Saturday, August 8, 2009

Felicia Continues to Weaken in Central Pacific, On Track for Hawaii


Images (click to enlarge): Hurricane Felicia visible satellite image from Weather Underground; Track forecast from National Hurricane Center

11 am HST Update: The Central Pacific Hurricane Center in Honolulu reports that aircraft reconnaissance data indicate a slight weakening of maximum winds to 85 mph. Movement is still westward at 15 mph from a position 845 miles east of Hilo or 1025 miles east of Honolulu. A Tropical Storm Watch could be required for portions of Hawaii later today or tonight.
...SUMMARY OF 1100 AM HST INFORMATION...
LOCATION...19.8N 142.1W
MAXIMUM SUSTAINED WINDS...85 MPH
PRESENT MOVEMENT...WEST OR 280 DEGREES AT 15 MPH
MINIMUM CENTRAL PRESSURE...981 MB
Original post:
After weakening to Category 2 on Friday, Hurricane Felicia has continued weakening to Category 1 by Saturday morning. At 8 am PDT, the storm had maximum winds of 90 mph as it moved westward at 15 mph from a position 930 miles east of Hilo, Hawaii. The current track is expected to continue for the next several days along with gradual weakening.

Interests in Hawaii are advised to monitor the progress of the storm. The National Weather Service in Honolulu has issued a flood potential outlook for the state:
THE LATEST FORECAST FROM THE NATIONAL HURRICANE CENTER INDICATES
THAT HURRICANE FELICIA WILL WEAKEN TO A TROPICAL STORM OR
DEPRESSION NEAR THE HAWAIIAN ISLANDS. REGARDLESS OF ITS
INTENSITY...FELICIA COULD PRODUCE VERY HEAVY RAINFALL WITH
POSSIBLE FLASH FLOODING. RAIN BANDS MAY REACH THE BIG ISLAND
EARLY ON MONDAY WITH HEAVY RAINFALL POTENTIALLY SPREADING WESTWARD
ACROSS THE STATE THROUGH TUESDAY.
The Honolulu Advertiser and Star-Bulletin report that sales of emergency supplies have been brisk across the state, and government officials are preparing plans to deal with possible storm impacts.

Friday, August 7, 2009

PM Update: U.S. Has 27th Coolest July

For Washington, DC July temperature analysis, see:
Washington Has 44th Coolest July
For previous record temperature posts, see:
Record Heat
Record Cold


The National Climatic Data Center's (NCDC) preliminary analysis for July, posted this afternoon, indicates that the past month was the 27th coolest out of 115 years of record in the U.S. The national average temperature of 73.5°F was 0.8°F below the 20th century average. For the year to date (January through July), on the other hand, the average was the 28th warmest.

The cool temperatures were particularly acute in the Midwest and Ohio Valley, where 6 states had their coolest July on record: Iowa, Illinois, Indiana, Ohio, Pennsylvania, and West Virginia. In addition, several adjoining states had their second coolest July: Wisconsin, Michigan, Missouri, and Kentucky.

Temperatures were above normal from Florida westward across the Southwest, California, and the Pacific Northwest. Arizona had its third warmest July, and temperatures were also much above normal in New Mexico and Washington. NCDC reports that "Death Valley, California set its all-time monthly average maximum temperature of 121.3°F. Twenty-two days in Death Valley reached 120°F or higher which beat the old record of 19 days."

The temperature pattern of cold in the Midwest and Northeast and warm in the West was the result of a persistent, abnormally strong, circulation pattern in the middle levels of the atmosphere which had a low pressure trough centered near the Great Lakes and a high pressure ridge along the Pacific Coast.

Other temperature highlights from NCDC:
  • "The U.S. had not seen a single record cold state, in any month, since August 2004 and there had not been six or more record cold states in a month since July 1992, when there were nine."
  • "More than 400 record low minimum temperatures and 1,300 record low maximum temperatures (lowest high temperature) were set during July across the nine-state area that makes up the Central region."

