Things are looking up.
Eastern North Pacific high- and low-activity eras
In addition to year-to-year fluctuations, eastern Pacific hurricane activity exhibits strong variability on decadal and multi-decadal time scales. Periods of increased activity (such as 1982-94 and 2014-19) are called high-activity eras, and periods of decreased activity (such as 1971-1981 and 1995-2013) are called low-activity eras. The differences in seasonal activity between these two eras are considerable. High-activity eras average about 4.6 more named storms, 3.1 more hurricanes, 2.4 more major hurricanes, and 59 more ACE points, than low-activity eras. As a result, above-normal seasons occur about three times more frequently during high-activity eras (63% of seasons compared to 20%), and below-normal seasons are about four times less frequent (11% compared to 43%).
High- and low-activity eras are strongly related to global patterns of SST anomalies. It is upon these patterns that the inter-annual ENSO signal overlays. One such pattern is called the Pacific Decadal Oscillation (PDO). The PDO spans most of the North Pacific Ocean, and is associated with decadal fluctuations in hurricane activity. The positive (negative) phase of the PDO tends to be associated with high- (low-) activity eras. Another global SST pattern is the AMO. The cold (warm) phase of the AMO increases the likelihood of a high- (low-) activity era. The AMO helps to explain the inverse relationship in activity between the eastern Pacific and Atlantic basin, with a warm AMO favoring increased Atlantic activity and decreased eastern Pacific activity.
Looking at combinations of the AMO and PDO, the 1982-94 high-activity era was associated with a cold AMO and a positive PDO, while the 2014-19 high-activity era primarily featured a strong positive PDO. Conversely, the intervening 1995-2013 low-activity era featured a warm AMO and negative PDO.
Regarding 2020, the current and predicted SST anomalies reflect the ongoing warm phase of the AMO, which has been present since 1995. They also reflect near- or below-average SSTs across the eastern Pacific hurricane region, which projects onto the negative phase of the PDO. This PDO signal is in marked contrast to the exceptionally warm SSTs and positive PDO seen in the eastern Pacific during the recent 2014-19 high-activity era.
Confidence is not high that the negative PDO pattern will persist through the hurricane season. One reason is that SST forecasts made several months ahead tend to have limited skill. Another reason is that the current negative PDO signal partly reflects the synoptic-scale wind and pressure patterns associated with a highly-amplified High pressure system over the middle latitudes of the North Pacific. Therefore, the current conditions are not necessarily a longer-term transition to the negative PDO. These observations lead to larger uncertainty about the nature of the background climate signal upon which the ENSO signal will overlay during the peak months of the 2020 eastern Pacific hurricane season.
A closer look at ENSO during high- and low-activity eras
High- and low-activity era averages vary with ENSO phase, as seen for JAS Nino 3.4 SST anomalies ≤ -0.75°C, within ± 0.75°C, and ≥ 0.75°C. Although these ranges differ slightly from the official NOAA ENSO classifications, they are used to better isolate stronger El Niño and La Niña episodes from the weakest ones.
During high-activity eras, the highest levels of seasonal activity are seen for ENSO-neutral and El Niño years. These averages include 18-19 named storms, roughly 10-11 hurricanes, 6 major hurricanes, and an ACE between 135%-155% of the median. Consistent with these numbers, above-normal (near-normal) seasons are recorded in two-thirds (about 30%) of cases for both El Niño and ENSO-neutral. In contrast, for the single La Niña year in the high-activity era record, the seasonal activity included 13 named storms, 6 hurricanes, 1 major hurricane, and an ACE of 78% of median, all of which are well below the El Niño and ENSO-neutral averages.
During low-activity eras, the most major hurricanes (5) and highest ACE values (119% of median) on average are seen during El Niño years, and the fewest (roughly 3 major hurricanes and ACE of 80%-90% of the median) are seen for both La Niña and ENSO-neutral. The fewest named storms (12.4) and hurricanes (7.0) are seen during La Niña, with only slightly higher averages (14 named storms and 7.7 hurricanes) during both ENSO-neutral and El Niño.
For all parameters, the largest decreases during low-activity eras are seen for ENSO-neutral years, with average decreases of 4.5 named storms, 3 hurricanes, 3 major hurricanes, and 71 ACE points. El Niño years feature similar large decreases in both named storms and hurricanes, but only slight decreases in major hurricanes (0.7) and ACE (16 points).
During El Niño, the probabilities of above-normal (33%) and near-normal (67%) seasons during low-activity eras are essentially reversed compared to high-activity eras. For ENSO-neutral, the probability of an above-normal season drops sharply to near 15% during low-activity eras, and the probability of a below-normal season increases to near 50%. As a result, La Niña and ENSO-neutral have roughly similar probabilities for all three season classifications during low-activity eras.
