Tuesday, November 26, 2013

Thanksgiving Week 2013 Weather Forecast

Dry and cold in the Heartland, Major storm along the East Coast to impact travel.

Remaining dry through the end of the upcoming Thanksgiving weekend with a 0% chance of precipitation.  Temperatures colder than normal are expected, but warming to above normal by the weekend.  Normal highs/lows this time of year are low 40's and low 20's. 

East Coast Winter Storm:
A major winter storm is taking shape and will significantly impact travel from the southeastern U.S. up into New England.  Snowfall amounts could exceed 12 inches along the Appalachian mountains into Ontario and Quebec in Canada.  Fortunately, the temperatures will be too warm for snow to reach the coastal population corridor from Boston to New York City and Washington D.C.   Heavy rain, in excess of 2 to 3 inches, will impact the coastal region northeastward from Washington, D.C.  Note the forecast below for New York City showing that the storm will clear that region by Thanksgiving morning.

A look Ahead:
A major cold wave is likely toward the end of next week.  Precipitation is also likely when the cold Arctic air arrives so this is our potential first "plowable" snowfall.  It is still too early to estimate potential snowfall amounts for the area but there is high confidence that the weather pattern will bring us our first real winter weather by the end of next week.  Precipitation is more difficult to forecast ahead of time than temperature.  Airmasses control the temperatures and the airmass will cover the entire region.  However, the band of snowfall is limited in its size and controlled by the availability of moisture arriving int he region.  The exact location of the snowfall in Nebraska and the intensity of snowfall can't be accurately forecast this far ahead of time.  This extended outlook is provided as a "heads up" outlook for a potential snowfall in our area and does not have the confidence that we have in forecasting the onslaught of Arctic air at the end of next week

The following forecast map shows the weather for 06UTC December 7 (or midnight CST December 6).  The areas in green show where precipitation could be occurring.  The furthest south blue line is 0C (32F). The next blue line north is -10C (+14F). The air mass in southern Canada is colder than -30C (-22 F) and sliding southward into the Plains.

The following forecast map shows the weather for 06UTC December 10 (or midnight CST December 9).  The areas in green show where precipitation could be occurring.  The furthest south blue line is 0C (32F). The next blue line north is -10C (+14F). 

Related link:  Lincoln Weather and Climate

Wednesday, November 20, 2013

First Snowfall of the Season

November 20, 2013:  southeast Nebraska will expereince its first blast of winter weather Thursday into the weekend with arrtic air plunging out of Canada and our first snwofall fo the season.

As of 13:45 GMT (8:45 am CST) November 20, 2013 a large area of extremely cold air covers western Canada.  This mass of Arctic temperatures, more typical of January,  has started to move across the border into the northern Plains.  Note on the map that the temperatures in the southern Prairie Provinces of Canada are -20F to -30F.

The following map shows the forecast total snowfall accumulation.  This event will be moisture starved so snowfall amounts will be on the relatively light side.

The official forecast from the Omaha/Valley, NE, NWS office is:
  • Thursday Rain likely, mainly after noon. Cloudy, with a temperature rising to near 37 by noon, then falling to around 32 during the remainder of the day. Breezy, with a north wind 11 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
  • Thursday Night Snow. Low around 20. Blustery, with a north wind 16 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.

Looking out through November 25-29 shows a high probability of colder than normal temperatures in our area and much of the lower 48 states.

The 6-10 day outlook shows a higher chance of drier than normal than wetter than normal so it doesn't look like we will have much snowfall during this anticipated cold spell.

Related links:
 Lincoln's Snowfall Climate Data

Lincoln's November 2013 daily weather and climate data

Tuesday, November 12, 2013

October 2013 Statewide Temperature and Precipitation Rankings

October 2013 Statewide Temperature and Precipitation Rankings
Nebraska had its 24th coldest October on record (see the map below) out of 119 years of data.  Iowa to Colorado and up north into SD, ND, MT, ID and WA all had a "much warmer than Normal" September 2013.  From Oklahoma north to North Dakota and all the way west to the West Coast, temperatures averaged below normal in October 2013.The only states with above normal temperatures in October 2013 were from Virginia through New England and Florida.  The average temperature for the lower 48 states was the 37th coldest October on record.

In contrast, and not shown on the map, Alaska had it warmest October on record this year.

Nebraska experienced much above normal precipitation during September 2013.  It was Nebraska's 112th driest (or 8th wettest) October on record. The scale goes from driest to wettest so the 119th driest is in fact the 1st wettest, the 118th driest is in fact the 2nd wettest, etc.Wyoming had their 117th driest (or 3rd wettest) October on record. North Dakota and South Dakota were also much above normal for their average precipitation.  The ID, OR, WA, CA, AZ and NM had below normal to much below normal precipitation.  The southeastern U.S. and New England were also drier than normal in October 2013.

The U.S. Highlights from the National Climatic Data Center are located below the two maps.

Climate Highlights — October
  • The average temperature for the contiguous United States during October was 53.6°F, 0.6°F below the 20thcentury average, making it the 37th coolest October on record.
  • Below-average temperatures dominated west of the Mississippi River. Oregon had its 11th coolest October, with a monthly temperature of 46.3°F, 3.0°F below average. No state had October temperatures that ranked among the ten coolest.
  • Above-average temperatures were observed across the Mid-Atlantic and Northeast. Delaware tied its tenth warmest October with a monthly temperature 3.5°F above average. Near-average temperatures were reported across much of the Midwest and the Southeast.
  • The Alaska statewide average temperature during October was 8.8°F above the 1971-2000 average marking its warmest October on record in the 95-year period of record. The previous record warm October occurred in 1925, when the temperature was 7.7°F above average. Locally, the Fairbanks average October temperature of 36.1°F was 11.9°F above normal. In addition to the above-average temperatures, many low elevation locations received much-below-average snowfall.
  • The October national precipitation total was 2.23 inches, 0.12 inch above the 20th century average.
  • The near-average October precipitation total for the contiguous U.S. masked both wet and dry extremes. The East and West Coasts were drier than average during October. California and Oregon both had their 11th driest October. Rhode Island and Massachusetts had their fourth driest and ninth driest Octobers on record, respectively.
  • Much of the central U.S. was wetter than average, stretching from the Southern Plains, into the Northern Plains and Midwest. Nebraska, North Dakota, South Dakota, and Wyoming each had a top ten wet October.
  • The Alaska statewide average precipitation during October was 74.5 percent above the 1971-2000 average and marked the third wettest October in the 95-year period of record for the state. The weather pattern that brought the above-average temperatures to the state also brought an abundance of precipitation, mainly in the form of rain, causing minor flooding. Valdez received 17.83 inches of rain during October, 8.69 inches above average, and the wettest October on record for the location.
  • An early-season blizzard hit northeastern Wyoming and western South Dakota on October 3rd–5th, dropping up to three feet of snow with winds in excess of 70 mph. Rapid City, South Dakota received 23.1 inches of snow, breaking several October snowfall records for the city. An estimated 20,000 head of cattle died during the event in South Dakota, approximately 15 to 20 percent of the state's entire cattle population. The storm was rated a Category 3 (Major) on the Regional Snowfall Index.
  • According to analysis by the Rutgers Global Snow Lab, the October snow cover extent across the contiguous U.S. was the fifth largest in the 46-year period of record at 132,000 square miles, more than 60,000 square miles above average. Conversely, the Alaska snow cover extent was 53,000 square miles below average, and the ninth smallest October snow cover extent on record.
  • According to the October 29th U.S. Drought Monitor report, 34.7 percent of the contiguous U.S. was in drought, down 6.5 percent compared to the beginning of the month and down 26.4 percent since the beginning of the year. Drought improved for parts of the Central Rockies and Great Plains, while drought conditions developed across parts of the Northeast.
  • On a local basis during October, there were slightly more (1.2 times as many) record cold daily highs (698) and lows (407) as record warm daily highs (242) and lows (689).
  • Based on NOAA's Residential Energy Demand Temperature Index (REDTI) , the contiguous U.S. temperature-related energy demand during October was eight percent below average and the 58th lowest in the 1895-2013 period of record.

Wednesday, November 6, 2013

November 5, 2013 Winter Storm: heavy rain and snow in Nebraska

An early Winter Storm moved across the Heartland on Tuesday November 5, 2013 bringing heavy rain to eastern Nebraska and snow to central and northeastern Nebraska.

A record day in Lincoln and Omaha:  The November 5, 2013 rainfall in Lincoln, 1.20 inches broke the record for that day of the year, 0.70 inches, which was set in 1948. The Omaha rainfall total of 1.00 inches also broke their previous record of 0.99 inches also set in 1948.

The following map shows the radar estimated 24-hour precipitation total with a large area in southeast Nebraska with over 1 inch of rain.

The next map shows the actual measured precipitation amounts for the same 24-hour period and was produced by our local Omaha/Valley, NE, NWS office.

