Wednesday, October 31, 2012

The Warm-Up Continues!

By Jay Grymes & Steve Caparotta

Wednesday was a mighty fine day across the WAFB ‘country,’ and the evening weather promises to be kind to the little Gremlins as they run through area neighborhoods. We’re calling for temps to slip from the mid 70°s around 6pm to the mid to upper 60°s at 8pm -- the hours for Trick-or-Treating in EBR Parish.

Skies will stay mainly clear overnight, with sunrise temps in the low 50°s for metro BR. Thursday will be another beauty, with mostly sunny skies and highs getting just a tad warmer, reaching the low 80°s. It will be warmer still for Friday.

An upper-level ridge currently located just to our west will steadily shift eastward over the next few days, becoming centered over the lower Mississippi Valley by Friday, then continuing east into the weekend.

We’ll continue to warm-up as the ridge approaches and sits overhead, but as it moves to the east, it will allow our next front to approach. For now, we’re still calling for a warm and mainly-dry afternoon for Saturday -- LSU Game Day as the Alabama Crimson Tide comes a’calling. A return of southerly flow ahead of the weekend front will mean spotty showers possible for Saturday afternoon and early evening, but not enough for concern for tailgaters or those lucky enough to have tickets to the game.

But the front is scheduled to arrive on Sunday, and we’re going with scattered rains -- currently setting rain chances at 40%. The front clears out by early Monday, delivering a cooler but not cold air mass and setting the region up for a good looking “Election Tuesday.”

Thankfully for the northeastern U.S., the “super storm” named Sandy has weakened considerably over the past 24 hours, and while ‘she’ is still readily evident on radar and satellite imagery, the system has lost much of its punch. No doubt, the recovery will be ongoing for weeks, even months. But much of the region has already made great strides in the long recovery, and much of New York City is back in operation. Still, when all the numbers are in, don’t be surprised if Sandy proves to be the most expensive natural disaster ever for the United States!

Tuesday, October 30, 2012

Looking Good for Halloween!

By Jay Grymes & Steve Caparotta

With the low dipping to 36° at Baton Rouge’s Metro Airport this morning, we awakened to the chilliest morning for the WAFB viewing area since February 12th. Now, if the mid 30°s and even some pockets of frost are a little too close to winter weather for your comfort, we’ve got some good news: the warm-up that began today will continue through the work week.

Overnight/early-morning lows for Wednesday will be considerably milder: we’re expecting mid 40°s for the metro area, with sunrise lows in the 50°s for the rest of the week. Highs today were in the upper 60°s to around 70° for most of us, and our forecast has highs back into the 80°s within the next couple of days for most WAFB communities. Mostly sunny skies -- like we enjoyed this afternoon -- will continue to be the rule through Friday.

There’s nothing but good news for the neighborhood Trick-or-Treaters for Wednesday evening: fair skies with temps starting out in the 70°s and only dipping into the mid to upper 60°s during the door-to-door haunts!

So a good looking work week, which then leads to the next big weather question: what’s the forecast for the monster LSU-Alabama clash in Tiger Stadium on Saturday night! While we’re putting a token “spotty showers” in the Saturday afternoon and early evening outlook, all-in-all the day looks like a good one for per-game tailgating and for watching what could be one the most pivotal game for LSU’s 2012 season!

Our forecast also includes a cool front over the weekend, likely arriving on Sunday afternoon and delivering a decent chance of rain as it slides by. Skies should be clearing by mid-day Monday, if not sooner, with “quiet” weather expected into the middle of next week.

As for Sandy ... she’s not “done” yet! Having fully transitioned into a huge “winter” cyclone, she continues to deliver winds, rain and snow to portions of the northeastern quarter of the nation. Storm impacts along the Atlantic Coast have been reported from South Carolina to Maine and as far inland as the Midwest and over the Great Lakes!

A very preliminary summary of the major impacts from Sandy include:
- upwards of nearly 8 million experiencing power outages
- rains of up to 8” to 12” over portions of eastern Virginia, eastern Maryland, Delaware and New Jersey
- snows of 2 feet or more over portions of West Virginia, Virginia, and western Maryland
- record storm surge and unprecedented flooding around New York City
- possibly the worst storm ever for coastal New Jersey
- cancelation of more than 16,000 airline flights

Although “hard numbers” are likely to be months away, very preliminary estimates suggest that losses from Sandy could top $20 Billion, possibly approaching $25 Billion, putting Sandy on a par with 1992’s Hurricane Andrew.

