Weather Extremes

World and U.S. Anti-cyclonic (High Barometric) Pressure Records

By: weatherhistorian, 9:18 PM GMT on November 26, 2011

World and U.S. Anti-cyclonic (High Barometric) Pressure Records

This blog is a follow up to my previous post on world barometric pressure records. In this case the highest rather than the lowest such. This post completes my recent series on pressure records.

World’s Highest Barometric Measurement

Believe it or not, this is a matter of some controversy. In fact, the WMO Extreme Weather Records Committee (chaired by Randy Cerveny of Arizona State University) is currently undertaking an investigation into this very topic.

The accepted figure for the world’s highest measured barometric pressure reading is 1083.3 mb (32.01”) at Agata, Russia (in Siberia) registered on December 31, 1968. Agata sits at an elevation of 855’ (261 meters) at 66° 53’N, 93° 28’E) on the Central Siberian Plateau. The weather at the time was clear and calm with a temperature range that day of -40°F to -58°F.

Sometime in the late 1990s a small commercial airport was built in the town of Tonsontsengel, Mongolia (48°45′23″N, 98°16′17″E) in Dzavhkan Province at an altitude of 5328’ (1624 meters). Like much of Mongolia the area has been experiencing a boom in natural resource extraction and a hydropower station was built on the banks of the Ider River that flows through this town of some 5,000 souls. Soon after the airport opened some remarkable barometric readings began to be reported from the airport, these pressure readings being, of course, for the sake of commercial aviation. On December 19, 2001 a reading of 1085.7 mb (32.06”) was recorded and then on December 29, 2004 the even higher figure of 1092.1 mb (32.25”) was apparently measured. Both of these figures, of course, would represent world records for high pressure. Furthermore, one may assume the figures were accurate since aircraft would not be able to use the airport in IFR conditions otherwise. The problem with the potential record pressure readings lies with the altitude of the site.



Tonsontsengel lies in a small basin in northern Mongolia at an altitude of 5328’ (1624m). It is possible that this is the location of the highest pressure (1092.1 mb) yet measured on earth. Photographer unknown.

When converting atmospheric pressure to mean sea level (in order to have homogeneous readings regardless of elevation) a formula is used to calculate such. This formula assumes a standard lapse rate of 6.5°C for every kilometer of elevation. Thus, the greater a site’s elevation the greater the potential for error in making the calculation. Hence, the ‘official’ cutoff for pressure records is at just 750 meters elevation. So, in essence, no pressure reading from a site above 750 meters (2460’) is considered accurate enough for the purpose of record keeping or comparison to lower-level sites (for aviation this doesn’t matter since it is just the actual real-time observation for altimeter calibration that is of concern).

Don't ask me why, given the above, why the prior to 1983 event reading from Helena, Montana (see below) was considered 'official' although the reporting site rests at about 1230 meters (3,700') elevation.

U.S. High Barometric Pressure Records

Alaska holds this honor with a reading of 1078.6 mb (31.85”) on January 31, 1989 at Northway during one of the state’s greatest cold waves. Temperatures fell below -70°F at several locations (-76°F at Tanana and -75°F at McGrath). Northway reached -62°F on January 31. Many ‘bush’ aircraft (a principal form of transportation in this region) were grounded in central Alaska since their altimeters were not capable of calibrating to such an extreme pressure reading. That January was the coldest single month on record at Juneau with a 6.8°F average and Nome recorded its coldest temperature on record with -54° on January 27th and 28th.

This high-pressure figure is often erroneously referred to as the highest ever measured in North America. In fact, this is not true since at Dawson City, Yukon, next door to Alaska, but in Canada a higher reading of 1079.6 mb (31.88”) was measured a few days later on February 2, 1989.

In the contiguous United States, the highest-pressure reading yet measured is 1064 mb (31.42”) at Miles City, Montana on December 24, 1983. Many people may remember this as the coldest Christmas in modern U.S. history (at least for almost everywhere east of the Rockies).



Surface weather map for 7 a.m. EST on December 24, 1983 when the highest pressure measured in the contiguous U.S. was recorded at Miles City, Montana. Several locations in Montana recorded temperatures below -50°F including Chester (-52°F), Wisdom (-52°) and Havre (-50°). Chicago temperatures fell to -25° with winds gusting to 41 mph. The lowest wind chill ever measured in the city occurred: -57° (new method of calculation—at the time the wind chill was reported as -82° using the former method of calculation).

