Mainly Sunny, Dry Days Ahead!

By Jay Grymes & Steve Caparotta

Boy, oh boy ... the sun never looked so good!

Skies should stay mostly clear overnight and into the morning.  It gets cold again though, with lows dropping into the low 30°s for metro BR.  That means a light freeze for many communities along and north of the I-10/12 corridor, but not a big deal in terms of temperatures or freeze durations.

The forecast stays mainly sunny for Friday and right through the weekend – that’s got to be much welcomed news for just about everyone!  And we’ll warm it up a bit too, with highs in the upper 50°s for Friday and into the 60°s for the weekend.

Obviously the dry weather is good news for folks along our area rivers and bayous, but we all could benefit from a good run of dry weather given the region’s waterlogged backyards, fields and pastures.  And Mother Nature cooperates: not only do we stay rain-free through the coming weekend, but the extended outlook keeps us mainly dry right through next week and into next weekend, at least!

We will have another front pass through the state on Sunday, but it will be a dry Canadian front.  We’ll feel a little dip in temps on the backside of the front with the cooler air-mass in place, but the frontal passage will do little more than generate a few clouds for south Louisiana.

Now, for you trivia buffs, let’s take another look at the rainfall thus far for January.  Metro Airport is reporting 13.81”, with January-to-date reports from across the WAFB region ranging from 10” to 18”!  And to our west, in Eunice, they’re reporting a whopping 20.29” already this month - - the equivalent of 4 month’s worth of normal rainfall!

For Baton Rouge (Metro AP), the 13.81” is the largest monthly total since December 2009 (14.86”), and already ranks as the second “wettest” January on record (data back to 1888), topped only by 14.94” during January 1998.  Although our forecast keeps us dry through the next seven days, that January 1998 all-time record might still be in jeopardy.

A look at all months back to 1888 -- that’s 125 years, or 1500 months – ranks our January 2013 rains already at #18 for all-time high monthly totals, in the top 2% of all months!  When we look at it in those terms, it’s somewhat surprising that the flood damage hasn’t been worse.

And by the way, what was the “wettest” month ever for Baton Rouge based on these records?  You probably remember June 2001’s Tropical Storm Allison, which helped take that month’s total to 21.36”.  The only other over-20” month in the time series was back on November 1929.

Snow Tonight/Thursday AM?

I woke up to this morning to a few questions on social media asking about snow being mentioned in the forecast by some outlets. I was a bit surprised since we had downplayed the threat Tuesday night, but an examination of the latest computer guidance in this morning shows why that magical 'snow' word is being tossed around.

The prospects for any wintry weather are tied to a fairly potent upper-level low forecast to move across the area late tonight into Thursday morning.

NAM (computer model) forecast valid at 3 AM on Thursday. An upper-level low is noted moving across central/northern Louisiana.

The upper-level low is important for 2 reasons: 1) it generates 'lift' that can lead to the development of clouds/precipitation, and 2) these upper-lows carry pockets of cold air aloft in the atmosphere necessary for frozen precipitation.

Most guidance shows that the atmospheric profile (temperatures from near the surface to several thousand feet above ground) will be plenty cold enough late tonight to support wintry precipitation, primarily in the form of snowfall. The big question remaining is: will there be enough moisture left?

Yesterday, our computer guidance was unanimous and adamant that necessary moisture would exit the region well before the arrival of the upper-low. The big change with this morning's guidance is that much of it now hints at just enough moisture lingering to squeeze out some very light precipitation late tonight.

Our RPM model now generates some light snow near the state line into SW Mississippi near/after midnight tonight...

RPM forecast valid at 2 AM Thursday. Snow is represented by shades of blue and white. A wintry mix is represented by the pink shading.

RPM forecast of snowfall potential through Noon on Thursday. 

Here's the key...while the odds of a little wintry precip/snow may have increased a bit this morning, we still believe anything that falls should be quite light. The greatest chances for any wintry precipitation appear to be near the LA/MS state line northward into SW Mississippi. Even here, significant accumulations appear unlikely, although it's possible a little snow could briefly accumulate on trees/grass and elevated surfaces.

Here's another look at snow potential...the graph below shows that the NAM (computer model) is forecasting about 1/3 inch of snow at McComb, while the GFS only generates about 1/10 inch.

The same plot for Baton Rouge shows the models have no snow accumulating in the Capital City, although I wouldn't completely rule out some flurries or very light snow late tonight.

Bottom line: even if anything falls tonight...and it's still a big 'IF'...significant accumulations are not expected. Of course, Jay and I will have the latest on 9News at 5 & 6 this evening.

