PAGASA-DOSTPresscon - 04 October 2010

Amihan Conference Room

Weekly averaged sea surface temperatures (left, °C) and anomalies (right, °C) for the past twelve weeks.  SST analysis is the optimum interpolation (OI) analysis, while anomalies are departures from the adjusted OI climatology (Reynolds and Smith 1995, J. Climate, 8, 1571-1583).

Period: 07 July – 22 Sep 2010

SST: Oceanic Indicator:

SOI is above La Niña thresholds

The SOI has remained firmly positive and fairly steady in value for the past two weeks. The latest (27 September) 30-day SOI value was +25; the monthly value for August was +19. The SOI has been consistently positive since early April. Source: BOM, Australia

SOI: Atmospheric Indicator:

NOAA Operational Definitions for El Niño and La Niña

El Niño: characterized by a positive ONI greater than or equal to +0.5°C.

La Niña: characterized by a negative ONI less than or equal to -0.5°C.

By historical standards, to be classified as a full-fledged El Niño or La Niña episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.

CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 SST departures meet or exceed +/- 0.5°C along with consistent atmospheric features. These anomalies must also be forecasted to persist for 3 consecutive months.

ONI (Oceanic Niño Index)

Red – El NiñoBlue – La NiñaBlack - Neutral

International Prediction Centers SummaryClimate Prediction Center / NCEPAs of : 27 Sept 2010

La Niña conditions are present across the equatorial Pacific and is expected to last at least through the NH winter (DJF) 2010-11.

Global Global AdvisoriesAdvisories

International Research Institute (IRI), Columbia University, New YorkAs of : 16 September 2010

Probabilities for La Niña conditions continue at 95% or more through the Dec-Feb season of 2010/11, and first drop to below 50% during Apr-June season of 2011.

Bureau of Meteorology (BOM)-Australia As of : 29 Sept. 2010

La Niña remains well-established in the Pacific and is expected to persist into at least early 2011.

APCC, APEC Climate Center,Busan, S. KoreaAs of: 27 Sept. 2010

The sea surface temperature anomalies in the central to eastern tropical Pacific have been colder than normal suggesting the La Nina phase.

Recent ENSO Conditions: (Sept. 2010)

All key indicators of ENSO (cooler than average sea surface temperatures and the persistently stronger than average low-level winds, coupled with above average values of the Southern Oscillation Index (SOI), are at levels typical of La Niña.

• Based on recent trends and model forecasts, La Niña is likely to persist up to the early part of 2011.

Expected Conditions:

July-August-September (JAS) 2010

Actual (mm) % NormalNormal (mm)(1971-2000)

Actual Seasonal Rainfall

September 2010

Actual (mm) % NormalNormal (mm)(1971-2000)

Actual Rainfall for September 2010

Monthly Rainfall (June - September 2010)

Normal (mm) (1971-2000)

FORECAST OCTOBER 2010

Normal (mm) (1971-2000)

FORECAST NOVEMBER 2010

Normal (mm) (1971-2000)

FORECAST DECEMBER 2010

Normal (mm) (1971-2000)

FORECAST OND 2010

PROVINCE PROVINCE

MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAXCORDILLERA ADMINISTRATIVE REGION (CAR) REGION VI (WESTERN VISAYAS)

ABRA 103.3 116.9 143.4 187.1 164.7 169.8 116.9 128.5 AKLAN 123.8 136.4 135.1 139.2 139.6 145.4 130.8 139.7BENGUET 119.9 132.8 120.3 147.8 173.7 193.5 125.5 136.6 ANTIQUE 109.0 134.5 130.5 138.7 130.3 144.4 121.2 138.6IFUGAO 116.3 124.6 123.5 140.7 160.0 174.8 126.5 130.7 CAPIZ 119.6 128.6 126.3 135.4 131.7 143.0 124.9 134.4

KALINGA 107.9 120.9 114.7 127.2 137.4 163.6 121.6 128.7 GUIMARAS 105.8 107.6 120.7 124.2 124.0 125.5 114.3 115.1APAYAO 96.2 108.9 133.6 144.0 151.0 165.9 110.4 123.0 ILOILO 107.1 122.8 121.4 136.2 125.2 137.5 115.8 128.0

