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Pattern ENSO Updates

Discussion in 'General Weather' started by Snowfan, Mar 13, 2017.

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  1. NCSNOW

    NCSNOW Member

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    I'll take neutral heading into fall/ winter. 1st choice is weak el Nino. And I mean weak, hair above neutral.
     
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  2. cd2play

    cd2play Member

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    Wasn't 2009-10 a moderate El Nino? I was thinking it was on the border line between weak and moderate. I just hope we don't have another La Nina or even cool neutral.
     
  3. GaWx

    GaWx Supporter Member

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    It peaked at low end strong.
     
  4. Snowfan

    Snowfan Member

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    Latest ENSO discussion says no El Niño Advisory but nearly 50% chance of a El Niño by DJF.
     
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  5. accu35

    accu35 Member

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    Perfect timing
     
  6. ForsythSnow

    ForsythSnow Moderator

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    Not for my area it isn't. Every El- Nino for winter time always goes wrong and gives little to no snow. Get it out of here and into March!
     
  7. Snowfan

    Snowfan Member

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    Latest Nino 3.4 update has it warming to -0.1 C.
     
  8. Snowfan

    Snowfan Member

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    Latest Nino 3.4 update is the same from last update.
     
  9. GaWx

    GaWx Supporter Member

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    Indeed, Niño 3.4 stays at -0.1C:

    http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

    Note in this update that the upper equatorial Pacific OHC is not only holding up but it is starting to slowly rise again and is back above +0.80. If this persists into June, the chance at a weak to possibly moderate El Niño peak in late fall or winter would increase.

    At the same time, I have just learned about a 0.5 C warm bias in the May Eurosip ASO Niño 3.4 forecast based on 13 years of data. Therefore, I eagerly await the release of the May 2018 Eurosip ASO Niño 3.4 forecast. If it were to come in at only warm neutral, I'd have to favor no warmer than warm neutral for at least ASO even though it could subsequently reach weak El Niño later in the year. Even if it were to come in at weak El Niño in ASO, I'd have to remain wary about it happening as early as ASO due to this 0.5 C warm bias. Sometimes Eurosip has gotten this right but more often it has missed to the warm side. Then again, a persistently warm upper OHC may mean this would be one of the times Eurosip gets it right.
     
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  10. GaWx

    GaWx Supporter Member

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    The May, 2018, Eurosip ENSO 3.4 SST anomaly forecast through October was released today:

    https://stream.ecmwf.int/data/gorax...7-6fe5cac1a363ec1525f54343b6cc9fd8-2H4fDD.png

    I have it near +0.35 or warm neutral rather than weak El Nino for ASO averaged out. Based on what I've found to be a significant warm bias in the Eurosip, I'm now expecting no warmer than warm neutral for ASO despite a solidly warm subsurface that is now starting to rewarm slowly. Because of this warm bias and because we're still cold neutral, I can't yet count out cold neutral for ASO though I'm thinking warm neutral has the best chance right now due to the warm subsurface and since 5 of the 13 Eurosip forecasts turned out accurate. I still think it MAY get to weak to possibly low end moderate El Nino status by late fall or early winter, especially if the warm subsurface holds or warms.

    I found this warm bias by looking at how the ASO 3.4 SST anomaly forecasts made in the preceding May by Eurosip verified:

    Year: Eurosip's May fcast verification for ASO 3.4
    2017: 1.1 cooler (cold neutral occurred vs weak El Niño prediction)
    2016: 0.1 warmer (weak La Niña correctly predicted)
    2015: 0.1 warmer (strong El Niño correctly predicted)
    2014: 0.5 cooler (warm neutral occurred vs weak El Niño prediction)
    2013: 0.5 cooler (cold neutral occurred vs warm neutral prediction)
    2012: 0.9 cooler (warm neutral occurred vs moderate El Niño prediction)
    2011: 1.1 cooler (moderate La Niña occurred vs warm neutral prediction)
    2010: 0.9 cooler (strong La Niña occurred vs weak La Niña prediction)
    2009: 0.2 cooler (weak El Niño correctly predicted)
    2008: 0.8 cooler (cold neutral occurred vs weak El Niño prediction)
    2007: 0.2 cooler (moderate La Niña correctly predicted)
    2006: 0.2 cooler (weak El Niño correctly predicted)
    2005: 0.4 cooler (cold neutral occurred vs warm neutral prediction)

