August 2013 Pattern & Discussion

[LithiaWx]

Euro weeklies continue to advertise the pattern we have seen all summer, wetter and cooler than normal.

Long-Range Forecast Model Update Not Big on Any Major Warmup

July 30, 2013; 12:12 AM

The most recent update of the long-range ECMWF model, which was released Monday night still shows more cooler and wetter anomalies, especially for central and eastern regions through most of August.

The model just does not want to break down the northern latitude blocking, which in turn forces the jet stream farther south compared to normal, leading to a cooler/wetter pattern for many.

The exception is northwestern Canada, where a strong ridge of high pressure is expected to persist and Newfoundland, which is more due to the well-above normal sea surface temperatures in the North Atlantic which will likely remain through at least fall and probably the winter.

I personally think that the blocking will break down by mid-August leading to a warmer pattern than what the ECMWF is showing for central and eastern Canada.

ECMWF showing lower-than-normal tropical cyclone activity for August from the Gulf through the Caribbean basin.....

One more thing, the model is fairly consistent in forecasting a drier pattern in the Gulf and Caribbean through a good chunk of August and this is likely due to the presence of increased wind shear due to the suppressed westerlies and higher than normal sea surface pressures. To no surprise, the model is predicting only 40 to 60 percent of normal tropical storm activity in this region for most of August.

By the way, water temperatures in the basin are fairly close to normal, but we have been seeing above-normal wind shear and dry air/dust over the past couple of weeks, which are certainly inhibiting any serious development. Keep in mind though, it is still July and the tropics usually wait until the second week of August before things really start to get active. Hopefully, the ECMWF is right and it stays quiet through August.

Brett Anderson's blog on accuweather.

http://www.accuweather.com/en/weather-blogs/anderson/long-range-forecast-model-update-not-big-on-warming/15927728

[metalicwx366]

Looks like August will come in with average to slightly below average temps and wetter than normal. If you don't like the rain, move to Waycross. This month doesn't look as wet as June or July unless a tropical system comes into the picture. The CFSv2 says colder than normal for the majority of the Eastern US in August, but we learned how bad those those can be from last Winter. The GFS Ensembles indicate a incoherent MJO signal for the next two week so the tropics probably won't come alive until the middle to latter part of the month when we enter phase 8, 1, or 2. Of course there is always a chance for some homegrown development. Dry air and shear seems to be dominating most of the Atlantic and models don't indicate any development in the next 10 days. The remnants of Dorian look to enhance rain chances in Florida and potentially cause some flooding in areas. The SE continues to be drought free and looks to stay that way for quite a while.

[Cold Rain]

Both the 0Z and 6Z GFS show amazing amounts of rain over parts of the SE again. Basically, it rains continuously from about Day 8 on, with the occasional break here and there. Of course, take that grain with some salt, but it's pretty interesting to see nonetheless.

[Marion_NC_WX]

I've noticed both the GFS and Euro has been hinting at a full latitude ridge in the Day 7-10 range. With the blocking going on, it will be interesting to see what evolves downstream from that ridge...

[dsaur]

Looks like August will come in with average to slightly below average temps and wetter than normal. If you don't like the rain, move to Waycross. This month doesn't look as wet as June or July unless a tropical system comes into the picture. The CFSv2 says colder than normal for the majority of the Eastern US in August, but we learned how bad those those can be from last Winter. The GFS Ensembles indicate a incoherent MJO signal for the next two week so the tropics probably won't come alive until the middle to latter part of the month when we enter phase 8, 1, or 2. Of course there is always a chance for some homegrown development. Dry air and shear seems to be dominating most of the Atlantic and models don't indicate any development in the next 10 days. The remnants of Dorian look to enhance rain chances in Florida and potentially cause some flooding in areas. The SE continues to be drought free and looks to stay that way for quite a while.

The US Department of Inclement Weather says this year has been a banner year for rain for many...just not you!  Notice the pointillism on the above charts does not encompass your area.  Those of us without a swamp near by need more water   Sorry, MetalMan, but there it is.  You will see snow flurries this winter, so all is not lost.  See the Dept. of Inclement Weather snow flurry maps.......  T

[metalicwx366]

The US Department of Inclement Weather says this year has been a banner year for rain for many...just not you! Notice the pointillism on the above charts does not encompass your area. Those of us without a swamp near by need more water Sorry, MetalMan, but there it is. You will see snow flurries this winter, so all is not lost. See the Dept. of Inclement Weather snow flurry maps....... T

Lol! The maps say it all. Awesome snow flurries a second year in a row! Do you think they will accumulate more than the trace we saw this March? Last year you told me I would see snow and I did.

[dsaur]

Lol! The maps say it all. Awesome snow flurries a second year in a row! Do you think they will accumulate more than the trace we saw this March? Last year you told me I would see snow and I did.

I believe you will see up to .1 from flurries, and it's quite possible for you to see an inch this year, in Feb. probably after the 20th, most likely around the 30/31st.  The Moles are quite adamant about this, so what could go wrong?  Tony

[Met1985]

I've noticed both the GFS and Euro has been hinting at a full latitude ridge in the Day 7-10 range. With the blocking going on, it will be interesting to see what evolves downstream from that ridge...

