You would think that now that it's Saturday we can all relax. ;-)
Buuut noo.... Sandy and "Frankenstorm" had to go screw things up. Not that I mind (well, my kids might), I certainly love a good and weird weather story to go for Halloween. With this post, I'm going to be putting out my first thoughts for actual impacts down on maps based on current model presentation and all that. I had said previously that I like to wait until the higher-resolution / shorter time-frame models get a look at things before I do so-- so now it is time.
But first I still want to get some points across regarding this weekend's weather.
|HPC - Surface Map - Saturday Afternoon|
Our front is stalling out over the WV mountains as sections of it start to interact with the expanding outflow of Sandy. The rain showers associated with our front are on the back side of it (as opposed to out ahead of it). I've been saying this for a while, but it's an important point to keep stressing. It is like this because the showers are being driven out of the clouds by ever cooling air. Notice the area of high pressure to the west. 1030mb is about the highest pressure we've seen in months, so it is a force on this map too.
Whenever showers are being generated in this fashion (with one air mass doing all the talking instead of a convergence clash of multiple air masses), the showers that result are often prickly and patchy. What I mean by this is that it's not going to be everywhere all the time, and a heavier shower will be restricted to just tiny cores here and there that shouldn't linger over any particular place for very long.
Here's the anticipated rainfall amounts through tomorrow morning:
|HPC - Rainfall Projection - Through Sunday Morning|
This is a very manageable situation. At any other time, by itself, this sort of event would not dissuade folks from sampling all the wonderful things we've got going on this weekend-- in particular the C-K Autumfest (Ceredo-Kenova), Halloweast (Charleston), Festivall Fall (Charleston), Harvestfest (Point Pleasant), and I'm sure many others I'm not remembering off the top of my head. Sure, temperatures falling through the 50s aren't as pleasant as the 80s of just two days ago, but in any other late October weekend that might be par for the course. So the point on this is, don't be changing your weekend plans because of this whole "Frankenstorm" talk.
In the same vein as the story of the ants and the grasshopper, Saturday is a day for both ant and grasshopper, while Sunday is going to be the best day for making any preparations you may need going forward... So lets take a look at those possibilities.
This "Frankenstorm" has now been consistently presenting itself across ALL models for almost two days now (which is a pretty impressive and respectable run). In most any other situation we would call that a lock. Now, there are still differences in where this storm is going to be when, and all of that matters as far as what our impacts are going to be.
What I'm going to do now, is I'm going to present the image that I think best reflects the storm's maximum impact time locally, together with the anticipated storm track as depicted by each model.
|NAM - Tuesday AM||GFS - Tuesday AM||ECMWF - Tuesday PM|
All the models agree on Sandy's track and it being drawn into the US coastline somewhere between the Delmarva (Euro) and NYC (GFS). When we get to the shorter time-frames, I often prefer the higher resolution models, so the NAM will have a little more weight here, though you have to also respect the others because of their consistency.
Every one of these models are advertising a major storm with high impact across a large area. All highly populated areas from Norfolk, VA all the way up to Maine, and well inland to the Great Lakes will get a piece of this. Now, here are what I see as these impacts:
|"Frankenstorm" Impacts - Coastal Flooding / Storm Surge / Beach Erosion|
Sandy is a tropical system, so we have to watch for storm surge when this thing comes inland. Also, it will be channeling in tons of moisture coming in on east winds. And, this storm will be doing so for at least 3 days(!) All beaches in the areas in orange are going to take a beating, and more-so than it would from a typical hurricane impact because usually the storm moves in and out over the course of 12 hours or so. If you know anyone who lives on the coast in the Mid-Atlantic and New England, they need to be preparing NOW, because the proper precautions take a lot of time. These particular impacts are drastically less as you get inland, but most folks who live out that way are already aware of how vulnerable they have been in the case of a coastal river going out of its banks, or water making it farther to their region than the coastline itself because they are in a low-lying area, etc. etc. These impacts begin on MONDAY and will continue through WEDNESDAY, and will be felt the greatest whenever the storm's orientation is such that the wind comes directly onshore. An off-shore wind will actually help you out instead. The greatest impact for storm surge flooding will be directly to the right of Sandy's forward motion as it makes landfall (just like blowing through a straw across a plate of water, these constant winds will actually elevate the ocean level itself as it comes in, with waves over-top of that).
|"Frankenstein" Impacts - Flooding|
This would encompass river flooding and wide-area flooding (not street flooding, spot culvert/drainage issues, viaducts, etc...) This is also not the entirety of places that will receive rain (that's just about all of us). These are the places where Flood Watches most likely would go up in association with this storm, particularly in the darker green. Upslope winds play a huge role in concentrating precipitation (rain or snow), so the northern Appalachians have a little up-tick in threat as well as the "Lake-Effect" lands of western New York. The most widespread problem for this would be in New Jersey, the greater Philadelphia area, and further to the low-lying areas in the Del Marva peninsula. These places could see more than 5" of rain. A mitigating factor in all of this is the prolonged nature of the storm event, allowing for at least some component of the rain to drain out while new batches arrive. The fallen leaves make this more difficult though, and any blocked drainage will cause localized problems real quick. As it stands right now, our tri-state area is also going to get a lot of rain, but (a) it's been pretty dry as of late, so we're prepped to absorb a bunch before problems arrive; and (b) it's a long-lasting event, so it's a still an open question as to whether we get the intensity necessary to go from plain soggy to area flooding. (but, keep in mind that localized culvert/poor-drainage/street flooding is always possible when leaves are on the ground). The potential for these impacts to arise will begin at the landfall site, and then expand outward to the other areas as rain continues to fall. It is possible this impact may still be a threat for some areas through Thursday depending on how the streams react.