    So, of the 13 May forecasts for ASO, 5 were correctly predicted while 3 were one category too warm, 4 were two categories too warm, and 1 was three categories too warm. None were any categories too cold! The average was 0.5 too warm or one category too warm.

    Out of the 7 Eurosip El Niño predictions for ASO in the preceding May, only 3 verified. In contrast, Eurosip predicted only 3 La Niñas in ASO but 4 occurred.

    Of the 3 warm neutral predictions, 2 ended up one category too warm while 1 ended up three categories too warm. Of the 5 weak El Niño predictions, 2 ended up verifying correctly while 1 was one category too warm and 2 were two categories too warm.

    Out of the 13 predictions, weak El Niño was clearly the most common prediction (5) while warm neutral was 2nd most common (3). Next was weak La Niña (2). The remainder were each predicted once: strong El Niño, moderate El Niño, and moderate La Niña. There were no cold neutral or strong La Niña predictions though 4 cold neutral occurred (the most of any category) and one strong La Niña occurred.

    So, of the 13 May predictions for ASO, a whopping 10 were warmer than 0.0 while only 3 were colder. It turned out that only 5 were warmer than 0.0 while 8 were colder.

    The average May Eurosip ASO 3.4 prog during 2005-17 was for +0.4 vs the -0.1 actual.
     
    Last edited: May 22, 2018
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  11. Webberweather53

    Webberweather53 Meteorologist

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    Even after several weeks of strong trades east of the dateline, all it took was a momentary lapse over the past week and change, and now the downwelling kelvin wave over the CP is having little trouble infiltrating into the eastern boundary region, expect the NINO 1-2 & NINO 3 regions to warm quite a bit in early June. When your base state is characterized by strong-very strong easterly trade winds and you even a have a momentary hiccup to upset the wind-gravity balance, that could be enough to flip the ENSO state especially if there's already some pre-existing momentum in place like there was here. I still like the chances of a weak-moderate El Nino developing for this upcoming winter, the odds are probably at least double climatology (> 60-65%)

    wkxzteq_anm.gif
     
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  12. GaWx

    GaWx Supporter Member

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    The subsurface seems to be slowly rewarming. If this continues for a few more weeks, it is liable to exceed +1.0 C by mid summer. This would be a strong indicator that a weak to moderate El Niño peak in late fall or winter has a good chance. Otoh, that May Eurosip map suggests to me that the ONI (trimonthly) would very likely not reach +0.5 until after ASO.
     
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  13. GaWx

    GaWx Supporter Member

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    Indeed, this morning's weekly update has the OHC now up to a new high for this season of +0.94. That in itself tells me the odds are increasing for a weak to moderate Modoki El Niño peak late fall or more likely winter. However, the May Eurosip ASO forecast of only warm neutral tells me to expect any El Niño, should it occur, to be late in starting based on ONI since the May Eurosip has had a history of a warm bias. This is going to be interesting to follow.

    The weekly 3.4 update had no change and is still at -0.1.
     
    Last edited: May 29, 2018
  14. GaWx

    GaWx Supporter Member

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    The weekly update for 3.4 has it slightly warmer at 0.0. The OHC rose from +0.94 to +1.01, a pretty notable rise considering these already solidly warm levels.
    The MAM ONI came in at -0.4.
     