Peak wind gusts associated with Sandy.

Friday, October 26, 2012

Cool Weekend Ahead!

By Jay Grymes & Steve Caparotta

You have probably noticed the clouds increasing throughout the day. A cold front will slide through south Louisiana later tonight. If you have looked at radar you have probably seen the showers and the isolated t-storms moving through west Louisiana along and ahead of the front.

A few of you may get a little rain as the front passes by and folks north of Baton Rouge may even hear a rumble or two of thunder. But even those that do get rain won’t get much and the way it looks right now most of us will stay dry as the front goes by.

The big story with this front will be the drop in temperatures. Overnight clouds will give way to clearing skies by Saturday morning, and metro area neighborhoods will see sunrise temperatures in the 40°s. Saturday will be sunny, breezy and considerably cooler with highs for Baton Rouge topping out in the upper 60°s. It will be even chillier for Sunday morning with WAFB communities along and north of the I-10/12 corridor likely dipping into the 30°s for their morning starts. Sunday again will be breezy and cool with afternoon highs in the mid to upper 60°s. 

We’ll stay cool and dry for Monday and Tuesday with a modest warm up starting at mid week. The Halloween forecast looks good for the door-to-door Trick-or-Treaters. For the time being our outlook remains “mainly dry” right through next week.

Hurricane Sandy continues to be the BIG weather story for the U.S., with the latest model runs still turning Sandy back to the NW and landfalling along the Atlantic Seaboard. Sandy has weakened slightly today, but ‘she’ remains a very large system, with tropical-storm force winds extending as much as 200 miles out from the center!

The latest National Hurricane Center (NHC) forecast now maintains Sandy as a Category 1 hurricane right up until landfall, with the “forecast cone” at landfall currently extending from near the NC/VA state line to Long Island, NY sometime early on Tuesday. Admittedly, there is still a fair amount of uncertainty about what Sandy will ultimately do, but most of the computer models continue to advertise this somewhat unusual turn back towards the U.S. East Coast early next week.

Why unusual? One would expect that a tropical system that tracks so far to the north (as is forecasted for Sandy), especially for this time of year, would begin moving to the NE. In other words, a turn away from the U.S. at that latitude would be more along the lines of “climatology” (historical tendencies). But the deep trough that will deliver our chilliest mornings of the season this weekend is also expected to set-up a mid- to upper-level steering pattern that will cause Sandy to go against the “norm” and head back towards the mid-Atlantic or southern New England states.

If Sandy does head back and make landfall along the heavily populated U.S. Atlantic Coast as currently projected, the impacts of the storm’s winds, surge and anticipated flooding rains could lead to a storm for the record books!

Thursday, October 25, 2012

Big Changes This Weekend!

By Jay Grymes & Steve Caparotta

Thursday was another in a strong of warm and mostly sunny days, but BIG changes are just around the calendar corner. 
We’ll start Friday with another round of fog for the morning drive - - we could see a Dense Fog Advisory posted for some WAFB communities.  Morning temps will start in the low 60°s for metro Baton Rouge under otherwise partly cloudy skies.
The clouds will continue to build through the day on Friday as our next cold front slides southward through the Bayou State.  We’ve been talking about this all week:  this will be a “mainly dry” frontal passage.  We are currently posting only a 30% chance of rain for your backyard, and even if it does rain at your home or office, most of you will see less than one-tenth of an inch of rain with the frontal passage.

