Wednesday, May 27, 2015

You Guessed It...More Rain Ahead

By Jay Grymes & Steve Caparotta

May 20th WAFB First Alert Quickcast:
- scattered rains are back for Thursday, Friday and the weekend

The weather turned busy, bumpy and occasionally rough for some WAFB communities earlier today, especially to the south of metro Baton Rouge.  A squall line marched from Texas across Louisiana through the morning hours, delivering a series of severe t-storms and producing pockets of wind damage on its way by. 

Fortunately the storms weakened somewhat before arriving in metro Baton Rouge and most of the northern half of the WAFB viewing area.  Most neighborhoods across the upper half of the viewing area missed out on the damaging winds, large hail and heavy downpours that we feared.  On the other hand, storms south of the greater BR area remained strong to severe, especially over Iberia, lower St. Martin and St. Mary parishes.

The squall line -- labeled an MCS (mesoscale convective system) by weather pros -- was a bit of a surprise.  Weather models often have difficulty with these kinds of features and often don’t do very good jobs of anticipating their development nor direction of travel.  The line pushed through all but the easternmost sections of the WAFB area before lunchtime, “eating up” most of the atmosphere’s instability (storm energy) for the area as it advanced.  That left us with mainly light rain and showers for the early afternoon, with lingering areas of rain continuing subside through the afternoon.  By 4:00pm, many of us were under the sunshine.

We should remain mainly-dry through the night and into Thursday morning, with a Red Stick morning low around 70°.  The key forecast question for the morning deals with fog: how widespread?  Be ready for areas of fog in the morning and don’t be surprised if the NWS issues a Dense Fog Advisory for some portions of the central Gulf Coast region given the near-steady temperatures and moist air we expect through the night and early morning.

After that, we are essentially locked into a repetitive weather pattern that looks like it holds through the weekend and right into next week: Baton Rouge morning lows around 70° or so, afternoon highs in the upper 80°s, and scattered afternoon showers and t-storms.  Our current forecast keeps daily rain chances at 40% to 50%.

And as you may have already heard, the NOAA tropical experts issued their forecast for the 2015 Hurricane Season this morning -- appropriately using New Orleans as the announcement site.  The official NOAA forecast calls for a 70% likelihood of a “below normal” season in terms of storm numbers.  Their forecast calls for 6 to 11 ‘named’ storms with 3 to 6 of those becoming hurricanes.  Of the hurricanes, the forecast says 0 to 2 ‘majors’.

But just remember, low storms counts in past seasons haven’t necessarily meant a significant drop in landfall threats for Louisiana.  Based on the last 100+ years, Louisiana has roughly a 50-50 chance of at least one ‘named’ storm impacting the state.  Maybe more telling: 1957’s Audrey, 1965’s Betsey and 1992’s Andrew all formed in years with eight or fewer ‘named’ storms.  Are you ready?  Have a gameplan?

Friday, May 22, 2015

Scattered Rains Return This Weekend

By Jay Grymes & Steve Caparotta

May 15th WAFB First Alert Quickcast:

- increasing rain chances through the next 3 days

Friday … finally.  Seems like it was an extra-long work week .. .like someone snuck an extra work day into the week.  But maybe that is because we were waiting on the upcoming Memorial Day weekend: a 3-day break for many and the unofficial kick-off of summer!

But take a moment to remember the purpose of Memorial Day: a day of remembrance for those who have died in service of the United States.  The National Moment of Remembrance, established by Congress, asks Americans, wherever they are at 3 p.m., local time, on Memorial Day, to pause in an act of national unity for a duration of one minute.

No complaining about today’s weather .. and our forecast from last night, with a 30% to 40% chance of rain, proved to be a big bust.  So what happened?  The cool front we showed you last night moved farther south and out over the northern Gulf waters, allowing a more significant “dry out” for today.  Although a couple of spotty showers popped up during the afternoon, the lower humidity (and lower temperatures) made for a nice Friday afternoon, even with the cirrus cloud deck.

So now the question is, “When will the front start its northward retreat?”

We expect it starts moving back in our direction later tonight, but its return will be slow enough that we get another fairly pleasant morning start for Saturday.  It’s won’t be as cool for the Red Stick tomorrow morning as it was this morning - - how about a low of 63° at BR’s Metro Airport and lows in the 50°s near and north of the LA/MS state line - - but we’ll still see some mid to upper 60°s for Saturday’s lows.

Into the afternoon, the warm front will have lifted north of the Capital City, allowing a return of Gulf humidity. That will mean a better chance of rain across the area, but we still think that the majority of neighborhoods will stay dry.  Set rain chances for Saturday afternoon at about 30% or so. 

After that, however, rain chances continue to climb for Sunday and Memorial Day Monday.  We’ll be hopeful for just a 30% to 40% rain chance for Sunday afternoon, but our outlook has “rain likely” for Monday. Expect morning lows in the low 70°s for both Sunday and Monday.  Plan for highs in the upper 80°s for Sunday, with temperatures falling in the afternoon where the rains do fall.  For Monday, with rain chances at 60% to 70%, the cloudy, wet pattern will keep highs in the low 80°s for many of us.  In addition, while it won’t rain all day in your backyard on Monday, rains are likely to be falling somewhere in the viewing area for the better part of the day.

We’ve got “rain likely” for the Tuesday forecast too, with scattered to likely rains for Wednesday.  Heading into Thursday and Friday, we expect to ease back on the rain chances at 30% to 40% or so for both days.