  15. GaWx

    GaWx Supporter Member

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    Warmest May OHC anomaly back to 1979/Later ENSO peak/May SOI

    +2.01 1997/ lead to strong El Nino/ May SOI: -19.0
    +1.53 2015/ lead to strong El Nino/ May SOI: -13.1
    +1.14 1980/ El Nino fail/neutral/ May SOI: -2.6
    +0.96 1982/ lead to strong El Nino/ May SOI: -7.1
    +0.95 2014/ lead to weak El Nino/ May SOI: +4.3
    +0.89 2018/ ???????????????/ May SOI: +2.7
    +0.87 2009/ lead to strong El Nino/ May SOI: -5.0
    +0.76 1991/ lead to strong El Nino/ May SOI: -17.9
    +0.61 1989/ warmed only to neutral/ May SOI: +15.1
    +0.58 1987/ lead to strong El Nino/ May SOI: -19.6
    +0.54 2006/ lead to weak El Nino/ May SOI: -7.7

    So, 8 of the 10 (80%) of the surrounding years were El Nino by late in the year. The two that failed had a May SOI of -2.6 (1980) and +15.1 (1989). Of the 7 that had a May SOI -5.0 or lower, 6 went onto a strong Nino peak and one went only to a weak El Nino peak. None of the 3 that were higher than -5.0 went to a moderate or stronger El Nino. This all tells me that the chance for strong El Nino by winter remains low, but the chance for weak (to perhaps moderate) El Nino is increasing. However, I still think ASO will only be warm neutral based on the warm biased Eurosip, which in May forecasted warm neutral for ASO.
     
  16. GaWx

    GaWx Supporter Member

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    I just noticed something quite interesting about the May, 2018, pressures at Tahiti and Darwin:

    Darwin monthly SLP: http://www.cpc.ncep.noaa.gov/data/indices/darwin

    Tahiti monthly SLP: http://www.cpc.ncep.noaa.gov/data/indices/tahiti

    - Tahiti's May, 2018, SLP, which was 1014.1, was the highest on record back to 1951! The normal is only 1012.7. The four highest on record preceding El Nino were 1013.9 (2014 and 1976) followed by 13.7 (2004) and 13.3 (1979), all 4 weak Ninos.
    - However, Darwin's was also above normal with its 1012.2. Only 9 of the prior 67 years had higher and 3 were the same. The four cited weak Nino years all had lower Darwin pressures ranging from 10.6 to 12.0. That's why all 4 of those years had a +SOI in May.
    - All of the above along with the latest Eurosip for ASO being only warm neutral tells me that any 2018-9 El Nino, which is strongly hinted at by the current +1.01 OHC, would likely be weak to low end moderate.
     
  17. Webberweather53

    Webberweather53 Meteorologist

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    I wouldn't get too caught up over the Eurosip forecast NINO bias, but it's better to look at the large-scale conditions rather than focus on the bias of the model forecasting those conditions because the latter is ridden w/ far more uncertainty and unknowns.
    In other news, this guy is a prime example of why you don't want to get caught in windshield wiper mode during every sub seasonal forcing change in the Eq Pacific. The integrated effect of several MJO events over a period of several months is what really matters and this favors weak El Nino regardless of whether we somehow get a few weeks of stronger than normal trades (which is normal btw), or the noisy southern oscillation index for a particular month or two is of "x" value.

    Screen Shot 2018-06-04 at 7.22.06 PM.png
    Screen Shot 2018-06-04 at 7.17.22 PM.png
     
  18. Webberweather53

    Webberweather53 Meteorologist

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  19. accu35

    accu35 Member

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    So all this means possible Weak/Mod Nino?
     
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  20. Webberweather53

    Webberweather53 Meteorologist

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    Yep, pretty much the same tune I've been singing for several months now
     
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  21. Webberweather53

    Webberweather53 Meteorologist

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    Some wonder why I've been so gung-ho on an oncoming El Nino this upcoming fall/winter for the last several months, this is why.
     
  22. GaWx

    GaWx Supporter Member

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    Nino 3.4 held at 0.0.

