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MAG5035

Central PA - Jan/Feb 2019 Obs and Discussion

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5 hours ago, MAG5035 said:

Few comments on the overall pattern before we get too close to our upcoming weather issues on tap.

My concern going forward in the next couple weeks is the major -PNA (western US trough) that has established itself. We have a really nice -EPO ridge in the Pac established as well but it seems that the alignment wants to dump the core of the anomalous low heights and the primary trough into the western US. With the major -EPO ridge shooting up into AK, that keeps us from torching via a Pacific flow... so overall temps look to be seasonable to maybe slightly below. On the other side there's no good -NAO or downstream ridging to help buckle heights on our side of the country. That leaves us vulnerable to cutters from a storm track standpoint, which has become a theme this winter. Lack of -NAO has been a theme too although thats been for more like the last 5+ years. That could possibly change via the East Pac ridge into AK shifting east towards the west coast in time or with establishment of + heights downstream in the NAO realm.

I would imagine MJO activity is driving the Pac pattern alignment, we've been mired in the P6-7 border region with the index making a backtrack towards 6 the last several days. It is forecast to get towards 8 but this backtrack has been pushing that prospect back in time. I think we will see the 8-1-2-3 run we're looking for from that teleconnection. But we might not get there till late in the month.  We'll be vulnerable to cutting storms in the meantime. 

diagram_40days_forecast_GEFS_member.gif.7bea64575c8cb741a02d24c225e9a9a7.gif4indices-1.thumb.png.4a776eb3de47881d692a91936f99a808.png

That's the most negative i've ever seen this site have the PNA.

The MJO progresses into phase 8 & 1 more quickly on the Euro MJO forecast today. 

The SOI also should be crashing over the next few days.

The models should respond with moving the trough more to the east by next week. Then the tour through MJO phase 8-1-2 should carry us to a great last month or so of winter !

B135E034-828F-4D1A-9058-65E98CC5C8F4.gif

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1 minute ago, lte5000 said:

sZtp6cb.png

You beat me to the punch.  0Z Nam drastic improvement in the snow department.  Mainly with the Monday night into Tuesday event.  It was saying around 2" of snow tomorrow night with less than 0.5" for Monday night.  Now this run gives 3" tomorrow night and 4" Monday night.  WOW!  I'll bet 3K doesn't look like this when it's out.

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Well, I'm sort of wrong about the 3K.  It also is much better than its prior runs.  It now gives us a total through 7AM Tues of 4.5" at MDT.  A quick look at the temps (at MDT at 12Z Tues, using the 3K data) has a surface temp of -1, 850 @ -3.  The zero line at 850 is just crossing the M/D line.  It also shows that somewhere between the surface and 500mb there is a temp of +2C which is the warmest temp in the column, but it's not at the surface, or 850, or 700.  It must be between the surface and 850.  I'll assume it's around 925mb.  That would tell me that it likely would still be snowing (rimed?) since I don't think you could melt snow completely at 925 and refreeze it to sleet in a distance of 3000 feet, or could you?  The chart shows no freezing rain accumulating through 12Z Tues, which is the current end of its run.

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12 minutes ago, CarlislePaWx said:

Well, I'm sort of wrong about the 3K.  It also is much better than its prior runs.  It now gives us a total through 7AM Tues of 4.5" at MDT.  A quick look at the temps (at MDT at 12Z Tues, using the 3K data) has a surface temp of -1, 850 @ -3.  The zero line at 850 is just crossing the M/D line.  It also shows that somewhere between the surface and 500mb there is a temp of +2C which is the warmest temp in the column, but it's not at the surface, or 850, or 700.  It must be between the surface and 850.  I'll assume it's around 925mb.  That would tell me that it likely would still be snowing (rimed?) since I don't think you could melt snow completely at 925 and refreeze it to sleet in a distance of 3000 feet, or could you?  The chart shows no freezing rain accumulating through 12Z Tues, which is the current end of its run.

I agree. Kinda a WAA situation right? If it’s been cold we can do well with these setups, it’s the other way around we typically fail (warm to cold).

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1 minute ago, canderson said:

I agree. Kinda a WAA situation right? If it’s been cold we can do well with these setups, it’s the other way around we typically fail (warm to cold).

I'd love to give a definitive answer but I don't know for sure.  Maybe MAG can answer when reads this.  Sounds reasonable to me, though.

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Quick update for MDT from Fv3:  only 0.3" tomorrow night, then 4.5" Monday night.  Will be interesting to see whether the GFS's or the NAM's win the snow war for tomorrow night's snow.  pretty significant difference with about 0.5" from GFS but nearly 3" from NAM by 12Z Monday.