The second highest pressure was also recorded in Montana, this time at Helena on January 10, 1962 with a reading of 1063.3 mb (31.40”). The cold wave associated with this event was just as extreme as that of 1989. The January 1962 event is considered the greatest anti-cyclone ever observed in the United Sates although its point maximum is just shy of that of in 1983. Many cities registered their highest-pressure readings during this event.



Weather map for January 10, 1962 at 1 a.m. EST. Note the barometric pressure reading at Helena, Montana at this hour standing at 1062.3 mb. West Yellowstone, Montana reported a temperature of -55° and Eagle Nest, New Mexico fell to -47°. Minneapolis endured 108 consecutive hours below zero during the ensuing cold wave and Galveston Bay at Texas City froze outwards 100 yards from shore. Note the 13° temperature with snow falling at Jackson, Mississippi!...and 22° with snow at Lake Charles, Louisiana on the Gulf Coast!

Here (again, I linked this chart also in my previous blog) are pressure records for selected U.S. cities. You can see that several of the city the high pressure records were set during the 1962 event.

What is the lowest high barometric pressure recording the United States? This would be in Hawaii where the highest reading yet measured has been just 1027 mb (30.32”) at Honolulu (February 10, 1919) and Lihue (January 27, 1955). For the contiguous U.S., it is 1034 mb (30.53”) at San Diego, California back on February 17, 1883.

High Pressure Records Elsewhere in the world

In the United Kingdom the highest pressure yet measured was 1053.6 mb (31.11)” at Aberdeen, Scotland on January 31, 1902.

For Europe the highest reading I am aware of was 1067.1 mb (31.51”) at Parnu, Estonia (at the time part of Russia) on January 22, 1907 and Riga, Latvia the following day.



Isobaric map of Western Europe for January 22, 1907. The isobars are in 5 mb increments. Map courtesy of Stephen Burt.

Australia’s highest pressure on record was 1044.3 mb (30.84”) at Launceston, Tasmania on June7, 1967.

Extreme anti-cyclones are not unique to land masses. Stephen Burt points out that a mid-Atlantic anti-cyclone resulted in a pressure of 1057 mb (31.21”) at a location around 51°N 27°W on January 28, 2003.



Intense anti-cyclones sometimes form over the mid-Atlantic as this map illustrates from January 28, 2003. Chart courtesy of Stephen Burt.

Christopher C. Burt
Weather Historian

KUDOS: Thanks to Stephen Burt for U.K, and European records, Blair Trewin (Australian Bureau of Meteorology) for Australia records, and Randy Cerveny (Arizona State University) for explanation of problem with high-altitude pressure measurements.

REFERENCES: For U.K. and European high-pressure records see The Highest of the Highs: Extremes of Barometric Pressure in the British Isles by Stephen Burt, Weather magazine Vol. 62, No. 2., February 2007.

For Agata, Russia pressure details see Weather and Climate Extremes by Dr. Paul Kraus and Kathleen Flood, U.S. Army Corps of Engineers, TEC-0099 document, p. 52, September 1997.

Barometric Pressure

Updated: 12:49 AM GMT on November 28, 2011

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World and U.S. Lowest Barometric Pressure Records

By: weatherhistorian, 12:03 AM GMT on November 20, 2011

World and U.S. Lowest Barometric Pressure Records

In light of my previous blog on record extra-tropical cyclones, I thought I would follow up with a brief survey of world barometric pressure records (both high and low) in this blog just the low records. Next week I’ll post on the high-pressure records. Recent communication with Stephen Burt, an expert on this subject hailing from the United Kingdom, and Blair Trewin of the Australian Bureau of Meteorology have helped shed some light on this arcane subject.

World Record Minimum Pressure Readings: Tropical Storms

Of course (aside from estimates from tornadoes) the lowest pressures observed on earth have occurred during tropical cyclones, mostly those that have formed in the Western Pacific. The most commonly accepted figure as the world record is that observed during the peak intensity of Super Typhoon Tip when a reading of 870 mb (25.69”) on October 12, 1979 when the storm churned in open waters near the island of Guam. Another contender is an estimate, based on Dvorak intensity, during Cyclone Monica in Australia’s Gulf of Carpentaria. The U.S. Navy Joint Typhoon Warning Center estimated a pressure of 879 mb (25.96”) and perhaps as low as 869 mb (25.66”) based on the Dvorak intensity on April 23, 2006. These figures, however, are not accepted by the Australian Bureau of Meteorology that places a minimum pressure for the storm at 905 mb (26.72”) on the same date and location.

