Archive for December, 2012

Looking Back…Cincinnati Tornado
December 31, 2012

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The tornado developed just northeast of Westville, OK at about 6:05 am CST on the morning of December 31, 2010.  The tornado tracked rapidly northeast damaging a home, tossing four vehicles, snapping large power poles, and snapping and uprooting large trees in Adair County OK.

The tornado moved into Washington County AR about 2 miles southwest of Cincinnati at about 6:08 am CST and then impacted the town of Cincinnati at about 6:10 am CST.  Several permanent homes were destroyed, a mobile home was destroyed, several other permanent homes were damaged, numerous trees were snapped or uprooted, numerous power poles were snapped, barns and outbuildings were destroyed.  Two people were killed in the mobile home that was destroyed and a third was killed either in or near a barn while he was tending to his cattle.  At least 7 injuries also occurred.  The tornado was about 300 yards wide when it went through the town.

The tornado continued to move quickly northeast and widened to about 500 yards, severely damaging several other permanent homes, destroying at least six chicken houses, snapping or uprooting numerous trees, snapping numerous power poles, and destroying a number of outbuildings. The tornado struck several other mobile homes, severely injuring a woman who passed away as a result of those injuries in the hospital January 4th.  The tornado passed into Benton County AR just north of Wedington at about 6:17 am CST.

In Benton County, the tornado severely damaged a couple of homes, destroyed a mobile home, destroyed barns, snapped and uprooted numerous trees, and snapped power poles. Two injuries occurred in the mobile home that was destroyed on Winwood Ranch Road.

The tornado continued northeast, crossing back into Washington County where trees were blown down. The rapid northeast movement then took the tornado back into Benton County, where a home lost its roof, several outbuildings were destroyed, and trees and power poles were snapped on Robinson Road about 2 miles south of Highway 412. The tornado then finally moved back into Washington County where it destroyed a home on the western city limits of Tontitown, blew a mobile home off its piers, and snapped or uprooted large trees before dissipating about 3 miles northwest of Tontitown at about 6:27 am CST.

Drew Michaels

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Monday’s Winter Weather
December 30, 2012

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The last week has been super active regarding winter weather, so why would the last day of 2012 be any different?  A storm system to our west will bring  the area a mix of rain, sleet, and snow for Monday!  I posted the timelines above to get you prepared.  Thankfully there won’t be a major morning commute tomorrow with it being  New Year’s Eve, and we don’t expect major issues on the roads.

The models continue to show rain developing after midnight.  The atmosphere will start out dry, and that will allow the temperatures to slowly drop within the atmospheric column due to evaporational cooling.  Overnight lows will be around 31 or 32 degrees.  While some freezing rain is possible, the set-up isn’t very conducive for major freezing rain.  The rain will likely switch over to a mix of sleet and snow after 6 am.  As of now the winter weather potential will be confined to I-40 and north.

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Minor accumulations below an inch on grassy surfaces are possible.  Benton and Carroll counties could see some slightly higher totals as the snow will take a little longer to change over to rain.  The 850 mb temperatures will slowly warm throughout the afternoon.  That should turn the snow back over to rain by the afternoon and evening.  Rain should be done for your New Year’s Eve plans.

Drew Michaels

Follow us on Twitter @4029weather and on our 4029 Weather Updates Facebook Page

SNOW, SLEET, OR RAIN? HOW ‘BOUT ALL THREE
December 29, 2012

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Travel could become difficult Monday morning as our next storm system ushers in moisture into an environment over northwest Arkansas and the River Valley that may not be very cold… but it will be dry.  I’ll explain why a dry atmosphere is important when it comes to forecasting snow and sleet in moment.

Out ahead of this storm system we will warm up Sunday afternoon as our winds change direction out of the south.  Interestingly, the river valley should be a little cooler than NW AR because they will sustain an east wind throughout much of the day.  This is important to the forecast temperatures here, because that east wind will be over running a large area of snow still on the ground across central Arkansas before arriving in the river valley, making it a shade cooler.  Though the change in wind direction will make it certainly warmer than it was today across the entire viewing area, it is going to do little to increase the moisture, especially over northwest Arkansas.

Sunday night precipitation will begin to overspread much of central Oklahoma and begin arriving in eastern Oklahoma and western Arkansas in the early morning hours of Monday.  As this precip falls through the relatively dry air mass in place over our area much of it will be evaporated away until more precip comes in behind it and saturates the atmosphere enough to allow it to make it down to the ground, possibly falling initially as snow or sleet.  And here’s where the dry air comes into play…

All that evaporation causes the atmosphere to cool.  It’s known as evaporative cooling and you’ve probably experienced it once already today without even knowing it.  Ever wonder why you’re so cold after getting out of the shower?  It’s because all that water is slowly evaporating off your skin, and in the process stealing heat from your body.  In this same way, as the snow and rain evaporates into vapor, it’s stealing away heat from the surrounding atmosphere.  And the drier the air mass beneath the clouds the more evaporation is likely to occur.  Combine this with a healthy tongue of moisture in the mid levels of the atmosphere lifting north out of Texas and you’ve got a recipe for a great deal of evaporation, and therefore cooling.

This effect should be enough to create snow over areas especially north of I-40 early Monday morning.  It should change to rain fairly quickly in the river valley, but, could hold on as snow or sleet a little longer from Fayetteville northward.  This could mean an accumulation of snow and sleet Monday morning that causes roads to become slick.  For this reason especially we are monitoring this system very closely for any changes to its track and intensity.  Right now it appears the snow/sleet should transition to all rain by the afternoon.

We’ll continue updating you on this system throughout Sunday and into Monday morning during all our news casts.  You can also get those updates on the web at www.4029tv.com

Meteorologist Darby Bybee

Light Freezing Rain Possible Thursday Night/Friday Morning
December 27, 2012

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If you have to travel late tonight or Friday morning be mindful of the fact that light freezing rain will develop over the River Valley after midnight and continue through about 10am.  Most of the precipitation will fall over central Arkansas, but, the River Valley should still pick up light accumulations.  And it doesn’t take much to cause the roads to be slick when it comes to freezing rain.  North of the line drawn in the image above a light mixture of sleet and snow could form Friday morning, though, total accumulations should be generally below 1/2″ if any at all.  Drive safe out there folks, the Friday morning rush hour could be a slow one.

Morning Snow Update
December 24, 2012

Latest models this morning are still showing the potential for some heavy snowfall across the area on Christmas day.  This morning the National Weather Service upgraded a Winter storm watch to a warning for most our counties, excluding Benton and Delaware county.

Watches and Warnings

This warning indicates that some areas could get up to 8 inches of snow.  This morning the NAM model has this system farthest to the northwest, but as of late it has been trending the area of heaviest snowfall to the south.

NAM SNOWIN forecast valid 06 UTC Wed 26 Dec 2012

While the GFS has been inching moving snow fall totals to the north.

GFS SNOWIN forecast valid 06 UTC Wed 26 Dec 2012

Since the models are trending towards some sort of consensus I’m sticking with Darby’s line of thinking and taking a blend of the two.  So this means extended heavier snowfall totals to Northwest Arkansas. On average 3-6 inches of snow will be possible tomorrow with some places, especially the higher elevations, accumulating up to 8 inches.

Snow tomorrow will be a wet fluffy snow.  Also, along with travel impacts this system could produce some power outages.  Winds will be really gusty along this front and that could knock over trees onto power lines.

Meteorologist  Brittany Bell

You can follow us on twitter @4029weather and also get updates on our Facebook page. 

Snow forecast for Christmas Day/Night
December 23, 2012

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After taking a look at the latest runs of some of the models it appears we’ll have to go with a blend of all of them.  As you see in the picture above the NAM model has been trending the heaviest snowfall farther south while the GFS has been trending it northward, and this trend continued to show up in tonight’s model runs.  So, we’re going to go with a blend for now.

Look for the precipitation to move into the River Valley first around 7 am and into NW AR by about 10 am.  It will start off as light rain, then transition to sleet or a sleet/snow mix, then to all snow by the afternoon.  Look for the change from rain to snow to happen first in Oklahoma and NW AR.

By the afternoon the snow could become heavy as a band of snow develops in the River Valley and moves through NW AR.  This band could be dropping snow at more than 1” an hour at times.  Given the amount of cold air aloft and the amount of energy it’s possible lightning could be witnessed in the heaviest snow.

The snow should begin tapering off after midnight and will have completely exited the region by Wednesday morning.  The map of expected snowfall you see above is not set in stone, and could be moved northward or southward as much as 40 miles.  But, it’s our best guess for right now.

What does this mean for travel?

Plan ahead.  For those who can travel early, before the storm starts Tuesday morning, get to where your going by Christmas Eve or before 9am Christmas Day.  And plan to stay an extra day to allow for roads to be properly treated.  For those who absolutely have to travel Christmas afternoon/night be prepared for slow travel on the interstates and limited treatment of side roads.  It’s possible some parts of the region will only be accessible by 4 wheel drive vehicles during this timeframe.  Best advice, get where your going early, stay where your at late.

And try to enjoy your family, it is Christmas after all.

Meteorologist Darby Bybee

Big Changes
December 23, 2012

Today will be the last day of the 50s and 60s so if you like the mild weather enjoy it while you can.  A dip in the jet stream currently off the west coast will dive in the central Plains ushering in cold air and a chance for snow on Christmas day.

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Models are still bringing a surface low through our area, but the amount of snow we get is all dependent upon the track.  This morning the GFS stayed pretty consistent bringing the low through the Red River Valley putting accumulating snow right over our area.

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But the NAM has shifted this low to the northwest, thus putting the heaviest snow in north central Oklahoma through Northwest  Arkansas.  This would leave the River Valley and southeast Oklahoma with a dusting of snow.

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At this point I’m leaning more towards a blend of the two given the recent change.  This would still put us in the position for some snow accumulations.

Meteorologist Brittany Bell

You can follow on twitter @4029weather and also get updates on our Facebook page. 

Weekend & Christmas Forecast
December 22, 2012

Get ready for a mild weekend as highs will reach the upper 50s and 60s.  But we will feel a slight cool down tomorrow as a weak cold front enters the region.  This front will be starved of moisture Sunday so we won’t see any rain, but we will notice an increase in clouds.

Forecast valid Sunday 12Z

The focus right now is still on Christmas day.  Models are still indicating a chance for a white Christmas all thanks to a low pressure tracking to the south of us. This current track puts us in the backside of the low which is an ideal spot for snow.  Here we have a mix of  cold air and moisture which provides the perfect combination for snow.  If this verifies we could see 2-4 inches of snow with the heaviest accumulations in the River Valley and central Arkansas.

Snow totals are all dependent on the track.  Any minor shift could either decrease or increase the amount of snow we get on Christmas day.

Meteorologist Brittany Bell

You can follow us on twitter @4029weather and also get updates on our Facebook page. 

Model Forecast Snow Totals for Christmas Day
December 21, 2012

ImageHere’s the latest model forecast of snow totals Christmas day/night.  This is from the GFS model.  At this point much uncertainty regarding the speed of this storm system remains.  This is important for two reasons…

If this system slows down a little we would expect it to strengthen more than what our current models are forecasting, which could lead to higher snow totals.

On the other hand, if the storm system gathers more momentum there would be little time for significant strengthening once the low pressure system begins developing along the lee side of the southern Rockies.  This would lead to lesser totals in our region and higher totals farther southeast across central AR.

It’s always a balance folks.  And the last time such a balance occurred on Christmas Day in northwest Arkansas and the River Valley was 1975, so, a rare one at that.

We’ll stay on top of it throughout the weekend with additional webcasts on 4029tv.com and updates to our facebook pages… facebook.com/4029news and facebook.com/4029WeatherUpdates

Meteorologist Darby Bybee

 

A Nice Weekend
December 21, 2012

Despite a cold start to your day the weekend will feature warm temperatures and a lot of sunshine.  We can thank this warm up to southerly winds that will help to usher in some mild air into our region.

Forecast valid Saturday 12Z

But our forecast isn’t looking so quiet for Christmas eve and Christmas.  Over the past few days models were flip-flopping on the possibility for snow on Christmas, but today they have started to come to a consensus   When this happen that does up our confidence forecasting long range.

Right now models are showing an area of low pressure sweeping to the south of us bringing in some moisture in the  midst of  some cold air.  If this pans out we could have some snow on Christmas evening.

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This far out things can still change, but at least there is a chance for some winter weather for you snow lovers out there.

 

Meteorologist Brittany Bell

You can follow us on twitter at 40/29 weather and also get updates on our  Facebook page.