Northeast Weather Blog

Last Updated: 11:40 PM GMT on July 03, 2009 — Last Comment: 11:04 PM GMT on July 05, 2009

	Arctic sea-ice update

Posted by: sullivanweather, 12:48 PM GMT on July 01, 2009

**Updated with data to July 2nd**

Julian Day 178

------- Extent (km^2)----Difference (km^2)
2003 – 10,259,844……..……….-62,969
2004 – 10,179,531……..……….-46,719
2005 – 9,761,094……..……….-83,281
2006 – 9,526,719……..……….-58,281
2007 – 9,743,750………………-79,844
2008 – 9,992,344………..…….-62,061
2009 – 10,024,688………..…….-36,718

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Julian Day 179

------- Extent (km^2)----Difference (km^2)
2003 – 10,198,281……..……….-61,563
2004 – 10,155,156……..……….-24,375
2005 – 9,704,688……..……….-56,406
2006 – 9,435,625……..……….-91,094
2007 – 9,664,844………………-78,906
2008 – 9,949,844………..…….-42,500
2009 – 9,964,844………..…….-59,844

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Julian Day 180

------- Extent (km^2)----Difference (km^2)
2003 – 10,123,281……..……….-75,000
2004 – 10,138,125……..……….-17,031
2005 – 9,667,031……..……….-37,657
2006 – 9,366,563……..……….-69,062
2007 – 9,545,156………………-119,688
2008 – 9,870,781………..…….-79,063
2009 – 9,887,969………..…….-76,875

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Julian Day 181

------- Extent (km^2)----Difference (km^2)
2003 – 10,047,813……..……….-75,468
2004 – 10,102,656……..……….-35,469
2005 – 9,640,938……..……….-26,093
2006 – 9,314,063……..……….-52,500
2007 – 9,432,188………………-112,968
2008 – 9,783,438………..…….-87,343
2009 – 9,811,406………..…….-76,563

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Julian Day 182

------- Extent (km^2)----Difference (km^2)
2002 – 10,043,906……..……….-9999
2003 – 9,967,031……..……….-80,782
2004 – 10,092,969……..……….-9,687
2005 – 9,615,469……..……….-25,469
2006 – 9,238,594……..……….-75,469
2007 – 9,288,906………………-143,282
2008 – 9,722,656………..…….-60,782
2009 – 9,722,813………..…….-88,593

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Julian Day 183

------- Extent (km^2)----Difference (km^2)
2002 – 10,007,813.…..……….-36,093
2003 – 9,895,938……..……….-71,093
2004 – 10,060,625……..……….-32,344
2005 – 9,556,719……..……….-58,750
2006 – 9,159,063……..……….-79,531
2007 – 9,126,875………………-162,031
2008 – 9,645,000………..…….-77,656
2009 – 9,620,313………..…….-102,500

(*denotes extrapolated figure)

Sea-ice notes this week:

Weekly melt rate (6/21-28)

2009 – 56,429km^2
2008 – 62,411km^2
2007 – 79,129km^2
2006 – 87,969km^2
2005 – 68,951km^2
2004 – 56,518km^2
2003 – 57,679km^2

The melt rate for 2009 has slowed over the last week with an average rate of decline of 56,429km^2. This is likely due to the extensive cloud cover over the arctic in the western hemisphere. Near average to slightly below average temperatures is also aiding in this reduced melt rate, despite much of the ice edge consisting of first year ice.

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During the period of Julian Day 178-183 the year 2004 has an extremely slow melt rate relative to all years in the JAXA record. The 23,781km^2/day melt rate of 2004 during this period is 17,088km^2/day less than the runner-up 2005, which has a melt rate of 40,869km^2/day. Conversely, the year 2007 has a melt rate of 123,375km^2/day over the same period.

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Pics from the cryosphere

Fig.6 - Melt ponds forming on the Greenland ice cap as seen from space.

Fig.6a - Weakening shorefast ice along the Siberian coast.

Extent difference

Fig.7 - Difference in sea-ice extent between 2009 and recent years.

*Data retrieved from JAXA

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Current watches, warnings and advisories.

Fig.10 - Current watches, warning and advisories issued by the National Weather Service. Courtesy of NOAA.

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Forecast Discussion

Synopsis - Issued - 7/1 @8:45am

Deep upper level low spinning over the lower Great Lakes region will remain in place over the next 24 hours before opening as a negatively tilted trough on Thursday and lifting, finally, by Friday. Most, if not all, of the region will see some wet weather before this feature moves away but the areas from eastern New York to western New England stand the best chances for flooding rainfall. This first lobe of cut-off low pressure within a much broader overall longwave trough will be east of the region this holiday weekend with drier northwesterly flow from the Canadian Prairies and mainly fair weather with mild temperatures. Unfortunately, the second lobe of cut-off low pressure will rotate into the Northeast to begin next week with showers and thunderstorms increasing in coverage once again. This time, however, the system looks a bit more progressive and should press on into the Atlantic by the middle of next week.

Short-term - Issued - 7/1 @8:45am

The calendar may look different this morning but the view out the window sure hasn’t changed, with gray skies covering much of the Northeast. The most active weather is associated with a cluster of heavy showers and thunderstorms over southeastern southern New England and near-shore waters. Elsewhere, it’s fairly quiet. A few scattered showers are dotting the landscape over the central Pennsylvania ridge tops, along the shore of Lake Erie and across New Hampshire and Maine. Where precipitation isn’t falling the sun is scarce, aside from north of the Finger Lake region in New York. In fact, much of the area from northeast Pennsylvania to western New England has been socked in with thick fog, especially the higher terrain and river valleys. Temperatures this morning are generally in the 60’s with some 50’s confined to the normally colder inland locales and higher terrain.

