Weak El Nino Modoki & Thoughts On My Fall-Winter-Spring-Summer 2012-13 Forecast

November 11th, 2012 at 11:19 pm by under Chad's WLFI Weather Blog

Weak El Nino continues in the equatorial Pacific.  In the eastern part of the equatorial Pacific, the warming has actually reversed & now most of the warming is in the central Pacific.  So, we have seen this evolve form a standard weak El Nino to now a weak El Nino Modoki episode.  Modoki episodes have increased in recent years compared to previous decades.

So, this is the less common version of El Nino where the central Pacific warming tends to lessen the normal El Nino shear that tends to rip apart hurricanes.  This change towards an El Nino Modoki is most likely the reasoning behind still quite a bit of hurricane activity in the Atlantic despite at least a weak El Nino episode late this summer & fall.

El Nino Modoki episodes occurred in 2009 (’09 kind of a hybrid of both during the winter), 2002 & 2004, as well as 1994 & 1991.  Modoki means “similar, but different” in Japanese, referring to that fact that El Nino Modoki is like an El Nino, but the warming is just shifting towards the central Pacific.  Thinking we will not see a reversal towards a Nina or total neutral conditions in the Pacific, despite reversal in eastern equatorial Pacific recently.  Still thinking this very weak El Nino may strengthen, but it will strengthen in the central Pacific, not eastern to a continuation of El Nino Modoki.

I still like a cold, snowy Northeast U.S. with lots of Nor’Easters with that unusually warm water off the coast of New England with colder-than-normal water off coast of mid-Atlantic (some of that recently sue to upwelling from Sandy & recent Nor’Easter).

What does this mean for us?

I still like using 1934-35 as the foundation for the winter forecast.  This fall-spring featured a very weak El Nino.  It appears to most likely be a Modoki episode.  Soil moisture patterns in the U.S., winds of polar vortex & stratospheric ozone & sunspot numbers all look good with current forecast of bit above normal temperatures overall with normal snowfall around here.  Horrendous drought & extremely hot summer of 1934 ended in a cool, wet early fall.  Only deviation from this is that the cool & wet weather has continued pretty much through the entire fall, not just early fall here in 2012.  More sunspots & enhanced solar output will tend to force more neutral-positive NAO/AO than very negative this winter.  This still means a bit above normal temperatures, overall & lack of brutal winter, but still a more normal one.

Everything else looks good for on-going winter-spring-summer 2012-13 forecast.

NOTICE THE ORANGISH COLOR IN THE MIDDLE OF THE EQUATORIAL PACIFIC.  THAT IS A WARM ANOMALY ON THE SURFACE WATERS, BUT IS IS RATHER WEAK WARMING (0.5 TO 1.5 DEGREES CELSIUS).  NOTICE HOW INCREDIBLY ABOVE-NORMAL THE WATER IS OFF THE COAST OF NEW ENGLAND & COLDER WATER NEAR NEW JERSEY IN THIS MAP CENTERED AROUND THE START OF NOVEMBER.

FALL:  COOL, WET EARLY FALL, THEN DRIER & WARMER LATTER FALL………….

WINTER:  ABOVE-NORMAL TEMPERATURES & BELOW-NORMAL PRECIPITATION FOR THE WINTER WITH NORMAL SNOWFALL……

SPRING:  ABOVE-NORMAL TEMPERATURES & BELOW-NORMAL PRECIPITATION FOR SPRING…………BELOW-NORMAL SNOWFALL

SUMMER:  ABOVE-NORMAL TEMPERATURES WITH NORMAL RAINFALL NEXT SUMMER……………

FALL 2013:  WARM, DRY EARLY NEXT FALL (DROUGHT CONDITIONS POSSIBLE), THEN WET & COOL LATE FALL……….

EL NINO:  As of September 12, El Nino is weak in the Pacific with a 0.7 reading on a scale of 0 (neutral) to 3 (very strong El Nino)…………….(-3 would be very strong La Nina, -1.0 or 0.5 weak La Nina).

Forecast guidance suggests El Nino to increase in intensity to a weak event by December-January, then largely turn to neutral status by early next summer.  Wouldn’t be surprised if it gets a hair stronger, but not anticipating a big event.

Lack of Arctic ice due to warmth & strong winds of incredibly strong polar vortex & the strong polar vortex bottling some of the Arctic air up will make this winter nothing extremely warm, but not really cold either.  Snowfall will run normal, give strong subtropical jet interacting with some cold spells here.  One icing event is likely (mixed with snow & sleet in February), but it does not look major.

Volcanic aerosols are not above normal & given polar vortex personality last year & right now, thinking NAO/AO will spend a lot of time in the neutral to positive phase.

1934-35 was a strong match for the upcoming fall-winter-spring-summer in terms Northern Hemisphere pattern & U.S. soil moisture pattern.  1930, 1931, 1936, 1939, 1940 all had hot, dry summers with rainfall relief in early to mid-August, but only 1934 saw the heat wave migrate westward pretty much stay just west of us mid- to late-August through September, just like now.  Much higher soil moisture here developed by early September, while the Plains continued the same pattern as in summer (just like now).

1934-35 was not outstanding.  It had normal to above-normal snowfall & above normal temperatures & below-normal precipitation.

I think what will bring us normal snowfall is the strong, moisture-charged subtropical jet reacting with our seasonably cold air.  So, that is why I forecasted normal snowfall & two winter-storm watch/warning events.

Thinking the southwest U.S. mountains, southern Plains & mid-Atlantic & northeast U.S. could get pretty big snows.  There will be several big Nor’easters in the northeast with one significant ice storm in the Piedmont & coastal Plain of the Carolinas, into the Appalachians & as far north as Virginia.  It could be a really damaging ice storm.  Arctic airmass eastern Ohio to the Northeast will support very impressive lake effect (perhaps some record lake effect snows) around Cleveland, Buffalo & Jamestown.

I think unseasonable snows may occur at low elevations in the Desert Southwest with perhaps a record 4-6″ snow for Tucson, even Albuquerque may see a BIG snow event.  Flooding will be possible in southern California to Texas with snows in northern & central Texas to Oklahoma.  I think there may be one event where a cold upper low brings wet snow to Dallas, Austin with perhaps flakes to San Antonio & Little Rock.  The southern U.S. just looks wet with frequent rain & storms with a lot of chilly, gray days.  Strong subtropical jet will support a higher-than-normal potential of severe weather events in the South, specifically on the Gulf Coast & on the Florida peninsula.  Combine such moisture with cold air from all of the Northeast snow damming up in the Appalachians & you spell trouble for icing in the Appalachians, Piedmont & Coastal Plain (see above).

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