The Northeast Weather Blog...

Summer 2012...

Posted by: Zachary Labe, 22:08 GMT 3. Květen 2012

Summer 2012 is about to begin according to the meteorological calendar with only less than one month to go. We are also entering that point in the spring season where temperature and precipitation patterns are beginning and generally will lag through most of the summer. It is important to note several simple, but important characteristics during the summer months to help procede with a forecast. Over this period in the year, the polar jet surges to the north locking the cold air across the immediate poles. This allows for a less-amplified and generally meager subtropical jet to linger across the southern United States occasionally throughout the summer, but generally its influences are not noticeable.

(Source: North Carolina State University Meteorology Department)

This orientation prevents most all middle-latitude cyclone development. Therefore the primary precipitation initiators are along associated weak shortwaves and cold fronts. Also warm-core tropical systems play a large role in precipitation trends across the nation later in the summer. This jet stream setup prevents most organized precipitation events occuring over a wide region and therefore regions must rely on convective QPF patterns to receive rainfall. Conditions during the summer are generally drier than the other months of the year. Also given several factors representing seasons, warmer air is funneled across much of the nation with tempereatures upwards of 100F during heatwaves across the Northeast.

Summer patterns are generally more benign than the winter months and therefore less anomalous for the most part.

If one looks at recent decadel trends, average summer means are generally on the positive side regionwide. The last below normal summer for the contiguous United States was 2009 featuring the 34th coolest mean on record. 2011 featured the second hottest summer on record for the United States, especially courtesy of the anomalous heat wave across the southwestern United States.

(Source: NOAA NCDC)

Teleconnections and ENSO regimes have less of an impact on mean conditions across the United States in summer than during the winter months. Therefore direct correlations are a tad more difficult to make especially given an ENSO regime change that will occur this year. The current La Nina (or past La Nina given conditions are no longer being met) will begin to shift towards an El Nino. The image below is the current CFS output for Nino region 3.4 indicating El Nino conditions peaking towards late summer and early fall.

(Source: NOAA CDC CFS)

A study produced by Zhuo Wang, C-P. Chang, and Bin Wang by the Naval Post Graduate School and University of Hawaii reported small correlations for ENSO regimes during northern summers. Link. The findings were generally consistent and noted weak correlations particularly during El Nino summers, while La Ninas featured a dominate and anomalous anticyclone over the central United States. Summers generally were hot nationwide during a La Nina and quite dry across the central United States.

Looking more specifically at teleconnections including the NAO, MJO, etc is not as helpful in the summer. While there is some research to indicate correlations towards temperature and precipitation trends, these studies still do not have clear results.

Another correlation many forecasts like to highlight are temperature trends from the winter and extropolated to summer. Again this correlation is backed by undefined research and statistics. But it is important to note that by late spring, patterns have often set up and become very stagnant for the following few months. Given the recent anomalous warmth (excluding the April cold spell/snowstorm) and dry conditions, it is likely that we may see a continuation of this pattern as we move foward into summer.

(Source: US Drought Monitor)

Drought conditions are already developing across portions of the Northeast despite short term relief from a few synoptic precipitation events over the past week or two. Long term departures are well below normal particularily across much of New England.

This summer forecast will generally be loosely based on the current ENSO status and recent temperature/precipitation trends across the Northeast. While a simplistic forecast in itself, summer forecasts are typically of lower confidence than other times in the year.

While La Nina continues to diminish as we enter neutral conditions presently, SST anomalies are beginning to warm into El Nino ranges according to the latest SOI numbers. Temperature means this summer have a higher likelihood of averaging above normal especially following rollover techniques from the previous 90 days. But without defined ENSO forcing and meager teleconnection influence, I would expect the heat to be more benign than the record warmth during 2010 and 2011. Extended heat waves will be less common than last summer, but a few days of touching 100F cannot be ruled out for the Northeast metropolitan corridor. The hottest conditions are also more likely to persist earlier in the season before the El Nino really begins to intensify.

