory only updates the current location and
intensity of the storm and does not contain changes to the forecast
track.
Wind Probabilities – Tropical cyclone wind speed probabilities are
important because they communicate forecast uncertainties not
immediately apparent from the storm tracks and their deterministic
winds projections. The half-degree gridded wind probability product in
HURREVAC is a composite from ALL tropical cyclones in the Northern
Hemisphere. It is updated every 6 hours, approximately 10 minutes
after advisory issuance hour. When this layer is turned on, the map
initially shows areas that have a 5% or greater chance of experiencing
winds over the tropical storm (34kt/39mph) threshold within a 5-day
forecast period. Using radio button options under the Wind
Probabilities heading of the data list, the map display can be changed
to instead show areas with probability of winds over strong tropical storm (50kt/58mph) or
hurricane(64kt/74mph) threshold.
Surge Probabilities – The probabilistic storm surge layer in HURREVAC highlights coastal areas that
have a potential for storm surge flooding. Potential flooding is represented as water height in feet
above ground level and is intended to encompass ‘reasonable worst case scenarios’, meaning that in
only 1 in 10 cases would the water height exceed the value reported at a specified location. The surge
probabilities data source is NHC’s P-Surge 2.5 product (with tide) which will only be produced when a
hurricane or strong tropical storm is within 48 hours of landfall. Updates to this data are tied to the 6hour advisory cycle, but may not be available until 30 minutes or more after issuance hour depending on
the complexity of the storm surge model. Radio buttons under the Surge Probabilities heading of the
data list include options for either a 4-color scale that approximates NHC’s online inundation graphic, or
a more-detailed 20-color scale containing 2-ft intervals of water height.
These surge timing tools appear in the program header only when a
surge probabilities layer is displayed on the map. The first three buttons
(back/forward/animate) are for viewing water heights in 6 hour increments in time. The fourth button in
the row is used to reset the display back to the default 78-hr cumulative surge.
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Doppler Radar Observations – This layer, available only within the CURRENT data list, automatically
updates every 10 minutes with a new snapshot from the network of NEXTRAD stations in the
continental United States. In the context of hurricane tracking, the colors of the radar image provide a
useful illustration of the extent of heavy rainfall and severe thunderstorms for a storm near or over
land.
Rain Forecast – Quantitative precipitation forecasts are useful for anticipating inland flood potential
from a tropical cyclone within 3 days of landfall. The 3-day forecast is issued twice a day at 0000 and
1200 UTC (8 AM and 8 PM Eastern Daylight Time) by the NWS Weather Prediction Center. It is a
generalized precipitation forecast for the continental United States. When this layer is turned on, the
map initially shows a cumulative Day 1 rainfall forecast in the form of isopleths (polygons) of rainfall
amount, with higher amounts of rain nested within lower amounts. Radio button options are available
for cycling the map display through the rainfall forecast for Day 1, Day 2 and Day 3.
Rivers – NOAA’s Advanced Hydrologic Prediction Service (AHPS) is HURREVAC’s source of data for
approximately 1,100 river gauges in hurricane prone states from Texas to Maine, plus Puerto Rico and
Hawaii. Orange, red, and purple colors of river gauge locations on the map indicate where flooding is
either already occurring or forecast to occur within the next 5 days. Clicking on a single gauge location
brings up a plot of water level and access to additional information about flood impacts and history. The
River Flood Outlook highlights general areas within the continental United States that are
experiencing riverine flooding or have the potential for flooding within the next 5 days. Individual river
gauges update continuously, while the Flood Outlook is updated just one time per day typically by 2000
UTC (4 PM Eastern Daylight Time).
Tide Gauges – NOAA Tides Online is HURREVAC’s source of data for approximately 130 tide stations in
hurricane prone states from Texas to Maine, plus Puerto Rico, Hawaii, and U.S. territories in the West
Pacific. Gauge locations are all marked by white circles. Clicking on a single gauge location brings up a
plot of water level predicted by normal tide fluctuations (black line) and observed water level over time
(blue dots). For a storm approaching landfall, the RESIDUAL difference between predicted and
observed tide at nearby tide gauges can be a useful indicator of the storm tide (storm surge + tide)
water level.
