NOUS41 KWBC 161133
PNSWSH
Public
Information Statement, Comment Request
National Weather
Service Headquarters Washington DC
730 AM EDT Mon
Sep 16 2013
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:
Soliciting Public Comments Through November 15, 2013,
for
Experimental LAMP Convection and Upgraded Lightning
Products
The NWS is
seeking user feedback on the experimental Localized
Aviation Model
Output Statistics Program (LAMP) Convection and
Upgraded
Lightning products through November 15, 2013.
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 guidance consists 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 LAMP
convection guidance is a new product, while the LAMP
lightning guidance has been upgraded and is proposed
as a
replacement for the current LAMP
"thunderstorm" guidance. The
name of the thunderstorm product 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 guidance, the LAMP
lightning guidance will also be sampled to a 5-km
grid. The
4 category product will be converted to a Yes/No categorical
product so as to continue to support users who are
dependent on
the LAMP thunderstorm guidance, currently
available on a 5-km
grid and provides a Yes/No categorical product.
Objective scoring
of the LAMP convection and lightning
probabilities reveals substantial forecast skill and sharpness,
and good reliability. For instance, the skill
and sharpness of
the convection and lightning probabilities are
much better than
that for current operational LAMP thunderstorm
probabilities even
though the convection/lightning and thunderstorm
models have a
similar design. The superior performance for
convection and the
upgraded lightning guidance is attributed to
supplemental
dynamical predictor input from the NCEP North American
Mesoscale
(NAM) model, as
both LAMP (convection/lightning and thunderstorm)
models use dynamical predictors from the large
scale NCEP Global
Forecast System
(GFS). The NAM predictor input also provides
additional spatial resolution.
More information
about these products, as well as links to the
data and images, can be found here:
http://www.nws.noaa.gov/mdl/gfslamp/docs/cnvltg_info.php
The products are
available in GRIB2 format at the following site:
http://www.nws.noaa.gov/mdl/lamp/cnvltg_downloads.php
With this
proposal, the format of the LAMP text bulletin (AWIPS
PIL of “LAV”)
will change. The LAMP lightning
probabilities and
four category guidance interpolated to stations
will replace the
thunderstorm probability and two category guidance in the
LAMP
text bulletin.
The LAMP convection probabilities and four
category guidance interpolated to stations will be
added to the
LAMP
text bulletin. An example of the current LAMP bulletin
compared to the proposed LAMP bulletin can be found
here:
http://www.nws.noaa.gov/mdl/gfslamp/docs/lavtxtdiff.php
The new LAMP
bulletins are available at the following site:
http://www.nws.noaa.gov/mdl/gfslamp/lavlamp_cnvltg.shtml
The LAMP
lightning probability and four category guidance
converted to the two category Y/N guidance will be
interpolated
to stations and will replace the thunderstorm
probability and two
category guidance in the LAMP BUFR message file. Therefore the
format of the new lightning guidance will look the
same as the
format of the current thunderstorm guidance in the
BUFR files so
as to continue 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. The link for the BUFR data containing the
upgraded lightning data will be made available on the
information
page URL above when available.
Users are
encouraged to provide feedback on these experimental
products by using the brief survey and comment form
available on-
line at:
http://www.nws.noaa.gov/survey/nws-survey.php?code=LCULG
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
$$