KATC StormTeam 3 Weather BLOG

I’m not a big fan of saying whether it will be a “mild” or “cold” winter…we have had plenty of milder than normal winters in the past where temperatures have averaged well above normal but we have had one shot of 15 degree weather.  Most folks will remember that as a cold winter. 

Other previously mild winters we have seen accumulating snow…perception cold winter.   I can recall playing golf on a past Christmas Eve in shorts in a colder than normal winter…what did I remember from that winter…playing golf!  Far too many times as we say in the weather and TV business, “perception is reality”.

The bottom line is that each winter we have on average 20-30 days of 70 degree plus temperatures (December through February) and this year will be no different.  Some years we barely get below freezing but for a handful of days or less…other years we’ll see more than 5 or 6 mornings where we plunge into the mid-20s…like last year. 

Incidentally last December through February was a “colder” than normal winter with temperatures in Acadiana ranging more than 5 degrees below normal…and it started with the earliest snow on record on December 4th!  That winter was followed by the warmest summer on record in Acadiana!

Everybody is asking me this year is whether we will see snow?  If your forecast is based just on long-term trend forecasts many think the odds below or above normal can be determined…but as we all know, Mother Nature’s randomness decides whether we’ll see a snow or a hurricane for that matter. 

Long-term trend forecasts are not that good.  So I say with above normal forecast confidence, that anything can happen!  A ringing endorsement by the non-committal!

The Climate Prediction Center did forecast slightly cooler than normal and wetter than normal conditions last winter but they are going with the opposite for the balance of this winter through March. 

The predictions are calling for in general, above normal temperatures accompanied by below normal precipitation patterns.

This year the temperature forecast calls for a fairly good signal for above normal temperatures as the developing La Nina should induce more ridging across the south. 

The pattern of the last few weeks of November through the first two weeks of December may favor this pattern with regular cold fronts but with milder than normal return periods. 

Forecast confidence is below normal for the temperature pattern however, as just a slight shift of the mean winter longitudinal cold front axis could translate to much warmer or much colder than normal.  We’ll see.

Precipitation forecasts are calling for below normal rains which does not bode well for Acadiana and the state for that matter, as most of the region is in a moderate to severe drought with many spots across the west central and northern part of the state mired in an extreme drought.

Finishing off 2010, rainfall in Lafayette is more than 20 inches below normal.  If drier than normal conditions continue through the winter, they may likely perpetuate through the spring.  This could set the stage for a serious drought situation for much of the state until tropical season arrives.   It is never good when you are wishing for a tropical storm or hurricane to end a drought. 

Based on current trends, forecast “confidence” is above normal for the precipitation pattern.

Droughts have had a history of becoming multi-year events in Acadiana and this may be the start of one such period…again, we’ll see.

Drs. Klotzbach and Gray at Colorado State issued there 2011 Hurricane Season Forecast today indicating that the above normal Atlantic Basin hurricane activity will continue for 2011.  Their report cites that above normal Atlantic sea surface temperatures will likely continue on its multi-decadal high while the absence of El Nino will allow for better than average tropical numbers.

The forecast calls for 17 named tropical storms, 9 hurricanes and 5 major hurricanes…the average over the last 40 years is 11, 6 and 2 respectively.  These numbers are similar to the amount of activity in the Atlantic Basin for this past year where 19 storms, 12 hurricanes and 5 major storms formed. 

2010 was considered a very busy year, but the seasonal variations in weather patterns across the U.S. kept most storms either Atlantic systems or storms that were driven well to the south into Central America and Mexico.

The apparent wild-card going into next year is whether La Nina, that developed in 2010, will continue into 2011.  La Nina is cooler than normal waters that pool in the equatorial Pacific.  Typically during La Nina years there is less shear exhibited over the Caribbean and portions of the Atlantic that allows for more storms and more intense hurricanes.

The Colorado state team is not sure whether La Nina will continue into the hurricane season and their forecast is based on neutral La Nina conditions.  But if La Nina persists into the tropical season then their forecast numbers will likely increase.  On April 6 Drs. Kltozbach and Gray will update the 2011 season forecast based on the latest La Nina and other atmospheric trends.

As forecasted by Drs. Klotzbach & Gray and NOAA, the 2010 Hurricane Season was a very busy one with 19 named storms, 12 hurricanes including 5 major storms.  Fortunately for the U.S. most of the storm tracks were either Atlantic storms or systems that skirted well to the south of the Gulf Coast across the Caribbean and into Central America and Mexico.

While the amount of annual activity and hurricane potentials can be estimated quite well, forecasting where the storms are going to track remains as variable as our day to day weather patterns. 

