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MaineJayhawk

NNE Autumn 2013 Thread

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Great disco by Mr. Taber in the AFD this afternoon on the upslope potential with this cold shot over the weekend:

"On Saturday...mid/upper level trough sharpens across our County Warning Area with enhanced 850 to 500mb moisture developing associated with strong positive vorticity advection and good 850 to 700mb fgen forcing with front. Secondary cold front drops from northwest to southeast across our County Warning Area between 18z and 03z Saturday...with sharply falling 850 mb/925mb temperatures. Given good surface convergence...plenty of 850 to 500mb moisture...and developing upslope follow from 925mb to 850mb behind surface feature after 21z...expecting a period of accumulating snowfall across the Green Mountains and northern dacks late Saturday afternoon into Saturday night. In addition...as prognosticated 850 mb temperatures drop between -9c and -11c by 12z Sunday...expect additional moisture to be squeeze out from cold air advection. Will mention likely probability of precipitation across the mountains to cover this potential. Given...the short 3 to 6 hour window of favorable relative humidity/follow and low level forcing...overall snowfall above 1500 feet will be 1 to 3 inches...with some light amounts possible across the valleys on Sat night. Temperatures will be tricky on Sat/Sat night...especially with sharp thermal gradient moving from northwest to southeast across our County Warning Area. I would anticipate falling temperatures across the dacks/slv and parts of the northern Green Mountains after 18z Saturday...with values dropping into the 20s dacks and 30s Green Mountains meanwhile...CT River Valley will see highs in the 50s associated with downslope southwest follow on Sat...with middle/upper 40s in the cpv. Overnight temperatures will drop into the middle/upper teens mountains to M/u 20s valleys by Sunday morning. &&

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Congrats? :bag:

I don't win with radiational cooling so I need to pick battles I can win. ;) I actually like these wedge days this time of year. If it's going to be cloudy and rainy it may as well be miserable in every facet. I missed that weenie cold spot in E-C NH on the ME border before I posted though...quite a few U30s there.

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I don't win with radiational cooling so I need to pick battles I can win. ;) I actually like these wedge days this time of year. If it's going to be cloudy and rainy it may as well be miserable in every facet. I missed that weenie cold spot in E-C NH on the ME border before I posted though...quite a few U30s there.

Your area for CAD is remarkable. That's not a bad thing to excel at...heavy heavy snow preservation when we've got white stuff.

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I don't win with radiational cooling so I need to pick battles I can win. ;) I actually like these wedge days this time of year. If it's going to be cloudy and rainy it may as well be miserable in every facet. I missed that weenie cold spot in E-C NH on the ME border before I posted though...quite a few U30s there.

 

This is when I become envious. A contractor friend just bought a place in Madison NH to renovate. I told him to prepare for a long winter...lol.

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would love to be up here tomorrow for mount washington

Today:

In and out of the clouds under mostly cloudy skies early, becoming in the clouds w/ rain, mainly later. Wind chills 15-25 degrees.

Highs: Upper 30s°F

Wind: W shifting SW 30-45 mph increasing to 55-75 mph w/ higher gusts

Tonight:

In the clouds w/ rain, possibly heavy at times. Wind chills 20-30 degrees.

Lows: Rising to around 40°F

Wind: SW 65-85 mph increasing to 90-110 mph w/ higher gusts

Tomorrow:

In the clouds w/ rain, mainly early, and possibly heavy at times. Wind chills 15-25 degrees.

Highs: Falling into upper 30s°F

Wind: W 90-110 mph w/ higher gusts

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I don't win with radiational cooling so I need to pick battles I can win. ;) I actually like these wedge days this time of year. If it's going to be cloudy and rainy it may as well be miserable in every facet. I missed that weenie cold spot in E-C NH on the ME border before I posted though...quite a few U30s there.

 

IZG FTW!

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Interesting precip spread today but pretty classic too...strong SW flow downsloping into the Champlain Valley in the vicinity of BTV, then precip comes on heavily again from the Spine and east. We've been raining a steady 0.1/hr for 3-4 hours and BTV is only reporting clouds at this point.

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Interesting precip spread today but pretty classic too...strong SW flow downsloping into the Champlain Valley in the vicinity of BTV, then precip comes on heavily again from the Spine and east. We've been raining a steady 0.1/hr for 3-4 hours and BTV is only reporting clouds at this point.

