NNE Fall Thread

[OceanStWx]

8 hours ago, MarkO said:

FEMA may have elevation profiles of the river you're on. If so, and if it was me, I'd build above the 500 year flood elevation. If not, I'd go 3 feet above the previous flood. 

I’m pretty sure our hydrologist looked last night and there weren’t any flood maps for that part of the state. Also I can’t remember now which river (may have been the Peabody?) but we did hit a couple 500 year flows in this event.

[alex]

Wow, that's incredible. I did look for FEMA maps - they exist but don't have much data, and the designated 100-year flood zone covers part of my land (I'm on 32 acres) but nowhere near the house... I've been told it's not very reliable, however. 

[tamarack]

On ‎11‎/‎2‎/‎2017 at 8:09 AM, wxeyeNH said:

Alex,  my guess is that it takes an exponential amount of rain as rivers like yours rise higher and higher.  I been to your house several times and  it seems the "flood plain"  is wide so that the river can spread out at least right at your location.  So to get a couple more feet of water right at your property the river would have to get really wide.  Just a complete guess.  The other thing I suggested to you on the phone is to call the Mt Washington.  They must have long time employees or locals that can judge how this flood on the Ammo compared to others.  They can tell by how high the water came over the access road to the resort...

That's probably what I would've recommended, until reading Chris's data.  Looks like this event came within an inch or two of matching 3/53, the #4 peak.

"Exponential" is how I'd describe the worst-case snowmelt/rainfall of 3/31-4/1/87, which I've seen described as a 100 year, and sometimes 500 year event.  Below are the top 5 peak flows for both Carrabasset and Sandy plus some comments on the differences of events.  Intense tropical downpours kickstart the steeper 'Basset watershed, while longer increases from snow plus rain hit both rivers much the same - prior to Irene, their top 3 were identical, and all rain-snowmelt events.

Carrabasset (cfs and date - records 1926 on)
50,700    4/1/87
31,600    8/29/11  Irene
30,800    3/19/36
30,400    3/27/53
25,600    9/17/32  probably tropical.  Farmington's 3rd largest rain event - 6.63"
The Dec 1969 storm peaked at 19,700, 19th highest.  The June 1998 downpour brought 17,900, for 26th.
 

Sandy (records 1929 on but missing 80-86)
51,100    4/1/87
38,600    3/19/36
36,900    3/28/53
29,100    12/28/69   Farmington's largest precip event.  If 9.96" is accurate (I think it 2-3" high), the storm brought 15" snow then 8"+ RA.
28,800    6/15/98    #2 rain event, 7.89"  A 48-hour storm, not TC related, though obviously with tropical moisture included
That Sept 1932 drenching raised the Sandy to 15,400, not in its top 40.  Irene gave Farmington 4.34" (some unofficial Carrabasset Valley obs reached 8"), and the peak wasn't even the water year's top.  The graph shows +/-14,500.

[j24vt]

14 hours ago, Hitman said:

I go to alpine options in Warren.  They’re great.  Already done the couple hours of fitting, but can’t decide which boot I want to go with.  

The boot chooses you

 

[OceanStWx]

It's pretty awesome that PSU got some portable gauges up into the mountains as the event was starting. Otherwise, I don't think we would have had direct measurements of the heaviest rainfall.

I think they got one up around the Pemi Overlook and measured 6.66" even though when they placed the gauge it was already raining moderately and they estimate missing 0.33-0.50" of precip.

[wxeyeNH]

Heat wave coming to an end.  Note to self.   Cold air damming always overperforms in my area.

Yesterday's high  55F

Today's high as of 4pm.  62F.  Today wasn't CAD but we never were able to break into any clearing that was just south of us.  

Total 2 day rainfall.   .38"

 

 

[eyewall]

Some of the birches and other trees still have bright yellows in the CPV. Otherwise of course it is going to rust and brown to full leaf drop. Mt. Philo today:

[alex]

From our rescue... 

