History of Pacific Northwest Heat Waves: Synoptic Pattern and Trends

2013 ◽  
Vol 52 (7) ◽  
pp. 1618-1631 ◽  
Author(s):  
Karin A. Bumbaco ◽  
Kathie D. Dello ◽  
Nicholas A. Bond
Keyword(s):  
Pacific Northwest ◽  
Heat Wave ◽  
Heat Waves ◽  
Precipitable Water ◽  
The United States ◽  
Historical Record ◽  
Cascade Mountains ◽  
Daily Data ◽  
Maximum Temperatures ◽  
Heat Events

AbstractA historical record of Pacific Northwest (defined here as west of the Cascade Mountains in Washington and Oregon) heat waves is identified using the U.S. Historical Climate Network, version 2, daily data (1901–2009). Both daytime and nighttime events are examined, defining a heat wave as three consecutive days above the 99th percentile for the maximum and minimum temperature anomalies separately. Although the synoptic characteristics of the daytime and nighttime heat events are similar, they do indicate some differences between the two types of events. Most notable is a stronger influence of downslope warming over the Cascade Mountains for the daytime events versus a more important role of precipitable water content for the nighttime events, presumably through its impact on downward longwave radiative fluxes. Current research suggests that the frequency and duration of heat waves are expected to increase in much of the United States, and analysis of the heat events reveals that a significant, increasing trend in the frequency of the nighttime events is already occurring in the Pacific Northwest. A heat wave occurred in 2009 that set all-time-record maximum temperatures in many locations and ranked as the second strongest daytime event and the longest nighttime event in the record.

Extreme Heat

2021 ◽  
Keyword(s):  
Heat Wave ◽  
Global Climate ◽  
Geographic Location ◽  
Weather Conditions ◽  
The United States ◽  
Extreme Heat ◽  
Local Climate ◽  
Extreme Heat Events ◽  
The World ◽  
Heat Events

Extreme heat events (EHEs) are periods of high temperatures and humidity that are considered to be unusual for a specific geographic location. For example, in 1995 an extended heat wave in Chicago, Illinois, in the United States was blamed for the deaths of 550 citizens. Most of the dead were elderly, poor individuals who may not have realized that heat could kill, or who had no means of mitigating the rising temperatures in their homes or any way to escape to a cooler environment. In 2003, Europe was subjected to an EHE that is estimated to have resulted in the deaths of 70,000, with 15,000 of those deaths in Paris, France. “Extreme heat” is a relative term. Individuals adapt to their local climate, so it is difficult to use an absolute number to describe the conditions meteorologists consider a relative change from past conditions. The Centers for Disease Control and Prevention (CDC) defines extreme heat as “summertime temperatures that are substantially hotter and/or more humid than average for location at that time of year.” According to the Public Health Institute’s Center for Climate Change, the state of California defines extreme heat days as those days above the 98th percentile of maximum temperatures based on 1961–1990 data for a specific location. Crucial to understanding extreme heat events is the collection of data about temperature and humidity. The US Global Change Research Program provides heat wave data spanning 1961 to 2018. The site links to a variety of programs related to global climate modeling. The National Resources Defense Council is a nongovernmental organization that has excellent maps which show change over time in the frequency of extreme heat events that overlay the human impact of these events. The National Centers for Environmental Information provides graphic data of current weather conditions along with lists of significant climate anomalies. The site has links to weather records and tools. All of these sites rely on the National Oceanic and Atmospheric Administration for their data. There are equivalent agencies all over the world. The World Meteorological Organization, part of the United Nations, is also a valuable resource for data.

scholarly journals An Analysis of the Prevalence of Heat Waves in the United States between 1948 and 2015

2018 ◽  
Vol 57 (7) ◽  
pp. 1535-1549 ◽  
Author(s):  
Evan M. Oswald
Keyword(s):  
United States ◽  
Heat Wave ◽  
Great Plains ◽  
Heat Waves ◽  
Estimation Method ◽  
The United States ◽  
Northern Great Plains ◽  
Strong Increase ◽  
Climate Data ◽  
Nighttime Temperatures

