Tuesday, December 30, 2014

Cool & Dry for New Year's Eve

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- skies continue to clear tonight with lows falling into the 30°s
- sunshine but staying cool for Wednesday afternoon
- clouds slowly return New Year’s Eve evening, 40° in Baton Rouge near midnight

As expected, the day began with a thick overcast.  What was a surprise was just how persistent that clouds would be through the day.  Cloudy skies and a north wind through the day kept things much cooler than we had anticipated -- many WAFB neighborhoods never got out of the 40°s! 

We will see slow thinning and gradual clearing this evening.  Clearing continues overnight, with the cold-and-dry Canadian air mass finally taking full control.  Thankfully, we won’t get a full-on Arctic blast this go-around, but look for lows to drop into the mid 30°s for both Wednesday and Thursday mornings.    Light freezes will be possible to the north and east of metro Baton Rouge on both mornings, although the Capital City should remain above freezing.

We’re expecting mainly sunny skies through the daytime hours for Wednesday-- New Year’s Eve.  Highs on Wednesday will be cool-ish -- mid to upper 50°s for most.  The fair skies don’t last long, however.  Heading into Wednesday evening, expect a slow return of clouds, with partly to mostly cloudy skies at midnight as the Red Stick drops in downtown’s Town Square.  Temperatures at midnight will be around 40°, but it stays dry for the nighttime fun.  A light NE wind will add a little Louisiana winter ‘feel’ to the late night air, with a windchill in the 30°s.  Cold? Yep, but not miserably cold.  Just be sure to dress for it if you plan to spend much time outdoors.

The weather picture for Thursday and into the weekend remains relatively unchanged from yesterday. 

After a Thursday morning start in the 30°s under mostly cloudy skies, we’re thinking highs in the 50°s again for the afternoon, with rain chances slowly increasing through the latter half of the day.  By Friday, rain is a sure bet as a low in the western Gulf drifts northward.  The Gulf storm system strengthens (“deepens”) as the low moves into the Bayou State late Friday and early Saturday, with a warm front lifting to our north, putting the WAFB viewing area in the “warm” sector.  That not only means another wet day, but Saturday -- especially the first half of the day -- could be a little stormy at times as we wait for the complex to head east into the Southeastern U.S. later on Saturday and into Sunday. 

It’s still a little too early to confidently assess the severe weather threat for the end of the week -- that’s something we’ll want to watch in the coming days.  For now, a widespread severe weather outbreak appears unlikely.  However, area-wide rain totals of 1.5” to 2.0”, with locally-higher amounts, are possible if not probable, with the heaviest rains occurring Saturday.​

Monday, December 29, 2014

Hoping for Sunshine on Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- stays cool through the rest of 2014 with a welcomed dry-out over the next two days
- chilly but dry for New Year’s Eve festivities
- rain likely for Friday and Saturday 

We’ve had a little bit of everything over the last few days, dominated by “wet.” Since the weekend, most of the WAFB area has seen from 0.5” to 2.0” of rain, with some pockets well above 3.0” -- thankfully, however, the feared deluges and subsequent flood threats failed to materialize. It was awfully muggy for the first half of the weekend but a cold front finally brought a return of winter-like temps.

Now that the front has moved through, 50°s have replaced the 70°s, although we still haven’t been able to get out from under the clouds. So today was a damp, occasionally-drizzly, rather disagreeable day. But there is hope: sun returns to the forecast!

Although the rain is long gone, it’s looking like the clouds will linger through the night and into Tuesday morning. But clearing should be underway by the afternoon, if not sooner, giving us some afternoon sunshine and fair skies by Tuesday evening. Tuesday morning clouds will help insulate us a bit, keeping overnight and early morning temperatures in the 40°s, while the afternoon sunshine will help offset some of the chill of the post-frontal air mass, with Tuesday highs expected in the upper 50°s to around 60° or so.

