Category: Forecast Discussion

Arctic Blast Today; Big Winter Storm Brewing

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6/ 14

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Forecast Updated 02.27.14 @ 7:30a

Fresh Arctic Air…A fresh arctic air mass is blowing into the state this morning on gusty northerly winds. Top wind gusts here at IndyWx.com HQ, in southern Boone County, have been clocked at 41 MPH so far this morning.  Despite a lot of sun today, don’t look for the thermometer to move much. In fact, we forecast most communities to remain below the middle teens- a far cry from the average high of the middle 40s.

Watching A Light Snow Maker…Most of Friday will feature sunshine, but clouds will be on the increase during the afternoon and some light snow will follow late Friday night into Saturday morning. This won’t be a big deal and really looks unimpressive- less than an inch for most neighborhoods.

Big Winter Storm Brewing…We continue to gain confidence in a winter storm that will impact central Indiana Saturday night through Monday morning.  The set up is one that will feature an arctic front stalling out across the state Saturday night into early Sunday with moisture overrunning the cold air in place, resulting in periods of significant precipitation- mostly in the form of snow.  Finally, a wave of low pressure will move out of the Mississippi River Valley northeast into the Tennessee Valley Sunday night into early Monday.

Our initial snowfall idea places a band of heavy snow through the majority of central Indiana, including Indianapolis, to the tune of 6-8 inches.

Bitter Air Flows In Behind The Winter Storm…A bitterly cold air mass will plunge into the area behind our winter storm.  With a fresh, deep snow pack in place and clearing skies, it’s possible that we could be looking at below zero temperatures both Tuesday and Wednesday mornings.  Forget that the calendar will say early March by this point…

Upcoming 7-Day Precipitation Forecast

  • 7-Day Snowfall Forecast: 6-9″
  • 7-Day Rainfall Forecast: 0.00″

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Permanent link to this article: https://indywx.com/2014/02/27/1186/

Tracking A Late Weekend Winter Storm

Wed. Thr. Fri. Sat. Sun. Mon. Tue.               5/ 18 8/ 14 2/ 23 22/ 37 20/ 30 10/ 20 5/ 18  – –…

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Permanent link to this article: https://indywx.com/2014/02/25/tracking-a-late-weekend-winter-storm/

Looking Ahead; Cold Pattern Reloads.

We’ll have your updated 7-Day forecast posted later today.

The latest mid and long range guidance continues to suggest we’re heading into another prolonged period of below normal temperatures.

Ensemble data (below) shows ridging in the northeast Pacific, extending into Alaska and this pattern has been one of the big reasons as to why we’ve dealt with so many arctic intrusions this winter.  (The first image is a look at the upper air pattern dated Feb. 26th and the second is dated March 11th).

Ridging in this particular part of the globe often times dislodges the cold air and someone “down stream” has to deal with below normal air.  The recipient of being “down stream” has just so happened to be the upper Mid West into the Ohio Valley and much of the eastern half of the country this winter.  That doesn’t show any signs of changing over the next couple weeks, at least.  It’s possible we could deal with a day or two of milder weather thrown in the mix, but the overwhelming majority of the upcoming couple weeks looks much colder than normal.

GEFS1GEFS2

The result is a continuation of much below normal cold in our part of the country.  The following graphics illustrate temperature anomalies (in celsius) centered on 5 days between Feb. 23rd-28th and March 6th-11th.  Below normal temperatures continue.

GEFS3GEFS4

 

 

 

 

 

 

 

 

 

 

 

A couple of additional thoughts around the upcoming cold pattern: While we can’t show the images here (license issues), the “secret” European weeklies and ensemble data continues the cold, stormy regime across the east for the better part of the upcoming 30 days, with a couple of brief periods of milder, “calmer” weather.

