Upstate NY/North Country + adjacent ON, QC, VT: Meteorological fall is here

[FULLAUTO]

I thought this part addresses your question?

Yes, thank you. I'll keep checking for updates.

Teaser from Montague, NY 12-29-12

[kulaginman]

For the Western New Yorkers in this thread, it looks like the GGEM has caved to the more mundane model solutions regarding the potential for a single band SW flow event impacting the BUF metro area. The secondary trough has been less defined on more recent runs, and it doesn't lag behind the initial cold front as much. In other words, the flow turns to the NW/NNW much more quickly which won't allow for the development of an organized lake band.

The SREFs are indicating that there could be a period of upslope snowfall early Saturday morning which could coat the ground from the Boston Hills southward to the Chautauqua Ridge - certainly nothing abnormal for late November, but it'll get the folks in ski country excited anyway. This is the three-hour probability of >0.01" QPF for the period ending 12z Saturday:

One area that could do a little better, as noted in the above AFD, is the Chautauqua Ridge where there is some suggested potential for a Lake Huron connection that could deliver a few inches from late Friday night through Saturday night.

Also, I'm still liking the potential for a WINDEX event for much of the Upstate region during the day Saturday as the s/w swings through along with a pretty decent shot of DPVA. These events aren't always reflected in the model QPF fields (because they generally don't amount to much measurable)...but I can envision a few bands of graupel and/or snow dropping from NW-SE across the region, which could briefly whiten the grass in spots. The kind of situation where the sun is out, then it suddenly pours graupel for about five minutes followed by the return of the sun. Some may find that interesting, but as with summertime convection these events tend to be hit or miss.

[lakeeffectkid383]

ill take whatever snow we can get Justin

[heavy_wx]

The 06z nam shows a pretty impressive looking sounding for Jamestown, NY around Saturday morning, with the moist unstable layer extending up to around 675 mb. This results in about 700 J/kg of LICAPE and only some light shear. However, the 850 mb winds at 320 or so will shorten the fetch and make it a little more difficult to get a connection from the longest fetch of Lake Huron. The GFS doesn't extend the moist layer as high, only getting up to around 725 mb but still pretty favorable for lake effect.

For Lake Ontario, the nam soundings don't look quite as impressive with some dry air in the lowest 50-100 mb and a more shallow moist layer extending to around 725 mb Saturday evening.

[lakeeffectkid383]

The 06z nam shows a pretty impressive looking sounding for Jamestown, NY around Saturday morning, with the moist unstable layer extending up to around 675 mb. This results in about 700 J/kg of LICAPE and only some light shear. However, the 850 mb winds at 320 or so will shorten the fetch and make it a little more difficult to get a connection from the longest fetch of Lake Huron. The GFS doesn't extend the moist layer as high, only getting up to around 725 mb but still pretty favorable for lake effect.

For Lake Ontario, the nam soundings don't look quite as impressive with some dry air in the lowest 50-100 mb and a more shallow moist layer extending to around 725 mb Saturday evening.

You think we'll see our first LES advisories round here this season?

[Met1985]

Happy Thanksgiving Everyone! Hope everyone has a wonderful day!

[heavy_wx]

You think we'll see our first LES advisories round here this season?

Maybe for Chautauqua and Cattaraugus counties. I think the only areas that might see advisory level accumulations will be at high elevation and where a Huron connection occurs.

[kulaginman]

Happy Thanksgiving everyone! Thought I'd post a few images from the local 4km workstation ETA that is run out of the NWS in Burlington VT. This model is a pretty good tool when it comes to forecasting orographically-enhanced snowfall along the Green Mountain spine in Vermont; not sure if it is quite as useful when it comes to forecasting LES, but I guess we'll find out before the end of the weekend. In any event, check this out:

10PM Friday Evening:

Sometimes the models do have a tendency to place bands a bit farther south than what ultimately verifies during early season events on Lake Erie as they have been known to underestimate the feedback caused by relatively warm lake waters (a warm lake enhances convergence over the middle of the lake which causes more backing of the boundary layer winds downstream); I know this is something local meteorologist Don Paul has talked about in his blog, and there may be some documentation available online. As a result, there's a chance this band will end up developing closer to the Buffalo south towns for at least a short while tomorrow evening...but at that time, surface temperatures may still be marginal for accumulation. However with lake-induced CAPEs exceeding 700J, there may be a fair amount of graupel due to convective processes and graupel will accumulate at higher temperatures as opposed to snow. I don't really expect surface temperatures to drop near/below freezing in the lower elevations until around midnight.

4AM Saturday Morning:

Any organized lake band will probably be disrupted by this time as the s/w trough axis will have shifted to our east, and this is more of an upslope signature for the Chautauqua Ridge.