The lowest pressure actually measured in Australia was also 905 mb on the North Rankin A Gas Platform of the coast of Western Australia during Cyclone Orson on April 22, 1989.

Lowest Pressure Readings from Tropical Storms by Ocean Basin

Here is a summary of the lowest barometric pressures measured or estimated to have occurred in tropical storms by ocean basins:



World Record Minimum Pressure Readings: Extra-Tropical Storms

I just blogged on this topic but have received some new information from Stephen Burt and Blair Trewin and so summarize further here:

NORTHERN HEMISPHERE: There are apparently two contenders for the record lowest pressure established in the northern hemisphere. 1) Storm of January 10, 1993 deepened to a central pressure of 912-915 mb (26.93”-27.02”) between Iceland and Scotland near 62°N 15°W and, 2) Storm of December 15-16, 1986 deepened to at least 916 mb south-east of Greenland near 62°N 32°W. A ship in the vicinity actually made a measurement of 920.2 mb on December 15th while still some distance from the center of the storm. The British Meteorological Office assessed the central pressure of the storm at this time as being 916 mb (27.05”) but the West German meteorological service proposed a pressure possibly as low as 912-913 mb (see Stephen Burt article in Weather magazine Vol. 42 pp. 53-56, February 1987).



Surface chart for 0000Z on December 15, 1986 showing the intense cyclone at its deepest southeast of Greenland. The isobars are drawn for every 4 mb. Chart courtesy of Stephen Burt.

SOUTHERN HEMISPHERE: Barometric records for the many intense storms that develop in seas surrounding Antarctica are hard to come by and difficult to assess for accuracy. Blair Trewin of the Australian Bureau of Meteorology relates a value of 919 mb (27.14”) from Casey station on the Windmill Islands (just outside the Antarctic Circle) on Vincennes Bay (66°17’S 110° 31’ E) on August 8-9, 1976. However, this is considerably lower than any other value on record and may very well be an instrument fault although he states “the values are internally consistent with readings below 940 mb from 1600 local time on August 8th to 0700 on August 9th”.

Aside from this remarkable figure the lowest other readings from the region include 934 mb (27.59”) at Halley Bay, Antarctica on Aug. 11, 1994, 942 mb (27.82”) at Grytviken on South Georgia Island (54° 16’S 36° 30’W) sometime between 1929-1964, and 945.1 mb (28.17”) at Campbell Island located about halfway between New Zealand and Antarctica (52°S 69°W) on July 18, 1982.

Some National Low Barometric Pressure Readings
This data is hard to come by for most countries in the world. Here is a potted list (excluding the U.S.A. which I’ll cover separately after this list):





Surface chart of the cyclone that resulted in the lowest barometric pressure ever measured in the United Kingdom; 925.6 mb at Ochtertyre in Scotland on January 26, 1884. Chart courtesy of Stephen Burt.

United States Lowest Barometric Pressure Records

The lowest pressure ever measured anywhere in the United States (either as a result of a tropical or extra-tropical storm) was a reading of 892 mb (26.34”) at Matecumbe Key, Florida during the Great Labor Day Hurricane of September 2, 1935, the most intense hurricane ever to strike the United States. Here is a list of the lowest pressure readings for extra-tropical storms in the United States by region:

ALASKA: 927 mb (27.35”) Dutch Harbor on 10/25/1977

*LOWER 48 STATES: 952 mb (28.10”) Bridgehampton, New York on 3/3/1914

MIDWEST: 955.2 mb (28.21”) Big, Fork, Minnesota on 10/26/2010

OHIO VALLEY: 956 mb (28.23”) Mount Clemens, Michigan 1/26/1978

WEST COAST: 962 mb (28.40”) Quillayute, Washington on 12/1/1987

*This reading is not accepted as official by the NCDC. They post the lowest extra-tropical official pressure readings in the lower 48 states to have occurred on two occasions and places: 955 mb (28.20”) at Nantucket, Massachusetts on March 7, 1932 and also at Canton, New York on January 13, 1913.

Barometric Pressure Records for Select U.S. Cities

For those interested in details of barometric pressure records (high and low) for about 80 U.S. cities click this link to see a Word document with such.