That same dry continental air mass and fair skies for Tuesday night into Wednesday morning will allow temps to drop into the 30°s for Wednesday morning -- possibly flirting with a freeze along and north of the LA/MS state line. Wednesday afternoon highs should reach the mid 50°s for the Red Stick under fair skies. But clouds will begin a steady return by Wednesday evening -- that’s not necessarily a bad thing since the clouds will slow the evening temperature fall. We’ll stay dry Wednesday evening into early Thursday -- area temperatures around midnight will run in the upper 30°s to low 40°s. For Red Stick Revelry in the heart of BR’s downtown, it may even be a degree or two warmer: certainly not mild, but not bitterly cold -- and more importantly, dry!

It’s down to the low to mid 30°s for many by Thursday’s sunrise, with highs in the 50°s again for Thursday. We’ll also start to slowly re-introduce rain chances through the latter half of the day. By Friday, it’s wet as a low in the western Gulf drifts northward, bringing “overrunning” rains and a warm front into coastal Louisiana. Our current guidance suggests that the Gulf low “tightens up” along the upper Texas Coast, possibly near Sabine Pass, and then marches east along the Louisiana coast on Saturday, making for another wet day before the frontal complex shifts to the east. The rains end on Sunday, with another run of cool days to follow.

Monday, December 22, 2014

Strong to Severe Storms Possible on Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- potential for another round of area fog tonight and early tomorrow
- “marginal” threat for severe weather this evening into early Tuesday
- “slight risk” for severe storms on Tuesday, especially from mid-day into the early evening

The next 24 hours could be rather busy for some residents of the central Gulf Coast as a variety of weather features combine for a potentially stormy Tuesday. The trade-off is that by early Wednesday the weather takes a turn to the “good” and delivers a back-to-back cooperative winter days for Christmas Eve and Christmas Day.

Yes .. we said winter, as Sunday was the Winter Solstice, making today the first ‘full’ day of winter. However, today certainly didn’t have much of a winter feel with highs in the 70°s. A mild and moist air mass over our region promoted fog development earlier today, and the same set-up means another round of fog possible for Tuesday’s start -- if the winds subside enough. At the same time, a warm front moved northward out of the Gulf today and is headed well to our north. The Gulf air behind the warm front will add even more moisture (dew points at 60° or more) to the lower levels which will increase low-level instability. 

We’ve seen a few passing showers today and we’ll keep isolated rains in the evening and late night forecasts too. 

At the upper levels, a deepening trough and southwesterly flow over the central Gulf Coast will work with the moist and unstable air mass, providing lift that could be sufficient to generate a few storms from this later this evening into the early morning. That’s why the NWS Storm Prediction Center (SPC) has just about the entire central Gulf Coast under a “marginal” risk for severe weather through tonight. The set-up isn’t the best for active-to-severe storms, but the SPC sees that enough is in place for one or two strong-to-severe storms to possibly develop somewhere along the Gulf Coast rim. (Remember, “marginal” means that chances are 5% of a severe storm developing within 25 miles of any location -- that’s very low but not a “zero” chance.)

The greater threat for active weather arrives during the day on Tuesday as an approaching cold front provides an even better lifting mechanism to take advantage of the region’s unstable air mass. We’ve got rain chances through the day on Tuesday at 80% or better - - let’s face it, just about everyone gets wet. It won’t be an all-day rain, but we can expect periods of showers and occasional t-storms starting in the morning hours and extending through the afternoon. We’ve got the front moving into the WAFB viewing area from the west sometime close to the evening “dinner hours” and we’ll be on the watch for a developing squall line of storms ahead of the main cold front. 

The severe threat will be mainly in the form of damaging winds although a few tornadoes cannot be excluded. Large hail is also a possibility with the larger thunderstorms. For the WAFB area, the severe threat should end from west to east during the late evening hours on Tuesday, depending on the forward speed of the front.

Once the front passes, the weather will begin to improve, albeit somewhat slowly. It looks like we could still be under a mostly cloudy sky for Wednesday’s sunrise, but the clouds should slowly clear throughout the day. By Wednesday night into Christmas morning, we’re expecting mainly clear skies with a light freeze possible for WAFB’s northern and eastern communities. Christmas day should be mainly sunny but cool, with highs in the 50°s.

We’ll bring a slight chance of showers to the forecast for Friday with scattered showers and a few thunderstorms possible on Saturday. That should clear things out for a nice Sunday.