[J.Spin]

Based on the BTV NWS forecast discussion, it sounds like the end of the week bears watching with regard to wintry precipitation, and for folks who switch out tires there’s a reminder to get those snow tires on:

 

.LONG TERM /TUESDAY THROUGH FRIDAY/...

As of 355 AM EDT Saturday...More like Fall weather for this period with even a more wintry feel/look by the end of the period.

 

Broad cyclonic, zonal flow dominates through early Thu with the elongated surface high to keeps things relatively dry and cooler than normal.

 

Cold northern stream shortwave and strong cold front expected across the region late Thu/Fri. GFS Thu aftn/ngt while ECMWF Thu ngt-Fri with WPC going with GFS and 00z ECMWF a tad quicker than 12z run thus trending earlier.

 

These trends are key in the timing of showers and temperatures as the GFS would support rain to snow showers and squalls? possibly impacting thu evening commute for NY and possibly some of Nrn VT, whereas ECMWF would push threat into Thu Ngt for RW to SW. Again, leaning and compromising toward GFS with RW to SW for NY. 925mb temps are 0 to -12C on GFS and +2 to -6 on ECMWF by 00z Fri.

 

However, by 12z Fri both have -10 to -16C at 925mb then modifying already to -10 to -12C by 00z Sat. Most locales will not reach freezing Fri but model blends still had U30s/L40s, thus undercut substantially from there but still have above freezing in areas for collaboration with neighbors.

 

Chillest night of the year as well for Fri Ngt-Sat morning with lows likely in teens/20s.

 

A reminder...as we`re starting to see snow enter our forecasts, please get your snow tires installed sooner rather than later.

[powderfreak]

This morning.

Gotta start somewhere.

[eyewall]

Looks like a wind advisory is in place for the BTV region for gusts up to 50 mph this afternoon. 

[dendrite]

36.6F with some clouds this morn. Hoping for first flakes this week via some NW flow.

[adk]

2 hours ago, eyewall said:

Looks like a wind advisory is in place for the BTV region for gusts up to 50 mph this afternoon. 

Just took a run on the bike path. Winds are already pretty strong along the lake with decent sized breaking waves. I think I did about 7min/mile with the wind and 14 min/mile against the wind.

[OceanStWx]

Man @eekuasepinniW is missing some quality misery mist in his hood today. Just passed by Scoot’s place and now I’m having some Jon’s Roast Beef on my way through cleaning coop equipment.

Foliage is surprisingly still decent. Oaks are a good color with occasional pops of yellow with what looks like birch.

[dendrite]

1 hour ago, OceanStWx said:

Man @eekuasepinniW is missing some quality misery mist in his hood today. Just passed by Scoot’s place and now I’m having some Jon’s Roast Beef on my way through cleaning coop equipment.

Foliage is surprisingly still decent. Oaks are a good color with occasional pops of yellow with what looks like birch.

I will be doing that in a bit.

I noticed the foliage hanging on by the lake too when we did a damage our to Gilford early last week. It's mostly sticks at the casa except for some lingering brown oaks.

[eyewall]

Some of the Birches still had brilliant yellows over the last few days:

[wxeyeNH]

Fropa through.   .27"  since mist started yesterday afternoon.  Brisk NW wind is helping take down the last of the brown oak leaves.  Will we score the first flakes on Friday with the Arctic front?   Guess it's time to finally say goodbye to the marigolds that are still holding on and to turn off the outside water...

[powderfreak]

The plow guy came by and put the driveway stakes in today...another sign we are getting closer haha.

[Hitman]

3 hours ago, wxeyeNH said:

Fropa through.   .27"  since mist started yesterday afternoon.  Brisk NW wind is helping take down the last of the brown oak leaves.  Will we score the first flakes on Friday with the Arctic front?   Guess it's time to finally say goodbye to the marigolds that are still holding on and to turn off the outside water...

Turned off my water yesterday.  Hate that since I have to go into my crawl space.

