1. Title
Submitter
Informational Item: Maintaining 3-hourly Intermediate Public Advisory Cycle
RSMC Miami
Date Submitted
April 2015
Discussion
The current guidelines state that RSMC Miami will issue public advisories (TCPs) at 2-hourly
intervals whenever coastal tropical cyclone watches / warnings are in effect and coastal radars are
able to provide reliable hourly center position estimates. When RSMC Miami is issuing TCPs on
2-hourly cycles, hourly position estimates are issued (on the hour between TCP issuance) in the
Tropical Cyclone Update (TCU; prior to 2013, the Tropical Cyclone Position Estimate was issued
in these cases) to provide a continuous flow of information regarding the center location of a
tropical cyclone when the center can be easily track with land-based radar. Although RSMC Miami
typically mentions in the Tropical Cyclone Discussion and indicates in the TCP when 2- versus 3hourly advisories will be issued, the less frequently used 2-hourly advisory cycle sometimes creates
confusion among our core partners.
This agenda item proposes that RSMC always remain on a 3-hourly TCP cycle whenever watches /
warnings are in effect or a tropical cyclone is over land at tropical storm strength or greater. The
elimination of the 2-hourly TCP cycle would preserve the issuance of public advisories at standard
times during an event whenever watches or warnings are in effect. This change would also keep the
issuance of public advisories out of the interval when RSMC forecasters are preparing the next
forecast (e.g., the 9 a.m. intermediate advisory “B” must be prepared and sent while the 11 a.m.
forecast is being developed). Maintaining public advisories on a 3-hour cycle will alleviate
workflow issues while the new track and intensity forecast is being prepared and wind and surge
watches / warnings are being collaborated.
This change would not affect the hourly flow of key storm information from RSMC, as we would
continue to issue TCUs at hourly intervals whenever coastal watches / warnings are in effect and
the center can be easily tracked with land-based radar. TCUs contain all the key storm parameters,
and allow the inclusion of additional statements of interest, as appropriate, but are easier to prepare
and disseminate than an intermediate TCP.
This change is expected to have little or no change on how warnings could be issued or
discontinued. International watches and warnings could be updated through any Public Advisory or
TCU. U.S. watches and warnings could be discontinued through a Public Advisory or TCU. U.S.
watches and warnings must still be issued with a full advisory package or a Special Advisory.
The proposed advisory cycle for storms meeting the watch / warning and center-tracking
requirement would be:
5:00 AM EDT (0900 UTC)
Full advisory package including Public Advisory
6:00 AM EDT (1000 UTC)
TCU (providing an hourly position update, summary block of
key storm information, and other key observations deemed appropriate)
7:00 AM EDT (1100 UTC)
TCU
8:00 AM EDT (1200 UTC)
Intermediate Public Advisory
9:00 AM EDT (1300 UTC)
TCU
10:00 AM EDT (1400 UTC)
TCU
11:00 AM EDT (1500 UTC)
Next full advisory package
RECOMMENDATIONS: Eliminate 2-hourly intermediate advisories. Maintain 3-hourly public
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Action
advisory cycle whenever coastal watches or warnings are in effect or a tropical cyclone is over land
at tropical storm strength or greater. When coastal watches or warnings are in effect and the center
can be easily tracked with land-based radar, RSMC Miami would issue hourly TCUs in between 3hourly Public Advisories to provide a continuous flow of information regarding the center location
of a tropical cyclone. These TCUs would contain a summary block of key storm information, and
other key observations as deemed appropriate.
Provide appropriate public notices.
Item ACTION: Recommendations accepted. Forward to WMO RA-IV.
2. Title:
Name Replacement
Submitter:
RSMC Miami
Date Submitted:
April 2015
Discussion:
Given the relevance of the name Isis in the world current affairs, RSMC Miami recommends the
replacement of the name Isis from the 2016 Eastern North Pacific list by Ilene, Iola or Ivette.
Action
Forward to WMO RA-IV HC Committee for consideration.
3. Title
Informational Item: Change Time Zones for Eastern Pacific Tropical Cyclone Public Advisory (TCP)
and Tropical Cyclone Discussion (TCD)
Submitter:
RSMC Miami
Date Submitted:
April 2015
Discussion:
Currently, the eastern Pacific Public Advisory is always issued in the Pacific Time Zone; a holdover from the
days of the eastern Pacific advisories coming out of Redwood City, CA. We’ve received feedback that this is
confusing to the general public since almost all of Mexico is not in the Pacific Time Zone (see map next
page). This problem was highlighted in Odile when some people in Cabo San Lucas (in Mountain Daylight
Time) were confused about the landfall time of the cyclone - a situation that endangers public safety. Clearly,
this problem is even worse when a cyclone is farther east, with most of the rest of Mexico in Central Time.