Friday, December 12, 2014

Good-Looking Weekend Ahead!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- warmer, stays dry through the weekend
- rain likely by the latter half of Monday

Some of you received a little sprinkle early this morning, with a handful of WAFB neighborhoods getting enough to register a couple of hundredths in the raingage (or rain gauge, if you prefer).  Those high clouds through the night carried just enough moisture down from the northwest to “wet the pavement” in some places before sunrise.

As expected, today was a day in-and-out of the clouds.  Those thicker early morning clouds not only dropped a few sprinkles in the area, but served as a warming blanket with sunrise temps in the mid to upper 40°s for many WAFB communities.  Through the day, periods of filtered sunshine between times when the skies were entirely overcast made for a not-so-pretty afternoon, but most of us still managed to get into the mid to upper 60°s during the afternoon.

The clouds stay with us tonight and linger into Saturday morning -- that’s why we’re keeping lows in the mid to upper 40°s for tomorrow’s sunrise.  We had been thinking that the winds would already have swung around, but now it looks like we won’t start getting flow off the Gulf until the latter part of Saturday.  But the morning clouds will thin and we should be under fair skies by mid-day with a mostly sunny afternoon.  That should warm the Red Stick to 70° or more by the mid-afternoon.

Skies will stay mainly clear Saturday evening into Sunday morning, with Baton Rouge area lows again in the mid to upper 40°s.  We’ll start Sunday under fair skies, going to partly cloudy by the mid to late afternoon with highs into the low 70°s for most WAFB neighborhoods.

Procrastinating shoppers will NOT be able to blame Mother Nature and the weather this weekend!

Finally, rain returns to the forecast on Monday as a cold front out of the Southern Plains moves into NW Louisiana on Monday morning and crosses the state through the day.  Unfortunately, many of you will be disappointed with the rain totals.  The early guidance is suggesting that most of us will receive less than 0.5” the way things look now, with many WAFB neighborhoods only getting 0.1” to 0.2” -- certainly not “drought denting” numbers.

The weather settles down by Tuesday morning, with moderately cooler air taking charge.  Our forecast is mainly dry through the mid-week, with our next chance for meaningful rain on Friday.

Wednesday, December 10, 2014

Cool Again for Thursday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- another chilly wake-up on Thursday
- a little warmer for Thursday and Friday afternoons
- upper 60°s to around 70° by the weekend

The forecast for the next few days remains essentially unchanged: another round or two of chilly starts for Thursday and Friday, with morning lows in the upper 30°s to low 40°s for most WAFB communities. We’ll go with low 60°s for highs on Thursday and then mid to upper 60°s on Friday. It will be mild for the weekend with highs in the upper 60°s to low 70°s. And there is no rain in the forecast until early next week.

The air maintains a “dry feel” (low humidity) through Thursday, with winds veering to the east and southeast by Friday -- that will increase the Gulf influence on our region, not only adding a little moisture to the air (rising dew point temperatures) but also supporting the warming trend into the weekend.

So shoppers will have a good run of days to make their rounds … and the weather cooperates for those raking leaves and prepping their yards for the winter weeks ahead. The only real problem for some is the lack of rain that has persisted for most of us since the summer.

According to NWS estimates, rainfall since September 1st is averaging between 50% and 75% of normal across most of the WAFB viewing area, with some WAFB communities reporting only about one-third of normal rainfall for that period. What’s more, a large portion of the rain that has fallen in the past 100 days came in fairly large one-day doses. As you know, heavy rains produce greater amounts of run-off and are generally less effective and efficient at recharging soil moisture. A big rain is not a “good soaking” if it comes down too fast.

While the dry fall has been welcomed by some farmers because of good fieldwork and harvesting conditions, it has also led to increased wildfire threats. Pastures and ryegrass could be in better shape too. We’ll have to wait until the official release tomorrow, but we anticipate a further ‘downgrade’ across the viewing area in terms of the Weekly Drought Monitor, with expanding areas of moderate drought, especially for areas east and south of Baton Rouge.

So when can we expect some rain? 

We still see the next rainmaker arriving on Monday, possibly lingering into early Tuesday. If you are hoping for one of those “good soakers” we mentioned above … well, this one is looking less and less likely to deliver what we thought a day or two ago. We aren’t giving up hope just yet, but it’s currently looking like the main storm energy will stay to our north: good news in that it means a low severe-weather threat on Monday, but disappointing in that the rainfall projections for Monday/Tuesday are coming in at under one-half inch.

