The March Lion Storm

[snowstormcanuck]

13 minutes ago, Toronto4 said:

According to the link below (8th member of the Euro ensemble run), there are some amped up 12Z Euro ensemble members with over 1" QPF for the GTA. And also some whiffs and some in-between.

https://weather.us/model-charts/euro/7cde42424525268bfe98328ed2d8f162/m8_acc-total-precipitation/20180303-0600z.html

And the 18z GFS with a raging rainstorm. My goodness. 48 hours out and the divergence is increasing. How do you forecast for this?

[snowstormcanuck]

BTW Weather.us is a fantastic site. Thanks for pointing it out T4.

[Stebo]

DTX's take on the potential.

Quote

Cooler air flooding into SE Michigan Wednesday night on the newly
developed northeast low level flow will help set the stage for the
next round of precipitation, mainly Thursday and Thursday night. The
key to the forecast for this time period will be tied to the
evolution of the low moving out of the 4 corners Wednesday night.
Model 500 mb dprog/dt indicates the NAM and GFS solutions are stable
with respect to the Pacific NW upper low and the central Canadian
trough while showing variability on the strength of the 4 corners
short wave while entering the southern Great Lakes Thursday, both at
the surface and aloft. The general trend over the last few model
runs is for stronger intensity and a farther south track that still
places SE Michigan in a favorable location for substantial
precipitation, beginning as rain during the day followed by a
meaningful transition to snow from north to south during the
afternoon into Thursday night. Larger scale characteristics that
favor a stronger low pressure system include the short wave location
within the powerful southern stream upper jet along with larger
scale height falls impinging on the upstream side moving in with the
wave from central Canada. The southern stream upper jet is projected
to be pushing 170 knots Wednesday night into Thursday while the
northern stream wave presents access to a generous PV reservoir as
the 4 corners low approaches. The wildcard in both the intensity and
track of the system concerns model QPF and the likelihood that the
high amounts in the NAM and GFS are leading to over-development of
the low pressure system and a farther north/west track. Both 12Z
runs indicate a component of low level PV production tied to the QPF
maxima which suggests the strength of the system is being influenced
in the low levels by associated latent heating. The problem is that
convection extending from the Gulf Coast through the Tennessee
Valley will have a big influence on mass fields and moisture
transport from there into the surface low track and therefore QPF
over Lower Michigan remains highly uncertain, and therefore so does
the track and intensity of the system. Potential higher impacts from
both rainfall and snow accumulation will also be strongly dependent
on the location of mesoscale forcing features supported within and
dependent upon the character of larger scale system. This is not to
say the higher impact solutions won`t happen, just that the forecast
will ease into a higher end scenario as better evidence develops.
Minor forecast adjustments this cycle include a cooler temperature
trend for the Tri Cities and northern Thumb and some light snow
accumulation during the afternoon as it appears a track north of the
Ohio border is unlikely. This also favors a little earlier rain to
snow transition across the area while using a composite QPF before
precipitation diminishes during the evening. Not much mixed precip
is expected, mainly just a transition from rain to snow.

 

[Stebo]

GRR's take

Quote

A low pressure system near Lafeyette IN will continue to
strengthen as it moves east to southeast of Cleveland by 00Z
Friday. Steadier rain showers associated with this system will
develop over our southern counties during the early morning hours
Thursday.

12Z guidance consensus lower level critical thickness tools and
fcst soundings/thermal profiles suggest that this rain will
gradually become mixed with and then change over to wet snow
through the day Thursday.

This transition will be aided by dynamical cooling processes as
pcpn potentially becomes heavy from mid to late morning through
the afternoon aided by vigorous mid level omegas through the dgz
in response to strong mid level frontogenetical forcing.

It is a very complex forecast due to very significant short range
and high resolution computer model guidance discrepancies in
terms of placement of heaviest qpf and how much snow will fall.
Experience tells me that given strong ne to north flow caa
Thursday and dynamical cooling effects that pcpn will transition
to snow sooner rather than later as suggested by 3km nam sim z
guidance.

It`s forecast soundings suggest p-type should already be all snow
in KGRR by around midday Thursday. I continued to trend the fcst
toward a faster transition in p-type from rain to snow during the
day Thursday.

