Category: Forecast Models

Jan 05

Confidence Increasing On Leader-Follower Event; But Details Murky…

A look over model data from overnight suggests we need to focus on a “leader-follower” event for the upcoming weekend.

We’re confident the “leader” player is a rain maker for IN in the Thursday afternoon-Friday time frame (.40-.70 rainfall potential).

Source: Tropicaltidbits.com

Source: Tropicaltidbits.com

As we progress into the second half of the weekend, details get quite murky on the specifics with the secondary (follower) area of low pressure that develops along a pressing arctic front.

As we’ve been discussing, model solutions will vary within each respected model (GFS, Euro, GEM, etc.) in a run-to-run fashion.  Stack them up against one another, and we’ll likely continue to have as many different solutions as we do models that we’re looking at.  It’s a byproduct of a pattern transition and that crashing SOI (which is still crashing this morning, btw).  Case in point, note the various options below for Sunday.

The GFS takes a low from southern AL into the coastal plain of NC. Source: Tropicaltidbits.com

The GFS takes a low from southern AL into the coastal plain of NC. Source: Tropicaltidbits.com

The Canadian is a blend of the GFS and European as it tracks low pressure from eastern LA into the central Appalachians. Source: Tropicaltidbits.com

The Canadian is a blend of the GFS and European as it tracks low pressure from eastern LA into the central Appalachians. Source: Tropicaltidbits.com

The European is most aggressive in the west track as it takes low pressure from the MO bootheel into northern IN. Source: Tropicaltidbits.com

The European is most aggressive in the west track as it takes low pressure from the MO bootheel into northern IN. Source: Tropicaltidbits.com

Past experience with similar patterns certainly leads us to lean more towards the European/ Canadian solution over the GFS from this distance.  We know that models have their own biases though.  Time and time again the GFS bias is to rush things along a bit too much from this distance and become too progressive.  On the flip side, the European is notorious for dragging it’s heels a bit and, at times, can be too slow with bringing energy out of the west.  This in return impacts things downstream…

From this distance, we still can’t be too specific with snow/ precipitation prospects Sunday.  While confidence is increasing on at least some sort of snow to contend with, the significance of such isn’t possible to iron out at the moment.  Much fine tuning will be required.  Stay tuned.

Permanent link to this article: https://indywx.com/2016/01/05/confidence-increasing-on-leader-follower-event-but-details-murky/

Jan 04

Monday Evening Update: Significant Arctic Blast Coming…

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/2016/01/04/monday-evening-update-significant-arctic-blast-coming/

Jan 04

Significant Period Of Cold; What About Snow?

The first work week of the new year will feature us looking ahead to a significant period of cold around mid month.  Additionally, we’re still trying to figure out the snow situation.  While we’re not ready to pull the trigger on a southern stream event or high ratio clipper, it’s going to be tough to get out of this cold blast without some sort of snow.  Those details we’ll become clearer as time draws closer.

A word of caution to those who watch operational data and want to iron out specific solutions in the 7-10 day range, you may want to stop (or have the dramamine handy).  When the pattern is in states of major transition, model mayhem can ensue.  Add in a crashing SOI and model output will continue to offer up a variety of solutions from run-to-run.

Screen Shot 2016-01-04 at 7.04.50 AMWhile we’re still not confident on how things unfold from a precipitation perspective in the Sunday-Monday time frame, we’re much more confident on the coming cold.  What’s on the table is a day where we see lows around zero and highs in the lower teens.  (Lay snow down and those numbers will drop lower).

The GFS ensemble is FINALLY coming around to seeing the arctic plunge. Source: Weatherbell.com

The GFS ensemble is FINALLY coming around to seeing the arctic plunge. Source: Weatherbell.com

The European ensemble screams “trouble” with a leader-follower type scenario Sunday-Monday.  We know Friday’s storm system is a rain maker for our area, but does a secondary push of energy lead to renewed storm development cutting through the Ohio Valley early next week?  That’s what we’ll continue to monitor.