Looking specifically at the seasonal activity that is historically associated with the predicted Niño 3.4 conditions for this season, the results are again highly dependent on whether the eastern Pacific is in a high-activity era or a low-activity era. If the negative PDO signal persists, the average activity would be about 14 named storms, 8 hurricanes, 3 major hurricanes, and an ACE of 82% of median. In contrast, if the positive PDO signal returns, the averages would increase to almost 20 named storms, 11-12 hurricanes, 6 major hurricanes, and an ACE of 160% of median. These analogues highlight the uncertainty in this hurricane outlook, which arises primarily because of uncertainty in predictions of the PDO and ENSO. The predicted ranges of activity for 2020 are designed to capture not only the predicted conditions, but also their uncertainty.
In summary; look for a slower than average hurricane season UNLESS water temps warm up slightly between Mexico and Hawaii resulting in an era of ‘high activity’. We can only hope.
SURF:
As we go flying through springtime, it's good to see the sun, beaches open, clean water, and surf finally.
This past week had a mixed bag with solid surf if you could find a window between the wind. All in all there was waves, the red tide dissipated, and it's good to be on track again. For Friday, we've got another weak cold front moving by to the N and we'll just get breezy conditions down here for Friday. Look for more chest high bumpy sets from the NW with a touch of SW underneath. Saturday the NW windswell peaks with shoulder high sets and cleaner conditions while Sunday drops to the chest high range from the combo swells. As far as the sun/water temps/tides go, here's what you need to know:
- Sunrise and sunset are:
- 5:45 AM sunrise
- 7:45 PM sunset
- Water temps in N County have dropped if you didn't notice due to all the WNW wind this week. We literally went from 70 last weekend to 60 this weekend. We should though rebound to the mid-60's mid-week once high pressure sets up again.
- And tides are all over the place the next few days:
- almost -1' at sunrise
- 3.5' before lunch
- 2' mid-afternoon
- up to 5' at sunset
FORECAST:
For Memorial Day, we have new SW swell showing up to keep us in the chest high range. The storms in the southern hemisphere this past weren't that organized but they did have a lot of wind. Look for the SW to slowly build during the week for shoulder high surf by Wednesday and smaller NW windswell during the 1st half of the week.
We get a little break late next week but still rideable from the SW then more shoulder high sets next weekend.
After that, it looks to be more disorganized surf headed our way from the southern hemisphere and shoulder high surf again around June 4th. In a nutshell- nothing big the next 2 weeks but plenty of fun surf.
BEST BET:
Saturday with clean NW windswell. Or Monday-Wednesday with new chest high SW. Or next weekend with more SW. Or June 4th with more SW...
WEATHER:
Even though we've had some windy days lately, I'll take that over May Gray any day. Jinx! (more on that later). For Friday, we've got a weak cold front moving by to the N which won't give us any clouds but it will give us more WNW wind. Look for it to be messy tomorrow with gusts close to 20 mph. Saturday and Sunday look nice with just a return of low clouds/fog in the nights/mornings. For next week, high pressure is in charge. While the deserts hit over 100, the coast will be a mild 70 with the fog lingering near the beaches all day unfortunately. Welcome back May Gray. Make sure to check out Twitter/North County Surf if anything changes between now and then.
NEWS OF THE WEEK:
The National Oceanic and Atmospheric Administration has released their annual Eastern Pacific Hurricane outlook and…
NOAA’s 2020 eastern Pacific Hurricane Season Outlook indicates a near- or below-normal season most likely (75% combined chance). There is a 40% chance of a near-normal season and a 35% chance of a below-normal season, followed by a 25% chance of an above-normal season. The eastern Pacific hurricane region covers the eastern North Pacific Ocean east of 140°W north of the equator.
The 2020 outlook calls for a 70% probability for each of the following ranges of activity:
• 11-18 Named Storms
• 5-10 Hurricanes
• 1-5 Major Hurricanes
• Accumulated Cyclone Energy (ACE) range of 60%-135% of the median.
The activity is expected to fall within these ranges in 70% of seasons with similar climate conditions and uncertainties to those expected this year. These ranges do not represent the total possible activity seen in past similar years. The predicted ranges are centered slightly below the 1981-2010 averages of 15 named storms, 8 hurricanes, and 4 major hurricanes. The eastern Pacific hurricane season officially runs from May 15th through November 30th. The peak months of the season are July-September (JAS).
