Capital Weather Gang - 2012 Summer Outlook

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http://www.washingtonpost.com/blogs/capital-weather-gang/post/washington-dc-summer-2012-weather-forecast-brutally-hot-again-dry/2012/05/02/gIQA03qWwT_blog.html

Quick Summary:

Temperatures

June: 2 to 3 degrees above average

July: Average

August: 1 to 2 degrees above average

Overall: 1 to 2 degrees above average

Number of 90-degree days for June/July/August: 40-45 (Normal is 31)

Number of 100-degree days: 1-2

Longest Streak of 90+: 9-12 days

Precipitation

Somewhat below normal (75-80% of normal)

Analogs: 1939, 1976, 1989, 2002

[easternsnowman]

http://www.washingto...3qWwT_blog.html

Quick Summary:

Temperatures

June: 2 to 3 degrees above average

July: Average

August: 1 to 2 degrees above average

Overall: 1 to 2 degrees above average

Number of 90-degree days for June/July/August: 40-45 (Normal is 31)

Number of 100-degree days: 1-2

Longest Streak of 90+: 9-12 days

Precipitation

Somewhat below normal (75-80% of normal)

Analogs: 1939, 1976, 1989, 2002

I'm thinking around dc this forecast is about right. My thinking is that further north will be average to slightly below.

[RIC_WX]

Imagine the interest if that was a winter forecast with the same analogs...

Thanks for sharing.

[The Dude]

Congrats on the front page of Metro placement! I read the first two lines, and immediately knew it was your work.

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Congrats on the front page of Metro placement! I read the first two lines, and immediately knew it was your work.

Ha. Thanks man.

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http://www.washingtonpost.com/todays_paper?dt=2012-05-03&bk=B&pg=1

[marked8]

It will be interesting to see how it does against Accuweathers forecast which is different:

"Temperatures will turn out near normal for the I-95 corridor from Boston to New York City and Philadelphia to Washington, D.C.," Pastelok said, since a lack of prolonged heat is expected this season.

Above-normal precipitation is forecast for the East during both June and August. The rain will be beneficial for communities that have endured a dry March and April and for some since the beginning of the winter. August may feature one or two big rain events, perhaps including a tropical system hit, that pushes rainfall totals over the norm.

http://www.accuweather.com/en/weather-news/accuweather-2012-summer-forecast/64673

Based on past history, Accuweather will be wrong.

[mitchnick]

It will be interesting to see how it does against Accuweathers forecast which is different:

http://www.accuweath...-forecast/64673

Based on past history, Accuweather will be wrong.

they seem to be riding the burgeoning NINO harder; CFS2 says they could be right "if" CFS2 is right

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbSSTe3Sea.html

otoh it seems hard to go with anything other than AN temps to some degree in DCA/BWI regardless of the NINO (unless it gets strong which I can't see happening)

so I'm rooting for Accuwx's temp forecast, but I think Matt's more likely to be right

[easternsnowman]

The way the trends are 1 or 2 above normal will seem cool to at best average.

[J.Mike]

The higher temps are OK. I'm concerned about the percipitation forecast.

[H2O]

I listened to Jason on DC101 last friday. Can't say that I'm happy with the warmer call but it fits the trend around here the last couple years. If it busts I want it to bust on precip.

[smokeybandit]

I want enough rain to keep my grass green and my basement dry

[DMADKAT]

Well borrowed days is the Grand General Weather God. For what I saw of the record, showed the odds favoring a cooler then normal summer and the cooler part in some years, reached 2.9 below normal opposed to only a little under 1 degree above in the others. Even warm winters combined with a heated March did not change things. Grand dad always said , ("borrowed days,,, too soon /used up.") Boy I sure hope he's right. It's been two beastly summers in a row here in Norfolk Virginia the last two years . The first one toasted us with back to back 105 degree days ( ALL TIME RECORD HIGHS ) and the second one last year, hit us with 102 and 103 in a row . Never in Norfolks history(SINCE 1871) have we had any back to back 102's or above in a row. It's really hard to get above 100 here for long . Too much water around.

[Bob Chill]

I haven't been paying a whole bunch of attention to the indices and analogs lately but it's hard to overlook the summer of 76 as being one of the best potential analogs for this summer. It would be quite risky to go cooler than normal across the board but if it did happen, it really wouldn't surprise me that much. Of course warm is prob the best bet.

There are some tasty analogs for the upcoming winter if we do get the Nino that is seeming more and more likely. IF we did end up with a moderate Nino, 57-58, 72-73, 76-77, 86-87, 02-03, and dare I say.....09-10 would all be in play. Not all of these were good winters but it does make for some good ENSO watching this summer.

[Deck Pic]

I haven't been paying a whole bunch of attention to the indices and analogs lately but it's hard to overlook the summer of 76 as being one of the best potential analogs for this summer. It would be quite risky to go cooler than normal across the board but if it did happen, it really wouldn't surprise me that much. Of course warm is prob the best bet.