AbstractUnusually hot weather is a major concern to public health as well as other systems (e.g., ecological, economical, energy). This study utilized spatially continuous and homogenized observational surface climate data to examine changes in the regularity of heat waves in the continental United States. This included the examination of heat waves according only to daytime temperatures, nighttime temperatures, and both daytime and nighttime temperatures. Results confirmed a strong increase in the prevalence of heat waves between the mid-1970s and the dataset end (2015), and that increase was preceded by a mild decrease since the dataset beginning (1948). Results were unclear whether the prevalence of nighttime or simultaneous daytime–nighttime heat waves increased the most, but it was clear that increases were largest in the summer. The largest gains occurred in the West and Southwest, and a “warming hole” was most conspicuous in the northern Great plains. The changes in heat wave prevalence were similar to changes in the mean temperatures, and more so in the daytime heat waves. Daytime and nighttime heat waves coincided with one another more frequently in recent years than they did in the 1970s. Some parts of the United States (West Coast) were more likely than other parts to experience daytime and nighttime heat waves simultaneously. While linear trends were not sensitive to the climate dataset, trend estimation method, or heat wave definition, they were mildly sensitive to the start and end dates and extremely sensitive to the climate base period method (fixed in time or directly preceding any given heat wave).

Prediction of Flash Droughts over the United States

2020 ◽  
Vol 21 (8) ◽  
pp. 1793-1810
Author(s):  
Kingtse C. Mo ◽  
Dennis P Lettenmaier
Keyword(s):  
United States ◽  
Soil Moisture ◽  
High Temperature ◽  
Pacific Northwest ◽  
Heat Wave ◽  
Late Summer ◽  
The United States ◽  
Late Spring ◽  
The North ◽  
June July

AbstractWe examine reforecasts of flash droughts over the United States for the late spring (April–May), midsummer (June–July), and late summer/early autumn (August–September) with lead times up to 3 pentads based on the NOAA second-generation Global Ensemble Forecast System reforecasts version 2 (GEFSv2). We consider forecasts of both heat wave and precipitation deficit (P deficit) flash droughts, where heat wave flash droughts are characterized by high temperature and depletion of soil moisture and P deficit flash droughts are caused by lack of precipitation that leads to (rather than being the cause of) high temperature. We find that the GEFSv2 reforecasts generally capture the frequency of occurrence (FOC) patterns. The equitable threat score (ETS) of heat wave flash drought forecasts for late spring in the regions where heat wave flash droughts are most likely to occur over the north-central and Pacific Northwest regions is statistically significant up to 2 pentads. The GEFSv2 reforecasts capture the basic pattern of the FOC of P-deficit flash droughts and also are skillful up to lead about 2 pentads. However, the reforecasts overestimate the P-deficit flash drought FOC over parts of the Southwest in late spring, leading to large false alarm rates. For autumn, the reforecasts underestimate P-deficit flash drought occurrence over California and Nevada. The GEFSv2 reforecasts are able to capture the approximately linear relationship between evaporation and soil moisture, but the lack of skill in precipitation forecasts limits the skill of P-deficit flash drought forecasts.

Mechanisms Associated with Daytime and Nighttime Heat Waves over the Contiguous United States

2020 ◽  
Vol 59 (11) ◽  
pp. 1865-1882
Author(s):  
Natalie P. Thomas ◽  
Michael G. Bosilovich ◽  
Allison B. Marquardt Collow ◽  
Randal D. Koster ◽  
Siegfried D. Schubert ◽  
...  
Keyword(s):  
United States ◽  
Human Health ◽  
Heat Wave ◽  
Heat Waves ◽  
The United States ◽  
Daily Maximum ◽  
Local Threshold ◽  
Dry Conditions ◽  
Heat And Moisture ◽  
Climate Events