Of course, all that can change between now and the weekend, so we’ll remain hopeful that Monday’s frontal passage will be more productive rain-wise, yet without the severe threat.

Tuesday, December 9, 2014

Cooler on Wednesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- mornings in the 30°s and cooler afternoons for Wednesday & Thursday
- warming temps into the weekend
- stays dry through Sunday

We got a little chillier this morning than expected. As it was, our Tuesday morning forecast of 39° for Baton Rouge was below most of the computer models and the NWS forecast too. However, it wasn’t low enough: the Red Stick dipped to 36° this morning, with mid to upper 30°s over much of the Florida Parishes and into SW Mississippi. There were even some reports of light, early-morning patchy fog for the morning commute.

Other than the patches of light-to-moderate fog, it was a mainly-clear sky start to Tuesday and we stayed that way through the day. Sunshine helped push afternoon highs to 70° or more for some WAFB communities. Skies will stay mainly-clear through this evening and overnight.

A reinforcing dose of dry Canadian air is sliding through the Bayou State and that sets us up for a pair of cooler days for Wednesday and Thursday. Look for afternoon highs in the upper 50°s to low 60°s across the WAFB viewing area under high, cirrus clouds for much of the day then go to partly cloudy skies for Thursday. We’ll stay under a north to northeast flow for both days as well. So which of the two upcoming mornings will be the coldest? 

We’ve noted in the past that it is often the second morning that sees the lowest readings after a continental (Canadian) air mass surge. What may get in the way of this soft rule-of-thumb is the potential for a better cloud deck from Wednesday into Thursday morning. So for now, we call for mid to upper 30°s for Wednesday morning for metro Baton Rouge, with some of our northern viewers potentially getting close to a freeze. Then its upper 30°s for Baton Rouge on Thursday morning with mid 30°s for Thursday’s sunrise along the LA/MS state line.

By Friday, winds will swing around to the east, possibly even to the southeast later in the day ... and that will signal the start of a warming trend. We’re thinking the low to mid 60°s for Friday afternoon, then the upper 60°s for Saturday and up to around 70° or so for Sunday. But throughout the period, we stay dry. (Good news for shoppers but we really could use some rain!)

As mentioned yesterday a large, lumbering storm system currently over the eastern Pacific will move into the West Coast over the coming days. By Sunday, the latest NWS guidance shows double-barreled lows associated with the western upper trough and storm system: one surface low over the upper Mississippi Valley and another low in the Southern Plains. 

The southern low looks like it will be a rainmaker for us on Monday, but the intensity and severe threat remains unclear. Yesterday’s guidance suggested a better potential for strong storms than today’s model runs, but as you well know, Monday is just too far down the road for us to have forecast confidence at this stage. So stay tuned ….

Monday, December 8, 2014

Cool, Dry Through the Week

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- stays cool through the work week
- stays dry right through the upcoming weekend

Our run of November/December mild-to-warm days ended on Saturday with the weekend frontal passage. Now we’re into a run of cooler-than-normal weather that began Sunday. 

We’ve said it many times: during the “cool” months (October thru April), daily temperatures are often above- or below-normal for a large portion of the time. Unlike the summer months, what daily temperatures can be nearly identical day after day, it is not uncommon during the cool months (frontal periods) with fewer than half of all days being near-normal in terms of temperatures. We’re either positioned to the south of the front, making for warm days … or to the north of the boundary, giving us a taste of cool, continental or Pacific air. Many of the days that end up “near-normal” are transition days as we see-saw from warm-to-cool (or vice versa).

Normal lows for most of our viewing area at this time of year are in the low to mid 40°s while highs are generally in the mid 60°s. Many WAFB communities dipped into the upper 30°s this morning, although we did warm into the mid and upper 60°s under sunny skies for the afternoon. We’re calling for a “repeat” for Tuesday: upper 30°s to around 40° for Baton Rouge’s Tuesday morning low with mid to upper 60°s under sunshine once again. After that, we’ll cool things down a bit as a reinforcing dose of Canadian air makes its way to the Gulf Coast overnight Tuesday into early Wednesday.