Images (click to enlarge): July 2009 temperature departure from average, statewide temperature rank, 500 mb heights and departures from average, from NOAA/NCDC

Thursday, August 6, 2009

Category 4 Hurricane on Track to Hawaii
Major Weakening Expected Before Possible Landfall

8 pm PDT Update: Felicia remains at 135 mph at 8 pm. Movement is toward the west-northwest at 12 mph.

PM Update: As of 2 pm PDT, Felicia has weakened slightly to 135 mph. The storm is moving northwest at 10 mph from a position a little under 1500 miles east of Hilo, Hawaii.

Original post:
Despite the slow start to the Atlantic tropical season, the Eastern Pacific has now had 6 named storms. The latest, Hurricane Felicia, has reached major status at Category 4, with maximum winds of 140 mph. Its westward track is likely to bring it to the vicinity of the Hawaiian Islands, but it's likely to undergo serious weakening on the way because of several factors:
  • cooler water temperatures
  • increased wind shear in the form of strong westerly winds aloft
  • drier air
The latest advisory calls for the storm to begin weakening later today. As weakening continues in the next several days, it is forecast to approach Hawaii as a weak tropical storm or tropical depression. The current wind speed outlook calls for a 5-10% chance of tropical storm force winds reaching the Big Island within the next 5 days. CNN quotes Richard Knabb, deputy director of the Central Pacific Hurricane Center: "If anything, it will be a rain-making system over the (Hawaiian) islands."

Images (click to enlarge): Hurricane Felicia infrared satellite image from Weather Underground and forecast track from National Hurricane Center

Hurricane Season Outlook Revised Lower

NOAA this morning revised its Atlantic tropical season outlook downward from the forecast released in May. The new prediction from the Climate Prediction Center and National Hurricane Center calls for the following probabilities (May numbers in parentheses):
Above normal: 10% (25%) 
Near normal: 50% (50%)
Below normal: 40% (25%)
There is a 70% chance of the following numbers of storms (normal in parentheses):
Named storms:     7-11 (11)
Hurricanes: 3-6 (6)
Major hurricanes: 1-2 (2)
The intensity of the hurricane season is measured using the Accumulated Cyclone Energy (ACE), which is a combination of the duration and intensity of storms, rather than simply the number of storms.

The downward revision in the forecast is based mainly on the continued development of El Niño conditions in the tropical Pacific. The higher wind shear (increase of wind with height) from El Niño is expected to outweigh the effects of warmer than average Atlantic and Caribbean sea surface temperatures.

Despite the indications of lower than average tropical activity, NOAA cautions residents of the Atlantic and Gulf Coasts that they should be prepared every year, regardless of the overall level of activity. To paraphrase on old mariners' saying, "One nasty hurricane can spoil your whole day." Some examples of hurricane landfalls in El Niño years include Betsy (1965), Bob (1991), Danny (1997), and Lili (2002). The most notorious example of a disastrous storm during a below-average season was Andrew (1992). Others include Hurricane Donna (1960) and Hurricane Betsy (1965).

The latest dates for the first storm of the season are:
For records back to 1851:
Tropical storm: September 15 (1914)
Hurricane: October 8 (1905)

Satellite era (since 1966):
Tropical storm: August 30 (Arlene, 1967)
Hurricane: September 11 (Gustav, 2002)

Image (click to enlarge): Recent sea surface temperatures, from NOAA/Climate Prediction Center

Wednesday, August 5, 2009

Washington Has 44th Coolest July


For more posts on Washington, DC temperature and precipitation, see:
Washington DC Weather Records


Image (click to enlarge): Washington, DC July 2009 temperature; CapitalClimate chart from National Weather Service data

After starting the month in near record cool territory, Washington, DC ended July with an average temperature only 2.3° below the long term average. This was the coolest since the back-to-back cool years of 2000 and 2001. The month is tied for 44th coolest July since official records began in 1871.