Yet the NWS is labeling this as a “strong” cold front.  Why?  Although we don’t anticipate much rain and no active or severe weather, the front will be delivering a much colder air mass in its wake.  In fact, it currently looks like Sunday and Monday mornings will be the chilliest mornings of the season thus far, with many WAFB communities along and north of the I-10/12 corridor dipping into the 30°s!
Our extended forecast stays dry through at least mid-week, so the forecast for Halloween Ghosts and Goblins should be fine.
However, for those looking for a little rain for the fall gardens: you might want to pull out the hose!
In the tropics, Tony has been downgraded to a “post-tropical” system as he races off to the ENE.  But the big tropical story deals with Category 2 Sandy.  Sandy picked up ‘her’ forward speed today after exiting eastern Cuba early this morning.  Sandy is moving through the Bahamas this afternoon and evening and will continue on a north to NNW track through the night and Friday.  After that, Sandy -- still with hurricane intensity and likely growing in terms of its overall wind field -- is expected to turn to the NNE or NE on Saturday. 
Normally, we would expect that turn to mark the end of any Atlantic Coast threat, but the extended forecast calls for Sandy to swing back to a north and then to the NW from Sunday through Tuesday. 
The latest official National Hurricane Center forecast has a Category 1 Sandy located to the east of the Delmarva Peninsula by Monday afternoon, but taking the storm into either the mid-Atlantic states or southern New England on Tuesday.  The status of Sandy at landfall is still a bit unclear: ‘she’ could still be a hurricane or may have transitioned to something “post-tropical” by landfall.  But given her expected strength and size for this East Coast landfall scenario, everything points to the potential for a devastating ‘hit’ for sections of the densely populated coastal corridor.

Wednesday, October 24, 2012

Another Round of Morning Fog...

By Steve Caparotta & Jay Grymes

Dense morning fog was the big weather story of the day for parts of south Louisiana. In fact, our visibility dropped to a half-mile by 2 a.m. at Baton Rouge Metro and didn’t climb back above a half-mile until after 8 this morning! Fog will continue to be a concern over the next couple of mornings, so remember to use low-beam headlights when driving.

After the fog burns off by mid-morning on Thursday, we expect a day much like today – partly cloudy skies and warm by the afternoon, with highs in the mid 80°s. A stray sprinkle isn’t out of the question, but the vast majority of us should stay dry.

It looks like we’ll have the potential for one more foggy start on Friday before we begin to see some changes in our weather. An approaching cool front will deliver a slight chance of showers or a t-storm by the afternoon and evening. We’re only posting rain chances around 20% from Friday afternoon until the front moves through early on Saturday.

In the wake of the front, big changes arrive in our weather over the weekend! Skies should begin to clear Saturday afternoon, with brisk northerly winds kicking in behind the front. Those northerly winds will usher in much cooler air, with Saturday’s highs only expected to reach the upper 60°s!

We expect to see a prolonged run of relatively cool weather beginning Saturday and continuing through much of next week. Morning temps will reach the low to mid 40°s by Sunday and continue into at least Halloween, while afternoon highs will range from the upper 60°s to lower 70°s.

In the tropics, Sandy was upgraded to 'Category 1' status at 10AM, making 'her' the 10th hurricane of the 2012 season. Sandy has been pounding Jamaica for much of the day, making landfall over the island-nation this afternoon. Sandy will strike eastern Cuba as a hurricane tonight, then track northward towards the Bahamas tomorrow. Hurricane warnings are now posted for the central and NW Bahamas, while Tropical Storm watches and warnings extend from the Florida Keys up much of the Sunshine State’s east coast.

The extended guidance is beginning to come in more agreement about potentially significant impacts from Sandy in some portion of the Northeast U.S. However, those potential impacts are still nearly a week away and considerable uncertainty remains.

Out in the central Atlantic, T.S. Tony -- the season's 19th 'named' storm -- continues tracking to the ENE and will do so for the next few days. The forecast for Tony includes a relatively short tropical "life," with increasing shear and cooler waters likely to accelerate Tony's transition to a "post-tropical" system within the next day or so.

19 'named' storms in a season ties four other years -- 1887, 1995, 2010 & 2011 -- as the third "busiest" season for the Atlantic Basin. The only two "busier" seasons were 2005 (the monster year with 28 'named' storms) and the recently-edited storm count for 1933 (now set at 20 storms). With five weeks to go, it is certainly possible that 2012 could reach that 20-storm mark, and 21 storms for the season is not entirely out of the question!

Tuesday, October 23, 2012

Was the 2012 Pre-Season Hurricane Forecast a Bust?

Jay Grymes
October 23, 2012

The 2012 Hurricane Season count has now climbed to 18 ‘named’ storms, with T.D. #19 expected to be upgraded to “T.S. Tony” -- the season’s 19th named storm -- later tonight or tomorrow.

19 ‘named’ storms would tie the number of storms for 1995, 2010, 2011 and way back in 1887.  And 19 ranks as the third most active season on the record books for the Atlantic Basin, topped only by the 20 (‘nameable’) storms of 1933 and the mega-active 2005 season (28 ‘named’ storms) when we ran through the alphabet and had to turn to Greek letters for names.

