Category: Heavy Rain

Feb 12

Next Week’s Spring Tease Is Just That, A “Tease…”

There’s no doubt we’re looking at a brief pattern change next week that will result in air temperatures that will have many of you craving spring.  That said, the key word in that sentence is “brief” and a colder, more wintry pattern looks to return to wrap up February and head into March.

Before we discuss the return of the cold and potentially wintry regime for late month, let’s focus on the milder conditions.  Data suggests we may be looking at highs zooming all the way into the lower to middle 60s towards the 20th-23rd time period.  The spring tease is likely to come at a cost as the milder southerly breezes likely result in lots of dense fog and areas of drizzle as a deep snowpack remains locked in place.  Flooding concerns may also become a concern next week, especially if we inject moderate to heavy rain into the region.  10-day rainfall numbers do have to make us a little nervous as a blend of model data suggests 1″-1.5″ down between now and the 22nd.  We’ll continue to monitor things.

Finally, it should be noted that while a brief “relaxation” of the seemingly unending winter is on the way, the long term pattern continues to suggest a cold and wintry time of things continues overall.  Next week appears to be an “island of warmth in a sea of cold” type pattern.  Latest ensemble data continues to back this idea up.  That’s not saying we’re going to deal with the type of severe cold we’ve seen over the past several weeks, but instead means we’re going to go back below normal as we get set to wrap up February and head into March.

The latest GFS ensembles show the evolution of things well.  The “double secret probation” European model also shows something similar.

gefs_z500anom_nh_33gefs_z500anom_nh_49gefs_z500anom_nh_65

Note the ridge and associated spring “tease” is replaced with a cold and more wintry looking eastern trough rather quickly.  Circle the 24th on your calendar for the potential of a widespread storm system.  Far too early for details or questions, but the pattern looks to produce some busy times around this point.  Before that we have plenty of weather in front of us to deal with… weekend snow opportunities, foggy/ drizzly weather to accompany the initial surge of milder air next week, and a spring tease by late next week!

Permanent link to this article: https://indywx.com/2014/02/12/next-weeks-spring-tease-is-just-that-a-tease/

Dec 21

Dangerous Flood Event Developing

Widespread rainfall totals are approaching 1″-2″ since the rain begin Friday across central Indiana.  When you look at the big-scale radar picture (snapped shortly after 8 o’clock this morning), you can understand the concern that’s ahead later this evening into Sunday, from a flooding perspective.

usa_None_anim

Latest projected rainfall numbers remain very consistent on the message we’ve been passing off  to you, the viewer, for a few days now…widespread 3″-4″ totals, with locally heavier amounts.

We think steady moderate to heavy rains continue for the better part of the day, but we note our short term, high-resolution, models targeting this afternoon and overnight for some extreme rainfall rates to develop.  Here’s a look at the simulated radar valid 7pm this evening:

hires_ref_indy_19

When you consider the snow melt and the rain that will have already fallen by this point, the stage is set for a very dangerous overnight flooding situation.  Flooding any time of the day is dangerous, but particularly so at night.  If you live in a flood prone area, PLEASE make sure to have a plan in place and consider perhaps spending the night with family or friends tonight as rapid water rise is certain to occur.

Permanent link to this article: https://indywx.com/2013/12/21/dangerous-flood-event-developing/

Dec 20

Colder Than Normal Pattern Set To Return

Before we go into the cold pattern that is looming, our current forecast of severe flooding developing across central Indiana this weekend remains.  Our projected precipitation numbers remain in the 3-4″ range for most of central Indiana, but there will be some higher totals reported.  Combine that with the recent snow melt and the stage is set for potentially a severe and dangerous flooding event.

As we look ahead to the next weather “challenge,” it has to do with temperatures.  As we’ve talked about in previous posts, our weather pattern flipped to one that has been predominantly colder than normal back in the middle of October.  Despite a handful of days, cold has dominated the pattern.  Before our current thaw temperatures were averaging 5 degrees below normal for the month of December.  While the recent thaw is certain to reduce the anomalous cold, the last week of December could send us right back to readings much colder than average, helping put the exclamation point on the month as far as cold goes.

The latest 8-10 day ensemble plots showcase a very cold pattern to end December.  Cross polar flow gets involved, helping lead to some bitterly cold air around these parts.  We note excellent agreement between the GFS and European forecast models, helping to further increase our confidence in the cold pattern ahead.

test8

But it doesn’t stop there…  We note long range data suggesting this cold pattern continues well into January.

The latest European forecast ensembles showcase the cold continuing to reload into the first week of the month.  This is an impressively cold look, considering we’re still a couple weeks out and that these are a multitude of individual computer model runs averaged together to come up with this solution.

eps_t2min_anom_east_61

As we watch the evolution of the cold pattern, it’s important to turn to the “goings-on” with the upper air pattern.  Note the reorganization of the polar vortex and, equally as important, the placement of the polar vortex.  For the purpose of giving you a couple of different viewpoints of the evolution of the pattern we’ve pasted a Northern Hemisphere and North America perspective.

Note how the polar vortex reorganizes itself and decides to set up shop over Hudson Bay and Baffin Island by early January.  This is significant in that it promotes multiple reinforcing shots of arctic air into the eastern half of the country and backs up what the data above would suggest in the cold pattern that appears to be looming as we move forward…

Sunday, December 22nd

12

Friday, January 3rd

34

What does all of this mean?  That the current “thaw” is very brief.  The seeds were being planted for a return of the cold pattern earlier this week and it all begins Sunday night.  As the data above would suggest, the arctic cold appears to reinforce itself as we go through time and an overall prolonged colder than normal pattern appears to be setting itself up.

Additionally, we’ll have to handle winter storm systems as they come (and they will), but the pattern is one that very well may promote fast-moving clipper systems moving southeast out of Canada.  While most of these clipper systems don’t drop tremendous snowfall totals, the more potent clippers can deposit several inches of snow and serve to “feed back” and turn what’s initially a cold, dry pattern into one that’s suddenly snowy.  We’ll keep an eye on that.  Furthermore, the southern stream may also decide to add a little “excitement” into our forecast late December or early January.

Needless to say, there’s a lot of weather to talk about in the days ahead…

Permanent link to this article: https://indywx.com/2013/12/20/colder-than-normal-pattern-set-to-return/

Dec 20

Model Data Not Backing Down On Flooding Rains Ahead

A scan over multiple computer models this morning shows that forecast models remain consistent of the idea of a weekend deluge across central Indiana.  Unfortunately, when combined with the snow melt, if even the numbers are half right, we’ll have to deal with significant flooding this weekend, especially Saturday afternoon through Sunday.

Here’s a look at the data.  We average multiple computer models together to come up with our precipitation forecasts (both rain and snow) that you see in our daily 7-Day Video Forecasts (available to the right of this post).

CAN1EC1gfs_total_precip_east_11hires_ptype_acc_indy_20NAM1plotter

Needless to say, when looking over all of the data above, we still feel confident in the forecast we have out…widespread 3-4″ rainfall with locally heavier totals.  Preparations should have already begun if you live, or work, in a flood prone area, but if not, please do so today.  The question remains not if we’ll see flooding, but how severe the flooding will be.

Permanent link to this article: https://indywx.com/2013/12/20/model-data-not-backing-down-on-flooding-rains-ahead/

Dec 19

Thursday Morning Weather Rambles

As always, your latest 7-Day Video Forecast can be found to the right in the video player.   1.) A milder southerly air flow allowed us to remain above freezing…

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Permanent link to this article: https://indywx.com/2013/12/19/thursday-morning-weather-rambles/

Dec 18

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.

Permanent link to this article: https://indywx.com/2013/12/18/a-lot-of-weather-to-talk-about/

Dec 18

Significant Flood Situation Ahead…

Your latest 7-Day video forecast can be found in the video player to the right of this post.

We’ve known for over a week now that we’ll have to deal with a pre-Christmas storm. Latest guidance suggests our region undergoes a 3-4 day thaw with a decidedly warmer southwest flow ahead of this storm.  Additionally, with the more northern track of the surface low, we’re looking at nearly all of the precipitation associated with this storm falling as rain.  Combine our frozen ground with a significant early-season snow pack and multiple inches of rain ahead in the Thursday night through Sunday time period and the stage is set for a significant flood situation this weekend.

Here’s a look at what the latest forecast models show.  We’ve posted the GFS, Canadian, and European models below to display total rainfall between Thursday through Sunday.  The majority of this rain falls in two waves- Friday and again late Saturday into early Sunday.

gfs_total_precip_east_22cmc_precip_by10_east_1ecmwf_tprecip_indy_21

If the rainfall numbers are even half of what is projected above, we’re looking at a significant flood situation.  Needless to say, if your property is in a low-lying area, or one that is prone to flooding, I would begin to prepare now for major water rise in the days to come.

Much more later!

Permanent link to this article: https://indywx.com/2013/12/18/significant-flood-situation-ahead/

Dec 16

Major Storm Brewing This Weekend, But Details Are Murky…

During the late summer and early autumn months we were trying to look at the big picture and potential drivers in the overall weather pattern for the upcoming winter and openly admitted the challenges that were ahead.  Here we are now into the second half of December and a much colder and snowier-than-average month is a virtual lock at this point.  Furthermore, consider this has all taken place without the presence of a favorable NAO or PNA.  Sometimes you have to look for other drivers in a pattern- in this case, the EPO, as well as a growing early fall snow pack across the border to our north.  Additionally, we made mention of the likelihood of a southeast US ridge periodically making itself known through the winter of ’13-’14.  You can read all of our thoughts posted earlier this fall here, or by clicking the Thoughts On Winter ’13-’14 page above.

As we look ahead towards the upcoming wintry challenge, we’re confident of the overall pattern, but the sensible weather that’ll ensue is still up for great debate.  “Gut” tells me central Indiana will be looking at a rain to freezing rain scenario, but this is far from set in stone, and sometimes forecasters who go simply off their instinct can get burned.  The pattern is one that (once again) will feature a pressing arctic front against resistance from the southeast US ridge.  With this type of scenario, I would advise against looking at each and every individual operational model run, but instead invest time studying the ensembles- an average of several multiple model runs as opposed to just one operational model run.   I can guarantee a variety of wild solutions ahead in the days to come, based off the operational runs. (Heck, just the past 24 hours have been reason enough to have the dramamine on hand :-)).  That said, let’s take a look at the latest GFS and European ensembles, two models that we rely heavily on in the mid range weather pattern.

First, the GFS, valid Saturday through Monday.

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Now, here’s a look at the latest European ensembles (left), again valid Saturday-Monday.

Geopotential32at32500hPa_North32America_120Geopotential32at32500hPa_North32America_144 Geopotential32at32500hPa_North32America_168

So what do all of these cool maps tell us?  Simply put, that “wintry mischief” is brewing for the weekend.  That much we know, but the details have to be ironed out.  It’s likely heavy snow and a significant ice storm looms for some of the Mid West and Ohio Valley for the upcoming weekend.  Is that Indianapolis or Chicago?  Perhaps in between?  It’s too early to know.  Additionally, in the “warmer” sector, heavy rains are likely to combine with an impressive early season snow pack for some to lead to flooding concerns.

A couple of additional items to note. Many times at this stage in the game (still 5+ days out) with this type of pattern, forecast models really struggle with handling low level cold air.  Cold air is very dense and, in this type of set up, can easily drain much further east and south than forecast at this juncture.  Additionally, sometimes the modeling can put too much “umph” into the associated surface wave that moves along the arctic front resulting in a further north track than what may actually occur when the event draws closer.  Just something to keep an eye on as we draw closer…

Needless to say, it’ll be particularly important to keep a close eye on the developing weekend forecast as we move forward.  It’s likely folks in the Ohio Valley region have to deal with significant precipitation amounts in the Saturday-Monday time period, including rain, freezing rain, and snow.

Permanent link to this article: https://indywx.com/2013/12/16/major-storm-brewing-this-weekend-but-details-are-murky/

Nov 14

Heavy Rain And Severe Outbreak Sunday

We continue to analyze the latest data concerning our pending severe weather episode ahead Sunday.  Today’s information continues to point towards the threat of not only a damaging straight line wind event, but the potential of multiple tornadoes across the central Ohio Valley.  The tornado threat would most likely occur with any individual super cells that develop Sunday afternoon.  The damaging straight line wind event would then be associated with what’s likely to be a squall line associated with the cold frontal passage Sunday night.  Needless to say, Sunday will be busy weather day across not only the Hoosier state, but for many folks across the Mississippi River Valley into the Ohio Valley.  Additionally, widespread heavy rain is also a good bet.  Let’s look at some data:

First, let’s look at some rainfall numbers.  The ECMWF (European forecast model) and GEM (Canadian forecast model) are the most aggressive with rainfall totals approaching the 2″ mark for many areas of central Indiana between Sunday and Monday.  The GFS isn’t as bullish, forecast a little more than half an inch on it’s latest run.  Officially we’ll go with a blend of all three models and suggest widespread 1″ type rains across central Indiana during the Sunday-Monday period.

ecmwf_tprecip_indy_21cmc_total_precip_east_15gfs_total_precip_east_15

Before we go further, we also want to highlight that winds will be strong and gusty Sunday even well away from any thunderstorms.  Winds will likely gust to 40-50 MPH simply by the tightening pressure gradient as surface low pressure begins to “bomb out” (rapidly intensify) on it’s journey into the Great Lakes region.

The dynamics are somewhat scary with this event and, as stated above, suggest not only an enhanced straight line damaging wind event, but also the potential of multiple tornadoes associated with any super cells that get going Sunday afternoon, well ahead of the squall line.  Despite a cold, dry air mass in place currently, the aforementioned strong southerly winds will help transport dew points into the lower to middle 60s come Sunday afternoon.  This will only help add fuel to the fire for storm development.

ecmwf_dew2m_indy_14

Let’s take a look at the official Severe Weather Outlook for Sunday, courtesy of the Storm Prediction Center.  Some highlights from their most recent discussion:

SOME UNCERTAINTY LINGERS...BUT TRENDS IN THE MEDIUM RANGE FORECAST
   GUIDANCE ARE INCREASINGLY SUGGESTIVE OF THE DEVELOPMENT OF AN
   ENVIRONMENT SUPPORTIVE OF AN OUTBREAK OF SEVERE THUNDERSTORMS ACROSS
   PARTS OF THE MIDDLE MISSISSIPPI VALLEY EASTWARD THROUGH MUCH OF THE
   OHIO VALLEY ON SUNDAY.
A 90+ KT 500 MB JET STREAK NOSING THROUGH THE OHIO VALLEY...COUPLED
   WITH STRENGTHENING SOUTHERLY WARM SECTOR 850 MB FLOW...PERHAPS IN
   EXCESS OF 70 KTS ACROSS PARTS OF THE OHIO VALLEY INTO THE LOWER
   GREAT LAKES...WILL CONTRIBUTE TO VERY STRONG DEEP LAYER WIND FIELDS
   AND SHEAR.  IT ALSO APPEARS INCREASINGLY PROBABLE THAT THIS WILL
   COINCIDE WITH AN INFLUX OF SEASONABLY HIGH MOISTURE CONTENT AT LEAST
   AS FAR NORTH AND EAST AS THE LOWER OHIO VALLEY...CONTRIBUTING TO
   SUFFICIENT CAPE FOR VIGOROUS STORM DEVELOPMENT.  SUPERCELLS WITH A
   RISK FOR TORNADOES WILL BE POSSIBLE...PARTICULARLY IN EARLY STAGES
   OF CONVECTIVE DEVELOPMENT...PERHAPS AS EARLY AS MID DAY ACROSS PARTS
   OF THE MIDDLE MISSISSIPPI INTO LOWER OHIO VALLEY VALLEY
EVENTUALLY...THOUGH...ACTIVITY PROBABLY WILL EVOLVE INTO A SQUALL
   LINE WITH DAMAGING STRAIGHT-LINE WINDS BECOMING THE MOST PROMINENT
   SEVERE THREAT.

day48prob

Permanent link to this article: https://indywx.com/2013/11/14/heavy-rain-and-severe-outbreak-sunday/

Nov 05

Wednesday Forecast: Rainy Midweek

Updated 11.05.13 @ 3:43p

Zionsville, IN Clouds are hanging tough this afternoon and rain isn’t too far off. Rain will increase Wednesday, becoming widespread the second half of the day. MUCH colder air will then blow into the region Wednesday night and Thursday.

Status-weather-showers-scattered-iconWednesday: Rain likely (0.55); 34/ 58

Wednesday will feature another gloomy day with rain overspreading the region from west to east. Scattered showers will be present through the morning hours before giving way to steadier, heavier rainfall during the second half of the day. Latest data suggests the cold front is speeding up from the last forecast update and this should result in a FROPA (frontal passage) Wednesday night. It’ll also be a windy day, with southwest gusts of 25-30 MPH during the day, shifting to the northwest Wednesday night.  Colder air will pour into the state behind the front, setting up a chilly, blustery Wednesday night and Thursday.

Status-weather-clouds-iconThursday: Partly cloudy; 33/ 47

A blustery northwest wind will blow Thursday and combine with a partly cloudy sky and an unseasonable chill to create a rather cold day. Winds will gust upwards of 20 MPH from time to time.

 

Status-weather-clouds-iconFriday: Partly cloudy; 30/ 51

A hard freeze will greet us as we prepare to wrap up the work week. Widespread lows around 30 will be commonplace before partly cloudy skies help temperatures rise into the lower 50s Friday afternoon.

 

Status-weather-clouds-iconSaturday and Sunday: Partly cloudy; 40 Sat, 36 Sunday/ lower to middle 50s

High pressure will remain in control of our weather Saturday.  While a weak storm system will pass through the upper Great Lakes region, it’ll remain well north of our area. Southwest breezes could gust up to 20 MPH Saturday afternoon. Otherwise, we’re looking at some mid and high level cloudiness and middle 50s Saturday afternoon and lower 50s Sunday.

Status-weather-clouds-iconMonday: Partly cloudy; 38/ 50

Dry and slightly cooler than normal conditions will greet us as we kick off the new work week.

 

Status-weather-showers-day-iconTuesday: Scattered shower (0.10); 36/ 50

The early look at next week shows more questions than answers.  For now we forecast scattered showers as our next weather system approaches from the west, but we caution this is a low-confidence forecast.  Be sure to stay tuned as we update things moving forward.

 

Permanent link to this article: https://indywx.com/2013/11/05/wednesday-forecast-rainy-midweek/

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