UPDATE 5:20 PM: Might Friday be Roanoke’s last 90-degree day of 2012? Weekend cold front brings autumnlike temperatures
UPDATE 5:20 PM: It won’t be Roanoke’s last 90-degree day of 2012 — the high made it only to 88. The last 90-degree day of this year was either last Saturday, Sept. 1, or will be a day in the future during a warm spell. I’m leaning to last Saturday, with the possibility of reinforcing Canadian air shots in the next couple of weeks. Typically, we don’t have 90-degree heat in late September or October unless there is a continuing or intermittent heat wave extending from August into September — but of course, it’s still possible. END UPDATE
Over the past 10 years, Sept. 10 has been the average date of the last 90-degree high temperature in Roanoke. During the past decade, it came as late as Oct. 9 in 2007 (10 days earlier than the record latest in 1938) and as early as Aug. 18 in 2009 (the last 90-degree day has been in July on 4 occasions since 1912). So we are definitely in the part of the calendar when it’s not highly speculative to suggest that an expected 90-degree day could be the season’s last. Friday might be that day, as summerlike high pressure builds over for a hot and very likely dry day, with highs in the 80s most places west of Roanoke and upper 80s to low 90s in the Roanoke Valley and points south and east. It’s possible that last Saturday was the last 90 of 2012, or that there will be a later one, even this Saturday if the cold front is later arriving than forecast. But I think Friday has a pretty good chance of being that day, the 30th 90-degree day of 2012 — actually a tiny bit below the 100-year average of 33 90-degree days. Keep in mind we didn’t have our first one until June 19.
This weather map for Tuesday morning, posted by the Hydrometeorological Predition Center, shows that the cold front that will push through Southwest Virginia this weekend is a really big deal in the progression of summer into fall. By Tuesday morning, the front actually clears the Florida peninsula and pushes deep into the Gulf of Mexico, the first time we’ve seen that since May 11. The map also shows high pressure centered over Southwest Virginia — if that verifies reasonably well, and we get a clear night with calm winds, there could well be several 40s low temperatures in our region; certainly, widespread low to mid 50s are likely. After Saturday pushes into the 80s and storms develop ahead of the front, highs are expected to drop back into the 70s Sunday behind the front and remain there at least through midweek. This is a substantial shot of Canadian air that will clear out whatever’s left of Isaac’s tropical residue. It doesn’t appear likely to be a major rainmaker – cold fronts approaching from the west usually aren’t, unless there is a strong low riding up them from the southwest, and it may well be that the heaviest storms jump from west of the mountains to east of us in the Piedmont and coastal plain. But there will be some threat of strong to severe storms on Saturday, considering the strength of the front and the lingering warm, moist air in our region.
As of late Thursday night, it does not appear that Isaac’s offspring in the Gulf of Mexico is going to become a tropical cyclone — the storm is disorganized, with convection mainly southwest of the circulation center, and it has encountered both upper-level shear and dry air to keep it in check. Hurricanes Leslie and Michael continue to churn in the open Atlantic. The latest forecasts have Leslie veering a little east of Bermuda, and possibly scraping east of Newfoundland as well. That will still be close enough to create some higher surf and dangerous riptides along the East Coast — beware if you head that way the next few days.
September 6, 2012 - 10:47 PM
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I “vote” that some clouds come in to play tomorrow afternoon and keep temps below 90 at ROA, and that last Saturday (the 1st) was Roanoke’s final 90 degree day. Anyone else here in Big Lick care to “second” my nomination? How about you, Shanon? I bet S. Oakey would ….
How early do the.storms arrive on Saturday? I’m considering setting up at a local flea market, but I don’t want to be rained out.
Hopefully we’ll have a better fix on that by Friday night. As of tonight, GFS model doesn’t get much into our area til midday or early afternoon, while the NAM is 3-4 hours earlier. Neither of them really soak us — GFS even implies a Blue Ridge jumper with storms falling apart at mountains and redeveloping in Piedmont.
Ah! Been waiting for this fall weather! Finally!
But I’ll say that aside from June 28th-July 9th, this summer wasn’t too bad. It was bearable, and infact, really nice for most of June and August!
Foggy days count got around 23 for me in August! Snowy winter here we come! Haha!
