Friday, October 31, 2008

Very Pleasant..Very Nice

If you are looking for a long and deep weather discussion then you better go look at some station's websites in the Northwest US. Our weather story these next handful of days seems very pleasant and very nice. Our friend, "high pressure system," will sit down to our NE over the next few days and really clear our skies out, which will give us a light breeze from the East. Although Sunday night we will see our dewpoint temps increase a tad which will allow our overnight temps to increase as well.

Our next big weather changer looks to be developing in the NW over the weekend. By Monday/Tuesday a well definied trough will be digging across the Rockies, and our impact from this trough should be around Thursday and little into Friday. We are still pretty far out to talk seriously on the timing of this trough, and even the depth of the trough into our region seems very early to nail down anything solid. A few models have shown me only a light shower event, but I must still be aware of the possibility for more of a moderate rainfall event. The one thing we must remember as we enter into the "cool months" is the amount of energy we need for uplift (rain) events. We experience more stable atmospheres in the winter months so we need more vertical uplift and vorticity to to spur on credible rain forecast. All this can be compared to the summer, when our incredible unstable atmosphere only needs a little vorticity and UVVs to create a rain event.

Enjoy your weekend! Be sure to enjoy the beautiful clear nights!

Tuesday, October 28, 2008

A Lesson in Radiational Cooling

Well of course these nights are cold! Why are we experiencing these cold temperatures?

The weather scene is perfect for what we call radiational cooling, but let me first explain what hinders radiational cooling. During the day the ground heats up from absorbing the shortwave radiation from the sun, but the ground doesn't gain any energy once the sun sets. At night the ground emits longwave radiation (energy), but clouds aid in keeping the heat (energy) in the lower levels of the atmosphere. This event will allow the night-time temperature to level-off as oppossed to decreasing dramatically. Now our forecast tonight doesn't involve clouds so nothing will hold back the energy removed from the ground. The clear skies will allow the energy to lost from the low levels of the atmosphere.

Also, high winds will cause the lower level temperature to remain in the lower level. Think of this as a big mixing bowl. The ground's temperature won't be able to leave the lower levels as effieciently as calm winds. Calm winds act as a quick escape for the ground's energy. Our forecast tonight include calm winds.

So tonight will be cold. Break out the winter quilts and turn on the heater because tonight we will experience textbook longwave radiational cooling.

****Also, tomorrow premiers the 1st episode of "The Tanner Cade Hour minus 55 minutes or so" on This is my show for a once-a-week episodes (web only).

Saturday, October 25, 2008

Coldest of the Fall

The title to this blog might become a trend within the remaining days of this Fall season, but our nighttime low temps are always interesting to track this time of year as we slowly transition into winter. This morning we had a low temp of 39, and we haven't had a temperature in the 30s since April 16. So the front that moved through this past Thursday certainly delivered us the low temperature this morning.

On to the forecast:
My thoughts going into our forecast hinge on one factor: another cold front. Yes, we have another cold front already brewing in the Northern Plains. This front will bring us more of a true "Canadian" air mass into the lower MS River Valley, but we will be warming tomorrow ahead of the front.
Right now we have a 1020mb high over the ARLaMiss (just to our west), but this high will quietly move a little south by mid-day tomorrow and bring in a slight push of moisture from the west. The increase in moisture and 850 temps to 12°C will allow us to see temps in the upper 70s across South Mississippi. Although things will continue to change as we move through the day tomorrow. Our biggest change will be ramming down the whole Eastern Corridor of the nation. We, however, will be located in the NVA (negative vorticity advection) zone of the cold front. This really means we will find ourselves on the "left side" of the trough where the convergence and lift are not available for rainfall activity (or even cumulus clouds). Also dewpoint temps will really crash into the upper 20s on Monday Night. Another interesting note should be made about the 1035mb High settling in over the Southern Plains by Tuesday.

So what do I see from this? The front will move through late Sunday night and into early Monday morning, which allows monday afternoons temps to struggle getting into the mid-60s. Most of Miss. will see lower 60s and upper 50s. Basically, our air will be nearly "bone" dry Monday night allowing excellent longwave radiational cooling. Right now I have a forecast low of 36 but you wouldn't have to pull my arm to hard to drop in the lower 30s. Now I must also realize that several folks in our state will potentially see their first frost of the year during this episode.

After Monday things will still be mild. Tuesday looks to be very similar to Monday's forecast, but things will slowly become more "mild" by the middle of the week. Wednesday highs will be the upper 60s before the late-week highs jumping into the lower 70s for Thursday/Friday.

Monday, October 20, 2008

Cool Temps and Rain Forecast

These past few nights we have certainly seen the coolest days of the 2nd half of 2008. Here in Eastabuchie we dropped to 40° last night and Saturday night. Wow! Personally I am excited with the weather we have been experiencing lately. Although I do know some of us would really like to see more rainfall for all of the agricultural professionals out there.

By the way, while we are talking about rainfall, do you have a rain gauge? If so, let me know what you are using for your rain gauge and hopefully we can start communicating with you during rain events. I realize we have several areas in our viewing area that we don't have an accurate precipitation bucket. So feel free to send me a little email at and hopefully we can start working together.

So our forecast is still beautiful for the next couple of days, but we must be looking ahead for the next rain event. Models have really nailed the last few rain forecast but the models are only slightly agreeing on this next rain event. I am definitely seeing a good shot at some rain on Thursday, but the tricky part about this forecast involves Friday's forecast. The WRF model really shows my thoughts on this forecast because I believe we won't see a lot of rain on Friday, but the GFS and European show the system (front) hanging around through most of Friday. Temps are also a big issue with this incoming system. European isn't as cold as the GFS, but I usually expect the GFS to be more aggressive on the advancement of cold air.

