Don Slater

Washington Post With An Interesting Article On Norfolk’s Susceptibility To Tidal Flooding

June 1st, 2014 at 11:03 pm by under Uncategorized, Weather

The NY Times did a front page story on this a year or so ago. Now a different take from the Washington Post…and it’s certainly worth reading: In Norfolk, evidence of climate change is in the streets at high tide


Friday Evening’s Tornado Warnings

April 28th, 2014 at 11:13 pm by under Weather

There’s been a minor kerfuffle (not from me) regarding last Friday evening’s tornado warnings.

Here’s a link to the preliminary report on Friday’s tornadoes. The reports are the results of site surveys and radar records by the National Weather Service local office in Wakefield. You will note that the tornado which started at Macedonia, NC began around 7:20 PM. You will also note that the tornado which started in the Edenton area began its destructive path around 7:37 PM.

The Tornado Warnings for these areas were not issued by the National Weather Service until 8:01 PM. So there was a 41 minute delay for the Macedonia tornado and a 24 minute delay for the Edenton tornado. So what gives?

Severe Thunderstorm Warnings were in effect for this entire area in northeastern North Carolina. So residents of these areas should have been watchful for any damaging winds. With these warnings in place, there is always the implication that the storms could worsen. And of course, they did worsen.

Even with the best radar in the world (& it pretty much IS the best), there are winds and even tornadoes that can be missed. Meteorologists rely on radar, but they also rely on public reports of tornadoes. Usually, the National Weather Service radar (which all 3 stations tie into & use) is incredibly accurate in terms of picking up a threat as it happens…or before it happens. This time it wasn’t…and that happens.


Definitely A Moving Target!

March 16th, 2014 at 11:00 pm by under Weather

Just to add a little to what Tiffany posted earlier. I’ve taken some screen shots of “accumulated snowfall” from two different models. I am posting from home, so I don’t have access to the better illustration of the Future Trak models. Nevertheless, these are certainly some of the other models that we look at on a daily basis. First, the GFS:Screen Shot 2014-03-16 at 10.23.27 PMScreen Shot 2014-03-16 at 10.23.44 PMAnd secondly, the NAM:

Screen Shot 2014-03-16 at 10.24.17 PMYou will note that for the Hampton Roads cities, each of these are showing a 0″ to 1″ accumulation across at least parts of the Peninsula. The GFS is a little farther south with snowfall accumulations, but the NAM has heavier accumulations for the Middle Peninsula and Northern Neck. With all that being said…precipitation amounts are likely to be even lighter than either of these models are projecting! A lot of the precipitation just isn’t happening…or is lighter than expected. Additionally, the colder air has just not pushed far enough southward.

Through last Thursday and even into early Friday, the forecast models were showing rain for everywhere except the Northern Neck. But then the Friday afternoon and evening model runs started showing the snow (& wintry mix) farther south. Then throughout the early part of the weekend, the models were just not coming into agreement at all at a final solution for Monday and Tuesday. And as I type this out, Winter Weather Advisories have been dropped for the Peninsula. Those Winter Weather Advisories continue for the Middle Peninsula and Accomack County on the Eastern Shore. Winter Storm Warnings continue for the Northern Neck. And in all of these areas, forecast snow totals have been been significantly pulled back. Just as an example, here is the latest snow total map from the National Weather Service:totalThis storm is definitely a moving target. For the vast majority of us, this will likely be occasional chilly rain! Tiffany Savona has a much more detailed snow total map on WAVY News10 at 11. Jeremy Wheeler will be on the air with WAVY News10 Today at 4:00 AM and Noon. And of course, I’ll be there bringing you the latest Monday afternoon and evening.


Here We Go Again!

March 2nd, 2014 at 12:44 pm by under Uncategorized, Weather

As of Friday evening, preliminary indications were that we’d see this thing hit late Monday afternoon and into the evening hours. It’s now looking much sooner than that…with rain hitting us by around 5:00 AM Monday and quickly changing over to a wintry mix by 7:00 AM and even some snow beginning from Williamsburg northward. The wintry mix (mainly sleet pellets) will likely continue for an hour or two before changing over to all snow from north to south into the Hampton Roads cities by around noon. North Carolina can expect the wintry mix by late morning…changing over to all snow by around 1:00 or 2:00 PM. The height of the snowfall for most of us will likely be in the early to late afternoon.

Here are a couple of variations of the NAM forecast model indicating snowfall totals before it ends early Monday evening.scalenam1nam2You will note the possibility of 4″ to 6″ of snow in areas from Williamsburg through the Northern Neck! I have not included the (later-arriving) GFS model here; this model has indicated far heavier snow than what would be indicated by the ongoing situation. So the GFS is being watched, but discounted for being “off” by a lot. The 7:00 AM European model run will not be complete until mid-afternoon, but earlier model runs fall roughly into line with the above projections from the NAM.

A couple more graphics here. First, here is a snowfall total map from our very capable friends at the National Weather Service in Wakefield:totalsnowThis map is in line with current thinking about the “placement” of the snow (in an east-west orientation), but is somewhat heavier farther south than what the above NAM maps indicate. With the models showing a trend toward farther south and sooner in the day, this map may be an anticipation of the upcoming forecast models continuing the farther south trend. And a slight nod toward the too-heavy GFS. If sleet continues longer before snow begins (& it could), then the above snow totals would likely be lessened somewhat.

Here’s the snow totals map put together this morning by my colleague, Jeff Edmondson:Monday_SnowAnd this is pretty much in line with all thinking on the upcoming storm. One thing to note: When we talk about “ice accumulations” here, we’re talking about sleet pellets and freezing rain, but mostly sleet. Sleet gets easily crushed into the pavement by tire treads creating ice. Sleet is bad enough, but freezing rain is horrendously destructive and especially dangerous on the roads. At this point, freezing rain could be a problem, but not a huge one. With the temperature dropping rapidly on Monday morning, any water falling from the sky and on roads (& especially bridges!) could quickly freeze as temperatures drop to around 27° or 28°. One thing in our favor on all of this is that the soil temperature is in the 40° to 45° range, thus more easily melting any icy stuff that initially hits the ground. Of course with snow pretty much everywhere through the region by early Monday afternoon, tire treads will turn all that snow into ice on virtually all roads.

These maps and forecasts are still subject to change as we draw closer to the actual event, so be sure to stay informed in the next 24 to 36 hours. Jeff Edmondson will be on the air between 6:00 & 7:00 this evening. I will be filling in for Tiffany Savona for FOX43 News at 10 and WAVY News 10 at 11. Jeremy Wheeler and Jeff will be with you from 4:30 AM through 1:00 PM tomorrow. Tiffany Savona and I will take over at 1:00 PM through the evening hours tomorrow.

Here we go again!


January Climate Stats For Globe And For U.S.

February 24th, 2014 at 11:06 am by under Weather

While it’s counterintuitive when we consider our unusually cold January, global temperatures were once again well above average. Here’s the short breakdown from the National Climatic Data Center. Here’s the longer explanation from the same source. As you can see below…while the Eastern Seaboard had well-below normal temperatures, much of the rest of the world was well-above average.

January-2014-Land-and-Ocean-Temperature-Percentiles

Here’s the really counterintuitive part. The United States temperature taken as a whole ended up being just slightly below average; The unusually warm weather in the west counterbalanced our unusually cold weather…and we ended up with a U.S. average temperature that was only 0.1° F below normal.

January-2014-Divisional-Temperature-Ranks-Map


Models Are Lining Up…And Wednesday Evening’s Rush Hour

February 11th, 2014 at 12:12 pm by under Weather

Jeremy writes such a complete blog here that I have little to add. But I’ll do my best.

As of this hour, most of the newer forecast model runs have yet to be completed. One of them (NAM) has completed its run and is painting the following accumulated snow picture:NAM12Z_THURS

I haven’t posted the full “legend” indicating snow amounts, but it’s easy to see that most of the region escapes the brunt of the snowfall. Zero snow or near zero snow is indicated for our area. Keep in mind also that even if we do see things begin as snow, the changeover to rain will melt whatever snow might be on the ground at that point.

Here are a couple other, slightly older model runs depicting accumulated snowfall. First, the GFS model from its 1:00 AM run:GFS06Z_Thursam

And finally, the Canadian (GEM) model from 1:00 AM:GEM06Z_THURSAM

I have not added the 1:00 AM European model because of copyright concerns (from my private source). However, it agrees well with  the above models.