10AM Saturday Morning:

Check out that Georgian Bay streamer impacted the southern/western suburbs of ROC! Meanwhile, upslope continues along the Chautauqua Ridge.

1PM Saturday Afternoon:

The upslope signature actually increases south of BUF with organized snowfall re-developing as far north as the Boston Hills, likely due to better aligning of winds from a northwesterly direction combined with perhaps a slight increase in synoptic scale moisture and steepening of low to mid level lapse rates due to diurnal influences. We'll have to watch for Georgian Bay streamers edging into the northern/eastern suburbs of BUF too.

Overall I don't anticipate this being a particularly high impact event, but the weekend will certainly have a wintry look/feel for at least parts of Western NY. The immediate vicinity of BUF and its nearby suburbs may find itself in a bit of a screw zone, but areas farther south and northeast could do alright.

[WNash]

Thanks for putting that up. I'm particularly interested in seeing how that band NE of Buffalo verifies. We're in North Buffalo and I don't expect anything but an overcast sky and a cold NW wind.

[BuffaloWeather]

WOW! Kula that is amazing analysis. If you could do that for every Lake Effect System all year I will be ecstatic!!! =)

[kulaginman]

Haha I'll try to peek in and post my thoughts now and again, but it's tough since I no longer have hours upon hours to analyze the wx like I used to. Living in eastern MA, I tend to focus more on that part of the country as well (naturally)...but hopefully there are some decent LES events to track this year.

Regarding the Georgian Bay streamer; that is often hit or miss, and even the mesoscale models typically struggle to resolve such small scale features. I think all we can really say at this point is the signal is there for some localized streamers originating from the upper lakes; their location, longevity, and intensity is still very much in question at this point. Georgian Bay/Lake Huron streamers often come down to nowcasting, so we'll see how things are shaping up come Saturday.

[WNash]

I'll keep an eye on the possible Georgian Bay feature. I need to take a trip up to Lockport this weekend anyhow, so I'll see if there's anything I can observe and update you. I should say that I meant that I expect only clouds and wind HERE in the city-- no expectations about that Georgian Bay connection but that analysis you posted was really a treat.

[lakeeffectkid383]

Id be happy with an inch this weekend.

As always, nice analysis Justin.

[OSUmetstud]

Still some reasonable potential for the LES band to develop around BUF/BUF southtowns in the 00 to 03z time frame before shifting south. Depending on it's organization, it could deliver an inch or two...or at least get a nice burst as low-level temps remain warm in the post-frontal near dry adiabatic profile.

[lakeeffectkid383]

Still some reasonable potential for the LES band to develop around BUF/BUF southtowns in the 00 to 03z time frame before shifting south. Depending on it's organization, it could deliver an inch or two...or at least get a nice burst as low-level temps remain warm in the post-frontal near dry adiabatic profile.

Nick NWS mentions the chance for accumulating snow for the BUF metro as winds swing back to the SW Sunday morn -afternoon.

LAKE EFFECT ACTIVITY SHOULD BEGIN TO WANE LATE SATURDAY NIGHT AND

SUNDAY AS DRY AIR BEGINS TO ENTRAIN...AS UPSTREAM SURFACE RIDGING

STARTS TO BUILD INTO THE REGION. HOWEVER...A WEAKENING BAND OF LAKE

EFFECT SNOW SHOULD MAKES ITS WAY NORTHWARD INTO THE BUFFALO METRO

AREA BY LATER SUNDAY MORNING OR DURING THE AFTERNOON...AS THE LOW

LEVEL FLOW BACKS AROUND TO SOUTHWEST. THERE IS SOME POTENTIAL FOR

ACCUMULATING SNOWS...BUT THIS WILL DEPEND ON HOW FAST THE WEAKENING

TREND WILL BE.

[kulaginman]

Yes! The best chance for accumulating snows in the immediate vicinity of BUF will be during the day Sunday as boundary layer winds back to the SW but temps aloft remain marginally supportive of LES. I don't foresee the band remaining in place for long enough to deliver significant amounts...but places in and around the city and surrounding suburbs could see a quick inch or two if things break just right.

[lakeeffectkid383]

Yes! The best chance for accumulating snows in the immediate vicinity of BUF will be during the day Sunday as boundary layer winds back to the SW but temps aloft remain marginally supportive of LES. I don't foresee the band remaining in place for long enough to deliver significant amounts...but places in and around the city and surrounding suburbs could see a quick inch or two if things break just right.

what do you think for us here in OP over the course of the weekend Justin?

[OSUmetstud]

Yeah, I could see that on Sunday, too. WAA events can occasionally surprise. I was just focusing on tomorrow evening.