    Per yesterday's Euro runs largely averaged out and adjusted for biases, here's my rough SOI projections for the next 10 days:
    6/11: -26
    6/12: -28
    6/13: -9
    6/14: +1
    6/15: 0
    6/16: -7
    6/17: -13
    6/18: -17
    6/19: -13
    6/20: -9

    Based on this, I'm guessing the 6/1-20 SOI will be near -8 and will mean June as a whole has a pretty high chance to end up negative and a pretty good chance to end up sub -5. That would be pretty supportive of a later in the year weak to low end moderate El Nino based on history back to the late 1800s and especially when considering the subsurface now being near or warmer than +1.0.

    I'm projecting Tahiti to be in or near the 1014-1014.25 range and Darwin to be in or near the 1014.3-1014.7 range for 6/1-20. Consider these stats:

    Avg June Darwin SLP minus 1000: 13.0
    Avg June Tahiti SLP minus 1000: 13.7

    Avg June Darwin SLP minus 1000 strong Nino: 13.5
    Avg June Darwin SLP minus 1000 wk-mod Nino: 13.0
    Avg June Darwin SLP minus 1000 weak Nina: 13.0
    Avg June Darwin SLP minus 1000 mod-str Nina: 12.8

    Avg June Tahiti SLP minus 1000 strong Nino: 12.8
    Avg June Tahiti SLP minus 1000 wk-mod Nino: 13.5
    Avg June Tahiti SLP minus 1000 weak Nina: 14.2
    Avg June Tahiti SLP minus 1000 mod-str Nina: 14.1

    So, the Darwin SLP appears on the way to above normal for June with Tahiti slightly above. Actually, there have been only 3 Junes with Darwin SLP higher than 1014 mb since 1950: 2004 (preceded weak El Nino), 1997 (preceded SEN), and 1965 (preceded SEN). So, Darwin, alone, favors El Nino.

    Have there been any Tahiti Junes in the high 1013s or higher that preceded El Nino? Actually, there have been a pretty good number but mainly weak: 1965 SEN (1013.7), 1968 MEN (1014.9), 1969 WEN (1013.8), 1976 WEN (1013.8), 1979 WEN (1014.5), 1991 SEN (1013.8), 2004 WEN (1013.7), and 2006 WEN (1013.8).

    Conclusion: I'm leaning toward a late oncoming (after ASO in deference to the Eurosip May Nino 3.4 forecast for ASO being only warm neutral) weak to low end moderate El Nino this year.

    *Edit: The 6/11 daily SOI should have been released by now. Maybe they're on vacation.
     
    Last edited: Jun 11, 2018
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  23. Snowfan

    Snowfan Member

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    Nino 3.4 warmed to 0.2 C. And CPC issued a El Niño Watch.
     
  24. GaWx

    GaWx Supporter Member

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    Thanks. However, note that despite the 0.2 warming in Niño 3.4, the upper OHC actually cooled a bit to +0.82 after having been near +1.0 in late May. So, perhaps that means any further warming over the next couple of months will be slow overall. I’m still thinking only warm neutral for ASO (based largely on the warm biased May Eurosip being only at warm neutral for ASO) followed by warming to weak to low end moderate El Niño later in fall to winter.
     
  25. Webberweather53

    Webberweather53 Meteorologist

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    It was hardly above +0.9 and barely dropped to +0.8, we had a larger drop in April and that really didn't mean much. It's not going to make that much of a difference in the grand scheme of things, I wouldn't delve too much into it, especially when there's been more WWBs.
    heat-last-year.gif
     
  26. GaWx

    GaWx Supporter Member

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    Eric,
    The OHC graph within the 6/4/18 report did actually show near +1.0 as per this post:
    http://southernwx.com/community/threads/enso-updates.146/page-16#post-101602

    CPC has since cooled it back some for that period in each of the subsequent two weekly releases, but it was showing near +1.0 then.

