Sunday, January 31, 2010

Why is the moon orange?

This is similar to the colors we see during a sunset.

The moon is actually emitting all different visible colors which combine to make white. As the moon is overhead we are able to see a white moon, but a lower moon position make the moon's light travel through more of the atmosphere. Colors with shorter wavelengths are scattered in the atmosphere, which is why we end up seeing red, yellow, and orange colors remaining. Particles in the atmosphere, including dust, can help scatter the light.

A sunset is similar to this because the sun's light rays must travel through more of the atmosphere as the sun's begins to set. So we see orange and red colors.

Saturday, January 30, 2010


Very cold day here in Mississippi. Our friends in Tupelo haven't been above 30 since 7am today.

The temperatures have been on a steady decline all day, which finds us currently in the lower 30's. We will have a midnight high and low today since we were at 46 last night at midnight. I'll also expect us to be well below freezing for much of the night.

We are still stuck under a pocket of low clouds for the next few hours, but we will slowly see things clear out as a high pressure system builds in from the west. Sunday should involve clearing sky conditions with a high near 50.

Wednesday, January 27, 2010

Friday rain maker

Beautiful weather in the Pine Belt today. We reached a high of 62 at the station.

Things will be changing here soon and begin setuping up for another rain event. Moisture will begin to return as our wind flow gains a southerly component and an upper level western flow. Clouds will also be building throughout the day on Thursday. Wednesday was very clear, but Thursday will be a mixed bag of sun and clouds. Expect a Low pressure system to build to our west and then move right through South Mississippi on Friday afternoon.

I expect the rain to move in the viewing area on Friday afternoon and stick around for the night. As the Low pushes through Mississippi the NW side of the Low (Northwest MS) could see some snow flurries. At this point, I don't expect any of the white stuff Friday night in South Mississippi, but an unlikely southerly track from the Low could change the forecast a tad. But once again, I don't expect to see any major snowflakes during this event. Nick and Rex will have the updates on this tomorrow, and Tanner will follow up on things this weekend.

The latest Quantitative Precipitation Forecast has South Mississippi in the 2" window through Friday's rain event.

This weekend will be cool, but the long Range forecast have been difficult to determine at this time. I've noticed a difference from several model runs on what computers are thinking during the first week in February. I'm noting the Arctic Oscillation will be extremely negative, but the North Atlantic Oscillation (whichs helps lock cold air south) will be near neutral going into February. My opinion...I think we will be near climatology going into the 2nd month of the year with some chances to produce some numbers slightly below normal.

Sunday, January 24, 2010

Sunday Notes

A couple notes to be made about our forecast:

-Upper level flow will be from the NW until Wednesday morning when we shift back to a SW flow.
-Moisture will return Wednesday and Thursday for our next rain event.
-A health system will bring rain to the Pine Belt late on Thursday (Looks like another night event).
-Next weekend looks to be cool/cold behind the cold front passage.

Early Totals so far

Low level jet really pumped in more moisture here in the last few hours, which transpired with an extra boost to the showers running through the Pine Belt. So rain totals are extremely high for an hour of rain particularly at the station.
Here are some of the latest totals.

WDAM-TV: 1.31"
Pine Belt: 0.41"
Bobby Chain: 0.29"

Our station was right in the path of the heaviest rain. The Pine Belt Airport and Bobby Chain were just barely boarding the North and South boundary of the cluster of storms.

Saturday, January 23, 2010

Mesoscale Discussion

Latest Mesoscale Discussion (#0057) from the Storm Prediction Center includes this wording...


Rain line moving in

I'm currently watching a line of rain soon to be in the Pine Belt. A surface trough is producing a strict line of showers/storms all along the Mississippi River Valley. North Mississippi has the "heavier" portion of the line while we are in the scattered and "thin" area of the line. Instability values are low tonight in western MS and Louisiana, but eastern MS is more stable at this time. And wind shear values are extremely high, which can be an inhibiting factor for severe potential. It's difficult to produce when you have too much.

