Model Mania (Snow?)

January 27th, 2010 at 10:19 am by under Weather
Snow Hope Index

Snow Hope Index

Ok I promised a new blog so here it is.  I thought about waiting for the morning models to come in, but I didn’t want to wait that long.  There’s my latest snow hope index.  It’s at a 7.  Odds are that this will go down tomorrow, and then back up on Friday, but we’ll see.  Here’s the latest thinking about this system:

The Basic:  An area of low pressure will move up from the Deep South Friday into Saturday.  It will butt-up against some very cold air coming out of Canada on Friday.  Snow showers in Central Virginia are a good bet.  There is a chance for accumulating snow in the metro (hence the snow hope), but there is also a possible rain/snow mix in the forecast for a period.   Scattered snow showers are expected late Friday night while the whole atmosphere moistens up from top to bottom.  Then the mix would come in to some part of the viewing area early Saturday.  As the low moves offshore Saturday, the cold air will push back south and snow showers will take over.  Then the upper level low comes into play and can make for some light snow showers Saturay afternoon/evening.  Here’s the latest forecast that I put together regarding the low pressure area at the surface:

Weekend Weather

Weekend Weather

This forecast track can easily change.  I’ll discuss some of the computer model trends below.  Warning…it will be detailed.  I will mention some cities in here, but they are more for cutoff points rather than specific forecasts.  I can do more city by city when we get closer to the event. 

The models (detailed):  I first looked at the Canadian model.  It has some light snow arriving late Friday night through a good portion of the area.  Very light stuff though.  Then Saturday morning it shows heavy snow near the Virginia/North Carolina Border.  It looks like a mix from Virginia Beach Southward.  Saturday afternoon/evening the low moves offshore and we get some moderate snow inland with a possible rain/snow mix in the metro.  Rain/sleet for the Outer Banks at that time.  We dry out later that night. 

The overnight run of the GFS model has some rain/sleet/snow in North Carolina Friday night with virga over Virginia.  It has the light snow coming in overnight with a rain/snow mix over northeast North Carolina.  Light snow in the metro and heavy snow in Central Virginia.  At that time the low is over South Alabama and stretches over to South Carolina.  By Saturday morning it looks like a mix in the metro southward with heavy snow from about Suffolk northward.  It would probably be the heavy/wet variety, but that’s a guess.  By the afternoon the GFS has some moderate to heavy snow in the metro and north and west of here.  The low then stretches from Florida up to just offshore of the Outer Banks.  The upper level low then takes the baton and produces some light snow Saturday afternoon/evening as the surface low moves away.  Here’ s the place that I go to look at the GFS and NAM models.  It’s NCEP

To me the European model looks further south and is more upper level dependent.  It looks like less snow from the most recent model run, but maybe I’m not looking at a good source.  Here’s the link that I use: European.

(update) I just checked the morning run of the Navy model.  It is the driest of the models with most of the mixed precip across North Carolina.  It is not very impressive, but it still advertises some light snow overall.

The morning run of the NAM is coming in now.  Whoa!  It shows dry conditions Friday night and overnight, but then it gets interesting.  Saturday morning it has heavy snow over North Carolina with light snow in the metro.  The surface low over South Georgia at that time.  By Saturday afternoon we could see a rain/snow mix in the metro and in northeast North Carolina.  But it suggests heavy snow from the metro northward and in central Virginia.  The low stretching from Georgia to the southern Outer Banks at that time.  By the evening everybody would see moderate to heavy snow showers as the low moves offshore.  This looks a little supicious though as most of the moisture would come on the backside of the low at that point.  It’s not out of the question, but it does look overdone.  The upper level low would be coming into play at that time.  We’d get the 500mb PVA (upper level spin) coming into play then too.  If this model verifies, then we will be in trouble as we’ll have to measure the snow with a yard stick. 

