WunderBlog Archive » Category 6™
Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.A Sizzling October Sunday for Northern Plains
Sweaters and jackets lay dormant, replaced by T-shirts and shorts, for many residents of the United States over the weekend. Temperatures soared into the 80s and 90s across many parts of the country west of the Mississippi River. It wasn’t exactly chilly across the eastern U.S., either, with sunshine and pleasant 60s and 70s the rule over most areas. The most impressive extremes occurred on Sunday over the Northern Plains, where an already-warm airmass from the Rockies warmed even further as west winds pushed it downslope.
Figure 1. High temperatures observed on Sunday, October 11, 2015. Image credit: The Weather Channel.
Even though we’re now into mid-October, when average temperatures are falling fast, several locations managed to break monthly records for heat on Sunday. Many others experienced their warmest (or hottest) day ever recorded so late in the autumn, as catalogued by weather.com. In a number of cases, the readings on Sunday were one to two weeks later than any comparable heat in more than a century of record-keeping.
Locations where Sunday was the warmest day notched so late in the autumn include the following (thanks go to Nick Wiltgen and Linda Lam at weather.com for some of the record-heat data used below):
International Falls, MN: 88°F
Duluth, MN: 84°F
Redwood Falls, MN: 90°F
*Fargo, ND: 97°F
Grand Forks, ND: 90°F
Aberdeen, SD: 93°F
Pierre, SD: 95°F
*Broken Bow, NE: 98°F
*Grand Island, NE: 97°F
Lincoln, NE: 94°F
**Colorado Springs, CO: 87°F
(asterisk = October record broken;
double asterisk = October record tied)
The poster child for this autumn heat wave may be Fargo, ND, where the high on Sunday, October 11, was 97°F. Not only was it Fargo’s hottest day of 2015 thus far, but it was by far the warmest temperature ever observed so late in the year. Nothing so toasty had ever been recorded in Fargo any later than September 22, when the city soared to 101°F in 1936. Even in midsummer, hitting 97°F isn’t all that common in Fargo: from 1990 to 2014, that mark was reached in only 7 of 25 years.
Further south, the readings were less anomalous, but still hot enough to break records and break out summertime garb. Wichita Falls, TX, simmered with a daily record high of 97°F, and San Diego, CA, basked in record daily warmth of 94°F. The warmth in California was also aided by downslope winds, but in this case heading the other direction--blowing offshore from east to west, around the south side of the sprawling zone of high pressure covering the U.S. West. Such patterns often give California its warmest temperatures of the year, along with enhanced wildfire risk. Camarillo, CA, set an all-time high of 108°F on Friday, October 9, breaking the mark of 103°F set on September 24, 1978.
Not to be outdone, parts of south-central Canada got in on the warmth, which added a balmy touch to the Thanksgiving weekend. (Canada’s Thanksgiving is celebrated each year on what’s commonly known in the U.S. as Columbus Day and recognized as Indigenous Peoples' Day at a number of U.S. locations). Saskatoon, Saskatchewan, hit 78°F on Saturday, compared to the daily record of 80°F and an average high of around 54°F. Winnipeg, Manitoba, made it to 75°F on Sunday, falling short of the daily record of 79°F but still more than 20°F above average. High winds were blasting the Northern Plains on Monday behind a sharp cool front ushering in more seasonable air. Wind gusts could reach 120 km/hr (75 mph) in parts of the Winnipeg area, according to Environment Canada. High wind warnings are in effect for eastern ND and SD and western MN; winds gusted to 59 mph at Cooperstown, ND, on Monday morning.
Figure 2. State-by-state ranking of average temperatures observed in September for the contiguous United States. Image credit: NOAA National Centers for Environmental Information.
Second-warmest September in U.S. weather records
With a 48-state average that came in 3.7°F above the 20th-century average, last month was the second-warmest September for the contiguous U.S. in 121 years of record-keeping, topped only by September 1998. A set of nine widely dispersed states had their warmest September on record: Connecticut, Colorado, Maine, Michigan, Minnesota, New Mexico, Rhode Island, Utah, and Wisconsin. The month was also on the dry side, coming in as the 21st-driest September of the past 121 years.
For the year to date, the 48-state average is eighth warmest on record, although that obscures record Jan-Sep warmth in four states (California, Oregon, Washington, and Nevada) and below-average readings from the mid-Mississippi Valley to New England.
Figure 3. Comparison of first-freeze climatology (1981-present) with conditions to date at first-order observations stations across the United States. Colored areas on map show the average date of the first freeze. The circles show whether each location has had a freeze (large purple) or no freeze yet (small gray). Image credit: Brian Brettschneider, @Climatologist49.
Figure 4. A view toward Centennial Ridges Trail in southeast Canada’s Algonquin Park (about 150 miles northeast of Toronto) on October 7, 2015. Sugar maples in the park hit peak on October 3 this year. Since 1975, the peak date has ranged from as early as September 15, 1982, to as late as October 9, 1996. Image credit: Algonquin Provincial Park.
