El Niño developed back in March and continues to show signs of strengthening and is forecast to continue through the spring of 2016. This El Niño has the potential to become one of the three or four strongest events since, 1950, along with 1972-73, 1982-83 and 1997-98. Remember, the warming of the equatorial Pacific waters affects the location of the jet streams. During a normal winter, the jet stream comes ashore across the Pacific Northwest but during an El Niño winter, the southern jet stream hits California. In general, the effect of El Niño on California is increased rainfall with accompanying floods, landslides, and coastal erosion. The effects usually vary across the state and are more predictable in Southern California.
ALABAMA TYPICALLY SEES WETTER AND COOLER THAN NORMAL WEATHER!
Brad Rippey, USDA Meteorologist says there was a usually early onset of El Niño, as it began in the spring of 2015. Rippey says a more typical onset time is late summer or autumn, with peak intensity near the end of the calendar year. The 2015 El Niño arrived early enough to influence late-spring U.S. weather patterns, and almost certainly contributed to the heavy spring rain in Texas and elsewhere in the south-central U.S.
This El Niño event so far, has had a profound influences suppressing the Atlantic tropical season and enhancing the eastern and central Pacific tropical systems. This is typical during El Niño events. Rippey says, major U.S. weather effects should begin to appear in earnest during the autumn months, starting with increasing wetness in much of the southern U.S. and mild, dry weather in mainly northern areas, including portions of the Northwest and Midwest.
For California, statewide precipitation totals of at least 150 percent of normal would be needed between October 2015 and March of 2016 to put a significant dent in the four-year drought, says Rippey. More than 80 percent of California’s annual precipitation typically occurs during that six month period.
Only five times has California's statewide annual (July-June) precipitation totaled more than 150 percent of average:
1. 1982-83 40.11 inches 179% Super El Niño
2. 1997-98 38.10 inches 170% Super El Niño
3. 1994-95 36.33 inches 162% Nearly continuous El Niño, 1991 to 1995
4. 1940-41 34.69 inches 155% Nearly continuous El Niño, 1939 to 1942; ended Dust Bowl
5. 1977-78 33.81 inches 151% Weak El Niño, ended California's mid-1970s drought
45. 2009-10 23.59 inches 105% El Niño
It’s interesting to compare sea surface temperatures during the last few El Niño events to the current sea surface temperatures which are much warmer across the northeast Pacific Ocean. The warm equatorial Pacific water will continue to affect the upcoming weather patterns and with this abnormal warmth to the north of that zone, it could also affect the pattern.
9-14-2009 El Niño SST: Notice the cold (blue) SST in the Gulf of Alaska:
I asked Brad Rippey, USDA Meteorologist his thoughts regarding how warmer ocean temperatures combined with El Niño could impact the jet stream patterns: “This is purely speculative, as I am not a research scientist but more of an operational meteorologist. I feel that this El Niño is becoming so strong that the sub-tropical jet stream will deliver a potent moisture stream to at least southern California and possibly areas farther north, even if a ridge of high pressure persists over the northeastern Pacific Ocean. In other words, jet energy should undercut the ridge, keeping at least the southern U.S. very wet from roughly October-April, give or take a month on either end. Some of the northern areas, including western Canada and the northwestern U.S., may remain at risk of staying dry.”
Rippy says, “An alternative scenario is that the northeastern Pacific warmth could add energy to any storms that make it into that part of the basin. Obviously, a high-pressure block would preclude storms from reaching the northern coast of North American, as we’ve seen the past several years, but any breakdown of that ridge could lead to powerful, warm-water fueled storms breaking through.”
*New long-lead outlooks from NWS/CPC will be out on Thursday, September 17.*
*Rippey's thoughts jive with some of the data I have researched and I am still leaning towards a wetter than normal fall in Central Alabama, the severe weather threat increasing especially in November and temperatures going from fairly normal if not slightly above to slightly below normal.*
JILL'S FALL FORECAST:
-Wetter than normal
OCTOBER AVERAGE PRECIPITATION: 3.44"
NOVEMBER AVERAGE RAINFALL: 4.85"
-Severe weather threat increases (especially November)
-Temperatures initially close to normal or slightly above
-Slightly below normal late fall temperatures
Jill Gilardi WBRC First Alert Meteorologist
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