Record Late Season Snowfalls Redux
Record Late Season Snowfalls Redux
I posted a blog last year at this time on record late-season snowfalls and thought given the big snowstorm in the higher elevations of Pennsylvania and New York on April 22-24 I would produce an update.
April Snow Event of April 22-24, 2012
According to Aaron Tyburski at the NWS office in State College, Pennsylvania, the recent snowstorm that affected portions of the Appalachians and western New York State was the most substantial late-season snow event since a major late-April snow in 1928. The current storm, however, was not quite as widespread or severe as the 1928 event or as bad as some forecasts had predicted. In the end, temperatures remained just warm enough at lower elevations to cause most precipitation to fall as rain. Only elevations above about 1,500 feet received substantial accumulations. Peak state totals include 16.0” at Arkwright, New York, 14.0” at Sylvania, Pennsylvania, 6.0” at Frostburg, Maryland, and 5.0” at Crawley, West Virginia. An earlier report posted by the NWS of 23.7” at Laurel Summit, Pennsylvania (elevation 2,770’) has now been scaled back to just 13.7”. UPDATE 11p.m EST 4/24: Now, the NWS storm survey has reinstated the 23.7" figure from Laurel Summit. Pittsburgh received no accumulation as previously forecast since the temperature never managed to fall below 35°. Buffalo, New York picked up just an inch or so. It appears the largest town to receive substantial snowfall was Johnstown, PA where 2-8” accumulated depending just where (what elevation) you live in the city of 24,000.
Heavy snow in the Poconos of northeast Pennsylvania was responsible for numerous traffic accidents along Interstate 80. Photo still from WNEP Channel 16 News, Scranton.
Some Historic Late Season Snowstorms in the Eastern U.S.
The April 27-28, 1928 Upper Ohio Valley Snowstorm
The greatest late April snow previous to this week’s event was that of April 27-28, 1928 when up to 40” of snow fell in the mountains of West Virginia. The storm formed in the Gulf of Mexico with a secondary low centered over western North Carolina. The storms converged off the coast of Virginia and slowly moved north (somewhat similar to the current storm). Cold air aloft dropped the snow levels to about 2000’ in the central Appalachian region. Maximum state snowfalls were said to have been 40” in West Virginia (with 19” at Elkins), 36” in Pennsylvania, 15.5” in Kentucky, 14.0” in Virginia, and 13.0” in North Carolina (although specific city totals were sadly lacking in the report). The Monthly Weather Review published this slightly confusing map of the precipitation and snowfalls recorded:
Map from Monthly Weather Review, June 1928.
The May 4th Snowstorm in 1774
A general snowfall of around 4” occurred from northern Virginia to southern New England. Both Philadelphia and New York City reported “a considerable quantity of snow”. Thomas Jefferson and George Washington both noted the event in their diaries.
The Great April Fools Day Snow of 1807
Probably the deepest April snowfall in modern history occurred on April 1, 1807 from Illinois to the Mid-Atlantic. The track of the storm was not the usual coastal nor’easter variety that normally produces great snows but rather the low moved northeast from the lower Tennessee Valley and across the mid-Atlantic states and offshore around New York City. To the north of the storm path incredible snowfalls were reported. The westernmost report we have came from Vincennes on the Illinois-Indian border with an 11” accumulation but it was in Pennsylvania, New York and New England that astonishing snowfall was reported including: 52” at Montrose, Pennsylvania near Scranton; 54” at Utica, New York, 52” at Lunenburg, Vermont; 60” at Danville, Vermont; 48” at Montpelier, Vermont; and 42-48” at Norfolk, Connecticut.
The June 1816 Snows of the ‘Year without Summer’
Most famous of all cold and snowy late season events would have to be the infamous 1816 ‘Year without Summer’ and the snowfall in June that occurred in the eastern U.S. and Canada. On June 6th accumulating snow was observed as far south as the Catskills in New York (where one inch was reported) and highlands of central and northwest Pennsylvania. Snowflakes were seen at sea level as far south as ten miles north of tidewater on the Hudson River just north of New York City. The deepest accumulations were reported in the mountains of Vermont where drifts of 12-18” were measured. Quebec City in Canada reported 12” on level with drifts up to two feet deep.
The even Greater Snow of June 1842
It should be noted that June snowfall in the Northeast is not a unique event to 1816. On June 11, 1842 widespread snow fell over northern New York and New England and snowflakes were observed in Cleveland, Ohio, Boston, Massachusetts, and even Harrisburg, Pennsylvania (a low elevation site). Accumulations of 10-12” were common in Vermont, so this event was actually more extreme than the more famous snow of June 1816.
Pennsylvania July Snowfalls
Ben Gelber mentions in his book The Pennsylvania Weather Book the strange occurrence of snow flurries in the state’s highlands of Bradford County on July 4, 1859. Snow flurries also occurred again here on July 2, 1918.
Average and Actual Dates of Last Measurable Snowfall for Selected Cities
Below is a table I produced in April of 2011 showing what the date of the average last measurable snowfall is for a season, the latest such on record, and what the last date was for the 2009-2010 season. I have done the same for this 2011-2012 season for comparison in the table below this. Of course, there is a possibility that additional measurable snow may yet fall this season in places like Bismarck, Great Falls and some of the other western sites:
Latest Measurable Snowfall for Selected Cities in the USA
Some All-time Single-Greatest Storm Snowfall Records in the U.S.A. that occurred during April and May
The Southern Appalachians have also recorded some phenomenal late season snowfalls including a reported 60.0” accumulation at Newfound Gap, North Carolina on April 2-5, 1987 and, even more incredible, another 60.0” accumulation at Mount Pisgah, North Carolina on May 5-8, 1992!
World-record Snowfalls During April
The fact is that the greatest snowfalls ever experienced in the world have occurred during the month of April and that for portions of the High Plains and Rocky Mountains April and May usually produce the heaviest accumulating snowstorms.
World Record 24-hour Snowfall at Silver Lake, Colorado
The greatest 24-hour snowfall officially measured in the world was the 75.8” that fell at Silver Lake, Colorado (in the mountains just west of Boulder) on April 14-15, 1921. The storm total was an amazing 95.0” over a 32½ hour period.
Storm precipitation (melted—in inches) total for Silver Lake event from April 1-15, 1921 Map from ‘Monthly Weather Review’, Feb. 1953, p. 39.
World-record Single Greatest Snowfall in the Sierra Nevada
The greatest single-storm snowfall on record in the world was 194” (over 16 feet!) that fell during a massive spring blizzard at the Sierra Nevada railway summit station of Norden over the four-day period of April 20-23, 1880.
An historic photo of the Norden station during the winter of 1887.
World-record 19-hour Snowfall and European Record
Europe’s greatest 24-hour snowfall happened at Bessans in the French Alps on April 5-6, 1959 when 67.8” accumulated in just 19 hours (a world record for a 19 hour period).
Bessans, France is a popular ski resort in the French Alps.
REFERENCE: Early American Winters: Vol 1: 1604-1820 and Vol 2: 1821-1870 by David M. Ludlum, American Meteorological Society, 1966, 1968. The Pennsylvania Weather Book by Ben Gelber.
Christopher C. Burt
Updated: 5:35 AM GMT on April 25, 2012
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March 2012 Global Weather Extremes Summary
March 2012 Global Weather Extremes Summary
March was notable weather-wise for the extraordinary early spring heat wave that affected the eastern two thirds of the U.S. and southern and eastern portions of Canada. It was one of the most anomalous temperature events on record for anywhere in the world. March heat records were also set in Scotland, Iceland, Norway, the Summit station on the peak of Greenland's ice cap, and Perth, Australia. A massive tornado outbreak in the U.S. killed 39. Cyclone Irina resulted in 72 deaths in Madagascar and severe storms with flooding rains occurred in Hawaii and eastern Australia.
Below is a summary some of the month’s highlights.
The amazing ‘summer in March’ across the eastern two thirds of the country resulted in a nationwide average temperature of 51.1°F, some +8.6°F above the normal March average of 42.5°F, and thus the 2nd most anomalously warm month in U.S. history (only January 2006 was even more above the average). A large section of the upper Midwest experienced temperatures more than 15°F above normal.
This map shows how widespread the March heat event was with about half of all the continental state divisions reporting their warmest March on record. Map from NCDC.
Jeff Masters has already commented in detail about the event as I also did in a blog on March 23.. So please refer back to our earlier blogs on the subject for more details.
