Typical August Pattern

62 Comments

3:52PM

There is nothing unusual about the weather pattern we are in, nor will there be, in the next week or so. It’s August, there will be weak fronts trying to move through but having trouble. It will be warm and often humid. There will be spotty showers and thunderstorms from time to time. A little drying may take place for part of next week if we can get a northern jet stream trough deep enough and progressive enough to pull some cooler/drier air out of Canada.

As I hinted at on some recent posts, I thought that some of the medium range models were overdoing the cool/wet pattern, making the troughs in the jet stream too strong for too long, and that starting around mid month we’d see a western Atlantic ridge of high pressure a little stronger than the models were forecasting at that time. This is and will continue to be the case. We’re not talking about a giant ridge of high pressure and super hot/muggy weather for the East, but a ridge strong enough to prevent major pushes of cool/dry air from Canada, as fronts have trouble pushing through cleanly, and tend to weaken and fall apart nearby. This will mean that there will be some episodes of scattered showers and thunderstorms, which is typical of August.

The other concern with a pattern like this is the tropics. They have been tending to get more active lately, and recent medium range computer guidance has been showing a tropical system that may make an approach to the eastern USA by later next week. Now, realistically it is far too soon to really be concerned about any one particular place, but the consistency of a tropical showing up on many different computer models just tells us we should be on the alert in the days ahead. Once a system is formed and starts to move along, we can start the process of prognosticating where it will eventually end up…

In the mean time, the next few updates of this blog will focus on the weather for the Boston Area, eastern MA, nearby southern NH, and northern RI. Have a great day and a great week everybody!

Forecast Update…

FRIDAY: Partly sunny. Isolated to scattered showers and thunderstorms mainly during the afternoon, with the greatest chance being the further west and north of Boston you go. Humid. High 80-85. Wind SW 5-15 MPH with gusts to 20 MPH.

FRIDAY NIGHT: Variably cloudy with isolated showers and thunderstorms early, especially north and west of Boston, then partly cloudy. Patchy fog after midnight. Humid. Low 64-69. Wind light SW.

SATURDAY: Partly cloudy. Slight chance of isolated showers and thunderstorms again mainly north and west of Boston during the afternoon. High 81-86. Wind SW to W 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Low 65-70. Wind W 5-10 MPH.

SUNDAY: Partly cloudy. High 80-85. Wind variable 5-15 MPH.

MONDAY: Mostly cloudy. Scattered showers and thunderstorms. Low 68. High 82.

TUESDAY: Partly cloudy. Low 65. High 80.

WEDNESDAY: Mostly cloudy. Scattered showers and thunderstorms. Low 66. High 81.

THURSDAY: Partly sunny. Low 66. High 83.

62 thoughts on “Typical August Pattern”

  1. Just wrote this on previous blog, but will write it here too. There are astronomically high tides the last week of the month, if anything tropical hits any part of the US coastline at high tide, would not be much room to spare for a storm surge.

    Thanks for the update TK.

  2. Thanks TK. Great job as usual.

    We’ll have fun watching the tropics next week for sure. Something will get going or it won’t. We’ll know next week for sure.

  4. Scott,

    Don’t know what happened with my Euro earlier, But I do see this. This means
    that they are ALL on board, albeit with different solutions. The point being that
    the GFS, GEM and ECMWF all have this wave developing into a rather vigorous tropical system that certainly “appears” that it will threaten the US mainland.

    Time to begin watching carefully.

  5. Another small downpour pops up south of Boston. These seem to be short-lived showers. The one off Cape Ann is hanging on a bit longer, and on the 4:34PM panel of the NWS radar, it resembles a colorful pair of sunglasses, or a bug maybe.

  6. Thoughts on models… Euro: Not terrible, but may be too far south with the eventual track of tropical activity due to overforecasting the subtropical ridge’s southwestern extent. 06z GFS: Horrendous run. Throw it out or print it out for use in paper training your puppy, or lining the cage of your hamster. It has no idea about timing of jet stream systems, and is way over-forecasting the strength and amplitude of the jet. 12z GFS: This run has a decent idea on the overall pattern and, I believe, timing of systems. However, both of these GFS runs are too excited about shower and storm development on Saturday, in my opinion. The 12z NAM should be followed for the short term. Moisture as well as lift triggers will be largely absent on Saturday, and most activity should be tied up with a weak hybrid or tropical ESE of New England and an upstream trough over the Hudson Bay/western Great Lakes region. It is this trough that will probably result in a better chance of showers and storms in New England by Monday.