With a more extensive cloud cover over the region today and weaker shortwave disturbances rotating through, shower and thunderstorm activity won’t be nearly as widespread as yesterday. Large scale ascent will still be present as the region will still lie in the favorable left exit region of an 80-90kt jet streak moving off the Mid-Atlantic Coast, the aforementioned shortwave passage and overall cyclonic flow through all levels of the atmosphere. These should all conspire to produce a blossoming area of precipitation as daytime heating becomes more of a factor by late morning. Enough sun should manage to break out to modestly destabilize the atmosphere by this afternoon, as indicated by progged CAPE values of 500-1,200J/kg, a touch lower than yesterday but more than adequate to fire convection. As for severe chances, winds aloft are lower than yesterday as is effective shear, which will only run 25-30kts. While not impressive for widespread severe weather a few stronger cells may bow into mini-line segments capable of damaging winds. Freezing levels are slightly lower than yesterday but given lower mid-level lapse rates than yesterday, storms won’t be as vertically structured. Expect cloud tops to top out in the 20-22,000’ range with VIL’s in the 30’s. Main areas for development will be across southern New Hampshire to western Maine, ahead of the weak shortwave rotating up the New England coast this morning, and across northeastern Pennsylvania to northern New Jersey, eastern New York and western New England, the areas hit hardest yesterday. This secondary area of enhanced precipitation will be due to the shortwave currently moving across central Pennsylvania. Expect the showers falling this morning to increase in coverage and intensity, eventually overspreading the aforementioned areas this afternoon. This is also the region that has been hit hardest by all the rainfall received during the month of June, so the ground is plenty saturated. Precipitable water contents are running in the 1.2-1.4” range, so the atmosphere is plenty moist. As seen yesterday given a similar set-up to today, training cells are possible and with winds aloft slightly slower, storm movement will follow suit. This combination of factors could lead to flash flooding of smaller creeks and streams, as well as poor draining and low-lying areas. Yesterday several areas saw localized 2-3” rainfall amounts and those can be replicated this afternoon. Basin wide rainfall averages should range from a quarter to half an inch so main stem rivers will simply continue running above climatology. To the west, under the core of the upper level low, activity will be more scattered, with pulse-type convection forming along weak convergence lines provided by cyclonic flow and naturally occurring boundaries around the lakes. Temperatures today will rise into the 70’s for most areas, though regions that receive early rainfall or remain socked in with low clouds and fog may hold in the 60’s. This is especially true across the higher terrain and along the immediate lake shores.

The upper level low finally begins to pivot eastwards tonight after spending a good 48 hours over Lake Huron and southern Ontario. In doing so the trough axis will begin to tilt negative and an area of low pressure will form along the coastline as a stronger shortwave rounds the base of the trough. This enhanced convergence/lift with spawn an intensifying area of showers and thundershowers along the coastal plain that will lift north-northeast as the night progresses, eventually encompassing much of New Jersey, eastern Pennsylvania, southern New England and southeastern New York. Rainfall within this band may be locally heavy, with amounts approaching and exceeding one inch. Elsewhere, much of the afternoon convection will taper with the loss of insolation during the evening hours. Any lingering showers should be located under the upper low itself over western/central Pennsylvania and across northern New England where weak shortwave energy will be passing by. Once again, fog will be a problem into the overnight across a wide swath of the region. Lows will fall back into the 60’s for most areas with a few more 50’s showing up as cooler air slowly bleeds in under the trough.

The area of low pressure slowly lifts north through eastern New York and New England during the day on Thursday with rain and thundershowers accompanying it. Cloud cover will be even more extensive tomorrow across the eastern half of the region with the significant surface low moving through, further limiting instability. So it will be rain without the thunder for most but don’t be fooled by the lack of clamoring by nature. Rain will fall quite heavy at times, leading to ponding of water and minor flash flood concerns. Further west, under the opening upper low, pop-up showers and thunderstorms due to diurnal heating will be present, but more isolated in coverage. High will once again only climb into the 60’s and 70’s.

Mid/long-term - coming later

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Radar: Northeast Region Loop

NE radar

Fig.11 - Radar loop of the Northeast region. Courtesy of Weather Underground.

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Local SST's

Fig.12 Sea-surface temperatures off the Northeast Coast. Courtesy of NOAA.

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All hits.

.

Unique hits.

My weather dragon!

Summer afternoon along the Delaware

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Updated: 11:40 PM GMT on July 03, 2009

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	Strong to severe storms today/Arctic sea-ice watch

Posted by: sullivanweather, 6:04 AM GMT on June 30, 2009

**Updated with data to June 28th**Julian Day 169 ------- Extent (km^2)----Difference (km^2)2003 – 10,809,844……..……….-78,7502004 – 10,685,156……..……….-67,1882005 – 10,362,188……..……….-66,8752006 – 10,228,438……..……….-57,0312007 – 10,450,469………………-72,0312008 – 10,542,500………..…….-70,4692009 – 10,603,125………..…….-68,594-------Julian Day 170 ------- Extent (km^2)----Difference (km^2)2003 �...

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Updated: 12:32 PM GMT on June 30, 2009

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	Severe weather likely today

Posted by: sullivanweather, 3:35 PM GMT on June 26, 2009

Fig.2 - USDA plant hardiness zone map of the eastern United States circa 1990. Credit: USDAGarden SeriesBlog 1: Planning the GardenBlog 2: Cool season cropsBlog 3: Companion PlantingBlog 4: Container GardeningBlog 5: Warm Season Crops(1)___________________________________________________________Soil Conditions**Please note**These soil condition charts are self-updating and occasionally display corrupted data (more often than not lately). Soil moisture and anomalies...