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Combined OBS-Nowcast for a snow to rain event , mainly interior only, Saturday morning Feb 27


wdrag
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Friday 525PM: Made this a combined obs-nowcast minor event thread. 509PM:  Possibly my last update for the evening. Other than the low levels being a little too warm, it's conceivable that snow will be seen to within about 10 miles of the NJT late tonight with minor (trace to 2") accumulations as previously discussed ne PA/nw NJ/se NYS and I84 northward in CT.  No new obs thread for this for many reasons, including minor 1-4 hour wintry event, occurring during the night when many will be sleeping and many areas melting as it hits the ground.  
 
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Friday morning 625 AM update:  1201AM-10AM Saturday (27th). Not anticipating an obs thread since the percentage of members involved (seeing snow/sleet) looks to be rather small. Just tag it on here, whatever might occur.   A 1-4 hour period of showery wet snow-sleet will probably occur across the I-84 corridor early Saturday inclusive of nw NJ, ne PA northeastward.  There even could be spotty freezing rain? Minor-short duration impact, at worst, reserved primarily higher terrain where an inch or 2 is possible in the Poconos. Elsewhere for the I84 corridor, inclusive of nw NJ, expect a Trace-3/4";  A quick change to rain occurs shortly after onset, except that change to rain in the Poconos and northwest hills of CT may not occur til ~ 10AM Saturday. Melting all surfaces once the change to rain has occurred. Most may not notice the snow if sleeping.
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730A/Thursday the 25th: As a friend said yesterday, winter's back is broken.  3AM - 10AM Saturday (27th), a 1-4 hour period of wet snow will probably occur across the I-84 corridor west of Hartford early Saturday. Possible minor short duration impact at worst, reserved primarily higher terrain where an inch or 2 is possible before a change to rain around or after 10AM Saturday and then melting all surfaces. Most may not notice the snow if sleeping.  No obs thread, unless modeling shifts a little closer to NYC (within 10 miles).

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Wednesday morning Feb 24 640A update: Updated title to only Saturday morning the 27th, and mainly interior only. Have posted nw suburbs thread since this nuisance negligible event appears focused for only high terrain of an inch or so Saturday morning before a change to rain/melting. Might provide a bit of a minor slippery slushy hazard untreated surfaces before sunrise Saturday nw of I287, i.e. nw NJ hills/ne PA Poconos and interior se NYS toward the Catskills, and possibly Litchfield County, northern Fairfield County CT.

Small possibility of an obs thread if snow occurs as some modeling tries to do to within 10 miles of NYC, but for now... not counting on that thread. This one would suffice, if this does minor snow occurs. Probably good to monitor NAM/RGEM cycles for consistent trends-if any. And the GFSv16 too, if you have access thru Pivatol Weather. V16 may be available elsewhere? If so, please share. COD?

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543A/23 -Tuesday. Incorporated 00z/23 ensembles and modeling through 06z/23... suggests maintaining some vigilance for a period of Saturday morning snow, probably Trace- as much 4" for the I84 corridor Saturday morning. Multiple modeling has that option. LI/NYC probably rain but may briefly start as wet snow? WPC is trying to keep us dry but i don't think that will work. My concern for a minor snow event are how close to NYC (mainly w of 287?) or possibly a little closer.  There will have been a freshening of the cold prior to this pulse of WAA which will be reflected with a small mid Atlantic coastal low.  Want to wait this out til the morning of the 24th to be more definitive. Modeling is all over the place and thermal profiles marginal, as so many. No ensemble prob graphic since WPC has little or no qpf (less than 0.10").

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628A/22: Despite some dry forecasts, my confidence in another snow event is categorical interior and likely coasts inclusive of LI.  Have changed the title to Noon Friday (and extended from 6A Sat to Noon Saturday) and simplified the wording. Most of this should be Friday night-Saturday morning. I expect this to be a hazardous event on all untreated surfaces by sunrise Saturday (interior).  Am even a little uneasy on the previous low chance >.25" in the title. For now , I see a 1 to possibly 6" snow event for the forum with highest totals, whatever they are,  in the interior high terrain-probably ne PA/extreme nw NJ/se NYS Orange County northward.  00z/22 EC changes to rain everywhere, whereas the GFSV16 is further south and ends briefly as rain midday Saturday.  Nice competition between the EC/V6 op runs.  GGEM sides with the EC though seems slightly colder than the EC. My initial 20th post concerns for Thursday the 25th, seems to have evaporated due to dominance of high pressure arriving behind the southward proceeding cold front.   

One other note i should add: NAEFS says EC probably has a better handle than the colder model solutions. I'm not buying the NAEFS warmth for the interior, at least not at this time. This will be  a big test of the GFSv16, soon to be implemented as a replacement for the GFS op (V15).