Reasoning behind the outlook
Two climate factors are expected to contribute to a near- or below-normal 2020 hurricane season across the eastern (and central) Pacific hurricane basins, as follows:
1) The current and predicted SST anomaly patterns indicate below- or near-average SSTs across the eastern Pacific hurricane region, and above-average SSTs across the Atlantic Main Development Region (MDR). Historically, this combination tends to be associated with near- or below-normal hurricane activity.
2) The most recent forecast from the NOAA Climate Prediction Center indicates a likely continuation of ENSO-neutral conditions (i.e., no El Niño or La Niña), or even the development of La Niña. The ENSO influence on eastern Pacific hurricane activity is highly dependent upon the background SST patterns across the eastern Pacific hurricane region and the Atlantic MDR. For the SST anomaly patterns above, both ENSO-neutral and La Niña tend to favor reduced eastern Pacific hurricane activity, often resulting in a near- or below-normal hurricane season.
a. ENSO-neutral or La Niña most likely
ENSO-neutral conditions are present. The latest weekly SSTs are near average across the central and eastern equatorial Pacific, and the SST index for the Niño 3.4 region is -0.3°C. The Niño 3.4 region spans the east-central equatorial Pacific between 120°W-170°W and 5°N-5°S.
The Niño 3.4 index has recently cooled considerably. Previously this index was above +0.5°C during October 2019 through late April 2020. However, important El Niño impacts had been largely absent, which is why the CPC did not declare an El Niño. [NOAA classifies a weak El Niño as having a sustained Niño 3.4 index between +0.5°C and +1.0°C, along with consistent atmospheric impacts.] For example, during March-April 2020 convection was suppressed across the east-central and eastern equatorial Pacific Ocean, and the upper tropospheric circulation at 200-hPa featured enhanced mid-Pacific troughs in the subtropics of both hemispheres. Also, the easterly trade winds were stronger-than-average across the equatorial Pacific. None of these conditions reflect an El Niño, which by comparison would feature enhanced equatorial convection east of the date line, along with weaker mid-Pacific troughs at 200-hPa and westerly wind anomalies at 850-hPa.
Looking forward, model predicted SST anomalies in the Niño 3.4 region generally indicate ENSO-neutral (Niño 3.4 index between ± 0.5°C) throughout the hurricane season. The dynamical model average (red line) is on the cool side of zero, while the statistical model average (green line) is on the warm side of zero.
However, some of the dynamical models are indicating a transition to La Niña (Niño 3.4 index ≤ -0.5°C) as the summer progresses, which appears to be consistent with the enhanced trade winds and the recent decrease in SST anomalies across the equatorial Pacific Ocean. NOAA’s Climate Forecast system (CFS) is predicting La Niña during ASO 2020.
Based on current conditions, the recent oceanic evolution, model forecasts, and the low skill inherent in ENSO predictions made at this time of the year, NOAA’s latest ENSO outlook indicates about a 55% chance of ENSO-neutral during JAS and August-October (ASO), followed by a 35% chance of La Niña and only a 10% chance of El Niño.
An important measure of the total seasonal activity is NOAA’s Accumulated Cyclone Energy (ACE) index, which accounts for the combined intensity and duration of named storms and hurricanes during the season. This 2020 outlook indicates a 70% chance that the ACE range will be 60%-135% of the median. An ACE value of 80%-115% of the median indicates a near-normal season. Values above this range reflect an above-normal season, and values below this range reflect a below-normal season.
NOAA’s 2020 eastern Pacific Hurricane Season Outlook indicates a near- or below-normal season most likely (75% combined chance). There is a 40% chance of a near-normal season and a 35% chance of a below-normal season, followed by a 25% chance of an above-normal season. The eastern Pacific hurricane region covers the eastern North Pacific Ocean east of 140°W north of the equator.
The 2020 outlook calls for a 70% probability for each of the following ranges of activity:
• 11-18 Named Storms
• 5-10 Hurricanes
• 1-5 Major Hurricanes
• Accumulated Cyclone Energy (ACE) range of 60%-135% of the median.
The activity is expected to fall within these ranges in 70% of seasons with similar climate conditions and uncertainties to those expected this year. These ranges do not represent the total possible activity seen in past similar years. The predicted ranges are centered slightly below the 1981-2010 averages of 15 named storms, 8 hurricanes, and 4 major hurricanes. The eastern Pacific hurricane season officially runs from May 15th through November 30th. The peak months of the season are July-September (JAS).