The widespread warmth of September has delayed the first frost across many parts of the northern U.S. and the first snow over much of the Rockies. Most of South Dakota and western Nebraska normally get their first freeze by the end of September but have yet to touch 32°F this year (see Figure 3 above). The legendary fall foliage of New England has also taken a hit, as the color change is at least a week later than average in some locations--enough to compromise leaf-peeping for those who scheduled short trips well in advance. Yankee magazine’s live fall foliage map on Monday showed only a small part of northernmost New York and northern Vermont at peak color, with most of northern New England now in the “moderate” category. Northernmost Maine is also now near peak, according to the state’s official foliage website. By contrast, Yankee’s interactive map of average conditions shows that northern New England is usually at or past peak by this point, with the current conditions more comparable to those found on average during the last week of September.
The foliage-hastening effects of decreasing sunlight should begin to outweigh the warmth-induced delay as October proceeds. Temperatures this month over northern New England are running a bit below average, which should also help get the fall foliage spectacle rolling.
Figure 5. MODIS image of Tropical Storm Nora to the southeast of Hawaii's Big Island as seen from NASA's Aqua satellite on Sunday, October 11, 2015. At the time, Nora was at peak strength with top winds of 70 mph. Image credit: NASA.
Action in the Pacific: Tropical Storm Nora, 96E, 91W, and 92W
Earth's only active tropical cyclone on Monday was Tropical Storm Nora, which is expected to turn north on Tuesday east of Hawaii, missing the islands by over 500 miles. Steadily increasing wind shear should reduce Nora to a remnant low by Thursday.
Our three top models for predicting tropical cyclone genesis predict that an area of disturbed weather located at 8 am EDT Monday about 675 miles south of Manzanillo, Mexico (Invest 96E) will develop into a tropical depression late this week. This system is expected to move westwards at 10 - 15 mph and eventually turn north well east of Hawaii. Satellite loops show that 96E has an impressive amount of spin, but very few heavy thunderstorms. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave 96E 2-day and 5-day odds of development of 10% and 80%, respectively.
Two tropical disturbances in the Western Pacific are forecast by the GFS and European models to develop into tropical depressions later this week: Invest 91W and Invest 92W. 91W was near Guam in the U.S. Mariana Islands on Monday, and is likely to move west to west-northwest this week, reaching a position a few hundred miles east of the Philippines' Luzon Island by the weekend. This storm will likely be the larger and more dangerous of the two systems. 92W will move west-northwest and pass through the northern Mariana Islands on Friday and Saturday.
Nothing cooking in the Atlantic
None of our reliable models for forecasting tropical cyclone development are predicting development of anything in the Atlantic over the next five days. There should be an increase in heavy thunderstorm activity over the Western Caribbean this weekend and early next week that will be worth watching for tropical cyclone development, though.
Bob Henson (temperatures), Jeff Masters (tropical)
Figure 1. High temperatures observed on Sunday, October 11, 2015. Image credit: The Weather Channel.
Even though we’re now into mid-October, when average temperatures are falling fast, several locations managed to break monthly records for heat on Sunday. Many others experienced their warmest (or hottest) day ever recorded so late in the autumn, as catalogued by weather.com. In a number of cases, the readings on Sunday were one to two weeks later than any comparable heat in more than a century of record-keeping.
Locations where Sunday was the warmest day notched so late in the autumn include the following (thanks go to Nick Wiltgen and Linda Lam at weather.com for some of the record-heat data used below):
International Falls, MN: 88°F
Duluth, MN: 84°F
Redwood Falls, MN: 90°F
*Fargo, ND: 97°F
Grand Forks, ND: 90°F
Aberdeen, SD: 93°F
Pierre, SD: 95°F
*Broken Bow, NE: 98°F
*Grand Island, NE: 97°F
Lincoln, NE: 94°F
**Colorado Springs, CO: 87°F
(asterisk = October record broken;
double asterisk = October record tied)
The poster child for this autumn heat wave may be Fargo, ND, where the high on Sunday, October 11, was 97°F. Not only was it Fargo’s hottest day of 2015 thus far, but it was by far the warmest temperature ever observed so late in the year. Nothing so toasty had ever been recorded in Fargo any later than September 22, when the city soared to 101°F in 1936. Even in midsummer, hitting 97°F isn’t all that common in Fargo: from 1990 to 2014, that mark was reached in only 7 of 25 years.
Further south, the readings were less anomalous, but still hot enough to break records and break out summertime garb. Wichita Falls, TX, simmered with a daily record high of 97°F, and San Diego, CA, basked in record daily warmth of 94°F. The warmth in California was also aided by downslope winds, but in this case heading the other direction--blowing offshore from east to west, around the south side of the sprawling zone of high pressure covering the U.S. West. Such patterns often give California its warmest temperatures of the year, along with enhanced wildfire risk. Camarillo, CA, set an all-time high of 108°F on Friday, October 9, breaking the mark of 103°F set on September 24, 1978.