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627A/21:  WPC continues dry but as you probably saw, the 06z/21 GFS V15-16 have turned northeast.  This is a complicated situation with other snow/ice options. First, it's not clear to me that something cant happen here late Thursday-Friday (25-26). The Saturday morning (27 option) may force me to adjust the window of opportunity into the 27th. That part is associated with a subtle trailing shortwave moving ENE from the Ohio Valley (WAA) behind the initial primary short wave passage of the 26th.  That subtle short wave induces low pressure newd to the Mid Atlantic coast with a possible inverted trough back to the Catskills. What's it mean for NYC?  Possibly a period of snow or sleet? with a better chance of snow or sleet inside of I95.  Does it change to rain in the interior if it does come  north- too early to know. First, I think we need this option to stick, so to speak, and then can venture to discuss this minor or moderate event? Lets give this 24 hour more of cycles and then try to isolate the wintry problem, if it still exists Monday morning, 

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301P/20:  While 12z/20 GEFS guidance was delayed for full review (and therefore NAEFS), there is potential for a light or even moderate fast moving (east or east northeast) precip event. Depends in part whether the primary low crosses the St Lawrence Valley, or whether the front sags south of the forum with a wave of low pressure scooting eastward on it, as a fairly strong wave heads east from the Great Lakes.  Ensembles at this writing are not favorable for much of an event but individual models for the past 2 days have proposed an advisory snow either in our forum, or south of us,  across the Virginias/Delmarva.  The latest 18z/20 WPC guidance basically has no qpf in our forum for this event, so it could easily be a bust. I think some wintry precip will happen here, but could be 100% wrong. Let's leave the door open for a couple of days and see if this can target a portion of our area with an inch or more of snow. If snow does occur but only I84 corridor, then there won't be an obs thread (fewer members). TBD. .

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Also, this one may be trending the right direction. V16 now has 3"+ much of the area just north of I80 the morning of the 27th.  So far , continues ever more interesting.  Looking at a big big winter here...certainly FEB has a good chance top 5 or better now by Friday night in CP. One event at a time.  

 

Suggest continuing clearing gutters SAFELY!!!! I-84 corridor to near NYC. Roof leaks developing.  Subtle but significant in ne PA. Could  be happening elsewhere, Just not news compared to everything else going on. 

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Imperfect but something will come of this. Maybe its snow to rain but it is a pattern that has been finding ways to snow.  That will eventually end but not til at least March 2 (next 3 threaded events omitting the negligible showery rain/snow event early Tuesday afternoon).

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1 hour ago, wdrag said:

Imperfect but something will come of this. Maybe its snow to rain but it is a pattern that has been finding ways to snow.  That will eventually end but not til at least March 2 (next 3 threaded events omitting the negligible showery rain/snow event early Tuesday afternoon).

Walt 3-5 in snow event for the LV. WWA issued for the snow event on Monday here. Model amounts have ticking up the last few days. Lots of convection- expect to see pancake size flakes for a few hours. The storm next week has me concerned- a few more ticks east and another significant winter event in the making.

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1 hour ago, Albedoman said:

Walt 3-5 in snow event for the LV. WWA issued for the snow event on Monday here. Model amounts have ticking up the last few days. Lots of convection- expect to see pancake size flakes for a few hours. The storm next week has me concerned- a few more ticks east and another significant winter event in the making.

Agreed...you called it a couple days ago. I tend to be more conservative on urban...  short term attempt at targeting. some have it south of you, others north of you. Yes on the next two gtrheaded events beyond., Right now the V16 has nothing for 28--early 2  but don't think that will last against ensembled increasingly heavy qpf of snow to rain ending as snow.  Keeps the interest going.

 

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628A/22: Despite some dry forecasts, my confidence in another snow event is categorical interior and likely coasts inclusive of LI.  Have changed the title to Noon Friday (and extended from 6A Sat to Noon Saturday) and simplified the wording. Most of this should be Friday night-Saturday morning. I expect this to be a hazardous event on all untreated surfaces by sunrise Saturday (interior).  Am even a little uneasy on the previous low chance >.25" in the title. For now , I see a 1 to possibly 6" snow event for the forum with highest totals, whatever they are,  in the interior high terrain-probably ne PA/extreme nw NJ/se NYS Orange County northward.  00z/22 EC changes to rain everywhere, whereas the GFSV16 is further south and ends briefly as rain midday Saturday.  Nice competition between the EC/V6 op runs.  GGEM sides with the EC though seems slightly colder than the EC. My initial 20th post concerns for Thursday the 25th, seems to have evaporated due to dominance of high pressure arriving behind the southward proceeding cold front.  No graphic since WPC's 04z/22 issuance based on older ensembles/op cycles have no precip. 