Finally, the CFSv2 suggests the cold regime continues, as well.  The first image shows upcoming weeks 1 and 2 and the second shows temperature anomalies weeks 3 and 4.  Note the CFSv2 shows southeast ridging developing towards the end of the period, potentially suggesting a big fight goes on between the cold to the north and the budding spring conditions to the south- a stormy suggestion…

CFSv2Wk1:2CFSv2Wk3:4

In closing, it’s important to note that all of the fancy graphics shown above are simply model guidance and it’s up to us, the forecasters, to interpret the data the best way possible to put together the most accurate mid to long range ideas for you, the viewer.  While nothing is a guarantee in this business, it does appear as if chances are quite high that our region deals with another few weeks of colder than normal conditions and potentially active weather ahead.  Stay tuned.

Permanent link to this article: https://indywx.com/2014/02/23/looking-ahead-cold-pattern-reloads/

Back To Winter We Go

Fri. Sat. Sun. Mon. Tue. Wed. Thr.               31/ 43 31/ 44 26/ 34 18/ 32 19/ 26 8/ 22 7/ 19  Light –…

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Permanent link to this article: https://indywx.com/2014/02/20/back-to-winter-we-go/

Focus On Mid Week Flood/ Storm Threat…

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Accumulating snow?

Forecast Updated: 02.19.14 @ 8:00a

One More Calm Day…A weak front blew through early Wednesday and produced a light shower for southeast parts of the state.  Sunshine will return Wednesday along with a blustery northwest wind.  It’ll be another mild day.

Concern For Flooding And Severe…With continued melting of a deep snow pack, combined with around an inch of rain (most of which falls within a 3 hour time period Thursday) and the stage will certainly be set for flooding.  In fact, we remain very concerned for flooding Thursday. If you live in a flood prone area, please prepare to seek higher ground Thursday as flood waters rise.

The second concern is a severe potential Thursday evening.  While the greatest threat for severe weather will remain south and east of our immediate region, we’ll have to be mindful of the potential of damaging straight line wind gusts Thursday evening.  The greatest threat lies between 5PM and 8PM Thursday as a line of thunderstorms pushes east through the state.  Again, damaging straight line winds, in excess of 60 MPH, is our greatest concern at present time.  Stay tuned.  Drier and much colder air will roar in behind the front Thursday night on strong and gusty northwest winds.

Weak Weekend Disturbances…A couple of fast moving disturbances will pass through the region this weekend and could spark scattered snow showers in the much colder air.

Accumulating Snow Early Next Week…Model data continues to struggle in the mid range handling energy coming east before what continues to look like a big blast of arctic air to wrap up February.  As of now, we’re targeting Tuesday for best chances of accumulating snow, but stress this a low confidence forecast in regards to timing at present.  Stay tuned.

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Permanent link to this article: https://indywx.com/2014/02/18/focus-on-mid-week-flood-storm-threat/

Messy Afternoon Commute Ahead

Latest thinking around our wintry mess due in here this afternoon places a heavier emphasis on sleet and freezing rain for central Indiana, with accumulating snow still a possibility, especially north of Indianapolis.

Overnight model data trended warmer (especially aloft) and latest high resolution, short-term, data continues that trend this morning.  While an initial push of moisture has led to snow and sleet reports already this morning, it’s around 1 o’clock when we think the true slug of moisture reaches the city, itself.  While snow can’t completely be ruled out, I’m more concerned with sleet and freezing rain potential for Indianapolis.

Officially, we’re calling for 1″ of snow/ sleet with up to two tenths of freezing rain for the city, itself.  Further north, a band of 1-3″ of snow/ sleet can be expected with only light freezing rain.  From Benton County over to Wells County, we anticipate mostly a snow event with 3-6″ of snow expected.

All of that said, we leave you with this humble disclaimer; this is easily the most difficult forecast we’ve had to make this winter.  Several factors will come into play to ultimately determine the precise precipitation zones, including track and strength of the low, precipitation rates, amount of evaporative cooling, etc.  This is a low confidence forecast when it comes to precipitation types, but our best idea is below for your viewing pleasure.  Needless to say, regardless of what type of precipitation you see this afternoon, prepare for another nasty afternoon and evening commute.  Stay safe.

UPDATED021714

Permanent link to this article: https://indywx.com/2014/02/17/messy-afternoon-commute-ahead/

Early 0z Runs Trending More Icy Vs. Snowy…

Quick post tonight just to alert you that early model runs off the 0z suite of data suggests less of   a snow threat and more of freezing rain/ sleet…

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Permanent link to this article: https://indywx.com/2014/02/16/early-0z-runs-trending-more-icy-vs-snowy/

Sunday Afternoon Thoughts…

1.) A scan over the latest data continues to point towards an absolute mess of a Monday afternoon.  Our accumulation ideas remain relatively unchanged from this morning’s update, aside from “beefing” expected snow totals for Indy’s northern ‘burbs by 1″.  Most of this falls from noon to 6pm and will be followed by a dry, cold, and blustery Monday night.  After likely a white-nuckle evening commute Monday, the combination of sub-freezing temperatures and gusty northwest winds Monday night will likely lead to another rough commute for Tuesday morning.

** We caution that this will be another “now cast” situation when it comes to precipitation types and their respected precise zones tomorrow afternoon.  Stay tuned here or to your favorite local weather media for updates and potential changes.**

  • Indianapolis northern ‘burbs, including Zionsville: 2-4″ snow and sleet with less than 0.10 of freezing rain.
  • Indianapolis proper: 2″ snow and sleet with around 0.10 of freezing rain
  • Indianapolis southern ‘burbs, including Greenwood: 1″ snow and sleet with up to 0.25 freezing rain.

Snow:IceForecast021714

2.) We continue to monitor what will be a brief thaw and associated flood risk mid week.  Even without rain, water rise would occur and urban flooding from the combination of melting snow and blocked (from all of the snow) drainage zones.  When you add 0.50-1″ of rain atop the melting then problems could arise Wednesday into Thursday.  Additionally, we’ll need to prepare for the likelihood of dense fog Wednesday as milder air surges north over a deep snow pack.

3.) For anyone thinking spring is setting in during our mid week thaw will need to think again. Latest model data continues to suggest we reverse things quickly later this week and for the upcoming weekend.  In fact, some model data, including the European, suggests central Indiana is under the gun for a weekend winter storm.  We’ll continue to monitor closely…

021614ECSatWinterStorm022214

4.)  Additionally, prospects continue to grow for another extended period of well below normal cold and renewed wintry precipitation chances in the long term (into March).  Both the GFS and European models are in agreement on the mid to long range pattern with a trough settling back into the eastern half of the country.

02161412zGFSEC

Permanent link to this article: https://indywx.com/2014/02/16/sunday-afternoon-thoughts/

Cold Today; Messy Monday Ahead.

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Forecast Updated 02.16.14 @ 11:15a

Cold Sunday…Fresh off celebrating our snowiest winter on record (surpassed last night at IND at 51.6″ and the Record Event Report can be found here), we’ll enjoy a dry day, but blowing and drifting snow will remain an issue in the open country. A few breaks in the cloud cover can be expected this afternoon on what will otherwise be a rather cloudy day.  Highs will only climb into the lower to middle 20s (well below the average high of 40 and closer to the normal low of 24).  Yes, our cold, snowy winter just keeps on keepin’ on!

Snow And Ice Issues Monday…A storm system will move through the region Monday and deliver a mixture of precipitation types across central Indiana.  The way we see things unfolding as of this forecast update brings a wintry mix of sleet and snow into the city around noon with periods of moderate to even heavy wintry precipitation falling into the mid to late afternoon hours before we begin to see the shield of moisture push northeast.  This will be a “thump and go” type event.