So take advantage of a “drier” pattern for Saturday and Sunday, have a “Plan B” ready for Monday afternoon … and enjoy the weekend. 

Thursday, May 21, 2015

A Little Less Rain on Friday

By Jay Grymes & Steve Caparotta

May 21st WAFB First Alert Quickcast:

- sct’d rains return for Friday, a little quieter on Saturday
- back to scattered showers & storms for Sunday & Memorial Day

A cool front continues to slide southward across the Bayou State this afternoon.  Low-level Gulf moisture, moderately cool air aloft and the approaching cool front are all working together to fire afternoon showers and t-storms.  The first Severe T-Storm Warning of the afternoon was posted just after 2:00pm for Amite and Pike counties -- since then there have been a couple of additional Warnings up near the LA/MS state line and a Flash Flood Warning for parts of Livingston Parish in the mid afternoon. 

To these warnings you can add-in a few strong storms across the WAFB viewing area through the afternoon that produced brief downpours, frequent lightning and probably some pockets of small hail.  Scattered rains are likely to continue into the late afternoon before slowly waning into the evening hours.

We will keep isolated rains in the overnight forecast, trailing off to mainly coastal activity by the early morning.  Scattered showers and storms are expected to return for Friday afternoon.

The cool front mentioned above will ease its way into the coastal waters overnight, then start a slow drift back to the north on Friday.  That set-up should allow for slightly lower dew points (less humid air) to settle over the region tonight, with Friday morning temperatures slipping into the mid to upper 60°s for folks along and north of the I-10/12 corridor.  But with the front slowly retreating northward - - a warm front - - tomorrow and into Saturday, the lower humidity will be short-lived.  Expect a morning start in the upper 60°s for Saturday’s sunrise, then it’s back to morning lows at 70° or more for Sunday and Monday as the Gulf air returns.

We still expect Saturday to be the “driest” of the next four days, with Saturday afternoon rain chances running around 20% to 30%.  As we head into Sunday and Monday, increased instability will mean better rain chances, especially for the afternoons.  Saturday’s lower rain chances also suggest that it will have the warmest afternoon readings over the coming days.  After many communities top out in the low to mid 80°s for Friday, we’re calling for upper 80°s for most WAFB neighborhoods for Saturday.  Plan for mid 80°s on Sunday and Memorial Day (Monday) as we dodge scattered afternoon rains on Sunday and scattered-to-likely rains on Monday.

We’re sticking with scattered to numerous showers and storms for the better part of next week too, with morning lows in the low 70°s for the Capital City and afternoon highs in the mid 80°s through mid-week.  We could see a modest drop in rain chances for the second half of the coming work week, and that will likely be accompanied by a return to upper 80°s for afternoon highs.

Bottom line: it’s about as close to a summer-like pattern that we can be for May.  We recommend that you keep the umbrella within reach for most of the next seven days.

Wednesday, May 20, 2015

Scattered, Mainly Afternoon Storms Persist

By Jay Grymes & Steve Caparotta

May 20th WAFB First Alert Quickcast:

- scattered rains return for Thursday & Friday
- a little “drier” for Saturday?

Once again a round of energetic storms cut through portions of the WAFB viewing area today, delivering some active lightning, brief heavy downpours, and possibly a little hail for portions of Pointe Coupee, West Baton Rouge, East Baton Rouge and the Felicianas during the early afternoon. Those storms continued moving east into Livingston, St. Helena and Tangipahoa parishes while slowly dissipating.  A second cluster of storms over central Acadiana fizzled out during the mid-afternoon as they approached the Atchafalaya Basin.

As of 3:30pm, there had been no warnings issued anywhere in or near the WAFB area, and Doppler activity across the southern parishes continued to wane.  While it is not likely to be entirely dry through the late afternoon and evening, it does look like it will be reasonably quiet -- at least weatherwise -- through the evening commute.

Our forecast for the next couple of days calls for a return of mainly-afternoon showers and t-storms for the next two days: set rain chances at about 50% for Thursday and then 40% for Friday. 

A weak cool front will sag southward through the southern parishes over the next couple of days.  The latest projections for the NWS Weather Prediction Center show the front draped along the coast by Thursday evening and then slipping into the northern Gulf waters by Friday morning.  After that the front is likely to meander near and along the coast before effectively dissipating on Saturday.

That should give us some slight relief from the recent summer-like humidity and allow lows to drop into the 60°s for the Red Stick on Friday and Saturday mornings.  More importantly for many of us, the set-up should deliver a relatively dry Saturday: we’re going with just a 20% rain chance for the day.

By Sunday, however, the warm-and-moist Gulf air mass will have fully recovered ... and that means back to scattered afternoon showers and t-storms for both Sunday and Memorial Day Monday.

Our outlook through the next seven days keeps us out of the 90°s, with highs still hanging in the mid to upper 80°s each day -- about normal for afternoon highs for this time of year.  In fact, some of the wetter days in the upcoming run may be a tad cooler-than-normal, depending on the timing and arrival of afternoon rains.  As for lows, most will be a couple of degrees above normal -- often at 70° or more for the Capital City area -- at least partly due to Gulf humidity maintaining dew points near 70°.