Ya the blocking coming up looks strong for this time of the year and is a major player going through the month. It will be interesting.

[metalicwx366]

I can't wait T lol.

I hate this upcoming pattern. Didn't work out for us in July lol.

SUN THROUGH WED AN UNSETTLED PATTERN DEVELOPS AS MEAN LAYER TROUGHING AND HIGH MOISTURE CONTENT (PWATS OVER 2-2.25 INCHES) POSITION AND LINGER OVER THE REGION. EXPECT PREVAILING SW FLOW THROUGH THE PERIOD WHICH WILL BRING A DOMINATE WEST COAST SEA BREEZE REGIME. WILL CONTINUE TO CAP RAIN CHANCES FOR ALL AREAS AROUND 50%...BUT AS THE DAYS NEAR SUSPECT HIGHER RAIN CHANCES OF 6O-70% MAY BE NEEDED AS TIMING AND FEATURES BECOME BETTER RESOLVED.

[DCMetroWinston]

How in the world do we get better and more sustained blocking in July and August than we had last December and January?

[jburns]

I believe you will see up to .1 from flurries, 

 That's his seasonal average.

[WxJordan]

Here is the blog i wrote yesterday. My website is focused on NC weather, but it can be expanded in this case to the entire southeast. With the trough(s) continuing to move down and the stubborn ridges, wet weather will be expected over the SE USA. I believe many areas will see above average precipitation is the Southeast United States in August. Temperatures will also remain in check with the lower heights overhead. I am expecting average temperatures for many locations.

 

 

August appears to be wetter than normal and have near normal temperatures in the Carolinas.

The same weather pattern that has been causing numerous showers and storms through the months of June and July is expected to continue into August. This pattern has brought flooding rains and record rainfall to many areas of the southeast, including North Carolina. Many areas have already reached the total amount of rainfall they should receive in a year based on averages.

August appears to be similar to June and July.

A ridge of high pressure is expected to remain in the western United States and the Bermuda high is expected to stay well of the coast. This will allow the east coast trough to remain in place through the month of August. Showers and storms should continue in the area with the same threats: heavy rain, lightning, winds, and damaging hail.

While I do not believe we will see the amounts of rain we saw in July, I think the pattern does allow for fronts to continue to dive into the Carolinas and produce heavy rain showers and storms. Another important "feature" to watch will be the tropics. Any tropical storms or hurricanes that do develop may move towards the Southeast coast, which could cause major damage with the rains we have had and the winds. It is impossible to forecast tropical storms this far out, so we will have to wait and watch what happens in the tropics.

TO RECAP: I expect above average precipitation in August for many locations. I expect near normal temperatures for many locations in August.

 

http://www.wxjordan.com/weather/discussions/122-august-to-bring-above-average-precipitation-temperatures-around-normal

[Marion_NC_WX]

The Friday 12z GFS hasn't gone out into the medium/long range yet but going by recent runs, I think after this weekend we are going back into another active pattern where the low levels provide the moisture and the northwest flow aloft will lay the path for thunderstorm complexes to dominate. Areas like Mid/West TN, MS, AL, GA are the usual suspects. Maybe areas farther east like Eastern KY, Northeast TN, Southwest VA, So Apps get in on the action this time around.

[mackerel_sky]

Does anybody know how rare it would be for any cities here in the SE to have back to back months of double digit monthly total rainfall?

[Marion_NC_WX]

Better enjoy this relative calm in the weather dept, looking like our Bermuda High is getting ready to ramp up again just off the coast...very nice opening between the ridges placed right in the heart of the Southeast.

 

Wonder if we might have something sitting there trying to brew in the Eastern GOM next weekend?

 

 

[DCMetroWinston]

Average temps have started to decline in the Triad.

[Marion_NC_WX]

The juice returns to a lot of the Southeast next week...

 

Really high PWAT's,...

 

Surface to 850 mb flow in a south or southwest trajectory...

 

Favorable LI's and surface CAPE...

 

Leftover surface convergent boundaries...

 

 

 

All of that leading to an active week coming up. It will all begin to go downhill by Tuesday...and by mid to late week, a lot of players in place for rainfall to again pile up pretty quick.

 

 

 

 

Foothills put out an update for his online subscribers earlier tonight, he nailed last month pretty well and it fairly bullish for the next 2 weeks...

[buckeyefan1]

I'd like to see this wording in December   

 

 

CAE.....