AbstractHeat waves are extreme climate events that have the potential to cause immense stress on human health, agriculture, and energy systems, so understanding the processes leading to their onset is crucial. There is no single accepted definition for heat waves, but they are generally described as a sustained amount of time over which temperature exceeds a local threshold. Multiple different temperature variables are potentially relevant, because high values of both daily maximum and minimum temperatures can be detrimental to human health. In this study, we focus explicitly on the different mechanisms associated with summertime heat waves manifested during daytime hours versus nighttime hours over the contiguous United States. Heat waves are examined using the National Aeronautics and Space Administration Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). Over 1980–2018, the increase in the number of heat-wave days per summer was generally stronger for nighttime heat-wave days than for daytime heat-wave days, with localized regions of significant positive trends. Processes linked with daytime and nighttime heat waves are identified through composite analysis of precipitation, soil moisture, clouds, humidity, and fluxes of heat and moisture. Daytime heat waves are associated with dry conditions, reduced cloud cover, and increased sensible heating. Mechanisms leading to nighttime heat waves differ regionally across the United States, but they are typically associated with increased clouds, humidity, and/or low-level temperature advection. In the midwestern United States, enhanced moisture is transported from the Gulf of Mexico during nighttime heat waves.

scholarly journals Satellite and AWS Based Scrutiny of Heat Wave over A.P

2019 ◽  
Vol 8 (4) ◽  
pp. 4719-4722
Keyword(s):  
Heat Wave ◽  
Death Rate ◽  
Andhra Pradesh ◽  
Heat Waves ◽  
Temperature Data ◽  
Sudden Increase ◽  
High Death Rate ◽  
High Death ◽  
Maximum Temperatures ◽  
Day By Day

Extreme events related to heat waves have been increasing day by day in recent years over India. To achieve this, we took the help of the satellite data. In this paper, we analysed maximum temperatures of the heat wave episode which happened during 23 – 26 May, 2015 over Andhra pradesh. Five stations such as nandigama, Kavali, Darsi, Rajamundry and Bapatla were selected and presented in this paper. The reason for selecting these five stations was due to high death rate in this episode. On comparing the both satellite and automatic weather station(AWS) temperature data, the corelation coefficient was 0.80 . There was a sudden increase in the temperatures of about 8 – 130C in the morning hours. Almost 8 – 10 hours with temperatures above 400C lasted causing people expose to high temperatures causing more deaths.

scholarly journals Heat wave–related mortality in Sweden: A case-crossover study investigating effect modification by neighbourhood deprivation

2018 ◽  
Vol 48 (4) ◽  
pp. 428-435 ◽  
Author(s):  
Daniel Oudin Åström ◽  
Christofer Åström ◽  
Bertil Forsberg ◽  
Ana M. Vicedo-Cabrera ◽  
Antonio Gasparrini ◽  
...  
Keyword(s):  
Heat Wave ◽  
Heat Waves ◽  
Warning System ◽  
Daily Maximum ◽  
Neighbourhood Deprivation ◽  
Deprived Neighbourhoods ◽  
Case Crossover ◽  
All Cause Mortality ◽  
Maximum Temperatures ◽  
The Impact

Aims: The present study aimed to investigate if set thresholds in the Swedish heat-wave warning system are valid for all parts of Sweden and if the heat-wave warning system captures a potential increase in all-cause mortality and coronary heart disease (CHD) mortality. An additional aim was to investigate whether neighbourhood deprivation modifies the relationship between heat waves and mortality. Methods: From 1990 until 2014, in 14 municipalities in Sweden, we collected data on daily maximum temperatures and mortality for the five warmest months. Heat waves were defined according to the categories used in the current Swedish heat-wave warning system. Using a case-crossover approach, we investigated the association between heat waves and mortality in Sweden, as well as a modifying effect of neighbourhood deprivation. Results: On a national as well as a regional level, heat waves significantly increased both all-cause mortality and CHD mortality by approximately 10% and 15%, respectively. While neighbourhood deprivation did not seem to modify heat wave–related all-cause mortality, CHD mortality did seem to modify the risk. Conclusions: It may not be appropriate to assume that heat waves in Sweden will have the same impact in a northern setting as in a southern, or that the impact of heat waves will be the same in affluent and deprived neighbourhoods. When designing and implementing heat-wave warning systems, neighbourhood, regional and national information should be incorporated.

scholarly journals Maximum Temperatures and Heat Waves in Mexicali, Mexico: Trends and Threshold Analysis