I know it might be hard to tell from this picture, but the GFS shows the rain starting Thursday morning.

One more note, this pattern in October is defines one reason why I love weather. I simply love the change of weather from warm and cloudy to cool and clear. My feelings on this probably begin because I enjoy not being able to habitually love and experience one weather scene. Right now I love the fall, but in the spring I will tell you I love the spring.

Sunday, October 12, 2008

Inverted Trough?

Inverted trough? Yes. The clouds and very very light drizzle in our region are due to the influence of an inverted trough. The general definition of inverted would refer to a system that isn't normal or rare. We usually see troughs move from West to East across the country, but we are seeing a small trough (shortwave) move from East to West in the SE'stern U.S. This is very unique and has caused MOS and other models to miss the forecast for a few runs, but I feel like most meteorologist are starting to grasp the whole scenario very well. We saw high temps today only in the mid-70s and we actually recorded 0.01" of rain here at the station. I know a few of us here in the PIB did experience very light drizzle, which didn't accumulate into much precip.

My forecast has this inverted trough moving out of the way by early Tuesday morning, which will allow more sunshine on Tuesday and Wednesday. The next big weather factor comes into our forecast on Thurdsay/Friday as we will begin to see the influence of a cold front. This front shouldn't cause to much rain, but temps will decrease a little bit.

Long Range:
By Saturday and into the next week I expect a major Ridge/Trough pattern to lace itself across the nation. With a ridge developed over the Western U.S. we will see the impact of a Trough sitting/stalling in the Eastern Conus of the U.States. For us we will experience cooler temps and only a small chance of rain through next week.

Wednesday, October 8, 2008

AB Day: Absolutely Beautiful

This was a beautiful day. After the front moved through Hattiesburg/Laurel at 5am this morning our dewpoint temps dropped into the 50s allowing a very pleasant sunrise and rest of the day. At PIB Airport we never saw a reading higher than 73°, which is about 9° below our average high temperature for this time of year. Wow! I'll take it.

And for the remainder of the week our fair weather friend, a high pressure system, moves into the Southeast US. This is good news for those wanting to enjoy a weekend outside. Although our temperatures will definitely be more seasonable by Friday with highs in the lower 80s and up to about 84/85.
My eye is caught on our next major front. The GFS, which often moves fronts too far south too quickly, has backed off a bit on the intensity for us, but we will see some influence of this front by Sunday or Monday. More moisture will be able to filter back into Mississippi by Sunday. After we see an increase in moisture I'll be waiting around for the front to move through. Right now the European Model shows 850 temps starting to lower by Wednesday morning, but the Canadian Model's spaghetti plot isn't very confident in the exact placement of the trough by Mid-week. Tuesday through Thursday seems to be my range of days for my forecast of frontal movement, but many things are still "up in the air."

Right now my best guess looks more at the European with a Wednesday influence of the front, and rainfall will probably fall along the same day. No matter what actually happens, I'm banking on a front moving through the Pine Belt by Thursday afternoon.

Tuesday, October 7, 2008

Rain far

As of 5pm:

WDAMTV: 0.29"
Pine Belt Regional: 0.20"
Bobby L. Chain (Hatt.): **0.01"(not quality controlled)
Jackson Int. Airport: 0.23"
McComb Pike County: 0.03"
Meridian Key Field: 0.59"
Pascagoula (Lott Int. Arp): 0.02"
Gulport-Biloxi Arpt: 0.46"
Hammond, LA: 0.12"

Just raining...

Today explains why I love weather.  We go two weeks without rain and then we suddenly have heavy rain showers with tons of moisture in the air. changes.

My award for the day goes out to the WRF model which has depicted this rain event very accurately ( so far).  My thoughts about today's rain rolled very close to WRF's forecast, and I am definitely thrilled to see the model come through.   We saw a good shot of rain in Hattiesburg this morning before a few hours of muggy sunshine.  In fact, when the skies cleared late-morning, I knew our instability would really drop out.  Heating from the sun and tons of moisture certainly allows rain to pop up fast.  

I'm watching a rather large cell impact southern Lamar county...Hopefully later I can find some rain totals.  As one caller from Rock Hill said, "It is coming down in sheets."

The rain won't be over this afternoon.  I do expect to see bands of rain move through into the late-night hours.  

Monday, October 6, 2008

Back in the Saddle again

Well our big story this week in the weather center is our forecast for rain!  Yes, we have a rain forecast.  It has been more than 2 weeks since we have seen a drop of rain, but in fact today we actually have seen plenty of rain for Stone County and parts of Forrest/Lamar/Marion counties.  A front is making headway through the Oklahoma/Arkansas region today and is expected to push through here on Tuesday.  Although Wednesday we still might see some lingering showers and even Thursday might see a drop or two.  

One interesting note about this event is the thunderstorm activity.  Heavy rain is expected tomorrow from about 8am till mid-day (then on and off throughout the rest of the day), but we will definitely see some lightening mixed in with the rain.  I have only seen a few wind damage reports from today's activity in the Ozarks, but I know we could still see some thunder and lightening.  

Wow do we need the rain.  I think I simply excited to know we are finally starting to get into the mix of our usual Fall-like Fronts pushing through.  After this front tomorrow, we will see another major front push through next Sunday/Monday.  More to come later. 

Some new updates: 
Tropical Storm Marco was just named off the far south shore of Mexico.  The 13th named storm of the 2008 season doesn't seem like a major threat to the Continental U.S. as it will meander around Central America for awhile.