My 2 cents:  So here’s my latest thinking based off of what I’ve seen so far.  We’ll probably start off with some light snow showers very late Friday/early Saturday.  This will turn into a mix in part of the metro Saturday morning as the low gets closer.  Then as the low moves away the winds go more northeast and the cold air pushes down.  Then we have a chance for snow showers even in the metro.  The upper level low may produce a few light snow showers Saturday afternoon/evening, but it will be on the light side.  This is also when snow may push as far south as the Albemarle.  Some things that could impede snow in the area… If the low strengthens before it moves offshore, then it could throw some more warm air up this way.  That could push the rain/snow line a little further north.  It’s also possible that the low could move further south and then offshore.  That could reduce the snow amounts significantly as most of the moisture would be further south.  But it would also mean that the cold air is in place and then anything that fell would be snow.  Things are getting interesting, but I am not going to get too excited yet. It’s still early.  I’ll start talking about possible amounts tomorrow.  Then it will be 2 days out.  If there is any big updates on the morning run of the GFS, then I may update this around midday.

Meteorologist: Jeremy Wheeler

53 Responses to “Model Mania (Snow?)”

  1. Aaron Graham says:

    The NWS will prob issue a winter storm watch later today, right? The NAM and GFS are coming in line with each other…could this be a big snowstorm?

    1. Jeremy Wheeler says:

      It’s too early for any Watches. NWS would probably wait until Friday. Maybe…maybe Thursday night. Of course that’s their call.

  2. jennifer says:

    Thanks Jeremy for keeping us updated. I am so excited I can’t even sleep. I am a teacher and am glad it is coming on the weekend so I can enjoy the flakes!!!! I live in Hampton and am predicting at least 5 inches!!! Also whenever Jon is away the snow always comes, sorry Jon.

  3. Mark says:

    hrm… so what does this mean for the Williamsburg area? are we on that snow/rain line yet again?

  4. Ryan says:

    Check out the new nam and GFS….4-8+ inches hampton roads and southside. WOW! Big shift in models and looks like Euro will be big winner in this battle. If Euro holds at 12z I think it might just be, maybe, a lock….

  5. Matt Brennan says:

    So if we do get snow , what is the best case scenario? How many inches

    could we potentially get out of this?

    1. Jeremy Wheeler says:

      It’s an estimate, but some inland locations could get up to 10″. Remeber!!! It’s still early, and right now that’s one step above a guess.

  6. Riley says:

    Hey Jeremy– thank you for your thoughtful blogs– I always look forward to reading them when the weather gets interesting! Keeping my fingers crossed for a shot of snow this time.

  7. Mark says:

    I really hope this pan’s out because as of right now it looks promising. It all depends on 2 major things which are how strong will the low be when it passes by and which track it will take. I’m only hoping but which ever area by Friday is supposed to get a decend amount of snow is where 2 of my friends and I will be traveling. Of course once there we will stay put in a hotel or pub watching it lol. Thanks for the model readings Jeremy.

  8. debbie adcock says:

    When you get the latest news on this storm could you please be more specific about what to expect in the HPT/NN area?. All news channels in this area talk about the “metro” area and then shift their thoughts to Williamsburg. There are about 350,000 people in between the metro area and Williamsburg.

    1. Jeremy Wheeler says:

      Hello Debbie. I’m sorry, but at this time I just can’t be more specific. If every model agreed on amounts and the track then I may try it, but it’s out of range (timewise) for even our local computer model. I’ll take a stab at it tomorrow.

  9. Gary says:

    Thanks Jeremy, I honestly think SHI is a 9.5 (based on current models) If current NAM verified with a snow/mix/snow scenerio and the forecasted TOT PCPN values of over 1″ verified it would be several inches in portions of southside and much more n/w of HRBT. Granted, the chance for change is greater than remaining constant. Cold air from the north is a classic set up. Initially, I thoughtthe S/W would kick out and system would weaken, but looks like more energy is forecast to move south out of Canada and prvide some sustaining energy to the system as it moves east (acording to NAM). This is key. Not used to seeing NAM stronger than GFS to this degreee. Will Be fun.

  10. David says:

    Will tides be an issue?

  11. Janet says:

    Let it snow, Let it snow, Let it snow!!!!!!!!!!

