UPDATE 8:15 AM, 4/11: Fire risk by day, freeze risk by night as dry, cool Canadian air mass tightens grip on SW Virginia
UPDATE 8:15 AM, 4/11: Let’s just roll this over a day, except it will be considerably cooler today (50s for highs, some 40s), just a little less windy (though still windy and dry enough for high fire danger) and likely even colder by Thursday morning, with freezing temperatures over a much wider area (winds and clouds held temperatures a little above freezing in most of Southwest Virginia overnight) and a frost threat if winds die down in time. Link here and scroll down for the latest patchwork of freeze and fire advisories. A rapid warmup is expected over the weekend with highs in the 80s by Sunday through Tuesday. END UPDATE
UPDATE 7:45 AM, 4/10: The freeze watch has been updated to a freeze warning for early Wednesday generally along and west of the Blue Ridge, including the Roanoke and New River Valleys. I added an inset of this unusually colorful National Weather Service map splitting the region between blue for the freeze warning and red for the red flag warning, mainly because it is interesting. However, the map linked here gives a little bit more accurate view, showing the purple region in the middle where fire and freeze threats overlap. END UPDATE
Red flag warnings for fire danger and freeze watches overlap across Southwest Virginia. It seems very odd at first glance, but really, it has the same root cause: A dry, cool, Canadian air mass being shoved into our region by the circulation of high pressure to the west and low pressure to the northeast. Tuesday is again expected to be a breezy to windy day as the strongest in a succession of dry cold fronts — mostly dry, in this case, as I’ll explain below — pushes through. This is the front that will bring the coldest weather of this April cool snap, with near-freezing low temperatures possible Wednesday through Friday mornings, and highs that may not reach 60 on a couple of those days. On Tuesday, it will add more wind to a very dry situation in the air and on the ground, putting the region in critical fire risk according to the Storm Prediction Center (the same folks who issue tornado watches, in case you wondered). An existing large fire in Craig and Alleghany counties will likely continue, and new fires could quickly get out of control anywhere they are started. That’s why the red flag warning has been renewed in 
much of the area for Tuesday afternoon and early evening — the warmer part of the day has the lowest humidity with greatest difference between temperature and dew point, and winds will pick up a bit during this time as well. Wednesday may provide another period of at least somewhat heightened fire danger, but after that, winds will diminish. That will reduce the fire-spreading threat but may lead to more widespread frost and colder temperatures by Thursday and Friday mornings.
Northwest wind flow behind Tuesday afternoon’s cold front may trigger some light showers in eastern West Virginia and perhaps the far western rim of Virginia as moisture is squeezed out as the winds blow over the slopes of the Appalachians. By early Wednesday, some of what is showering may be snowflakes. A disturbance passing through Wednesday night may be enough to trigger ground-whitening snow in the higher elevations of eastern West Virginia, and perhaps a few flakes may drift into higher elevations across the state line in Virginia, too. Moisture is scarce, though, so amounts will be very light, with no more than an inch expected. Downslope wind flow should dry up any rain or snow showers before they can get into the Roanoke and New River valleys.
By the weekend, a rather sharp warming and gradual moistening trend will begin as high pressure shifts off the East Coast and turns our prevailing winds more to the south and southwest. 80 degrees is possible by Sunday or Monday.
April 9, 2012 - 11:14 PM
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In regard to what I posted on Sunday, it is obvious now that the extremely dry air and huge winds with daytime temps in the 60s are much, much more important than whether the trees have leaves or not.
I am practically same temp at 6:30 as RRA, a rarity with clear conditions. Me: 51*. RRA was 50. Absolutely cloudless.
Returned last night from a long weekend camping trip in the South Mountain area of Pennsylvania of the Michaux State Forest where the red sign “Extreme” appeared on their Smoky the Bear sign. It was cold sleeping on Sat. night and very, very windy all weekend, especially on the battlefields of Gettysburg as well as Antietam in MD. Came back windburn and with pollen-embedded eyes. Much of the US seems to be on a fire alert as WeatherBug on my phone kept popping up with alerts for most of places stored in my phone – as far west as Chicago and Austin, TX.
Local author, Michael Abraham, pointed me to the page at http://hint.fm/wind/ in a recent Facebook post. It depicts a beautiful animated visualization of the current wind patterns over the US. Today’s 10 am image is showing an impressive view of the Canadian air that Kevin mentions. You can click to zoom in — then the winds look like growing hair!!
I need to put up a permanent link on that wind map. It’s been linked a few times in comments. It does illustrate wind flow vividly.
It is going to be “fun” trying to cover tender vegetation tonight with the wind blowing as hard as it is. So when will the wind slow down?
I did not think it could frost while the wind is blowing.
You’re right, Another Jason. Frost probably won’t happen till Thursday morning (also answering Doppler Carol’s question about when the wind dies down). But it can get below freezing in some areas with the wind blowing, and that can cause some damage even without frost.
There are freeze warnings out Wednesday AM but you will notice there are no frost advisories as there usually are in the areas just outside the freeze warning. That’s because of the iwnd.
Kevin, when do I get your “all clear” for the weekend?
Just saw that Charlottesville has .03 precipitation for April and we didn’t get much in March. Things are getting dire up here in central Virginia. Doesn’t look like any chance of rain until maybe the 20th if then. Just hoping the pattern breaks soon or we are in big trouble going into the summer. Kevin, are things this dry down in southwest? Parents say they had Been getting rain nearly everyday last week in Giles.
Elliot: How clear is clear? Still looks like a warm front pushes through Saturday — weather service just has cloudy for now, but could be some showers. Moisture is limited, so no soaker expected. Not a big deal. Sunday looks sunny and warm.
Jared: Not as dry down this way, but locations east of Giles did not get as much rain as happened there last week. Dry winds have dried out surface fuels enough that recent rains don’t matter much with regard to fire danger.
That’s enough clear for me. It’s just hard for me to believe weather.com unless you say all’s well.
Will guarantee it will be nothing like April 16 of last year, Elliot! It would take several days to re-moisten the atmosphere enough for even a 30-percent version of that rainstorm.
Hey, HokieTrax LADY (even I won’t forget your gender from now on …. lol), it is wonderful to hear from you. Re the eyes attacked by pollen, you wear wearing some sort of eyewear, right? But I can believe that you still got the problem, even if you were.
I might have tried the following myself, if I had been on walking routes either yesterday or today …. try those close fitting clear protective “glasses” (I don’t know what they are called) that some lawn mowing folks use. Trouble is, to wear them for as many hours as we are out walking (about 7, although that includes the 1/2 hour for lunch), one’s eyes would become way too sweaty, I bet. Maybe a letter carrier could wear them while walking into the wind, then remove them when walking downwind.
Compared to Sunday and yesterday, the visibility is “horrible” today (LOL). I can make out the Peaks of Otter OK, but Apple Orchard Mountain is only a very hazy lump on the horizon.
Elliot, thanks for asking Kevin about this weekend … I am very curious, too. Definitely looks like a winner to me. A brief shower ain’t gonna stop this avid, ancient “goofer.” I may take a little trip to the Front Royal vicinity.
Smoke from Craig/Alleghany fires would likely be reducing your view of Apple Orchard, Doug. Last night at dusk I could make out the smoke plume on the NW horizon from my vantage point in south Roanoke County. Winds more west than northwest or that smoke would be blowing into the Roanoke Valley.
Seems to be an awful lot of the country under a pink colored Red Flag Warning on the NWS homepage. Are these conditions normal for this time of year or is the majority of the nation windy and dry as a whole?
Kevin, in reply to your comment about the possible wind direction that could bring the smoke into Roanoke …. SSHHHHHH!!! :>) :>) :>)
Winds have really died off here in Woodlawn…we hit 25* last sat am and are always 3-5* colder than the forecast calls for…I’m betting on 25 or below here tonight! Got the ferns inside and nothing planted yet. Finally learned my lesson!!
Wind did die down some last night so was able to cover a few more peonies. There was a light breeze during the night but we still got some small spots of frost in the garden on the clover. It was 30 this morning at 6:30 am. Wind has picked up again this morning.
Had a light frost on the roof of the car this morning with a reading of about 35 on the house thermometer. Yesterday while walking through the yard I saw some leaves on a couple trees that showed the telltale signs of damage by the cold, but it was not complete or widespread…yet.
Doug, I wear sunglasses outdoors ALL the time, all year, in every season as my irises do not close up as small as they should. Some people tease me about sunglasses in the winter.
And yes, they help in wind but this wind was the pant-flapping kind. I currently have the Oakley knock-off types and they do fog up in certain weather – usually damp, high humidity type. You haven’t heard from me much because there is so (too) much going on at VT. The 3.2 Run in Remembrance is this Saturday and we are glad for a decent forecast this year. I’m hoping the winds die down enough so we can light candles at the Vigil on Monday night. It was nearly impossible last year.
I just had to stare really hard outside to make sure that the white flakes I saw flying by were not flower petals from the trees. Yep – just had a few renegade snow flurries fly by.
Yes, wdbrand – there is a fire in the woodstove for today.
Wow…for such a dry air mass I sure was surprised to see snowflakes falling (I did the same thing as Doppler Carol…staring intently to make sure it wasn’t a mirage) this morning out here at work – North County. It is rather dark over the mountains to the north of us.
Low of 40.2 in Goodview…and it’s only made it’s way to 40.6 so far.
Saw a few flakes here in south Roanoke County too, 500 feet above the Roanoke Valley floor.
Keep in mind all of our winter Arctic air masses are very dry too, but they can still have flurries squeezed out, too, in upslope NW wind flow.
Here’s a photo sent out by Snowshoe Mountain ski resort this morning.
http://blogs.roanoke.com/weatherjournal/files/2012/04/snowshoesnow.jpg
Thanks for the pic Kevin! That is why I love that place…and you’ve helped remind me I need to renew my season pass
Their golf course is great too…I’ll have to make sure to schedule a trip again this summer for that. Last year it was 85 on Friday on the course, then by Sunday it was in the 40s on the top o’ the mountain.
Kevin,
Looking long range when is the NRV’s next chance of any rain?
Middle of next week, a cold front pushes into the newly re-warmed and re-moistened atmosphere. There will probably be a pretty solid chance of showers and storms with that.
There may be a hint of showers Saturday with a warm front, but it looks really weak right now.
Total bust of a forecast high temp in Blacksburg today. The forecast was for 49, and it only reached 44, and that was at 12 midnight. The true afternoon high was only 41 today, no where near the 49 predicted. Did any local mets or the NWS project a high of 41 for the NRV today? This cold definitely way over performed the models. Also, saw snowflakes around 4pm today. You have to go back to April 7, 2009 to find an April day that was colder than this one. Looking forward to a very hard freeze tonight to put all this spring growth back in its place. Not ready to be mowing so much, so soon.
Roanoke failed to make 50 today, topping out at 49. First sub-50 high since March 5, only 3rd since Feb. 11. Even the day it snowed, Feb. 19, had a high of 52 (albeit, shortly after midnight, before falling to 33 most of the day).
Cloud cover was obviously underestimated by forecasts today. That’s why the daytime highs fell short. Some lows (like Roanoke’s 39 — not so much Blacksburg’s 32) were held up by the clouds last night, too.
Three to four feet of hail being reported in Texas:
http://www.connectamarillo.com/news/story.aspx?id=740934#.T4Ygh1HLyjN
I hope that’s a typo.
The video only shows flooding. But it wouldn’t be the first time there was 3 to 4 feet of hail somewhere in the High Plains.
Been on that highway (US 287) quite a few times myself. May be there again in about 5 weeks or so.
Hey, Weather Journal bloggers, want to see something interesting? Here is the link to the NAO outlooks page generated by GFS: http://www.cpc.ncep.noaa.gov/productsprecip/CWlink/pna/nao_index_mrf.shtml Please look at the top graph, “500mb Z (Obs: 14Dec2011 – 11Apr2012) NAO Index ” Graph shows the actual observed values of the NAO since mid-December.
Now please look at what happened between April 1 and April 5th and 6th (and 7th, to a lesser degree) on the graph. Big (well, “big” for these past few months anyway) nosedive into negative territory. But it was not cold on the 5th-7th, or even on the 8th-10th. Reason? What Kevin mentioned a while back, that there is a delay between a sudden change in the NAO values and a significant temperature change here in SW Virginia. Well, it sure looks like that delay is about 5 days. Look at what has happened to the NAO for the last three days …. big rebound all the way back into positive readings. Temps throughout the Virginia and Carolinas on this coming Saturday-Tuesday?? Upper 70s and 80s.
My word how I love learning stuff about weather here from Kevin!!!!
I messed up the link again. Forgot to check through it carefully. http://www.cpc.ncep.noaa.gov/products/precip/CWlinkpna/nao_index_mrf.shtml
One more time. Be like Orange Juice, Dougie …… Concentrate!! http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml
No frost here at the Chapel this morning due to wind and cloud cover. We too were way short of 50 today and it was 43 when I got home. Skies are still partly cloudy but showing signs of clearing. Covered my lilacs and hostas last night and again tonight. My peonias, japenese maple, azaleas and other things are on their own. Too much to cover. Guess we are paying for the 80′s and those early sun tans.
Wow, it only reached 48?? Today was the February day that we didn’t get in February (at least very often).