NOUS41 KWBC 161133



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



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



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:


The products are available in GRIB2 format at the following site:


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:


The new LAMP bulletins are available at the following site:


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:


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:


National Public Information Statements are online at: