Nice Easter begins dry, mostly cool week ahead; remembering the Pulaski tornadoes of a year ago
First off, Easter: You’ll need a jacket or even a light coat if you attend sunrise services, with lows in the 30s to low 40s over most of the area. A frost advisory is out mostly west of the Blue Ridge. But it will warm up quickly by afternoon, so short-sleeves will be in order, with highs mostly in the upper 60s to mid 70s.
Sunday marks the anniversay of the EF-2 tornado that tore through Pulaski and the EF-1 tornado minutes later that hit nearby Draper. The National Weather Service has a good summary of that event linked here. Also, here’s a look back at the Weather Journal blog that day, the next-morning story in The Roanoke Times and a story 2 days later, both by Amy Matzke-Fawcett, and a follow-up analysis on the tornadoes I wrote. Historically, Southwest Virginia usually experiences its worst tornadoes when a very bad outbreak in states to our west bleeds over into our region, like last year’s April 27 tornadoes. But the April 8 tornadoes in the Pulaski area were much different in that they were the only ones reported in the entire United States that day. A unique situation involving a stalled boundary between a cool-air wedge to the north and warm, humid air to the south set up the Pulaski-Draper tornadoes of 2011. (The Roanoke Times covered Pulaski’s remembrance of the tornadoes Saturday at Calfee Park — I will link here when it becomes available.)
Fast-forward a year, and it’s an entirely different weather situation for Southwest Virginia. We’ve talked a bit about some cooler weather this week. Tuesday through Thursday, in particular, will likely be a few degrees below normal (65-66 highs/44-45 lows are Roanoke norms those days, 62/37 for Blacksburg) following some reinforcements of the Canadian air 
that has taken hold of our weather. There will be a few more frost/freeze threats in the coming week, though a “hard freeze” does not appear to be likely. But perhaps the most important feature of the next week or so of weather may be how dry it is. The air coming in off the Canadian prairies is largely devoid of moisture — we’ve seen some dew points in the teens and 20s the last couple of days. Also, the dominant northwest wind flow we’ll see most of this week will prevent Gulf of Mexico moisture from making inroads into our region — a very different event than what occurred in much of April 2011, when we were swamped with sticky, Gulf air. One result of this dry air will be wide ranges between low and high temperatures, approaching 40 degrees on some days between 30s lows and 60s/70s highs. Dry air both warms and cools quickly. Some of the reinforcing cold fronts may be able to squeeze out a bare minimum of sprinkles through lift ahead of the fronts or upslope northwest winds behind the fronts (snow showers in higher elevations west of I-81 stil a possibility at midweek), but total amounts of these are likely to be less than a tenth of an inch, certainly no more than a quarter-inch, through Friday. With any breezes blowing at all, the dry air and increasingly dry surface fuels like leaves and grass will be susceptible to the spread of fires much of this week — Sunday afternoon is of particular concern, and much of Northern Virginia, which has gotten much less rain recently than Southwest Virginia, is under a red flag warning or fire weather watch for Sunday. For now, overall drought is not especially bad anywhere in the state — “abnormally dry” conditions exist for northern and southeastern parts of the state — but that could grow if we get many more weeks as dry as this one. As we move past this week’s cool, dry interlude, high pressure may gradually become repositioned just east of our area, allowing for a stronger flow of warm and moist air from the Gulf of Mexico. Nothing specific yet, but we’ll keep an eye on that for possible wetter weather after this coming week.
April 7, 2012 - 6:44 PM
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Five years ago the very, very warm March (a +6.0 in Roanoke) may have been a curse, because of what the NAO and friends provided this week exactly 5 years ago …. all those sub-freezing mornings in a multitude of places and widespread damage to vegetation.
Kevin, I would appreciate your reaction to the following: this year’s history-making HOT March may be a bit of a blessing. Leaves are out on many of the trees now, at least up here in the Roanoke valley. This may provide a bit of a limiting factor to how bad the fire season will be/ could have been. If we had this extremely dry weather after a normal March and cool first few days of April, the trees would still be bare.
I just looked up the dates of recent Easters, then looked up what the weather was like here in Roanoke. I remember being told by one of my postal customers back in late April 2009 that most of the recent Easters had been cool/cold, and quite few had been wet, too. She was right. From 2002 through 2009, only one Easter had been really warm, 4-16-06. High/low were 74/60, no rain. Easter Sunday on 4-12-09 had reached 65, but the low was 37, so that the mean ended up a -4. Easter in both 2002 and 2005 received at least 0.33 inches of rain. Anyway, you get the idea.
Well, I guess the key was for me to change my job assignment (which happened in early July 2009). Starting with two years ago and including tomorrow, we are going to have three straight really warm Easters. 80/58 on 4-4-10, 88/56 on 4-24-11 (Easter was extremely late last year), and probably 74 or 75 for a high here tomorrow. Watch out for 3-31-13. It will probably snow.
Not sure, Doug, about the effect of trees being leafed out and fire danger. I know there are some forestry pros on here from time to time, would appreciate their insight.
If we were entering a wet period and you asked me about flood potential, I’d know quickly that greening up reduces flood potential somewhat. More water gets pulled out of the ground into trees, and the canopy also deflects and absorbs water that simply runs off on bare ground or fallen leaves in late fall and winter.
Anchorage, Alaska, set its seasonal snowfall record today at 133.6 inches — about 60 inches above normal.
Kinda crazy to think that Anchorage Alaska only gets 70″ of snow a year….that’s not too much more than several places on the Western Slopes… and I would say actually a bit below Snowshoes normal.
The summit of Snowshoe Mountain averages 180 inches of snow a winter. So Anchorage’s record snow is well below Snowshoe’s normal.
Temp here at midnight was a very nice 51*. The lights of Roanoke city are twinkling so much that I cannot remember the last time they were like this. Effect of the very dry air? I reckon so.
Since we are talking seasonal snowfall averages, there is a small village just east of Lake Ontario in very upstate NY, midway between Syracuse and Watertown, that averages well over 200 inches of snow, or at least I have been told that by three people decades apart who were from there (I cannot remember its name). The official Lake Effect Central village of the lower 48 states. It may be the snow capital of North America for a non-mountainous location. if not, it has to be way up there on the list.
No frost here this AM. 53.6* @ 6:30. Wunderground is showing what looks like mixed stuff around Beckly and Monterey.
It was sure nice of those clouds and sprinkles to prevent another freeze last night……….only got down to 35 here.
Ooops, I was wrong. It actually got down to 32.2 sometime after midnight before it warmed up toward dawn.
Looks like the mid level cloud deck with the next frontal boundary interfered with radiational cooling.
I decided to tone down the headline from “picture perfect” to “nice” for today with the AM clouds.
Kevin, did a dry cold front come through around noon or so today? I was down at Draper, and timed it just right. Very little wind for most of the first 16 holes, then it really started to blow for the last two. And was still blowing when I departed at 12:30. It sure is a glorious Easter here in the Roanoke area now. Still extremely good visibility, although not quite as spectacular as yesterday.
And re the fire threat with leaves on trees. I forgot that the trees will soak up more moisture with the leaves out. But the leaves provide a lot more shade so less sun hits the ground, and I think would help in reducing the drying effects of the wind. So I thought overall there would be less evaporation with leaves on trees than without. Could be wrong.
Yes we did have a front moving through today. It helped cause the morning clouds and a few sprinkles and is kicking up a few breezes this afternoon.
I just added 2 or 3 comments in the last couple of days to the Refresh RT blog …. accessible by going back to the thread started on 4-2-12 and clicking on the link. wd, I endorsed your idea of a discussion forum. In another suggestion, which is usually not needed here at all, I offered the idea of being tactful, even when a blogger is absolutely sure he or she is correct about a disagreement.
I posted around a month back that I refused to mix seasons like hauling wood and mowing. If the forecast for this week proves up, I will be forced to eat that post. Since my house cache of wood has been depleted, the wood trailer will have to be hooked back up. Better get you some in too, D. Carol.
For both Monday and Tuesday, from dawn until late afternoon, there are three continuing trends consistently. Temps and wind speed rise, and humidity levels drop, to 21% by late afternoon Monday, and 24% by late afternoon Tuesday. Very strong winds on Tuesday. I have to walk Tuesday, but it won’t be cold. Might be better than having a riding route …. there have been occasions when a wind gust has blown the mail right out of the hand of a letter carrier as he/she tries to place it in the mounted box from the truck.
Well, the mid- to late week cool spell will disappear quickly, as I guess KM has mentioned. Take a gander at today’s computer-generated 6-10 day CPC forecast: http://www.cpc.ncep.noaa.gov/products/predictions/610day/index.php
Kevin any long term trends that you are noticing as of now. Getting married in Cape Hatteras the first week of May. I need some reassurance of good weather and no rain!!!!!!!!!
wdbrand – yep, we filled up the wood racks in the house. I don’t think we will have a fire tonight though. We will just throw an extra quilt on the bed. But later in the week, we may just have to strike the match.
Really windy here today and cool. Started out at 43 F this morning and probably made it to the mid 60′s. As long as the wind keeps blowing I am not too worried about frost.
More in this in a new update later … but red flag warning is up Monday afternoon and early evening for Roanoke and New River Valley eastward for high fire danger due to low humidity and breezy winds.
And according to a Special Weather Statement that I saw somewhere, there was a red flag warning today for some counties in our area from noon until 7 PM. Haven’t heard anything about any new forest or brush fires (although I missed the local news), so perhaps we dodged that “bullet.”
Well, I am mistaken … again. “7″‘s website lists fire crews battled forest and brush fires in the Alleghany Highlands, and saw something about Purgatory Mntn, which I thought is in central Botetourt, NW of Buchanan. Also there were two fires at a house in the 1800 block of Moorman Avenue, NW. I delivered to that street for 6.5 years.
Jason: I think the trend toward late April/early May certainly seems to be leaning warm. While I would also say it probably tilts dry as well, saying what it will be like on your marriage date in the Outer Banks would be nothing mroe than a wild guess. My own wedding happened during the only wet period of a long dry period in fall 2005 … but at least 3 solid days of rain from Tropical Storm Tammy ended 2 hours before our ceremony.
Well, it finally happened. Here is a link to the GFS NAO Outlooks page, and its 4 graphs. Please look at the top graph, “500mb Z (Obs:09Dec2011 – 06Apr2012) NAO Index” The observed NAO levels dating back 4 months. The NAO has not only become negative, it has nosedived to the -1 degree level. First time in at least 6 months. But Friday’s level is probably the bottom, or maybe yesterday’s or today’s. Also check out what the other three graphs are all indicating, a rebound back to positive levels.
The link: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml I hope that I did not just steal what Kevin is about to discuss in his new thread ….. If this predicted rebound of the NAO was NOT about to happen, this upcoming cool spell for Wed.-Friday might have become longer-lasting and much more intense, a la April 2007