As the eastern two-thirds of the country sweltered it was, in contrast, unusually cold in the western states of Washington, Oregon, and California. Some very unusual late-season snowfalls occurred in Oregon where heavy snow fell right on the Pacific coastline of Oregon. 8.5” of snow accumulated at Tillamook, 7.5” at Newport, and 3.5” at Bandon on March 12. Inland, a late-season record heavy snowfall of 7.5” accumulated in Eugene on March 20-21. A record dry rainy season in California was rudely interrupted by torrential rains in mid-March. One location (Scotts Creek) in the Santa Cruz Mountains south of San Francisco picked up 20.32” of rain on March 10-13.
A freak late-season snowfall blankets the coastal Oregon town of Lincoln City on March 12. Photo from wunderground.com and taken by Kristina Rinell.
While Oregon and Washington reported close to their wettest March on record in Colorado it was the driest such and most ski resorts reported their lowest March snowfalls on record. Texas received much greater rainfall than average helping to alleviate the drought conditions of last year.
A massive tornado outbreak on March 2-3 killed 39 people from Indiana to Alabama. Approximately 80 separate tornados formed including a rare early-season EF-4 twister that hit Henryville, Indiana killing 12 in that small town alone. An excellent summary of the event can be found here.
An aerial view of the damage inflicted on Henryville, Indiana by the EF-4 tornado that killed 12 in the town on March 2. Photographer unknown.
Hawaii was affected by a series of strong weather systems March 4-8 that produced severe thunderstorms, one of which produced a state-record size hailstone 4” in diameter on the north coast of Oahu. An amazing 45.95” of rain fell at Hanalei during the storm period including 35.97” in just the two-days of March 7-8.
The coldest temperature in the northern hemisphere during March was -72.9°F (-58.3°C) at Summit station in Greenland on March 12. In spite of this cold reading, a March monthly record high temperature of 11.3°F (-11.5°C) was set at the Summit station on March 24. A remarkable rise of almost 85° in two weeks.
SOUTH AMERICA and CENTRAL AMERICA
I am unaware of any major extreme weather events in Central or South America this past March.
Much of Western Europe experienced a very dry and abnormally warm March. Portions of Italy received no measureable precipitation whatsoever and for most of all of southern Europe it was the driest March on record. In the U.K. it was the driest March since 1953 and 5th driest on record exasperating the ongoing drought situation. Temperatures in the U.K. averaged 4.5°F (2.5°C) above normal, the warmest March since 1957 and 3rd warmest on record. The average maximum temperature was, at 6.5°F (3.6°C) above normal, the warmest ever recorded for the month. An all-time record maximum temperature for Scotland was set at Aboyne, Aberdeenshire on March 27th when it reached 74.5°F (23.6°C). The previous record was 72.0°F (22.2°C) at Gordon Castle in March 1957. The coldest temperature reported in the U.K. during the month was 16.7°F (-8.5°C) at Braemar, Scotland on March 18. The greatest 24-hour rainfall was 1.80” (45.6mm) at Cluanie Inn, Highland on March 18-19, and highest wind gust 71 mph at Blackford Hill, Edinburgh, Scotland on March 7.
Iceland also set its warmest March temperature on record when it reached 68.9°F (20.5°C) at Kvisker on March 29th. This smashed the old March record of 65.8°F/18.8°C (set at Eskifjorour on March 28, 2000) by an astonishing 3°F (1.7°C).
Apparently a new March heat record for Norway was also set by an even wider margin. A temperature of 73.6°F (23.1°C) was recorded at Landvik Grimstad on March 27 beating the old national March heat record of 67.6°F (19.8°C) set at Frederiksberg on March 25, 1945.
A long-term drought in portions of central Africa has resulted in a series of large wildfires in the region surrounding Mt. Kenya, displacing much of the wildlife the area is so famous for.
The hottest temperature in the world (and, of course, northern hemisphere) during March was 114.8°F (46.0°C) measured at Abu Na Ama, Sudan on March 14.
Tropical Cyclone Irina churned about the Mozambique Channel (between Mozambique and Madagascar) for 7 long days March 2-8. It never made landfall and its winds topped out at just 85 mph, but persistent flooding rains affected mountainous areas of southern Madagascar causing flash floods that killed at least 72. A further 8 deaths were attributed to the storm in Mozambique.