Kev…
maybe with some luck..and just the right
moisture New Hampshire could offer the Snowbugs
some hope without going to Alaska..
Right there on the east coast.
Theyve been known to get 2 inches in Sept.
Looked at them during my evening shift,
WOXOF about all evening with temps right around 50f.
http://en.wikipedia.org/wiki/Mount_Washington_(New_Hampshire)
I will second that Doug. I was hot at the local football game last Friday night with just a t-shirt on. That did not feel quite right.
Well, last night I stated that it hadn’t been below 70 here since last weekend, and now it is 64 with starry skies and a moon directly overhead. This is more like it, at least for an “OH-dark-30″ morning in early September.
“7″ right now shows the rain holding off tomorrow until at least 1 or 2 PM here in ROA. And it definitely looked like a Blue Ridge jumper, at least here. It might hold together further SW. Great, just great. After tomorrow, sunny/mostly sunny skies right through most of next week in the outlook. Mother Nature just did a pretty good job of getting a lot of the lawns looking better here in this part of ROA County, and now it looks like the dryness returns.
I had a dream last night of standing on my back deck and watching it snow.
That put me in a great mood for the day, and knowing that we’re progressing into cooler weather just makes it even better.
BTW, the rain total from Monday-Thursday at my house? A pitiful 0.07″…thankfully we got over an inch during the weekend from two surprise, quick-hitting storms, otherwise I’d be buying out the green spray paint for my yard to make it look alive.
Storm Prediction Center slight-risk severe weather area for Saturday seems to be generally along the lines of a “Blue Ridge jumper” with slight risk along/east of the Blue Ridge.
http://www.spc.noaa.gov/products/outlook/day2otlk_0600.gif
Every time the map is updated the hole gets drier for us.
http://www.hpc.ncep.noaa.gov/qpf/p120i12.gif
A couple of things against you if you want rain / for you if you don’t want rain from Saturday’s cold front:
(1) Moving in from west, westerly downslope/vorticity shrinking over the mountains may dissolve showers/storms.
(2) Timing. Morning-midday arrival of instability band ahead of cold front means it doesn’t come through during peak heating, and overnight convection likely dies due to (1) and loss of heating.
I know a lot of eyes are going to be on the weather over Dublin, with the NRV Skyfest Air Show going on this weekend. If you bought tickets for that in advance they aren’t refundable….
I hope it doesn’t get to 90 today Doug! I’m best suited for 65-75 degree temps LOL. I’m looking forward to next week. Don’t get me wrong though….30 degrees with 6-10 inches of snow works well for me too
Right now, I don’t think the air show will be an end-to-end washout, but there might be a delay at some point for a passing storm.
Nurse Snow – loved your comment above – works for me too! LOL! Other John – nice dream you had!
Rick: Regarding your 10:13 a.m. comment about the HPC map, 12Z GFS model really bears out the relatively dry hole over SW Va.
http://tinyurl.com/cbvgxc7
The grass won’t like the blow hole settin up, but the lawn mower will.
Prediction for next week. 38 degrees somewhere in Greenbrier County. 40′s widespread Tuesday-Wednesday morning, with some spots in the Mountain Empire/NRV dropping to right around 40.
No 90 for Roanoke today. High of 88.
Yay, no 90* (yet) for Roanoke. Griggsy got that little wish granted. Please note that I hoped for it, that it was not a prediction. If I had actually predicted it would stay 89 or less, it prob’ly would have spiked to 92 or 93.
Amazing how much lower in the sky the sun is now. In late June and very early July, my backyard thermometer would remain in the sun until about 7 PM. It has been in the shade since a few minutes before 5:00, when my temp was 87.
Zach, where are you living now, if you don’t mind the personal question? Only reason I ask is that in that rainfall map that was a link in yesterday’s thread comment, Fancy Gap and the stretch of I-77 south of it down to the NC line were the rainfall winners, I think, for areas west of or within 20 miles of the Blue Ridge. That area got even more than the reincarnated Rain Hog, Michael Hoback. But I think parts of Henry County and other parts of Southside got even more than that swath of I-77.
NAM has the rain shadow too, not quite as pronounced.
http://tinyurl.com/d8wgggk
Doug I’m splitting time b/w Carroll County and Blacksburg. And I can personally testify from working in Blacksburg/Roanoke all summer. It rains not nearly as much here as it does in Carroll County. I don’t mean to exaggerate in any means, but the gap is very significant. Just this past week, we didn’t get hardly any rain in Blacksburg, while back home we had a couple of inches. I know the showers were spotty in nature, but it seems like our elevation/topography in Carroll County just helps more. It rained 13 out of the 17 days I was home this summer (Carroll Count, yes I counted haha). Alot of times this was not widespread rather just a pop up shower, but I have deffintly noticed how much harder it seems to get rain/storms in Blacksburg than it is in Carroll.
Zach, saw some snow throwers for sale at Lowes this evening…it’s getting closer!
I’m not surprised at all by your observations in Carroll County, Zach. Moist winds from the south hit a 3,000-5,800 foot wall of mountains in Carroll and Grayson counties. There is a fluke of geography near Fancy Gap where the mountains run east/west for several miles instead of the typical Appalachian southwest to northeast. Differential heating between mountaintops and surrounding lower elevations is always going to create boundaries there in summer. It should rain there first. Most summer days, it does.
Zach/Kevin…that topographical influence on rain can be seen in the map I’m linking from CoCoRaHS, from their state climate series…look at the nice bullseye near the Patrick/Carroll/Floyd confluence.
Meanwhile, my house…and it looks like maybe Wytheville Rick as well…are in the sub-38 category.
http://cocorahs.org/Media/images/composite-VA-1100w.png
Other John – but look at that map again – the yellow area which Floyd is a part of says 42 to 26 – hmmm – think that might be a typo?
I am amazed about a couple of things here today, by their absence. First, not a peep from anyone about the possible weather at tomorrow’s “big clash” in Blacksburg between 15th ranked VT Hokies and …. the Austin Peay “Governors.” Who??? I knew that A.P played in what used to be called Div. 1-AA, and in a state that touched the Mississippi River, but I had no idea about the details until I googled it. If VT were to blow that game, it would be an even more embarrassing loss than the one to JMU a few years ago. But it won’t happen.
Back to weather. According to Channel 13, game may start in some showers and I think he showed a kickoff (1:30 PM) temp around 77, then just cloudy by halftime at the latest and a lower temp of 74 (because of passage of cold front). I wonder if the 2nd half might be quite a bit windier.
The 2nd item? That Kevin has not posted when the most recent time was that ROA had high temps of 79* or less on at least 3 consecutive days, which might happen Sunday through Tuesday (or maybe even Wed. too?). Answer? June 14-18th, when that “boring,” really idyllic start to meteorological summer ended. There were two consec days once in July (12th-13th) and once in August (19th-20th).
More in a separate comment about “Hokieburg.”
NWS is not buying in on the “Blue Ridge Jumper” for Saturday, at least not yet, with rain chances at 70% in the NRV and 60% in Roanoke. Will be intersting to see if they back off in the morning. Most indications are that as KM already noted, it will indeed “jump” the mountains tomorrow leaving most folks in the NRV and RNK areas mostly dry.
For Blacksburg, I am going to increase the streak to 4 days. The most recent stretch when Bburg had 4 straight days with highs of 79 or less was not in August, but July!! July 10th – 13th. I bet Blacksburg goes at least 5 straight days with sub-80 highs starting on Sunday. Yes, I am predicting this one. Not a very brave call, however.
I see from Other John’s (Pulaski County Link-man) coco..etc link that all of SW Roanoke County is in the nice yellow area (42-46 inches annually). A couple of more summers like this one, and the area within 1 mile of my house might go orange. Same for the Leo Lady.
Hey, Rick, now I remember. you told me on at least one prior occasion that you live one mile west of Wythev. CC. That means you are one of the very unlucky ones on that rainfall map of a few days ago. But you knew that without needing a map to tell you.
May you get hit hard tomorrow.
Tomorrow is another one of those days in which I get rained on at my 24017 work zip code, and come home to a dry property. I am expecting the latter. If the entire first sentence of this paragraph happens, I will shrug it off. But it REALLY frustrated me big time last summer (2011).
Other John’s map shows an orange dot in the central VA surrounded by yellow. I think this is also where I see the climate zone show colder than surrounding areas. Why is this little part of central VA so different then the rest of central VA?
I omitted a word in the sentence that begins “Tomorrow is another …” Should be ” ….. one of those days in which I might get rained on at ….”
Kevin do we have any better idea of the timing the moisture arrives in the NRV tomorrow?
I bet someone catches my mistake immediately. I was looking at Bedford County, not Roanoke County. A colossal OOPS. Nearly all of SW County is in the orange colored area, meaning an average (at least for 1961-90) of between 38 and 42 inches. And there is an area of red (less than 38 inches) for the western edge of Roanoke County, that extends eastward very near or even to my subdivision.
I am stunned that one of the driest counties in all of Virginia is Pulaski County. That map really fooled me. I would have thought that the mountainous counties would be the wettest, when most of them are not.
Other John, go tell the CocoRaHS folks that they desperately need to update their rainfall map. lol How about 1981-2010??
Gotta remember that precipitation probabilites are based on .01 inch falling in the given time frame. GFS shows .01-.10 inch amounts. It could well be that the light amounts of the GFS verify AND the main storms jump the Blue Ridge AND the weather service is correct with its probability percentages. Or that there are a couple of heavier storms locally surrounded by dry areas, so that about 60-70 percent of the area season at least .01 inch (and a few get a lot more) while the remainder gets nothing measurable. The probabilities are not necessarily an indicator of intensity.
Arrival time for whatever occurs appears likely to be midday-early afternoon at this point. Here is the 18Z NAM simulated radar for 2 p.m. Saturday.
http://tinyurl.com/8uzhp3k
The air show at the Dublin airport, Olde Salem Days, and UVa and VT home football games are among the events affected on Saturday. Don’t foresee all-day rain, but perhaps an interruption near midday to let storms go by.
Local 18z WRF model run from Blacksburg NWS.
http://www.erh.noaa.gov/er/rnk/wrf/wrf_reflectivity_23.gif
Doug: Austin Peay has a football team my alma mater Arkansas State — which is often a rent-a-win for BCS-level football teams — would schedule as its rent-a-win back when our team was awful in the 1990s.
The local WRF model Ben posted is close to the NAM depiction, which is for a bit heavier rainfall than the GFS. This would be a pretty fast moving squall line, so there probably wouldn’t be a ton of rain for most folks if this verifies. Outdoor events would be temporarily halted — the games perhaps stopped briefly if there is lightning — then resume IF the NAM/WRF version transpires.
Rain shadow on HPC 2-day rainfall map;
http://www.hpc.ncep.noaa.gov/qpf/d12_fill.gif
I guess at this point I’m not sure this will be a total jumper — with total disintegration of the squall line to the west and then re-forming to in the Piedmont — but I do expect the highest threat of anything severe to be east of the Blue Ridge.
My Twitter feed blowing up with lots and lots and lots of wind damage reports in Arkansas with the severe squall line there. Wonder if the “D” word will be appropriate for what’s happening there.
Kevin, Have been watching the progress of those storms out of the midwest heading this way. So you think they don’t look like a total Blue Ridge Jumper, huh? Nephew who lives out in southwest Missouri – south of Springfield – said the trees in his back yard were just a swaying earlier in the evening with this line of storms. Lots of heavy wind.
KM, re: your 9:19 comment. Thanks for posting. However, everyone here should be advised that two blog folks are likely to get zippo, based on recent situation. The Mayors of Brownsville: of Roanoke, Leo Lady, and of the NRV, Ricko. Next likeliest: Shanon “Nurse Snow” and me. Honorable mention: Blacksburg Mike (or did you get a decent rain yesterday … I think I saw that the Bburg NWS got either 3 or 4/10ths).
Unless timing is much later than we think, I don’t see this being a widespread severe event for our region. Perhaps some localized strong winds. Orientation is wrong for heavy rain event, with storms lined up parallel to mountains moving east or southeast. Downpours would be quick. If you have outdoor plans tomorrow, just be prepared for taking a weather break for an hour or maybe 2 probably near the middle of the day. We’ll have to see if it speeds up or slows down any overnight.
One thing I really like about tomorrow’s possible rain here in ROA is the timing. I will just keep on delivering mail until it starts raining (unless it is only lonely raindrops). Then take my lunch break.
Back in the old days when I first started with USPS, occasionally we would get permission to deliver the route in a slightly different order than usual (that has been gonzo if one carrier is carrying the entire route for years). I have a high-rise (indoor delivery) near the beginning of the route tomorrow. Too bad I cannot deliver that during the rainstorm … if it happens.
NWS-Blacksburg forecast discussion, pretty much in line with what we’ve been discussing about tomorrow:
MODELS REMAIN A BIT UNCERTAIN IN HOW THINGS UNFOLD AND JUST HOW FAST CONVECTION SHIFTS ACROSS THE MOUNTAINS AND/OR REDEVELOPS OUT EAST. FOR NOW WILL GO A BIT FASTER INITIALLY…BRINGING IN POPS A BIT FASTER FAR WEST SAT MORNING…THEN HAVING COVERAGE WEAKEN UPON PUSHING OUT TOWARD THE BLUE RIDGE BY EARLY AFTERNOON. THEN EXPECT SHRA/TSRA TO CONGEAL BACK INTO A LINE ALONG/EAST OF THE MOUNTAINS DURING THE AFTERNOON AS SUPPORTED BY THE LATEST SPC AND LOCAL WRF SOLUTIONS.
Kevin, thanks for fully describing what the criteria were for the NWS chance of rain designation. I think it is very misleading. I hereby propose a new acronym in place of POP: CORR, for Chance Of Real Rain, meaning 1/10th of an inch or more. When a NWS forecast verifies because the vast majority of folks in an area got measly raindrops, but nobody or very few got even 0.10 inch, that is not “real rain.” IMHO …… lol
Goodness, major league bow-echo about to slam into Memphis. It’s already deposited an airport hangar into a highway in Arkansas. Wondering if this is Hurricane Elvis II for them (Hurricane Elvis 1 was July 2003 derecho event that paralyzed the city for several hot days).
I am going to try to link to something, and will be surprised if it works. NEXRAD radar for the chunk of the nation from the western halves of Missouri, ARK, and Iowa all the way to eastern VA and NC.
Here goes: http://www.wunderground.com/radar/mixedcomposite.asp?region=b4&size=2x
IT’S ALIVE!! The postal idiot actually did something right. To activate the map, go to lower left corner and click on: “Animate Map.”
Q: if today had reached 99* or so today, would that greatly increase the chance that the approaching front could be Derecho Part 2?
If it were arriving at 9 p.m., yes. Even the June 29 derecho started to run out of gas when it got to Virginia Beach at midnight.
Wow the radar looks pretty rough out to the west! Does all of that hold together into tomorrow?
Mr. Nottingham the area on the map in central Virginia is probably Nelson county. Since moving to central Virginia I have always said Nelson county looks out of place. The terrain looks like it belongs in the NRV or Mountain Empire.
That map is 1961-1990. I’m wondering how much 1 day — Aug. 19, 1969 — skewed the 30-year totals in that little dot in central Virginia. Nelson County got half to 2/3 a year worth of rain in a single night with Camille’s remnant depression. So the yearly total that year could have been very high. Probably not the whole reason that little dot is there, but it could be a factor.
Some of the instability numbers were extremely, extremely high to our west today. CAPE — Convective Available Potential Energy — is a scale used to measure instability. We would consider 1000 CAPE giving us a pretty good shot at severe weather. I’ve even seen 500 CAPE do the trick locally. 3000+ is pretty high-end for one of our Plains storm chase days. CAPE was 5500 in Northeast Arkansas this afternoon. Similar numbers were present on June 29 in some of the Ohio Valley and Mid-Atlantic.
Jared, the area of central Virginia that has the orange blob in it is mostly Fluvanna County, with pieces of northern Cumberland, NE Buckingham, and the western edge of Goochland County. Nelson County is to the SW of C-ville and has the greens and yellows in it. Again surprisingly to me, the eastern (lower elevation) of Nelson has the rainier green color. I have an ADC atlas of Virginia, and it shows the outline of the counties, and I matched them up. Carefully, this time.