Severe Wx & Flood Threat Through Tuesday

[kdxken]

I would think so...if it starts weakening, it's b/c it's outrunning the best upper level support...that's the only thing I can see killing it.  

'kay..thanks!

[weatherwiz]

I think that may happen... at least its out-pacing the cold front now by a decent bit.  Not sure where it is in relation to the short-wave and upper trough, though.

 

We also broke out into a decent bit of sunshine this afternoon and we are losing that as the sun goes down as we speak.

 

Instability is actually slightly higher though into western VT along with 30-35 knots of vertical shear and steep lapse rates so this line could last as it moves through a higher instability area...once it moves into eastern VT or western NH though I would expect more rapid weakening.  

[CoastalWx]

It's outrunning it, but it basically is its own cold front since it is generating a cold pool and strong convergence. What will kill it is loss of instability eventually. Shear still is good.

[weatherwiz]

the 18z NAM/GFS are so interesting...if that front even slows down by 2-3 hours it could be quite active.

[HoarfrostHubb]

Might get my first good show in a while tonight. It has been a long time

Eyewall, superb shot.

[powderfreak]

Instability is actually slightly higher though into western VT along with 30-35 knots of vertical shear and steep lapse rates so this line could last as it moves through a higher instability area...once it moves into eastern VT or western NH though I would expect more rapid weakening.  

 

Ahh, that makes sense.  The Champlain Valley also probably has better low level temps/dews to keep it going as well, and winds funnel in the valley between the 4,000ft terrain of the Adirondacks and Greens... adding possibly to some shear. 

 

East of the Greens/Spine we may already start to develop a weak near-surface inversion as the sun goes down, winds are calm, and breaks in the clouds. 

 

Not a whole lot of SVR reports though coming out of NY...a couple 1" hail reports and scattered tree damage which you never know exactly what that means.  It could just be dead branches falling or whole trees uprooted, lol.

[weatherwiz]

Ahh, that makes sense.  The Champlain Valley also probably has better low level temps/dews to keep it going as well, and winds funnel in the valley between the 4,000ft terrain of the Adirondacks and Greens... adding possibly to some shear. 

 

East of the Greens/Spine we may already start to develop a weak near-surface inversion as the sun goes down, winds are calm, and breaks in the clouds. 

 

Not a whole lot of SVR reports though coming out of NY...a couple 1" hail reports and scattered tree damage which you never know exactly what that means.  It could just be dead branches falling or whole trees uprooted, lol.

 

I thought perhaps hail would be more of a occurrence given the steep lapse rates/cold mid-level temps and increasing 0-6km shear values.  I guess helicity values being on the low side prevented strong enough updrafts to promote a larger threat. 

[Quincy]

Were there any severe hail reports out of W NY near Syracuse? Radar looked intense, but it might have been due to the proximity away from BGM and TYX seemed to have a much corser sampling. Weaker beam? I only observed some gusty winds (maybe up to 50mph) and a few bouts of small hail. Pretty sweet looking shelf cloud though, I posted a pic in the upstate NY thread.

[Typhoon Tip]

I think that may happen... at least its out-pacing the cold front now by a decent bit.  Not sure where it is in relation to the short-wave and upper trough, though.

 

We also broke out into a decent bit of sunshine this afternoon and we are losing that as the sun goes down as we speak.

 

Good questions to ask, actually.

 

There's no question there's plenty to work with given substantive mechanics with all these ludicrous DP around -

[cny rider]

We just had a good old fashioned summer storm here.

Abundant lightning, booming thunder, and a downpour. Nothing severe but lovely to see, hear and feel.

If there was any severe I suspect it was north of me, possibly Utica to Richfield Springs area.

[weatherwiz]

Just some more detailed thoughts on tomorrow I wrote up on my blog

 

Just one more day of high humidity to go as a cold front is slowly creeping towards the region.  Once the cold front pushes through the region sometime tomorrow, much more seasonable temperatures will arrive along with much lower humidity values.  In fact, a few nights later this week will give us temperatures feeling more like fall.  Before the cold front moves through though we may have to deal with more downpours and t'storms and some of these storms may be quite strong.  

 

The million dollar question right now regarding tomorrow is exactly when the cold front will slide through the region.  Currently, the projected timing of the cold front appears to occur at the time of day when conditions could be rather ripe for strong/severe t'storms, however, this window is very critical right now.  If the front slides through 3-4 hours later that what is currently modeled than the threat for strong/severe t'storms could be higher.  If the front moves through around the time the models are suggesting, the better threat may exist across RI and eastern MA.  If the front moves through even 2 hours quicker than what is modeled, than the threat for strong to severe storms would be extremely low region wide.