Heavy snows in the mountains of Afghanistan resulted in an avalanche that killed at least 37 in the northeastern village of Shirinazen, Badakshan Province on March 3-4.
An unusual (for time of year and southerly latitude) tropical storm, named Pakhar, came ashore in southern Vietnam near Ho Chi Minh city (Saigon) on March 31. Fortunately the storms 115 mph winds had diminished to just 50 mph as it crossed the Mekong Delta region so only 4 deaths were reported.
March was the 4th wettest nationwide in 113 years of record. It also was abnormally cool, with maximum average temperatures ranking as the 4th coolest on record. A marked exception to the general coolness was the southwestern corner of Western Australia, especially in and around Perth. Perth recorded its warmest March temperature on record when it reached 106.5°F (41.4°C) on March 11, part of a record tying March heat wave that lasted four days with 100°F (38°C)+ temperatures (March 9-12). The highest temperature in the country and the southern hemisphere for the month was 112.3°F (44.6°C) at Kalbarri on March 9. The coldest temperature in the country for the month was 32.0°F (0.0°C) at Mount Read, Tasmania on March 23.
A very cool month for all of Australia except for the coastal region of Western Australia. Map courtesy of Australian Bureau of Meteorology.
Record rainfall during the first week of the month resulted in widespread flooding in portions of northern Victoria, southern and western New South Wales, and central Australia. Several sites recorded their all-time calendar day rainfall records during this week. The greatest single-day rainfall measured was 13.47” (342.2mm) at Daradgee, Queensland on March 26.
One of the wettest March’s on record, and, in fact, THE wettest March on record for widespread portions of New South Wales. Map courtesy of the Australian Bureau of Meteorology.
One of the creepier aspects of the flooding was a spider invasion around Wagga Wagga in New South Wales when floodwaters forced arachnids (in this case wolf spiders) from their burrows into surrounding brush where they wove phantom-like webs.
A couple of photos of the blanket of cobwebs produced by wolf spiders escaping floodwaters near Waga Waga in New South Wales. Photos from Reuters.
NEW ZEALAND/SOUTH PACIFIC
Some of the worst flooding in Fijian history killed at least 5 and displaced 8,000 on Viti Levu following a week of torrential rainfall that culminated in Cyclone Daphne passing over the island chain on March 31.
French Polynesia (where Tahiti is located) experienced abnormally warm temperatures and an all-time absolute maximum temperature of 95.7°F (35.4°C) was registered at the town of Hereheretue on Tuamotu Island on March 9th.
New Zealand’s extremes for the month were a maximum temperature of 84.6°F (29.2°C) at Timaru, South Island on March 24, a minimum temperature of 27.3°F (-2.6°C) at Lake Pukaki (March 26) and also Hanmer Forest on March 9, South Island. The greatest daily rainfall was 6.61” (168mm) at North Egmont on March 2 and also at Kerikeri on March 18, both on North Island. A wind gust of 99mph (158 km/h) was measured at Brothers Island on March 3.
The coldest temperature in the southern hemisphere and the world during March was -97.8°F (-72.1°C) recorded at Dome A site on March 28th.
KUDOS Thanks to Maximiliano Herrera for global temperature extremes data, Stephen Burt for the U.K. extremes, and Jeremy Budd for New Zealand weather extremes. Also special thanks to Trausti Jonsson of the Icelandic Meteorology Office for information concerning the new March heat records in Iceland and Norway.
Christopher C. Burt
Updated: 7:31 AM GMT on April 16, 2012
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State-by-State and Regional Analysis of Temperature and Precipitation Trends
State-by-State and Regional Analysis of Temperature and Precipitation Trends 1895-2011
I’ve been pouring over the statistical database that the NCDC maintains on temperature and precipitation trends and pulled together a brief state-by-state analysis. The database begins in 1895 (when the U.S. Weather Bureau began to homogenize its observation techniques) and is current up to February 2012. There are some surprises, but by and large the trend is certainly towards warmer and wetter conditions in most regions of the country.
Here is what the trends have been for each state (excluding Alaska and Hawaii). The complete analysis can be found here.