    Regardless of exactly how much it has cooled back, it has cooled a small amount and I'm sticking with my prediction that the ASO trimonth will be warm neutral (cooler than +0.5) based largely on the May Eurosip being only warm neutral for ASO. During 2005-17 it never missed a category to the cool side. The average miss was a whopping +0.5, a very significant warm bias. I'm expecting ONI based El Nino to start during the SON trimonth or later.

    What are you predicting for the ASO trimonth for Nino 3.4?

    Regardless of my prediction of only warm neutral for ASO, I still expect the tropics to be affected negatively by the anticipated oncoming El Nino
     
  27. Webberweather53

    Webberweather53 Meteorologist

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    Where are you getting +1.01C from because it’s not listed in the CPCs weekly report? If you're just eyeballing it then that doesn't count, it certainly seems to have barely ticked above +0.9C. Regardless you have to keep in mind that the GODAS analysis the CPC uses is often much different than the actual data provided by the TAO buoys, a change of a tenth or two degrees C is well within the understood error range of this product. I think you’re overreacting to this apparent downturn in OHC.
     
    Last edited: Jun 19, 2018
  28. Webberweather53

    Webberweather53 Meteorologist

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    A quarter to a third of degree C (0.33) is well within the understood error range for this product, you only have to look so far as to other ocean models published by ECMWF, JMA, and the BOM to see that this apparent change in the CPC's GODAS product isn't significant or arguably even measurable.
    [​IMG]
    [​IMG]
     
  29. GaWx

    GaWx Supporter Member

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    Yes, it was eyeballing. Also, it actually was showing warmer (near +1.0) in the 6/4 report though the 6/11 report wasn't quite as warm and the 6/18 report was even a little cooler.For whatever reason, they often modify earlier periods.

    It is Eurosip that is what I had last month based my ASO prediction on. At the time, OHC was rising toward new seasonal highs. The recent slight OHC cooldown came well after that prediction.
    What are you predicting for ASO?
     
  30. NCSNOW

    NCSNOW Member

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    [​IMG]
    HOME> Outlook Maps>Seasonal Forecast Discussion

    PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
    NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
    830 AM EDT THU JUN 21 2018

    SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS

    THE JULY-AUGUST-SEPTEMBER (JAS) 2018 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL
    TEMPERATURES ACROSS A MAJORITY OF THE FORECAST DOMAIN, ALTHOUGH EQUAL CHANCES
    OF BELOW-, NEAR-, OR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE NORTHERN
    GREAT PLAINS AND UPPER MISSISSIPPI VALLEY. THE HIGHEST PROBABILITIES FOR
    ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS PARTS OF THE GREAT BASIN AND
    PACIFIC NORTHWEST. THE JAS 2018 PRECIPITATION OUTLOOK FEATURES ENHANCED ODDS
    FOR ABOVE NORMAL PRECIPITATION ACROSS THE MID-ATLANTIC AND EXTENDING FROM
    SOUTHERN CALIFORNIA AND THE DESERT SOUTHWEST NORTHEAST TO THE GREAT BASIN AND
    CENTRAL ROCKIES. INCREASED CHANCES FOR ABOVE NORMAL PRECIPITATION ARE ALSO
    FORECAST ACROSS MAINLAND ALASKA AND THE ALEUTIANS. BELOW-NORMAL PRECIPITATION
    IS FAVORED ACROSS THE WESTERN GULF COAST, LOWER MISSISSIPPI VALLEY, AND PACIFIC
    NORTHWEST.

    DURING THE FALL AND WINTER 2018-19, THE TEMPERATURE AND PRECIPITATION OUTLOOKS
    ARE CONSISTENT WITH INCREASING ODDS OF EL NINO DEVELOPMENT AND ITS TYPICAL
    INFLUENCES. CHANCES FOR ABOVE NORMAL PRECIPITATION HAVE INCREASED ACROSS THE
    SOUTHERN TIER OF THE CONUS, COMPARED TO PREVIOUS OUTLOOKS. ODDS FOR ABOVE
    NORMAL TEMPERATURES CONTINUE TO INCREASE DURING THE WINTER 2018-19, FROM THE
    PACIFIC NORTHWEST EAST TO THE NORTHERN GREAT PLAINS AND UPPER MISSISSIPPI
    VALLEY.

