Summer 2015 pattern discussion

[No snow for you]

Thanks east. I thought it would hit Japan and then turn north and then west but who knows.

[Eastatlwx]

Talk about rain shield, rainfall for the upstate of sc past 60-90 days, assuming some of you leave in the rain shield areas

[sparklecity]

Talk about rain shield, rainfall for the upstate of sc past 60-90 days, assuming some of you leave in the rain shield areas

 

My main takeaway from those maps is that you need to charge your phone   Well, and that we are in the beginning of a drought.

 

The GFS runs have been looking wet for the next 10 days.  0z has the upstate around 2" total.  Might just be GFS rain pron though.   CMC looks very wet too, but when hasn't it this summer.

[downeastnc]

Pattern next week should lend itself to lots more scattered storms and shower coverage in general in the SE as the high slips a bit more east off the coast giving us a more onshore flow so look for higher dews and more rain chances....then a weak front with possible low developing along it over the Carolinas as well....around next Thur-Fri and lingering through the weekend

 

http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=seus&pkg=mslp_pcpn_frzn&runtime=2015081612&fh=6&xpos=0&ypos=288

[Brick Tamland]

Looks like a chance of showers and storms in the forecast every day next week. If we actually get any is a different story.

[cbmclean]

Talk about rain shield, rainfall for the upstate of sc past 60-90 days, assuming some of you leave in the rain shield areas

Looking at the weather.gov precip history, I see that large areas of the atlantic souteast have been quite dry over the last 30 days (indeed over the last 90 days as well).  Is there a specific pattern anomaly which has caused this?  We've had some ridging in place at times, but nothing tat I would really call extreme, and large parts of the summer have been spent under mean troughiness.  Have we generally been cut off from the Gulf of Mexico?  If so, why?   

[Isopycnic]

Looking at the weather.gov precip history, I see that large areas of the atlantic souteast have been quite dry over the last 30 days (indeed over the last 90 days as well). Is there a specific pattern anomaly which has caused this? We've had some ridging in place at times, but nothing tat I would really call extreme, and large parts of the summer have been spent under mean troughiness. Have we generally been cut off from the Gulf of Mexico? If so, why?

The persistent northwest flow produces down sloping off of the mountains which aids in providing subsidence into the already weak flow over our region. Therefore the air is drier and storms aren't as prevalent.

[No snow for you]

Looking at typhoon number 2 it is going much further north and I hope it recurves

[cbmclean]

The persistent northwest flow produces down sloping off of the mountains which aids in providing subsidence into the already weak flow over our region. Therefore the air is drier and storms aren't as prevalent.

Thank you Isopycnic.  What has been the source of the persistent NW flow?  In a previous discussion on the topic, someone mentioned the Bermuda high.  Has it been absent or "out of position"?

[mackerel_sky]

Thank you Isopycnic. What has been the source of the persistent NW flow? In a previous discussion on the topic, someone mentioned the Bermuda high. Has it been absent or "out of position"?

It's been out of position and too far off the East coast. And there were big heat ridges centered over the gulf coast and that gave the plains states, especially TX and OK all the incredible rains in early summer and gave us the NW flow downsloping and extreme heat, downsloping is a warming and drying process. Another reason for the lower DPs than normal.

[cbmclean]

According to the NWS, at least our PWAT values will be much higher this week.

[superjames1992]

Looks like a good amount of rain tomorrow.

[Solak]

Looks like a good amount of rain tomorrow.

Compared to recent weeks, this would be a good amount -

"New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms."

[superjames1992]

Compared to recent weeks, this would be a good amount -

"New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms."

 

Looks like more here, and we've gotten a decent bit of rain in the last month compared to earlier this summer.  We are at a 4.67" of rain this month, which is over 2 1/2" above normal at this point in the month with at least another 1/2" (and probably more) on the way tomorrow, I would think.  We had almost 3" of rain on August 6th alone.  We're getting closer to erasing our deficit on the year.

[Solak]

Oh, I know.... we had a couple storms that started and died overhead this summer, each dropping over 1½". There's been very little general rain, and this area has seen the 'Carolina Split' more often than not. Maybe this week will mix things up, since we're finally going to have a SW flow instead of downsloping.

[Cold Rain]

Oh, I know.... we had a couple storms that started and died overhead this summer, each dropping over 1½". There's been very little general rain, and this area has seen the 'Carolina Split' more often than not. Maybe this week will mix things up, since we're finally going to have a SW flow instead of downsloping.

The west is favored. We'll get fringed.

[mackerel_sky]

The west is favored. We'll get fringed.

You enjoy the blooming onion, I'll enjoy the rain!

. The big wet is about to start!

[Cold Rain]

You enjoy the blooming onion, I'll enjoy the rain!

. The big wet is about to start!

You know it!

[sparklecity]

You enjoy the blooming onion, I'll enjoy the rain!

. The big wet is about to start!

 

Uh oh!  Not gonna be a happy camper if this verifies.  Big wets have a tendency to turn into Big fails for mby.