This year was a very hot summer across much of the U.S. particularly over the nation’s mid-section and south.  In fact, June-August collectively were the hottest on record in Acadiana dating back through 1893.  This was due to a large high pressure pattern that led to a very hot and dry summer for Louisiana and Acadiana.  The strength of this ridge induced slight (or just enough) low pressure troughing along the East U.S. coast thereby steering most storms away from the U.S.  This semi-permanent ridge also shunted most activity away from the Gulf of Mexico keeping low latitude systems well to the south.

This past year had many similarities as compared to the very busy season of 1995 when none of the big storms struck the U.S.  In fact, no hurricanes made landfall along the entire U.S. coastline this year marking the first time in recorded history that as many as twelve hurricanes occurred in the Atlantic basin without a U.S. landfall.

Our luck has continued from 2009 with only three tropical storms making landfall in the U.S. over the last two years equalling the last “quiet” period during the 1990-1991 hurricane seasons.  It has been even better for the Florida Peninsula and East Coast as for the first time since reliable records have been kept dating back to 1878 that no hurricanes have made landfall in the last 5 years.

So while the forecasts were quite ominous for this past hurricane season, the amount of U.S. damage was minimal…this was due mostly to seasonal atmospheric variability outside of the tropics.  Unfortunately there will likely be more busy seasons ahead and our luck may run out and the statistics will “right” themselves…for now we can breathe easy until next year.

The preliminary blush on next year should be quite busy again with La Nina developing in the equatorial Pacific…this is usually a hurricane intensity and frequency enhancer in the Atlantic Basin.  Colorado State’s forecast for 2011 will be issued on December 8th…stay tuned.

Widespread rain and thunderstorms in the first couple of days in November brought impressive rain totals to Acadiana mainly across the I-10 Parishes southward.  Coastal parishes experienced the heaviest rains with totals generally in the 4-6 inch range. 

Hot spots in Vermilion Parish exceeded 8 inches across from Abbeville southwestward where flooding occured including water in some homes. 

Rain totals in Lafayette were in the 2.5-3.5 inch range while most areas north of I-10 indicated 1-2 inches of the wet stuff.

These rains have certainly eased the severity of the on-going drought, but the area will likely stay in “moderate to severe” drought status as many areas remain more than 10-15 inches below year to date normals.

In addition, due to the recent rains, the burn ban has been lifted.  Dry conditions will stay in Acadiana through the second week of November with the next significant chances of rain arriving about mid-month.

Our very dry weather pattern over the last several months has manifested into a severe to extreme drought for western portions of Acadiana and for much of the southwestern and western part of the state.  Fortunately rains earlier this week have eased the drought over portions of Acadia, Lafayette and St Martin Parishes.

Assuming Acadiana experiences normal precipitation patterns through the rest of the year, 2010 will likely fall within the top 10 driest years over a 117 year time span. 

Currently Lafayette has officially received 32.53″ of rain when normally we should be near 49.79″.  If Acadiana receives normal precipitation for the rest of the year (roughly 10″) then 2010 go into the record books in the top 10 driest years.

With La Nina developing the long term pattern this winter should bring continued below normal rains.  So it will be interesting to see how things play out for the balance of the year. 

Normally Acadiana receives approximately 60″ of rain per year with the driest being 35.80″ in 1924 and the most 98.72″ in 1940 (where a slow moving August hurricane produced more than 24″ in 48 hours in Lafayette).

Below are the top 10 driest years on record in Acadiana.

1.  1924-35.80″                             

2.  1902-37.25″

3.  1917-37.70″

4.  1936-41.15″

5.  1954-41.65″

6.  1962-42.33″

7.  1938-42.92″

8.  1960-42.98″

9.  2005-43.38″

10. 1999-44.86″

Hurricane Hunters investigating a disturbance in the Northwest Caribbean near Honduras this afternoon found robust tropical storm force winds and thus the National Hurricane Center upgraded this system to Tropical Storm Paula.  The 16th named storm of the 2010 season.

Paula was sporting 60mph sustained winds Monday afternoon as it raked the northern coast of Honduras.  Paula is forecast to become a hurricane Tuesday and will likely bring very heavy, flooding rains to Honduras, Belize and the Yucatan Peninsula this week as the system is expected to meander in the Northwestern Caribbean through the end of this week.

Ultimately this system will get caught up in the westerlies and move northeastward or eastward affecting Cuba this weekend.  Residents of South Florida may also have to keep an eye on this meandering system later this week.

Paula will not be a threat to Louisiana as strong upper level westerlies will keep the state and Acadaiana high and dry through the weekend.

Although the Caribbean may stay active over the next few weeks the current and future upper level pattern over the Gulf of Mexico and Southeast U.S. has essentially shut down the tropical season for 2010.  Upper level winds will stay hostile for any potential tropical activity while recent cool fronts are helping to cool some of the near shore Gulf waters.  Although there have been a few freak storms in the past during late October and November in the Gulf, the risk of any significant system in the Gulf of Mexico for the rest of the year will likely be less than 5%.  Unfortunately with a La Nina developing, an enhanced 2011 tropical season may be likely.