  7. I’m laughing at comments between looking like a bug and using paper for dogs and tears

    You are all great about answering questions and have always encouraged them. Its just me who feels as if I never stop asking :). Thanks to everyone and TK as always thank you for the update

  8. I would take that GFS run in about 5 months and run with it. The 12Z euro sure looks ominous but as TK pointed out probably a little off but it does look powerful.

  9. After reading previous comments regarding hurricane Donna in 1960, I am now realizing that we have a number of “old-timers” on these blogs. It’s no wonder that there is so much civility here compared to the WBZ blog. I was just born in 1960, so if you do the math, I need to focus on getting a colonoscopy at some point (groan). My parents and grandparents had always mentioned over the years about the devastating N.E. hurricanes of the 1950’s. During my time it was relatively peaceful other than Gloria (1985) and Bob (1991).

    Old Salty and Vicki…thanks for your stories about Donna! 🙂

    1. Philip you gave me a nice smile. I am a grandma two times with a third due in march. My 4 year old grandson has the weather bug. He pulls a chair for me and a tiny chair for him up to the window as soon as he hears booms (thunder). And he and I can always be found playing in the rain and snow. I guess the weather keeps you young!!

  10. I’m sitting outside on my back stairway and watching lightning from the severe storm 40 miles west of me… It’s awesome.

    1. Well that storm has lost its updraft and is raining itself out northeast of Fitchburg MA. Won’t even make 495.

      In the mean time, was just looking at the 18z GFS’s “Gulficane”. Not sure I buy a scenario that far south right now.

  11. I and it seems others here as well have no memories of hurricane Hanna back in 2008 so I had to do some research. Hanna existed from Sept. 4-7 which was actually well after the Labor Day weekend. Labor Day that year was on Sept.1st. From what I read the mid-Atlantic up to Long Island was the most affected. There were 7 deaths in the U.S. and 529 deaths in Haiti. I don’t know what effect Hanna had on N.E. but from what I can tell, it must couldn’t have been much if any. Maybe we only got just some typical 1-3 inch rains?? I really doubt we got any real wind given the track was over so much land long before it arrived here.

    TK, you seem to have a good memory of even past minor wx events. Can you fill in the blanks on this? If future “Harvey” or “Irene” follows a similar path, we can be better prepared. Thanks in advance. 🙂

    If Henry Margusity ends up being correct, my respect for him this upcoming winter is going to increase tenfold. Late last winter he did predict the devastating tornadoes.

    1. I remember Hanna and if I recall correctly, we did just get typical rain and some gusty wind on Sep 6 from the extratropical remains as they tracked across southeastern New England while accelerating toward the North Atlantic. Hanna was also notable for a cyclonic loop in its track southeast of the Bahamas and for the fact it was influenced by nearby Hurricane Gustav before its South Carolina landfall.

  12. According to the NHC there is actually something much more impressive just off the West Africa coast. It is already producing very heavy rains and strong winds in the Cape Verde Islands. The NHC at the moment is really bullish on this disturbance.

    Perhaps THIS is the one to watch for future development! We will see.

  13. I have to learn how to post some links……

    Anyhow, assuming I am looking at the most updated runs, the EURO has a hurricane over Cape Hatteras, NC in about 10 days and the 0Z GFS has one hitting Mississippi and then curving around a large Bermuda High providing rains to New England……

    I like to look at surface observations from all regions of the northern hemisphere. One thing I noticed this morning….since late June, most of the AM observations show 40s to low 50s up around the Arctic Circle. Well, subtle changes lately probably due to the longer periods of night at 65 to 75 degrees N latitude. Temps in the 30s are starting to show up again and a couple spots in northeast Alaska are down near 30 with clear skies and light winds. I suspect first frosts are starting to occur up there. Winter’s birth begins. 🙂

  14. Hmmm…

    The models are still onto something. The GFS takes it into the gulf and then
    hits Florida’s West Coast. Both The Euro and GEM bring it close to South Florida
    and then on up to Sc/NC.

