A lake effect snow watch was a bulletin issued by the
National Weather Service
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...
in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
to warn of heavy
snow
Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes.
It consists of frozen crystalline water throughout ...
fall amounts that will be possible from convective snow generated by cold
air mass
In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to l ...
es passing over unfrozen lakes (
lake effect snow
Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water. The lower layer of air, heated up by the lake water, picks up water vapor from the lake and rises up through ...
). The criteria for amounts may vary over different
county
A county is a geographic region of a country used for administrative or other purposes Chambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...
warning areas.
On October 2, 2017, issuance of the Lake Effect Snow Watch has been discontinued, and a
winter storm watch is now issued when the above criteria are expected to be met.
Example
MNZ020-037-181845-
/O.NEW.KDLH.LE.A.0004.081219T0600Z-081220T0600Z/
SOUTHERN LAKE/LAKESHORE-CARLTON/SOUTHERN ST. LOUIS-
443 AM CST THU DEC 18 2008
...LAKE EFFECT SNOW WATCH IN EFFECT FROM LATE TONIGHT THROUGH
FRIDAY EVENING...
THE NATIONAL WEATHER SERVICE IN DULUTH HAS ISSUED A LAKE EFFECT
SNOW WATCH...WHICH IS IN EFFECT FROM LATE TONIGHT THROUGH FRIDAY
EVENING.)
LAKE EFFECT SNOW WILL DEVELOP AROUND MIDNIGHT TONIGHT...AND LAST
THROUGH MUCH OF FRIDAY AND INTO FRIDAY EVENING. THE HEAVIEST OF
THE SNOW WILL FALL ALONG THE HIGHER TERRAIN FROM DULUTH TO SILVER
BAY...WHERE THE POTENTIAL EXISTS FOR UP TO 8 INCHES IN ISOLATED
AREAS. THE HEAVIEST OF THE SNOW LOOKS TO FALL EARLY FRIDAY MORNING
AROUND THE TIME OF THE MORNING COMMUTE.
A LAKE EFFECT SNOW WATCH MEANS THE POTENTIAL EXISTS FOR HEAVY
ACCUMULATION OF LAKE-EFFECT SNOW. TRAVEL AND COMMERCE MAY BE
SIGNIFICANTLY AFFECTED. YOU ARE ENCOURAGED TO STAY CURRENT WITH
THE LATEST WEATHER INFORMATION REGARDING THIS DEVELOPING WINTER
STORM VIA LOCAL TELEVISION...RADIO...THE INTERNET...OR NOAA
WEATHER RADIO.
$$
LONKA
See also
*
Lake effect snow advisory
*
Lake effect snow warning
*
Snowsquall
A snowsquall, or snow squall, is a sudden moderately heavy snowfall with blowing snow and strong, gusty surface winds. It is often referred to as a whiteout and is similar to a blizzard but is localized in time or in location and snow accumul ...
References
External links
National Weather ServiceFederal Emergency Management AgencyMeteorological Service of Canada{{SevWea nav
Weather warnings and advisories