October Temperatures
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The graph to the left
shows monthly mean temperature averaged across the contiguous
United States based on long-term data from the U.S. Historical
Climatology Network (USHCN). The value for
2002 is estimated from preliminary Climate Division data using the
first difference approach. October 2002 ranked as the 14th coldest October in
the 1895 to present record. The preliminary nationally averaged
temperature was 52.6° F (11.4° C) which was 2.2° F
(1.2° C) below the long-term mean. |
Much below average
warmth occurred in 12 contiguous states in October. No statewide
mean temperature records were set for the month, though Minnesota
and South
Dakota had their third coldest October since 1895 and both
states had their coldest October since 1925. Only one state
(Florida) had much above average temperatures for the month while 6
other southeastern states had significantly above average
temperatures and 9 states out of the lower 48 states had near
average temperatures.
As can be seen in a map of divisional temperature (below right),
significantly warmer than average temperatures were evident in all
but one Gulf coast division, as well as along the southeastern and
mid-Atlantic coastal areas. This is in sharp contrast to the entire
mid-section of the country from the Canadian border south to
central Texas which had much below average temperatures. The
pattern of warmth and cold in the contiguous U.S. in October
broadly corresponded with the mean
500mb height and anomalies chart. This shows that well below
normal 500mb heights existed across the upper Midwest/ northern
Great Plains, which was associated with the much lower than average
temperatures in October. It was the first October in four years
that temperatures in Alaska
were well above normal (more than 7°F) relative to the period
1971-2000. This was a reflection of the much above average 500mb
height anomalies over the state of Alaska extending well down
the west coast of Canada. It was the warmest October in Alaska
since 1938, and it is only the 8th time on record that Anchorage
has had no snow in October. (See the October North America snow
summary page for further details) |
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Temperature
Departures
The map to the right,
based on over 500 airport stations, shows departures from the
1971-2000 normal temperatures for October 2002. Some of the largest
widespread negative departures (greater than 7.5°F
[4.2°C]) occurred in the Upper Mississippi Valley and Northern
Great Plains. A new cold temperature record was set in Williston,
ND on October 30th with a low of -9°F, breaking the old record
of -3°F set in 1895 and equalled in 1991. A new record low
maximum daily temperature was also recorded in Denver at 18°F
on the 30th, and Marquette, Michigan had its coldest October on
record with an average of only 37.9°F. This just falls below
the previous record of 38°F set in 1988. See NCDC's Monthly
Extremes web-page for more records.
Widespread positive temperature anomalies were limited to the
southeastern quadrant of the country and the Gulf Coast. An
animated map of daily temperature
anomalies shows temperature variability throughout the month of
October. |
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August-October 2002
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The graph to the left
shows mean temperature averaged across the contiguous United States
based on long-term data from the U.S. Historical Climatology
Network (USHCN). The value for
August-October 2002 is estimated from preliminary Climate Division
data using the first difference approach. August-October 2002 ranked as the 36th
warmest such period in the 1895 to present record. The preliminary
nationally averaged temperature for August-October 2002 was
64.6° F (18.1° C) which was 0.3° F (0.2° C)
above the long-term mean. |
Despite the cooler than average October in many states, statewide
mean temperatures for the August-October period were warmer
than average in the east and the Southwest with 5 eastern states
(New
Hampshire, Rhode
Island, New
Jersey, Vermont
and Florida)
having much above average temperatures for the 3 months. A further
23 states have significantly above average temperatures.
Significantly below average statewide
mean temperatures occurred in 10 states with Montana
average temperatures falling into the much below average category.
When broken down by climate division (see map to the right), there
are scattered divisions which were significantly warmer than
average during this period in most eastern states althouth no
record warm or cold divisional temperatures averaged over the
August-October period occurred.
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January-October 2002
(year-to-date)
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The graph to the left
shows mean temperature averaged across the contiguous United States
based on long-term data from the U.S. Historical Climatology
Network (USHCN). The value for
January-October 2002 is estimated from preliminary Climate Division
data using the first difference approach. January-October 2002 ranked as the 14th
warmest such period in the 1895 to present record. The preliminary
nationally averaged temperature for January-October 2002 was
56.8° F (13.8° C) which was 1.1° F (0.6° C)
above the long-term mean. |
Statewide
mean temperature for the January-October period was much above
average for 18 states, with Delaware
having its record warmest January-October in 108 years. Connecticut,
New
Jersey and Maryland
all had their second warmest January-October on record.
Significantly above average statewide
mean temperatures also occurred in 22 out of the remaining 30
contiguous states with only Montana averaging below normal
temperatures for the year-to-date. Seven states had near average
temperatures for January-October. When broken down by climate
division, divisions in Maryland, Virginia, Delaware, New York,
and Massachusetts reached record warmth for the January-October
period, while cooler than average divisional temperatures were
limited to Montana, Idaho and one division each in Wyoming, South
Dakota, Texas, Oklahoma and Arkansas.