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36 minutes ago, CarlislePaWx said:

Quick update for MDT from Fv3:  only 0.3" tomorrow night, then 4.5" Monday night.  Will be interesting to see whether the GFS's or the NAM's win the snow war for tomorrow night's snow.  pretty significant difference with about 0.5" from GFS but nearly 3" from NAM by 12Z Monday.

Here is the 0z Euro 10-1 ratio & Kuchera. This is the total snow amount through Wednesday am. 

About 2 inches of this is from round one tomorrow evening through Monday am.

The second & more significant round of snow starts back up by early Monday evening. It continues as snow in the LSV until Tuesday morning after sunrise. Then it mixes over to a long period of sleet & freezing rain that lasts until late Tuesday afternoon. Then it looks like most of us go to plain rain by Tuesday evening.

Most of the models are now showing not to be much of a break between round 1 & 2 on Monday afternoon.

It is another very good Euro run for CTP!

4718D99B-B4A3-42EE-9B95-A75FE20CCA02.png

4F24824A-F672-48EA-BB52-FB59CABE6464.png

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5 hours ago, canderson said:

I agree. Kinda a WAA situation right? If it’s been cold we can do well with these setups, it’s the other way around we typically fail (warm to cold).

Yea, ultimately it's a WAA situation overall with the parent low running west of us. The CAD setup though with the high pressure to the north is looking very stout. The alignment would bleed in cold air efficiently not only at the surface, but even at the 925 and 850mb levels. So I think the front end snow aspect of this system has a chance to do well before mixing. If you look at the height maps at those levels you even see the high pressure center in place there as well. It's pretty impressive IMO, it looks like the best setup of the winter thus far for such things. The 1040ish high is progged to be in a good spot and is not being easily or quickly moved off. Aside from the front end snow potential, this has me pretty concerned about ice storm impacts. My hope is the cold air stays deep enough to allow for more sleet over freezing rain.

Here's the morning 6z NAM freezing rain QPF. That's some pretty significant stuff, with >0.25" for most of the Sus Valley and major icing in the Laurels and central counties. The Euro has been very cold at 925mb and the surface too. Some areas of interior central don't really ever go above freezing at all on those models. The GFS still eventually routs out the cold and changes all to rain for a pretty decent period. I don't really buy much plain liquid at the moment with this setup. I anticipate CTP needing to open up with winter storm watches over most of not all the CWA (separate from the early snowfall this evening (Sun Night) for the multiple impacts and prospect of decent snow up front. 

nam-null--usne-84-C-zrtot_whitecounty.thumb.png.4de9f1f82c6b21f5b267f85610e9acc1.png

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Driving down route 70 to BWI this morning and all roads are Pre-treated and powdery white including 195 the feeder road to the airport.  That is always a good sign for the LSV if those southern boys think a cutter is going to give them road issues way down here.  Of course they have to worry about tonight's snow as well.

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First call.  Not going to search for my name list so just drawing some random names from memory

 

First event- area wide 1 to 2 inches possibly ending as some rain in the lsv.

 

Second event-

 

Mag, wmsptwx-3 to 6" with significant icing

Voyager, carlisle, canderson-2 to 4" with significant icing

Cashtown, dax, nut-2 to 4" with moderate icing 

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29 minutes ago, bubbler86 said:

Driving down route 70 to BWI this morning and all roads are Pre-treated and powdery white including 195 the feeder road to the airport.  That is always a good sign for the LSV if those southern boys think a cutter is going to give them road issues way down here.  Of course they have to worry about tonight's snow as well.

I don't know if it's a money issue or what, but up here in Schuylkill County, Penndot stopped spraying the roads about 10 years ago. In Allentown city, on the other hand, they spray EVERYTHING. Main roads, side streets, back alleys, you name it. I was surprised when I saw it.

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11 minutes ago, Voyager said:

I don't know if it's a money issue or what, but up here in Schuylkill County, Penndot stopped spraying the roads about 10 years ago. In Allentown city, on the other hand, they spray EVERYTHING. Main roads, side streets, back alleys, you name it. I was surprised when I saw it.

It certainly makes my tires and cars white even when dry.  Car washes are living the high life right now.

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17 minutes ago, bubbler86 said:

First call.  Not going to search for my name list so just drawing some random names from memory

 

First event- area wide 1 to 2 inches possibly ending as some rain in the lsv.

 

Second event-

 

Mag, wmsptwx-3 to 6" with significant icing

Voyager, carlisle, canderson-2 to 4" with significant icing

Cashtown, dax, nut-2 to 4" with moderate icing 

The 3k NAM at 6z agrees with your call.

Here are the maps for just round 1 & then the combined map for rounds 1 & 2 .

Also, just joking here, I feel left out of your forecast ! ... I live right between @canderson& @CarlislePaWx In Marysville, which is about 5 miles north of Harrisburg.

