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CanisLupusArctos · 03-02-2007, 01:12 PM

It's hard to tell how much snow has actually fallen. On Black Cat it's been snowing heavily since about 2:30 this morning but there's barely any on the porch or in the yard.

This is due to the wind that has been increasing out of the east all morning, and is now averaging 22 from the ESE, gusting to 31. Some parts of the yard are blown clear, down to bare earth, while a 2-foot snowdrift lies adjacent. Needless to say the snow is getting abnormally deep wherever it can get out of the wind.

The melted precip for this morning is a scant 0.13 inches. I need to check that for validity because I've been having problems with my rain gauge heater and may need to install a better one. An inspection of the guage will tell me if it's a problem with the heater or if the wind is preventing the snow from resting in the gauge.

It's a much more powerful storm than what hit on Feb. 14 at this location. There is a much steadier wind. That storm produced a very gusty wind with many lulls and one peak at 39 mph... but this one has been a steady wind that's already hit 30+ several times... peaking at 33.

Color-coded radar and surface observations both confirm rain south of Concord. In the last hour heavy sleet has been hitting the east windows here, but at 1 pm there is still plenty of snow coming down. It is blowing and drifting heavily and creating a havoc on the roads.

At last check Belmont was the only town in the Lakes Region above freezing... and the NHDOT stations along I-93 are showing temps actually warmer in Woodstock than in Ashland.

The reason the snow held on as long as it did in the Lakes Region was most likely evaporative cooling... for several hours last night there was snow aloft and the weak moonlight showed it, but there was none in the floodlights down at this level. A Medical helicopter flew over at an extremely low altitude (about 500 feet AGL, 1000 feet alt.) around midnight, serving as an indicator of the level the snow was reaching since they usually fly only when or where they can see. For several hours the snow was evaporating into the air, cooling it the same way your skin feels chilly when water is evaporating off of it. When the air finally became saturated with humidity around 2:30 am, it stopped accepting any more evaporation and the snow was able to reach the ground... but the temperature had fallen well into the 20s.

Still a few more hours left on this storm.

Here's a weather demo you can do in a storm like this: Find a bottle with a screw-cap that becomes air-tight. (Empty Coke bottle should work fine.) Wait for the barometer to bottom out, (or sometime this afternoon) and close it up. Wait for the barometer to rise back up again (tomorrow, or better yet Tuesday when we'll see some arctic high pressure come back in here) and it should hiss when you open it.

CLA

03-02-2007, 01:12 PM	#155
CanisLupusArctos Senior Member Join Date: Jan 2007 Location: Center Harbor Posts: 1,049 Thanks: 15 Thanked 472 Times in 107 Posts	Hard to tell... It's hard to tell how much snow has actually fallen. On Black Cat it's been snowing heavily since about 2:30 this morning but there's barely any on the porch or in the yard. This is due to the wind that has been increasing out of the east all morning, and is now averaging 22 from the ESE, gusting to 31. Some parts of the yard are blown clear, down to bare earth, while a 2-foot snowdrift lies adjacent. Needless to say the snow is getting abnormally deep wherever it can get out of the wind. The melted precip for this morning is a scant 0.13 inches. I need to check that for validity because I've been having problems with my rain gauge heater and may need to install a better one. An inspection of the guage will tell me if it's a problem with the heater or if the wind is preventing the snow from resting in the gauge. It's a much more powerful storm than what hit on Feb. 14 at this location. There is a much steadier wind. That storm produced a very gusty wind with many lulls and one peak at 39 mph... but this one has been a steady wind that's already hit 30+ several times... peaking at 33. Color-coded radar and surface observations both confirm rain south of Concord. In the last hour heavy sleet has been hitting the east windows here, but at 1 pm there is still plenty of snow coming down. It is blowing and drifting heavily and creating a havoc on the roads. At last check Belmont was the only town in the Lakes Region above freezing... and the NHDOT stations along I-93 are showing temps actually warmer in Woodstock than in Ashland. The reason the snow held on as long as it did in the Lakes Region was most likely evaporative cooling... for several hours last night there was snow aloft and the weak moonlight showed it, but there was none in the floodlights down at this level. A Medical helicopter flew over at an extremely low altitude (about 500 feet AGL, 1000 feet alt.) around midnight, serving as an indicator of the level the snow was reaching since they usually fly only when or where they can see. For several hours the snow was evaporating into the air, cooling it the same way your skin feels chilly when water is evaporating off of it. When the air finally became saturated with humidity around 2:30 am, it stopped accepting any more evaporation and the snow was able to reach the ground... but the temperature had fallen well into the 20s. Still a few more hours left on this storm. Here's a weather demo you can do in a storm like this: Find a bottle with a screw-cap that becomes air-tight. (Empty Coke bottle should work fine.) Wait for the barometer to bottom out, (or sometime this afternoon) and close it up. Wait for the barometer to rise back up again (tomorrow, or better yet Tuesday when we'll see some arctic high pressure come back in here) and it should hiss when you open it. CLA Last edited by CanisLupusArctos; 03-02-2007 at 02:03 PM.