Vencore Weather
17Apr/15Fri

2:30 PM | Global sea ice areal extent running at slightly above-normal levels

antarctic_sea_ice_interactive
[Yellow line represents the year-to-date Southern Hemisphere sea ice areal extent compared to all other years going back to 1979; data courtesy University of Illinois "cryosphere"; NOAA/NCEP Snow and Ice Data Center]

Discussion

Overall Summary
Southern Hemisphere sea ice areal extent continues to run near record high levels in the satellite data era (circled area above) for this time of year in records going back to 1979 whereas the Northern Hemisphere continues to run near record low levels in the same comparison time period (circled area on bottom plot). Overall, the global sea ice areal extent is currently running slightly above-normal at just under half a million square kilometers above the 1979-2008 mean (below).

global_daily_ice_area_withtrend
[red line represents global sea ice areal extent compared to the 1979-2008 normal as represented by the “zero” line; data courtesy University of Illinois "cryosphere"; NOAA/NCEP Snow and Ice Data Center]

Southern Hemisphere Sea Ice
The rather remarkable period of consistently higher-than-normal sea ice areal extent in this part of the world actually began a few years ago. Back in 2011, the southern hemisphere sea ice areal extent was still at below-normal levels, but it has surged in recent years to the current 1.2 million square kilometers above the 1979-2008 mean.

Northern Hemisphere Sea Ice
The northern hemisphere sea ice areal extent is still below-normal relative to all years going back to 1979 although it is well above the lowest point set during 2012 and even above levels seen earlier this year. The northern hemisphere sea ice areal extent is currently 0.8 million square kilometers below-normal using the base period of 1979-2008 for comparison. The northern hemisphere sea ice areal extent has leveled off in the past 10 years or so at below-normal levels after dropping consistently from the mid 1990’s to the middle of the last decade. In the time period before the mid 1990’s, the sea ice areal extent was generally above-normal dating back to 1979.

The directional shift in the sea ice areal extent trendline that developed during the mid 1990’s in the northern hemisphere correlates quite well with a northern Atlantic Ocean sea surface temperature cycle that is tracked by meteorologists through an index called the Atlantic Multidecadal Oscillation (AMO). Indeed, Atlantic Ocean sea surface temperature anomalies play a critical role in the overall northern hemisphere sea ice areal extent. The AMO index flipped in phase during the mid 1990’s from negative (cold) to positive (warm) and the sea ice areal extent trendline changed direction right around that point in time.

The Atlantic Ocean is just recently showing signs of a long-term temperature phase shift back to cold and if that trend continues over the next couple of years then the northern hemisphere sea ice areal extent is quite likely to return to the above-normal levels seen prior to the mid 1990’s. (Click here for more information on the potential significant temperature phase shift in the Atlantic Ocean: http://vencoreweather.com/2015/03/22/1230-pm-the-atlantic-ocean-is-showing-signs-of-a-possible-significant-long-term-shift-in-temperatures-from-warm-to-cold/).

arctic_sea_ice_interactive
[Yellow line represents the year-to-date Northern Hemisphere sea ice areal extent compared to all other years going back to 1979; data courtesy University of Illinois "cryosphere"; NOAA/NCEP Snow and Ice Data Center]

Paul Dorian
Vencore, Inc.

Filed under: Climate Info Comments Off
17Apr/15Fri

7:00 AM | Weekend looking pretty nice with warm, dry weather on Saturday and then cooler, but dry conditions for Sunday…significant rain event likely on Monday

6-Day NYC Forecast

Today

Mostly cloudy, breezy, mild, an occasional shower, maybe even an isolated afternoon thunderstorm, much of the time will be rain-free, highs in the mid-to-upper 60’s

Tonight

Mainly cloudy early with a lingering shower possible then partly cloudy late, mild, lows by morning not far from 55 degrees