 

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL BE SLOW TO PROGRESS THROUGH THE LONG TERM
AS A BLOCKING PATTERN REMAINS STRETCHED FROM AK THROUGH THE CANADIAN
PROVINCES. THIS WILL KEEP AN UPPER LEVEL LOW NEAR HUDSON BAY WITH
THE CORRESPONDING TROUGH OVER THE EASTERN US. UPPER RIDGE TO THE
SOUTH AND WEST TRIES TO BUILD TOWARD THE REGION LATE IN THE PERIOD
FRIDAY AND SATURDAY BUT WILL MEET A LOT OF RESISTANCE FROM THE
EASTERN CONUS TROUGH WHICH REMAINS FAIRLY STRONG. THIS WILL KEEP
AN ACTIVE WEATHER PATTERN OVER THE AREA AS A FRONTAL BOUNDARY
STALLS OVER THE REGION WEDNESDAY THROUGH THE END OF THE LONG TERM.
THIS WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE
FORECAST WITH INCREASING CHANCES DURING THE LATTER HALF OF THE
LONG TERM. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY
BELOW TO NEAR NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS NEAR
NORMAL.

[Cold Rain]

RAH seems relatively unimpressed with rain chances in the central and eastern Piedmont until late week into next weekend. Higher chances look confined to the western areas and up near the VA boarder.

[DCMetroWinston]

Just how long have we consistently had this eastern blocking and troughiness? March?

[Cold Rain]

Just how long have we consistently had this eastern blocking and troughiness? March?

 

Don't get used to it.  Winter's a comin'.

[DCMetroWinston]

Ha! Aint that the truth.

[Cold Rain]

Ha! Aint that the truth.

I fully expect to see another winter filled with predominately little blocking....we may have a tendency for a trough in the east, if soil moisture has anything to say about it, but that's just one component. It would be wise to keep a weather eye on the Pacific jet. As it goes, I'm afraid, so goes our winter...in a general sense, at least.

[LithiaWx]

New weeklies out with an interpretation by Brett Anderson of Accuweather.

[DCMetroWinston]

IF those weeklies are accurate, they take us to the last week of meteorological summer, the week before Labor Day and September.

[dsaur]

I fully expect to see another winter filled with predominately little blocking....we may have a tendency for a trough in the east, if soil moisture has anything to say about it, but that's just one component. It would be wise to keep a weather eye on the Pacific jet. As it goes, I'm afraid, so goes our winter...in a general sense, at least.

Someone needs some attitude adjustment, lol.  Think of the little children!!  Look at the speckles on the above maps, and remember winters don't come in threes   Ye of little faith.  Do we have drought....Noooo!!!  Do we have heat....noooo!!  Things change...now get off your butt and call us up a snow storm mister!!    T

[Cold Rain]

Someone needs some attitude adjustment, lol. Think of the little children!! Look at the speckles on the above maps, and remember winters don't come in threes Ye of little faith. Do we have drought....Noooo!!! Do we have heat....noooo!! Things change...now get off your butt and call us up a snow storm mister!! T

Well, admittedly, part of my negativity was attributable to the fact that at the moment of my typing, the wife had me watching some Gwyneth Paltrow movie that was NOT Iron Man. The other part is just going with persistence. It's a strong force. But like you said, some things are different, and it'll be interesting to see how/if that translates over into the winter. We'll have to see what the dr. orders in the snowstorm department later on.

[griteater]

Does anybody know how rare it would be for any cities here in the SE to have back to back months of double digit monthly total rainfall?

 

Here are the occurrences for GSP, AVL, and CLT

 

Greenville-Spartanburg, SC (data since 1884)

1898 (Jul-Aug)

 

Asheville, NC (data since 1869)

2005 (Jun-Jul)

 

Charlotte, NC (data since 1878)

1886 (May-Jun)

1928 (Aug-Sept)

 

July was the 2nd wettest month ever in the Asheville records, for any month (that's a total of 1,637 months in the records back to 1869...there is missing data for some months in the late 1800's).  Wettest month ever was August 1940.

 

http://www.erh.noaa.gov/gsp/climate/climatology/climatology.htm

[GaWx]

Does anybody know how rare it would be for any cities here in the SE to have back to back months of double digit monthly total rainfall?

 

 Since records started in 1879, Atlanta has had back to back months of double digit monthly total rainfall only once: Feb. and March of 1881 (10.41" and 10.98", respectively).

 

In 2013, June had 9.57" and July had 8.48"...so fairly close to doing it again those two months.

 

Atlanta's wettest month since 1879: July of 1994 with a whopping 17.71"! TS Alberto had a major impact that month (7-8") though 10" or so of that month's rain actually wasn't directly from Alberto! Four of the non-Alberto days had 1"+ of rainfall.

[mackerel_sky]

Since records started in 1879, Atlanta has had back to back months of double digit monthly total rainfall only once: Feb. and March of 1881 (10.41" and 10.98", respectively).

In 2013, June had 9.57" and July had 8.48"...so fairly close to doing it again those two months.

Atlanta's wettest month since 1879: July of 1994 with a whopping 17.71"! TS Alberto had a major impact that month (7-8") though 10" or so of that month's rain actually wasn't directly from Alberto! Four of the non-Alberto days had 1"+ of rainfall.

. Thank you for the information! I was curious, because if the August pattern keeps going with a wet theme, and some cities can reach double digit totals, we will be witnessing a pretty rare occurrence !