    O6z GFS at 192 Hours
    http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_pcp_192l.gif

    0Z ECMWF at 192 Hours
    http://meteocentre.com/models/explorateur.php?lang=en&map=na&run=00&mod=ecmwf&stn=PNM&hh=192&comp=1&run2=00&mod2=ecmwf&stn2=PNM&hh2=000&fixhh=1

    0Z ECMWF at 240 hours
    http://meteocentre.com/models/explorateur.php?lang=en&map=na&run=00&mod=ecmwf&stn=PNM&hh=240&comp=1&run2=00&mod2=ecmwf&stn2=PNM&hh2=192&fixhh=1

    0Z GEM at 240 Hours
    http://meteocentre.com/models/explorateur.php?lang=en&map=na&run=00&mod=gemglb&stn=PNM&hh=240&comp=1&run2=00&mod2=gemglb&stn2=PNM&hh2=228&fixhh=1

  15. Philip, get the colonoscopy. Yeah, yeah I know it’s the most barbaric procedure left in medicine, but worth it still. (By the way make sure your insurance covers it — they’re costing $5K these days.)

    As for the tropics, a couple of these Cape Verde lows look stronger than anything else that’s come off Africa so far this season. Obviously to early to tell about the track, but I vote for fish storms. As for the ships in the lanes, this is all I can think of.
    http://www.youtube.com/watch?v=ykjZqIayMuo

    (Actually I believe this ship, at the time, was in the Drake Passage.)

  16. It is still a long ways out. Of the above, the GEM clearly has this one as a stronger
    system and has it in the best/worst position for a trek up the coast to New England.

    Watching…..

  17. Although there is still some summer weather left before the real fall and winter weather set in – I saw a commercial (don’t remember exactly what it was about) that showed someone driving in a snowstorm. And, I thought – Gee, that snow looks nice! 🙂 I guess I am looking forward to the winter and I don’t even realize it! 🙂

    Also, I am enjoying the discussions and models on this blog – interesting and intriguing.

    Vicki – I will probably be on at some point today or this evening, but I have a lot of errands and will be out a good portion of the day. So, if I don’t get a chance – Have a great vacation!

    1. Thanks rainshine. I will be here during vacation. I’ll have my phone with me and I may be able to give up politics (and dearly look forward to doing so) on vacation but not weather!!!

      My husband’s birthday is today and we are taking him to J J McKays – they should give you a discount next time you go 🙂

  19. Thunderstorm Index at a 1 for today so I don’t think will see severe weather.
    The tropics are heating up with a tropical depression that could become Harvey and affect Central America and two other waves with a medium chance of developing. The first wave the models want to bring it west northwest. This will be one for the U.S. to keep an eye on.
    Old Salty that is impressive 965 mb system.

  20. Just read the discussion from the NWS and Sunday things could get interesting with the cold front coming through. There appears to be ingredients there for strong to possibly severe storms and if the front comes through during the peak heating of the day and enough destablization can occur than watch out. Storm Prediction Center has us in the general risk area for thunderstorms and it will be interesting to see if we are upgraded to a slight risk as we get closer to Sunday.

  21. JJ,
    Is the sun angle considered in the heating discussion? It is getting lower and lower
    in the SKY. I just wonder what effect it would have? We may get storms, but I wonder if sun angle is too low to make for severe storms?

    I have noticed that our more severe storms come from Late May to Early August.
    After early August, they just don’t seem to happen.

    Just my thoughts and something to think about.

    Your thoughts?

    Many thanks

  22. Old Salty I would think the sun angle is considered in the heating discussion and I remember hearing a few years ago the sun is pretty strong into the month of October. To me if you have good dynamics at work you could get severe weather. In Windsor Locks, CT October 1979 that was not a particulary warm day but there were good dynamics at work that produced an F4 tornado. The direction that tornado moved to me was unusual moving to the northeast.

  23. JJ,

    I understand about the dynamics, but in all of the NWS discussions and the SSPC discusssions, they are always talking about day time heating to destabilize the atmosphere.

    To me, after early August, the only way to get severe storms is what you say, super dynamics in the atmosphere.

    Anywho, we shall see come Sunday. I’d wager no severe.

  24. JJ,

    Interesting discussion from NWS for SUNDAY: Here is an excerpt:

    DEPENDING ON HOW MUCH SURFACE
    HEATING OCCURS BEFORE CLOUD SHIELD ARRIVES SUNDAY POTENTIAL FOR
    STRONG TO DAMAGING STORMS POSSIBLE GIVEN STRONG WIND FIELDS ALOFT.
    APPEARS AS A HIGH SHEAR/LOW CAPE ENVIRONMENT SO KEY FOR
    STRONG/SEVERE TSTMS WILL BE DEGREE OF SURFACE HEATING.