Hurricane Evacuation Study Data
Hurricane Evacuation Studies (HES) address hurricane planning and impact assessment for coastal
regions. These studies look at the vulnerability of a population to hurricane threats and provide
guidance to local emergency managers planning an evacuation of the community.
One of the key outputs of an HES process is the matrix of
evacuation clearance times. A clearance time is defined as the
number of hours it takes to move the threatened population to
safety given various factors such as the category of storm, the
tourist occupancy (or population) of the area at the time, and
public responsiveness. HURREVAC utilizes clearance times from
the various HES for its evacuation timing analysis. To see all of the
available evacuation scenarios for your county or parish, go to
BROWSERS > Evacuation Clearance Times within the toolbox.
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Another product of the HES process that is included within HURREVAC is the collection of storm surge
maps of vulnerable coastal regions. Delineated zones on the maps reflect the worst-case surge
inundation possible for each category of hurricane from the Sea, Lake, and Overland Surge from
Hurricanes (SLOSH) model. Map content and format varies with study regions. In addition to surge
zones, some maps include evacuation routes and important assets such as shelters. To view the HES
maps for your county or parish, look under BROWSERS > Storm Surge Maps.
Evacuation Timing
The most crucial function of HURREVAC is its ability to keep the local emergency manager apprised of
how many hours (or days) a community has for preparation and planning in advance of a threatening
storm. As new forecast information becomes available, HURREVAC continually updates and reports on
the community’s ‘Evacuation Start Time’, or last possible time by which an evacuation could be
initiated if it is to be completed before the arrival of the storm hazards based upon planning
assumptions applied in each specific Hurricane Evacuation Study.
HURREVAC arrives at an evacuation start time using input from the official hurricane forecast and the
Hurricane Evacuation Study for the county or parish of interest. To determine the arrival time of tropical
storm force winds, the program takes a worst-case scenario of a direct hit in which the movement speed
and wind fields of the official forecast are retained, but the track is straightened and redirected to the
county of interest. A clearance time is selected from a matrix of times in the local HES based upon storm
intensity and various local factors. Subtracting the number of clearance time hours from the arrival of
the first hazards, we arrive at an earlier point in time…the Evacuation Start Time.
Decisions to mobilize and evacuate communities are not always easy or obvious, and the advantage of
fine-tuning your Evacuation Start Time as well as other storm timeline preparations in HURREVAC is
that you can base decisions upon the closest projections of the storm track, intensity, and size.
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Options exist in the program for
getting alerts with regard to
evacuation start timing and other
storm timelines. To mark evacuation
scenarios for alerting, go to UTILITIES
> Set Evac Options and press the
‘Select Scenarios’ button at the bottom. To add timeline actions and link them to a single county or
parish for alerting purposes, go to Setup > Timeline. Alerting for evacuation scenarios begins only when
within 12 hours (2 advisories) of start time. Alerting for timeline actions can begin as early as 3 days out,
provided that the selected county is within the 72-hour deterministic forecast wind swath.
Reports
Reports are added as new tabs to the end of the display window, either by 1) clicking on the Reports (+)
label shown below and then making an Analysis/Reports selection, or 2) right-clicking on the map and
choosing one of the point-specific reports offered in the map context menu’s items F, G and H.
You must first have a data layer loaded on the map (for instance--a specific storm track and advisory
number, wind probabilities, surge probabilities, or rain forecast) before the corresponding report can be
generated.
Reports have varying geographic scope, as shown here on the left under
the expanded heading for Wind Timing
All Affected Areas – Analysis is done for ALL counties or parishes that are
within the geographic area encompassed by the corresponding map layer.
Information pertaining to each county is in a separate row of the tabular
report.
Local Areas – Report is identical to the one for All Affected Areas, but
includes a shorter list of specific counties or parishes that you have
marked within Setup > Local Areas as locations of interest.
All Affected Points of Interest – Report is similar to the one for All
Affected Areas, except that the analysis is for point locations that you have added or imported into the
program (under Setup > Points of Interest), rather than a larger county-wide area.