Reasoning behind the outlook
Two climate factors are expected to contribute to a near- or below-normal 2020 hurricane season across the eastern (and central) Pacific hurricane basins, as follows:
1) The current and predicted SST anomaly patterns indicate below- or near-average SSTs across the eastern Pacific hurricane region, and above-average SSTs across the Atlantic Main Development Region (MDR). Historically, this combination tends to be associated with near- or below-normal hurricane activity.
2) The most recent forecast from the NOAA Climate Prediction Center indicates a likely continuation of ENSO-neutral conditions (i.e., no El Niño or La Niña), or even the development of La Niña. The ENSO influence on eastern Pacific hurricane activity is highly dependent upon the background SST patterns across the eastern Pacific hurricane region and the Atlantic MDR. For the SST anomaly patterns above, both ENSO-neutral and La Niña tend to favor reduced eastern Pacific hurricane activity, often resulting in a near- or below-normal hurricane season.
a. ENSO-neutral or La Niña most likely
ENSO-neutral conditions are present. The latest weekly SSTs are near average across the central and eastern equatorial Pacific, and the SST index for the Niño 3.4 region is -0.3°C. The Niño 3.4 region spans the east-central equatorial Pacific between 120°W-170°W and 5°N-5°S.
The Niño 3.4 index has recently cooled considerably. Previously this index was above +0.5°C during October 2019 through late April 2020. However, important El Niño impacts had been largely absent, which is why the CPC did not declare an El Niño. [NOAA classifies a weak El Niño as having a sustained Niño 3.4 index between +0.5°C and +1.0°C, along with consistent atmospheric impacts.] For example, during March-April 2020 convection was suppressed across the east-central and eastern equatorial Pacific Ocean, and the upper tropospheric circulation at 200-hPa featured enhanced mid-Pacific troughs in the subtropics of both hemispheres. Also, the easterly trade winds were stronger-than-average across the equatorial Pacific. None of these conditions reflect an El Niño, which by comparison would feature enhanced equatorial convection east of the date line, along with weaker mid-Pacific troughs at 200-hPa and westerly wind anomalies at 850-hPa.
Looking forward, model predicted SST anomalies in the Niño 3.4 region generally indicate ENSO-neutral (Niño 3.4 index between ± 0.5°C) throughout the hurricane season. The dynamical model average (red line) is on the cool side of zero, while the statistical model average (green line) is on the warm side of zero.
However, some of the dynamical models are indicating a transition to La Niña (Niño 3.4 index ≤ -0.5°C) as the summer progresses, which appears to be consistent with the enhanced trade winds and the recent decrease in SST anomalies across the equatorial Pacific Ocean. NOAA’s Climate Forecast system (CFS) is predicting La Niña during ASO 2020.
Based on current conditions, the recent oceanic evolution, model forecasts, and the low skill inherent in ENSO predictions made at this time of the year, NOAA’s latest ENSO outlook indicates about a 55% chance of ENSO-neutral during JAS and August-October (ASO), followed by a 35% chance of La Niña and only a 10% chance of El Niño.
An important measure of the total seasonal activity is NOAA’s Accumulated Cyclone Energy (ACE) index, which accounts for the combined intensity and duration of named storms and hurricanes during the season. This 2020 outlook indicates a 70% chance that the ACE range will be 60%-135% of the median. An ACE value of 80%-115% of the median indicates a near-normal season. Values above this range reflect an above-normal season, and values below this range reflect a below-normal season.
Eastern North Pacific high- and low-activity eras
In addition to year-to-year fluctuations, eastern Pacific hurricane activity exhibits strong variability on decadal and multi-decadal time scales. Periods of increased activity (such as 1982-94 and 2014-19) are called high-activity eras, and periods of decreased activity (such as 1971-1981 and 1995-2013) are called low-activity eras. The differences in seasonal activity between these two eras are considerable. High-activity eras average about 4.6 more named storms, 3.1 more hurricanes, 2.4 more major hurricanes, and 59 more ACE points, than low-activity eras. As a result, above-normal seasons occur about three times more frequently during high-activity eras (63% of seasons compared to 20%), and below-normal seasons are about four times less frequent (11% compared to 43%).
High- and low-activity eras are strongly related to global patterns of SST anomalies. It is upon these patterns that the inter-annual ENSO signal overlays. One such pattern is called the Pacific Decadal Oscillation (PDO). The PDO spans most of the North Pacific Ocean, and is associated with decadal fluctuations in hurricane activity. The positive (negative) phase of the PDO tends to be associated with high- (low-) activity eras. Another global SST pattern is the AMO. The cold (warm) phase of the AMO increases the likelihood of a high- (low-) activity era. The AMO helps to explain the inverse relationship in activity between the eastern Pacific and Atlantic basin, with a warm AMO favoring increased Atlantic activity and decreased eastern Pacific activity.