It has been a busy season with 15 named storms and 7 hurricanes with a couple more possibly to go, however the primary storms tracks have either stayed and re-curved well into the Atlantic or taken a more southern route toward Central America and Mexico, similar to the active 1995 hurricane season.

The 15th named storm of the season was upgraded to “Sub-Tropical Storm Otto”  Wednesday afternoon after Hurricane Hunters found strong tropical storm force winds force winds at flight level.  Otto made the transition to a full fledged tropical system Thursday as it heads northeastward into the open Atlantic.  Otto has some limited potential to become a hurricane over the next couple of days before running into cooler water and more hostile upper level conditions.

Otto was initially considered a sub-tropical storm as it’s energy was getting derived from a combination of warm surface water and the upper level dynamics of low pressure aloft.  Normally, purely tropical systems derive all there energy from warm surface water temperatures and the latent heat of evaporation that fuels convection (thunderstorms) in the storm system. 

Sub-tropical systems are fueled by the tropical process plus get energy and interact with low pressure and/or upper level jet dynamics.  Purely tropical systems are characterized by low pressure at the surface with high pressure aloft that allows for venting of tropical updrafts, which in turn keeps the tropical heat engine churning.

The Caribbean should stay active with couple of more storms possible over the next several weeks, into November, but fortunately for us Gulf dwellers, we have dodged the bullet again at least for this year.

Long range models continue to indicate that the tropics will stay active over the next few weeks with potentially two more systems (in addition to current TD16) to emanate from this area through mid-October.  Recent trends across the northern Gulf States will insure that any activity over the next 8-12 days will move north to northeastward out of the Caribbean toward Southern Florida and/or the Bahamas.  Portions of the U.S. East coast may also stay in the mix.   

Meanwhile the persistance of a nearly stationary monsoonal tropical trough over the Caribbean through mid-October will more than likely will translate to some serious flooding events from the Yucatan through Cuba, and Hispaniola…not particularly good news for the nearly one million people still living in tents in Haiti.

Locally, although we can’t definitively say the tropical season is done with for the northern Gulf of Mexico and Louisiana, it continues to look more and more promising.  Hopefully Acadiana will make it through this active season unscathed, but a late season storm is still possible, especially in active years; Hurricane Juan comes to mind in in 1985 which was a late October meandering storm.  Fingers staying crossed!

Tropical Storm Matthew is making landfall this afternoon along the Nicaragua/Honduras border and promises to produce torrential downpours and leaf-threatening flooding from Honduras, through Belize and portions of Mexico this weekend. 

This system will become nearly stationary and may become ill-defined or even dissipate this weekend, but computer models insist that broad low pressure will dominate across the Western Caribbean well into next week with potentially another surface circulation developing and then getting drawn northward toward Florida and possibly portions of the SE U.S. during the first few days of October.  The next named system will be “Nicole”.

A strong upper trough and surface ridge of high pressure will advance toward Louisiana this weekend into early next week insuring all tropical activity should  stay away from Acadiana for at least a week while we enjoy fall-like temperatures.

Long-range computer models do indicate additional tropical activity likely in the Caribbean Region well into the second week of October so the active hurricane season will likely continue for several more weeks. 

Most years the threat of major tropical activity that could threaten Acadiana ends after the first week of October, and it does look quite promising for us through the first week, but with the possibility of a very active Caribbean persisting for a while longer we may have to keep that window of opportunity open for another extra week or two…keep your fingers crossed!

A disturbance in the Eastern Caribbean continues to garner more attention from the National Hurricane Center as a weak area of low pressure has formed along a tropical wave that is traveling westward.  The disturbance has potential to become the next tropical storm and perhaps a hurricane.  The next named system will be “Mathew”.

Short range computer models and environmental conditions support tropical storm development by Thursday while longer range models remain rather murky on the details thereafter.  The system is expected to approach Central America by this weekend but the models have been insisting on a stalling system that may get induced northward toward the Gulf of Mexico with time. 

Stalling systems in the Western Caribbean could potentially produce life-threatening flooding and that may be a reality as the system possibly interacts with land areas this weekend into early next week.

Meanwhile, a series of cool fronts and stronger high pressure ridging over the central U.S. in the 1-2 week time-frame may contribute to a northward draw of this tropical system but could also force any northward moving system to the northeast, ultimately toward the Florida Peninsula in the first few days of October.  This would be potentially good news for us in Acadiana, but perhaps bad news for residents of South Florida.

Climatologically, northward Gulf-bound tropical tracks shift eastward toward Florida as the calender changes to October and this potential system may follow suit.  As always, forecasting large and small scale weather systems in the 1-2 week time-frame can change quite drastically so we’ll be watching closely how the pattern will evolve over the last days of this month into early October.