Single Area – Analysis is for a SINGLE county or parish only and includes greater detail than can be
gathered from the All or Local Areas reports. Each row of this tabular report represents an increment of
time.
Single Point of Interest – Report is similar in format to the Single Area report, but for a SINGLE point
location. Asking the question “When will winds reach the EOC in the center of the county that I’ve
marked as a point of interest?” gives a different result from asking “When will winds will first reach the
county?”, the latter of which will give an earlier answer based on when the storm’s wind field first
touches an outer edge of the county.
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The following types of analyses give very specific estimates of wind speeds and timing, derived from the
official forecast track. They require only the storm track and a specific advisory to be loaded on the map.
HURREVAC’s archives contain forecast storm tracks dating back from present time to 1995, so these
reports can be generated for any storm.
In contrast, these additional reports below are probabilistic in nature. Only the Error Cone/Potential
Track Area report is derived from the storm track and can be run against any archived storm in
HURREVAC. Wind Probabilities and Surge Probabilities are associated with map data layers populated
only if storm conditions warrant NHC to issue these separate products. A few sample datasets are
provided on the Archives side of HURREVAC under ‘Other Archive Data’ for practice purposes.
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Points of Interest and Other Map Annotations
User-defined Points of Interest (POIs) is a relatively
new feature in HURREVAC. POIs can be used to
supplement or replace the map’s default labeling of
major cities (MAP ANNOTATIONS > Cities). POIs are
also a basis for many kinds of reports in HURREVAC.
Points of Interest must be entered into the program.
To enter a point directly from the map, RIGHT-click on
the location and choose ‘Create Point of Interest Here’
from the map context menu. You will be prompted to
assign a point name and type. The ‘Type’ field is used
for identifying like points such that as a group they
can be toggled on/off, assigned a unique label style,
and filtered in reports. POIs that have been entered into the program are organized according to their
assigned types under MAP ANNOTATIONS > Points of Interest. Use this area of the toolbox to quickly
zoom to the map extent of a specific group of points (by clicking on the text of the Type name) or toggle
off the display of a group (by clicking on the check box of the Type name).
Additional options for adding, editing, and importing POIs are available under SETUP > Points of
Interest. If you have many locations to include in HURREVAC, either 1) batch importing points from a
spreadsheet or 2) externally referencing points stored in a shapefile is recommended. The ‘Points of
Interest Mapping Styles’ button within SETUP gives access to options for assigning specific font styles
and zoom levels for initial appearance to each POI type.
Several other frequently-used map annotation features in HURREVAC include:
Advisory Labels – These text tags appear along the track of
the working storm and can be toggled on/off using STORM
FEATURES > Advisory Labels or the Advisory Label button.
Enter label setup (RIGHT-click to button) to change the type
of information contained in labels, change the interval of
labeling, and font size/style. Individual label positions can be
adjusted by pressing CTRL-L on the keyboard to enable
dragging handles at the beginning of each label. Once the
positions have been adjusted, press CTRL-L again to dismiss
the drag handles and lock the labels in place.
Legend and Storm Information Box – Legend information
appearing across the bottom of the map varies depending on
what data layers are currently displayed. See MAP
ANNOTATIONS > Map Legend for a full list of items that can
appear automatically in the legend, or be omitted if
unchecked. The storm info box (placed by RIGHT-clicking on
the map and choosing ‘Move Storm Info Box Here”) is an
alternative to showing the working storm’s advisory details
on the first several lines of the legend.
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Export Options
Various options exist for getting images,
tabular data, map data, and summary
documents out of HURREVAC for
distribution or analysis in another
program.
Print/Print to File – To capture a static image of HURREVAC’s tracking map in its current state of
appearance, press the Print button and select the ‘Print to Graphics File’ option. PNG is the
recommended file format for best image quality.
Storm Summary PDF – This tool is useful for quickly generating a multi-page document which
summarizes conditions from the currently displayed storm and advisory. The basic summary will include
several paragraphs of information concerning the storm’s intensity and current location, plus a screen
capture from the current map display. The forecast center’s official advisory text products (public
advisory plus forecast discussion) are appended to the end of the summary unless the box for this
option is unchecked. Options are also available to include local information concerning wind and
evacuation timing.