The Mexican Weather Service enthusiastically supports this change.
Action
Forward to WMO RAIV
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4. Title
Informational Item: Use of Mixed Case for Tropical Cyclone Public Advisories, Tropical Cyclone
Updates, and Monthly Tropical Cyclone Summaries
Submitter:
RSMC Miami
Date:
April 2015
Discussion:
In 2014, RSMC Miami successfully transitioned from all capital letters to mixed case for our Tropical
Weather Outlooks and Tropical Cyclone Discussions. This has been very well received by our customers and
there have been no reported issues in receiving the products with mixed case. RSMC issues other tropical
cyclone products that have a significant component of text in sentence / paragraph form.
Action:
RECOMMENDATIONS:
1. Transition the following additional products to mixed case as soon as resources permit: Tropical
Cyclone Public Advisory (TCP), Tropical Cyclone Update (TCU), and Monthly Tropical Cyclone Weather
Summary (TWS). Examples of each product are given on the next few pages.
2. RSMC determine whether these products can be updated for the 2015 season, and if so, issue appropriate
public notices.
Tropical Cyclone Public Advisory (TCP)
ZCZC MIATCPAT1 ALL
TTAA00 KNHC DDHHMM
BULLETIN
TROPICAL DEPRESSION ONE ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL
AL012014
1100 PM EDT MON JUN 30 2014
...TROPICAL DEPRESSION FORMS EAST OF FLORIDA...
...TROPICAL STORM WATCH ISSUED FOR THE COAST OF EAST-CENTRAL
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FLORIDA...
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-------------------------------------------------------------------------------LOCATION...27.6N 79.1W
ABOUT 105 MI...170 KM ESE OF CAPE CANAVERAL FLORIDA
ABOUT 210 MI...335 KM NNW OF THE NORTHWESTERN BAHAMAS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...SW OR 225 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES
WATCHES AND WARNINGS
---------------------------------------CHANGES WITH THIS ADVISORY:
A Tropical Storm Watch has been issued for the east coast of Florida from Fort Pierce northward to just south
of Flagler Beach.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Watch is in effect for...
* East coast of Florida from Fort Pierce to Flagler Beach
A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case
within 24 to 36 hours.
Interests elsewhere along the southeast coast of the United States should monitor the progress of this system.
For storm information specific to your area, including possible inland watches and warnings, please monitor
products issued by your local National Weather Service forecast office.
DISCUSSION AND 48-HOUR OUTLOOK
-------------------------------------------------------At 1100 PM EDT, 0300 UTC, the center of Tropical Depression One was located near latitude 27.6 North,
longitude 79.1 West. The depression is moving toward the southwest near 2 mph (4 km/h). A slow west to
west-northwest motion is forecast to begin by Tuesday morning. A turn toward the northwest then north is
forecast by Wednesday. On the forecast track, the center of the depression is expected to remain offshore and
move east of the east-central coast of Florida during the next day or so. The system is forecast to pass east of
northeastern Florida on Wednesday and Wednesday night.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Gradual strengthening is expected
during the next 48 hours, and the depression is forecast to become a tropical storm on Tuesday.
The estimated minimum central pressure is 1009 mb (29.80 inches).
HAZARDS AFFECTING LAND
-----------------------------------------WIND: Tropical storm conditions are possible within the watch area by late Tuesday.
RAINFALL: The depression is expected to produce total rainfall accumulations of 1 to 3 inches, mainly
across east-central Florida and northeastern portions of the Florida peninsula with possible isolated maximum
amounts of 5 inches through Wednesday. Rainfall amounts of 2 to 4 inches with isolated maximum amounts
of 6 inches are possible over portions of the northern Bahamas through Wednesday.
NEXT ADVISORY
-------------------------Next Intermediate Advisory at 200 AM EDT.
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5. Title
Informational Item: Change Tropical Weather Outlook (TWO) Categories
Submitter:
RSMC Miami
Date:
April 2015
Discussion:
RSMC Miami currently divides the probability space for its TWO into three bins, where “low” corresponds to
0-20% chance of genesis, “medium” corresponds to 30-50% chance, and “high” corresponds to 60-100%
chance. These bins do not represent an even partition of the probability space for two reasons: first, when the
product was first introduced there was a decrease in skill above 20% such that verifications by bins were
improved when the low bin was limited to 20% and below. And second, there was a desire to highlight all
systems that were expected to develop and so they were grouped into a single bin.
