El Nino Weather Patterns - WAFB 9 News Baton Rouge, Louisiana News, Weather, Sports

El Nino Weather Patterns

Question:

This weather pattern is killing us, keeping the Gulf of Mexico churned up all through a very good Tuna fishing season.  What are the long range forecast saying? When can we expect this pattern to change back to a normal cold front every 4 or 5 days?


Answer:

You've probably been getting a bit fed-up with my near-daily "El Nino this ... "  and  "El Nino that ..."  comments in recent weeks, but I believe that El Nino is a major reason why the water's been stirred up so frequently.  Yep ... El Nino normally creates a "cool & wet" winter and spring across south Louisiana - just like we've suffered through the last several weeks.  The wet pattern is largely the result of the very active and persistent sub-tropical jet stream (some call it the "southern branch of the jet stream").

But for your interests, El Nino may be a double whammy!

Here's how I see it: when the southern branch of the jet stream is active and persistent during the winter and early spring - like it has been these past weeks - we tend to see a greater number of Gulf lows develop in the western Gulf, just off the Texas coast.  The fast-moving winds at higher altitudes actually help increase and strengthen the development of these NW Gulf lows.  In fact, during some past El Nino winter/springs, we've seen double or more the number of these winter Gulf storms.  And, as you well know, these lows then track east or east-NE, making the weather - and the sea-state -- over the central Gulf and the near-coastal waters even stormier than they would be simply as a result of the high-level winds.

Surface winds are further increased by the pressure pattern that often develops ... low pressure over the Gulf waters with high pressure over land creates a steep pressure gradient with steady - and often very gusty -- winds from the NW, N and NE.  Result:  Small Craft Advisories galore!

Bottom line - I do expect breaks in this overly persistent pattern, but chances are that these breaks may sometimes be rather short-lived and that the jet stream pattern and active storminess will return (frequently?) over the next 1 to 3 months.

So .. is there any good news? Well ... maybe. All that I mentioned above is based on a review of moderate to strong El Nino events in the past.  This current event is rated as a relatively weak El Nino (so far, at least).  That means that our confidence for continued wet weather (and frequent Gulf low development) is not as high as it might be if this were a "strong" El Nino.  In other words, we could see a relaxing of the recent jet stream pattern in the coming weeks.  Emphasis on the word "could" ... so, I would recommend that you consider prepping for more of the same, while hoping for better.

And as for a return a non-El Nino pattern of cold fronts every 4-6 days ... don't count on it.

Hope this helps!

Jay Grymes
Chief Meteorologist
WAFB Storm Team

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