After the coolest day on July 5, with a high of only 73° and an average of 9° below normal, temperatures rose steadily during the month. The 90° level was first reached on July 12, and there were 7 90°+ days in all, including the month's high of 96°. This was just half of the long-term average of 13.8 days in July, but the high was only a little short of the average monthly high of 96.8°.

Despite the deficiency of precipitation, there were 0 clear days and 24 partly cloudy, compared with the average of 7 and 12, respectively.

Record July Cold in Madison, Wisconsin

For previous record temperature posts, see:
Record Heat
Record Cold


The National Weather Service reports that July was the coldest on record at Madison, Wisconsin. It was also a very dry month in the state:
The average temperature at Truax Field in Madison for July 2009 was a record 65.7 degrees or 5.9 degrees below normal. The previous record was 66.7 degrees in 1891. Records go back to 1869. It was also a dry month with 1.94" of rainfall. This makes July 2009 the 7th driest on record for Madison. The driest July was in 1909 when only 0.29" of rain fell.

The average temperature at Mitchell Field in Milwaukee for July 2009 was 68.6 degrees or 3.5 degrees below normal. This is not cool enough to be in the top 10 coolest on record. However, it was dry and the 0.71" of rain that fell during July 2009 at Mitchell was the 4th driest on record. The driest July was in 1936 when only 0.28" of rain fell.
Image (click to enlarge): Daily temperatures, May-July, 2009, at Madison, Wisconsin, from National Weather Service

Coolest July on Record in Central and Northern Illinois

For previous record temperature posts, see:
Record Heat
Record Cold


The National Weather Service (NWS) reports that July 2009 was the coolest on record at Peoria and Lincoln, Illinois, and the second coolest at Springfield and Champaign:
In Peoria, the average temperature during the month was 70.7 degrees, which was 4.4 degrees below normal. This was the coolest July on record in Peoria, breaking the old record of 71.2 degrees set in 1971. Daily record cool highs were set on the 1st (69 degrees), 18th (71), and 19th (73).

The average temperature for Lincoln was 69.4 degrees, which was 5.6 degrees below normal. This was the coolest July on record, breaking the record of 71.3 degrees in 1924. Record cool highs were set on July 1 (70), July 17 (72), and July 18 (71). Lincoln tied a record low of 49 degrees on the 20th.

In Springfield, the average temperature was 71.2 degrees, which was 5.1 degrees below normal. It was the 2nd coolest July on record, surpassed only by a 71.0 degree average in 1891. A daily record cool high was set on July 18th (71), while Springfield set a record low of 52 degrees on the 20th.

Through July 30th, the average temperature for Champaign is 70.5 degrees (4.5 degrees below normal) and ranked as the 2nd coolest July on record. Daily record low highs were set on July 4 (67) and July 18 (73).

It is interesting to note that no 90 degree high temperatures were reached at these sites in July. This only happened in one other year, 2000. The warmest day at Peoria was 87 (15th) and the warmest day in Lincoln and Springfield was 86, both on the 7th. The coldest July monthly maximum temperature since 1948 was 88 in Peoria and Springfield, and 89 in Lincoln, all set in 2000. Champaign's highest temperature was 87 degrees (28th), Decatur was 86 (28th), Mattoon 87 (7th), Lawrenceville 88 (7th), and Bloomington 86 (15th). Central and southeast Illinois averages around a dozen 90+ degree high temperatures in a typical July.
The NWS also reports a record cold July in Rockford and a near-record in Chicago:
Rockford had the coldest July ever on record, running 2F colder than the previous coldest July on record.

In Chicago, July 2009 will go down as the 7th coldest July on record. However...in 1942 the official recording station was moved away from the lakefront. If we look at temperature data from 1942 to present...the July 2009 average temperature of 69.4 would rank second coldest. The coldest July on record since 1942 was 69.3 degrees set back in 1992.
Image (click to enlarge): July monthly maximum temperature by year in Peoria, from National Weather Service

Arctic Ice Melt Continues Near Record Rate in July

See here for other posts on Polar Climate.

