NOUS41 KWBC 242058
AAA
PNSWSH
Technical
Implementation Notice 13-50 Amended
National Weather
Service Headquarters Washington DC
400 PM EST Mon
Feb 24 2014
To: Subscribers:
- Family of Services
- NOAA Weather Wire Service
- Emergency Managers Weather
Information Network
- NOAAPORT
Other NWS partners and NWS employees
From: Tim McClung
Science Plans Branch Chief
Office of Science and Technology
Subject: Amended:
Changes to the Localized Aviation Model Output
Statistics Program (LAMP) Products and
addition
of Convection
Guidance and upgrade to Lightning
Guidance to postponing implementation
until March 26,
2014, announcing changes to products
in the National
Digital Guidance Database,
and announcing change of
GRIB2 decimal scaling of probabilistic
guidance
Amended for three
actions:
1. Postponing
effective date to be March 26, 2014,
2. Announcing new
filenames for the 2.5 km products in the
National Digital Guidance Database (NDGD)
and the removal of
5 km LAMP products from NDGD
3. Changing GRIB2
decimal scaling from 1 to 0 for the LAMP 2.5 km
probabilistic
gridded guidance
The LAMP
convection and lightning gridded guidance is available
in GRIB2 format. Beginning on or about
Wednesday, March 26,
2014, beginning
with the 1600 Coordinated Universal Time (UTC),
the 2.5 km guidance will be available in
operational NDGD in
these locations:
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/DF.gr2/DC.ndgd/GT.glmp/AR.conus/VP.001-003/
http://weather.noaa.gov/pub/SL.us008001/ST.opnl/DF.gr2/DC.ndgd/GT.glmp/AR.conus/VP.001-003/
with these file names:
- LAMP Lightning
Probabilities, on a 2.5 km grid: ds.plt02.bin
- LAMP Forecast
Potential (no/low/medium/high) of lightning
occurring, on a 2.5
km grid: ds.olt02.bin
- LAMP Convection
Probabilities, on a 2.5 km grid: ds.pcv02.bin
- LAMP Forecast
Potential (no/low/medium/high) of convection
occurring, on a 2.5
km grid: ds.ocv02.bin
The 2.5km
guidance replaces the 5 km guidance.
Therefore, the
following 5 km files will be removed:
- Lightning
Probabilities in a 2-hr period, on a 5 km
grid: ds.pts02.bin
- Thunderstorm
Occurrence (Yes/No) in a 2-hr period, on a 5 km
grid: ds.ots02.bin
from this directory:
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/DF.gr2/DC.ndgd/GT.lampgfs/AR.conus
Note that the 5
km lightning guidance will still be available on
NOAAPort and the Satellite Broadcast Network until
the time when
AWIPS can be
modified to use the 2.5 km lightning guidance.
The LAMP 2.5 km
convection and lightning grids are being
produced experimentally, and on the effective date
will become
operational. At
that time, the decimal scaling in the GRIB2
messages containing probabilistic guidance will
change from 1
to 0.
The original
notice, with a revised date, is below:
Effective on or
about Wednesday, March 26, 2014, beginning
with the 1600 Coordinated Universal Time (UTC)
run, NWS will
change the LAMP guidance to add convection and
upgrade the
lightning product.
On September 16,
2013, NWS solicited comments through
November 15,
2013, regarding these changes:
http://www.nws.noaa.gov/os/notification/pnslampcnvltg.txt
After the comment
period ended, an error was discovered in
the calculation of a lightning-based predictor
associated
with the guidance. The error involved a small
discrepancy in
the timing of the incorporated lightning
strikes. A
correction was implemented Monday, December 23, 2013.
In
addition, a web page has been posted to show the
previous
and corrected guidance, which illustrates the
effect of the
correction for three cases:
http://www.nws.noaa.gov/mdl/gfslamp/lmpltgfix.php
Given this
correction, NWS extended the comment period for
these products to January 16, 2014.
The LAMP
convection and lightning forecast guidance consists
of probability forecasts and categorical
forecasts (referred
to as "potential") in 20-km grid
boxes for 2-h periods in
the 3-to 25-h range over the CONUS. Convection
in a grid box
is defined as the occurrence of either radar
reflectivity of
greater than or equal to 40 dBZ
or at least one cloud-to-
ground (CTG) lightning strike or both during the
2-h valid
period. Lightning occurrence in a grid box is
defined as at
least one CTG lightning strike during the 2-h
valid period.
The categorical
LAMP convection and lightning forecasts
consist of four objectively defined potential
categories
consisting of no, low, medium and high.
The experimental
LAMP convection and lightning guidance
contains guidance on a 2.5 km Lambert Conformal grid
covering the same expanse as the National Digital
Forecast
Database
(NDFD) CONUS grid. Grids
are generated hourly.
The proposed LAMP
convection guidance is a new product,
while the upgraded LAMP lightning product is
proposed to
replace the current LAMP thunderstorm guidance. The
name of
the latter will change from thunderstorm to
lightning, and
the resolution will change from 5 km to 2.5 km.