Looking at combinations of the AMO and PDO, the 1982-94 high-activity era was associated with a cold AMO and a positive PDO, while the 2014-19 high-activity era primarily featured a strong positive PDO. Conversely, the intervening 1995-2013 low-activity era featured a warm AMO and negative PDO.
Regarding 2020, the current and predicted SST anomalies reflect the ongoing warm phase of the AMO, which has been present since 1995. They also reflect near- or below-average SSTs across the eastern Pacific hurricane region, which projects onto the negative phase of the PDO. This PDO signal is in marked contrast to the exceptionally warm SSTs and positive PDO seen in the eastern Pacific during the recent 2014-19 high-activity era.
Confidence is not high that the negative PDO pattern will persist through the hurricane season. One reason is that SST forecasts made several months ahead tend to have limited skill. Another reason is that the current negative PDO signal partly reflects the synoptic-scale wind and pressure patterns associated with a highly-amplified High pressure system over the middle latitudes of the North Pacific. Therefore, the current conditions are not necessarily a longer-term transition to the negative PDO. These observations lead to larger uncertainty about the nature of the background climate signal upon which the ENSO signal will overlay during the peak months of the 2020 eastern Pacific hurricane season.
A closer look at ENSO during high- and low-activity eras
High- and low-activity era averages vary with ENSO phase, as seen for JAS Nino 3.4 SST anomalies ≤ -0.75°C, within ± 0.75°C, and ≥ 0.75°C. Although these ranges differ slightly from the official NOAA ENSO classifications, they are used to better isolate stronger El Niño and La Niña episodes from the weakest ones.
During high-activity eras, the highest levels of seasonal activity are seen for ENSO-neutral and El Niño years. These averages include 18-19 named storms, roughly 10-11 hurricanes, 6 major hurricanes, and an ACE between 135%-155% of the median. Consistent with these numbers, above-normal (near-normal) seasons are recorded in two-thirds (about 30%) of cases for both El Niño and ENSO-neutral. In contrast, for the single La Niña year in the high-activity era record, the seasonal activity included 13 named storms, 6 hurricanes, 1 major hurricane, and an ACE of 78% of median, all of which are well below the El Niño and ENSO-neutral averages.
During low-activity eras, the most major hurricanes (5) and highest ACE values (119% of median) on average are seen during El Niño years, and the fewest (roughly 3 major hurricanes and ACE of 80%-90% of the median) are seen for both La Niña and ENSO-neutral. The fewest named storms (12.4) and hurricanes (7.0) are seen during La Niña, with only slightly higher averages (14 named storms and 7.7 hurricanes) during both ENSO-neutral and El Niño.
For all parameters, the largest decreases during low-activity eras are seen for ENSO-neutral years, with average decreases of 4.5 named storms, 3 hurricanes, 3 major hurricanes, and 71 ACE points. El Niño years feature similar large decreases in both named storms and hurricanes, but only slight decreases in major hurricanes (0.7) and ACE (16 points).
During El Niño, the probabilities of above-normal (33%) and near-normal (67%) seasons during low-activity eras are essentially reversed compared to high-activity eras. For ENSO-neutral, the probability of an above-normal season drops sharply to near 15% during low-activity eras, and the probability of a below-normal season increases to near 50%. As a result, La Niña and ENSO-neutral have roughly similar probabilities for all three season classifications during low-activity eras.
Looking specifically at the seasonal activity that is historically associated with the predicted Niño 3.4 conditions for this season, the results are again highly dependent on whether the eastern Pacific is in a high-activity era or a low-activity era. If the negative PDO signal persists, the average activity would be about 14 named storms, 8 hurricanes, 3 major hurricanes, and an ACE of 82% of median. In contrast, if the positive PDO signal returns, the averages would increase to almost 20 named storms, 11-12 hurricanes, 6 major hurricanes, and an ACE of 160% of median. These analogues highlight the uncertainty in this hurricane outlook, which arises primarily because of uncertainty in predictions of the PDO and ENSO. The predicted ranges of activity for 2020 are designed to capture not only the predicted conditions, but also their uncertainty.
In summary; look for a slower than average hurricane season UNLESS water temps warm up slightly between Mexico and Hawaii resulting in an era of ‘high activity’. We can only hope.
PIC OF THE WEEK:
Keep Surfing,
Michael W. Glenn
Handsome In 48 Languages
Was Known As Error Jordan On My Junior High Basketball Team
Giving The QS One Last Shot At Age 50