There are some tasty analogs for the upcoming winter if we do get the Nino that is seeming more and more likely. IF we did end up with a moderate Nino, 57-58, 72-73, 76-77, 86-87, 02-03, and dare I say.....09-10 would all be in play. Not all of these were good winters but it does make for some good ENSO watching this summer.

It would stun me if we have a cooler than normal summer

[DMADKAT]

It would stun me if we have a cooler than normal summer

Really? Well it has been really cool here in Norfolk since that toasty Winter/March.. We will see. The weather always averages out in the long run. I've seen 50 years go by this Sunday(my birthday) and been avid weather watcher for 42 of those years and that is what I usually see. I hope for a break in these killer summers the past two years, for I don't get too much indoor plumbing work unless they can put a huge building inside a bigger building and then air condition it. That ain't happening, so I sweat it out.

[Deck Pic]

Really? Well it has been really cool here in Norfolk since that toasty Winter/March.. We will see. The weather always averages out in the long run. I've seen 50 years go by this Sunday(my birthday) and been avid weather watcher for 42 of those years and that is what I usually see. I hope for a break in these killer summers the past two years, for I don't get too much indoor plumbing work unless they can put a huge building inside a bigger building and then air condition it. That ain't happening, so I sweat it out.

ORF was +2.4 in April and is +3.0 so far in May

[Bob Chill]

It would stun me if we have a cooler than normal summer

Honestly, it would surprise me too. We've been on a heck on a + anom streak lately. However, I can't get past the possibilty of ENSO playing a role this summer. I pulled all the Nina's or neg-neutral years that transition into a Nino during the summer. There seems to be a correlation with a mean trough/ridge/trough setup in Jul-Aug over the conus.

June seems to run normal to warm during these transitions but Jul-Aug run a bit cooler than normal (a couple years were quite cool). SE ridge is generally non-existent.

Small list of years but 57, 72, 76, 86, and 02 all fit the profile (assuming we transition to a Nino trimonthly by the JJA timeframe).

Here's the mean 500 heights and surface temp anoms.

[Deck Pic]

Honestly, it would surprise me too. We've been on a heck on a + anom streak lately. However, I can't get past the possibilty of ENSO playing a role this summer. I pulled all the Nina's or neg-neutral years that transition into a Nino during the summer. There seems to be a correlation with a mean trough/ridge/trough setup in Jul-Aug over the conus.

June seems to run normal to warm during these transitions but Jul-Aug run a bit cooler than normal (a couple years were quite cool). SE ridge is generally non-existent.

Small list of years but 57, 72, 76, 86, and 02 all fit the profile (assuming we transition to a Nino trimonthly by the JJA timeframe).

Here's the mean 500 heights and surface temp anoms.

Good points....to counter, I am not sure those are all good analogs, but assuming they are, the sample is skewed by 1972 and by comparison to the new norms....2002 was of course hot and the other 3 were around normal versus the 1981-2010 norms (-0.5, -0.1, -0.3) and accounting for heat island and inflated mins, you can bump those up even more...especially 1957 and 1972....so we are really dealing with one well above, 3 slightly to somewhat above and one well below....Plus I think 1972 is the weakest analog of the bunch, especially considering Nino was well ahead of the pace we are on right now...we are neutral right now...though that will change

[Bob Chill]

I forgot to include 09 in my list but still, you're right about some of the others. Not really a strong argument for a cooler than norm summer. Just a highlighting the possiblity exists but odds stacked against.

I do like the mean 500 pattern though. With prevailing surface westerlies we could be warm to hot w/ compressional heating off the apps and br but it could potentially be less humid than normal this summer. I'll take that all day long. If a central us hp prevails over a bermuda high we be could be in for a comfortable summer even with +1-3.

[Deck Pic]

I forgot to include 09 in my list but still, you're right about some of the others. Not really a strong argument for a cooler than norm summer. Just a highlighting the possiblity exists but odds stacked against.

I do like the mean 500 pattern though. With prevailing surface westerlies we could be warm to hot w/ compressional heating off the apps and br but it could potentially be less humid than normal this summer. I'll take that all day long. If a central us hp prevails over a bermuda high we be could be in for a comfortable summer even with +1-3.

for the most part I agree....as we have seen for 8-9 months running now, I expect a +NAO in the means which has a reverse correlation (pushed a bit west) in the summer so a positive height anomaly over the Upper midwest and northeast and a negative height anomaly over the southern plains and western Dixie.....which means we get stuck in between regimes as usual, but should be in the heat sector more often than the cold sector

[Bob Chill]

for the most part I agree....as we have seen for 8-9 months running now, I expect a +NAO in the means which has a reverse correlation (pushed a bit west) in the summer so a positive height anomaly over the Upper midwest and northeast and a negative height anomaly over the southern plains and western Dixie.....which means we get stuck in between regimes as usual, but should be in the heat sector more often than the cold sector

Battle ground huh? Could help temps with more cloud cover than usual but the warm sector will be soupy. Heck, the cool side could be soupy if it has a NE surface flow.

