January 29-30, 2019 Arctic FROPA

[SomeguyfromTakomaPark]

Everything looks a little improved.  The gfs still looks really good.  2-5 inches for most of the corridor between dc and Baltimore. 

[showmethesnow]

Have seen a notable shift of the precip maxes westward, centered roughly on the cities (Balt/DC) on the 06Z GFS. Snowfall map has notably improved especially for those around the Balt area.

[DSF]

I would take that in a heartbeat, but somehow I don't see it working out that way. 

LWX has revised things downward in terms of impact for NE Baltimore several times since yesterday afternoon. 

[arlwx]

The latest from LWX:

.NEAR TERM /THROUGH TONIGHT/...

Cut back on snow totals and advisory area a bit based on 1) slight
downward trend in QPF with latest guidance (and upstream radar
presentation), and 2) most precip falling as snow will likely be
falling with temps at or just above freezing. This will still cause
slippery travel especially on untreated surfaces as temperatures
fall through this evening, but totals appear more likely to be in
the coating-2" range as opposed to 1-3"+.

The leading edge of a large/deep upper low diving into the Great
Lakes will absorb a small spoke of southern stream energy, taking on
a negative tilt as it crosses the Mid-Atlantic later today. This
combined with strong frontal forcing in the 850-700 hPa layer is
expected to result in a band of precipitation along an eastward
moving surface cold front. Temperatures aloft will be cooling
through the day and support snow, but boundary layer temperatures
will be marginal (especially near/south of US-50). A rain/snow mix
or even plain rain is expected to start, before a change to wet
snow. Given the dynamics in play and the strong front, there could
be a few moderate bursts of snow. Most of the snowfall is expected
to occur in a 2-3 hour window in any one area (except northern
Maryland where a bit longer period of snow is expected due to
somewhat cooler temperatures). Further west, a relative minimum in
precipitation is expected with less than an inch of snow forecast in
the I-81 corridor (less precip) and over central VA (warmer temps).
Over the Allegheny Highlands, an inch or two of snow is likely,
followed by a period of light freezing drizzle.

As the front pushes eastward tonight, conditions dry out rapidly.
Lows will dip into the teens, with single digits over the higher
elevations.

 

 

[showmethesnow]

Mesos are better able to pick up on the finer features such as lift (850-700mb) but for whatever it's worth we also saw an improvement on the 06Z GFS for thr DC/Balt region.

Have liked what I have seen with the American suite of the models this morning. Now does someone want to throw out the 06Z Euro and squash these good vibes? 

eta: Talking for the DC/Balt corridor North and west.

[North Balti Zen]

Those are nice positive last minute trends. Fingers crossed.

[CAPE]

FV3 continues to be the model to hug for most.

Consistently gives my yard 2-3". All other guidance is an inch or less.   

[SomeguyfromTakomaPark]

54 minutes ago, showmethesnow said:

Have seen a notable shift of the precip maxes westward, centered roughly on the cities (Balt/DC) on the 06Z GFS. Snowfall map has notably improved especially for those around the Balt area.

FV3 also looks great for the cities 

[CAPE]

The 6z 3km NAM develops an enhanced band of snow over the central/lower eastern shore. Verbatim it misses my house by a few miles. This winter, that will definitely verify lol.

[Ruin]

I dunno the snow on radar is just breaking up. another joke storm it seams to be.

[osfan24]

GFS and FV3, with decent ratios, is a borderline warning event for parts of the area. Weird to see GFS as most bullish model, especially when the old GFS is more bullish than the new one. My guess is 3K NAM has a better handle on things with around 2 inches along 95 and then 3-4 once you get into psu land.

[SomeguyfromTakomaPark]

1 minute ago, Ruin said:

I dunno the snow on radar is just breaking up. another joke storm it seams to be.

Can you save the weenie radar hallucinations for closer to the actual event.  It’s a little early. 

[Scraff]

4 minutes ago, Ruin said:

I dunno the snow on radar is just breaking up. another joke storm it seams to be.

You should probably cliff jump now and call it a day. 

[showmethesnow]

8 minutes ago, C.A.P.E. said:

The 6z 3km NAM develops an enhanced band of snow over the central/lower eastern shore. Verbatim it misses my house by a few miles. This winter, that will definitely verify lol.

Snow chase to your neighbors? 

Still haven't seen mention of the 06Z Euro. Not that I really want to hear from Dr NO mind you.

[MillvilleWx]

The 3km is showing a healthier expansion of the qpf further west due to the increased H7 frontogen along the Allegheny Front. Coupled with a solid jet streak placement over PA placing the area in the right entrance of the jet, this would provide the region with better lift, maxing both qpf and dendritic growth as the greatest omega will be positioned right within the DGZ (See pic below). This is all solid trends for west of the bay, but east of the bay might maintain a tongue of warmer air aloft, limiting the chances of seeing more prolific snowfall. However, as the trough axis swings overhead, a decent area of PVA will accompany the trough base, so a secondary burst of precip on the eastern shore is possible before exiting. Places like Parr's Ridge are obviously in the best spot due to the slightly colder temps locally and the added orographic enhancement as the front swings east. 