Monday, May 18, 2015

Scattered T-Storms Return on Tuesday

By Jay Grymes & Steve Caparotta

May 18th First Alert Quickcast:
- scattered showers & storms return for Tuesday
- unsettled pattern holds through the work week

While today wasn’t the busiest weather day that we’ve dealt with in the past few weeks, it was far from quiet for many WAFB neighborhoods. Scattered showers and storms -- with some of those storms on the strong side -- have been the local weather story for much of the day. 

A lightning-laden thunderstorm -- likely producing some small hail -- tracked from west-to-east across Iberville, southern Pointe Coupee and WBR parishes around noon time. Not long after, locally-heavy downpours over portions of Iberville, Ascension and Livingston parishes prompted the NWS to issue a Flash Flood Warning for those areas.

However, what most of us experienced today is relatively minor compared to the flooding rains across the northern half of the state! Radar estimates are showing widespread 3” to 5” totals up there with pockets exceeding 8” to 10” of rain in just the past 24 hours. Sadly, one fatality has resulted from the intense rains in the northern parishes.

Our area rains will wind down later this evening, and we will carry spotty showers in the forecast through the overnight and early morning hours. Plan for a muggy start to Tuesday, with sunrise temperatures around 70° for the Capital City. In addition to the spotty wake-up showers, be ready for some patchy fog for Tuesday’s morning commute. 

Our forecast is generally wet for Tuesday afternoon, although rains won’t be as widespread as occurred today: we’re posting rain chances at 50% across the viewing area for tomorrow. Maybe more importantly, we don’t anticipate anything like the downpours observed across northern Louisiana. Most that do get rain tomorrow will likely see totals come in at well under one-half-inch. Expect highs to climb into the upper 80°s Tuesday afternoon before the rains arrive.

We’re easing back on the rain chances for Wednesday to 30%, with scattered showers and t-storms in the forecast for both Thursday and Friday. And again, although isolated larger totals will be possible, most WAFB neighborhoods can expect less than one-inch of rain right through Friday and Saturday.

But expect no relief from the humidity: the “muggies” stay with us as Gulf air will remain in place all week, providing a moist-and-unstable atmosphere to fuel daily rains. Morning lows will trend around 70° to the low 70°s for the Red Stick right through the weekend, while afternoon highs will run in the upper 80°s for most, if not all, days.

An upper-level trough will remain positioned over the western states throughout the week while the central Gulf coast see-saws between weak upper-air ridging and the effects of upper-level southwestern flow around the base and eastern flank of that western trough. When the weak ridging dominates, rain chances will drop off a bit; by contrast, the upper-level southwesterly flow will provide a boost to rain chances when it dominates.

All in all, the WAFB region can expect isolated to scattered mainly-afternoon rains right through the upcoming weekend. With that kind of pattern we recommend that you keep the umbrella nearby although don’t expect to see rain in your neighborhood every day.

Friday, May 15, 2015

Staying Unsettled Through the Weekend

By Jay Grymes & Steve Caparotta

May 15th WAFB First Alert Quickcast:

- scattered to numerous showers and t-storms through the weekend

Today’s first wave of showers and storms moved inland off the Gulf around 10:00am, reaching the Baton Rouge metro area right around the lunch hour.  That band of rains continued to march to the north at about 25-30 mph, reaching the LA/MS state line around 1:45pm.  Doppler radar detected some small hail in a few of the t-storms within the first wave, but none of those storms were deemed ‘severe.’

At the same time, a second, broken band of rains began developing over the coastal parishes and it too headed north.  Both of these bands of rain and storms had a Gulf “sea-breeze” look to them, fueled by a very moist and unstable air mass over the region.

Rains will taper off later this evening, but unlike the past two days, we will keep isolated rains in the overnight forecast.  In fact, for Saturday’s sunrise we’re anticipating spotty showers - - most likely to develop closer to the coast.  The flow off the Gulf continues tonight and through the day on Saturday: our muggy air mass keeps Saturday morning lows in the 70°s for the Capital area, with mostly cloudy skies and pockets of fog for the morning start.

Rains will slowly increase into mid-day and the afternoon on Saturday: we’re calling for a 50% to 60% rain chance through the day.  Much like today, we don’t expect a severe weather outbreak, but one or two storms could be on the strong side, capable of small hail, frequent lightning and locally-heavy downpours.  Most folks should get through the day with one-half inch of rain or less, although a one-inch bull’s eye here and there are certainly possible.

A disturbance over South Texas appears to be slowly headed in our direction and that could enhance Saturday’s rain chances along the Central Gulf Coast.  A look at the models through the next several days shows a  series of upper-level troughs rolling into the U.S. from the Pacific, with upper-level disturbances sliding around the “bottom” of those troughs and riding the upper-level flow into our region. 

Translation: more of the same likely for Sunday and right into next week.  Keep the umbrella within reach!

None of these days are likely to become “all day” rains, but at this point we’re going with rain chances at 50% or better through mid-week, and carrying scattered mainly-afternoon rains in the forecast for the end of the work week too.  The muggy air mass means morning lows at or above 70° for metro Baton Rouge just about all week, with afternoon highs ranging from the mid to upper 80°s for most days, depending on the onset timing of the afternoon rains.

Here’s hoping that you can get some outdoor time this weekend!