Next week I will cover world and United States record anti-cyclone (high pressure) records. I’m sure you can’t wait.

Christopher C. Burt
Weather Historian

KUDOS: Special thanks to Stephen Burt of the U.K. (see references below) and Blair Trewin of the Australian Bureau of Meteorology.

REF: For details on pressure records of the British Isles see Stephen Burt’s two articles:

“The Lowest of the Lows: Extremes of Pressure in the British Isles” Weather Vol. 62 No.1, Jan 2007 and “The Highest of the Highs” Weather Vol. 62 No.2, Feb. 2007

Barometric Pressure

Updated: 4:08 AM GMT on November 22, 2011

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Super Extra-tropical Storms; Alaska and Extra-tropical Record Low Barometric

By: weatherhistorian, 8:39 PM GMT on November 10, 2011

Super Extra-tropical Storms; Alaska and Extra-tropical Record Low Barometric Pressures

One of the most powerful storms to strike Alaska in recent years has churned across the Bering Sea with hurricane-force winds and sea waves some 40-feet high. See Jeff Masters blog for details on this storm. My blog here is a brief historical re-cap of past storms of similar magnitude (including one just last April in Alaska) and record low pressure readings for extra-tropical storms.



Surface chart of the recent storm at its most intense when it bottomed out at 943 mb (27.85”) late on November 8th local time.

Alaska’s Strongest Extra-tropical Storm on Record: October 25-26, 1977

The most powerful storm, at least in terms of depth of pressure, to affect Alaska in modern history was that of October 25-26, 1977. Dutch Harbor, on the Aleutian Island of Unalaska, recorded a minimum pressure of 926 mb (27.35”) on the evening of October 25th. Winds gusted to 130 mph at Adak, also in the Aleutian Islands. Adak reported a continuous 12-hour period with wind gusts of 110mph+ between 1800Z Oct. 25 and 0600Z Oct. 26. Enhanced infrared radar imagery indicated a closed ‘eye wall’ with this storm. Wave heights of 35 feet on top of swell heights of 60 feet produced significant wave heights of 72 feet according to NWS analysis and ship reports. The analysis speculated that there was the potential for waves as high as 120 feet, although nothing of this magnitude was actually observed. The cyclone had its origins, as is often the case with powerful Alaskan storms, as a West Pacific typhoon.





Hand-drawn weather maps used to be an art! Here are two views of the October 1977 storm; the full version and a detail of the surface analysis for late evening October 25, 1977 when Alaska’s strongest storm in history deepened to 926 mb (27.35”) over Dutch Harbor on the Aleutian Island of Unalaska. Chart drawn by and supplied to me by Steve Gregory who worked with the Ocean Routes Company (now WNI) in Alaska at the time. Steve just sent me this very informative email (in part correcting my mistake in the original post concerning his affiliation with the NWS:

"I didn't work for the NWS, I worked for Oceanroutes (now WNI) when in AK doing site specific forecasts for 7 exploratory drilling rigs located about 6 miles offshore of Cape Yagataga along the south central coast.  That location was something else.  When I first started, I worked as an observer on one of the rigs (2 weeks on, 2 weeks off) and when storm systems approached, winds would increase to about 3 times what one would normally expect based on the observed pressure gradient, and winds were always out of the East, perpendicular to the isobars.  No one really knew why - but we suspected it had to do with a glacier located just to our northeast.  A rough rule of thumb was to use the pressure difference between Yakatut and Middleton Island - with every millibar difference equal to 5 Kts.  60Kt winds were very common - averaging 1 or 2 times /week on average.  You haven't lived until you've been out on the ocean with 80mph winds and 30 foot waves.
 
One final comment.  You will find that storms with NWS analyzed pressures of 948mb (or lower) occur quite frequently in the Gulf of Alaska.  Must average at least 5 such storms every year, with 1 or 2 of them getting into the 930's.  But these mega-storms attract little attention because there is no major affect on any populated areas (although aircraft landing in ANC can experience true, severe turbulence on approach through Turnagain Arm.  I've never really had the time to check, but I suspect a careful analysis would show pressures in the 920's."


Other Powerful Alaskan Storms

The highest wind gust yet measured in Alaska was 159 mph at the isolated settlement of Attu on December 7, 1950. Attu is located on the westernmost Aleutian Island of the same name, some 1000 miles west of Anchorage.