Current CFS operational output supports a near normal temperature regime for the summer months, but again looking at the latest trends, above normal temperatures are of a higher possibility.

(Source: Climate Prediction Center NOAA)

Precipitation will likely be the bigger news story if the set pattern continues over the next few months. With deficits already greater than 5in+ for the year for some climatological reporting stations, these numbers will likely continue to grow. Drought conditions will worsen, although extreme drought conditions are unlikely. There are no indices and trends signaling any extreme dry weather. Convective precipitation will play a big role and cause localized areas of normal precipitation in some areas.

For hurricane frequency along the east coast, there is nearly a 50/50 probability for a strike. I know this sounds silly, but that is how probability and statistics is used in the meteorological field. There are no definite trends leaning for or against a higher probabilty of an east coast landfall. Current ENSO by early Fall signals that this hurricane season will be quieter than normal.

In general this summer has a higher likelihood to feature slightly above to above normal temperatures with a chance for below normal precipitation for most of the Northeast.

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"Linglestown, PA 2012 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 0
Severe Thunderstorm Warnings- 0
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 9

(Precipitation Stats...)
Flood Watches- 0
Flood Warnings- 0
Flash Flood Warnings- 0

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree days- 0
Highest Temperature- 89F

Categories: Summer Forecast

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51. bwi 19:14 GMT 10. Květen 2012
About a half inch at DCA, and a quarter at BWI. Not, much, but we'll take it. Everything's green for now. Member Since: 04-09-07 Posts: 0 Comments: 1134

52. MariettaMoon 00:38 GMT 11. Květen 2012
Never did a final tally… 2011-2012 Northeast Percent of Normal Snowfall (1981-2010) Caribou ME: 95% Bangor ME: 74% Burlington VT: 46% Portland ME: 71% Concord NH: 80% Rochester NY: 60% Syracuse NY: 41% Buffalo NY: 39% Albany NY: 39% Boston MA: 21% Worcester MA: 62% Binghamton NY: 52% Erie PA: 47% Hartford CT: 66% Providence RI: 53% Wilkes-Barre PA: 40% Williamsport PA: 34% Bridgeport CT: 48% Islip NY: 19% New York NY: 29% N. Queens NY: 19% Newark NJ: 31% Allentown PA: 36% S. Queens NY: 16% Pittsburgh PA: 88% Trenton NJ: 37% Harrisburg PA: 41% Philadelphia PA: 18% Wilmington DE: 26% Atlantic City NJ: 26% Baltimore MD: 9% Dulles VA: 17% Elkins WV: 37% Washington DC: 14% Huntington WV: 23% Charleston WV: 32% Wallops Island VA: 6% Beckley WV: 58% Richmond VA: 44% Lynchburg VA: 52% Roanoke VA: 33% Bluefield WV: 75% Blacksburg VA: 39% Norfolk VA: 9% Danville VA: 64% Member Since: 11-06-11 Posts: 36 Comments: 676

53. TheRasberryPatch 00:43 GMT 11. Květen 2012
around 6pm we got a shower that just before it passed the sun came out and we had a brilliant double rainbow. as for the snowfall for this year. I think I had a few winters where we had less snow. Winter 96-97 comes to mind. I had just bought my snowblower the summer of 96 and I used it once that winter. Didn't we have a winter that was similar around 2007 or 2008 Member Since: 26-01-07 Posts: 72 Comments: 5640

54. HeavySnow 02:35 GMT 11. Květen 2012
I was one of the worst sufferers I see in the year without a winter. Felt like it too. Member Since: 07-07-04 Posts: 18 Comments: 2918

55. originalLT 04:22 GMT 11. Květen 2012
TRP, double rainbows are cool! Especially nice brilliant ones. Only have seen a very few in my lifetime. Member Since: 31-01-09 Posts: 0 Comments: 5056

