Category: PNA

Monday Morning Weather Rambles…

September is still running much warmer than normal, despite the recent well below average regime. See the temperature anomalies over the past (7) days:    and the month-to-date:      …

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/monday-morning-weather-rambles-3/

Cooler Times Ahead By Mid Month?

Summer sure doesn’t appear to be letting go anytime soon as our recent 7-day outlook suggests, but there are indications that our unseasonably hot and humid regime may take a back seat to the refreshing taste of fall in about 10 days.  The big “tip of the cap” towards the cooler pattern?  The PNA, or Pacific North American pattern, shifting from negative to positive.  As shown below, both the European (top) and GFS (bottom) highlight the PNA shift to positive.

Screen Shot 2015-09-02 at 7.58.03 AMA positive PNA favors eastern troughiness and an associated cooler than normal regime over our neck of the woods.

PositivePNASure enough, models are trending towards a much cooler direction for week 2.

Screen Shot 2015-09-02 at 7.54.04 AM

Screen Shot 2015-09-02 at 7.53.54 AM

Screen Shot 2015-09-02 at 7.54.14 AMIt’ll be fun to watch things unfold.  For now, if you’re a fan of summer weather, be sure to enjoy the next week, or so, as things appear to be changing for the much cooler side of things around the 10th (give or take a day or two).

Permanent link to this article: https://indywx.com/cooler-times-ahead-by-mid-month/

A Word On The Longer Range; Steady As She Goes…

We wanted to touch briefly on the longer range weather pattern as we’ve been answering questions this weekend out there concerning what lies ahead. Ultimately, the good Lord above is the only one who knows tomorrow and this idea we have very well may be the wrong one. However; we still see a lot of winter in this weather pattern. The combination of below average snowfall to date, combined with milder air the past 24 hours has led some winter lovers into a panic. Despite the past 24 hours, let’s remember where we are for the month of January through the first half:

image

Now let’s compare this to the infamous January 2014:

image

So far, this January the cold is more widespread across the nation. Additionally, through the first half of January, IND is actually running colder than last January. Many remember the brutal cold following the major winter storm early last January. Let’s also remember that a few days after that snow and cold we were dealing with much milder air and rain- a bonafide January thaw.

That brings us back to the present and our current January thaw. Looking back through the record books indicate even the coldest Januarys on record have “thaws.” What’s perhaps more impressive is that the end of this year’s thaw appears to be seen really before it even begins.

There are so many different drivers trying to take the wheel this winter it, admittedly, makes for an incredibly challenging time of things forecasting. That said, should we see the “stars align” (negative AO, negative NAO, positive PNA) in the coming weeks, this is the type scenario that could carry winter deep into spring.

In the shorter term, as of now we see no reason to abandon the idea the cold reloads to close January and open February. It’s possible that some weather outlets lean heavily on particular model runs and base their mid to long range forecast accordingly. While we agree you have to supplement some of that data into your mid and long range forecast, this is the type pattern than can make for risky business putting all the eggs in one basket.  (We also suggest any outlets leaning solely on operational and ensemble output are in need for a serious dose of dramamine). Instead, we prefer a blend of the above with the foundation being a combination of a nearly ideal SST profile for wintry times continuing and big-hitter analogs. It must also be noted that we have to keep the current AO/ PNA state in the back of our mind.

Speaking of those teleconnections… The current AO and PNA leave a lot to be desired for winter lovers in the longer range:

image image

That said, it should be noted the first two weeks of January cold was in the face of teleconnections that screamed of a warm pattern and a MJO phase that was also mild.

Perhaps the bigger driver here is the surface temperature profile in the PAC and ATL. Also note the modoki El Niño.

IMG_2167.PNG

That warmer water sitting across the northeast Pacific Ocean promotes ridging into the PAC NW and AK.  In return the upper level winds tap available arctic air and send it southeast (see the first two weeks of January).

In the mid range, ensemble data is bullish on this aforementioned pattern returning after the very brief January thaw.

1

2

The sensible weather that should result the upcoming 10-12 days?  An active pattern and one that’s very challenging with that northwest flow (we’ll be on clipper watch), biased colder than average.  In fact, the GFS ensembles aren’t too shy about eastern cold week 2.

gefs_t2m_mean_noram_d8_16

Let’s watch things unfold in the coming couple of weeks.  Make it a great day and GO COLTS!

Permanent link to this article: https://indywx.com/a-word-on-the-longer-range-steady-as-she-goes/

Brrrrr…. Cold Pattern Continues

Many across the Lower 48 are running MUCH colder than average this morning. Take a look a temperature departures from normal this morning: Mind you this is in the face…

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/brrrrr-cold-pattern-continues/

Shame, Shame, Shame; Humble Pie Never Tastes Good…

Shame, shame, shame…That’s all I can say when we deal with a blown opportunity for snow with a surface low that tracks in an ideal position for the white stuff,…

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/shame-shame-shame-humble-pie-never-tastes-good/