    EQUAL CHANCES (EC) ARE FORECAST IN AREAS WHERE THE LIKELIHOOD OF SEASONAL MEAN
    TEMPERATURES OR SEASONAL ACCUMULATED PRECIPITATION AMOUNTS ARE EXPECTED TO BE
    SIMILAR TO CLIMATOLOGICAL PROBABILITIES.

    BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS
    NOTE: FOR GRAPHICAL DISPLAYS OF THE FORECAST TOOLS DISCUSSED BELOW SEE:
    HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/TOOLS/BRIEFING

    CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS

    OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC INDICATE
    ENSO-NEUTRAL CONDITIONS PERSISTED THROUGH MAY. THE OBSERVED WEEKLY SSTS,
    CENTERED ON JUNE 13, FEATURE POSITIVE ANOMALIES OF MORE THAN 0.5 DEGREE C FROM
    140-100 DEGREES W AND ALSO WEST OF THE DATE LINE. POSITIVE SUBSURFACE
    TEMPERATURE ANOMALIES (AVERAGED ACROSS 180-100 DEGREES W) CONTINUED TO
    INCREASE, DUE TO ANOTHER DOWNWELLING OCEANIC KELVIN WAVE.

    OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES INDICATED SUPPRESSED CONVECTION
    FROM PAPUA NEW GUINEA EAST TO THE CENTRAL EQUATORIAL PACIFIC OCEAN FROM MAY 18
    TO JUNE 12. THE WIND ANOMALIES AT THE LOWER AND UPPER-LEVELS WERE NEAR AVERAGE
    ACROSS THE EQUATORIAL PACIFIC. THESE ATMOSPHERIC INDICATORS ARE CONSISTENT WITH
    ENSO NEUTRAL CONDITIONS.


    PROGNOSTIC DISCUSSION OF SST FORECASTS

    THE CPC SST CONSOLIDATION (CON) FOR THE NINO 3.4 REGION INDICATES AN INCREASE
    IN ANOMALIES TO +0.5 DEGREES C BY SON WITH POSITIVE ANOMALIES PEAKING CLOSER TO
    1.0 DEGREES C DURING NDJ AND DJF 2018-19. THE SST CONSTRUCTED ANALOG AND MARKOV
    MODEL INDICATE PEAK ANOMALY VALUES GREATER THAN 1.0 C THIS UPCOMING WINTER. THE
    CPC/IRI CONSENSUS FORECAST FAVORS THE ONSET OF EL NINO DURING THE NORTHERN
    HEMISPHERE FALL WITH PROBABILITIES OF EL NINO ABOVE 60 PERCENT FROM NDJ 2018-19
    JFM 2019.

    PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS

    THE INCREASING LIKELIHOOD OF EL NINO DEVELOPMENT CONTINUES TO PLAY A MAJOR
    FACTOR IN THE FALL AND WINTER 2018-19 OUTLOOKS. TOOLS USED FOR THE SEASONAL
    OUTLOOKS INCLUDED DYNAMICAL MODEL FORECAST GUIDANCE SUCH AS THE NORTH AMERICAN
    MULTI-MODEL ENSEMBLE (NMME), THE ENSO-OCN STATISTICAL MODEL, THE SST
    CONSTRUCTED ANALOG MODEL, AND EL NINO COMPOSITES. A RELATIVELY NEW TOOL IN OUR
    SUITE IS THE CBAM TOOL, OR CALIBRATION, BRIDGING, AND MERGING FORECAST TOOL.
    THIS USES A BAYESIAN APPROACH TO THE NMME MODEL CONSOLIDATION AS WELL AS A
    HYBRIDIZATION WHEREIN EACH CONSTITUENT MODEL'S NINO 3.4 FORECAST IS 'BRIDGED'
    TO THE PREDICTAND VIA LINEAR REGRESSION. THE OUTLOOKS DURING THE 2019 WARM
    SEASON WERE BASED PRIMARILY ON DECADAL TRENDS.

