February 16-17, 2024 | NE / Mid-Atlantic Winter Storm

[Undertakerson2.0]

[Undertakerson2.0]

[Undertakerson2.0]

look at how 850 juiced up now that the system is tapping both H7 fields. Strongest is N of course, but it is drawing in some of the Gulf pwat - just the edge mind you. Still...

 

 

[Undertakerson2.0]

It's a cranking for a tiny wave. The convection will NOT come up here imho - it will lose diurnal heating and dissipate SW of us as we move on. 

 

Edited February 16 by Undertakerson2.0

[Rickrd]

Yup. Just upped the Lehigh Valley to 2-4 locally 5”. We shall see. SNOW ON SNOW BABY!!!

[MDBlueridge]

Whoa who got a hold of Sterling?! Very nice write up! 

As of early afternoon, a pair of mid/upper-level shortwaves
were digging into the Midwest/Ohio River Valley. At the
surface, a front remained stalled near the North/South Carolina
border, extending west to western Tennessee where a surface low
was continuing to develop. Satellite had what loosely resembled
a baroclinic leaf persisting over the lower Ohio River Valley
north of the surface low. Some lightning was being detected over
the middle Mississippi River Valley, indicating elevated
instability and strong, deep lift via low-level frontogenesis
and very strong upper-level divergence in the left exit region
of an incoming jet streak.

Trends will be closely monitored through the evening upstream,
as this system will be moving quickly eastward through tonight,
bringing snow to the Mid-Atlantic.

Clouds will increase through the evening as the system
approaches from the west. Snow will reach the Appalachian crest
early this evening. The snow will spread rapidly eastward
through the evening hours, becoming heavy at times due to the
strong forcing.

Aloft, there will be strong PVA as well as upper-level
divergence via the left exit region of a 180-200 knot jet. In
the low/mid-levels, intense WAA and isentropic lift/fgen is
anticipated north of the surface low. This intense, deep lift
stretches through the DGZ which will be deepening especially
north of US-50/I-66 tonight. For this reason, believe snowfall
rates may reach 1-2 inches per hour as heavier bands develop.
Although the steadiest snow will likely only last 3-4 hours in
any one spot, areas that are under heavier bands for most of
this time could see 5-8 inches given the higher rates, and that
is reflected in the high end (90th percentile) graphics. Areas
with stronger orographic lift (the northern Virginia Blue Ridge
and the Allegheny/Potomac Highlands and Catoctins) could even
see a little more enhancement on top of that.

The areas that are most likely to see warning-level accumulation
appear to be our climo-favored areas near and northwest of US-29.
This is where the DGZ looks deeper and the surface temperatures
will be a few degrees colder, reducing or eliminating any brief
initial melting of snow. This area is also favorably placed
100-150 miles north/west of the surface low track and just north
of the H85 low track, with a favorable overlap of upper
divergence/low-level fgen. It should be noted that some
guidance and upstream trends show the potential for multiple
bands of heavy snow, one perhaps more jet induced by upper-level
forcing (higher ratios/deeper DGZ, but less QPF), with another
driven more by low-level fgen (somewhat lower ratios but higher
QPF). Between these bands, there may be a bit of subsidence and
relative minima in QPF/snow. Confidence is a bit lower because
of this, but has increased enough to expand the Winter Storm
Warning given upstream trends and a general upward trend in QPF.
Further south/east across the central Virginia Piedmont, central
Shenandoah Valley (lower elevations), and southern Maryland,
surface temperatures will be a touch warmer; some melting and/or
mix with rain may cut down accumulations here, and a tight
gradient between lower vs. higher totals is likely from south to
north as a result.

[Undertakerson2.0]

AFDILN (RobB's WFO) Dayton Ohio

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Expanded the winter weather advisory to include Mercer,
Auglaize, Shelby, Logan, Union, and Delaware counties in Ohio.
Will revisit whether Mercer and Auglaize will need to be added
as the mid day hours progress. Already seeing banding of snow
develop. Went a little closer to the hi res models than some of
the other operational models which have the heaviest snowfall
totals a little further south due to them handling current
placement of snowfall a little better. In general have at least
1 to 3 inches across the region with a band of 2 to 4 and
locally higher amounts between 4 and 5 inches possible. Still
seeing the nice signal on the models for the fgen banding and
just trying to narrow down where the highest values with the
banding will be.

Edited February 16 by Undertakerson2.0

[TLChip]

10 minutes ago, clm said:

I thought PA used cinder.

They’ll spray brine if it’s dry before a storm, rock salt during. At least in my areas. 

[tcari394]

14 minutes ago, clm said:

I thought PA used cinder.

Cinder on the back roads/dirt roads.. salt on the mains.

[Pghsnow]

4-6 for me but no WSW. Just advisory.

[Anthonyweather]

3 minutes ago, Rickrd said:

Yup. Just upped the Lehigh Valley to 2-4 locally 5”. We shall see. SNOW ON SNOW BABY!!!