Thursday, May 14, 2015

Good Rain Chances into the Weekend

By Jay Grymes & Steve Caparotta

May 14th WAFB First Alert Quickcast:

- rain likely for Friday  
- scattered showers and storms for the weekend

For the second straight day, a large portion of the WAFB viewing area remained dry.  However, there were a few afternoon thunderstorms in our viewing area and while none of them achieved ‘severe’ thresholds they were quite active in terms of lightning. And while the storms were fairly isolated, there was a decent concentration of activity right around the city of Baton Rouge.

Whatever action that does pop-up will subside through the evening and we’ll go dry through the night.  Plan for a partly to mostly cloudy start to Friday, staying dry for the morning commute, but once again with patchy wake-up fog.  It will be a muggy start as well, with sunrise temperatures in the low 70°s for many WAFB communities.

Our recent run of drier weather ends today -- the modest mid-level ridging that has been in place moves east with a mid/upper southwesterly flow taking charge.  The shift in upper-air flow means a series of disturbances to the region beginning with the first tomorrow.  That is why we’ve got rain likely for Friday afternoon and scattered-to-likely rains for Saturday and Sunday too.

With the clouds and rains, some parishes may not even reach the mid 80°s for highs on Friday.  We don’t anticipate a round of severe storms on Friday afternoon, but we could see one or two stronger thunderstorms develop, and a warning or two can’t be entirely ruled out.  It won’t be an all-afternoon rain for everyone, but we do suspect that somebody will be dealing with showers and storms in some part of the viewing area for just about the entire afternoon and into the early evening.

We’ll quiet things down for Friday night into Saturday morning and then do it all over again for Saturday afternoon.  Saturday’s rain coverage may be a tad less widespread than Friday’s, but not much less in terms of areal coverage.  Saturday’s highs will top out in the mid 80°s for most of us.

Unfortunately, Sunday is looking fair wet too: we’re going with 50-50 rain chances for Sunday afternoon with highs in the mid to upper 80°s. 

And the weather outlook stays with scattered showers and storms right through most or all of next week.  A series of upper-air troughs will move from the western U.S. into the Plains, with each driving disturbances through the Gulf region.  At the same time, a steady flow of Gulf moisture into the lower Mississippi will provide the fuel for afternoon rains.

Our suggestion:  keep the umbrella nearby all week long.

Wednesday, May 13, 2015

Fairly Dry Again on Thursday

By Jay Grymes & Steve Caparotta

May 13th WAFB First Alert Quickcast:

- only a few showers today, much the same for Thursday
- higher rain chances for Friday and the weekend

After back-to-back afternoons (Monday & Tuesday) with weather warnings posted for parts of the WAFB area, today’s quieter pattern was welcomed by most.

We started the day under the clouds, and even the afternoon was marked by more clouds than sun.  We didn’t go through the day entirely rain-free, but weak upper-level ridging placed a “cap” on the atmosphere, inhibiting the ability for afternoon clouds to develop vertically.  (It’s the upward growth that allows our morning cumulus clouds to become afternoon thunderstorms.)

What showers that did develop today were located mainly to the west of metro Baton Rouge.  Just about all of today’s showers should be gone by sunset.  Later tonight, like last night, we’ll stay under mostly-cloudy to cloudy skies with Thursday morning lows dipping to the upper 60°s to around 70° for the Baton Rouge metro area. 

Thursday morning’s commute will be a dry one, with a pocket or two of mainly-light fog.  Headed into the afternoon, temperatures will climb into the mid to upper 80°s around the area under a mostly cloudy sky. Today's atmospheric "cap" will be slightly weaker tomorrow, so we'll post rain chances at 20% to maybe 30% for Thursday afternoon -- the majority of WAFB neighborhoods will remain dry once again. Plan for afternoon highs in the mid to upper 80°s.

By Friday, the “cap” should be gone and daytime heating will work with our humid Gulf air to get afternoon showers and storms going again.  In addition, our guidance is showing a fairly healthy disturbance tracking from the west across the lower Mississippi Valley on Friday, adding a big boost to the already unstable air mass.  Right now, it’s not looking like an all-day rain, but showers and t-storms are likely for Friday afternoon.  With the clouds and rains, highs on Friday may only make it into the low to mid 80°s for most of us.

The outlook for the weekend may not be quite as wet as our thinking for Friday, but unsettled weather remains the forecast for both Saturday and Sunday.  Expect scattered afternoon showers and storms for both days with Capital area morning lows in the low 70°s and afternoon highs in the mid 80°s, with a few neighborhoods sneaking up into the upper 80°s.

Headed into next week, we don’t see much in the way of significant changes to the afternoon weather pattern.  Although the NWS Weather Prediction Center (WPC) is currently showing a cool front approaching South Louisiana on Tuesday, the WPC has the front stalling over the southern parishes on Wednesday -- a situation not too different from what we’ve seen the past 24 hours or so. 

That means more of the same: scattered mainly-afternoon showers and t-storms for Monday through Wednesday, with some potential for stronger storms next week as the front draws near.

Tuesday, May 12, 2015

Somewhat Drier on Wednesday

By Jay Grymes & Steve Caparotta

May 12th WAFB First Alert Quickcast:

- a “drier” day for Wednesday
- back to scattered showers and storms for the rest of the week

Today's storms got a late start but action really increased during the late afternoon hours, even prompting a couple of Severe T-Storm Warnings. Through early evening, there have been several reports of mostly small hail and even a report of a couple of downed trees in southern Pointe Coupee Parish.