That means morning lows in the upper 30°s for the Red Stick on Wednesday, Thursday and possibly even Friday mornings. We’re not anticipating any freezes for metro BR, but some WAFB viewers north and east of the Capital City -- especially along and north of the LA/MS state line -- could get close. Our forecast calls for highs in the upper 50°s to around 60° for Wednesday and Thursday, with low 60°s for highs on Friday. 

The forecast also says leave the umbrellas at home through the weekend -- good news for holiday shoppers! 

While we can expect a northerly to easterly low-level flow through mid-week, winds will come around to a more southeasterly direction toward week’s end. That means milder air off the Gulf as we climb back into the low 60°s for Friday afternoon then into the upper 60°s to around 70° for the weekend.

In the extended range, guidance is highlighting a developing storm system located over the Southern Plains on Sunday, making for “rain likely” by Monday as the system marches east. It is too early to tell right now, but Monday could prove to be a stormy day: we’ll get a better bead on any severe threat in the coming days.

Friday, December 5, 2014

Waiting on the Weekend Cool Front

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- another round of morning fog for Saturday
- cool front arrives Saturday afternoon/evening

The fog this morning didn’t get quite as dense or widespread as we had feared: great news for the Friday morning commute. But you likely noticed the warmth today -- in fact, today’s high clipped the 80°s for some neighborhoods. For Metro Airport (BTR), today was the third 80°+ over the last six days. Today’s 82° is the warmest of the lot, and just 2° shy of the daily record, which happened to be set last year.

So with this warmth (and humidity), lots of people are looking for a change to something a bit more normal, if not downright wintry. We’ve got a weak cool front sliding through the Bayou State on Saturday: that will bring a modest rain chance to the region through the day and also deliver a cooler and less-humid air mass over the weekend.

But before the “cool down,” we’ve got to get through Saturday. As we’ve seen for the past several mornings, fog will once again be a concern for the overnight and early morning hours. As of 3:30pm, the NWS Office in Lake Charles (NWS/LCH) had already posted a DENSE FOG ADVISORY (DFA) for areas along and west of the Atchafalaya Basin. The NWS/LCH DFA will be in effect from midnight until 10:00am on Saturday.

The NWS Office in Slidell (NWS/LIX) has yet to follow suit with a DFA for their service region as of 4:00pm. They still may issue one later this evening, but for now they are anticipating that the winds and cloud deck will inhibit the formation of widespread dense fog on the east side of the Atchafalaya Basin as well as around metro Baton Rouge and the tidal lakes. We aren’t entirely convinced, as just about all the key factors appear to favor another round of fog tonight and early Saturday, with areas of dense fog (visibility under ¼-mile) likely. However, given that this morning’s fog failed to achieve DFA criteria (even though conditions appeared favorable), we understand the hesitance by NWS/LIX. In either case, if you are planning some late night or early morning travel, be prepared to encounter some dense fog pockets, especially in and around those “usual suspect” locations.

We’ll also toss in some rain chances for Saturday as the weak cool front slides from NW-to-SE across the state. We’re going with spotty-to-isolated rains (less than 20%) for the early to mid morning then raising those chances to around 30% from the late morning into the afternoon. With these limited percentages, it is evident that most stay dry tomorrow. What’s more, even if it does rain over your backyard it won’t amount to much: we’re expecting most rain reports to come in at under one-tenth of an inch.

By Saturday evening, the front should be moving towards the coastal waters, the winds will have already come around earlier in the day, and cooler-and-drier air will be filtering into the region. We’ll call for partly cloudy skies for Saturday night into Sunday morning with no fog threat for Sunday and morning lows down in the 40°s for the northern half of the WAFB viewing area. Skies will continue to slowly clear through the day on Sunday, with an afternoon high in the mid to upper 60°s.

Our extended outlook is a dry one through next Friday under fair to partly-cloudy skies, with daytime highs all week long in the 60°s -- at or slightly below the seasonal norms. Morning starts will be in the 40°s on most days, although a secondary surge of cool, dry Canadian air near mid-week could result in the 30°s for some WAFB communities, but we don’t see anything close to a freeze based on the current guidance.

Enjoy your weekend!