UPDATE 1:50 PM: Heat wave meets stormy end after today’s extreme heat; showery, much cooler days ahead
UPDATE 5:25 PM: Roanoke’s high hit 102 today, breaking another daily record, topping the 101 from July 8, 1977. Storms continue to develop along a cold front pushing into West Virginia and Kentucky. Storms in the Charleston-Huntington W.Va. currently are likely to move across Southwest Virginia later, with damaging winds and heavy rain possible. It’s not a derecho, but more typical summer storm clusters, but there is potential for at least localized wind damage to trees and power lines. Keep an eye on Radar / Future Cast in the right margin of this blog, and on the National Weather Service-Blacksburg web site for the latest warnings. END UPDATE
UPDATE 1:50 PM: Severe thunderstorm watch issued until 10 p.m. for localities north of U.S. 460 corridor (Blacksburg-Roanoke-Lynchburg). Expect this to be expanded south later as storms fire along an advancing cold front cutting into this extremely hot air. Damaging winds are the main threat in severe storms this afternoon, along with some hail. END UPDATE
UPDATE 1:35 PM: Roanoke has already reached100 degrees early on this Sunday — with sunshine continuing, plus downsloping westerly to northwesterly winds and some compressional heating ahead of the coming cold front, we could easily see a high of 102-105 this afternoon. 105 is Roanoke’s all-time record high, set twice in the 1930s and again Aug. 21, 1983. A severe thunderstorm watch is expected soon in West Virginia — this will be what we keep our eyes on for later today as it moves southward ahead of the cold front. END UPDATE
Roanoke’s official high through 5 p.m Saturday was 102 degrees, the third triple-digit reading in the last 10 days, which is the hottest period of that length in the Star City, based on average high temperature, since July 12-21, 1977. With three 100-plus days, six 97-99 days and one other at 94 (last Monday), the June 28-July 7 period has had an average high of 98.7 degrees. The 1977 period listed above averaged 98.8, with five 100-plus days. A high of 93 Sunday would tie this 11-day heat wave with a July 12-22 period in ’77, and 94 would make this one a tenth of a degree hotter. The high is projected to be near 100 for Roanoke on Sunday. Roanoke averaged 99.5 degrees over 12 days in 1930, and this period will not exceed that. I will check to see if there were any similarly hot 11-plus day periods during some of the blistering hot early-mid 1950s summers.
The biggest reason it will not surpass 1930 is that Sunday is very likely the last day of the ongoing heat wave, and maybe the last 90-plus day for a week or more. A major weather pattern change is developing that will rearrange the weather features that have led to so much extreme heat and mayhem east of the Rockies over the last 2 weeks. The jet stream is dipping southward into the Northeast U.S. — this will push a cold front southward that will collide with our heat, leading to a potential for severe storms Sunday afternoon evening just about anywhere in Virginia, and then only a little farther south on Monday. As is typical for midsummer cold fronts, it is expected to get hung up near or just south of us through the first half of next week, and that will provide a focusing mechanism for shower and storm development. Passing low-pressure waves along the front will have the potential to trigger repeated rounds of showers and storms the next several days as they lift Gulf of Mexico moisture over the stalled front. The Hydrometeorological Prediction Center is showing the potential of 2 inches or more of rain through Thursday over about the southern half of Virginia. I’m a little leery about jumping on those totals for now, knowing how difficult it often is to pinpoint exactly where a front will stall. The potential is certainly there for that kind of rain, and in any event, showery, much cooler weather than we’ve seen appears to be in the offing through midweek. Highs on Monday may have some chance of clipping a sticky 90 from Roanoke south and east, but by Wednesday may be struggling to make 80.
July 7, 2012 - 9:00 PM
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I’ll take it and hope for a bit of sun in there so my granddaughter can get out and enjoy a real Virginia summer while she visits. Of course she’s only a toddler so she won’t care but her parents might!
Is the NWS Blacksburg ever going to get their current conditions reading fixed? It’s still reading 0 degrees as our current temp.
The Blacksburg automated temperature readout from VT Airport is an FAA instrument, not NWS. Seems to be the last one to be fixed out of a bunch of them that were not registering earlier this week. Hopefully will be soon.
It was 91 on my front porch at the Chapel today. The Church has been without power since Thursday but ours never went off. It came back on up the valley about 2:30 pm and that will make services more comfortable. How we all used to live without AC I do not know. It is either getting hotter or we are getting softer. Maybe a little of both. Even though it was hotter last Saturday, I sweat more today due to the humidity. If we can just get through tomorrow and not lose power, it will be a record for my place but then the cooler wetter weather will arrive.
Can’t wait! Thanks for all your wonderful detailed info! I love it!
Kevin, How do you pronounce derecho I’ve heard it several different ways. Its of Spanish origin right? Thanks
People I would consider knowledgeable in the Spanish language and/or meteorological terms have come up with about 4 different pronunciations.