The showers and storms that did form this afternoon will taper off into the evening as we lose daytime heating.  But clouds will be slow to thin this evening and tonight, so we’re calling for partly to mostly cloudy skies through the night and into Wednesday morning. 

A cool front did sag south across the viewing area and is hanging up right along the coast this afternoon. That front will start a slow retreat to the north later tonight and tomorrow. However, the air stays slightly “drier” (less humid) through the night, allowing early morning minimums to dip into the upper 60°s for Wednesday’s start in the Red Stick.  We don’t expect any wake-up showers but still be ready for some pockets of mainly-light fog for Wednesday’s morning drive.

At the same time, we don’t expect any significant overhead disturbances to pass by as modest upper-level ridging briefly takes hold over the lower Mississippi Valley. With no mechanisms to enhance lift, we should stay relatively dry through Wednesday afternoon … but probably not entirely rain-free.  Even with the slightly less humid air in place, daytime heating will likely be sufficient to kick off at least a couple of afternoon showers on Wednesday.  We’ll go with a 20% rain chance for Wednesday afternoon under a sun/cloud mix with highs in the upper 80°s across most of the viewing area.

As we head into Thursday, the overhead ridging will be shifting east, taking the cap off of the atmosphere and allowing the daytime heating to work with the Gulf air and take us back to scattered afternoon showers and t-storms -- a pattern close to what we would expect in mid-summer.  We’ll go with Thursday rain chances at 30% to 40%.  The weather looks “wetter” for Friday: set rain chances at 50% to 60%, but it’s not a forecast for all-day rains.  As for temperatures, for the rest of the week we can expect morning lows in the upper 60°s to low 70°s and afternoon highs in the mid to upper 80°s for most or all of the WAFB region. 

For the weekend, don’t look for much to change, although we may ease rain chances back to about 30% or so for Sunday.

Monday, May 11, 2015

Keep an Umbrella Handy This Week

By Jay Grymes & Steve Caparotta

May 11th First Alert Quickcast:

- a wetter looking week ahead
- goodbye Ana!

A squall line rolling out ahead of a slowly advancing cold front delivered some strong storms to the northern portion of the WAFB viewing area during the early and mid afternoon hours. The storms came with locally-heavy downpours, frequent cloud-to-ground lightning and indications of hail on the order of 1” or more in diameter for a few spots. The active storms prompted the NWS to issue a handful of Thunderstorm Warnings for more than a half-dozen parishes and counties, in addition to a Tornado Warning for parts of Livingston and Tangipahoa parishes. As of this writing there have been no confirmed touchdowns in our viewing area although we did receive one report from a viewer of a funnel near the Holden area close to Warning time.

The stormy weather has passed and as we head into the evening the rains continue to taper off. We expect most, if not all, of the showers to have ended by the mid to late evening hours with a mainly-dry night ahead. However, we’ll remain under mostly cloudy skies, the air will remain rather muggy, and the damp air and wet ground should allow for the onset of at least some patchy fog. 

Tuesday morning will open with clouds, patchy fog, maybe a spotty shower and a muggy air mass with temperatures near 70° for metro Baton Rouge. We expect mostly cloudy skies through the morning, with rain chances on the rise as we head into mid-day. By the afternoon, we’re calling for a 50% to 60% rain chance across the viewing area. We could see one or two strong storms during the afternoon and can’t exclude the possibility of a Warning, but the threat for severe storms is certainly lower for tomorrow. With the cloud and rains, we’re expecting highs to top out in the mid 80°s for most WAFB neighborhoods.

The cold front that generated today’s squall line will sag southward into the southern parishes but then there for Tuesday and Wednesday before retreating to the north as a warm front. So don’t expect any relief from the humid Gulf air mass that has dominated our weather for the past couple of weeks.

While Tuesday looks rather wet, our forecast for Wednesday is considerably drier, with only a 20% to 30% chance of afternoon rains. For Thursday, we’ll ease the rain chances back to 40%, then return to 50% to 60% for Friday. Plan for mostly-dry but muggy mornings in the upper 60°s to near 70° for metro baton Rouge with patchy morning fog through the week. Highs will hover in the mid to upper 80°s, largely dependent on cloud cover and rain chances.

For the weekend, we’ve got scattered rains currently on the forecast board for Saturday with isolated-to-scattered rains for Sunday, with highs for both days in the upper 80°s.

As for T.D. Ana, the NWS Weather Prediction Center (WPC) has issued its last advisory as of 4:00pm this afternoon. Ana will continue to accelerate to the northeast while skirting the U.S. Mid-Atlantic Coast tonight. The WPC projects that Ana will be absorbed by an advancing cold front -- currently located to Ana’s west -- sometime tomorrow.

Friday, May 8, 2015

Warm, Mainly Dry into Mother's Day

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- only spotty afternoon showers through the weekend
- warm, humid Saturday and Sunday afternoons … feeling like 90°?

For most of the WAFB viewing area, it’s been more than 10 days without significant rain – a dry-out welcomed by many after the locally heavy rains and damaging storms on April 27th.  That same mostly-dry pattern we’ve seen the past many days will continue through the weekend.

Want a little rain?  Not to worry -- we’ve got rain in next week’s forecast, so let’s enjoy the drier pattern through the weekend and especially for Mother’s Day.

