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Service Change Notice 24-47
National Weather Service Headquarters Silver Spring MD
230 PM EDT Thu May 2 2024

To:  Subscribers:
  -NOAA Weather Wire Service
  -Emergency Managers Weather Information Network -NOAAPORT
  Other NWS partners and NWS employees

From:  Marina Timofeyeva
  Chief, Climate Services Branch

  Bruce Entwistle
  Chief, Aviation and Space Weather Services Branch

Subject:  Moving Downtown Los Angeles Weather Observations Site to
the
  Frank Hotchkin Memorial Training Center on May 20, 2024

Effective Thursday, May 20, 2024 around 1500 Universal Coordinated
Time
(UTC) (8 AM PDT), the official Downtown Los Angeles weather
observations
site (KCQT) will be relocated to the Frank Hotchkin Memorial Training
Center on the south side of Dodger Stadium. Observations collected at
KCQT
support NWS forecast activities, the climate record for Downtown Los
Angeles, certain aviation operations, and needs of the meteorology,
hydrology, and climatology research communities.

Since 1999, the NWS has been collecting observations  temperature,
precipitation, dew point, pressure and wind speed and direction
using an
Automated Surface Observing System (ASOS) located on the campus of
the
University of Southern California (USC). This location is only about
10
miles from the Pacific Ocean, which has had a significant influence
on
temperature, humidity, and precipitation measurements. The site
location
is suboptimal in characterizing Downtown Los Angeless true weather
and
climate conditions. The core of Downtown Los Angeles is located
farther
inland from the coast and current site of KCQT. Gathering
observations
farther inland at the Frank Hotchkin Memorial Training Center is
expected
to better represent the weather and climate of Downtown Los Angeles.
Downtown Los Angeles has one of the longest periods of record of
weather
observations in the West, dating back nearly 150 years to July 1877.
The
upcoming move to the Frank Hotchkin Memorial Training Center returns
the
Downtown Los Angeles observing site to a location near the previous
Los
Angeles Civic Center station, which was active from 1964 to 1999. The
site
relocation will help build on the climate records that are more
representative of Downtown Los Angeles.
Moreover, the move will provide better sampling of weather conditions
conducive for the spread of brush fires closer to the foothills, and
thus
better assist NWS meteorologists in forecasting fire-weather
conditions.

The observing equipment will also change from an ASOS to different
equipment that is also used for the Cooperative Observer Program
(COOP).
This change is necessary to align with infrastructure at Frank
Hotchkin
Memorial Training Center. The change in equipment type is not
expected to
significantly change measurements of meteorological or climatological
variables.

With the change of equipment from ASOS to COOP, there will no longer
be a
WMO Heading or AWIPS ID for real-time Downtown Los Angeles weather
observations. Data collected from the Frank Hotchkin Memorial
Training
Center will still be available online via the NWS Weather and Hazards
Data
Viewer (https://www.wrh.noaa.gov/map/?wfo=lox) under the new
equipment
identification FHMC1. The data from the new site will also be
provided
in the Hourly Weather Roundup under L.A. DOWNTOWN
(https://www.weather.gov/wrh/TextProduct?product=loxrwrca) without
the sky
condition and visibility provided. Aside from real-time weather
observations, WMO Headings and AWIPS IDs will switch from using
CQT to
FHM around or shortly after the completion of the observing
site
relocation. This applies to the daily Climate Report (CLICQT changing
to
CLIFHM), the Preliminary Local Climatological Data WS Form F-6
(CF6CQT
changing to CF6FHM), and the monthly Climate Report (CLMCQT changing
to
CLMFHM).

The National Weather Service thanks our partners at the Los Angeles
City
Fire Department for their collaboration and support of relocating the
observation site. We also thank the USC for housing our weather
observation site for the past 25 years. Observations gathered at USC
have
greatly contributed to the National Weather Services understanding
of
weather conditions to complete its mission of protecting life and
property.

The NWS will hold a news conference at the Frank Hotchkin Memorial
Training Center to commemorate the Downtown Los Angeles observing
site
relocation and to discuss factors that lead to the move.

For questions regarding the relocation of the official Downtown Los
Angeles weather observation site or the news conference, please
contact:

 Dr. Ariel Cohen, Meteorologist in Charge
 National Weather Service Los Angeles/Oxnard, California
 Oxnard, CA
 805-988-6617
 ariel.cohen@noaa.gov
Resource:
Downtown Los Angeles can experience large swings in meteorological
observations, even across small distances. In 2000, David Bruno, Lead
Meteorologist at NWS Los Angeles/Oxnard, published, Climate of Los
Angeles, California, to identify and document this phenomenon.
Data from
this study was factored into the decision to relocate the site. You
may
access the publication using this link:
https://www.weather.gov/media/wrh/online_publications/TMs/TM-261.pdf.


National Service Change Notices are online at:

http://www.weather.gov/notification