 

[NRVwxfan.]

Uh oh!  Not gonna be a happy camper if this verifies.  Big wets have a tendency to turn into Big fails for mby.

 

People sure love there clown maps. 

[Cold Rain]

^ That map accurately shows the areas with the best potential for the heaviest rains, even if the amounts show turn out to be inaccurate, IMO.

[NRVwxfan.]

^ That map accurately shows the areas with the best potential for the heaviest rains, even if the amounts show turn out to be inaccurate, IMO.

IMO, it shows way too many areas in SC and GA getting nothing..... And this is only one model out of many.

[Cold Rain]

IMO, it shows way too many areas in SC and GA getting nothing..... And this is only one model out of many.

Yeah absolutely...disregard amounts. The only way I view qpf maps is to look at the placement of the heaviest amounts in order to validate where the best chance of rain will occur. That and to heavily underweight my back yard.

[mackerel_sky]

Yeah absolutely...disregard amounts. The only way I view qpf maps is to look at the placement of the heaviest amounts in order to validate where the best chance of rain will occur. That and to heavily underweight my back yard.

Are you gonna get a meal and the all u can eat shrimp?

[sparklecity]

Looks like its already gonna be wrong just a couple hours into the run with that slug of precip moving into the upstate.

[mackerel_sky]

Looks like its already gonna be wrong just a couple hours into the run with that slug of precip moving into the upstate.

It's weakening as we speak! #DROUGHTBUSTERNOBUENO!

[sparklecity]

It's weakening as we speak! #DROUGHTBUSTERNOBUENO!

 

It's looking ok.  I'm hoping those deeper echos around Greenwood make their way up to sparklecity land.  If I can get under those I could prob pick up a half inch.  Otherwise this initial round will prob be less than a quarter inch.

[jshetley]

Timing doesn't look great for the drought areas although most of us should see some rain. As for tomorrow, I'm doubtful about much happening west of 77. East of there should do great tomorrow though.

[FoothillsNC]

Hi everyone. I was looking for a pattern change thread, but didn't see one, so mods move if necessary. But this does look to be a huge pattern change from the northwest flow we've seen since late April. I'm not totally sure, but I think my region just had its 100 driest days on record, or very close...atleast a top 5 consecutive 100 days (late April til August 1).  Between the 3" of rain fall, and non stop heat, another top 5 Hottest Summer if you include May, that really roasted my plants and trees. I see dead trees everywhere in the distance now here, and new ones show up daily, so this has been one wicked hot and dry summer locally thanks to a persistent nw flow and downslope. What a difference though just miles away, usually Upstate SC joins me on this, but not so this time as I went to Spartanburg and noticed a huge difference along 85. The rivers here are also in the 5th percentile (or were before August hit--made a close run to the 2007, 2008 years, and approached 2002, 1986 droughts, but all of those were more intense and longer lasting cumulative effects, so the last two Wet Summers here made a difference. Anyway, enough local. I think it's going to rain a little bit.

 

A southwest flow comes in from a weakness in the Lower Miss. Valley, and for once, a true southwest flow aloft has developed in the East and Southeast, which is the first this Summer. The ECMWF totally missed this a few days ago, instead having a huge closed ridge over us in this Time frame, which will definitely not work out.  But that closed ridge might come back later this month, or September, I have no idea.  I do know that watching evolving and dying droughts has taught me how this tends to go, especially interesting how it goes with developing Nino's.  And the 2009, 2002 late Summer droughts ended pretty quickly around late August and actually got wet by Sept and October. I don't know if we've turned the tables yet or not.  The models right now are showing another blocking signal in the day 10 to 15, matching the recurring tendency lately for negative NAO.

 

The first few images are Euro height anomalies, the last two images are the day 10 and day 15 off GFS. You can see it has been showing a Scandinavian block roll toward Greenland and a new one in southern Alaska. (nice double block) but who knows if it gets this right. Another thing that might be something to watch this Winter is the development of the large surface highs. Last year and the one before we had a lot of large ARctic highs come down. Will this year make the third in a row? I usually like warm oceans leaning toward development of cold landmasses, like central Europe and central US, and any slight shift in longwaves makes that push east usually. In our case, last year I missed the SC, NC, GA region mostly because of how the postive NAO ruled, and the TN valley was the axis of long wave trough.  Also, Nino faded out quickly early on.

 

 

 

 

Before we get to any long range though, the models all show a good southwest flow aloft most of the week, with high PW air. This alone is good for rain chances, efficient rain makers. By the weekend, a new ridge may form a type of split flow in the East, and more nw flow for most but that splitting is still conducive to rains in VA, NC, SC and GA, FL I think for a little while longer, maybe severe then too with drier aloft and divergence (GFS).  Then we might see the longer term effects of the Nino settling in. I don't know how early it really shows up but like I said above, sometimes the subtle changes in August are when it has shown up before, without even being forecast. Only time will tell ( I suspect we get dry again in September, then turn much wetter) even with no tropical influence. Florida will likely stay wet though from east winds , when a ridge is located north providing east flow....so enjoy the sw flow now for the upper Southeast. 