Rains Finally Diminishing Wednesday

By Jay Grymes & Steve Caparotta

Some WAFB neighborhoods saw as much as 0.5” to 1.0” of rain today, adding to the region’s record-approaching January totals, but thankfully these amounts were not so much as to prompt new rises on most area rivers.  We continue to watch water levels show very slow falls along most area waterways, although the lower reaches of the Amite have remained essentially “flat” through most of the day.

The weather story now shifts from rain to cold.  Today was yet another rather disagreeable day weather-wise, with highs for some of the northern WAFB communities barely making it into the 40°s!  Add in the damp air and the northerly breezes and it certainly felt much colder.

We’ll keep on-and-off passing, mainly-light, showers in the forecast through tonight and Wednesday morning, with the rains coming to an end for most of us by or before mid-day Wednesday.  Some could even see some peaks of sunshine late Wednesday afternoon, with skies clearing across the region from Wednesday evening into early Thursday.

Along with that clearing will come the main shot of a Canadian air mass, with temps dipping below freezing for many WAFB communities by Thursday morning.  You may have heard about some potential for “winter precipitation” this week, especially for northern portions of the WAFB viewing area.  The air will certainly be cold enough by late Wednesday night into early Thursday, but we think that the moisture will get out of the area well before the freezing temps arrive, eliminating any serious potential for snow, sleet or freezing rain.

Plan on sunshine for Thursday, Friday and Saturday. 

After a freezing wake-up, temps will climb into the mid 50°s under the sunshine for Thursday. Much of metro Baton Rouge will drop back into the low 30°s for Friday morning, with light freezes possible for neighborhoods near and north of the I-10/12 corridor, but afternoon readings should return to the mid to upper 50°s for Friday afternoon.

The weekend is looking good, with highs back into the 60°s and a continued and much-welcomed dry-out.  And the forecasts show that most, if not all, area rivers should be back below flood stage over the weekend.

Flash Flood Watch Into Thursday

By Jay Grymes & Steve Caparotta

As of 5PM, much of the Baton Rouge metro area had already received upwards of one-half-inch of rain, with generally light-but-steady rains continuing to fall over the ‘Red Stick.’  The rain through the overnight is expected to remain fairly constant as well, and falling at slightly higher rates than we’ve seen this afternoon.

A FLASH FLOOD WATCH has been in effect for areas west of the Atchafalaya Basin, and a new FLASH FLOOD WATCH -- which includes most of the WAFB viewing area - - was issued this afternoon and remains in effect until 6PM Thursday.

We’re still awaiting the passage of the anticipated warm front that we described yesterday.  That likely occurs tomorrow morning, which means rain likely not only through the night but through the morning hours too.  Looks like a very wet morning commute.  Lows tonight likely remain in the 60°s for many of us, with highs on Wednesday climbing into the 70°s as we move into the “warm sector” (the south side of the warm front).

While we think there will be breaks in the rain during Wednesday afternoon, we still expect showers and possibly a few t-storms through the day.  As we head into Wednesday night and early Thursday, our attention will turn to the west with the approach of a cold front.

As we noted yesterday, the advancing cold front does not look like it will be an especially fast-moving boundary, so the timing through Thursday is still a bit in question.  For now, we’ll call for scattered showers and t-storms Wednesday night, with “showers and t-storms likely” for Thursday morning.  For the time being, it looks like rains will slowly end from west-to-east during the afternoon and evening.

The NWS Storm Prediction Center still has most of the viewing area under a “SLIGHT RISK” for severe weather for Wednesday into Thursday morning. The primary threat will come as a cool front approaches from the west on Thursday.

Models continue to show differences, but it appears as though 2” to 4” for much of the WAFB viewing area between now and Thursday is very reasonable, with locally higher totals.  Not only is this range sufficient to warrant a WATCH, but we’ll need to monitor rainfall trends closely: 4” of rain could become problematic for area rivers.

Projected rainfall totals through Thursday afternoon from the RPM model (left) and GFS model (right). The RPM seems to be running a bit high, but isolated rain totals of 6" to 8" are possible.

It looks like we’ll get a short reprieve from the rains on Friday, but we’ve got our next frontal system moving into the area late Saturday into Sunday, with the system potentially stalling along the coast, keeping rains in the forecast through the early part of next week.

Wet Weather Returning...

By Jay Grymes & Steve Caparotta

Given our rather cool, cloudy and damp start to 2013, today’s sunshine was a welcomed sight!  But you’ve probably already noticed that today’s blue skies were short-lived: the clouds are moving in from the west and will continue to “thicken” into the night.

Yep -- keep the umbrella within reach, just about all week long!