Over the past few seasons, RSMC Miami’s genesis forecast skill has improved and become more uniform
across the probability space, and there is no longer a need to so sharply constrain the “low” category. In
addition, feedback from the Emergency Manager community suggests that moving a system into the medium
category (currently 30%) creates a level of anxiety that is perhaps not warranted for a system that still has a
less than one-in-three chance of developing. Media reaction to the relatively low thresholds for the medium
and high categories also tends to overly hype systems. RSMC Miami therefore feels it is time to redefine the
bins with a more even distribution that will not overly heighten concerns of users.
Action
RECOMMENDATIONS: Redefine the TWO genesis bins as follows:
6. Title
Make Experimental Graphical Tropical Weather Outlook (XGTWO) Graphic Operational
Submitter:
RSMC Miami
Date:
April 2015
Discussion:
RSMC Miami experimentally issued a graphical 5-day Tropical Weather Outlook in 2014. Feedback from
users was highly positive, and RSMC Miami would like to declare this product operational for 2015. Only
minor cosmetic changes to the product are planned for 2015.
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7. Title
Watches, Warnings, and Forecasts Prior to Tropical Cyclone Formation
Submitter:
RSMC Miami
Date:
April 2015
Discussion:
RSMC Miami has identified cases when it would have been appropriate to issue a tropical storm warning
(because tropical storm conditions were expected within an area during the next 36 hours), but where issuing
the warning was not possible because a tropical cyclone had not yet formed. A team was formed to engage
the user community to learn user concerns, identify potential solutions and develop a path forward and report
findings. This item provides information on a potential path forward that has been recommended by the team.
This item proposes that the RSMC Miami provide the option to issue tropical storm or hurricane warnings for
appropriate land areas when tropical storm or hurricane conditions are expected in association with a
disturbance that has a significant potential of becoming a tropical cyclone during the following 48
hours. Aside from expanding their applicability to potential tropical cyclones, the regular warning criteria
would apply (issue when tropical storm / hurricane conditions were expected within 36 hours).
We recognize that expanding the use of tropical cyclone watches and warnings, primarily for lower-end
events, has the potential to reduce their long-term effectiveness through false alarms and minimal
impacts. For this reason, we are not recommending the issuance of tropical storm watches for potential
tropical cyclones. However, the proposal would allow a hurricane watch to accompany a tropical storm
warning when appropriate. Or put another way, disturbances would never be associated with only a tropical
storm watch, or with a hurricane watch in the absence of a concurrent tropical storm warning.
In order to minimize the chances of warning type changes during an event, we’d expect that this option would
be primarily exercised for threats when the Tropical Weather Outlook (TWO) 48-hour genesis probability was
at least 50%. For systems that are expected to produce tropical-storm-force winds but have a 20% or less
chance of genesis, we’d expect that local USA WFO products would be used and the tropical option would
not be exercised. Systems with intermediate genesis likelihoods would be evaluated on a case-by-case basis.
In order to support public dissemination of warnings before tropical cyclone formation, the RSMC Miami
would produce a 3-day track and intensity forecast for those disturbances requiring tropical storm or hurricane
warnings for the United States. Although RSMC Miami doesn’t issue warnings for other countries, we would
also issue a 3-day forecast when tropical-storm-force winds or greater were expected over international land
areas. The forecast would be publicly issued through the standard RSMC advisory products. The advisory
“package” would include a public advisory, discussion, wind speed probabilities (text and graphic), tropical
disturbance watch / warning text product (TCV), forecast cone, and a forecast advisory that would provide
forecast positions, intensities, and standard wind radii at 12-, 24-, 36-, 48-, and 72-hours into the
future. These advisory packages would be issued at the normal advisory times of 0300, 0900, 1500, and 2100
UTC. Advisory packages would be issued until watches and / or warnings were discontinued or the threat of
tropical storm force winds at international locations sufficiently diminished. If the system becomes a tropical
cyclone, tropical cyclone advisory packages with a 5-day forecast would begin.
A draft plan has been created that provides greater detail on how tropical disturbance forecasts and associated
warnings would be disseminated and numbered. A list of technical development items related to this proposal
has also been established.
Recommendation:
A U.S. NWS team has been established to work through technical and dissemination issues associated with
the implementation of tropical cyclone watches / warnings and advisories before
formation. Recommendations will be adjudicated and discussed at the 2015 USA NOAA Hurricane Meeting
in preparation for a potential 2016 implementation. With that in mind, there will be a requirement to identify
those disturbances. The Greek alphabet is currently reserved to name cyclones in active years like 2005.
However, the designation is rarely used, and RSMC Miami proposes to use the Greek alphabet to identify
these disturbances described above. In place of the Greek alphabet, a supplemental list of regular names
would be used when the standard list is exhausted.
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