I agree with the + heights over the upper mw. Good bit evidence pointing at that. Not sold on the NE though. Gotta wonder if the uber +NAO regime has burnt itself out. It's been flatlining for a while. The small set of analogs I picked were mixed during JJA. 2009 of course was major negative but there was something special about the mid 09- early 2011 timeframe with the NAO.

Best case scenario for a relatively comfortable summer would be have a nice + height anom centered over the mid - upper MW with normal to negative over the NE. It would be a dry setup but I'll take brown grass over sweating my eyeballs out anyday.

[DMADKAT]

ORF was +2.4 in April and is +3.0 so far in May

[DMADKAT]

ORF was +2.4 in April and is +3.0 so far in May

Are you sure? It seems to be cooler then I normally expect for this time of year. Lot of rain last few weeks and about a month ago it was near the 30's for lows.Maybe the night time lows are warmer then normal to raise the averages, or maybe March was so warm that May pales in comparison. 3 degrees is an awful lot of degrees above normal for so far in the month.

[ORH_wxman]

Are you sure? It seems to be cooler then I normally expect for this time of year. Lot of rain last few weeks and about a month ago it was near the 30's for lows.Maybe the night time lows are warmer then normal to raise the averages, or maybe March was so warm that May pales in comparison. 3 degrees is an awful lot of degrees above normal for so far in the month.

We've had a dearth of troughs on the east coast since basically October 2011. You won't notice the temp increase because its "normal" to have highs in the 80s without rain and coastal storms. But we havent had those for the most part. We had a period in late April and early May of that to a small extent, but overall its been benign weather with plenty of sunshine. When you get that, the temps will average above normal.

Troughiness and storminess is a big part of negative departures.

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We've had a dearth of troughs on the east coast since basically October 2011. You won't notice the temp increase because its "normal" to have highs in the 80s without rain and coastal storms. But we havent had those for the most part. We had a period in late April and early May of that to a small extent, but overall its been benign weather with plenty of sunshine. When you get that, the temps will average above normal.

Troughiness and storminess is a big part of negative departures.

Jason emailed me yesterday to discuss June and what effect it might have on the outlook and I told him it was troubling, but I wasnt too worried...A trough in early June hurts us especially because this is a time when SD is higher and we can put up some big + departures (like memorial day weekend), that can't be recovered from...It is much harder to put up consistent big departures in the last week of June here when our norms have skyrocketed to 88/70.....still, a week of -3 or -4 won't kill us...DCA barely radiates at night...we should have 71-74 mins here and there before too long....people forget that June 1-15 is not that warm here since it has been so hot the last 2 summers....you look back at an extreme example like 2003 when we had 14 maxes in the 60s and 70s and 16 mins below 65 and this seems insignificant

[Deck Pic]

Jason emailed me yesterday to discuss June and what effect it might have on the outlook and I told him it was troubling, but I wasnt too worried...A trough in early June hurts us especially because this is a time when SD is higher and we can put up some big + departures (like memorial day weekend), that can't be recovered from...It is much harder to put up consistent big departures in the last week of June here when our norms have skyrocketed to 88/70.....still, a week of -3 or -4 won't kill us...DCA barely radiates at night...we should have 71-74 mins here and there before too long....people forget that June 1-15 is not that warm here since it has been so hot the last 2 summers....you look back at an extreme example like 2003 when we had 14 maxes in the 60s and 70s and 16 mins below 65 and this seems insignificant

+5 today helps, especially if these -8's materialize later this week

winds shifted - +3

[Bob Chill]

+5 today helps, especially if these -8's materialize later this week

winds shifted - +3

Scanning through the last couple of runs of the gfs it looks like it's stuck on a decenent negative h5 anom around hudson bay. Euro kinda has it but the associated trough doesn't really push down past the lakes.

NAO has dropped to -2 sd's right now too. Obviously, not as significant as winter neg nao but it does support pushing an ec trough further south than we would usually see this time of year. NAO hasn't been in -2 territory in over 7 months so it's actually nice to see that it can still do it. lol

Prob more of a coicidence that anything else but current h5 config is pretty similar to my analog composite. We'll see what happens in jul-aug. Enso is continuing to warm so maybe we'll start to see some effect here down the road a couple of months. I wouldn't mind a normal to slightly below august one bit. Sweating my eyeballs out isn't really my thing.

[Deck Pic]

2002 is looking like a good analog...at least with placement of anomalies...we have another 10 days to see how the temp departures work out in the conus....here it was a +0.9 month based on today's norms....pretty unlikely we get there this months unless next week is a bust....1976 also has some merit...my other 2 analogs suck for june...at least so far

[Deck Pic]

Still a week left but June will end up cooler than all my analogs except maybe 1939 without the DCA/heat island adjustment of about +2 degrees that I use on older analogs. I did a slight adjustment on 1976 and a minor or no adjustment on 1989 and 2002. That just gives me a picture. I use other methodology. I don't just take the average and come up with my number. Some are weighted more than others. Persistence and conus pattern are important as well. We will finish quite close to 2002's 76.1. And there are other similarities too. Not a bad analog to have on your side.