So the models are lining up well indicating that this will not be a major snow event for our part of the world. However, I do have some concern with the timing of the rain/sleet/snow entering the area on late Wednesday afternoon. The precipitation could enter your neighborhood as a wintry mix (even solid snow) for a time before changing over to rain. Temperatures will remain sub-freezing prior to the onset of this precipitation…warming to around 32 to 36 as the precipitation hits. The ground is going to be cold and some of that snow or sleet could stick onto the roads for an hour or two. And that hour or two closely coincides with the evening rush hour Wednesday. Right now, my thinking is that much of the Hampton Roads area (esp. South Side) will be just fine on this…with a quick transition to all rain, thus wet & not icy roads. In fact, much of the South Side might not see any solid snow to stick on the roads at all…just a rain/sleet mix becoming all rain. For the Peninsula cities though (say, Oyster Pt. & north), this could indeed begin as a snow/sleet event for a time…sticking on the roads very close to the evening rush.

This is going to be a close call…and if I’m in error on this, I’m erring on the public safety side of things. At this point, the models continue to lean toward a “not frozen roads” solution. But it’s close! Everyone should be watching closely for the details on this one all the way into its onset late tomorrow…near the evening rush hour.


Surprise…SURPRISE!

January 30th, 2014 at 11:59 am by under Weather

To add a little to what Jeremy has written.

As of 11:00 last night, I had predicted overnight lows to be in the single digits inland to the low teens inland. Of course, the temperatures dropped to from around -4 to around 7 or 8! So this was indeed a “blown forecast”.

Here’s a little of what was going on prior to the 11:00 newscast. Mid and high-level cloudiness was covering the region and greatly slowing the temperature drop. That cloud cover was just not budging either. With that cloud cover not clearing out, temperatures had not dropped all that much during the evening hours…basically dropping from daytime temperatures of around 23 to around 12 to 19 by late evening. In other words, no real indication of “plummeting” temperatures.

Here are a few images from last night. I screen-grabbed them off the web so image quality is not terrific, but you’ll get the idea. This first satellite image is from 10:30 last night. You will note the cloud cover over southeastern Virginia and North Carolina; that cloud cover had basically not moved since late afternoon yesterday. You might remember yesterday’s brilliant sunset. Temperatures were in the upper teens to around 20. 330This second satellite image is from 11:30 PM (right at the end of the newscast…uh-oh!). The cloudiness has finally shown signs of eroding. 430Here’s the satellite image from 12:30 AM. Cloud cover is basically gone from southeastern Virginia. With clear skies, dry air, no wind, and extensive snow cover…temperatures can now plummet!530

And plummet they did! Here are 2 temperature records from National Weather Service reporting sites (screen grabs again). The first from Suffolk. You will note under the Temp. column, the -4 readings at 6:15 and 7:35! For the 11:00 (10:55) reading, it was 12 degrees. That’s a 16 degree drop by 6:15:sfqHere are the temperature records for Norfolk for pretty much the same time frame. The 11:00 reading was 18 degrees. While the 3:51 reading was 7 degrees, we actually bottomed out at 6 degrees (presumably around 4:00 AM). So that was a 12 degree drop between 11 PM and around 4 AM!orfRapidly clearing skies, no wind, dry air, and heavy snow cover. All resulting in a very rapid temperature drop…and that blown forecast.

We’re still on track to see highs in the low 30s today. We’ll see at least some of that snow melt today…a lot more by the weekend!


ModelPalooza

January 27th, 2014 at 11:12 pm by under Weather

A “ModelPalooza” coming up in this blog post. Tiffany posted a bit earlier in the evening about the likelihood of significant snow in the area…and most especially for the South Side cities and into eastern North Carolina. The question is not, “Will we get snow?”, it’s, “Where will the heaviest (as in, VERY heavy) snow fall?”. Will the crazy amounts of snow hit mostly in North Carolina and miss most of the South Side? Or will the bulls-eye of heaviest snow be over the South Side cities (big population!)? Regardless, eastern North Carolina is going to get the heaviest snow. Virginia will get snow greater than the snowfall of last week.