In addition
to the 2.5 km LAMP lightning grids,
corresponding grids will
be produced for the current 5 km grid. The four
category
product will be converted to a Yes/No categorical
product to
support users who prefer to maintain the
content/format of
the current lightning product.
Users can find
more information about these products, as
well as links to the experimental data and
images, at:
http://www.nws.noaa.gov/mdl/gfslamp/docs/cnvltg_info.php
With this change,
the LAMP text bulletin (AWIPS PIL of LAV)
will change accordingly. The LAMP lightning
probabilities
and the four category guidance (interpolated to
stations)
will replace the current thunderstorm
probabilities and two
category guidance, respectively. Also, NWS will add
the LAMP
convection probabilities and four category guidance
interpolated to stations. An example of the current LAMP
bulletin as compared to the proposed LAMP bulletin is
online:
http://www.nws.noaa.gov/mdl/gfslamp/docs/lavtxtdiff.php
The format of the
new lightning guidance will look the same
as the format of the current thunderstorm
guidance in the
BUFR files to
support users who depend on this data and
format. The Convection Guidance will be added to
the BUFR
file at a later time, and will be announced via a
Technical
Implementation
Notice.
Users are
encouraged to provide feedback on these
experimental products via a survey/comment form available
at:
http://www.nws.noaa.gov/survey/nws-survey.php?code=LCULG
NWS will make a
final decision on implementation these
proposed products in early March 2014. If approved,
this
guidance will be implemented on Tuesday, March 11,
2014, at
1600 UTC and
disseminated on the Satellite Broadcast Network
(SBN),
NOAAPort and the NWS FTP server.
A web page
outlining the LAMP products and the NWS
server directory and file structure can be found
online at:
http://www.nws.noaa.gov/mdl/gfslamp/docs/NWS_tgftp_server_201403.shtml
The communication
identifiers for the BUFR products, ASCII
products, and GRIB2 products are shown below in
Tables 1-3.
A complete list
of gridded LAMP WMO headings is at:
http://www.nws.noaa.gov/mdl/gfslamp/docs/lampheaders_201403.pdf
Table 1:
Communication Identifiers for the GFS-Based LAMP
Products in BUFR
format
Listed below are
the WMO headings. These headings have not
changed.
WMO HEADING REGION
----------- ------
JSMF10 KWNO LAMP BUFR PACIFIC REGION
JSMF11 KWNO LAMP BUFR NORTHEAST REGION
JSMF12 KWNO LAMP BUFR SOUTHEAST REGION
JSMF13 KWNO LAMP BUFR NORTH CENTRAL REGION
JSMF14 KWNO LAMP BUFR SOUTH CENTRAL REGION
JSMF15 KWNO LAMP BUFR ROCKY MOUNTAINS REGION
JSMF16 KWNO LAMP BUFR WEST COAST REGION
JSMF17 KWNO LAMP BUFR ALASKA
Table 2:
Communication Identifiers for the GFS-Based LAMP
Products in ASCII
format
Listed below are
the WMO headings and AWIPS identifier. This
heading has not changed.
WMO HEADING AWIPS ID
----------- --------
FOUS11 KWNO LAVUSA
Table 3a:
Communication Identifiers for the upgraded 5-km
GFS-Based LAMP
Products Lightning products in GRIB2 format
Each GRIB2
product has a unique WMO header. Listed
below
are representations of the WMO headings. These headings
have not changed.
WMO HEADING ELEMENT
----------- -------
LAUXXX KWNO 2-HR PROBABILITY OF LIGHTNING AT 5-KM
LBUXXX KWNO 2-HR CATEGORICAL FORECASTS OF LIGHTNING
OCCURRING at 5-KM
Table 3b:
Communication Identifiers for the new 2.5-km GFS-
Based LAMP
Products Lightning and Convection products in
GRIB2 format
Each GRIB2
product has a unique WMO header. Listed below are
representations of the WMO headings. These headings are new.
WMO HEADING ELEMENT
----------- -------
LCUXXX KWNO 2-HR PROBABILITY OF LIGHTNING AT 2.5-KM
LDUXXX KWNO 2-HR CATEGORICAL FORECAST POTENTIAL OF
LIGHTNING OCCURRING at 2.5-KM
LEUXXX KWNO 2-HR PROBABILITY OF CONVECTION AT 2.5-KM
LFUXXX KWNO 2-HR CATEGORICAL FORECAST POTENTIAL OF
CONVECTION OCCURRING at 2.5-KM
If you have
technical comments or questions, please contact:
Judy Ghirardelli
National Weather
Service
Meteorological
Development Laboratory
301-713-0056 x194
Links to the LAMP
products and descriptions can found at:
http://www.nws.noaa.gov/mdl/gfslamp/gfslamp.shtml
National Public
Information Statements are online at:
http://www.weather.gov/os/notif.htm
$$