The National Snow and Ice Data Center (NSIDC) reported yesterday that the average rate of Arctic ice melt in July was nearly equal to that in the record-breaking year of 2007. Total ice extent for the month was the third lowest for the satellite record in July, following behind 2007 and 2006.

A strong area of high pressure over the western Arctic brought warm temperatures and clear skies to the region, helping to promote the melting process. (The same high pressure ridge brought record breaking high temperatures to much of the western U.S. from Arizona through Oregon and Washington and into Alaska.)

The NSIDC overview stated:
Sea ice extent averaged over the month of July 2009 was 8.81 million square kilometers (3.40 million square miles). This was 680,000 square kilometers (263,000 square miles) above the record low that occurred in July 2007, 250,000 square kilometers (97,000 square miles) below July 2008, and 1.29 million square kilometers (498,000 square miles) below the 1979 to 2000 average. Sea ice extent is unusually low in the Kara Sea, Baffin Bay, and along the Russian coast. The only area with significant above-average ice extent is southern Hudson Bay.
Image (click to enlarge): Arctic sea ice extent as of August 4 from NSIDC

Monday, August 3, 2009

Attention Duke Searcher!
And Attention Other Climate Data Searchers

Attention user searching from duke.edu: Even though we seldom agree with anything published by the Pielkes, as a public service, here's the reference you've been searching for in Google several times today (most recently at 9:03 pm):
Nicola Scafetta Comments on “Solar Trends And Global Warming” by Benestad and Schmidt

Attention any other searchers for climate data and/or information:
Google is an excellent tool, and the Googling Monkeys here at the Climate Capitol have been using it since well before there was a CapitalClimate. However, sometimes it can be a little frustrating to click on a search result and not get what you're really looking for. If that's the case when you end up here, please ask your climate data question as a comment to this post, and we'll do our best to find you the answer, or point you to a possible source if we can't find it.

To kick things off, here's a question via Yahoo search from Kennewick, Washington:
"what is the all time record high temperature in wenatchee wa" 
Sorry you couldn't find the answer directly when you came to the site a little while ago, but here's some data from the National Weather Service based on the last 50 years (apparently the full period of official records there):
Highest Daily Maximum Temperature (degrees F)
Days: 1/1 - 12/31
Length of period: 1 day
Years: 1959-2009

Rank Value Ending Date
1 109.0 8/4/1961
2 108.0 7/27/1998
3 107.0 8/1/2009, 7/23/2006, 7/22/1994, 7/19/1979, 8/3/1961
8 106.0 7/26/1998, 7/18/1960
10 105.0 7/28/1998

Portland Extends All-Time Record Heat Wave Another Day


Image (click to enlarge): Portland, Oregon temperature, dewpoint, and relative humidity, for 24 hours ending 5 pm PDT, August 3, from National Weather Service

For previous record temperature posts, see:
Record Heat
Record Cold


Aug. 4 Update: The record streak was broken on Tuesday with a high of 85°.

9 pm PDT Update: The National Weather Service record report:
...NEW RECORD FOR CONSECUTIVE DAYS WITH TEMPERATURES AT OR ABOVE 90   
DEGREES IN PORTLAND...

THE HIGH TEMPERATURE AT PORTLAND AIRPORT ON MONDAY WAS 91 DEGREES.
THIS MARKS THE 10TH CONSECUTIVE DAY THAT PORTLANDS TEMPERATURE
REACHED 90 DEGREES OR ABOVE. THIS BREAKS THE PREVIOUS RECORD -
INCIDENTALLY SET YESTERDAY - AND THE OLD RECORD WHICH WAS AN 8-DAY
STREAK BETWEEN AUGUST 12-19 1967.
Original post:
After expecting a possible break in the record streak of 90°+ days, Portland, Oregon reached a high of 90° at 5 pm, extending the new record to an unprecedented 10th day.