(In case you are wondering, with 38 days to go and with a storm being ‘named’ after November 1st during four of the past five seasons, it is very possible that we could see yet another tropical cyclone even after T.D. #19's upgrade to ‘Tony’ before season’s end.)

A look back at the season predictions from several renowned forecasting teams suggests that all of the hurricane prognosticators have been caught off-guard, again. A collective average of the 2012 predictions from these forecast teams as of the first week of June yields something on the order of 12-13 ‘named’ storms, with 6-7 becoming hurricanes, and 2 of those hurricanes reaching ‘major’ intensity (Category 3 or higher).

While there has only been one ‘major’ Atlantic hurricane thus far in 2012, the forecasts for storm numbers clearly fell short. And to be honest, this is at least the third consecutive season where the predictions under-estimated the number of storms to earn a ‘name.’ Yes, the science has a long, long way to go. But the science continues to improve and some aspects of the forecasts for 2012 weren’t completely amiss. Storm numbers are one thing, but there are other ways to measure activity in a hurricane season.

Some tropical experts prefer to focus on the collective storm energy produced during a storm season. One measure of this storm-season energy is defined by the ACE -- the Accumulated Cyclone Energy index. The ACE is a cumulative energy approximation, combining a measure of the peak sustained wind speeds of individual storms with their durations as tropical storms or hurricanes. An advantage of the ACE in terms of a season’s collective energy is that the ACE accounts for powerful and/or long-lived storms which can generate far greater energy than two, or even three, weaker systems.

In general terms, seasons with ACEs greater than about 110 are deemed as demonstrating “above normal” activity, while ACEs below 65 are “below normal.”

The table provides a summary of the eight “busiest” hurricane seasons based on storm counts. (Since ACEs have only been calculated back to 1950, we have no estimates for the 1933 or 1887 seasons.)

Not surprisingly, the mega-season of 2005 also shows the greatest ACE. But on comparing 2012 with other ’19-named’seasons, the collective storm energy of 2012 is lower, although 2012 might surpass 2011 before the season ends.  And note how much lower 2012 is compared to 1969 (Remember, 1969 had 12 hurricanes, 5 as 'majors,' including one named Camille!).

When we look at teh details of 2012, we find that nearly one-quarter of the season’s total ACE is attributed to a single storm -- the long-lived Nadine, a storm that is tied for second in terms of the total number of days in the Atlantic Basin at tropical-storm strength or greater.

So, while the storm-count projections fell short, the 2012 season is not that far “above normal” in terms of the ACE.

In the final analysis, however, some might argue -- and with good reason -- that the best measure for tropical activity deals with impacts and landfalls. If that’s your way of thinking, then Isaac makes the 2012 season a real monster for far too many WAFB communities!

Tuesday, October 16, 2012

Are We "Done" with the Tropics?

-- Jay Grymes & Steve Caparotta

Some of our tropical trivia buffs may be wondering, “What are the chances for more ‘named’ storms between mid-October and the close of the 2012 season?” Well, we did a little digging and here’s what we found:

First off, it’s important to remember that storm counts per year continue to run high compared to long-term averages. Some experts use long-term storm count averages based on seasons dating back to the early 1980s if no earlier, which includes a run of seasons with annual storm counts in the single digits. By contrast, there has been an average of 15 ‘named’ storms per season since 1995, generally considered the start of the current “active phase” of tropical cyclone development for the Atlantic Basin.

2012 is already well ahead of that average with 17 ‘named’ storms, thanks to Patty and Rafael. In fact, with more than six weeks left in the “official” season, 2012 already ranks among the top eight “busiest” seasons on record for the Atlantic! (Yep, so much for last may's pre-season expert forecasts!)

So, back to the original question: since the 1995 season (1995-2011, 17 seasons), we count 35 storms having been ‘named’ on or after October 16th. But admittedly, that includes 8 ‘late season’ (after Oct 15th) storms during the hyper-active 2005 season, when we had to dip into the Greek alphabet for names. 
Even if we remove the 2005 season from our simple analysis, we end up with 27 storms being ‘named’ after October 15th over 16 seasons (1995-2004, 2006-2011). That works out to roughly 1.7 storms per year, on average. And over all of the past 17 hurricane seasons, there have only been two seasons -- 2002 and 2006 -- with no storms ‘named’ after October 15th.