(1) day-RAY-cho
(2) deh-RAY-cho
(3) duh-RAY-cho
(4) deh-WRETCH-o
I spelled out (1) in print a few days ago but used more like (2) on WVTF Saturday. I think they’re really the same, just a matter of what one’s ear hears when the first syllable is pronounced.
Michael Hoback – your comment above – my feelings exactly!! Things are looking parched around here.
SPC is highlighting the Delmarva area for biggest chance of high winds today. That is where the greater atmospheric shear is.
http://www.spc.noaa.gov/products/outlook/day1probotlk_1300_wind.gif
Roanoke is in line for a record warm low this morning, at 78, IF later storms or their downdrafts or the cold front itself don’t drop it lower this evening. Previous record was 75 in 1977, the hot July that compares closely to the heat wave we’ve been having.
Back home in Christiansburg, and I’d welcome the cool temperature. I know I almost got sick from the heat, even though I was in the pool a lot, and I also think I got dehydrated. As soon I downed at least two glasses of water, I felt a bit better. I really feel for the those who have to work in the heat. It is brutal on the body.
July 1977 i remenber well , driving back from vacation to bush gardens , richmond was 110 that afternoon, my car then had 2-55 air, (two windows down and 55 mph, awh, my younger days.
Where are we on our string of 90+ degree days? I know you posted something a bit back saying the record was around 17 I think.
Already 91 here in Woodlawn. Tired of watering things (including myself) everyday! Trying to study some scuba diving for our class we are teaching tomorrow night. What I wouldn’t give to be 100′ down in the tropics somewhere!!
Today is day 11 of 90+ at Roanoke (all 94+). Record is 22 straight from 1966. Second place is 17 from August 2007 and August 1959. This one will not make the top 10 longest 90+ streaks even if scratches out 90 on Monday.
We’re already 95 today in Roanoke, so this now appears to be the hottest 11-day heat wave based on average high temperature since 1930. Will double-check 1953 but I don’t think it’s going to be hotter for 11 straight days.
Kevin, I think you mentioned previously that after this cool down we may have another hot spell. Any indications for that being the case now? We also had some discussion about boring weather several weeks ago. I think a lot of people could use some boring weather about now. My half of the street has power, but the other half still did not as of last night. I was in SC in 89 when Hugo hit, and we went 9 days without power, so I can appreciate how miserable that is. But with hurricanes that kind of damage is expected. Probably not a good situation for the insurance industry to be in going into hurricane season.
Already 100 at Roanoke at 1 p.m. Earliest 100 during this heat wave.
SPC out with Mesoscale Discussin 1433 that affects VA
http://www.spc.noaa.gov/products/md/md1433.html
Here’s the text:
MESOSCALE DISCUSSION 1433
NWS STORM PREDICTION CENTER NORMAN OK
1147 AM CDT SUN JUL 08 2012
AREAS AFFECTED…FAR ERN WV…CNTRL/NRN VA…MUCH OF MD/DE
CONCERNING…SEVERE POTENTIAL…WATCH LIKELY
VALID 081647Z – 081815Z
PROBABILITY OF WATCH ISSUANCE…80 PERCENT
SUMMARY…THUNDERSTORMS ARE FORECAST TO DEVELOP AND INCREASE IN
COVERAGE THIS AFTERNOON ACROSS FAR ERN WV INTO CNTRL/NRN VA AND MUCH
OF MD/DE. THIS ACTIVITY WILL POSE A THREAT FOR DAMAGING WIND GUSTS
AND LARGE HAIL. WW WILL LIKELY BE NEEDED.
DISCUSSION…MID-DAY MESOANALYSIS SHOWS A COLD FRONT SAGGING SWD
ACROSS FAR SRN PA…WHILE S OF THE FRONT…CLEAR SKIES HAVE ALLOWED
TEMPERATURES TO QUICKLY WARM INTO 90S TO AROUND 100F. THE HOT
SURFACE AIRMASS HAS AIDED IN STRONG BOUNDARY LAYER
DESTABILIZATION…WHILE EML PLUME EMANATING OUT OF THE WRN
CONUS…COMBINED WITH SURFACE DEWPOINTS IN THE MID 60S TO LOW
70S…IS CONTRIBUTING TO SBCAPE VALUES AOA 2000 J/KG. AS A
RESULT…AN ISOLATED THUNDERSTORM HAS RECENTLY DEVELOPED ALONG THE
FRONT OVER FAR S-CNTRL PA…WHILE CUMULUS FIELD OBSERVED IN VIS
IMAGERY IS DEEPENING OVER ERN WV/NRN VA. EXPECT THAT BOTH THE FRONT
AND CUMULUS FIELD WILL BE FAVORED AREAS FOR ADDITIONAL STORM
DEVELOPMENT DURING THE NEXT FEW HRS. THOUGH THE REGION RESIDES S OF
STRONGER MIDLEVEL WLYS…DEEP-LAYER WLY FLOW ACROSS THE WARM SECTOR
WILL YIELD 20-30 KT 0-6 KM BULK SHEAR…WHICH WILL BE SUFFICIENT FOR
STRONG/SVR MULTICELL CLUSTERS AND LINE SEGMENTS GIVEN THE
HOT/UNSTABLE AIRMASS. THESE STORMS WILL POSE A THREAT FOR DAMAGING
WINDS AND LARGE HAIL…AND A WW WILL LIKELY BE NEEDED FOR PART OF
THE MCD AREA.