 

If past history is any indication, typically computer models are a bit too quick to move cold fronts through the region, especially when you have an amplifying trough and/or strong ridging out in the western Atlantic.  When looking at the overall synoptic pattern and the models handling of the evolution of the synoptic pattern over the next day, we see some strong ridging in the western Atlantic along with an amplifying trough allowing from winds in the mid to upper-levels of the atmosphere to work parallel with the cold front.  Typically this scenario would actually allow for a slower eastward progression of the cold front but this does not guarantee it.  Sometimes, short wave energy associated with the cold front and surface low will de-amplify and this could cause a disconnect between the trough and the cold front.  i.e. the cold front begins progressing east quicker than the trough.  This will have to be closely monitored throughout the remainder of the night and into the morning hours tomorrow.

 

Another issue we have to contend with will be cloud cover and instability, which always seems to be a cause for concern here.  Today, much of the region was socked in with overcast, although there were several breaks of sun across many locations.  Upstream there was a quite a bit of convection today and cloud debris continues to move into the region.  It's quite likely tomorrow there will be lots of cloud cover which will ultimately hold back instability values.  What does seem highly possible though is there are many breaks within the clouds allowing for pockets of stronger destabilization.  The more sun and stronger the heating, especially when coincident with a slower frontal passage, the better chance for strong to severe t'storms.  This will also have to be monitored in the morning hours.  

 

Winds aloft will also be fairly strong tomorrow with vertical shear values favorable for storm organization and longevity.  There also appears to be a decent amount of winds turning with height in the 0-3km levels with 0-3km helicity values perhaps exceeding 150-200 m2s2. 0-1km helicity values though are quite low, however, if surface winds back ahead of the cold front, these values will be much higher.  Temperatures in the mid--levels of the atmosphere will also be cooling, allowing for steepening mid-level lapse rates.  

 

Tomorrow, besides the threat for torrential downpours and isolted flash flooding, the potential will also exist for numerous t'storms with several becoming strong to severe.  However, the extent of the threat will all be determined by the timing of the front and if we can destabilize the atmosphere enough.  If we are able to get strong/severe t'storms the potential would be large hail and damaging winds.  

 

The potential will be monitored through the night and into the morning as the details start to become much more clear.

[eyewall]

Amazing shelf cloud over Lake Champlain! pics to come soon.

[free_man]

seeing the typical line split now, close to alb.   I'd be interested to see if the sw flank develops a bit more, maybe a few storms for CT later.

[weatherwiz]

seeing the typical line split now, close to alb.   I'd be interested to see if the sw flank develops a bit more, maybe a few storms for CT later.

 

I really would be shocked if we at least didn't see some sort of development during the overnight hours.  

[weatherwiz]

The 0z ALB/OK soundings are pretty impressive

[powderfreak]

Line is weakening a bit but heck of a lightning storm incoming and a solid gust front moving through...really hoping we don't lose power.  The wind is picking up and I've got visions of 3 days sans electricity like the July 19th event, lol.

[ineedsnow]

looks like it might be fun here in a couple hours if the line holds together

[weatherwiz]

looks like it might be fun here in a couple hours if the line holds together

 

There is between 300-500 J/KG of Cape in the -10C to -30C level and MUcapes running near 2,000 J/KG...I expect these values to hold with cooling 500mb temps so there should be another decent light show tonight for many.  In fact, you and I could be seeing lightning within the next 90 min

[SnowMan]

Any chance the storms make it here?

[free_man]

Any chance the storms make it here?

A rumble or two.  They're already almost fizzled.

[ice1972]

There is between 300-500 J/KG of Cape in the -10C to -30C level and MUcapes running near 2,000 J/KG...I expect these values to hold with cooling 500mb temps so there should be another decent light show tonight for many. In fact, you and I could be seeing lightning within the next 90 min

Nice.....love me some nocturnal convection....lol

[eyewall]

I need a fully manual DLSR but I did the best I could as it was getting dark so they are grainy as hell. I got a PM about posting unenhanced photos, which in the future I will do along with the enhanced versions, but these as is are very hard to see because again it was after sunset. This was Battery Park in Burlington, VT overlooking Lake Champlain.

 

 

[weatherwiz]

BEAUTIFUL!

[ice1972]

I need a fully manual DLSR but I did the best I could as it was getting dark so they are grainy as hell. I got a PM about posting unenhanced photos, which in the future I will do along with the enhanced versions, but these as is are very hard to see because again it was after sunset. This was Battery Park in Burlington, VT overlooking Lake Champlain.

Dude....these are tremendous shots....blur or no blur....excellent

[ineedsnow]

amazing pics

[weatherwiz]

Well the 0z NAM is really no faster or slower with the front.  

[joey2002]

Wow... incredible photos!!

[kdxken]

I need a fully manual DLSR but I did the best I could as it was getting dark so they are grainy as hell. I got a PM about posting unenhanced photos, which in the future I will do along with the enhanced versions, but these as is are very hard to see because again it was after sunset. This was Battery Park in Burlington, VT overlooking Lake Champlain.

Manual or programmed the ISO will need to be high in that low of light. A full frame DSLR and a fast lense will help but it's the nature of the beast. Nice photos anyway...

[Christina311]

Nice pictures!!!!!

[CoastalWx]

Great shots!