    PROGNOSTIC DISCUSSION OF OUTLOOKS - JAS 2018 TO JAS 2019

    TEMPERATURE

    ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE CONUS AND ALASKA DURING
    JAS WITH THE HIGHEST PROBABILITIES FORECAST ACROSS THE GREAT BASIN AND PACIFIC
    NORTHWEST, BASED ON EXCELLENT AGREEMENT AMONG TOOLS INCLUDING A STRONG DECADAL
    SIGNAL. PROBABILITIES FOR ABOVE NORMAL TEMPERATURES WERE REDUCED ACROSS THE
    SOUTHWEST FROM THE PREVIOUS OUTLOOK DUE TO INCREASING FORECAST CONFIDENCE IN A
    WETTER PATTERN. ABOVE NORMAL TEMPERATURES ARE FAVORED TO INCLUDE MORE OF THE
    SOUTH-CENTRAL U.S. DURING JAS, COMPARED TO LAST MONTH, WITH THE CONSIDERATION
    OF LOW SOIL MOISTURE TO START THE OUTLOOK PERIOD ACROSS THE OZARKS REGION, A
    DRIER TREND IN THE SEASONAL TOOLS, AND CONSISTENCY WITH THE JULY TEMPERATURE
    OUTLOOK. ALSO, THE IMME INDICATES POSITIVE TEMPERATURES ANOMALIES FOR THE
    MIDDLE MISSISSIPPI VALLEY DURING THIS TIME PERIOD. EQUAL CHANCES FOR BELOW-,
    NEAR-, OR ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR THE NORTHERN GREAT PLAINS
    AND UPPER MISSISSIPPI VALLEY WHERE FORECAST CONFIDENCE IS LOWEST.

    THE INCREASING CHANCES FOR EL NINO DEVELOPMENT WERE A FACTOR IN THE TEMPERATURE
    OUTLOOK, BEGINNING IN THE FALL AND BECOMING MORE PROMINENT DURING THE WINTER
    2018-19. BASED ON EL NINO COMPOSITES, PROBABILITIES FOR ABOVE NORMAL
    TEMPERATURES WERE INCREASED ACROSS MUCH OF MAINLAND ALASKA AND ALONG THE
    NORTHERN TIER OF THE CONUS WITH A DECREASE IN THE COVERAGE OF ABOVE NORMAL
    TEMPERATURES THROUGHOUT THE SOUTHERN TIER OF THE CONUS. AN EXPECTED LACK OF SEA
    ICE ELEVATES CHANCES FOR ABOVE NORMAL TEMPERATURES ACROSS NORTHERN ALASKA
    DURING THE FALL SEASON. THE TEMPERATURE OUTLOOK AT THE LONGER LEAD TIMES IS
    BASED LARGELY ON TRENDS.