[kulaginman]

I think there is a possibility the lake band could initially set up very close to us around 21z tomorrow, but sometimes when temperatures are near or above freezing and there is a fair amount of lake induced instability the band doesn't have the "classic" look of a mid-winter lake band. In other words, it could be a disorganized area of convective "blobs" with bursts of heavy snow and graupel followed by periods of very light precip or no precip at all. This could continue through ~03z or a little after tomorrow evening as Nick mentioned above, but ultimately the band will settle south into ski country. I probably have a better shot at accumulation here on the hill than you do down in the village...but there could be a light coating mainly on the grass/cartops and other elevated surfaces. Temperatures will probably be a little too mild for much accumulation on the roads during the timeframe when the band will be over us, unless it comes down heavier than expected.

I don't really think we'll see much activity from later tomorrow evening through Saturday night. Things will transition into more of an upslope event at that time with most of the activity getting hung up along the Chautauqua Ridge...possibly extending north into the Boston Hills at times. We could even see some sunshine on Saturday, but it will be cold and windy with temperatures hovering near freezing.

As winds back to a more southwesterly direction and the fetch across Lake Erie increases Sunday morning, I think we could see a more organized lake band redevelop and lift into our vicinity in the 14-19z timeframe which is probably our best shot at a 1-2" accumulation. This is always a tough call as the inversion will be lowering, warm advection will be setting in, and the boundary layer winds will be steadily backing...but I feel pretty good that we'll at least see some accumulation during this timeframe.

[OSUmetstud]

Kulaginman, I know you were highlighting the backed winds a few days ago, and then backed off of it as the models dropped it. But there is a definite trend today of maintaining winds SW longer as the cold air moves in, instead of waiting for the wind shift to west to or west-northwest when the cold air arrives. It probably doesn't mean all that much, though.

If this -NAO had popped a few days earlier, this could have been a nice event as the system would have slowed down and occluded. Oh well.

[lakeeffectkid383]

Hope we cash in here with at least an inch on the grass.

[OSUmetstud]

Btw, the wind shift with the secondary trough will likely be too strong to just cause the band to shift gradually into the southern tier. I think it will "break off" the lake and shift SE, then upslope/multiband les will develop in it's wake.

[OSUmetstud]

Is randytracker checking his prospects for an LES field trip?

[lakeeffectkid383]

00z GFS keeps us as all snow here for the Tue-Wed system. Not much QPF, about 1/2" but its better than nothing.

[stormtracker]

Is randytracker checking his prospects for an LES field trip?

Ha, indeed. I'm itching to go on a chase, but this one looks like a lamer.

[OSUmetstud]

00z GFS keeps us as all snow here for the Tue-Wed system. Not much QPF, about 1/2" but its better than nothing.

That track is probably about the best we can hope for in terms of synoptic snows.

[OSUmetstud]

Ha, indeed. I'm itching to go on a chase, but this one looks like a lamer.

yeah, no sense of chasing this thing. Maybe we can get something later next week.

[lakeeffectkid383]

That track is probably about the best we can hope for in terms of synoptic snows.

would be awesome to verify. Nice little WWA prob 3-5" event with some nice winds and lake effect to follow.

[kulaginman]

Nick, I agree with you regarding the abrupt wind shift pushing the band off the axis of the lake tomorrow night. I almost wonder if there's a chance we could do better here in the south towns tomorrow evening than areas on the downslope side of the Chautauqua Ridge will do later tomorrow night into Saturday. As you mentioned, the SW/WSW flow could persist a bit longer than what the models had been advertising about a day ago...so the lake band could hover in my vicinity (near the Orchard Park/Boston line) for at least 3-4 hours tomorrow evening. I'm a little concerned we won't be able to cool the surface quickly enough for much accumulation though.

It's a mild night here at 1200' by the way! Temp still holding at 52F here while I'm noticing it's down to 30F back home in Norwood MA with the 10th consecutive night of frost.

[lakeeffectkid383]

Nick, I agree with you regarding the abrupt wind shift pushing the band off the axis of the lake tomorrow night. I almost wonder if there's a chance we could do better here in the south towns tomorrow evening than areas on the downslope side of the Chautauqua Ridge will do later tomorrow night into Saturday. As you mentioned, the SW/WSW flow could persist a bit longer than what the models had been advertising about a day ago...so the lake band could hover in my vicinity (near the Orchard Park/Boston line) for at least 3-4 hours tomorrow evening. I'm a little concerned we won't be able to cool the surface quickly enough for much accumulation though.

It's a mild night here at 1200' by the way! Temp still holding at 52F here while I'm noticing it's down to 30F back home in Norwood MA with the 10th consecutive night of frost.

hope your right Justin. Were about 3.5 mi apart as the crow flies but you have 300 feet of elevation on me which definitly increases your chances over mine of seeing accumulating snows tomorrow night. It'll be nice to just see flakes in the air and some lake effect on radar.