56. TheRasberryPatch 11:24 GMT 11. Květen 2012
Quoting originalLT: TRP, double rainbows are cool! Especially nice brilliant ones. Only have seen a very few in my lifetime. This was one of the most brilliant rainbows I have ever seen. It appeared to be in my neighbors yard about 250 feet away and it was small. It looked like it only was 500 feet wide. The kids wanted to go find the pot of gold. I was thinking more about somewhere over the rainbow. Member Since: 26-01-07 Posts: 72 Comments: 5640

57. MariettaMoon 16:44 GMT 11. Květen 2012
Quoting TheRasberryPatch: around 6pm we got a shower that just before it passed the sun came out and we had a brilliant double rainbow. as for the snowfall for this year. I think I had a few winters where we had less snow. Winter 96-97 comes to mind. I had just bought my snowblower the summer of 96 and I used it once that winter. Didn't we have a winter that was similar around 2007 or 2008 Yeah, it depends on where you live. I believe a few stations set lowest seasonal snow on record, and a few set lowest Dec-Jan-Feb snow, but I can't say this with 100% confidence as I haven't looked it up. I don't know where the Northeast region as a whole ranks either, I'd imagine somewhere in the bottom-5? I downloaded great statistics program on my computer that I got from my statistics class this spring. I absolutely loved that class (I hated Calculus). These are the seasonal snowfall descriptive statistics for Philadelphia only (1884-1885 to 2011-2012), and doesn't necessarily represent the LSV or other areas of the northeast. For a few that may not know the definition of standard deviation: 1 standard deviation: The average deviation (difference) from the mean. 2 standard deviations: 2 times the average deviation (difference) from the mean SEASONS: 128 MEAN: 22.36" 1 STANDARD DEVIATION: +/- 12.95" 1 STAN DEV RANGE: (9.4" to 35.3") MAXIMUM: 78.7" (2009-2010) QUARTILE 3: 28.9" MEDIAN: 20.6" QUARTILE 1: 14.7" MINIMUM: T" (1972-1973) 2011-2012 TOTAL: 4.0" ST DEV: -1.42 2010-2011 TOTAL: 44.0" ST DEV: +1.67 2009-2010 TOTAL: 78.7" ST DEV: +4.35 Historical Outliers in the data... For a few that may not know the definition of outlier: An outlying observation, or outlier, is one that appears to deviate markedly from other members of the sample in which it occurs. A convenient definition of an outlier is a point which falls more than 2.5 standard deviations above or below the mean. 2009-2010 TOTAL: 78.7" ST DEV: +4.35 1995-1996 TOTAL: 65.5" ST DEV: +3.33 1898-1899 TOTAL: 55.4" ST DEV: +2.55 1977-1978 TOTAL: 54.9" ST DEV: +2.51 The outlier statistics above assume normal distribution (equal distribution of data values) of data (the data actually is not normally distributed, and is skewed right), and therefore uses 2.5 standard deviations from mean as the definition of an outlier. Under normal conditions, 99% of the data values would be expected to fall within 2.5 standard deviations from the mean, and anything over 2.5 standard deviations would be considered as nearly impossible. Since seasonal snowfall at Phila data values do not belong to a normal distribution, we have to be more careful in selecting the thresholds for outliers. According to Chebyshev's theorem, we have to use an interval of +/- 4.0 standard deviations to ensure that at least 94% of the data fall inside this interval. Using Chebyshev's theorem, 2009-2010 would be the only season considered an outlier (+4.35 stan dev). Because the mean snowfall at Philadelphia is 22.36", and 1 stan dev from mean is 12.95", a negative outlier would mean a negative seasonal snowfall total. Since you cannot have negative snowfall in a season, a negative outlier is impossible at Philadelphia. I'm currently constructing a massive historical data analysis for Philly International that the NWS might use on their website. I won't be done till at least the end of this year. These are just fun to look at, and I'm bored now so give me a break lol. Cheers! Member Since: 11-06-11 Posts: 36 Comments: 676