Ya I like 4-6 for most of us

[Anthonyweather]

2 minutes ago, tcari394 said:

Cinder on the back roads/dirt roads.. salt on the mains.

Cinders don’t melt snow. Then you have hard pack. 

[Lazman]

20 minutes ago, Wtkidz said:

3:00 surface.

 

Is that High over Delmarva the reason why models are going north? 

[Undertakerson2.0]

1 minute ago, Pghsnow said:

4-6 for me but no WSW. Just advisory.

"Just advisory" is simply another way of saying you're just shy of criteria for Warnings in your area. 

 

1 minute ago, Anthonyweather said:

Ya I like 4-6 for most of us

 

[Undertakerson2.0]

Just now, Lazman said:

Is that High over Delmarva the reason why models are going north? 

No - those maps are goofy AF. There is no High over Delmarva just like yesterday there was no "Low" in Texas at that time. 

In fact, we see pressure falls and even a tiny reflection of SLP at OBX 

 

[Undertakerson2.0]

fwiw, I think the Baby G finally caught on a bit more. 

Edit - meh, still OTL that one. 

Edited February 16 by Undertakerson2.0

[Lazman]

8 minutes ago, Undertakerson2.0 said:

No - those maps are goofy AF. There is no High over Delmarva just like yesterday there was no "Low" in Texas at that time. 

In fact, we see pressure falls and even a tiny reflection of SLP at OBX 

 

But, but, but......

[Pghsnow]

9 minutes ago, Undertakerson2.0 said:

"Just advisory" is simply another way of saying you're just shy of criteria for Warnings in your area. 

 

 

 

4-6 has always been a WSW not advisory here in Pgh area.  That snow will fall in a short timeframe and the forecast is saying heavy snow. Not that it matters, but it doesn't make sense when I see all these other areas with WSW for similar amounts.

[Undertakerson2.0]

3 minutes ago, Pghsnow said:

4-6 has always been a WSW not advisory here in Pgh area.  That snow will fall in a short timeframe and the forecast is saying heavy snow. Not that it matters, but it doesn't make sense when I see all these other areas with WSW for similar amounts.

This is from Pgh AFD and it expresses the criteria is 6, not 4-6 

Quote

With snow liquid ratios around 15-16:1 for this event, probability of exceeding warning criteria snow (6 inches) in our WV and PA ridges is around 80%.

https://forecast.weather.gov/product.php?site=NWS&issuedby=PBZ&product=AFD&format=CI&version=1&glossary=1&highlight=off

[Undertakerson2.0]

6 minutes ago, Lazman said:

But, but, but......

Not sure what to say about a product that will place an H where pressure is falling near 2sigma over 2 hours and has in fact a growing SLP at the bottom of the H. 

I

[Undertakerson2.0]

Mesoscale Discussion 0147
   NWS Storm Prediction Center Norman OK
   0304 PM CST Fri Feb 16 2024

   Areas affected...portions of southern Illinois into central and
   southern Indiana...southwestern Ohio...extreme northern Kentucky

   Concerning...Heavy snow 

  

Spoiler

Valid 162104Z - 170100Z SUMMARY...Heavy snow will continue over the next several hours. At least 1 inch/hour snowfall rates are expected, accompanied by periods of reduced visibility. DISCUSSION...Heavy snow has been on the increase in terms of coverage and intensity over the last few hours as surface cold air advection along/just north of the OH River is overspread by continued warm-air/moisture advection aloft. Within a broader zonal band of snow, the heaviest rates (i.e. 1+ inch/hr) should occur near the 700 mb frontogenesis axis, where ascent within the dendritic growth zone should be greatest. The heavier snow, along with reduced visibility, should progress east-southeastward this afternoon into the evening hours (per 12Z HREF calibrated guidance).

 

Edited February 16 by Undertakerson2.0

[Jim]

53 minutes ago, clm said:

I thought PA used cinder.

They did when I was a kid. It worked. Of course, it got tracked into the house, and Mom was not happy about that. Of course there were rules about wiping shoes and boots and taking them off, but that didn't always happen. I haven't seen cinders in this area for decades.

[Pghsnow]

2 minutes ago, Undertakerson2.0 said:

This is from Pgh AFD and it expresses the criteria is 6, not 4-6 

https://forecast.weather.gov/product.php?site=NWS&issuedby=PBZ&product=AFD&format=CI&version=1&glossary=1&highlight=off

I understand the criteria. In Pgh our criteria has always been 4-6 inches. I have seen 3-6 inches have a WSW in the past. They are saying some in the Pgh area are getting 6 inches just not everybody. So that should still fall under WSW for the Pgh area because there will be at least 6 inches of snow in some places. 

[Burr]

Updated

 

[LUCC]

Clouds in the distance slowly creeping in from the W/SW.