So, odds are, we could see one more, possibly even two more ‘named’ storms in the basin before we close the tropical books on 2012.

So then you might ask, “What are the chances for another ‘hit’ this season for the Bayou State?”

We can’t entirely rule out another landfall this season, but chances appear to be extremely low at this stage. Although Louisiana had ‘her’ one-and-only November ‘hit’ (more like a sideswipe) just a few years back with 2009’s Ida, history suggests that the western half of the Gulf of Mexico tends to become very inhospitable for tropical development around the start of November. Prior to Ida, 1985’s Juan is Louisiana’s only other recent “late season” landfall, pulling ‘his’ infamous pretzel-like loop-de-loop along the LA coast during the last week in October of that year.

In addition, while circumstances could change, upper-level winds over and near the Gulf have been somewhat active over the past few weeks. This may be a signal that the Gulf is “closed for business” for the remainder of the tropical season.

Or, at least, let’s hope so!

Paging and Bottom Toolbar

Friday, October 5, 2012

Big Changes over the Weekend!

Our latest guidance has the weekend cold front moving through just a little bit faster than we thought yesterday. As it looks now, the front moves through metro Baton Rouge Saturday evening rather than Saturday night or early Sunday morning.

This is an impressive system, delivering the first real taste of serious winter-like weather to portions of the central and northern U.S. Winter weather advisories are in effect for several states, and the NWS is forecasting for as much as 6” of snow over sections of the High Plains.

No, we won’t get a taste of winter this far south, but you will note a big chance between Saturday and Sunday! While we’ve tweaked the timing of the front’s arrival forward by several hours, that won’t mean any real change in our forecast for the weekend. Highs are still expected to climb into the upper 80°s for most of us on Saturday, with the big cool-down arriving Sunday morning.

The front still looks to be “mainly dry” -- we’ll add a token 10% rain chance to the forecast for early Sunday, but that is little more than forecast statistics to account for the unlikely chance of a sprinkle or two that might develop along and just behind the front as it passes by. By Sunday afternoon, we’ll enjoy a sun/cloud mix with highs in the 70°s -- a real return of autumn weather.

The cool air hangs around for another day -- Monday, Columbus Day -- but temps will quickly moderate after that, with mid to upper 80°s returning for Tuesday, Wednesday and Thursday. We’re also keeping a slight chance of rain in the forecast for the middle of next week.

In the tropics, Oscar succumbed to the shearing winds we noted on Thursday and satellite evidence suggests that ‘he’ lost his tropical characteristics this morning. Elsewhere, there has been a flare-up in the Bay of Campeche (SW Gulf) along the trailing end of an old frontal boundary interacting with a weak tropical wave. The action is being enhanced by upper-level winds, but any tropical formation appears highly unlikely given the fast-paced upper-level winds.

Thursday, October 4, 2012

Weekend "Cool down" Still on Schedule!

Thursday’s weather was great … and we didn’t have the concerns regarding Air Quality that had been forecasted for the day!

Our good looking Thursday will be followed up with a pair of warmer days for Friday and Saturday. Morning starts for both days will be in the low 60°s with afternoon highs in the upper 80°s. Plan on plenty of sunshine on Friday -- comfortably warm for ‘Live After Five’ -- and partly cloudy skies for Saturday.

Here is Friday's Pinpoint Forecast:

Yes, our expected weekend cool front is still on schedule for late Saturday, with the payoff coming in the form of mid 70°s for highs on Sunday and Monday! And we’ve taken just about any mention of meaningful rain out of the weekend forecast as well.

The cool down doesn’t last long however, with highs rebounding into the 80°s by mid-week.

Weekend travelers to Lorman, MS (Southern's Jaguar Nation) or to Gainesville (LSU) better take the poncho along, just in case. Neither game will be a "wash out," but both venues have a slight shance of rain (20% - 30%) during their respective game times.

We said “goodbye” to Nadine today, but not before ‘she’ became one of the three-longest-lasting storms at tropical storm/hurricane strength in the Atlantic Basin record books. And while we now have Oscar, the forecast calls for that storm to be gone in a day or so.

So ... are we done with ‘named’ storms for the 2012 season? With more than eight weeks remaining in the “official” season, we certainly can’t rule out another tropical wave reaching depression or tropical-storm intensity. But it is looking more and more likely that the Gulf of Mexico may be just about closed for (tropical) business for the remainder of the season!