Animated GIF Recording – This feature is used to capture snippets of action from HURREVAC. For
instance, you could record wind ranges advancing along the forecast track of the storm to illustrate the
projected timing of wind hazards and then distribute the resulting animated GIF file. Two buttons within
the program header are needed for GIF recording. The button on the left must first be used to define a
box area of the screen for recording; then the button on the right (or CTRL-R on the keyboard) is used to
start and stop the GIF recording.
Excel Spreadsheet – All tabular reports
in HURREVAC offer the option to save
the data in an XLSX (Microsoft Excel)
spreadsheet format. Right-click to the
individual report’s tab and choose
‘Export Report to Excel’ from the menu.
Shapefile GIS Format – To export map
objects for use in other mapping programs,
go the UTILITIES > Export/Import > Export
to GIS within HURREVAC’s toolbox. Any
storm features, rain isopleths, and flood
polygons currently displayed on the map
will be available for export. Based upon
your selection(s), the program will save the
geographic data in various point, line, and
polygon shapefiles with attributes
associated with each shape.
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2016 Season Program Version 1.6.2
PART 4: Answering Key Questions When a Storm is Approaching
Gulf Coast Scenario
The following practice scenario is based on tracking of Hurricane Isaac, a storm which impacted the U.S.
Gulf Coast in 2012. To answer these first three sets of questions, check on ‘Isaac’ from within 2012
Storms > Atlantic of the ARCHIVES data list. Within the Toolbox, uncheck STORM FEATURES > Actual
Track Ahead and go to Advisory 25 using either the (ADV >) button or the map context menu’s ‘Select
Advisory’ option. The first three questions demonstrate the use of probabilistic tools and resources
while the storm is still distant and forecast uncertainty is high.
1. What coastal states are within the potential track of the storm center and/or the potential area for
tropical storm force or greater winds? How early might tropical storm force winds begin in
Louisiana?
Right-click on the (Potential Track Area) button to add a hatched fringe winds area surrounding the
white cone that represents where the center of the storm is most likely to track within the next 3
days. The states of Florida, Alabama, Mississippi, Louisiana, and Texas are within the potential
area of impact.
RIGHT-click on the Potential Location button (or within the Toolbox, turn on ‘Potential Location +
Winds’) and advance the storm along the forecast track using the yellow ‘Move Storm Ahead’ (arrow
+) button. Stop when the hatched ring first touches the Louisiana coast and note the date and time
from the legend. Winds may start in Plaquemines Parish, LA as early as 5 PM on August 27th.
2. How have coastal watches and warnings changed from Advisory 24 to Advisory 25? What is NHC’s
rational for these changes?
Within the Toolbox, ensure that STORM FEATURES > Watches/Warnings is checked. Use the ADV >
and < ADV buttons to toggle back and forth between the two advisories and note the differences in
highlighted coastal areas. A watch means that the threat is possible within 48 hours and a warning
means that the threat is possible within 36 hours.
The following line appears in the legend to indicate watch and warning colors:
Gulf Coast Scenario
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With Advisory 25 showing on the map, click on the
Advisory tab and scroll down to read the contents
of the Public Advisory & Discussion. The top of the
public advisory specifically describes changes to
the watch/warning areas. The bottom of the
discussion explains the rational for changes.
Tropical storm warnings have been added to both
the East Coast and Panhandle of Florida due to an
increase in size of Isaac’s wind field. The western
portion of Louisiana’s coast also has new watches
and warnings due to a westward shift in the
forecast track from the previous advisory.
3. For Orleans Parish, LA, which time period has the earliest chance for onset of tropical storm force
winds? What is the overall (cumulative) chance of hurricane force winds and when are hurricane
force winds most likely to begin?
Load the Isaac25.tpcprblty.2012082706.zip file from within Other Archived Data > Wind Probabilities
of the ARCHIVES data list. This file contains wind probabilities for the entire northern hemisphere at
the time of Isaac Advisory 25 and must be loaded separately from the Isaac storm track before the
above questions can be answered. In a live storm event, the corresponding wind probability graphic
would be accessed from the CURRENT data list, under the Wind Probabilities heading.