Our recent run of weather has been relatively pleasant but you’ve likely noticed the humidity.  That’s not going to change.  With afternoon temperatures sneaking up into the mid to upper 80°s, we’ve been flirting with Heat Index numbers near 90° -- such will be the case for both weekend afternoons.  Expect a little patchy fog for both mornings … just like we’ve seen the past few early mornings.  But the good news is that the weather cooperates for just about everyone on Mother’s Day.

By the way, a big “Thank You!” to all of our area Moms!

Heading into next week, the upper-air pattern will finally support the onset of rains around the area.  In fact, our current forecast calls for scattered rains for just about every day next week.  We’re not anticipating excessive rains, just days with Doppler radar showing lots of returns.

Through much of this past week we were anticipating a cool front making its way into the lower Mississippi Valley early next week.  Our latest guidance now seems to take that out of the outlook.  Instead, our warm-and-moist Gulf air will remain in place and get occasional boosts thanks to passing disturbances.  And no front means no significant drop in temperatures, and maybe more importantly, no drops in the current humidity either.  While our daytime highs may come down a couple of degrees next week, that will be due to the rains and added cloud cover.

The latest on Subtropical Storm Ana shows a system trying to complete a transition to a fully tropical storm.  That appears likely within the next 12 hours or so as convection tries to wrap around the core and the enlarged subtropical wind field continues to contract.  (Remember, subtropical systems tend to be more expansive but a little less energetic than their fully tropical “big brothers.”)

Ana is expected to continue a slow forward motion to the NW to NNW with a likely landfall along the Carolinas coast on Sunday as a “minimal” tropical storm (winds at about 40 mph).  After moving inland, Ana is then expected to get picked up in a strong southwesterly flow, take a hard turn to the northeast and eventually move back out over the western Atlantic.

While ‘she’ is not expected to be an especially destructive storm, Ana will probably make for a wet Mother’s Day weekend for both Carolinas.

For us?  Enjoy the weekend and be careful in the “almost summer” afternoon heat.

Thursday, May 7, 2015

Only Isolated Showers into the Weekend

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

May 7th WAFB First Alert Quickcast:
- isolated showers into the weekend
- Invest 90L has an 80% chance of becoming Ana

Areas of dense fog developed during the morning drive as our muggy Gulf air mass reached saturation -- relative humidity at 100% -- across much of the area. Thankfully, the morning sun dispatched that fog fairly quickly.

After a string of mainly dry days, we saw a bit more action on Doppler radar today, although coverage was still rather limited. And what rains did develop this afternoon -- a result of our moist air and daytime heating -- die off into the evening. Look for fair skies by the evening with clouds and pockets of fog slowly returning after midnight. It should be a dry start for Friday’s morning drive and bus ride with temperatures in the upper 60°s.

It’s another warm and somewhat humid Friday afternoon on the way with highs in the mid to upper 80°s for the WAFB viewing area. Given the set-up, spotty-to-isolated showers can be expected for the afternoon but whatever does develop won’t last long -- let’s call it rain chances at 20% or less. All in all, looking good for Friday evening’s ‘Live After Five,’ LSU Baseball, or anything else around the area.

Saturday's forecast? Ditto on Friday: upper 60°s for sunrise with pockets of fog, afternoon highs in the mid to upper 80°s and rain chances at 20% or less.

What about Mother’s Day? If you’ve been following our forecasts this week, we’ve been generally going with a 30% chance of afternoon showers for Sunday. The news is a little better as of this afternoon: we’ll go with just a 20% chance of rain and a forecast for the day that is nearly a carbon-copy of Friday and Saturday.

After that very wet April, our recent run of mostly-dry days has been welcomed. But we don’t want to get too dry, and it looks like Mother Nature will accommodate. A storm system over the Central Plains this weekend will send a cold front our way for early next week. Plan for scattered rains on Monday with scattered-to-likely rains on Tuesday. The extended guidance is somewhat divided on what happens after that -- does the front sweep through far enough to deliver a noticeable cool-down and a return of dry days or does it linger in the region as a stalled front that keeps our weather unsettled? 

For now, we suspect only a limited drop in temperatures with this front and we are currently leaning to continued scattered rains for Wednesday and Thursday.

As for “Invest 90L” off the southeastern Atlantic Coast, the National Hurricane Center (NHC) has again increased the chances for tropical or sub-tropical development, now giving 90L an 80% chance of becoming Ana over the next two to 5 days (as of 12:45pm today). Based on the latest satellite presentations, it seems probable that the NHC will ‘upgrade’ 90L to Ana in the next two days and define it as a sub-tropical storm.

As a reminder, sub-tropical systems are hybrid systems caught midway between extra-tropical lows and fully tropical systems, showing some characteristics of both. While sub-tropical storms tend to be less energetic in terms of damage potential, they tend to be more expansive than tropical storms and hurricanes. Interests along the U.S. Eastern Seaboard -- especially the Carolinas -- need to pay close attention to this system, but it offers no threat to the Gulf. 

Wednesday, May 6, 2015

Slightly Better Rain Chances on Thursday

By Jay Grymes & Steve Caparotta

May 6th WAFB First Alert Quickcast:

- local weather status quo: isolated showers possible through Saturday
- “Invest 90L” no threat to the Gulf

Our recent set-up of mostly-dry days with isolated showers and highs in the 80°s continued today and is expected to hold through Saturday.

While the breezes may have done a number on your hair today, they are helping to make our warm and somewhat-humid afternoons reasonably comfortable.