..GARNER/WEISS.. 07/08/2012
Trevar, what the models are showing now isn’t a return to this kind of heat. They are showing high pressure building across the northern tier of the nation late next week and the following week. That would block any really cool air from Canada coming south, but not being under the core of it, it probably would not lead to 100-degree kinda stuff. We may be flpping the swtich from an extreme heat kind of summer pattern to more of a tropical moisture/sticky 80s/low 90s kind of pattern. High to the north of us like that would circulate in quite a bit of juicy air off the Atlantic and/or Gulf depending on where it was positioned.
Just posted a link to that mesoscale discussion in my 1:35 p.m. blog update, Quagmire.
It’s Official WW481 Severe Thunderstorm Watch til 10:00 PM for parts of VA mainly north of I-64:
http://www.spc.noaa.gov/products/watch/
Here’s a better SPC link for the Severe Thunderstorm Watch:
http://www.spc.noaa.gov/products/watch/ww0481.html
The 12Z GFS model goes bonkers with rainfall in SW Virginia north of the stalled front this week. This is the 5-day total through Friday on this morning’s GFS — 5+ inch blob across the region.
http://tinyurl.com/cqnjl3p
That rain forecast is crazy! It would figure we would go from insanely dry conditions to practically a monsoon pattern. Do you see us actually getting that much Kevin? Hard to imagine right now.
We made it to 90 at the Chapel before a severe TS went by. Not much rain and we were just on the edge. Lots of thunder and ligthening and some wind on the front end. Now the sun is back out and we are waiting for the bigger storms this evening and tonight.
Roanoke’s high is 102 for second straight day, once again breaking the record high for the date, 101, set in 1977. Blacksburg hit 93, 3 degrees short of a record dating to 1988.
I sure hope the summer prediction contest is over…….June 30th, right? I don’t mind losing (I picked a date in late July), as long as we don’t get nearly this hot again yet in July or August………….and please, tell me I didn’t get beat by some 9 year-old again.
June 29 was 104 at Roanoke — same day as derecho. Too bad I didn’t include highest wind speed this summer in the contest too.
Haven’t had time to check the entries and see if anyone was close on date. There are usually some 100-plus picks on temps — usually a couple go for 109 or something like that. I never see anybody pick 89 though.
Kevin,
What is the likelihood that this storm will hit the SW Roanoke County area? Should we stock up on ice? Thanks!
The chance of seeing some storms is pretty good everywhere. But this is NOT a derecho repeat. Wind damage will tend to be more spotty and localized. There will probably be some new power outages, but likely not on the scale of June 29.
Kevin,
Here’s a quote from the forecast discussion at 6:53
“OVER THE LAST COUPLE OF HOURS…STORMS EASTWARD MOVEMENT IN THE OHIO VALLEY SLOWING DOWN. THIS MAY BE ASIGN THAT THE FRONT WILL BE JUMPING TO THE LEE TROUGH IN THE EAST. THEIR IS STILL A CHANCE THAT EVERYONE WILL HAVE RAIN THIS EVENING.”
Translate that into English for me.
Crazy storm coming at us in Woodlawn from the north east!! Never seen that before!!
Mark: You can actually see this happening on radar. The storms in West Virginia have weakened dramatically, while the storms north and east of Roanoke have intensified. The “lee trough” refers to the weak area of low pressure that often forms on the east side of the mountains. Effectively, the cold front is sort of washing out where it has been and re-forming east of the Blue Ridge. Happens quite often.
Temp went from 86 to 67 in less than 10 mins and got .55 inch rain.
where clarkdocvet
We got up to 105 today before a line of storms knocked the heat wave square on the jaw and I think its finally down for the count. Temperature is in the low 80s now and the air feels like its trying to dry out somewhat.
Are we going to get any of this rain? It looks like it is falling apart and drying up before it gets here!
I think we’ll get some of the rain overnight – maybe some locally heavy rain. Front is sluggish, lots of heavier rain to the west, slowly moving our way. And if we miss this, there’ll be about 5 more chances this week.