|"Frankenstorm Impacts" - High Winds|
This is a much more complicated forecast element, but it represents where I think the best locations for experiencing winds of 40mph or greater for several hours during the event (not necessarily consecutively). This would include areas closest to the projected landfall site, as well as elevated areas that at one time or another would find themselves oriented perpendicular to the expansive circulation of the system. Areas that aren't in the pink will still see winds (this is a very windy storm), I'm just highlighting places where I see the wind being most impactful. These impacts begin on Monday for the landfall site and elevate areas near and north of it, followed later by the other areas well inland, picking up areas along Lake Erie and our Appalachians on Tuesday.
I think that's everything, right? ;-)
Oh yes, almost forgot...
|"Frankenstorm" - Snowfall Impacts|
Just like the Thanksgiving Blizzard of 1950, this storm seems made for the Mountain State. The strong windflow hitting the mountains from the west channels strong vertical velocity that overcomes many of the factors that typically limit aggressive snowfall accumulation (namely: temperature). The ground is still warm however, so it will take a heavy snow in order to stick. Otherwise, it will be flakes in the air that melts quickly off the grassy surfaces should the intensity go down. Areas in the lightest blue are where I expect to see at least some snow of some sort, whether it be flakes in the air or grassy accumulations. The middle shade indicates places where I would be thinking about "Winter Storm Watches" and the potential for several inches of accumulating snow. This is highly elevation dependent, so there will be many dips and bumps in the reality when things get going. This would include areas east of I-79, all the way down through the southern mountains along Corridor-G. The darker blue represents the potential for dangerous snowfall accumulations. My particular preference for the "bulls-eye" in the entire region is the Canaan Valley area, but from the mountains of Preston/Garrett county all the way down to Snowshoe Mountain have the potential for ridiculous snowfall amounts. We are talking over a foot of snow, with the highest terrain getting to the 2-foot range. It's a good thing up that way that the leaves are falling off the trees (as the winds will further enable it), because massive power outages would ensue. As it is, you can probably imagine that power outages are possible in areas that get heavy snow and/or the gusty winds. The first flakes will start switching over in the mountains in the wee hours of Monday morning, while areas closer to the Ohio River would have to wait until Tuesday to get flakes to mix in. Once we go to snow, we will see the potential for flakes to fly as long as the intensity stays up, right through parts of Wednesday. In my opinion, folks at ski-country elevation in the West Virginia mountains should be taking precautions TODAY and SUNDAY for what you may need should you find yourself snowed in without electricity. This is NOT for a whole lot of people, and those that I'm targeting are already seasoned veterans when it comes to heavy snow events, winds, and weird weather. So lets keep the panic down if we can :-)
[IMPORTANT NOTE]: This is not my final say on this snowfall forecast, nor on the local impacts of this large storm, but it does represent my assessment of the impacts of "Frankenstorm" through the entire region, Mid-Atlantic, and New England areas. This storm is still a long way away, and typically the "Final Call" wouldn't normally even come until something like the 12-hours before the first flakes fall. There is still the potential for changes in this forecast (even large changes) depending on how future model runs dictate. As it is, we're talking about a rare once in 20-years kind of thing. There are reasons why things like this don't happen all the time, or fall apart at the last minute. These ingredients just aren't supposed to combine in this way-- it's quite the threading of the needle.
If anyone has any questions or comments on this, please feel free to write them below, and I'll try to get to as many as I can. We'll be talking about this storm for days-- and probably much longer than that if this thing verifies.
The tracking maps below are for your use. They update all the time, and provide valuable weather information that is current.
Update (6:00pm) - The National Weather Service in Charleston has expanded their Winter Storm Watch field to include some more of the mountain counties (down to Raleigh County).
This is in line with what I've been saying about the places that look to be impacted the most by snow from this storm. Now, the National Weather Service in Pittsburgh oversees Preston and Tucker counties, but have issued Flood Watches for the area, and NOT Winter Storm Watches. My thoughts have been that Preston, Tucker, and even Garrett County should have Winter Storm Watches as well (but I don't make those calls). The thing about Preston and Tucker counties is that they are bi-sected by the Cheat River, and the eastern side of the counties are above 2500' while the western sides are much lower. At this point, I still think areas like Terra Alta, Wisp, and Canaan Valley still can get wallopped by this one, and should already be taking precautions.
Later tonight, or early tomorrow, I will be posting a blog update that will have some of my own numbers with it. The first flakes fall in the mountains as early as Late tomorrow, while the lowlands wait until Monday or later. (This watch/warning information will be updated in the tracking maps below).
|Regional Radar/Satellite with Warnings Tracking||
From the Storm Prediction Center (below): Click For a Larger Image
|Activity Overview||Storm Outlook||Watches||Potential Watches||Storm Reports|
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!