As for precipitation type, this remains a challenge and will require much fine tuning later tonight and through the day tomorrow (another now cast scenario).  We’re thinking mostly snow is the dominant form of precipitation from the northern suburbs of Indianapolis and points north.  Here, 2-3″ of wet snow is possible, polished off with a light glaze of a freezing rain/sleet mixture before precipitation ends.  For the city, itself, we think around 1-2″ of snow is possible with a glaze of freezing rain of around a tenth of an inch. Farther south, to include the southern Indianapolis suburbs, an icy mixture of sleet and freezing rain will be the concern with glaze potential approaching one quarter inch.  Again, we caution this is our best idea at this point and we’ll post some fresh thoughts later this evening.

Needless to say, tomorrow stands to include treacherous driving conditions in and around central Indiana and the National Weather Service will likely issue Winter Weather/ Freezing Rain Advisories later this afternoon to account for the wintry conditions anticipated tomorrow afternoon.

Flooding Concerns On The Rise…With such a deep snowpack across central Indiana, combined with a frozen ground, flooding concerns will be on the rise as early as the middle to latter part of the week.  We think dry and chilly (albeit milder) conditions will be with us Tuesday, but low clouds, fog, and drizzle likely develop by Wednesday as milder air streams north over the snowpack locked in across the region.

By Thursday, our attention turns to the potential of heavy rain and a couple of thunderstorms as a cold front blows through the region.  Early ideas of Thursday rainfall numbers would suggest anywhere from .50-1″ of rain is laid down and when combined with the heavy snow pack and milder air, flooding concerns will certainly be present.  Needless to say, if you live in a flood prone area, please monitor the situation closely later this week.

Winter Blows Back In…As promised, the briefly milder shot of air would be just that- brief.  We continue to monitor data that suggests a colder, more wintry, pattern blows right back into the region to wrap up February.

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Permanent link to this article: https://indywx.com/2014/02/16/cold-today-messy-monday-ahead/

Valentine’s Day Snow

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Forecast Updated 02.14.14 @ 11:00a

Accumulating Valentine’s Day Snow…The Canadian led the charge and other modeling has followed suit.  The region will deal with accumulating snow Valentines Day as low pressure moves southeast out of Missouri into the Tennessee Valley.  We think snow will fall at a good clip, periodically heavy, and begin around mid morning around the city.  In fact, a strip of 2-5″ of snow is likely to be laid down between Indianapolis and Louisville later today.  Latest radar trends from upstream and banding features suggest snowfall amounts may reach 6″ along the I-70 corridor. Needless to say, if you have travel plans this afternoon plan for snow covered roads and slick travel.

A fresh shot of arctic air will drill south into the region tonight and result in Saturday “wake up” temperatures in the single digits with a biting northwest wind.

Another Fast Moving Clipper…After a mostly dry Saturday, we forecast light snow to build back into the region Saturday night into early Sunday.  This will only be a light snow event and most amounts will be in the dusting to 1″ category.  The sun should quickly return Sunday afternoon, though it’ll remain colder than normal.

Foggy Start To The Week…As a southerly air flow transports milder air north and over the snow pack across central Indiana fog will develop.  It’s possible some freezing drizzle is dealt with Monday morning before temperatures rise above freezing.  Prepare for a downright gloomy start to the work week.  A cold front will push through the region Monday evening and lead to a period of showers, potentially transitioning to light snow or a light wintry mix Monday night as cold air sweeps back in.

A Spring Tease…A spring tease will have many Hoosiers wanting to break out the shorts by the mid week period.  In fact, highs will zoom into the 60s Thursday, courtesy of a strong and gusty southwest breeze.  The downside?  A line of showers and gusty thunderstorms later in the day.  While we still have a week to monitor this situation, the possibility is there for a few storms to reach severe levels across the Ohio Valley region.  Stay tuned as we monitor this developing weather situation.

Looking longer term, we anticipate the briefly milder spring “tease” to be just that.  Signals are increasingly favorable for a prolonged period of cold, wintry conditions building back into the region as we put a wrap on February and head into March.

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Permanent link to this article: https://indywx.com/2014/02/13/valentines-day-snow/

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