We got a little cooler than expected this morning, with Metro Airport (BTR) dropping to a low of 61°, in part because we had less cloud-cover than expected.  For this afternoon, we picked up a couple of Doppler radar returns through the afternoon but it was very limited ... and anything that fell was generally on the light side with little if any thunder in our viewing area.

Our forecast for Thursday calls for a slightly higher chance for a backyard shower and we do expect both the morning lows and afternoon highs to be a smidge higher.  Let’s go with Red Stick area sun-up temperatures in the mid 60°s for Thursday morning and afternoon highs in the mid 80°s with a 20% to 30% chance of afternoon and early evening showers.

Friday and Saturday may be a slight bit warmer.  Plan for muggy mornings in the upper 60°s for both days, largely due to a slow-but-steady increase in dew point temperatures (a measure of low-level humidity).  Afternoons will be a little warmer and stickier too for most WAFB neighborhoods: we’ll go with mid to upper 80°s for both days.  As for rain chances?  20% or less for both afternoons.

For Sunday -- Mother’s Day -- we’ve been hovering in the 20% to 30% range for rain chances over the past several days and we’ll keep it there.  Plan for a muggier morning, with sunrise temperatures in the upper 60°s to near 70° for the Capital City and an afternoon high in the mid to upper 80°s.  What rain that does fall should be relatively short-lived, so stick with any outdoor plans that you have put together for Mom.

Headed into next week, we’re still anticipating a cold front to make its way into the lower Mississippi Valley, most likely arriving early Tuesday.  But the latest charts from the NWS Weather Prediction Center (WPC) suggest that the trailing end of that front may fizzle out before pushing through our viewing area.  We’ll go with scattered showers and t-storms for Monday and Tuesday for now, with the weather potentially remaining a little unsettled into Wednesday.  However, a fizzling front suggests no significant reduction in area temperatures, and maybe more importantly, no break from this week’s Gulf humidity.

As for the pre-season chatter about tropical development east of Florida?  Overnight the National Hurricane Center (NHC) labeled the area as “Invest 90L” (investigation area) and as of this morning the NHC significantly increased their forecasted development chances: 60% chance of development during the next two days and over the course of the next five days.  (The NHC’s 2:00pm update keeps those percentages at 60% for both the 2- and 5-day projections.)

As of this afternoon, there has been no confirmed center of closed circulation for 90L.  (As an aside, it is likely that when a surface low is confirmed it will be a non-tropical low.)  Until we have a closed low, forecasting the system’s track, intensity and even its potential evolution into a tropical structure is little more than educated guesswork based mainly on model projections.

In fact, the lack of a well-developed center is probably at least one reason why the NHC scrubbed the aircraft mission schedule for earlier today.  (Two flights are currently scheduled for Thursday with a third on the books for a pre-dawn mission Friday.)

Many, but certainly not all, computer models are ‘bullish’ on this system.  Residents along the Southeast U.S. coast- - from Georgia to the Carolinas - - should begin preparations for a potential landfall of either a sub-tropical or tropical storm by or even before the weekend.  If 90L does reach one of these stages, it would be named ‘Ana.’

Yes, it’s early but it’s not entirely rare for tropical storms to form before June 1st.  In fact, there have been pre-season storms (including hurricanes, tropical storms or sub-tropical storms) in 10 of the past 50 years, with two pre-season storms forming in 2012 (TS Alberto & TS Beryl).

Tuesday, May 5, 2015

No Major Changes Ahead...

By Jay Grymes & Steve Caparotta

May 5th First Alert Quickcast:

- isolated showers for Wednesday through Saturday
- an update on weather near Cuba and the Bahamas

Happy Cinco de Mayo!

As expected, it was a mainly-dry day today with just a few short-lived blips on our regional Doppler radar.  Highs climbed into the low to mid 80°s across the region for the afternoon. While dew points were in the low to mid 60°s, fairly persistent breezes through the afternoon kept the air reasonably comfortable, making for a nice May day.

Clouds will slowly increase late tonight and into Wednesday morning, with morning lows in the low to mid 60°s for most WAFB neighborhoods.

Wednesday will again be mostly dry across the area -- we’re going with a 20% chance of afternoon t-showers.  A modest mid-level “lid” on the atmosphere that inhibited showers today will weaken just a tad by Wednesday afternoon, allowing a few showers -- and even a pop or two of lightning -- to get going.  Like today, plan for highs in the low to mid 80°s for Wednesday afternoon around the region.  And like today, whatever showers do develop should be gone by sunset.

Our current forecast stays with spotty-to-isolated mainly afternoon showers for Thursday, Friday and Saturday -- rain chances at 20% or less each day.  However, a steady fetch off the Gulf will mean a slow increase in low-level humidity through the work week.  As the dew points rise, so will morning minimums.  In addition, the afternoons will get a tad warmer and more humid too. 

For Sunday, Mother’s Day, we think that the weather gets just a bit wetter: we’re posting a 30% rain chance for Mom’s afternoon.  Sunday won’t be a wash-out: more along the lines of a summer-type of day with hit-or-miss afternoon t-showers.  Stick with the BBQ plans.

The extended outlook into early next week features a cold front approaching from the northwest.  Yesterday’s guidance suggested a Monday arrival for the front.  However, today’s latest from the NWS Weather Prediction Center (WPC) delays the front until Tuesday.  The American GFS model is none-too-impressed by the front based on its latest rain projections, while the European ECMWF is a little more bullish with its rain forecast.  For the time being, let’s go with scattered rains for Monday and Tuesday.  We can fine-tune over the coming days.