    PRECIPITATION

    THE PRECIPITATION OUTLOOKS ARE BASED ON THE LATEST DYNAMICAL MODEL GUIDANCE,
    THROUGH NDJ, ALONG WITH THE TYPICAL INFLUENCES FROM EL NINO DURING THE FALL AND
    WINTER 2018-19. COMPARED TO THE PREVIOUS OUTLOOK FOR JAS, ODDS FOR ABOVE NORMAL
    PRECIPITATION WERE EXPANDED TO INCLUDE MORE OF THE DESERT SOUTHWEST AND
    SOUTHERN CALIFORNIA. THIS IS CONSISTENT WITH THE NMME AND POTENTIAL RAINFALL
    ASSOCIATED WITH EAST PACIFIC TROPICAL CYCLONES, WHICH ARE MORE LIKELY TO AFFECT
    THESE AREAS DURING A DEVELOPING EL NINO. THE LATEST PRECIPITATION TOOLS,
    INDICATE LITTLE TO NO SUPPORT FOR THE INCREASED CHANCES OF BELOW NORMAL
    PRECIPITATION FOR FLORIDA, SO THAT WAS REMOVED FROM THE PREVIOUS OUTLOOK. THE
    NMME INDICATES RELATIVELY HIGH ODDS FOR BELOW NORMAL PRECIPITATION EXTENDING
    FROM THE CARIBBEAN REGION WEST TO THE GULF OF MEXICO AND MUCH OF TEXAS AND THE
    LOWER MISSISSIPPI VALLEY. THEREFORE, INCREASED CHANCES FOR BELOW NORMAL
    PRECIPITATION WERE INTRODUCED TO PARTS OF TEXAS AND THE LOWER MISSISSIPPI
    VALLEY FOR JAS. PRECIPITATION TOOLS REMAINED CONSISTENT FEATURING ENHANCED ODDS
    FOR ABOVE (BELOW) NORMAL PRECIPITATION ACROSS PARTS OF THE EASTERN U.S.
    (PACIFIC NORTHWEST) AND A RELATIVELY WET PATTERN FOR MUCH OF ALASKA.

    EL NINO PRECIPITATION COMPOSITES WERE RELIED UPON IN THE OUTLOOKS DURING THE
    FALL AND WINTER SEASONS WHEN ABOVE-NORMAL PRECIPITATION BECOMES MORE LIKELY
    ACROSS THE SOUTHWEST, SOUTHERN GREAT PLAINS, GULF COAST STATES, AND SOUTHEAST.
    THE STRONGEST WET SIGNAL EXISTS ACROSS FLORIDA DURING NDJ AND DJF, WHILE A DRY
    SIGNAL EXISTS FROM THE GREAT LAKES SOUTH TO THE OHIO VALLEY DURING JFM AND FMA.
    THE PRECIPITATION OUTLOOK ACROSS ALASKA DURING THE FALL AND WINTER IS
    CONSISTENT WITH THE SST CONSTRUCTED ANALOG.

    AT THE LONGER LEADS, MJJ THROUGH JAS 2019, THE TILT IN THE ODDS TOWARDS ABOVE
    NORMAL PRECIPITATION ACROSS PARTS OF THE CENTRAL AND EASTERN U.S. IS CONSISTENT
    WITH TRENDS. ALSO, THE FAVORED AREA FOR BELOW-MEDIAN PRECIPITATION ACROSS THE
    NORTHWESTERN CONUS DURING THESE OUTLOOK PERIODS IS RELATED TO TRENDS.

    FORECASTER: BRAD PUGH

    THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, FOLLOWING
    THE WORLD METEROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3
    COMPLETE DECADES AS THE CLIMATIC REFERENCE PERIOD. THE PROBABILITY ANOMALIES
    FOR TEMPERATURE AND PRECIPITATION BASED ON THESE NEW NORMALS BETTER REPRESENT
    SHORTER TERM CLIMATIC ANOMALIES THAN THE FORECASTS BASED ON OLDER NORMALS.

    FOR A DESCRIPTION OF OF THE STANDARD FORECAST TOOLS - THEIR SKILL- AND THE
    FORECAST FORMAT PLEASE SEE OUR WEB PAGE AT
    HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/LONG_RANGE/TOOLS.HTML
    (USE LOWER CASE LETTERS)
    INFORMATION ON THE FORMATION OF SKILL OF THE CAS FORECASTS MAY BE FOUND AT:
    HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US/OUTLOOK/OUTLOOK.SHTM
    L
    (USE LOWERCASE LETTERS)
    NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR
    VALID PERIOD. WITHIN ANY GIVEN VALID PERIOD OBSERVATIONS AND SHORT AND MEDIUM
    RANGE FORECASTS SHOULD BE CONSULTED.

    THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT
    MONTH ON JUL 19 2018


    1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE W
     

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