We’ll start off Tuesday under the clouds but dry ... and not quite as cool as Monday’s start for the kids at the morning bus-stop with sunrise temps on Tuesday in the mid 40°s around metro Baton Rouge.  Tuesday afternoon will be a bit warmer as well, with highs expected to reach the upper 60°s for many WAFB neighborhoods.  But during the afternoon, especially the latter half of the afternoon, we expect rains to start moving in from the southwest and west.  It looks like scattered showers and maybe a few rumbles of thunder for the Tuesday evening commute.

By Tuesday night into the early hours Wednesday, just about everyone gets wet again.  But the warm-up continues as a warm front lifts northward from the Gulf. 

An upper-level storm system over northern Mexico will help strengthen a developing surface low pressure system over south Texas.  The warm front that slides through the viewing area from late Tuesday into early Wednesday will be tied to that Texas low ... as will a trailing cold front.

But this Texas storm complex will be a bit of a slow-mover, with the low still to our west late Wednesday into the early hours Thursday.  We will be in the “warm sector” ahead of the system, and that should help take highs on Wednesday into the 70°s.  We’re thinking that the rains will taper off a bit by Wednesday afternoon and into the evening hours, with much of the area remaining mainly dry into early Thursday.

By Thursday morning, with the surface low to our northwest and moving north, the forecast calls for the system’s cold front to begin its advance to the east.  This set-up over the next couple of days offers the potential for some energetic storms, prompting the NWS Storm Prediction Center to post a “Slight Risk” for severe weather across most of the WAFB viewing area from mid to late Wednesday into early Thursday.  (We’ll have to see if that threat is extended into the middle of the day on Thursday.)

With this slow-moving system and a very “juicy” atmosphere, the bigger threat may well be the potential for a serious rain event over the coming days.  While it looks like the heaviest regional rains will stay to the west of the Atchafalaya Basin, we can’t rule out some 2” to 3” rains across our viewing area, with localized totals possibly going even higher.  Thankfully, most of the area rivers and bayous are in decent shape for handling a big rain event as long as areal averages don’t get too large!

 Most of us will get another brief break from the rains on Friday, but our current weekend outlook has rain returning, especially for Sunday!

Gloomy Weather Returns Saturday

Friday got off a rather chilly start, but just about all of our official reporting stations stayed just above freezing. Metro Airport saw a low temperature of 33° just after sunrise. And even with a decent amount of sunshine at times this afternoon, highs only reached the mid 50°s for most of us.

 Gloomy weather returns as we move into the first weekend of 2013. Skies will likely become overcast during the overnight and we can’t rule out a few sprinkles. We then look for cloudy skies, cool temps and scattered showers during the day on Saturday. Rains shouldn’t be that widespread and will for the most part be rather light, but any showers will just add to the unpleasant feel on Saturday. The clouds and showers will again keep highs in the mid 50°s for most.

 A few showers could linger into Sunday morning, but we expect some improvement by the afternoon – including the possibility of some sunshine before the day is up. We’ll then enjoy a rather nice winter day on Monday before things yet again start to go downhill.

An approaching storm system will bring a return of clouds and the chance of a few showers by Tuesday. After that, there are big question marks both on the timing of our most significant rains and the degree of cool-down we see, if any at all.

Right now, we’re leaning towards the heaviest rains arriving on Wednesday and possibly lingering into a portion of Thursday. There is also some indication of a possible severe weather threat, but we’ll get a better assessment of that as the event gets closer. The same model that points toward a slower arrival of rains also keeps temps mild during the latter half of the week, so that’s what we’ll go with for now.

Have a great weekend!

Hoping for a Little Sun on Thursday!

Do you have a case of the ‘winter blues’? Yet another dreary and chilly day may have left you feeling a bit sluggish, with temps stuck in the 40°s, along with off-and-on drizzle and light rain. There have even been isolated reports of very light sleet today, and we can’t rule that out for this evening, but anything falling in a frozen form would be VERY light and there are no concerns with accumulation.

Clouds and occasional bouts of light rain/drizzle will continue into the overnight hours as Pacific moisture continues to stream up-and-over a shallow mass of cold air at the surface (something meteorologists refer to as ‘overrunning’). However, strengthening high pressure to our north is expected to shunt most of the moisture offshore by daybreak on Thursday.

The big question then becomes, will we see any sunshine? It appears to be a close call, with better chances of some sun north of the interstates and higher likelihood of remaining overcast closer to the coast. We’ll call it mostly cloudy for Thursday, although some areas to the north will likely see more in the way of sunshine.

Even if the sun does make an appearance in your neighborhood on Thursday, it looks as though clouds will quickly return by Friday as our next storm system approaches from the west. We’ll keep the Friday forecast dry, but scattered showers return to the area over the weekend. Right now, I’ve got rain chances posted at 30% for Saturday, but it’s possible I may have to look at increasing those a bit over the next couple of days.

Cool weather stays with us through the weekend, with a modest warm-up expected into next week.