Click on the Reports(+) tab and add a Wind Probabilities > Single Area report for Orleans Parish,
Louisiana. The individual time period that has the earliest chance for onset of tropical storm force
winds is from 1 to 7 PM Monday (highlighted in blue as a 9% chance). The overall chance of
hurricane force winds is 28% and the most likely onset for these winds is from 1 to 7 PM Tuesday
(highlighted in red as a 12% chance).
Gulf Coast Scenario
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Each of the next two Isaac advisories (#26 and #27) contains a forecast track very similar to that of
Advisory 25. With forecast certainty improving and the storm 24 to 48 hours of landfall, deterministic
wind timing and intensity reports should be used to supplement probabilistic data within HURREVAC.
Advance to Isaac Advisory 26 using the (ADV >) button before answering the next three questions.
4. What county or parish has the highest forecasted peak wind? What are the specific hour-by-hour
wind projections for this area?
Click on the Reports(+) tab and select Wind Timing Chart > All Affected Areas to see wind timing and
intensity for all counties within the forecast wind swath. The information is generalized with each
column representing a 2-hour block of time that is colored according to projected wind threshold
exceedance: tropical storm(blue), strong tropical storm(yellow), and hurricane force(red). Use the
button at the bottom of the report to sort by ‘Strongest’. Plaquemines Parish, Louisiana is
projected to experience the earliest, strongest, and longest duration of winds.
Add an additional report for Wind Timing > Single Area and select Plaquemines Parish, Louisiana.
The ‘Date/Time’ and ‘Wind Speed’ columns provide the wind speed that is projected for each hour
in the forecast period. Do not focus on specific wind speeds reported here, but instead consider this
a general guide of possible timing and severity.
Gulf Coast Scenario
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5. For areas within the potential track of Isaac, how soon would evacuations need to begin if using
HURREVAC’s default settings for evacuation options?
Click on the Reports(+) tab and select Evacuation Timing > All Affected Area Scenarios. Use the
button at the bottom of the report to filter by ‘In Error Cone’. Most evacuations (if warranted)
would need to begin very soon and before the next advisory cycle.
Add an additional report for Evacuation Timing > Single Area Scenario and choose Plaquemines’ Fast
Storm/Off Peak scenario. By default, this will utilize a clearance time of 7 hours based on a
Category 1 storm under medium tourist occupancy and medium response.
For both of the above reports, HURREVAC uses a worst-case direct hit approach for calculating wind
arrival. Default selection of SS Category is based upon the highest category forecast over the entire
storm track.
Gulf Coast Scenario
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6. How can the default settings that HURREVAC uses to calculate evacuation start times be modified?
How many different evacuation scenarios exist in the Hurricane Evacuation Study for Plaquemines
Parish and what is their range of clearance times?
Click on the ‘Evac Options’ at the bottom of the report, or select UTILITIES > Evacuation Options
from within the Toolbox for viewing and changing settings. Change the Tourist Occupancy to ‘High’
and the Response to ‘Slow’, press ‘Apply to ALL’, then OK to dismiss the screen. Return to the ‘Evac
Timing (Plaquemines, LA)’ report and press ‘Refresh’ in the bottom right corner. A 10-hour
clearance time is now in effect and the EVAC START TIME is reported as an earlier 10 AM CDT.
To review all clearance time scenarios for a county or parish, go to BROWSERS > Evacuation
Clearance Times. Choose Louisiana and Plaquemines. Plaquemines Parish has 4 evacuation
scenarios with clearance times ranging from 5 to 50 hours.
Gulf Coast Scenario
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Storm surge and inland flooding potential should also be evaluated once the storm is close and
threatening. Advance to Isaac Advisory 29, then to Isaac Advisory 32 to get an idea of the storm’s
location in relation to the rain, river, and tide data to be considered in this last portion of the scenario.
In a live storm event, this data would be accessed from the CURRENT data list under ‘Rain Forecast’,
‘Rivers’, or ‘Tide Gauges’. You may wish to turn off many of Isaac’s STORM FEATURES for a less cluttered
view of the following map layers.