C137BD54-A048-4C9D-A368-B8A0C2829C33.png

66AF65E7-31E1-4440-8365-63C6837702D0.png

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1 minute ago, Blizzard of 93 said:

The 3k NAM at 6z agrees with your call.

Here are the maps for just round 1 & then the combined map for rounds 1 & 2 .

Also, just joking here, I feel left out of your forecast ! ... I live right between @canderson& @CarlislePaWx In Marysville, which is about 5 miles north of Harrisburg.

C137BD54-A048-4C9D-A368-B8A0C2829C33.png

66AF65E7-31E1-4440-8365-63C6837702D0.png

I even promised myself to include you this time and then forgot.  I know where Marysville is. 

Second event- Bliz. 2-4" with significant icing.  Lollipops of the up to 6" near your house:-).

 

Another LSV predict.

 

Monday- Schools on two hour delay, modified morning kinder.

Tuesday- Schools closed

Wednesday- Schools on two hour delay, modified morning kinder.

 

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6 minutes ago, pawatch said:

For you Icon guys...this was posted by Cranky the weather guy.

Other map is ice forecast for the storm.

image.jpg

image.jpg

You are risking a permaban! Lol.

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5 minutes ago, bubbler86 said:

I even promised myself to include you this time and then forgot.  I know where Marysville is. 

Second event- Bliz. 2-4" with significant icing.  Lollipops of the up to 6" near your house:-).

 

Another LSV predict.

 

Monday- Schools on two hour delay, modified morning kinder.

Tuesday- Schools closed

Wednesday- Schools on two hour delay, modified morning kinder.

 

Look at you today throwing out predications :scooter:

I agree with you too...

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12z nam looking a little less w/ round 1 down here, but round 2 is looking good so far.  Focusing south of MD line as their success becomes our success w/ this storm.  Every hour the cold can hold, is my focus.  Anything frozen is a win in this challenging winter.

looks like central md is the real battle zone.  Going to watch that line in the next couple runs.  That will be a reflection of thermal battlezone.  CAD typically is undermodeled, so lets hope today is catch up day.  

 

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14 minutes ago, pasnownut said:

12z nam looking a little less w/ round 1 down here, but round 2 is looking good so far.  Focusing south of MD line as their success becomes our success w/ this storm.  Every hour the cold can hold, is my focus.  Anything frozen is a win in this challenging winter.

looks like central md is the real battle zone.  Going to watch that line in the next couple runs.  That will be a reflection of thermal battlezone.  CAD typically is undermodeled, so lets hope today is catch up day.  

 

Yea, verbatim the 12z Nam is really close to this busting badly (as it pertains to snow specifically) for South PA.  Funny how models seem to know where the mason dixon.  So often I see cut offs right on the line.  Need cad at all levels to keep it flakes.

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16 minutes ago, bubbler86 said:

Yea, verbatim the 12z Nam is really close to this busting badly (as it pertains to snow specifically) for South PA.  Funny how models seem to know where the mason dixon.  So often I see cut offs right on the line.  Need cad at all levels to keep it flakes.

If even even half of this is a bust, then I think many of us will take it !

 

DA285E9F-1149-4B23-8DFC-6E2861366864.png

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Just now, Blizzard of 93 said:

If even even half of this is a bust, then I think many of us will take it !

 

DA285E9F-1149-4B23-8DFC-6E2861366864.png

That includes sleet and ice.  Snowfall maps were a bit less.

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8 minutes ago, Blizzard of 93 said:

If even even half of this is a bust, then I think many of us will take it !

 

DA285E9F-1149-4B23-8DFC-6E2861366864.png

Yeah, the NAM has bad snowmap outputs as it is a snow or no output, so it is misleading, but has been known for many years, and a bias that I assume most weenies know by now. 

It still is useful for the thrmal fields MSLP etc.

BTW from my quick view, surface and 850's were a tick better this run.  Icon also ticking oolder at lower levels.

We know were' gonna rain, but like i said previously, every hour less is what Im rooting for.

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Here’s the latest weather works forecast for anyone interested. They’re calling for less than some of the local stations but they have had to play catch up in the past with similar setup storm systems. Wouldn’t be surprised if they change the totals for the main event tomorrow evening a little bit. Right now they’re calling for a 1-2” event tonight and 2-4” tomorrow with up to a tenth inch of ice. Either way it makes our job messy and more difficult when it’s not all snow falling. 

Sno-Services (Harrisburg).pdf

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Honestly to my amateur eyes I don’t see zr being a significant issue for anyone outside the Laurels. ZR here is kinda hard to come by with entrenched cold - it rarely comes to fruition. 

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Why don't we have winter storm watches out yet for Monday night/ Tuesday?  The expected combination of snowfall and ice accretion should easily meet WSW criteria.  Unless they are going with a watch in the afternoon package and then an upgrade to warning tomorrow morning?

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