    It would appear that NWS thinks that sun angle is AMPLE to provide sufficient heating.

    But still, I don’t recall much severe weather after about 8/9 or 8/10 or so.

    BTW, myself and family for that matter basically feel that summer is over around or about 8/10.

    Lol

    Have a great day.

  26. Will see what happens on Sunday because just like that tropical wave in the middle of the Atlantic it is worth keeping an eye on. To me summer is over the day after Labor Day because to me you don’t really get big long stretches of heat and humidity.

    1. Labor Day is considered the “unofficial” end to summer, but to me the chances of any remote hints of summer end with Columbus Day. After that we are definitely talking leaf raking, early morning chills, jackets, etc. September can still have its own “feel” of summer, so to speak at times.

  27. JJ,

    Yup, we’re all different and see things differently sometimes, which is great! What a dull world it would be if we all saw things exactly the same way.

    Btw, this latest tropical wave that the NWS has given a 40% chance of developing into a tropical system in the next 48 hours, is really being picked up my ALL of the models.

    This one sure needs to be watched, even for us, as some of the models place it in position to head up the coast.

    Still too early, but fun to watch anyway.

  28. Interesting wx tidbit….Boston’s record high temp yesterday Aug. 18 was 95 degrees which was set in (drum roll please)….2009! 🙂

    1. I just thought it was very ironic that a record high temp was set in one of the coolest summers, lol. 🙂

  30. So it seems the GFS has start to show a bit of consistency, that being a strengthening hurricane, no stronger than a cat 2, going up through the gulf and impacting those states along the gulf with at least tropical storm conditions and very heavy rainfall. Then travel northward and become a remnant low, eventually being taken over by the jet stream and headed our way with some rain.

  33. For example:

    Take the GFS plot above where the system has pressure of 992 MB.
    That would equate to about 120 km/hr or about 72 mph. Of course this is
    just an approximation to give us an “idea” of the expected strength of a system.

    Have a great after noon. btw there is some convection brewing..

    1. That would continue to strengthen as it gets closer to the U.S, possibly up to a cat 2, if that were to verify, which I don’t think will.

  35. Severe Thunderstorm Watch up for extreme western parts of SNE until 9pm and already some severe thunderstorm warnings popping.

  38. Scott, agreed that it is a long way out and what is depicted now for that time frame is not likely to verify. However, having said that, ALL of these models are onto to something here and now (still waiting for 12Z ECMWF) all pointing to a system in the Gulf. Things can change, of course.

    Interesting to watch it all unfold.

    2. I was on the beach near Duxbury Beach and it was so strange to see towering cumulus developing to our SOUTH. I could see the top of the clouds growing until it passed from the land to the ocean…then within 10 minutes of being over the water….poof and gone. Now, its clear with only clouds on the northwestern horizon, some cirrus at that, must be pretty good storms over central Mass.

  40. The 00z EURO had the system riding up the eastern seaboard, not sure if it was going OTS(out to sea) or headed straight for us.
    The 12z EURO will be interesting to see.

  43. Ok, the weather Gods are conspiring against me. I really apologize.

    Anyhow, it showed a vigorous system “Just” off of the NC coast, poised to head
    you know where.

  46. Severe Thunderstorm Warning:

    … A Severe Thunderstorm Warning remains in effect until 330 PM EDT
    for west central Norfolk… southeastern Worcester and south central
    Middlesex counties…

    At 240 PM EDT… National Weather Service Doppler radar continued to
    indicate a severe thunderstorm capable of producing quarter size
    hail… and damaging winds in excess of 60 mph. This storm was
    located near Milford… moving northeast at 20 mph.

    Amateur radio operators reported large branches downed in Hopedale
    at 240 PM.

    Other locations in the warning include but are not limited to
    Medway… Hopkinton… Holliston… Millis and Medfield.

    Precautionary/preparedness actions…

    This is a dangerous storm. If you are in its path… prepare
    immediately for damaging winds… destructive hail… and deadly cloud
    to ground lightning. People outside should move to a shelter…
    preferably inside a strong building but away from windows

  48. I’m not surprised that the models are predicting this disturbance to develop…..I was just on the NHC site and it looks like the upper level winds are ventilating this system well and when I peeked at the visible loop, it sure looks like there’s a weak, but broad circulation at the surface in looking at the movement of the low clouds.

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