2016 ◽  
Vol 9 ◽  
pp. ASWR.S32778 ◽  
Author(s):  
Polioptro F. Martínez Austria ◽  
Erick R. Bandala
Keyword(s):  
Climate Change ◽  
Heat Wave ◽  
Heat Waves ◽  
Decision Makers ◽  
Maximum Temperature ◽  
Climate Trends ◽  
Intergovernmental Panel ◽  
Temperature Trends ◽  
Maximum Temperatures ◽  
The City

Maximum temperature trends and the corresponding heat wave thresholds in the northwestern city of Mexicali, Mexico, were analyzed using historical data from the site. We found that there seems to be an upward trend in temperature in the past decades, along with an increased number of days reaching maximum temperatures considered as heat waves. Despite the difficulty of establishing heat wave parameters, the trends of the analyzed field data clearly show their presence, mainly during July and August. This trend is also supported by the analysis of the number of admissions and casualties registered in hospitals in the city of Mexicali. This work is a warning on the frequency and duration of a very important climate change-related effect capable of jeopardizing the health of the population in the region and requiring more attention by decision makers and stakeholders. It also helps to document observed climate trends, as requested by the Intergovernmental Panel for Climate Change.

scholarly journals Summer variation of the UTCI index and Heat Waves in Serbia

2019 ◽  
Author(s):  
Milica M. Pecelj ◽  
Milica Z. Lukić ◽  
Dejan J. Filipović ◽  
Branko M. Protić
Keyword(s):  
Heat Stress ◽  
Heat Wave ◽  
Heat Waves ◽  
Heat Budget ◽  
Meteorological Data ◽  
Climate Index ◽  
Daily Maximum ◽  
Thermal Climate ◽  
Maximum Temperatures ◽  
Novi Sad

Abstract. The objective of this paper is the assessment of bioclimatic conditions in Sebia. A special emphasis has been given to the heat budget bioclimatic Universal Thermal Climate Index (UTCI) whose purpose is to evaluate degree of thermal stress that human body is exposed to during the last twenty years. In addition, the thresholds of daily maximum temperatures are analysed in order to identify increase and frequency of heat waves in Serbia. For this research, daily and hourly (07 h and 14 h) meteorological data from 3 weather station (Mt. Zlatibor, Novi Sad, Niš) are collected for the period 1998–2017. The results show that the most frequent UTCI heat stress categories are strong heat stress and very strong heat stress. The most extreme heat waves events are occurred in 2007, 2012, 2015 and 2017. Moreover, there were three Heat wave events (HWE) in Niš occurred in July, 2007 lasting 3, 10 and 4 days in row. Heat wave events (HWE) In July 2007 (10 days) and July 2012 (9 days) in Niš are occurrences with maximum number of days in row recorded.

scholarly journals Precipitation Deficit Flash Droughts over the United States

2016 ◽  
Vol 17 (4) ◽  
pp. 1169-1184 ◽  
Author(s):  
Kingtse C. Mo ◽  
Dennis P. Lettenmaier
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
Heat Wave ◽  
Great Plains ◽  
Land Surface ◽  
The United States ◽  
Southern Great Plains ◽  
Physical Mechanisms ◽  
The Pacific ◽  
Surface Models

Abstract Flash drought refers to relatively short periods of warm surface temperature and anomalously low and rapid decreasing soil moisture (SM). Based on the physical mechanisms associated with flash droughts, these events are classified into two categories: heat wave and precipitation P deficit flash droughts. In previous work, the authors have defined heat wave flash droughts as resulting from the confluence of severe warm air temperature Tair, which increases evapotranspiration (ET), and anomalously low and decreasing SM. Here, a second type of flash drought caused by precipitation deficits is explored. The authors term these events P-deficit flash droughts, which they associate with lack of P. Precipitation deficits cause ET to decrease and temperature to increase. The P-deficit flash droughts are analyzed based on observations of P, Tair, and SM and ET reconstructed using land surface models for the period 1916–2013. The authors find that P-deficit flash droughts are more common than heat wave flash droughts. They are about twice as likely to occur as heat wave flash droughts over the conterminous United States. They are most prevalent over the southern United States with maxima over the southern Great Plains and the Southwest, in contrast to heat wave flash droughts that are mostly likely to occur over the Midwest and the Pacific Northwest, where the vegetation cover is dense.

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