The state’s highest sustained one-minute wind speed of 93 mph was recorded at Kotzebue during a storm on February 25, 1951.

Although the current storm has received quite a bit of publicity, its minimum pressure of 943 mb is still shy of the strongest storm so far observed this year which swept over the Aleutian Islands and into the Bering Sea on April 6th with a minimum pressure of 939 mb (27.73”). Cold Bay reported a maximum wind gust of 91 mph.



Surface map of the April 7, 2011 storm that although stronger than the recent November storm (939 mb vs. 943 mb) was less destructive since it shied further away from the Bering Sea Alaskan coastline.

In October 2004 and again in September 2005 two large storms with central pressures of 941mb produced a storm surge of almost 10.45 feet at Nome beaching boats and damaging the town’s waterfront where an unofficial wind gust of 83mph was recorded. The ferocity of both storms led then NWS Fairbanks’s Office Lead Fore caster, Rick Thoman, to comment, “Storms that affect Alaska are far, far bigger than hurricanes. Hurricanes are tiny compared to great storms that take up a quarter of the Bering Sea.” REF: Alaska Science Forum Article #1774: ‘No Hurricanes in Alaska but…’ by Ned Rozell, October 27, 2005.



A ten-foot storm surge deposited boats along the shoreline of Nome’s Snake River in September 2005. Nome’s greatest storm surge occurred during a storm in November 1974 when waters rose 13 feet above normal. Photo by Ned Rozell.

Cause of Alaskan Super Storms

The reason for the amazing intensity of some of the extra-tropical storms that swipe the Aleutians and the Bering Sea is that the low-pressure centers tap into relatively mild, moist sub-topical air off the coasts of Japan (sometimes the remnants of typhoons) and cold dry air centered over Eastern Siberia; somewhat in the same fashion that low pressure systems sometime ‘bomb out’ along the Eastern Seaboard of the United States after entraining, in their case, Gulf Stream moisture and Canadian cold, dry air.

Comparison to Atlantic Extra-tropical Storms

Amazing as the pressure readings observed during some Alaskan super storms, they still cannot quite compare (yet!) to the strongest low-pressure storms that form during the winter months in the North Atlantic.

In January 1993 a series of intense low-pressure systems passed near Scotland’s Shetland Islands and over the North Sea. On January 5th one such storm caused the super oil tanker Braer to be blown onto a rocky shoal on one the Shetland Islands. A stronger storm on January 10-11th caused the ship to break apart and release its contents resulting in a massive oil spill.



The oil tanker ‘Braer’ founders on the rocky shoreline of the Shetland Islands on January 5, 1993. Photographer unknown.

The storm that caused the Braer to break up had a central pressure of 913 mb (26.96”), the lowest sea-level adjusted barometric pressure ever observed on the earth’s surface, aside from tropical storms and tornadoes of course.



An infrared satellite image of the North Atlantic Storm of January 11, 1993 at 0600Z when it deepened into the strongest extra-tropical cyclone ever observed on earth with a central pressure of 913 mb (26.96”). Satellite image from EUMETSAT Meteosat-4.

Other Atlantic storms have also recorded barometric pressures lower than the Dutch Harbor figure, including 920.2 mb (27.17”) by the ship Uyir while she sailed southeast of Greenland on December 15, 1986. The British Met. Office calculated that the central pressure of the storm, which was centered some distance southeast of the ship, was 916 mb (27.05”). British weather historian, Stephen Burt has also made note of other remarkable low-pressure readings from the North Atlantic:

921.1 mb (27.20”) on Feb. 5, 1870 measured by the ship Neier at 49°N 26°W (another ship in the area measured 925.5 mb)

924 mb (27.28”) on Feb. 4, 1824 at Reykjavik, Iceland (the lowest on land measured pressure in the North Atlantic)

925.5 mb (27.33”) on Dec. 4, 1929 by the SS Westpool somewhere in the Atlantic (exact location unknown)

925.6 mb (27.33”) on Jan. 26, 1884 at Ochtertyre, Perthshire, U.K. (the lowest pressure recorded on land in the U.K.)

For comparison’s sake, the lowest pressure measured on land during an extra-tropical storm in the United States (aside from Alaska) was 952 mb 28.10” at Bridgehampton, New York (Long Island) on March 1 during, the Great Billy Sunday Snowstorm.