 

 

 

NAO forecast to go negative (and if GFS verifies will be severely negative) by near early October.

 

 ( some Winter thoughts)

 

For the Winter and I know this isn't a Winter thread, this might tie in with the overall evolution of how we see a 82/83 ,  1986/87, 2002/03, 09/10 type Winter comes about, but I know every Winter is different. For my thinking, the evolution of 5h and flow patterns is pretty remarkablly similar to 86/87 especially, but I won't say we'll repeat that season. Its just that the hot and dry Summer flow flipped like a switch in western VA, NC, SC and ne GA where it turned extremely active and lower heights prevailed with a storm track nw Gulf to GA, SC coast, and damming ruled a lot with mid 30s and rain, and a few storms cold enough for snow, ice.  That's how I lean right now based on just the 5h pattern going into the Fall, and not counting any actual model 5H anomaly forecasts. By the way, I totally missed the last Winter 5H up north in Greenland, as they remained cold throughout, and even though we got cold, the trough axis was west of Apps usually, and a strong pos. NAO meant the cold followed after the storm,a perfect recipe for cold and wet west of the Apps with just a few big events (like north AL, TN, KY and VA) but not much in GA, SC, NC.  I suspect the trough axis to be further east , placing Apps squarely in above snow and ice, with both sides of Apps a second runner up. But who knows, since the PDO and other factors make this setup a lot different than most ninos. Even though most peak in Dec, Jan time frame (even the super strong 97/98), the waters look warmer throughout the Pacific, so besides just knowing the PDO , one crucial element later on this Winter will be whether there is a negative anomaly south of Alaska, or another positive one, like we've seen last two Winters.  I lean toward a redevelopment of the latter right now, but there's time for that to change, so watching SST anomalies in real time will be a key factor on whether cold gets dumped down, with 1040 + highs again, or not. And split flow is very common most Ninos.    There are two camps of thought this season. One is that a strong Nino means west to east flow, flooding most of the lower 48 with above normal air. The other is that a closed ridge develops  alot in Pac NW and west Canada (like last two season), and allows more troughing in East. The truth could be either, or in the middle, I don't know ....even if it were December, it would be a guess. Who saw the ridiculously snowy, cold Alaska a few years ago, or the non stop cold Greenland and Canada, Lakes, Northeast Last Winter?  I like longwaves to decide that, and for a lot of reasons think an Apps longwave axis is the most probable. That turns out to be my snowiest climo, and I could care less in this older age just preferring plenty of cool rains. For the mountains though if that track results like most Ninos, then n. Al, n GA and western Carolinas western VA, and Wva, east TN usually do quite well on the totals.....with a battle zone on temps sfc and aloft usually near 85 corridor RIC to AHN.    Another thing will be if neg NAO is common this Winter, or not. Last year it wasnt'. Lately it is.  A lot of models show that anomaly again near Baffin to Greenland. I have no idea, except to say that Split flow alone usually provides enough opportunites for the Upper South to get into overrunning snow or ice atleast a couple times, usually, and big events centered in southern Apps to MidAtlatic to east TN valley usually. Throw in any neg NAO at all, and its a suppressed track. And then like I mentioned , since we are in a unique setup on the PDO, ENSO right now, a strong block would really look interesting in the Deep South.  All things tallied and  tolled right now, and its very early,  its' an interesting dilemma. It may rage warm (98) or be the perfect blend of timing , or a blend. As always, weather long term is hard to do. Timing is everything. The Nino may fade out quickly, but most models keep it going til Spring , with a 90% chance of still moderate then. Usually, they have peaked in Dec/Jan. This one is stronger early on, except maybe the 97 event.  It's interesting just to compare anomalies over past Ninos for comparison's sake and peak times.  Since Nino history of the knowns, is pretty short and limited, who's to say the Euro isn't right in showing a super event?  It must have happened before, say over 100 years ago? That's nothing in time really. Short term memory rules for most. We may have a blockbuster winter down south with a strong blocking signal and plenty of cold coming south again, meeting up with Gulf lows---or not!  The cold may only drop into the Northeast, or just Alaska , or only Greenland, with a strong west to east flow down in the bulk of the country, meaning a warm, wet Winter (although a one hit wonder is still likely based on the shear number of events coming through). Enjoy the rain--both short and eventually long term. We should get a lot of cloudy, overcast days coming up with a lot of Southern stream systems at some point this Winter into Spring.   Last Winter was quite cloudy for a neutral Winter.

 

 

 

Current global satellite:  A classic, active Subtropical jet/Pineapple connection in the distance.....

 

 

 

 

 

 

[calculus1]

Fantastic write-up, Robert!  It's been a long while since we've had such a good read in this thread.  I had to sit down with a snack to wade through it all from beginning to end.  Thanks for dropping by and dropping some knowledge.