What do I expect?
I expect to see the line make it into the I-59 corridor after midnight and possibly near 1am. Before the main line we have the opportunity to experience some scattered showers. All in all, this will most likely turn into a typical scattered showers event, but the severe potential is unlikely all night long. Although, you might feel strong wind embedded along the rain line between 25-35mph. Rain totals will be slightly different across the region, but I don't expect anything extremely heavy.

Temps tomorrow will still be mild because the cold front is lagging behind the trough. Expect the cold front to move through late Sunday night and give Monday slightly cooler numbers.

Wednesday, January 20, 2010

Stormy Night

So far Southern Louisiana has seen two tornadoes. This section of Louisiana is in the middle of the most unstable air mass. East Texas and South Central Louisiana currently have CAPE (Convective Available Potential Energy) near 1500 J/kg and South Mississippi is only at 500 J/kg. We can see this played out when storms show strengthening in Louisiana but weaken after crossing the Pearl River. Instability is lagging a bit since the sun has been down, but this is enough instability to still be a concerned when you mix the instability with the available wind shear.

The storm relative wind shear (relative variable for rotation in the atmosphere) is expected to stick around till the early hours on Thursday. So we might have a long night of watching things tonight.

Afternoon Update

I expect the highest instability from the west will continue to filter into the Pine Belt. Storms developing late this evening and after sunset could be fed with enough usable energy to produce damaging wind and hail. An isolated tornado is still plausible, but highest storm relative vorticity (rotation variable) is greatest along the MS and LA coastline.

There is currently significant rotation indicated on radar with a supercell in Louisiana at this time, but I'm pretty sure there is no verification the rotation has reached the ground. The whole line in Louisiana will be migrating into South Mississippi in the next several hours.

Scattered Thunderstorms this morning

Well Wednesday has started on a cloudy note with temps near 60, and scattered storms are already moving into the region from the more unstable air mass in Louisiana. Heavy rain is falling just northeast of Baton Rouge and east of McComb late this morning. I expect scattered storms throughout the day in South Mississippi with more intensity plausible within storms this evening.

Highest instability is over in Arkansas and Louisiana at this time, but Mississippi will become progressively unstable into the afternoon and evening. A strong upper level jet from the Pacific will also move in and cause more upper lift in storm development. The upper level jet is typical for El Nino weather patterns.

What is the biggest concern? The biggest concern will be damaging winds associated with unstable air mass and upper level dynamics this evening. Severe hail thresholds could be met with the towering cumulonimbus clouds. An isoalted tornado is also plausible for tonight.

Rain totals? North Mississippi will accumulate the most rain of 2"-4" and South Mississippi should find totals between 1" and 2".

Timing? Scattered storms will be around all day and lasting through midnight.

Follow and for most updates today.

Monday, January 18, 2010

Focusing on Wednesday

My weather story tonight is headlined by Wednesday's cold front passage. The latest model run looks like instability and rotation will be available near midnight Wednesday night. This is a concern for Wednesday night's forecast, but I'm going to wait to see how things transpire tomorrow. I wouldn't be surprised to see a few isolated severe thunderstorms form along the cold front line. But, of course, we always have limiting factors.

Tuesday is still a setup day leading into the rain on Wednesday. Expect mostly cloudy conditions for a majority of the day tomorrow with temperatures back into the 60's.

Sunday, January 17, 2010

Sunday Night's Discussion

Well the cool and cloudy day wasn't the best outcome for many folks. I'm sure a few cloudy days makes us look forward to the sunshine, and I expect to begin seeing the sun as the day progresses tomorrow. Mostly cloudy skies will make way to partly cloudy conditions by the evening, and temperatures should top out in the lower 60's.

Monday and Tuesday are temperature forecast days where lower to mid 60's will be expected. Also, overnight lows will be in the 40's.

The atmosphere will deliver a good SW flow aloft and pull in significant moisture by Wednesday. Monday and Tuesday are basically going to setup for the cold front passage on Wednesday evening. The front on Wednesday could deliver nearly 2" with thunderstorms embedded along the front line. Instability will be greater during the midweek event compared to past Saturday's rain event. So we should expect higher rain totals.