Not to be outdone, parts of south-central Canada got in on the warmth, which added a balmy touch to the Thanksgiving weekend. (Canada’s Thanksgiving is celebrated each year on what’s commonly known in the U.S. as Columbus Day and recognized as Indigenous Peoples' Day at a number of U.S. locations). Saskatoon, Saskatchewan, hit 78°F on Saturday, compared to the daily record of 80°F and an average high of around 54°F. Winnipeg, Manitoba, made it to 75°F on Sunday, falling short of the daily record of 79°F but still more than 20°F above average. High winds were blasting the Northern Plains on Monday behind a sharp cool front ushering in more seasonable air. Wind gusts could reach 120 km/hr (75 mph) in parts of the Winnipeg area, according to Environment Canada. High wind warnings are in effect for eastern ND and SD and western MN; winds gusted to 59 mph at Cooperstown, ND, on Monday morning.
Figure 2. State-by-state ranking of average temperatures observed in September for the contiguous United States. Image credit: NOAA National Centers for Environmental Information.
Second-warmest September in U.S. weather records
With a 48-state average that came in 3.7°F above the 20th-century average, last month was the second-warmest September for the contiguous U.S. in 121 years of record-keeping, topped only by September 1998. A set of nine widely dispersed states had their warmest September on record: Connecticut, Colorado, Maine, Michigan, Minnesota, New Mexico, Rhode Island, Utah, and Wisconsin. The month was also on the dry side, coming in as the 21st-driest September of the past 121 years.
For the year to date, the 48-state average is eighth warmest on record, although that obscures record Jan-Sep warmth in four states (California, Oregon, Washington, and Nevada) and below-average readings from the mid-Mississippi Valley to New England.
Figure 3. Comparison of first-freeze climatology (1981-present) with conditions to date at first-order observations stations across the United States. Colored areas on map show the average date of the first freeze. The circles show whether each location has had a freeze (large purple) or no freeze yet (small gray). Image credit: Brian Brettschneider, @Climatologist49.
Figure 4. A view toward Centennial Ridges Trail in southeast Canada’s Algonquin Park (about 150 miles northeast of Toronto) on October 7, 2015. Sugar maples in the park hit peak on October 3 this year. Since 1975, the peak date has ranged from as early as September 15, 1982, to as late as October 9, 1996. Image credit: Algonquin Provincial Park.
The widespread warmth of September has delayed the first frost across many parts of the northern U.S. and the first snow over much of the Rockies. Most of South Dakota and western Nebraska normally get their first freeze by the end of September but have yet to touch 32°F this year (see Figure 3 above). The legendary fall foliage of New England has also taken a hit, as the color change is at least a week later than average in some locations--enough to compromise leaf-peeping for those who scheduled short trips well in advance. Yankee magazine’s live fall foliage map on Monday showed only a small part of northernmost New York and northern Vermont at peak color, with most of northern New England now in the “moderate” category. Northernmost Maine is also now near peak, according to the state’s official foliage website. By contrast, Yankee’s interactive map of average conditions shows that northern New England is usually at or past peak by this point, with the current conditions more comparable to those found on average during the last week of September.
The foliage-hastening effects of decreasing sunlight should begin to outweigh the warmth-induced delay as October proceeds. Temperatures this month over northern New England are running a bit below average, which should also help get the fall foliage spectacle rolling.
Figure 5. MODIS image of Tropical Storm Nora to the southeast of Hawaii's Big Island as seen from NASA's Aqua satellite on Sunday, October 11, 2015. At the time, Nora was at peak strength with top winds of 70 mph. Image credit: NASA.
Action in the Pacific: Tropical Storm Nora, 96E, 91W, and 92W
Earth's only active tropical cyclone on Monday was Tropical Storm Nora, which is expected to turn north on Tuesday east of Hawaii, missing the islands by over 500 miles. Steadily increasing wind shear should reduce Nora to a remnant low by Thursday.
Our three top models for predicting tropical cyclone genesis predict that an area of disturbed weather located at 8 am EDT Monday about 675 miles south of Manzanillo, Mexico (Invest 96E) will develop into a tropical depression late this week. This system is expected to move westwards at 10 - 15 mph and eventually turn north well east of Hawaii. Satellite loops show that 96E has an impressive amount of spin, but very few heavy thunderstorms. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave 96E 2-day and 5-day odds of development of 10% and 80%, respectively.
Two tropical disturbances in the Western Pacific are forecast by the GFS and European models to develop into tropical depressions later this week: Invest 91W and Invest 92W. 91W was near Guam in the U.S. Mariana Islands on Monday, and is likely to move west to west-northwest this week, reaching a position a few hundred miles east of the Philippines' Luzon Island by the weekend. This storm will likely be the larger and more dangerous of the two systems. 92W will move west-northwest and pass through the northern Mariana Islands on Friday and Saturday.
Nothing cooking in the Atlantic
None of our reliable models for forecasting tropical cyclone development are predicting development of anything in the Atlantic over the next five days. There should be an increase in heavy thunderstorm activity over the Western Caribbean this weekend and early next week that will be worth watching for tropical cyclone development, though.
Bob Henson (temperatures), Jeff Masters (tropical)
🍁 Fall foliage nearing peak, especially central/north Maine. Here are some webcam shots today. #mewx pic.twitter.com/vCiyxUBNkG
— NWS Caribou (@NWSCaribou) October 10, 2015Extreme Weather Heat Hurricane
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.