58. MariettaMoon 17:06 GMT 11. Květen 2012
I forgot to note that the 2011-2012 season at Philadelphia is tied for fourth lowest seasonal snowfall on record (1884-1885 to 2011-2012) Here are the 10 highest seasonal snowfalls on record #1. 78.7" (2009-2010) #2. 65.5" (1995-1996) #3. 55.4" (1898-1899) #4. 54.9" (1977-1978) #5. 49.1" (1960-1961) #6. 46.3" (2002-2003) #7. 44.3" (1966-1967) #8. 44.0" (2010-2011) #9. 43.9" (1917-1918) #10. 43.8" (1904-1905) Here are the 10 lowest seasonal snowfalls on record #1. T" (1972-1973) #2. 0.8" (1997-1998) #3. 2.0" (1949-1950) #4. 4.0" (2011-2012) #4. 4.0" (2001-2002) #6. 4.1" (1930-1931) #7. 4.5" (1918-1919) #8. 4.6" (1950-1951) #9. 4.7" (1991-1992) #10. 5.1" (1958-1959) Here are the 10 most days with measureable snowfall #1. 29 (1966-1967) #2. 28 (1904-1905) #3. 27 (1892-1893) #4. 24 (1981-1982) #4. 24 (1917-1918) #6. 23 (1919-1920) #6. 23 (1915-1916) #6. 23 (1886-1887) #9. 22 (1995-1996) #9. 22 (1906-1907) #9. 22 (1903-1904) #9. 22 (1884-1885) Here are the 10 least days with measureable snowfall #1. 0 (1972-1973) #2. 2 (2001-2002) #3. 4 (1997-1998) #3. 4 (1994-1995) #5. 5 (2011-2012) #5. 5 (2007-2008) #5. 5 (1918-1919) #8. 6 (1951-1952) #8. 6 (1949-1950) #8. 6 (1941-1942) #8. 6 (1930-1931) #8. 6 (1912-1913) Member Since: 11-06-11 Posts: 36 Comments: 676

59. TheF1Man 13:41 GMT 12. Květen 2012
Hello everyone how are we doing? I'm very glad to say that I'm home now for the summer! Blizz you were coming back today or something right? Member Since: 23-02-10 Posts: 0 Comments: 571

60. bwi 14:43 GMT 12. Květen 2012
Day 3 QPF looking good. Hopefully it won't all fall at once. Perfect weekend weather in DC. Member Since: 04-09-07 Posts: 0 Comments: 1134

61. Zachary Labe 00:01 GMT 13. Květen 2012
Quoting TheF1Man: Hello everyone how are we doing? I'm very glad to say that I'm home now for the summer! Blizz you were coming back today or something right? Not till Tuesday. For the time being, I have been working on my python/fortran computer programming final project; been working 22 hours and 15 minutes so far, haha, with probably another 6 or so hours left. What a joke. Member Since: 14-12-07 Posts: 253 Comments: 14306

62. TheRasberryPatch 14:06 GMT 13. Květen 2012
Quoting Blizzard92: Not till Tuesday. For the time being, I have been working on my python/fortran computer programming final project; been working 22 hours and 15 minutes so far, haha, with probably another 6 or so hours left. What a joke. you'll find that some things in college are a joke. just go along with it. you never know maybe something similar will occur in real life. use it as a life experience. looks like more rain in the forecast. at least it is occuring during the week, but I'd prefer 7 days without rain to get my yard and stuff ready for summer. Member Since: 26-01-07 Posts: 72 Comments: 5640

63. emilysoccer 09:40 GMT 23. Červenec 2012
nice sharing, so professional. are you like sporting. here you can get the cheap soccer jerseys in China. Member Since: 23-07-12 Posts: 0 Comments: 1

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Cornell University- Atmospheric Sciences Student; Central PA SKYWARN Storm Spotter; American Meteorological Society Member; PA CoCoRaHS Branch Member

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Linglestown, PA
Elevation:	520 ft
Teplota:	89.4 °F
Rosný bod:	71.1 °F
Vlhkost:	55%
Vítr:	2.0 mil/h from the západní
Nárazy větru:	6.0 mil/h
Updated: 16:55 EDT 22. Květen 2013 Station History