Extended Forecast thoughts:
I was able to glimpse into the long range forecast. Looks like some variables are backing another shot of colder air into Mississippi around February 1st and 2nd. Ensemble forecast on support oscillations driving cold canadian air down the Mississippi River Valley. I wouldn't be expecting a carbon copy of what we experienced to start January, but we have a very good chance to be below average to start the month of February.

Saturday, January 16, 2010

Cloudy Day Tomorrow

Rain totals through the area aren't very high. Most have seen 0.30" so far today, but we will be able to add a little more to that after the next several hours of light rain.

This rain is being produced by a nice surface low in the Northern Gulf. We will see this Low rotate into Northern Alabama by tomorrow morning. So tomorrow's forecast will be cloudy, but there is a slight possibility we could have light drizzle left behind during the day.

Tuesday, January 12, 2010

El Nino Cycle Update

I just reviewed the latest El Nino Southern Oscillation update from NOAA's Climate Prediction Center. A few details summarize what is happening in our strong El Nino pattern.

-Sea Surface temperatures (SST) are 1.0C - 3.0C above-average across much of the central and east-central equatorial Pacific.
-During the last 30 days, equatorial SST anomalies have decreased in small areas across the eastern Pacific.
-Based on current observations and dynamical model forecasts, El Nino is expected to continue at least into the Northern Hemisphere spring 2010.

What does this mean for us?
El Nino pattern typicals allows Mississippi to be cooler and wetter. Evidence of the El Nino pattern can already be noticed from the wet December and cold start to January.

Sunday, January 10, 2010

Sunday Night's Discussion

A typical trend might happen this week. The models might be moving the cold air out too quickly. Actually, model output statistics has lowered a couple of degrees through midweek and the end of the week's temperatures. This will have to be watched for a precise numbers forecast, but most of us won't really notice the forecast issue.

But most of us will all notice the sunny and dry week. Precipitation won't come around until Friday and Saturday. Thursday will be a great day to look at wind flow because we will finally have an impressive southwest flow from upper levels to the surface. This will pump increased moisture from our beloved Gulf influence. Then I expect to see a deep upper level trough sweeping across the country and influencing our rain event at the end of the week. I'm drawing in a surface Low moving in late Friday and producing rain into Saturday.

Extended forecast show a shift in closing out the month of January. I'm beginning to lean in the direction that we won't have the opportunity to see extremely cold temperatures again this season. Typically, January is the month we receive cold outbreaks and this month is trending warmer than the 1st half. In other words, the core of the cold air looks to be staying back in Canada for the average of the 2nd half of January, but I'm not saying we will have above normal temperatures. I still believe we could be at and near climatology to close out the month.

On a personal note: I'm ready for the hot summer days to roll back around. I think the length of this cold outbreak has made me wish for warmer days to come back quicker.

Saturday, January 9, 2010

Cold Air Relief

A temperature this morning of 15 was the coldest we've experienced at WDAM Studios since January 4, 2008. We can also note this long cold stretch can be considered the longest stretch since 1979 in Mississippi.

My main weather story today will include a discussion on the cold weather relief. Many folks are beginning to beg for warmer temperatures after this long week of extremely cold nights. No, we won't have a trip to Jamaica, but we do have warmer temperatures on the way.

The bold arctic air mass will finally exit stage left (east) by Tuesday, and this will help increase upper level temps. Thickness values will also finally increase due to warm air expansion in the atmosphere. A 1031mb high will filter into Mississippi on Wednesday and allow a pull of moisture by Thursday to filter into the region. Of course, this will also eventually evolve into our next chance of rain late in the week, but the majority of the week will be dry since we will be in the recovery phase after an extremely dry period. Also, any lifting mechanism will be relatively absent for the work week forecast.

Friday and Saturday looks like our next chance of rain. Forecast models try to pick up on a large upper level trough rotating through the southwest and gulf coast regions into Saturday. This will be the system to watch as it should be our next rain maker.

Wednesday, January 6, 2010

Mixed Bag....