On the West Coast the lowest pressure measured on land was 962 mb (28.40”) at Quillayute, Washington on December 1, 1987. However, a ship near the mouth of the Umpqua River in Oregon measured a pressure of 955 mb (28.20”) during the Great Storm King of Jan.9, 1880.

KUDOS: Thanks to Steve Gregory for the map of the Alaskan storm of 1977 and related information. Thanks also to Stephen Burt for list of North Atlantic pressure records.

Christopher C. Burt
Weather Historian

Updated: 10:21 PM GMT on November 14, 2011

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October 2011 Global Weather Extremes Summary

By: weatherhistorian, 8:16 PM GMT on November 05, 2011

October 2011 Global Weather Extremes Summary

October was a relatively calm month so far as global weather extremes were concerned. The biggest story for the United States was the unprecedented snowstorm that struck the mid-Atlantic and Northeast on October 29-30th. Unusual warmth occurred in Europe at the beginning of the month and in southern Africa towards the end of the month. Extreme flooding affected Central America, Italy, and Southeast Asia.

Below are some of the month’s highlights.

NORTH AMERICA

The most intense October snowstorm on record left between 22 and 27 dead and 2.5 million without electricity from Virginia to Maine when a classic northeaster cyclone moved up the Atlantic Coast on October 29th and 30th. As of this writing, a week later, some 800,000 are still without power in Connecticut and Massachusetts. Amazing snow totals of over two feet affected the hardest hit portions of Massachusetts and New Hampshire (see Jeff Masters and my blog of Oct. 30). At the peak of the storm on Saturday evening, Windsor, Massachusetts received 26.0” of snow in just a six-hour period.



Unisys surface analysis map for 8 p.m. EST October 29th, around the time when the snow was falling at its heaviest in southern New England.

Concord, New Hampshire had 22.2” in a 15-hour period between 4pm Oct. 29 and 7am October 30. This was the 2nd greatest 24-hour snowfall on record for this city that has experienced many formidable snowstorms since records began there in 1871 (the record 24-hour snowfall was 25” during the famous blizzard of December 26-27, 1969).



Heavy wet snow toppled trees onto parked cars in Worcester, Massachusetts. The storm has become the 14th billion-dollar natural disaster in the U.S.A. so far this year. Photo by Adam Hunger/AP.

In spite of some significant rainfall during the month, portions of western Texas and the Texas Panhandle experienced several intense dust storms reminiscent of the 1930s ‘Dust Bowl’ era. Amarillo, and Lubbock, Texas as well as Dodge City, Kansas remained on track for their driest calendar year on record. In contrast, much of Ohio and Pennsylvania have already achieved their wettest year on record. As of Nov. 1st Williamsport, Pennsylvania has recorded 63.18” (old record 61.27” in 1972), Scranton 54.02” (old record 53.71” in 1945), Harrisburg has recorded 67.59” (old record 59.67” in 1863), Cleveland, Ohio has measured 55.81”(old record 53.83” in 1990), and Binghamton, New York 61.86” (old record 49.33” in 2006).

Hurricane Jova roared ashore on Mexico’s west coast between Manzanillo and Puerto Vallarta on October 12th with 100mph wind gusts and killing five.



An amazing nighttime video capture of Hurricane Jova’s winds as the storm came ashore north of Manzanillo, Mexico on October 12th. Photo/video taken by wunderground blogger Mike Theiss at Tenacatita, Mexico.

The coldest temperature measured in the northern hemisphere during October was -61.4°F (-51.9°C) at Summit, Greenland.

SOUTH AMERICA and CENTRAL AMERICA

Extreme flooding in El Salvador and Guatemala resulted in the deaths of at least 105 people the week of October 13-20. It was one of the worst natural disasters in recent history for El Salvador. One location, Huizucar, in El Salvador recorded an astonishing 59.57” (1513mm) of precipitation in the ten-day period of October 10-20.



Map of precipitation totals across El Salvador the period of October 10-20. El Salvadoran National Hydrological Service.

Winds of 75mph in mid-October whipped up fallen volcanic ash (that had accumulated as the result of the eruption of Chile’s Puyehue volcano) closing airports in Argentina and Uruguay.