  12. Mike says:

    Well if…and a BIG IF 12z Nam verified….my goodness this would be a historic storm…..otherwise most models “suggest” a solid 6-12 in snow over most of the area…aside OBX! and Va Beach

  13. Gary says:

    Why is the term showers being used for non-convective processes? I realize the off/on nature of what shower means helps get the message across to viewers, but it is not what will be happening with this event.
    Overrunning is a stable process and the precip will be intermittent (not showery) or maybe say off/on light snow becoming a mix. Sorry, just a pet peeve of mine from the school days.

  14. Mike says:

    did notice on another channel…whick i want mention…..for respect to WAVY that the biggest snowstorm in history for January is only 9.5 in….December holds the record at 19.8…..February 12in and march14in…..why is it that no top 10 snow in history happens in January….HMMMM!!!! so 9+ inches is conceivable and that would be a january record

  15. Tammy says:

    Thanks Jeremy for keeping us up to date! Please try to include the Eastern Shore in your forcasted amounts. We are loyal watchers and there are times when our forcast can be really different from Hampton Roads.

  16. Ryan says:

    Jeremy, I don’t think your going to be lowering that snow hope index anymore,,,,EURO held course and is COLD here and show 6-10 in ALL hampton roads.

  17. Brittany says:

    Hey Jeremy!
    I agree with Jennifer. Everytime Jon is gone on vacation, we get snow. The Virginia/North Carolina border line always seems to be on the edge. I’m hoping the NAM model is right. It’s been a while since we’ve seen inches, barely a flurry…lol.

  18. shoregirl says:

    what about the eastern shore? Jeremy, I know you have so much that you have to control but… we really rely on WAVY up here. We don’t have any other local news. Are we in the rain area or snow area?

    1. Jeremy Wheeler says:

      You could see some Saturday night as the upper level low comes across and the surface low just sits offshore. I won’t give amounts until tomorrow though.

  19. Sheila says:

    Thanks for the information. I was born a raised here and really miss the nice snowfalls. I even drove to Annapolis last year for the last snow storm because we hadn’t had any all year. I hope this one isn’t another disappointment!! Maybe I will just have to go to Williamsburg from the beach this time!!

  20. Paul says:

    Let me add my thanks for your excellent reports on this blog. I’m looking for a good snow like everyone else…but I appreciate your thoughtful opinion on this storm. BTW, is Don cringing at your 10 inch accumulation “one step above a guess” yet? Either way, keep up the good work.

  21. Geoff says:

    18Z Nam is hammering Hampton Roads with snow

  22. wayne says:

    jeremy what about franklin……

  23. Donna says:

    Doesn’t it always snow when Jon Cash is out of town?

  24. Sharon says:

    Where is John Cash. Not that you’re not great, just wondering where he is. He always gets so excited when there’s snow in the forcast.

  25. Jason says:

    I live in north suffolk n can u predict how much snow we could bet here

  26. Stuart says:

    I don’t know why the Tv weathermen use the GFS the Euro has been much more dependable this winter season. The GFS make way to many mistakes. You will see the GFS start pushing the storm North by the next 2-3 runs. Use the Euro or the JMA Model. They are much more in line about what may happen. I still see a big Snow for Hampton roads. Since I live in Northern Virginia I hope we atleast get a 3-6 inches up here.

  27. Jennifer says:

    Hi Jeremy,
    I’m from Lake Tahoe and feeling a little home sick from hearing about all the snow they have received. So If you could just twitch your nose or wave your magic clicker to make it happen that would be great. Thanks so much. P.S. Two to three inches would suffice.

  28. Mamie says:

    Can you define the snow hope index? Is it a scale from 1-10? With 10 being 100% probability there will be snow

    1. Jeremy Wheeler says:

      It’s a product of Jon Cash’s actually. It is a scale of 1-10 for a chance of accumulating snow in the metro area (Hampton Roads) of an inch or more. One year I called it the snow hope/no hope index for more balance. Didn’t have as nice of a ring to it though.

  29. Charles Andrews says:

    Hey Jeremy, Don’t forgot the folks of Southampton County. We are also curious, about the impending ” snow storm”. Thank you.

