A Lot Of Weather To Talk About…

Mother Nature seems determined to put us weather forecasters to hard work as we get set to head into the Christmas season and welcome in 2014.  We’re tracking a major flood situation that will unfold across central Indiana over the upcoming weekend, followed by a reload of the cold and potentially a storm with a more wintry component as we get closer to the New Year.

First things first and that’s the significant flood threat in the short-term period.  Without trying to go into scare tactic mode, current model data would result in a downright dangerous flooding event for many low lying and flood prone areas this weekend.  Rainfall numbers are extremely impressive with this event and with a deep tropical connection, widespread 3-4″ totals are certainly likely, including some localized higher amounts.  Note the latest European chart, courtesy of the model suite off Weatherbell Analytics.  Needless to say, the Gulf of Mexico is officially “open for business” and will help contribute to excessive rainfall totals and, as stated above, potentially a dangerous flooding event this weekend across central Indiana.

ecmwf_uvz850_noram_16

Latest numbers averaged off a variety of computer models would place just under 4″ of rainfall down by noon Sunday, most of which falls between Friday and Sunday morning.  We note (2) waves of enhanced rainfall intensity set to impact the region.  As of now we’re targeting Saturday afternoon and again late Saturday night/ Sunday morning for extremely heavy rain, shown below.

ecmwf_slp_precip_mc_14ecmwf_slp_precip_mc_17

We still have time to watch the data and monitor the track of the storm.  It’s possible the “heaviest of the heavy” axis of rain shifts somewhat in the days ahead,  but it’s also important to note that even a light to moderate rain event combined with a frozen ground and a solid snow pack still in place will lead to flooding problems here across central Indiana.  The question of whether or not we’ll deal with flooding here this weekend shouldn’t be asked, but instead the question that remains is just how severe will the flooding be?  Stay tuned and if you live or work in a flood prone area, we would recommend preparing now for flooding.

Now, as we look ahead and focus on the Christmas to New Years period our thoughts will shift from a flood threat in the near term to one that’s more wintry.  We’ll turn dramatically colder Sunday afternoon behind the big rain storm and that will set the stage for a colder-than-average run up to Christmas. In fact, latest raw numbers off some forecast model guidance has some frigid readings ahead next week (upper single digits not ruled out for lows).

The upcoming 10 days off the European forecast model charts show an interesting scenario with the coming thaw, but the key word is brief.  Note days 6-10 are back into a colder-than-normal regime.

tavg_anom_ecmwf_conus_1

Additionally, we think we’ll have to deal with another storm prior to the New Year period and with the colder air back in place, there’s the threat we could have to contend with a wintry side to the next storm.  The details with storm number two will have to wait until we finish dealing with the first storm and associated serious flood threat it’s presenting.

Snow Talk And A Look Ahead Towards Christmas Week…

Latest data in house still suggests a plowable snow is ahead for most of central Indiana this weekend.  We think wintry precipitation expands northeast to encompass all of the region between 7pm-9pm Friday evening (southwest to northeast).  This wintry precipitation still appears to take the form of all snow for IND and points north, but we caution that south-central Indiana communities will have to deal with a mixed bag of precipitation, including sleet and perhaps some freezing rain along with the snow.  The primary snow zone will have no trouble seeing snow amounts of 4-5 inches, but for south-central Indiana neighborhoods, snowfall accumulations appear to be closer to 2 inches, with additional accumulations of sleet also possible.  Needless to say, we feel pretty good about our initial snowfall forecast posted last night in our 7-Day forecast video (always available to the right of these posts in the video player).  The limiting factor, in our opinion, of even higher snowfall totals will be due to the speed of the system.  We think this is primarily a quick 6-8 hour “thump and go” type snow storm followed by some lingering light snow/ snow showers and gusty winds Saturday PM.  The sunshine returns for Sunday along with another surge of bitterly cold air with highs in the 20s.

Friday night-Saturday Snow Storm Highlights:

  • Wintry precipitation arrives between 7p-9p Friday across central Indiana.
  • Primarily all snow from Indianapolis and points north
  • Mixed precipitation south of IND will include sleet and freezing rain
  • Snowfall accumulations of around 2″ south-central Indiana, increasing to 4-5″ amounts along and north of the I-70 corridor.
  • Accumulating snow tapers off late Saturday morning.

Our attention then turns to what may lie ahead Christmas week.  After the chance of some brief “relaxation” from the current bitterly cold pattern, we look to reload the cold with authority around Christmas week.  In fact, if latest data comes to fruition, the current cold would pale in comparison to what lies ahead.  Additionally, a rather significant storm system could precede the arctic blast.  It’s far too early to talk specifics on precipitation type or amounts, but don’t be surprised if a storm of “significance” is on the maps as we approach Christmas week…

The latest ensemble plot from the GFS and European (below) agree on first class cross-polar flow setting up shop, which will help refrigerate the Lower 48 with some seriously bitter air just in time for Christmas.  Stay tuned…

test8

Data Suggests Cold Pattern Keeps On Keepin’ On…

As we approach the all-important holiday travel season, I thought it would be nice to review what some of the data suggests in the long range sense.  While nothing is “set in stone” talking about weather 2-3 weeks out, we feel pretty confident in the overall idea of a colder than normal pattern and one that’s also potentially wintry- from a precipitation perspective.  The specifics with each storm will have to be handled as they come.

Let’s look at some of the data.  BTW, I want to give full credit to the awesome model suite that can be found at Weatherbell Analytics for some of these images.  Be sure to check them out at weather bell.com.