7. What areas are forecast to receive 9 inches or more of rain from Isaac?
Load the Isaac29.082812z_2012.qpf file from within Other Archived Data > Rain Forecast of the
ARCHIVES data list. This file contains a three-day quantitative precipitation forecast for the
continental US at the time of Isaac Advisory 29 and must be loaded separately from the Isaac storm
track before the above question can be answered. Click on the Reports(+) tab and add a Rain/River >
Rainfall for All Affected Areas report and sort by the last column which provides totals from all three
days. Terrebonne Parish in Louisiana, Baldwin and Mobile Counties in Alabama are all forecast to
receive 9 inches or more of rain.
8. What river gauge locations near the track of Isaac are forecast to reach minor, moderate, or major
flood stage within the next few days?
Load the Isaac32.0828_2012.riv file from within Other Archived Data > River Gauges of the
ARCHIVES data list. This file contains river level data from the time of Isaac Advisory 32 when the
storm was near landfall and must be loaded separately from the Isaac storm track before the above
question can be answered. A number of gauges near the coast of Mississippi, and the LA/MS
border, especially to the right of the storm track are forecast to reach flood stage within 24 hours.
Click on any one individual gauge to view a chart of water level as well as descriptions of flood
conditions/history from the USGS.
Gulf Coast Scenario
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9. What effect is storm surge having on water levels at coastal tide gauges near the track of Isaac?
Load the Isaac32.0828_2012.tid file from within Other Archived Data > Tide Gauges of the ARCHIVES
data list. This file contains tidal water level data from the time of Isaac Advisory 32 when the storm
was near landfall and must be loaded separately from the Isaac storm track before the above
question can be answered. White circles appear along the coast to represent tide gauge locations.
Click on the Pilots Station SW Pass gauge on the southeastern end of Plaquemines Parish, LA.
At 8 PM CDT on 8/28, the difference between observed tide height (blue dots) and predicted
astronomical tide (black line) was 3.34ft. The storm’s closest approach to this gauge location
occurred 2 hours earlier (red vertical line), so storm surge is likely at its peak and would not be
expected to get much worse. On the other hand, the actual water height may still continue to rise
slightly due to the coming of the next high tide at 8 AM CDT on 8/29.
NOTE: During a live storm within 48 hours of landfall, the Surge Probabilities layer will offer a
broader geographic look at possible storm surge effects. To see application of a sample surge
probabilities dataset, refer to question 10 of the Northeast Atlantic Coast scenario involving
Hurricane Sandy (page 25 of this guide).
Gulf Coast Scenario
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PART 4: Answering Key Questions When a Storm is Approaching
Northeast Coast Scenario
The following practice scenario is based on tracking of Hurricane Sandy, a storm which impacted the U.S.
Northeast Atlantic Coast in 2012. To answer these first three sets of questions, check on ‘Sandy’ from
within 2012 Storms > Atlantic of the ARCHIVES data list. Within the Toolbox, uncheck STORM FEATURES
> Actual Track Ahead and go to Advisory 23 using either the (ADV >) button or the map context menu’s
‘Select Advisory’ option. The first two questions demonstrate the use of probabilistic tools and resources
while the storm is still distant and forecast uncertainty is high.
1. What coastal states are within the potential track of the storm center and/or the potential area for
tropical storm force + winds? How soon might the storm center make landfall and where?
RIGHT-click on the (Potential Track Area) button to add a hatched fringe winds area surrounding the
white cone that represents where the center of the storm is most likely to track within the next 3
days. Due to an unusually large wind field, at least a dozen coastal states from South Carolina to
Maine are in the potential area of impact.
LEFT-click on the Potential Location button (or within the Toolbox, turn on ‘Potential Location’) and
advance the storm along the forecast track using the yellow ‘Move Storm Ahead’ (arrow +) button.
Stop when the white circle first touches the coast and note the date and time from the legend. The
storm center could potentially make landfall as early as late Monday night, anywhere from
northern Maryland to Long Island.
2.
For Nassau County, NY which time period has the earliest chance for onset of tropical storm force
winds? What is the overall (cumulative) chance of hurricane force winds and when are hurricane
force winds most likely to begin?
