Category: SST Discussion

Thoughts Shifting To Fall And Winter…

We may only be in mid August, but the IndyWx.com office is busy putting together initial thoughts around fall and winter (it’ll be here before you know it)! The upcoming…

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August Outlook

Before we dive into what we expect for the month of August, here’s a look at where we stand so far for July (with 4 days left as of this post).

This was our July forecast upper air pattern, issued 6.29:

July2015UAHere’s a look at temperature anomalies through 7.27:

ncep_cfsr_noram_t2m_anomWhile overnight lows have been running warm with all of the clouds and moisture, daytime highs have been significantly below average:

tmax30dydevWith four days left in the month, it’s already been the wettest month on record at IND.  The Corn Belt, as a whole, has been quite wet month-to-date.

nws_precip_conus2_mtd nws_precip_indy_mtd precip30dydevAs we progress into August (where does time go) we think we continue in an active pattern, locally, biased cooler than normal and wetter than normal.

AugustUA2015While modeling disagrees with the specifics in regards to the timing, most mid to long range modeling does agree on the overall idea of the hot dome (ridge) backing west and setting up shop over the southwest portion of the country early August which will put our region in (you guessed it) the favorable northwest flow for active weather.  Similar to July, disturbances will ride the periphery of the hot dome to our southwest and offer up plenty of chances for showers and thunderstorms.  That’s not to say we’re looking at setting another record for greatest amount of rain within a month, but it is saying precipitation should be above average yet again.

From time to time the ridge will attempt to expand northeast, but we don’t think it’s potentially until the last portion of the month before the ridge has much chance to encompass our region for any staying power more than a few days.  We suggest getting used to this 500mb look:

EarlyAugThe latest NAEFS and CFSv2 highlights the cooler than normal period we should undergo early August (especially after the 5th).

wk1.wk2_20150726.NAsfcT2015072712_054@007_E1_north@america_I_NAEFS@TEMPERATURE_anomaly@probability@combined@week2_186The latest European Weeklies suggest there may be a window for a “calmer” regime after the 25th.  That said, it’s a rather volatile pattern.

Yet another tool we’ve been keeping a close eye on the past few months has been the SOI (Southern Oscillation Index) as it’s been a big help in tipping us off for prolonged wet weather.  Note the consistent negative SOI:

Screen Shot 2015-07-27 at 11.22.11 PM

 

 

 

 

 

 

World

Not to sound like a broken record, but we continue to think the relentless wet weather pattern “keeps on keepin’ on” as we progress through August.  It’s very interesting to note the dynamics at play between the strengthening El Nino and warm northeast PAC waters… More on that, and the implications we feel for fall and winter, in the weeks and months ahead. 🙂

July2015SST

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July Outlook

With only a few days left of June, thoughts are turning to the 4th of July holiday, getting those summer vacations taken care of before school starts back, and pre season football practice starting up.

June will finish as one of the wettest on record, and coming on the heels of a very dry May, we’re actually right where we should be from a year-to-date precipitation perspective.

Here are some highlights we’re focusing in on that’ll impact our July weather:

  • Highly amplified MJO
  • Very wet June through the Mid West/ Ohio Valley
  • Warm water off the East Coast
  • Persistent western ridging

June will finish as a top 5-10 wettest June on record for many communities throughout our immediate region. With the wet conditions, it’s very tough to get any sort of long-lasting truly hot weather and while we’re certain to have plenty of warm, humid days during the upcoming four weeks (it is July, after all), we don’t anticipate any sort of significant heat wave. We fully expect being able to save on cooling costs when compared to normal.  We also note a highly amplified MJO, or Madden-Julian oscillation.

In July, phases 6-7 are cool signals for our region.

  
 We note sea surface temperatures are quite warm off the eastern seaboard and in the Gulf of Mexico. While this doesn’t have a direct impact on our weather here in regards to temperature, it can suggest some southeast and eastern ridging at times. When we look at the upper air pattern below, we note the region will likely be in between predominant ridge positions east and west for July. The end result for our particular part of the country would be a cooler and continued unsettled time of things for the better part of July.


*As a side note, this sort of water profile does “raise an eyebrow” for potential tropical activity in the Gulf and potentially along the east coast, and that’s something that we’ll have to keep a close eye on as we progress into the heart of the season.

We sort through a variety of data to help build our weekly (client based) and monthly upper air charts. While we can’t share all of those forecast models here directly with you (due to licensing), a combination of GFS ensemble data, CFSv2, and European weeklies have helped us build this upper air pattern for July.

July2015UAThis would provide continued cooler than normal times (particularly daytime highs, considering the wet ground) and a busy time tracking cold fronts and individual disturbances that will ignite frequent showers and thunderstorms.

“Average” July weather for IND includes mid 80s for highs, mid 60s for lows, and 4.5″ of rainfall.  In summary, we anticipate July 2015 to run 2-3 degrees below average and precipitation to run above normal by a couple inches.  We think we just keep on rolling down the tracks from the wet and active regime put into place in June.  Time will tell!

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Looking Closer At The Current SST Anomalies…

It may only be November, but we’ve been locked in the grips of Old Man Winter for the past few weeks (really since the early season snow back at Halloween).  While some “relaxation” will likely occur at a point during the first half of December, simply taking a look at the latest Sea Surface Temperature anomalies has to put a smile on the faces of those wanting cold and snowy weather for the upcoming winter.

waterprofile112114

Let’s take a look at the highlighted features above, starting in the Atlantic and moving towards the Pacific.

1.) Warm water off the eastern seaboard: Suggests some ridging is likely from time to time that could force would-be east coast storms inland.  This is a factor in our forecasted above normal snowfall for the winter of 2014-2015.

2.) Modoki El Nino: A Modoki event, or central-based, El Nino is far different than an east-based El Nino event and the associated “blow torch” that can ensue for the winter months.  Computer modeling continues to suggest a weak to borderline moderate Modoki event is in the cards.  The sensible weather here in the states is vastly different from this type of event than many of the broad-brushed El Nino impact maps you may see on various media outlets.  This is a cold, snowy look for many central and east.

3.) North-central PAC Waters: Water temperature profiles in the north-central PAC region continues to be an item we at IndyWx.com lean heavier on in looking at our longer range forecast outlooks.  The ring of warmth around the colder north-central anomalies in the Pacific suggests plenty of Alaskan ridging ahead in the coming months.  Downstream impacts?  Central and eastern troughiness and associated colder than normal air.

As we state, there are MANY drivers that impact the weather, and this is simply taking the SST anomalies (1 ingredient) and dissecting the impact that they alone would have on the region.  There are many other factors that we look at as we forecast long range weather.  Taken verbatim, the SST anomalies suggest we’re on the right track suggesting a colder, snowier than normal winter looms…  By the way, if you haven’t seen our winter outlook that was posted back on 10.19.14, you can view it here.

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