First, we’ll take a look at the Canadian ensembles, centered on the 8-16 day period.  Note the tongue of cold coming out of western Canada, extending southeast and encompassing the Ohio Valley region.  Folks, this is significant cold forecast off the Canadian ensembles as temperatures are suggested to average 5-7 degrees (C) below normal.

can_t2m_mean_conus_d8_16

 

 

 

 

 

 

The latest GFS ensembles also suggest widespread colder than normal temperatures over the upcoming couple weeks.  Similar to the Canadian (above), the GFS suggests temperatures average 5-7 degrees celsius below normal.

gefs_t2m_mean_noram_d0_16

 

 

 

 

 

 

Latest European ensemble data suggests a cold look as well, but one that also may feature a day or two above normal (over the next couple weeks). The latest ensemble control run highlights the threat of some bitterly cold arctic air plunging south towards the second week of December (posted below).  We’ll continue to monitor this in the days to come.

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Here’s a look at the latest CFSv2. While it’s in stark contrast to only a couple of weeks ago (in its December forecast), the model is now onboard with most other data in forecasting a colder than normal December for our region.

CFSv2.NaT2m.20131124.201312

 

 

 

 

 

 

It has to be pointed out that all of the cold data is forecast during a time where the three “major” teleconnections really aren’t in the most ideal spots for eastern cold.  Typically, cold lovers across the eastern United States want a negative AO and NAO with a positive PNA. The NAO and AO are forecast to be very “sporadic” over the course of the upcoming 7-10 days while the PNA is forecast to go back negative.  That said, the NAO has the biggest influence on our weather from January through March (we’ve covered this in posts in the archives).  The expansive early season snow and ice pack through western Canada is having it’s say with a couple of early season “brutal” cold shots here (it’s very rare to get this kind of cold so early in the season).  We’ll continue to monitor these teleconnections moving forward for any sort of a more defined signal that may begin to come to fruition.

Speaking of snow and ice cover; look at how much more territory across the Lower 48 is covered with snow and ice compared to this date (November 24th) last year.  Impressive, huh?

November 24, 2012 (11.8% covered in snow)

nsm_depth_2012112405_National

November 24, 2013 (37.8% covered in snow)

nsm_depth_2013112405_National

As we look closer at the near term, there’s a chance of some light snow moving in Monday evening (not a huge deal, but some light accumulations of a dusting to half an inch are possible).  Scattered snow showers will also blow into central Indiana Wednesday as a reinforcing shot of fresh arctic air blows in prior to Thanksgiving.

In the mid range, both the GFS and European ensembles (below) suggest an “intriguing” look for the first 10 days of December for the potential of a more widespread winter weather maker.  It’s far too early for details, but with arctic air being supplied into a pattern that looks to have a southern branch beginning to flex it’s muscle, we’ll have to remain on our toes as we go into December…  Here’s wishing you a very happy and healthy Thanksgiving, complete with safe travels!

Geopotential32at32500hPa_North32America_240gefs_z500anom_nh_65

Thoughts On Winter…

This is the first time since 2002 that I haven’t produced a winter outlook.  Part of the reason behind this is due to the fact that our recent move back from Cleveland, OH to Indianapolis has taken priority.  Moving is always a much bigger chore than you expect originally.  That said, the upcoming winter of 2013-2014 presents quite the challenge when trying to determine what particular player takes control for the “long haul.”  I can’t remember a time when so many variables were at play, presenting quite the headache in trying to determine which one will take the lead.  Ultimately, confidence is lower than normal for the winter forecast.  That said, “confidence” in something 3-4 months out is never considered high. 🙂

Here are just a few items I’m looking at for the upcoming winter:

1. Data is pointing towards a southeast ridge in play for the better part of the upcoming winter.

The strength and precise position of the ridge will go a long way in aiding our weather here in central Indiana.  Southeast ridging isn’t always a bad thing in the winter if you’re a cold and snow fan as storms can’t “escape” harmlessly to our south or east.  That said, should we deal with a strong southeast ridge then we’re looking at a warmer, rainier time of things here as opposed to cold and snowy…

2. Modeling suggesting Nino Region 3.4 warms slightly as we progress through the winter months.

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The implications here are interesting when we drill down to the “home front.”  The following data from similar conditions during December-February in Nino Region 3.4 correlate to a few years that will go down in Hoosier snow lovers dreams…

Courtesy: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
  • 1977-1978: 49.7″ of snow, 2nd snowiest winter on record; Nino Region 3.4: +0.8
  • 2002-2003: 46.9″ of snow, 4th snowiest winter on record; Nino Region 3.4: +1.2
  • 2009-2010: 32.2″ of snow, 10th snowiest winter on record; Nino Region 3.4: +1.6

3. NAO showing signs of going negative when it matters most?

Labeled as the new “NAO Model everyone is looking for” may, perhaps, be just that.  This formula has already proven to be incredibly accurate in the past.  This was developed by fellow midwestern, Al Marinaro (you can follow him on Twitter at @wxmidwest).  In the past I’ve been one to say it’s incredibly difficult to forecast the NAO beyond 2-3 weeks, but we look at water temperatures this time of year to try and get an idea of what may happen in the coming winter months ahead.  If Mr. Marinaro is on to something (and it appears that he is) that longstanding idea will all change.

Additionally, to the delight of many cold and snow lovers out there, Mr. Marinaro’s formula suggests we’re heading for a predominantly negative NAO this winter.

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4. The normally “highly variable” CFSv2 (Climate Forecast System) monthly run has remained consistent as of late in thinking the east is warmer than normal for meteorological winter.  

It’s amazing how often this model is shown when forecasting cold, but seemingly forgotten when it’s forecasting warmer than normal conditions.

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Cold Close To October; Watching Halloween Closely…

Right on cue, the well advertised cold pattern is settling in and looks to remain entrenched over the region to close October and open November. Note the eastern trough and…

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