Here's the National Weather Service summary for the previous 9 days:
HIGH TEMPERATURES AT PORTLAND AIRPORT DURING THE PAST NINE DAYS...  

DAY/DATE HIGH TEMPERATURE
=======================================
1. SAT JUL 25 2009 90
2. SUN JUL 26 2009 93
3. MON JUL 27 2009 103 *
4. TUE JUL 28 2009 106 *
5. WED JUL 29 2009 106 *
6. THU JUL 30 2009 96
7. FRI JUL 31 2009 94
8. SAT AUG 1 2009 95 *
9. SUN AUG 2 2009 94

* DENOTES HIGH TEMPERATURE SET NEW RECORD FOR THE DATE.

All-Time Monthly Heat Records Set in Arizona

For previous record temperature posts, see:
Record Heat
Record Cold


The National Weather Service reports that July 2009 was the hottest month ever recorded in Phoenix and Yuma, Arizona:
With July 2009 now over it will go down as not only the hottest July on record but the hottest month of all-time in both Phoenix and Yuma (as determined by average temperature, see tables below). The data below represent the top ten warmest Julys for Phoenix and Yuma by average high, mean, and low temperatures. Records for Phoenix began in 1896 and for Yuma in 1878.
Phoenix, AZ
Top 10 Hottest Julys
Rank Average Max Average Average Min
Temperature (°F) Temperature (°F) Temperature (°F)
1 109.8 1989 98.3 2009 87.1 2009
2 109.5 2009 97.6 2003 86.6 2003
3 109.5 2005 97.4 1989 86.4 2006
4 108.7 2003 97.2 2005 85.0 2005
5 108.3 1978 96.5 2006 85.0 1989
6 108.1 1979 96.1 1988 84.8 2007
7 107.6 1980 96.0 2002 84.8 2002
8 107.5 1988 95.8 2007 84.8 1988
9 107.5 1933 95.6 1980 84.8 1981
10 107.5 1931 95.5 1983 84.2 1996

Yuma, AZ
Top 10 Hottest Julys
Rank Average Max Average Average Min
Temperature (°F) Temperature (°F) Temperature (°F)
1 110.8 1957 97.5 2009 86.0 2006
2 110.4 1989 97.2 2006 85.0 2009
3 110.3 1942 96.7 1959 84.5 1996
4 110.2 1960 96.4 1996 83.9 1959
5 110.0 2009 96.3 1989 83.6 1998
6 109.7 1994 96.3 1957 83.3 2003
7 109.5 1878 96.0 1998 83.0 2005
8 109.4 1959 95.7 2005 83.0 2002
9 109.3 1951 95.7 1994 82.8 2007
10 109.2 1958 95.7 1960 82.8 1990

Sunday, August 2, 2009

Portland Breaks All-Time Heat Wave Record
90 Degrees Plus for 9th Consecutive Day



Images (click to enlarge): Temperature at 5 pm PDT, August 2, from Unisys; Portland, Oregon temperature, dewpoint, and relative humidity, July 23-Aug. 2, from National Weather Service

For previous record temperature posts, see:
Record Heat
Record Cold


By 4 pm PDT today, the temperature at Portland, Oregon had reached 91°. The high as of 5 pm was 93°, and at 6 pm, the reading had climbed again to 94°. This is the 9th consecutive day that Portland has reached or exceeded 90°, an all-time record. The previous record of 8 days was set August 12-19, 1967. The record streak is forecast to end tomorrow with a high of 85°. Yesterday's high was also a record for August 1:
PORTLAND BROKE THEIR DAILY HIGH TEMPERATURE RECORD FOR AUGUST 1 ON 
SATURDAY...WITH A HIGH TEMPERATURE OF 95 DEGREES. THE PREVIOUS HIGH
TEMPERATURE RECORD FOR AUGUST 1 IN PORTLAND WAS 93 DEGREES...SET
BACK IN 1986.
Although the peak of the heat wave last week fell 1° short of the all-time record high, several records for daily average temperature were set. The month of July overall was also the second hottest month ever in Portland:

WHILE PORTLAND FELL JUST SHY OF THE ALL-TIME HOTTEST MAXIMUM
TEMPERATURE ON RECORD OF 107 DEGREES JULY 28TH AND JULY 29TH...
THEY DID EXPERIENCE THE HOTTEST TWO FULL CALENDAR DAYS ON RECORD.
THE DAILY AVERAGE TEMPERATURES ON THESE DAYS WERE WARMER THAN ANY
DAILY AVERAGE TEMPERATURE ON RECORD...DATING BACK TO 1926. THE DAILY
AVERAGE TEMPERATURE IS THE MEAN OF THE MAXIMUM AND MINIMUM
TEMPERATURE FOR A PARTICULAR CALENDAR DAY. THE UNUSUALLY WARM NIGHTS
IN THE LOWER TO MID 70S HELPED PUT PORTLAND OVER THE TOP IN THIS
CATEGORY.

THE NEW TOP 10 HOTTEST DAILY AVERAGE TEMPERATURES FOR PORTLAND ARE...

1. 90 DEGREES - JUL 28 2009 .... NEW ....
2. 89 DEGREES - JUL 29 2009 .... NEW ....
3. 87 DEGREES - JUL 17 1941
4(T). 86 DEGREES - JUL 27 2009 .... NEW ....
4(T). 86 DEGREES - JUL 28 1998
4(T). 86 DEGREES - JUL 27 1998
4(T). 86 DEGREES - AUG 9 1981
4(T). 86 DEGREES - AUG 8 1981
4(T). 86 DEGREES - AUG 17 1977
4(T). 86 DEGREES - JUL 16 1941

(T) DENOTES A TIE

SINCE THREE OF THE TOP FOUR HOTTEST AVERAGE DAILY TEMPERATURES WERE
SET DURING THE 2009 HEAT WAVE OF JULY 27-29...THIS EASILY MAKES IT
THE HOTTEST 3-DAY PERIOD IN PORTLAND HISTORY...DATING BACK TO 1926.

THE NEW TOP 4 HOTTEST 3-DAY PERIODS IN PORTLAND HISTORY ARE...

1. 88.0 DEGREES - JUL 27-29 2009
2. 86.7 DEGREES - JUL 28-30 2009
3. 85.7 DEGREES - JUL 15-17 1941
4. 85.3 DEGREES - AUG 8-10 1981

JULY 2009 GOES DOWN IN THE BOOKS AS THE SECOND HOTTEST MONTH ON
RECORD FOR PORTLAND...DATING BACK TO 1926. THE AVERAGE TEMPERATURE
FOR THE MONTH OF JULY 2009 WAS 73.6 DEGREES. THE EXISTING RECORD
HOTTEST JULY IS 74.1 DEGREES...SET BACK IN 1985...WHICH ALSO STANDS
AS THE HOTTEST AVERAGE TEMPERATURE FOR ANY MONTH ON RECORD FOR
PORTLAND.

HOTTEST MONTHS ON RECORD FOR PORTLAND
=============================================
1. 74.1 DEGREES - JULY 1985
2. 73.6 DEGREES - JULY 2009 .... NEW ....
3. 72.9 DEGREES - AUGUST 1967
4. 72.3 DEGREES - AUGUST 1986
5. 72.1 DEGREES - AUGUST 1981


JULY 2009 ALSO TIES FOR THE FOURTH HOTTEST MONTH ON RECORD FOR
SALEM...DATING BACK TO 1892.

HOTTEST MONTHS ON RECORD FOR SALEM
=============================================
1(T). 72.0 DEGREES - JULY 1941
1(T). 72.0 DEGREES - JULY 1906
3. 71.6 DEGREES - AUGUST 1967
4(T). 71.2 DEGREES - JULY 2009 ... NEW ...
4(T). 71.2 DEGREES - JULY 1958

Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.