So we expect several inches of heavy wet snow to fall mainly near
to south of I-96 from mid to late Thursday morning through Thursday
evening. Two to six inches of snow appears to be the most likely
outcome for that area but isolated higher amounts are possible where
the most vigorous mid level fgen is most persistent.

The snow in conjunction with falling temps and windy conditions
could potentially all combine to result in some power outages.
Hazardous travel conditions are also likely to develop later in the
day through Thursday night as snow accumulates on roadways and temps
fall below freezing Thursday evening.

 

[snowstormcanuck]

Anybody have any experience with the ICON model? Any usefulness?

[Toronto4]

20 minutes ago, snowstormcanuck said:

And the 18z GFS with a raging rainstorm. My goodness. 48 hours out and the divergence is increasing. How do you forecast for this?

This is crazy. So much divergence. Hopefully tonight's 00z runs will narrow these differences somewhat.

[Stebo]

NAMs 40 for a high and dropping with rain turning to snow

GFS 57 for a high heavy rain maybe thunderstorms with a bit of snow at end

Yeah that is a bit of divergence in models within 48 hours...

[RCNYILWX]

LOT afternoon afd was very low key.

Ideally it would've mentioned potential higher end winter impacts as depicted by the NAMs and Euro among the spectrum of outcomes while also discussing the high uncertainty inherent in these scenarios. The DTX and GRR AFDs are very good.

 

Sent from my SM-G935V using Tapatalk

 

 

 

[HillsdaleMIWeather]

IWX and LOT both went low key, can't really blame them due to the huge uncertainty.

[IWXwx]

This is one those times that I'm glad that I'm not a met at the forecast desk.

EDIT: Any bust complaints with this system will be invalid.

[Snowstorms]

49 minutes ago, snowstormcanuck said:

Anybody have any experience with the ICON model? Any usefulness?

That depends what perspective you view it from. Based on my observations, it's not great for a break down of qpf totals as it fluctuates between amounts quite considerably sometimes. However, its usually half decent in regards to looking at the overall pattern, more specifically the upper air pattern. It did pretty decent with that east coast storm back in early January.

Although I'm very surprised at all the divergence this far out. It all has to do with whether or not the lobe of energy interacts with the s/w allowing for either a partial or full phase and where it occurs if it does interact. Ideally we want the initial s/w to be more tightly locked in and then phase around SEMI. 

[Stebo]

51 minutes ago, snowstormcanuck said:

Anybody have any experience with the ICON model? Any usefulness?

It has been hit or miss but as you get closer in on an event it isn't bad. I would say above GDPS. It is in the Euro/NAM track group.

[Hoosier]

17 minutes ago, IWXwx said:

This is one those times that I'm glad that I'm not a met at the forecast desk.

EDIT: Any bust complaints with this system will be invalid.

Nah, I've already locked in 6+ with strong/damaging winds, and anything else will be a bust.  

Being serious, I'm hoping the track stays south to maximize the wind potential with the winds off the lake.  

[cyclone77]

Those NAM solutions sure would be fun.  12km dumps over 2" of precip total on the QC, with warning criteria snows from here/DVN points north.  A far cry from the anemic solutions it spit out yesterday at 12z/18z.

[Hoosier]

fwiw, 18z RGEM tracks from around SPI to LAF and then south of Cleveland, with a good amount of snow in southern Michigan and southward just over the border.

[cyclone77]

DVN pretty meh with the potential.  Probably gonna be about right, but I would have mentioned the possibility of much higher amounts if a NAM-like solution happens.  It's certainly not out of the question.

 

Based on thermal profiles of the atmosphere, a rain/snow mix should
slowly develop in the pre-dawn hours Thursday over the northwest
third of the area. As colder air gets pulled into the area Thursday
morning, most of the area along and north of I-80 will see a
rain/snow mix. Areas north of highway 30 may change over to all snow.

However, the strongest forcing will be exiting the area as this
occurs. Therefore, snow accumulations for most areas north of I-80
will be well under an inch of accumulation. Some areas in the
highway 20 corridor may see snow accumulations approaching an inch.