Load the Sandy23.tpcprblty.2012102800.zip file from within Other Archived Data > Wind
Probabilities of the ARCHIVES data list. This file contains wind probabilities for the entire northern
hemisphere at the time of Sandy Advisory 23 and must be loaded separately from the Sandy storm
track before the above questions can be answered. In a live storm event, the corresponding wind
probability graphic would be accessed from the CURRENT data list, under the Wind Probabilities
heading. Click on the Reports(+) tab and add a Wind Probabilities > Single Area report for Nassau,
New York. The individual time period that has the earliest chance for onset of tropical storm force
winds is from 2 to 8 AM Monday (highlighted in blue as a 6% chance). The overall chance of
hurricane force winds is 10% and the most likely onset for these winds is from 8 PM to 2 AM
Tuesday (highlighted in red as a 4% chance).
Northeast Coast Scenario
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Each of the next two Sandy advisories (#24 and #25) contains a forecast track very similar to that of
Advisory 23. With forecast certainty improving and the storm 24 to 48 hours of landfall, deterministic
wind timing and intensity reports should be used to supplement probabilistic data within HURREVAC.
Advance to Sandy Advisory 24 using the (ADV >) button before answering the next three questions.
3. What county has the highest forecasted peak wind? What are the specific hour-by-hour wind
projections for this area?
Click on the Reports(+) tab and select Wind Timing Chart > All Affected Areas to see wind timing and
intensity for all counties within the forecast wind swath. The information is generalized with each
column representing a 2-hour block of time that is colored according to projected wind threshold
exceedance: tropical storm(blue), strong tropical storm(yellow), and hurricane force(red). Use the
button at the bottom of the report to sort by ‘Strongest’. Ocean County, New Jersey is projected to
experience the earliest, strongest, and longest duration of winds.
Northeast Coast Scenario
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Add an additional report for Wind Timing > Single Area and select Ocean County, New Jersey The
‘Date/Time’ and ‘Wind Speed’ columns provide the wind speed that is projected for each hour in the
forecast period. Do not focus on specific wind speeds reported here, but instead consider this a
general guide of possible timing and severity.
4. For New Jersey counties within the potential track of Sandy, when would evacuations have needed to
begin if using HURREVAC’s default settings for evacuation options?
Go to SETUP > Local Areas and mark all of New Jersey’s counties as areas of interest. Next click on
the Reports(+) tab and select Evacuation Timing > Local Area Scenarios. Evacuations (if warranted)
of certain NJ counties with longer clearance times should have begun no later than the evening
before this advisory. The others in this list would need to begin very soon and before the next
advisory cycle.
Northeast Coast Scenario
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Add an additional report for Evacuation Timing > Single Area Scenario and choose Middlesex
County’s ‘Standard’ scenario. By default, this will utilize a clearance time of 8 hours based on a
Category 1 storm under medium tourist occupancy and medium response.
For both of the above reports, HURREVAC uses a worst-case direct hit approach for calculating wind
arrival. Default selection of SS Category is based upon the highest category forecast over the entire
storm track.
5. How can the default settings that HURREVAC uses to calculate evacuation start times be modified?
How many different evacuation scenarios exist in the Hurricane Evacuation Study for Middlesex
County and what is their range of clearance times?
Click on the ‘Evac Options’ at the bottom of the report, or select UTILITIES > Evacuation Options
from within the Toolbox for viewing and changing settings. Change the Tourist Occupancy to ‘High’,
press ‘Apply to ALL’, then OK to dismiss the screen. Return to the ‘Evac Timing (Middlesex, NJ)’
report and press ‘Refresh’ in the bottom right corner. A 10-hour clearance time is now in effect and
the EVAC START TIME is reported as an earlier 7 AM EDT.
Northeast Coast Scenario
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To review all clearance time scenarios for a county or parish, go to BROWSERS > Evacuation
Clearance Times. Choose New Jersey and Middlesex. Middlesex County has just one ‘Standard’
evacuation scenario with clearance times ranging from approximately 4 to 20 hours.