I’ve noted the overall trend for each state after the statistics and highlighted in bold the cases where the trend change has been significant; meaning a change in temperature greater than 1.0°F (up or down) or a change in precipitation greater than 5% (dryer or wetter) over the long-term mean. The percentage is change in precipitation over the past 116 years relative to the state’s long-term average:
The Case of Texas
Although last year was the 2nd warmest and 2nd driest year on record for the state of Texas, the long-term trend shows little change in either temperature or precipitation over the past 116 years for America’s largest state (ex-Alaska), one of the few states to experience such (others include North Carolina, Oregon, Florida, and Georgia).
There has been a spike of warmer than normal temperatures in Texas since 2000 but over the long-term this has been mitigated by a long period of cooler than normal temperatures between 1958-1997.
Extreme variability seems to by the ‘normal’ for Texas precipitation on a year-on-year basis, so in spite of last year’s record drought, the overall trend shows little change.
Only six states have experienced a cooling trend (but none ‘significant’—cooler by 1°F or more). The states showing the greatest cooling trend are Alabama (-0.7°F), Georgia (-0.6°F), and Mississippi (-0.6°F). Forty states have experienced a warming trend (with 20 showing a significant 1°F or more increase in temperature. The states showing the greatest increase in temperature are North Dakota (+2.6°F), Nevada (+2.4°F), and Rhode Island (+2.4°F). Three states have shown no change: Texas, Maine, and West Virginia.
My crude attempt at mapping the temperature trends (I’m not a cartographer or Photoshop wiz, sorry!). The deep red indicates states that have seen a +1.0°F or more increase in temperature above the 116-year mean. The orange states have seen a minor warming (+0.1°-0.9°F) and the blue states have seen a decrease in temperature over the long-term mean. Maine, Texas and West Virginia showed no change in their temperature trends.
Forty-one (41) states have trended wetter with 34 of these ‘significantly’ wetter (a change of more than 5% over the long-term mean). The greatest increase has been in Massachusetts where an amazing increase of 29.2% has occurred over the past 116 years. The other states showing the greatest increase in precipitation are Rhode Island (+28.3%), South Dakota (+25.7%), and Connecticut (+24.6%). Only 7 states have seen a drying trend and only 2 of those ‘significantly’ so (by more than 5%). The states showing the greatest drying trend are Wyoming (-8.5%), California (-7.7%), and Maine (-4.8%). The Maine figure is especially interesting since every other New England state has seen a significant increase in precipitation. Indeed, the Northeast region as a whole has seen a +12.4% increase in precipitation from the long-term average. The South Dakota trend seems strangely anomalous relative to its surrounding states. South Dakota has relatively few weather stations (COOP or otherwise) that may be a clue to the anomaly. Strange nonetheless (see more about this towards end of blog).
Another crude map illustrating the precipitation trends. The blue states represent where a ‘significant’ increase of 5% or more has occurred. The orange states have seen a decrease, but only California and Wyoming have seen a ‘significant’ decrease of 5% or more. The ‘white’ states have seen either no change or an insignificant change of less than +5% in their respective precipitation trend. Again, these are figures representing percentage change above or below the 116-year average.
Trends by Region
Here is the NCDC official map outlining their regional designations:
All the climatological regions have seen their temperatures increase except for the Southeast that has seen a slight cooling trend (-0.1°F). The Northern Rockies and Plains have seen the greatest temperature increase (+1.5°F), closely followed by the West and Southwest (both +1.4°F). All regions except the West have seen a trend towards wetter conditions with the Northeast leading the way (+12.4%), followed by the Upper Midwest (+10.7%). The West has trended drier by -4.2%.
Here is how the data breaks down by regions:
You can look at more detailed data for your specific location within a state by looking at this map:
Here is a map of all the U.S. Climatological Divisions.
You can see the data or each division by following the link here. This link, for instance, shows the trend for eastern Massachusetts (division 3 in the state). You can look at each and every year’s average annual precipitation for the division on the bar graph under the chart. Below is the precipitation trend for climate division 6 in South Dakota (central part of the state) where the increase has been 35.7%. This is the most anomalous of any division in the U.S. I have yet identified.
For the entire contiguous U.S. the temperature trend has been +1.2°F and +6.1% wetter compared to the mean over the 116 years since 1895.