As I write this, the 00Z (7:00 PM initialization) models are not entirely complete, but let’s go with what we have thus far…and some of the earlier models. Here’s a 00Z model that isn’t totally complete, but it’s the latest…and does run through the entirety of the storm. This graphic is precipitation (just rain…even though it’s not going to be rain). We’re looking for the heaviest area of precipitation:0Z_HiRes

You will note that the heaviest area of precipitation (in yellow) is south of the Albemarle Sound. So with this particular model run (4km NAM), the heaviest of the heavy snow stays south of the Albemarle Sound. However, the blue colors reaching all the way into Virginia still indicate a snowfall in the 4″-6″ range into the Hampton Roads Cities.

Here’s a graphic of actual snowfall from the 18Z (1:00 PM initialization) GFS model:

18z_gfs2Instead of the heaviest precipitation occurring south of the Albemarle Sound, THIS model has the heaviest snowfall north of the Albemarle Sound and well-into the South Side Hampton Roads cities. And those snowfall amounts are in the 8″-12″ range all the way up into Virginia Beach! I’m not buying into those heavy amounts all the way up into Virginia Beach. However, 8″-10″ is certainly possible into North Carolina…with 6″-8″ possible into Chesapeake and Virginia Beach.

The EURO model has been all over the place in the past 5 days (yes, no, yes, no, maybe, YES, YES!). The EURO model only comes out twice a day (7:00 AM & PM). The 00Z EURO has yet to complete its run, so we’ll look at the 12Z model run:

12Z_EUROThe colors here are a little different, but the snowfall estimates are a bit more to my liking right now. You will note that the heaviest precipitation (darker purple) is south of the Albemarle Sound. But we’re still looking at 10″-12″ into North Carolina and 5″-8″ into parts of the South Side cities.

Here are two more 12Z models. The NAVGEM (NAVY) model is shown first…and the GEM (Canadian) immediately follows:12z_NAVGEM

12Z_GEMThe NAVGEM shows the heaviest (but not huge) accumulation south of the Albemarle Sound…and the GEM shows 12″-16″ of snow just north of the Albemarle Sound.

It’s going to snow. And it’s likely that that snow will be heavier than last week’s snow. The question remains as to where the huge (10+”) will fall. Newer model runs will hopefully reach consensus as to where that “monster snow” will fall.

Timing seems to favor the snow spreading northward across North Carolina from around 11:00 AM through 2:00 PM. Snow will reach the state line and continue northward into Virginia from 2:00 and on through the afternoon. I fully expect that snow will be falling from the sky throughout the Hampton Roads cities by 5:00 PM. In fact, the heaviest snow is likely to fall between 5:00 or so and on to past midnight.

Stay with us. Jeremy Wheeler will have more on WAVY NEWS 10 Today and at Noon. Tiffany Savona and I will be there for you at 5:00, 5:30, and 6:00…and likely throughout the evening hours.


Active Weather Ahead!

November 21st, 2013 at 10:49 am by under Weather
Two big weather events within the next seven days.

1. Look for a pleasant warming trend into Friday and early Saturday. Temperatures should drop later Saturday and continue that drop into Sunday. Highs Sunday only around 40! Wind chills will likely be in the 20s and low 30s.

2. A storm is likely to develop over Georgia pushing northeastward off Cape Hatteras on Tuesday and especially into Wednesday. It’s too early to nail down the storm’s exact effects yet, but it does look like a very rainy, breezy day on Wednesday. The storm does look like it’ll move quickly so as not to provide significant tidal flooding, but it still looks nasty! Here’s an NWS graphic depicting total rainfall from Tuesday through Wednesday. Note the red stripe of 3″+ through our area. Again, it’s too early to be exact…but one to watch.

Screen Shot 2013-11-21 at 10.32.57 AM

Relative To Space…

November 20th, 2013 at 1:20 pm by under Uncategorized, Weather

Quick post…

My 2nd cousin (Karen Nyberg) was on board the International Space Station for nearly six months. Today from 2:00 to 3:30, NASA is allowing the media to hold satellite interviews with Karen. The interviews are from all over the country and will be in five minute intervals. My allotted time is from 3:25 to 3:30. I’m not sure yet when my interview with Karen will actually hit the air.

You can watch the hour and a half worth of live interviews on NASA TV.