One other note i should add: NAEFS says EC probably has a better handle than the colder model solutions. I'm not buying the NAEFS warmth for the interior, at least not at this time. This will be  a big test of the GFSv16, soon to be implemented as a replacement for the GFS op (V15).

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Doesn't look as promising via 12z/22 modeling but also think modeling is a bit muddled. I still am surprised that high pressure comes in so strong on the 25th.  500MB ensemble field to me suggests it's waiting for a short wave passage on the 26th.  Anyway,  can't outdo the modeling...just am not understanding it very well. 

Trend is to a  minor event on the 27th and negligible but I need to wait this out another day or so. Will reevaluate Tuesday morning. Jus too early to circular file this thread. 

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543A/23 -Tuesday. Incorporated 00z/23 ensembles and modeling through 06z/23... suggests maintaining some vigilance for a period of Saturday morning snow, probably Trace- as much 4" for the I84 corridor Saturday morning. Multiple modeling has that option. LI/NYC probably rain but may briefly start as wet snow? WPC is trying to keep us dry but i don't think that will work. My concern for a minor snow event are how close to NYC (mainly w of 287?) or possibly a little closer.  There will have been a freshening of the cold prior to this pulse of WAA which will be reflected with a small mid Atlantic coastal low.  Want to wait this out til the morning of the 24th to be more definitive. Modeling is all over the place and thermal profiles marginal, as so many. No ensemble prob graphic since WPC has little or no qpf (less than 0.10").

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Good Wednesday morning Feb 24,  Have posted nw suburbs thread since this nuisance negligible event appears focused for only high terrain of an inch or so Saturday morning before a change to rain/melting. Might provide a bit of a minor slippery slushy hazard untreated surfaces before sunrise Saturday nw of I287, i.e. nw NJ hills/ne PA Poconos and interior se NYS toward the Catskills, and possibly Litchfield County, northern Fairfield County CT.

Small possibility of an obs thread if snow occurs as some modeling tries to do to within 10 miles of NYC, but for now... not counting on that thread. This one would suffice, if this does minor snow occurs. Probably good to monitor NAM/RGEM cycles for consistent trends-if any. And the GFSv16 too, if you have access thru Pivatol Weather. V16 may be available elsewhere? If so, please share. COD?

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730A/Thursday the 25th:  3AM - 10AM Saturday (27th), a 1-4 hour period of wet snow will probably occur across the I-84 corridor west of Hartford early Saturday. Possible minor short duration impact at worst, reserved primarily higher terrain where an inch or 2 is possible before a change to rain around or after 10AM Saturday and then melting all surfaces. Most may not notice the snow if sleeping.  No obs thread, unless modeling shifts a little closer to NYC (within 10 miles).

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Friday morning 625 AM update:  1201AM-10AM Saturday (27th). Not anticipating an obs thread since the percentage of members involved (seeing snow/sleet) looks to be rather small. Just tag it on here, whatever might occur.   A 1-4 hour period of showery wet snow-sleet will probably occur across the I-84 corridor early Saturday inclusive of nw NJ, ne PA northeastward.  There even could be spotty freezing rain? Minor-short duration impact, at worst, reserved primarily higher terrain where an inch or 2 is possible in the Poconos. Elsewhere for the I84 corridor, inclusive of nw NJ, expect a Trace-3/4";  A quick change to rain occurs shortly after onset, except that change to rain in the Poconos and northwest hills of CT may not occur til ~ 10AM Saturday. Melting all surfaces once the change to rain has occurred. Most may not notice the snow if sleeping.

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509PM:  Possibly my last update for the evening. Other than the low levels being a little too warm, it's conceivable that snow will be seen to within about 10 miles of the NJT late tonight with minor (trace to 2") accumulations as previously discussed ne PA/nw NJ/se NYS and I84 northward in CT.  No new obs thread for this for many reasons, including minor 1-4 hour wintry event, occurring during the night when many will be sleeping and many areas melting as it hits the ground.  

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Just now, gravitylover said:

...and here comes the fog with rain :( Now it's a race against the clock to see if the snowpack can hold out until tomorrow night to give me a wall to wall month with no grass showing, the only bare spot on my property is on the south side of one of my big trees.

Not sure about wall-wall but I think you'll keep your fair percentage of your snowpack.  The best chance of a big warmup is early Monday afternoon.  Otherwise, lack of wind will keep air temp down, plus cloud cover, and so the rain will absorb and ripen the pack a bit. Fog may be the biggest pack eater, especially Sunday night.   I'm not even sure the snow that fell this morning will melt on its own here and I'll clear it during midday, Takes heat out of the air to melt/evap.  Helps w keeping temps a bit cooler. Hope we all can keep most of what we have into the 4th.  Post us tomorrow and Monday on pack status. 

 

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