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National Temperatures -
November 2001-October 2002
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The graph to the left
shows mean temperature averaged across the contiguous United States
based on long-term data from the U.S. Historical Climatology
Network (USHCN). November
2001-October 2002 ranked as the 4th warmest such
period in the 1895 to present record. The preliminary nationally
averaged temperature was 54.4°F (12.4°C) which was
1.6°F (0.9°C) above the long-term mean. |
Record warmth occurred
in six states (RI, CT, NJ, DE, MD and OH) averaged over the last
twelve months. The pattern of state-averaged monthly temperature
can be seen in the map to the right. Twenty-one other states ranked
in the top ten warmest such periods. Only three states had
near-average temperatures for November-October (MT, ID and
WY). |
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October
Precipitation
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The graph to the left
is a time series depicting precipitation averaged across the
contiguous U.S. Based upon preliminary precipitation data, October
2002 was much wetter than average, ranking 7th wettest - the
most anomalously wet month since January 1999. There has been
no significant trend in mean national October precipitation over
the last century. |
There was considerable
regional variability in precipitation across the country. Nine
states in the eastern half of the country (Mississippi,
Texas,
Louisiana,
Kansas,
Kentucky,
West
Virginia, Maryland,
Delaware,
and New
Jersey) received much above average rainfall in October, while
four states (California,
Oregon,
Washington
and Idaho)
received much below average rainfall this month. Louisiana,
Texas
and Delaware
were second wettest on record for the month of October. Substantial
drought alleviation has occurred in many eastern states and though
states such as Colorado also received above average precipitation
this month, it will still take many months of above average or near
average rainfall to alleviate the
long-term
drought in that state and others in the Southwest
and West.
Some of the above-average rainfall in the eastern half of the
country was a result of Hurricane Lili as
it moved inland off the Gulf of Mexico on the 3rd. More details on
October hurricanes and tropical storms can be found on the hurricane season
page. |
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In Corpus Christi, Texas, on October 24th, a major storm which
spawned several tornadoes led to the death of at least one
person and injuries to over a dozen others. One tornado touched
down in Del Mar college campus in the town and the path stretched a
further two to three miles west and north of the campus. This
followed on the heels of severe storms the previous day and Texas
was hit with further storms later in the month mostly in the
Houston area. These latter storms also produced at least one
tornado and dumped up to 9 inches of rain in parts of the Houston
Metro region. |
Earlier in the month, on October 3rd, Hurricane
Lili came ashore in western Louisiana bringing additional rain
to areas already affected by Tropical Storm
Isidore in September. More rainfall later in October led to a
rank of second wettest October on record for Louisiana and Texas.
Further details on flooding and rainfall in the Southeast and parts
of the Gulf Coast are given on the Atlantic hurricane
page, as they relate to landfalling tropical storms in
October.
As the North American snow season got underway in October, some
precipitation fell as snow, especially in the Northern Great Plains
and the upper Midwest. More details of snowfall in October can be
found on the snow
season page
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The graph to the left
is a time series depicting precipitation averaged across the
primary
hard red winter wheat belt. The growing season runs from
October to February for the hard red winter wheat and preliminary
data indicate that precipitation was much above average for the
first month of the growing season in 2002. |
Precipitation
Departures
The map to the right,
based on more than 500 airport stations, shows October 2002 total
precipitation as a percent of the 1971-2000 station normals. Above
normal precipitation generally occurred in the South through the
Mississippi Valley, the Tennessee/Ohio Valley regions, and much of
the east coast with more than 190% of normal precipitation falling
in some areas. A record wet month was recorded at several stations
in Louisiana for example. A monthly total of 21.44 inches at Lake
Charles, LA, broke the old record set in 1970 by 4.16 inches.
Lafayette, LA also received 2.62 inches more than the previous old
record, totalling 18.27 inches for October 2002.
Dryness extended across most of the West and Northwest where as
little as 25% of normal precipitation was recorded. The northern
Great Plains were also dry this month, with less precipitation than
normal also occurring in the lower peninsula of Michigan and
Florida. At Miami International Airport, a new monthly minimum
rainfall record was set for October at 0.71 inches, breaking the
previous record of 1.12 inches, set in 1925. More city and state
extremes for the month can be found at NCDC's Extremes
Page. |
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Last 3 months
(August-October)
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The graph to the left
is a time series depicting precipitation averaged across the
contiguous U.S. Based upon preliminary precipitation data,
August-October 2002 was wetter than average, ranking 11th wettest
in the last 108 years. This contrasts sharply with October of 2000
and 1999 and belies considerable regional variability as can be
seen from the maps below. |
Much below average precipitation, over
August-October, occurred in 5 western states (CA, NV, ID, OR, and
WA) in 2002. Four other states (AZ, WY, NH, and ME) also received
siginificantly below average precipitation. Six states received
much above average rainfall with Mississippi
having a record wet three months. Some of the rainfall over the
three month period came in September from Tropical Storm Isidore
and is discussed further on the Atlantic hurricane
season web-page. |
National Precipitation -
January-October 2002 (year-to-date)
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The graph to the left
is a time series depicting precipitation averaged across the
contiguous U.S. Based upon preliminary precipitation data,
January-October 2002 was drier than average, ranking 28th driest in
the last 108 such periods. The last 3 January-October periods have
averaged below the long term mean precipitation. |
The long term dryness
becomes more apparent when looking at an average of the last 10
months. Record dryness occurred in 3 states (CO, CA and AZ) from
January to October. The pattern of state-averaged year-to-date
precipitation can be seen in the map to the right. Six other states
ranked in the top ten driest such periods. More information on
drought analysis for these states and others can be found on
NCDC's
Drought Pages. Two states (MN and WI) received much above
average rainfall averaged over the last 10 months, with a third
wettest January-October occurring in Wisconsin. |
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