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National Oceanic and Atmospheric Administration

Climate of 1999
January: US Statewide Analyses

National Climatic Data Center
February 10, 1999

January'99 US Temps Statewide Ranks
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January 1999 Temperature

Temperatures during January 1999 varied considerably from week to week. The month began with a cold outbreak that affected much of the country east of the Rockies. Temperatures warmed during the latter half of the month, resulting in near-normal January averages over the northeastern quarter of the country. January 1999 ranked among the top ten warmest Januaries on record in five states, including the fifth warmest January on record for Utah and the sixth warmest January since 1895 for Nevada. An additional 30 states ranked within the warmest third of the historical distribution (i.e., among the 35 warmest Januaries out of 105 years).

January 1999 Precipitation

January 1999 was unusually wet from the southern states to the Ohio Valley and Northeast, with 16 states having the wettest to tenth wettest January on record. An additional 18 states ranked within the wet third of the historical distribution (i.e., among the 35 wettest Januaries out of 105 years). January 1999 was dry from southwest Texas to southern California. Arizona ranked in the top ten driest category with the sixth driest January on record, and three other states ranked within the driest third category (top 35 driest Januaries on record). U.S. Statewide Precipitation Ranks, January, 1895-1999
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animated standardized temperature anomaly maps for 1998/02-1999/01
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Despite a cold outbreak that affected a large part of the country east of the Rockies early in the month, January 1999 averaged near normal to much warmer than normal for most of the U.S. The animated maps show the geographical pattern of temperature anomalies for the last 12 months. On these standardized temperature anomaly maps, red indicates areas with mean monthly temperatures much warmer than normal (top 10 percentile), tan indicates warmer than normal (70-90 percentile), light blue indicates colder than normal (10-30 percentile), and dark blue indicates much colder than normal (bottom 10 percentile).
The Palmer Z Index shows how monthly moisture conditions depart from normal (short-term drought and wetness). January 1999 was unusually wet from the southern states to the Ohio Valley and Northeast, much of which had been dry during the last half of 1998. January 1999 was dry from southwest Texas to southern California. The animated maps show the geographical pattern of the moisture anomalies for the last 12 months. On these Z Index maps, the red shading denotes dry conditions while the green shading indicates wet conditions. animated Palmer Z Index maps for 1998/02-1999/01
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Animated Palmer Drought Index Maps
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The Palmer Drought Index Maps show long-term drought and wet conditions. The January 1999 wetness from the southern states to the Ohio Valley and Northeast helped reduce the impact of the long-term drought which had been building over the area during the last half of 1998. The animated maps show how the geographical pattern of the long-term moisture conditions has changed over the last 12 months. On these Palmer Drought Index maps, the red shading denotes drought conditions while the green shading indicates wet conditions.

December 1998 - January 1999 Temperature

U.S. Statewide Temp Ranks, Dec-Jan, 1895-1999
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Unusual warmth dominated most of the country during the two-month period, December 1998 to January 1999. Forty-five of the contiguous 48 states ranked within the top 35 warmest December-Januaries (i.e., the warm third of the historical distribution), and three states had the tenth warmest, or warmer, December-January in 1999.

December 1998 - January 1999 Precipitation

Nature played a regional balancing act for December-January 1998-99 precipitation. On the wet side, Montana ranked within the top ten wettest category with the tenth wettest December-January on record, followed by 26 other states in the top third wettest range (out of 104 December-January periods). On the dry side, Arizona led with the seventh driest December-January, followed by seven other states in the top third driest range (rank of 1 to 34 out of 104 years). U.S. Statewide Precip Ranks, Dec-Jan, 1895-1999
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Line separating section as of the report

For further information, contact:

William Brown
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: william.brown@noaa.gov
-or-
Mike Changery
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: mchangry@ncdc.noaa.gov

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