It looks as if we are set up to receive a mixed bag of sleet, rain, sleet again and maybe snow on your Thursday... in fact, it may actually come in that order. We have a 100 percent chance of precipitation Thursday, but fluctuating temps we keep this from being an all snow event.

While we will start off Thursday morning with in the lower 30s... I expect that we will be in the lower 40s by 9:00 or 10:00 am. However cold air will be surging our direction during the day and we may be back to the mid to lower 30's by 3:00pm.

I have already turned our streaming radar on and we will be updating our website with closings and weather information through out the day.


Warmer Today but Frigid Friday is near

Not much has changed after looking over the most recent outlook for tomorrow's weather event. My thoughts are still the same on the precipitation. It looks like the precip will be in the area from mid-morning to late afternoon, and most of the Pine Belt is on track to see mainly a rain event. Snow flurries and light snow have a chance to be seen in our northern counties, but most of us will experience rain. Some road travel will need to be monitored tomorrow night as leftover water on the ground will freeze.

All week my main concern has never been the precipitation forecast for Thursday but the temperature forecast through Saturday. Yes, today's temperature is slightly warmer in the mid-40's, but the cold front tomorrow will quickly drop overnight temperatures back into the teens. Friday and Saturday night will be in the lower to mid-teens. Also, the high temperature on Friday and Saturday will be near freezing. These temperatures are criteria for deathly cold situations.

We should all be concerned with staying warm and providing for those less fortunate around us during this time. Cold snaps like this event are known as "silent killers" for areas in the south that aren't accustom to such cold weather. Some folks don't have sufficient heating capabilities here in the lower mississippi river valley. Stay safe.

Tuesday, January 5, 2010

Full thoughts on Thursday's Snow Forecast

In my opinion, the bigger story this week are the cold overnight temperatures, but I do realize many of us have to plan for possible hazardous road conditions during Thursday's precipitation.

What precipitation will fall on Thursday?
This morning my thoughts are being better defined around the trending model pattern. Two days ago we definitely knew temps would warm significantly above freezing on Wednesday, but Thursday was still difficult to where the rain/snow line would exist as precipitation moves through.

Now I am getting a better feeling about the positioning of the rain/snow line Thursday morning and into the afternoon. Snow is likely in North Mississippi (Greenwood/Batesville/Tupelo/Starkville) and wintry mix/snow is expected along the I-20 corridor through Jackson and Meridian. Hattiesburg is more in the rain region because I believe the rain/snow line will make it down to Jasper County and fade into Covington, Jones, and Wayne Counties. Light snow should be seen North of Forrest/Lamar counties. Once again, Hattiesburg area should be more concerned with rain and the very cold temperatures Thursday night through Saturday.

The timing on the precipitation for the whole area will be between the morning to early afternoon on Thursday. The temperature will be dropping quickly Thursday afternoon as the cold front passes through, but, fortunately/unfortunately, the precipitation will not be around during the coldest part of the day from late afternoon into the night.

At this point, the only school systems that should be considering closing Thursday encompass the Simpson, Smith, Jasper, Clarke Counties.

Monday, January 4, 2010

Cold like 1996!

Today was cold, but we will experience even colder temperatures at the end of the week. Another strong arctic cold front will drop highs into the upper 20's and lows near 10.

Many folks have been thinking this cold air mass mirrors a system we experienced in 1996. Our data from February 4, 1996, shows a high of 26. Then the morning of February 5th was only 8 degrees!

Friday night will be very cold near 10, which resembles the 8 degree mark in 1996. This afternoon I ran across's forecast on my iPhone for Friday night, and this product says the low will be 19. Nineteen is much warmer than what will really happen. This is because they only spit out numbers from a computer, but we have different numbers because computers can't comprehend major arctic outbreaks.

Arctic Air Headed Our Way !!!

We are in for a cold next few days but then the BIG BLAST of Arctic air arrives sometimes Thursday. Please be prepared for this in advance! Snow is possible late Wednesday into Thursday. Not sure on accumulations yet but in any event the main weather story is the brutal air that arrives with the snow. Low temps by Friday night into early Saturday may be in the 10 degree range ! Take precautions NOW ! More on this developing situation later. Rex

Sunday, January 3, 2010

Possible Snow Accumulation

This link provides the latest GFS computer model look at snowfall accumulation.
It's only a model!

But it shows where the computers are thinking at this point for Thursday's forecast. South Mississippi is only looking at snow flurries while Central MS could see an inch to 2" of accumulated snowfall. I believe the coverage will be greater than what this image shows, but I can agree that flurries and the low end of total accumulation compared to others in the whole state can be expected.

...much can change though...


Tonight I'm struggling to figure out the various ways to describe our cold forecast. It's simply cold. Four out of the next six nights I'm forecasting to be in the teens. Also, it seems plausible to have two days this week topping out in the 30's. Then we have to talk about the chance for wintry precipitation on Thursday's strong cold front.

An upper level trough will continue to rotate through the Southeast and continue to deliver a strong shot of cold air. This will allow a very chilly day tomorrow with the high barely touching 40 degrees, which means the majority of the day will be below 40! December 22, 2008, was the last day we spent below 40 degrees.

After Monday, the temperatures will rebound only a few degrees on Tuesday and Wednesday. Wednesday looks to be the warmest day of the work week with a high in the upper 40's, but this will change quickly with an even stronger blast of cold air. Thursday will be highlighted in the forecast as the only day for likely precipitation. It's still difficult to specify the rain/snow line when precipitation will be coming down.

I've lowered Thursday's high into the upper 30's considering the cloud cover and cold start to the day. I'm expecting the temperature to struggle with the falling precipitation and moving cold front.

Will it snow on Thursday?
The cold air behind the front will definitely produce snow to our northwest, but it's difficult to depict a concrete situation for southeast Mississippi. The upper level sounding will all be below freezing till you get down to about 1,700 feet above the ground. The temperature from 1,700' should only rise a few degrees above freezing. So what does this mean? If this setup became true then we would see freezing rain/wintry mix changing to light snow. Most models at this point aren't bringing the best accumulating snow to South Mississippi, but any slight movements (50-100 miles) in the system's location could cause major changes in the forecast.

Saturday, January 2, 2010

Cold Forecast Discussion

My weather story revolves around the cold temperatures. This time last year we had temps well into the 70's, but 2010 has started with a significant cold air mass in the lower Mississippi River Valley. Today, high temps in the 40's will dominate the 7Day forecast.

Also, tonight's low temperature in the mid 20's will be the first of many nights below freezing. We could easily see temps in the upper teens a few times during the week.

The biggest story most people will be interested in will be the possible snow forecast on Thursday. A large cold front will drop into the Leaf River Valley thursday afternoon producing precipitation. Light rain will be the main emphasis ahead of the front, but the rain can easily change to light snow/flurries late in the night. My wording will keep with rain changing to flurries and light snow until something dramatically changes. Precipitation is likely but it's difficult to distinguish the timing of the rain/snow line at this point.

Friday, January 1, 2010

Happy New Year 20-10!

Happy New Year!
After an above normal rainy December, January will start off with below normal temperatures.

December totaled a record breaking monthly rainfall. Here at the station we ended up getting 15.71" and Bobby Chain Airport recorded 17.34". Our totals in the Pine Belt were still dramatically less than the incredible 25.92" received at New Orleans Airport.

Now in January we take our first steps into the coldest part of the year, and upper level temps going into the 7 day forecast portray this fact. Models show Monday's 850 millibar temps dropping to a chilly 17 degrees so I've also dropped Monday night's forecast into the upper teens. This will also help maintain daytime highs in the mid to upper 40's for the majority of the 7Days.

With temps so cold will we see any snow?
Like I discussed in our previous blog post, our positioning within the next few systems in the coming days will put us within about a 200 mile distance from the rain/snow line. With this in mind, snowfall is not out of the question as we look into the upcoming month. Our next chance for snow will be Thursday night, but nothing is definite 7 days away with a snow forecast. I'm keeping the forecast mainly rain at this point. This weekend I will have better details on Thursday's rain/snow event.