Christopher C. Burt
Updated: 4:50 AM GMT on April 08, 2012
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March Rains/Snow Make Dent in California’s Dry Winter
March Rains/Snow Make Dent in California’s Dry Winter + Interesting New Real-time Wind Map
As of March 12th California was on track towards one of its driest water seasons on record. San Jose, for instance, had only measured 3.13” since the beginning of the water season on July 1, 2011 (25% of normal to date). Most of the state was averaging 25-50% of normal rainfall and Sierra snow pack levels were also below normal at similar rates. Since March 13th a series of wet storms have saved the state from the prospect of drought and more storms are forecast over the coming week.
The biggest rainmaker was the storm of March 13-16 (actually two storms back-to-back) that deposited over 20” of rainfall at Scott Creek in the Santa Cruz Mountains south of San Francisco. Ben Lomond picked up 17”. What was remarkable about this event was the extraordinary rain shadow effect that came into play. During the 24-hour period from the morning (5 a.m.) of March 13 to the morning of March 14 (5 a.m.), 14.22” of rain fell at Scott Creek whereas at San Jose Airport, just 25 miles away as the crow flies, a total of just .07” accumulated (and at the home of WU Senior Meteorologist Shaun Tanner near San Jose, NO measureable rain fell)! Over the course of the four-day storm San Jose finally managed to capture .68” of precipitation whereas Scott Creek had a 20.32” total. This was the most extraordinary example of a rain shadow I have ever heard of in the U.S. outside of Hawaii.
This isohyetal map of the San Francisco Bay Area illustrates the amazing rain shadow that the Santa Cruz Mountains cast over the San Jose metro area. San Jose Airport averages 14.90” per season (July 1-June 30) whereas Scott Creek averages 60.50”. The two sites are 22.5 miles apart. I’ve placed an ‘X’ over each site on the map and what their respective 4-day precipitation amounts were March 13-16. Map base shows average seasonal rainfall by 2” increments. From U.S. Army Corps of Engineers, San Francisco.
Here is a brief list of how the past two weeks changed the seasonal rainfall accumulations for some key California cities:
The percentages are what season to-date normals were on 3/13 versus 3/31. The biggest improvement has been over central and northern California. Note that Oakland received more rain in the past two weeks than it had accumulated for the entire season (July 1-March 13) prior to the onset of the recent rains.
The season, however, is still on track to be the driest rain year since 1990-1991 for at least the central portion of the state (assuming that normal rainfall occurs this coming May-June).
The Great April 1880 California Storm
Of course, there is the hope that the late March rainy trend will continue into April. In fact, one the wettest storms in central California history occurred on April 20-21, 1880. This was an extraordinary storm: Sacramento experienced its greatest 24-hour rainfall on record when 7.24” fell on April 20-21 and its two-day total was an astonishing 8.37” both still-standing records. Sacramento’s 14.02” total for the month is the 2nd greatest monthly total for any month of the year since their records began in 1850. San Francisco was on the southern edge of the heaviest precipitation band but still picked up and impressive 3.20” on April 20-21 and 6.43” for the week of April 14-21. Its monthly total of 10.06” remains the wettest April on record since measurements began in 1850. In Napa Valley, north of San Francisco, an amazing 14.70” fell in 24 hours at Mt. Helena and 14.70” was also measured at Helen Mine further north. These figures still stand as the greatest April 24-hour rainfalls in California history. In the Sierra Nevada snow accumulations were off the charts. In fact a world-record single storm snowfall amount of 194” (over 16 feet!) fell at the railway depot Norden on April 20-23 at an elevation of about 7500’. The snow was so heavy it collapsed snow sheds over the railway near Summit (Donner Pass area). Summit depot itself recorded 298” (almost 25 feet) of snow during the month of April, Emigrant Gap totaled 201”, and Truckee 124”. For the winter season of 1879-1880 Summit accumulated an astonishing 783” (over 65 feet) of snow.
Interesting Real-time Animated Wind Map for CONUS
On a completely different topic, Jan Null of Golden Gate Weather Services forwarded me this great map of real-time surface wind flows and speeds for the lower 48 states. I checked its accuracy against actual surface data and it seems to be pretty close to the mark. If you hold your cursor over a point on the map the actual measured winds speeds will pop-up for that location. It will be fun to look at this the next time a big extra-tropical or strong tropical storm makes a pass over the U.S.
Christopher C. Burt
Updated: 4:26 AM GMT on April 04, 2012
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