[nws-changes] 20130916: LAMP comments Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20130916: LAMP comments Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Mon, 16 Sep 2013 06:55:52 -0600

-------- Original Message --------

718
NOUS41 KWBC 161133
PNSWSH

National Weather Service Headquarters Washington DC
732 AM EDT Mon Sep 16 2013

         - Family of Services
         - NOAA Weather Wire Service
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         - NOAAPORT
         Other NWS partners and NWS employees

         Science Plans Branch Chief
         Office of Science and Technology

for Experimental LAMP Convection and Upgraded Lightning
Products

Aviation Model Output Statistics Program (LAMP) Convection and
Upgraded Lightning products through November 15, 2013.

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:

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:

National Weather Service
Meteorological Development Laboratory
Judy.Ghirardelli@xxxxxxxx
301-713-0056 x194