[Stebo]

32 minutes ago, Hoosier said:

fwiw, 18z RGEM tracks from around SPI to LAF and then south of Cleveland, with a good amount of snow in southern Michigan and southward just over the border.

At least trackwise the GFS is alone in that manner.

[Malacka11]

Well, like I said a few pages ago, even if it doesn't snow much in LOT, it's still fun reading this stuff and hoping it will. 

[Hoosier]

53 minutes ago, cyclone77 said:

DVN pretty meh with the potential.  Probably gonna be about right, but I would have mentioned the possibility of much higher amounts if a NAM-like solution happens.  It's certainly not out of the question.

 

Based on thermal profiles of the atmosphere, a rain/snow mix should
slowly develop in the pre-dawn hours Thursday over the northwest
third of the area. As colder air gets pulled into the area Thursday
morning, most of the area along and north of I-80 will see a
rain/snow mix. Areas north of highway 30 may change over to all snow.

However, the strongest forcing will be exiting the area as this
occurs. Therefore, snow accumulations for most areas north of I-80
will be well under an inch of accumulation. Some areas in the
highway 20 corridor may see snow accumulations approaching an inch.

NAM is quite extreme (especially 18z)... I'd toss it without thinking twice if it was in the outer periods but it's more like 48 hours out.  Still skeptical, but perhaps it's a case of being on the right road and simply going too far.  That's the thing... rather small changes with this may dramatically alter the outcome.

[Indystorm]

Anyone notice a national radar outage on NWS sites?  I can't seem to pull up NWS radar at any location.

[mfgmfg]

24 minutes ago, Indystorm said:

Anyone notice a national radar outage on NWS sites?  I can't seem to pull up NWS radar at any location.

I am seeing the same thing as well

[snowlover2]

24 minutes ago, Indystorm said:

Anyone notice a national radar outage on NWS sites?  I can't seem to pull up NWS radar at any location.

Yeah its not just you. I get the same thing.

[Ottawa Blizzard]

2 hours ago, snowstormcanuck said:

And the 18z GFS with a raging rainstorm. My goodness. 48 hours out and the divergence is increasing. How do you forecast for this?

This is reminding me of a storm that occurred in late February 2010, towards the end of one of the most frustrating winters I've ever experienced, when pretty much everyone except Canada seemed to be getting lots of snow and cold. I believe that winter saw a deeply negative AO as well. 

[Snowstorms]

10 minutes ago, Ottawa Blizzard said:

This is reminding me of a storm that occurred in late February 2010, towards the end of one of the most frustrating winters I've ever experienced, when pretty much everyone except Canada seemed to be getting lots of snow and cold. I believe that winter saw a deeply negative AO as well. 

**** that winter! I've never seen so many suppressed storms in one winter. Although we have a strong -NAO, the -PNA will help maintain ridging in key areas (SE and central states) to minimize suppressed storms. This is more closely related to the Dec 92 event. 

[snowstormcanuck]

Massive changes at H5 on the 0z NAM. The southern s/w is much flatter. I'm guessing wagons south.

[snowstormcanuck]

The differences at 36 are laughable between the 0z NAM and the 18z NAM. From 3 contours closed at H7 to an open wave. The confluence over QC is less intense though and that's sort of mitigating the suppression.

[RJSnowLover]

Snow dumps on Lower Michigan between HR42 & HR48.

[Stebo]

2 minutes ago, RJSnowLover said:

Snow dumps on Lower Michigan between HR42 & HR48.

Yep, just a bit quicker flatter initially but phases nonetheless and still hits this area.

[Snowstorms]

9 minutes ago, snowstormcanuck said:

The differences at 36 are laughable between the 0z NAM and the 18z NAM. From 3 contours closed at H7 to an open wave. The confluence over QC is less intense though and that's sort of mitigating the suppression.

Drastic changes at H5 this close are beyond laughable. Hard to believe how much inconsistency there is. 

On the other hand, the 0z Nam is pretty sweet!

[TugHillMatt]

The latest SREFs are on board with GFS in giving the heaviest snows to Central and Northern Lower Michigan. I sure hope so.....BUT...I'm sure it will end up being #!#@$#@$@ I-94 corridor of southern lower MI that gets it all. Oops...did my bitterness slip?