[alex]

2 hours ago, powderfreak said:

The plow guy came by and put the driveway stakes in today...another sign we are getting closer haha.

I noticed here too yesterday that the town has put up stakes at the fire hydrants. Wasn't sure if it's a seasonal thing or just new stakes that I hadn't noticed before but it felt good to see. 60% chance of snow Thursday night and a low of 12 and high of 30 a day later. It's coming. ❄️

[eekuasepinniW]

7 hours ago, OceanStWx said:

Man @eekuasepinniW is missing some quality misery mist in his hood today. Just passed by Scoot’s place and now I’m having some Jon’s Roast Beef on my way through cleaning coop equipment.

Foliage is surprisingly still decent. Oaks are a good color with occasional pops of yellow with what looks like birch.

Get the roast beef with mayonnaise and garlic.  They have the most unexpectedly delicious mayonnaise.  I'm probably pushing close to 100 sandwiches there by now.

I went to the Dry Tortugas National Park today, as I have done 11 times now- probably my favorite day trip of all time.  At the top of Fort Jefferson, I was indeed very safe from miserymist:

 
Bush Key was open because the sooty terns weren't nesting, so for the first time I was able to walk the whole length. Near the end was a sailboat from Key West that broke free and beached itself during the hurricane.  Pretty amazing that it would drift 70 miles and manage to hit a 40 foot wide sandbar.  

It's a shame the sailboat photo is on my other camera, but here is a picture from as far down bush key as I felt like walking.  

[J.Spin]

Well, for the upcoming Thursday/Friday period that has been mentioned since last week, it sounds like there’s a lot more overall consistency in the models based on the BTV NWS forecast discussion.  It’s a bit too far out to really start seeing potential accumulation numbers in the forecast itself, but in terms of liquid, our point forecast suggests under a tenth of an inch.

 

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

As of 225 AM EST Tuesday...It took a while but the last several runs of all medium range models finally show some model to model and run to run consistencies with just some minor timing differences for Thu Ngt-Friday.

 

Northern stream shortwave develops surface low across Ontario and deepens bringing cold front through the North Country with some light precipitation and temperature profiles support snow.

 

Available moisture and precipitation amounts are limited but the tightly packed thermal gradient will remain something to watch for as there could be enough dynamical support to generate some snow squalls but the good news with regards to impacts, is that the timing of the front will move through overnight limiting the overall impact of any such squalls.

 

There’s also a system to watch for Sunday into Monday:

 

There are some differences come Sunday with Canadian and GFS with a stronger mid-level shortwave bringing chance of some scattered light precipitation...snow, rain/snow mixed or rain showers.

[J.Spin]

I was checking out the Killington Superstar Cam after reading MarkO’s comment in the ski thread, and was surprised to see what looked like natural snow falling as well:

 

 

Sure enough, on the radar you can see a finger of snowfall that’s made its way up into Central Vermont:

 

[wxeyeNH]

36.6/28F  Ceiling is lowering and thickening as radar shows precip just to the NW and W.  Will we get a few flakes or will this be virga?   Should know soon!

[eyewall]

Lady Aurora tried to appear for about 30 seconds over South Hero at 6:11pm EST this evening:

[Lava Rock]

12 hours ago, eyewall said:

Lady Aurora tried to appear for about 30 seconds over South Hero at 6:11pm EST this evening:

where is South Hero?

[J.Spin]

The latest update BTV NWS forecast discussion on tomorrow night’s potential snow is below – there’s some nice discussion of applying their snow squall forecast methodology:

 

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...

As of 329 AM EST Wednesday...Coldest airmass of the early winter season is poised to move across our cwa during this time period and a few of us who live at 44 degrees north latitude to experience winter are extremely excited. Models in very good agreement showing potent 5h energy diving southeast associated with digging mid/upper level trof...while sharp modified arctic boundary is approaching the SLV by 00z. This cold front will quickly sweep across our cwa on Thursday Night...with a period of rain/snow showers...along with a few embedded snow squalls...especially over northern NY/VT.