Saturday

Sunday

MondayWhat do we know: That a significant period of cold arrives in the 13th-14th time frame.  Depending on the snow situation, temperatures around zero can be expected for lows with highs in the lower teens.

Still trying to sort through the details:  A lot is going on with our weather pattern right now and models will continue to struggle with storm specifics.  Whether we see a southern stream system put us on the table for snow potential, or deal with fast-moving, high ration clipper systems remains unclear at the moment.  Stay tuned.

Permanent link to this article: https://indywx.com/2016/01/04/significant-period-of-cold-what-about-snow/

Jan 02

Overwhelming Evidence On Mid Month Cold…

The step-down cold pattern early January is ongoing, but we’ve been clear with our thinking of even colder air invading around mid month (Jan 10th-20th time period). We wanted to…

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/2016/01/02/overwhelming-evidence-on-mid-month-cold/

Jan 01

Storm Brewing, But Questions Abound…

In the transition period from the “step down” cold pattern that we’re in now and the more sustained cold that looms for the second half of the month, we’re going…

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/2016/01/01/storm-brewing-but-questions-abound/

Jan 01

Winter Delayed, Not Denied: Updated Canadian; MJO

We’ll talk later today about the upcoming winter storm threat next weekend. While nothing is set in stone at this juncture, the pattern is aligning in a fashion for the…

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/2016/01/01/winter-delayed-not-denied-updated-canadian-mjo/

Dec 30

Quiet, Cold Pattern Turns More Active Next Week…

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/2015/12/30/quiet-cold-pattern-turns-more-active-next-week/

Dec 29

A Word About What Lies Ahead…

No need for model data or fancy graphs with this post, but instead we just wanted to level set with you on where we think we’re heading as we rumble…

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/2015/12/29/a-word-about-what-lies-ahead/

Dec 29

Rambling Around; Only A Couple Days Left In 2015…

December has been a warm and wet month for the region. In fact, it’s been so warm, some have labeled this “October in December.”       Snow and ice cover…

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/2015/12/29/rambling-around-only-a-couple-days-left-in-2015/

Dec 28

Strong Winds; More Heavy Rain…

Screen Shot 2015-12-28 at 7.38.21 AMHighlights:

  • Strong winds and flood threat continues
  • Weak mid week system
  • Much colder to open the New Year

Strong Winds And Flood Threat Remains…What an active morning across central IN!  Northeast winds are already gusting around 40 MPH with periods of heavy rain this morning.  Across our northern tier of counties (mainly north of a line from LAF to KOK) freezing rain and sleet is the issue this morning with temperatures below freezing.

Periods of heavy rain will continue today, and we also note the threat of embedded thunder (damaging wind risk) this evening, bracketed between the hours of 6p-8p.

Image below is courtesy of Weatherbell.com

StrongWindsTemperatures will remain cold and raw through most of the day before we see a late day rally briefly into the lower to middle 50s.  It’ll be another day with a tight temperature gradient across the state, as northern IN will struggle to make it much above freezing, while southern IN approaches the upper 60s this evening.

Midnight highs Tuesday can be expected before temperatures crash.

We’ll then set our eyes towards a weak wave of low pressure that looks to deliver a light mixed bag of precipitation Wednesday morning.  The freezing line will run through the central part of IN and a mixture of light snow and light rain can be expected.  MUCH colder air flows into the state behind this system and sets the stage for a cold open to 2016.

Image below is courtesy of Weatherbell.com

WednesdayForecast models continue to show an expected pattern shift to all-out sustained cold and wintry conditions for mid and late winter.  Note the W NA ridging developing.  Additionally, blocking and a negative AO develop as mid January nears.  Think this is the year without a winter?  Better think again, my friends.

Image below is courtesy of Tropicaltidbits.com

MidJan2016

Permanent link to this article: https://indywx.com/2015/12/28/strong-winds-more-heavy-rain/

IndyWx.com