EUROPE

The United Kingdom recorded its warmest October temperature on record when a reading of 85.8°F (29.9°C) was observed at Gravesend, Kent on October 1st. This surpassed the previous warmest October temperature of 84.9°F (29.4°C) set at Cambridgeshire on October 1, 1985. Wales also broke its warmest October day on record with an 82.8°F (28.2°C) reading at Hawarden, Flintshire on October 1st (previous record was 79.5°F (26.4°C) at Ruthin, Denbighshire on October 1, 1985). Stephen Burt writes me, "At least as noteworthy was the fact that 1 October became the hottest day of the year quite widely in central southern England and in western and northern England. In central southern England, within the last 100 years, the hottest day of the year has never occurred later than 8 September." The month was the 8th warmest October on record for the U.K. since 1910.

Dublin, Ireland, reported 82.2mm of rainfall in 24 hours on October 24th, its wettest October day since 1954. Two people died in flooding as a result. The coldest temperature measured in the U.K. during October was -3.3°C at Santon Downham, Suffolk on October 20th. The highest wind gust measured was 77mph at Killowen, County Down on October 17th.

Incredible flash flooding struck much of Italy on October 26th killing at least nine and devastating towns in the Liguria region near Genoa and also in central Tuscany. An amazing 450mm (17.72”) of rain fell in just four hours at Quezzi, Liguria. The torrential rains also affected extreme southeastern France where up to 600mm (23.62”) of rain in 12 hours were reported.



A flooded street in Genoa during the intense rainfall of October 26th. Photo by Luca Zennaro/EPA

AFRICA

An extreme heat wave affected Botswana, Zimbabwe, and Zambia during the last week of October. All-time absolute maximum temperatures were recorded in Harare (98.1°F/36.7°C) and Bulawayo (101.3°F/38.5°C), Zimbabwe; Livingston (106.3°F/41.3°C), Zambia; and Francistown, Botswana where the 107.8°F (42.1°C) was just shy of the national record for Botswana of 108.3°F (42.4°C) recorded at Gomo in January 1932.

The hottest temperature observed was 112.3°F (44.6°C) at Buffalo Range, Zimbabwe on October 25th. This was also the warmest temperature observed in the southern hemisphere during October.

ASIA

The big story in Asia during October was (and still is!) the flooding in Thailand where Bangkok remains submerged as of this writing and the situation seems to be getting worse as flood waters continue their march toward the heart of the city. For details on the Bangkok flood see my previous blog. Some 507 people have died in Thailand so far as a result of the floods.

In Burma (Myanmar), over 100 people died in the city of Pakokku, which rests on the banks of the Irrawaddy River in central Burma, on October 21-22 when a flash flood swept away 2000 homes in Pakokku and four other towns in the Magwe Division.



The main bridge of Pakokku, Burma (Myanmar) swept away by floodwaters on October 22nd. Photo taken by unidentified resident of Pakokku.

Heavy rains also pelted the South China island province of Hainan in early October as the result the passage of Tropical Storm Nalgae. The city of Haikou apparently recorded 13.13” (333.6mm) of rain in 24 hours and 20.35” (517mm) in 48 hours, the greatest accumulations on record for the site.

The warmest temperature in the northern hemisphere and the world during October was 113.7°F (45.4°C) measured at Mecca, Saudi Arabia on October 1st.

AUSTRALIA

Temperatures were close to normal in most of Australia during October and precipitation was considerably above normal (152% of normal nation-wide to be precise) making this the 17th wettest October in over 112 years of record.

The normally wet top station of Bellenden Ker, Queensland measured 58.82” (1494mm) of precipitation during the month, the highest such figure ever measured during October at any site in Australia. 17.32” (440mm) of this total fell on the singe day of Oct. 19th, the 2nd greatest calendar day measurement for October in Australian history (record is 21.70”/551.2mm at Pacific Heights, Queensland on Oct. 8, 1914).



Map of rainfall deciles for October, 2011. It was the 3rd wettest October on record for Western Australia. Map courtesy of the Australian Bureau of Meteorology.

The warmest temperature measured during the month was 111.2°F (44.0°C) at Wyndham Aero, Western Australia on October 12th. The coldest temperature was 18.0°F (-7.8°C) at Thredbo, New South Wales on October 3rd.

ANTARCTICA

The coldest temperature in the southern hemisphere and the world during October was -98.5°F (-72.5°C) recorded at Dome Fuji on Oct. 14th.

KUDOS Thanks to Maximiliano Herrera for global temperature extremes data and Stephen Burt for the U.K. extremes.

Christopher C. Burt
Weather Historian

Extreme Weather

Updated: 5:59 AM GMT on November 08, 2011

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About weatherhistorian

Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.