Saturday

Mostly sunny, breezy, quite mild, low-to-mid 70’s

Saturday Night

Partly cloudy, turning colder late, mid 40’s

Sunday

Mainly sunny, noticeably cooler, near 60 degrees

Monday

Potential for a heavy rain event with cool conditions, upper 50’s

Tuesday

Partly sunny, mild, chance for showers, low-to-mid 60’s

Wednesday

Mostly sunny, cooler, near 60 degrees

Discussion

A weak frontal system is approaching the eastern states today and it is generating scattered shower activity which will continue into early tonight, perhaps there will even be an isolated afternoon thunderstorm. The weekend looks quite nice with warm, dry conditions on Saturday and then cooler, but still dry weather on Sunday. A significant rain event is likely in the NYC metro region region late Sunday night and Monday as the overall weather pattern begins a transition to colder-than-normal weather which will be the dominate theme in the eastern two-thirds of the nation as we progress through the latter stages of April.

Filed under: NYC Comments Off
17Apr/15Fri

7:00 AM | Warm, dry conditions on Saturday…cooler Sunday…significant rain event on Monday

6-Day Philly Forecast

Today

Mostly cloudy skies this morning and then partial sunshine for the mid-day and afternoon hours mild, an occasional shower and perhaps even an isolated afternoon thunderstorm, but most of the time will be rain-free, highs not far from 70 degrees

Tonight

Mainly cloudy early with a lingering shower possible, partly cloudy late, mild, lows by morning not far from 50 degrees

Saturday

Mostly sunny, a bit of a breeze, quite mild, mid-to-upper 70’s

Saturday Night

Partly cloudy, turning colder late, low-to-mid 40’s

Sunday

Mainly sunny, noticeably cooler, low 60’s

Monday

Potential for a heavy rain event with cool conditions, low 60’s

Tuesday

Partly sunny, seasonal, chance for showers, mid 60’s

Wednesday

Mostly sunny, cooler, near 60 degrees

Discussion

A weak frontal system is approaching the eastern states today and it is generating scattered shower activity this morning in the Mid-Atlantic region and there can be isolated afternoon thunderstorms. The weekend looks quite nice with warm, dry conditions on Saturday and then cooler, but still dry weather on Sunday. A significant rain event is likely in the Philly metro region late Sunday night and Monday as the overall weather pattern begins a transition to colder-than-normal weather which will be the dominate theme in the eastern two-thirds of the nation as we progress through the latter stages of April.

Filed under: PHL Comments Off
17Apr/15Fri

7:00 AM | Weekend starts off real well and then goes downhill…significant rain event likely on Sunday night/early Monday

6-Day DC Forecast

Today

Partly sunny skies, quite mild, an isolated shower and maybe an afternoon thunderstorm, most of the day will be rain-free, highs in the mid 70’s

Tonight

Mainly cloudy early with a lingering shower possible then partly cloudy late, mild, lows by morning in the mid 50’s

Saturday

Mostly sunny, a bit of a breeze, quite mild, upper 70’s

Saturday Night

Partly cloudy, turning colder late, upper 40’s

Sunday

Increasing clouds, noticeably cooler, rain possible late in the day and at night, mid 60’s

Monday

Periods of rain in the morning, lingering showers in the afternoon, mild, upper 60’s

Tuesday

Partly sunny, mild, chance for a shower, upper 60’s

Wednesday

Mostly sunny, cooler, low 60’s

Discussion

A weak frontal system is approaching the eastern states today and it is generating scattered showers in the Mid-Atlantic region this morning - perhaps there will be an isolated thunderstorm this afternoon. The weekend starts off real well with warm, dry conditions on Saturday, but then Sunday turns cooler along with increasing clouds. A significant rain event is likely in the DC metro region during Sunday night and early Monday as the overall weather pattern begins a transition to colder-than-normal weather which will be the dominate theme in the eastern two-thirds of the nation as we progress through the latter stages of April.

Filed under: WMA Comments Off