 

The locally developed snow squall parameter shows values 5-7 between 03-09z Friday...indicating good instability, moisture, and lift is present. NAM12/4km show sfc based CAPE values btwn 125 and 150 J/kg...with sharp convergence...and strong 925mb fgen forcing to enhance lift...while pw values range btwn 0.25 and 0.50. All these parameter support the idea of some embedded snow squalls associated with arctic boundary on Thursday Night...so have continued with +SW for northern NY into parts of central/northern VT. Initially boundary layer temps will support a mix of rain/snow in the valleys with progged snow levels around 2000 feet...before quickly crashing behind boundary. As quickly as snow level drop to the valley flow...deep layer moisture is rapidly shifting east and llvls are drying out on gusty west to northwest winds. Bottom line expect an inch or two of snow above 1000 feet and a dusting to maybe an inch in the valleys by early Friday morning. A few slippery spots are possible during the Friday morning commute with some black ice and snow covered roads.

 

 

And of course who wouldn’t enjoy that comment to start off the short term forecast:

 

...and a few of us who live at 44 degrees north latitude to experience winter are extremely excited.

[eyewall]

31 minutes ago, Lava Rock said:

where is South Hero?

Southern end of the Champlain Islands in the lake. 

[wxeyeNH]

2 hours ago, J.Spin said:

 

 

...and a few of us who live at 44 degrees north latitude to experience winter are extremely excited.

 

Im safely at 43.5N.  Green forcefield will be fully in effect Friday AM.  Will be fun to watch the temp fall as the sun rises.  I like when fropa's come through in the AM to see the reverse temp trend...

[adk]

6 hours ago, J.Spin said:

The latest update BTV NWS forecast discussion on tomorrow night’s potential snow is below – there’s some nice discussion of applying their snow squall forecast methodology:

 

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...

As of 329 AM EST Wednesday...Coldest airmass of the early winter season is poised to move across our cwa during this time period and a few of us who live at 44 degrees north latitude to experience winter are extremely excited. Models in very good agreement showing potent 5h energy diving southeast associated with digging mid/upper level trof...while sharp modified arctic boundary is approaching the SLV by 00z. This cold front will quickly sweep across our cwa on Thursday Night...with a period of rain/snow showers...along with a few embedded snow squalls...especially over northern NY/VT.

 

The locally developed snow squall parameter shows values 5-7 between 03-09z Friday...indicating good instability, moisture, and lift is present. NAM12/4km show sfc based CAPE values btwn 125 and 150 J/kg...with sharp convergence...and strong 925mb fgen forcing to enhance lift...while pw values range btwn 0.25 and 0.50. All these parameter support the idea of some embedded snow squalls associated with arctic boundary on Thursday Night...so have continued with +SW for northern NY into parts of central/northern VT. Initially boundary layer temps will support a mix of rain/snow in the valleys with progged snow levels around 2000 feet...before quickly crashing behind boundary. As quickly as snow level drop to the valley flow...deep layer moisture is rapidly shifting east and llvls are drying out on gusty west to northwest winds. Bottom line expect an inch or two of snow above 1000 feet and a dusting to maybe an inch in the valleys by early Friday morning. A few slippery spots are possible during the Friday morning commute with some black ice and snow covered roads.

 

 

And of course who wouldn’t enjoy that comment to start off the short term forecast:

 

...and a few of us who live at 44 degrees north latitude to experience winter are extremely excited.

Yea it really is a great set-up for squalls. Friday AM could be a real mess on roads as people aren't going to be ready for the very icy frozen road surface and are still on all-weather or summer tires. 

That said, if the squall was moving through at rushhour (either AM or PM) it would be so much worse. 

Shame the moisture is shifting east so fast (and it really is). This is a very good set-up for a 6+ event if that moisture held on a little longer.