 

Yeah we have seen off and on rains in Winooski, but the winds have already gusted to around 35 today. It is a little nasty for the trick or treaters.

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Yeah we have seen off and on rains in Winooski, but the winds have already gusted to around 35 today. It is a little nasty for the trick or treaters.

You will see far higher winds than I will...if experience serves me right, here in the lower east slope elevations we'll be protected under a surface inversion. I've seen many wind advisories lead to 5-10mph gusts here in town, but from 1500ft and up it's ripping. Now, NW winds are a different story, but southerly direction wind advisories don't seem to pan out locally. But it's all about knowing your local climate and what to expect in certain situations.

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You will see far higher winds than I will...if experience serves me right, here in the lower east slope elevations we'll be protected under a surface inversion. I've seen many wind advisories lead to 5-10mph gusts here in town, but from 1500ft and up it's ripping. Now, NW winds are a different story, but southerly direction wind advisories don't seem to pan out locally. But it's all about knowing your local climate and what to expect in certain situations.

 

NW you get the downslope assist. Similar to how the rain shadowed areas of the Whites can roar on a strong SE LLJ.

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The 18z runs of the NAM and GFS both bring a nearly 80 kt wind max over the area at 1000 feet. Probably a little on the aggressive side, but still impressive.

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NW you get the downslope assist. Similar to how the rain shadowed areas of the Whites can roar on a strong SE LLJ.

 

Yeah it depends on the event and Froude numbers and stuff like that.  Its interesting that we can get the downslope assist with wind, but precipitation can still be robust on NW flow (I sometimes chalk that up to precipitation forming over the Spine, getting blown the 3 miles downwind into the lower elevations of town).  Sometimes the two go hand in hand (downslope wind and drying precip) but other times we'll still be snowing/precipitating hard while those strong winds move down the lee (east) side of the Spine.  The shadowing seems more pronounced on SE flow for whatever reason... when I lived in Jonesville (low elevation, western slope location), anytime there was a SE flow at H85, we'd get some huge winds and next to no precip, lol.  It would be snowing 1"/hr at J.Spin's place a few miles away but on the eastern side of the Spine axis, while I was looking at patches of blue sky and huge downslope winds. 

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I love new toys. Just found out about this website that displays some of my favorite ensemble data (anomalies and percentiles).

 

post-44-0-04164300-1383259137_thumb.png

 

This is the NAEFS forecast for 12z tomorrow. The shading indicates percentile based on climatology (21 days centered at 00z on the date of the map). Climatologically speaking, these types of winds at 850 mb are maxed out or have never been experienced over a large portion of the region this time of year (basically everything in red).

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I love new toys. Just found out about this website that displays some of my favorite ensemble data (anomalies and percentiles).

 

attachicon.gif10-31-2013 6-37-26 PM.png

 

This is the NAEFS forecast for 12z tomorrow. The shading indicates percentile based on climatology (21 days centered at 00z on the date of the map). Climatologically speaking, these types of winds at 850 mb are maxed out or have never been experienced over a large portion of the region this time of year (basically everything in red).

 

Impressive... what's the scale of the percentiles on that?

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Impressive... what's the scale of the percentiles on that?

 

Terrible scientist not including the scale. Shading starts at 90th percentile, brownish yellow is 99.5, and red is max.

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NBD it's cool.

 

It might be one of those experimental things that's not ready for public release yet. There isn't much regarding model data that we don't allow free use of though.

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It might be one of those experimental things that's not ready for public release yet. There isn't much regarding model data that we don't allow free use of though.

I saw some new satellite products being tested. The idea sounds awesome regarding fog imagery, but I think WFOs over on the west coast and Hawaii are testing it.

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I saw some new satellite products being tested. The idea sounds awesome regarding fog imagery, but I think WFOs over on the west coast and Hawaii are testing it.

 

GOES-R stuff? Honestly any improvements in fog detection would be awesome, as it's perpetual any time of year up here.

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GOES-R stuff? Honestly any improvements in fog detection would be awesome, as it's perpetual any time of year up here.

 

 

Yeah that's it. It looked pretty cool.

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