  30. Lindsay (Williamsburg) says:

    Ok don slater its time for you to write a blog!!

  31. Joweather says:

    So, current models look like HPT/NN could get 4-8 inches. I know you can’t say yes or no but….what do you think Wheeler? Is that what the most “ACCURATE” models are leaning towards. And significant snowfall for the area..but VA Beach could get a mix with possibly around 1-3″ like most of Southside. West of Williamsburg could get crippled with 6-12.” Sound about right? I have been studying the models for the last few days…just looks like a big one.

  32. Joweather says:

    Come on man….Am I on the right track here though? I’m an aspiring meteorologist trying to call this big one, haha. Tell me what you THINK as someone who has lived here and also knows the liklihood (or lack their of) of such an occurence happening here. NO ONE is certain in these storms…We all know that. But I’m just curious to as what you think at this moment. A stab in the dark you could call it. What’s your gut telling you?

  33. Jeff says:

    If I’m reading maps right, the storm keeps slowly inching further south and I’m starting to think we won’t get much at all on the peninsula if it keeps it up. That would be some kind of luck. Barely miss out to the north on the last big storm and barely miss out to the south on this storm. Heartbreaking… I really hope I wake up in the morning to news that the latest maps moved the storm back north a little bit..

  34. OVInfoWarrior says:

    North-West wind = snow.

  35. Joweather says:

    You also said Satrurday night….but I keep seeing maps and graphs that have us starting early Saturday morning or even late Friday night. Waiting for you to come on at eleven. Curious if you could clarify yourself just a little bit. Like I said, just asking for your ‘gut’ feeling on this…

  36. Leigh Keene says:

    I am looking forward to your forecast! I sure hope we get accumulation snowfall in Edenton, NC!!! Be sure to include NC in your forecast.

  37. Cindy says:

    Ok….what about the Eastern Shore? Seems like we are left out of alot of forcasting done for Hampton Roads….please don’t forget us , Jeremy :)

  38. LetitSnow says:

    LOL, you guys are so playing it ultra conservative. It’s time to sound the alarm and give people time to prepare. Tomorrow is Thursday, with a possible significant storm in the area, what are your thoughts on accumulations?

  39. Heather says:

    I am just so excited I can not stand it! I know I often get my hopes up, but I really have a feeling about this one. I just really want my daughter to be able to build a snowman. She asked for snow from Santa Claus and well… Santa brought her a “snow man kit”! So, she BELIEVES it is going to snow this year. I have to go with her on this one; I wish that I could believe more like a child these days! ;)

  40. Ryan says:

    6-14 inches looks like a good bet now for southside…WOW Biggest snow since 1989???

  41. Gram says:

    NO!!!!! :(
    I am SO sad that I have to go to South Carolina this weekend!!!
    It actually seems like Williamsburg will get it pretty good!!

    And just to clear some things… Williamsburg itself NEVER gets included in the significant snowfall area. They always say “Possibly as far east as Williamsburg” but it’s pointless. We always get the same amounts as Newport News and in some rare cases an inch more. It’s really Toano, a city north of Williamsburg, that occasionally receives more snow than most local areas.

  42. Gram says:

    hahahaha and yes!! I think it is hillarious that the die hard snow lover Jon Cash is never here when HR gets hit hard!

  43. Liza says:


  44. Tinika says:

    Come on Jeremy…waiting for another blog…lol

  45. Jim says:

    Got my fingers crossed. Hoping Western Suffolk will see a lot.

  46. Sheila says:

    Come on Jeremy, where is your detailed update now that a watch has been issued? I really have my hopes up on this one!! Good to hear from other people here that feel the same way!!

  47. Kenna says:

    I LOVE SNOW! Bring it on! If we get a fun amount, that would be the best birthday present ever! I’m from Montana so I miss having snow!

  48. Jeff says:

    I was hoping to find out why Wavy 10 was scrolling on Fri. eve. that elizabeth City was possibly going to receive 10 to 15 inches ? That seemed very high even for other areas. Yhank You !

Leave a Reply