So what about that broad area of messy weather extending from near Cuba to near the Bahamas?  Yesterday, the National Hurricane Center (NHC) gave the region a 30% (low) chance of development during the latter half of this week.  Today, the NHC ‘upped’ the 5-day chance of development to 40%, adding in a 20% chance for the next two days.

So what does all this mean?  Well, we could have a pre-season ‘Ana’ on the tropical board by the weekend.  Virtually all of the computer models are showing some type of low developing, although they differ in terms of intensity and location. 

Most importantly for our local interests: no matter what happens, this is not going to be a threat for us.

If you’ve been watching the satellite presentation over the past 24 hours or so, two things are apparent:  (1) while there are some guesses, there does not appear to be a clear-cut surface low anywhere in that mess and (2) there is a fair amount of SW-to-NE flow aloft.

Now, if this were a tropical system, those upper-level winds would be counter-productive.  But the consensus thinking is that any surface low that forms will be non-tropical, at least in the initial phase.  If that is the case, the upper-level winds might actually be beneficial by enhancing the vertical lift and deepening the low. 

The question then becomes, should a non-tropical low form, could it then start to morph into a sub-tropical (hybrid) system?

When we go back to the computer models, the answer appears to be leaning somewhere between possible to likely.  In other words, we’re still far from a sure thing here, but if the non-tropical low could form, drift north and then meander over the warm Gulf Stream waters, then we could have a set-up for a slow transition to something sub-tropical. 

The NHC still has an aircraft scheduled to visit the region tomorrow, although an official “invest” (area of investigation) has yet to be declared as of this writing.  Stay tuned!

Monday, May 4, 2015

Warm, Isolated Showers Through the Week

By Jay Grymes & Steve Caparotta

May 4th First Alert Quickcast:

- a mostly-dry forecast through the work week
- what’s up with the tropics?

We hope that you had at least a little time to enjoy the weekend weather -- a great way to start off the month of May.  And keep in mind, summer-like heat-and-humidity is just around the corner, so get outdoors while we can still enjoy these relatively comfortable afternoons.

Speaking of humidity, you may have noticed a slight uptick in that department through the day: not uncomfortable, but not “dry” either.  After opening May with Baton Rouge dew point temperatures in the low to mid 50°s, we were in the upper 50°s yesterday and those numbers have risen into the 60°s today.  That’s just about average for May in the Red Stick and still a far cry from the traditional summer dew points in the 70°s. 

So not summer-sticky just yet, but probably enough to get many of you to run the A/C to dry-out the air in your home.

An easterly wave (a surface trough of low pressure tracking from east-to-west) over the north-central Gulf provided sufficient lift today with our low-level Gulf moisture to generate a few showers and even flashes of lightning during the afternoon.  The wave will continue to the west through the evening, taking its influence on our local weather out of the picture.

After today, there are no major rain-making features that are expected to impact our local weather.  Surface high pressure will remain parked over the eastern U.S. into mid-week with the central Gulf Coast under a south-to-southeast low-level flow.  That means continued flux of Gulf moisture into our area.

Daytime highs for metro BR will hover around the mid 80°s for much of the week, possibly climbing into the upper 80°s for many WAFB neighborhoods by week’s end.  With the rising dew points thanks to southerly flow, morning lows will display a slow-but-steady rise through the 60°s.

We’re expecting a drier Tuesday compared to today, although a spotty shower or two can’t be ruled out.  Even without any significant weather features -- like surface fronts -- to provide lift for our muggy air mass, our daytime heating over the next several days should be enough to spawn a shower here and there each afternoon, especially closer to the coast.  Remember, warm-and-moist air is always ready to rise … and our daytime heating in the coming days should be enough to generate spotty to isolated pockets of brief rain each afternoon.

That means daily rain chances at 20% or less through the work week.  In fact, as of now, our next significant shot at area rains is not until Sunday.  

So ... about the tropical chatter you might have heard over the past few days.

Just about every major forecasting model is showing some sort of low-pressure area developing to the north of the Bahamas later this week.  An area of disturbed weather currently near Cuba is expected to track northeast and then turn north by mid-week.  There is a chance that this area could take-on tropical characteristics if it were to sit over the very warm Gulf Stream paralleling the U.S. Southeast Coast.

What kind of chance?  The National Hurricane Center (NHC) currently says a 30% chance over the next three to five days -- a low chance -- of becoming something tropical.  In fact, the NHC is suggesting that if it were to develop, it would probably be a sub-tropical storm. 

Sub-tropical storms are hybrid storms, caught somewhere between being non-tropical and fully-tropical systems.  Generally, sub-tropical storms tend to be less energetic than tropical storms, but tend extend over a larger area than their tropical cousins.  And just like tropical storms, they can produce strong winds, locally heavy rains and storm surge.

Interestingly, while the NHC is currently posting development potential at a low 30% later this week, they already have scheduled an aircraft reconnaissance for Wednesday on the presumption that something of interest will emerge north of the Bahamas by then. 

In the meantime, this is certainly not something for WAFB and other local interests to get concerned about.  Even if this system were to become a sub-tropical or tropical storm (it would be named ‘Ana’), it offers no threat to the Gulf.  Maybe more importantly for us, pre-season storms are not omens of an active season ahead.