Northeast Coast Scenario
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Storm surge and inland flooding potential should also be evaluated once the storm is close and
threatening. Advance to Sandy Advisory 29 to get an idea of the storm’s location in relation to the rain,
river, and tide data to be considered in this last portion of the scenario. In a live storm event, this data
would be accessed from the CURRENT data list under ‘Rain Forecast’, ‘Rivers’, or ‘Tide Gauges’. You may
wish to turn off many of Sandy’s STORM FEATURES for a less cluttered view of the following map layers.
6. What areas are forecast to receive 6 inches or more of rain from Sandy?
Load the Sandy29.102912z_2012.qpf file from within Other Archived Data > Rain Forecast of the
ARCHIVES data list. This file contains a three-day quantitative precipitation forecast for the
continental US at the time of Sandy Advisory 29 and must be loaded separately from the Sandy
storm track before the above question can be answered. Click on the Reports(+) tab and add a
Rain/River > Rainfall for All Affected Areas report and sort by the last column which provides totals
from all three days. A number of counties in Pennsylvania, Maryland, and West Virginia are
forecast to receive 6 inches or more of rain.
7. What river gauge locations near the track of Sandy are forecast to reach minor, moderate, or major
flood stage within the next few days?
Load the Sandy29.1029_2012.riv file from within Other Archived Data > River Gauges of the
ARCHIVES data list. This file contains river level data from around the time of Sandy’s landfall and
must be loaded separately from the Sandy storm track before the above question can be answered.
A number of gauges near the forecast track of Sandy, especially in Maryland and Pennsylvania are
at or approaching flood stage. Click on any one individual gauge to view a chart of water level as
well as descriptions of flood conditions/history from the USGS.
Northeast Coast Scenario
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8. What effect is storm surge having on water levels at coastal tide gauges near the track of Sandy?
Load the Sandy29.1029_2012.tid file from within Other Archived Data > Tide Gauges of the
ARCHIVES data list. This file contains tidal water level data from around the time of Sandy’s landfall
and must be loaded separately from the Isaac storm track before the above question can be
answered. White circles appear along the coast to represent tide gauge locations.
Click on the Sandy Hook NJ
gauge on the northeastern
tip of New Jersey.
At 8 PM EDT on 10/20, the
difference between
observed tide height (blue
dots) and predicted
astronomical tide (black
line) was 7.85ft.
9. How does this observed surge value from the time of Sandy compare to the Maximum of Maximums
(MOM) for all hypothetical Cat 1 storms that were modeled with the SLOSH program?
Under SLOSH Options, choose PLANNING and then use the drop down box to select ‘Cat 1 MOM’.
The maximum surge from the model appears in red text on the left side of the chart and as grey
lines added to the top of predicted surge.
Surge of 7.5 ft is the worstcase CAT1 modeled by
SLOSH. Hurricane Sandy,
with its extremely large
wind field, actually had
observed surge slightly
higher than what was
modeled.
Northeast Coast Scenario
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10. What is the potential for storm surge flooding for the coastal regions within the forecasted path of
Hurricane Sandy? Looking specifically at Sandy Hook, NJ, how high could the water get above ground
level and what is the most likely time frame for peak flooding?
Load the Sandy27.psurge.2012102900.zip file from within Other Archived Data > Surge Probabilities
of the ARCHIVES data list. This file contains probabilistic surge modeling corresponding to Sandy
Advisory 27 and must be loaded separately from the Sandy storm track before the above questions
can be answered. Zoom into the New York and New Jersey area to see colored squares representing
average water height over 625 x 625-meter grid cells. The data shown represents a ‘reasonable
worst case scenario’ of water height that has just a 1 in 10 chance of being exceeded within the next
78 hours.
Red and orange areas
along the coast will be
particularly vulnerable
to storm surge
inundation from Sandy.
Use the Surge Timing
tools to advance
through the 6 hour
increments of time for
surge and note from the
legend the periods when
surge is expected to be
worst in these areas of
concern.
most likely to occur is from 8 PM Monday to 2 AM Tuesday.
Northeast Coast Scenario
For specific information
about the Sandy Hook
location, right-click on
the area noted in the
graphic and generated a
report for ‘Surge
Probabilities this
Location’. The
cumulative ‘reasonable
worst case scenario’
storm surge value
reported for this location
is 10 ft and the
incremental time period
in which a peak surge is
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