The following animated radar map shows the precipitation moving across our region on
November 5, 2013.  Note that the green is rain and the blue is snowfall.

The heavy rains in Lincoln were responsible for knocking many of the autumn leaves off the trees .  As the following photos from the afternoon of November 5, 2013 show, the ground was covered with many colorful leaves that were forced straight down and off the tree branches.

Finally, while southeastern Nebraska saw only rain, a swath of snowfall extended from SW Nebraska up through northeastern Nebraska and on up to Minnesota. Local snowfall amounts of 9+ inches were observed near Gordon, NE. The following satellite image clearly shows the swath of snow on the ground as of today, Wednesday, November 6, 2013 (note the blue lines that were added to show the snow on the ground.  Clouds cover SE Nebraska. Thank You  NWS Sioux falls for posting this image.

Tuesday, November 5, 2013

Climatology of First Snowfall in Autumn

Headline:November 5, 2013:
The first snowfall of the season is occurring today across central and northeastern Nebraska.

How does this timing compare with the normal date of the first occurrence of measurable snowfall in the Fall?

The following map produced by the Midwest Regional Climate Center shows the median date of the first measurable snowfall.  The "median" is the mid point date between the earliest and the latest observed first measurable snowfall..

The median date ranges from late November in southeastern Nebraska to mid October in the Nebraska Panhandle.

The next map, also from the Midwest Regional Climate Center,  shows the latest observed first measurable snowfall across our region.  Most of southeastern Nebraska including Omaha and Lincoln have waited as long as late December for their first snowfall.

 The following map produced by NOAA shows the median date of the first measurable snowfall for the conterminous United States.

The following graph shows the date of the first measurable snowfall for Lincoln, NE for the time period 1948-2012.  There is a considerable amount of variability from year to year in the timing of our first measurable snowfall, however an upward trend toward later first snowfalls is clearly evident in the graph (note the red line on the graph)..

Lincoln's snowfall climatology: 113 years of data (1900-2012)
Average date first measurable snowfall:  Day 321 or November 17
Last time Lincoln had a November measurable snowfall, year 2007, 0.4 inches
Novembers with measurable snowfall: 82 years (73% of the Novembers)
Novembers without measurable snowfall: 31 years (27% of the Novembers)
Most November Snowfall: 12.6 inches, 1957.
Least November Snowfall (1900-2012): (0.0 and T) 29 years
0 inches: 9 years since 1900; a trace (T): 22 years since 1900.
A trace of snowfall means it was observed but not enough to be measured.

LINK to ALL of the Snowfall  data for Lincoln, NE

Friday, November 1, 2013

October 2013, Lincoln, NE Climate Summary

Headline:  October 2013 was cooler than normal and wetter than normal for Lincoln, NE.

The highest temperature observed in Lincoln, NE in October 2013 was 86F on October 2 and October 4.  

The October 2013 precipitation total in Lincoln, NE was 2.83 inches or 0.86 inches above normal.  October 2013 was the first month with above normal precipitation since May, 2013. The total January 1 through October 31, 2013 precipitation in Lincoln was 25.27 inches or 1.28 inches below the normal of 26.55 inches. See the table below the graph for the Year 2013 precipitation totals).

The following graph shows the Lincoln, NE, October 2013 daily high and low temperatures compared to normal daily highs and lows.  NOTE:  The October 2013 statistics are located below the graph.

The Red Line shows the normal high temperatures;the Blue Line shows the normal low temperatures.
The top of each vertical bar is the high for the day and the bottom of each vertical bar is the low for the day.

Here are the Lincoln, NE, summary statistics for October 2013.
October 2013 Temperature Statistics:
Average High Temperature 64.8 F (1.5 degrees BELOW Normal)
Average Low Temperature 38.6 F (2.0 degrees BELOW Normal)
Mean Temperature 51.7 F (1.5 degrees BELOW Normal)
Note: Mean temperature = the average of all the highs and lows
Number of days ABOVE Normal = 8
Number of Days BELOW Normal = 21
Number of Days exactly Normal = 2
Highest temperature 86 F on October 2 and October 4 

Lowest temperature 24 F on October 25
October 2013 Precipitation Statistics:
Total precipitation 2.83 inches (0.86 inches ABOVE Normal)
Heaviest precipitation 2.06 inches on October 3
Normal January 1 - October 31 precipitation =  26.55 inches
Total precipitation January 1 - October 31 = 25.27 inches
January 1 - October 31 precipitation deficit =  1.28 inches