It'll be important to monitor the trends in guidance at 12z. Mesos SHOULD have a better handle on the setup closing in, so any step forward or backward could be pivotal to the final outcome. Have to like the trends this morning. 

[Danajames]

For those of us(me included) that seem to lose power every time there's high winds, I'm a little concerned when the front starts to move through in earnest tomorrow.  In some heavier snow squalls, winds could gust near 50 MPH and that often spells trouble.  And you sure as hell don't want to lose power with the kind of temperatures headed this way.  Hopefully, like last Monday, the lights will just flicker a few times.  Everybody be safe if you're going to be out on the roads this evening and tonight. 

[SomeguyfromTakomaPark]

2 minutes ago, showmethesnow said:

Snow chase to your neighbors? 

Still haven't seen mention of the 06Z Euro. Not that I really want to hear from Dr NO mind you.

It’s not out until around 6:45

[nj2va]

32/27. Right in line with LWX forecast. 

[showmethesnow]

Just now, losetoa6 said:

Yep ..been snowing lightly here as well

Still light but it is now coming down a little harder. Have a coating on surfaces and have shaved off 1/2 degree on temps.

[HighStakes]

Just now, showmethesnow said:

Still light but it is now coming down a little harder. Have a coating on surfaces and have shaved off 1/2 degree on temps.

Getting some light stuff here as well.

[PivotPoint]

I love how LWX trimmed down their totals. And the 1/10 chance max is 3” dc. Even though I think 3” is more than what we’ll receive I don’t understand why they pair down these maps when current guidance is trending more in favor than it did when they had more robust maps up.

Always seems backwards to me when they post revised maps that don’t fit the current trends.

[showmethesnow]

Just now, PivotPoint said:

I love how LWX trimmed down their totals. And the 1/10 chance max is 3” dc. Even though I think 3” is more than what we’ll receive I don’t understand why they put down these maps when current guidance is trending more in favor than it did when they had more robust maps up.

Always seems backwards to me when they post revised maps that don’t fit the current trends.

Really don't follow LWX except for what is posted but I have to wonder if their bulletin was posted in regards to the 00Z suite runs. 

[North Balti Zen]

24 minutes ago, Ruin said:

I dunno the snow on radar is just breaking up. another joke storm it seams to be.

Dear lord. This early stuff is not the snow that will be this event. The early snow was well modeled to be just where it is. 

[SomeguyfromTakomaPark]

@showmethesnow

No major changes 

[dailylurker]

Temp torching in my area. It's gone from 31 to 34 since 5:30am. Not expecting anything here except 60's all next week lol

[heavy_wx]

32 minutes ago, MillvilleWx said:

The 3km is showing a healthier expansion of the qpf further west due to the increased H7 frontogen along the Allegheny Front. Coupled with a solid jet streak placement over PA placing the area in the right entrance of the jet, this would provide the region with better lift, maxing both qpf and dendritic growth as the greatest omega will be positioned right within the DGZ (See pic below). This is all solid trends for west of the bay, but east of the bay might maintain a tongue of warmer air aloft, limiting the chances of seeing more prolific snowfall. However, as the trough axis swings overhead, a decent area of PVA will accompany the trough base, so a secondary burst of precip on the eastern shore is possible before exiting. Places like Parr's Ridge are obviously in the best spot due to the slightly colder temps locally and the added orographic enhancement as the front swings east. 

It'll be important to monitor the trends in guidance at 12z. Mesos SHOULD have a better handle on the setup closing in, so any step forward or backward could be pivotal to the final outcome. Have to like the trends this morning. 

Interesting thermodynamics with this event too. Both the 06z GFS and 3-km NAM have a region of convective instability and associated elevated lapse rates between 650-550 mb this afternoon (you can see the decreasing theta-e with height in that sounding near 600 mb).

[MN Transplant]

Ping.  Little bit of sleet right now.

[winterymix]

Dear Heavy and Millville:  long time winter weather luvr here, about 60 years worth.  Thank you very much for sharing your expertise.  My backyard is Reisterstown-Glyndon.  Am thinking 1" Catonsville and 5" Parrs Ridge and moi in between.  Mets:   please continue to post forecast soundings with interpretation.  

[MillvilleWx]

1 minute ago, heavy_wx said:

Interesting thermodynamics with this event too. Both the 06z GFS and 3-km NAM have a region of convective instability and associated elevated lapse rates between 650-550 mb this afternoon (you can see the decreasing theta-e with height in that sounding near 600 mb).

I was noticing that too. There is a pretty stout area of PVA moving through in the PM around that time, so I wonder if a rumble of thunder is not out of the question. With lift like that through the DGZ, there should be some charge build up. We shall see

[Scraff]

1 minute ago, MillvilleWx said:

I was noticing that too. There is a pretty stout area of PVA moving through in the PM around that time, so I wonder if a rumble of thunder is not out of the question. With lift like that through the DGZ, there should be some charge build up. We shall see

I’ve only had 1 cup of coffee. Not ready for this type of dirty talk. Lol. If I got one lightning flash and a deep rumble of thunder during a heavy snow burst...my bar would be surpassed immediately. Fingers crossed.