MOUNTAIN PROVINCE 114.5 121.0 127.0 152.6 161.0 172.9 125.6 128.6 NEGROS OCCIDENTAL 105.8 115.0 114.1 131.3 113.6 124.6 111.7 118.5REGION I REGION VII (CENTRAL VISAYAS)

ILOCOS NORTE 95.3 109.2 132.5 177.8 158.8 174.2 105.2 123.2 BOHOL 91.7 112.7 86.6 102.3 92.9 105.8 97.4 101.8ILOCOS SUR 105.5 121.5 137.9 199.7 164.3 179.2 118.0 129.4 CEBU 101.0 116.5 98.1 124.0 98.6 117.9 104.2 114.9

LA UNION 117.2 121.4 132.8 156.7 177.4 195.3 123.9 127.1 NEGROS ORIENTAL 105.2 108.8 115.8 130.1 114.0 123.7 111.1 119.1PANGASINAN 107.9 156.6 116.1 158.1 188.9 209.9 116.4 162.5 SIQUIJOR 98.2 103.0 115.5 121.4 116.7 119.3 109.0 113.5

REGION II REGION VIII (EASTERN VISAYAS)BATANES 99.1 104.7 138.5 149.4 47.6 108.0 103.4 115.8 BILIRAN 113.8 117.3 106.7 107.0 110.7 113.6 110.2 111.6CAGAYAN 95.3 111.5 120.5 138.6 119.9 162.0 110.6 124.8 EASTERN SAMAR 97.8 113.4 92.0 104.5 116.0 134.7 107.8 115.7ISABELA 107.9 120.9 114.7 127.2 137.4 163.6 121.6 128.7 LEYTE 107.8 121.0 80.4 107.1 87.1 110.1 97.5 110.5

NUEVA VIZCAYA 120.9 138.5 105.7 125.8 163.8 186.8 128.7 143.3 NORTHERN SAMAR 110.7 123.3 102.2 103.3 114.3 132.0 112.0 116.5QUIRINO 114.6 127.9 107.1 119.0 144.3 169.4 122.7 134.3SAMAR (WESTERN SAMAR)104.3 121.4 102.4 107.7 112.2 127.7 108.4 114.9

REGION III (CENTRAL LUZON) SOUTHERN LEYTE 113.7 122.6 77.2 88.1 85.0 100.2 96.0 101.6BATAAN 112.4 114.5 120.4 127.0 190.7 203.7 123.1 125.2 REGION IX (ZAMBOANGA PENINSULA)

BULACAN 114.5 120.1 109.8 121.7 179.5 206.5 124.8 131.3 ZAMBOANGA DEL NORTE 97.2 106.8 108.4 148.9 120.9 136.9 107.8 125.2NUEVA ECIJA 117.5 165.4 105.0 122.5 179.7 211.3 125.0 171.2 ZAMBOANGA DEL SUR 97.7 108.4 111.9 151.8 127.4 147.1 108.9 126.0PAMPANGA 114.3 122.5 115.7 124.1 202.9 210.8 125.6 130.9

TARLAC 115.1 144.8 116.8 132.4 206.1 211.6 123.5 151.1 REGION X (NORTHERN MINDANAO)ZAMBALES 110.6 119.0 124.3 143.5 198.7 209.8 119.1 127.5 BUKIDNON 63.0 102.0 112.6 126.0 94.8 155.8 96.1 111.1

AURORA 108.3 127.4 101.7 114.9 136.2 181.6 117.5 134.7 CAMIGUIN 90.4 93.8 100.6 103.1 122.3 126.9 101.4 102.3NATIONAL CAPITAL REGION LANAO DEL NORTE 65.4 101.3 111.9 125.1 107.4 140.5 94.4 112.1

METRO MANILA 111.4 119.6 111.4 124.9 170.1 208.4 121.3 132.9 MISAMIS OCCIDENTAL 88.5 98.0 110.5 113.3 121.5 131.5 104.6 109.8REGION IV-A (CALABARZON) MISAMIS ORIENTAL 60.3 99.7 103.3 127.1 104.8 168.6 92.7 108.9

BATANGAS 110.9 119.9 114.9 136.8 125.6 164.3 117.5 128.4 REGION XI (DAVAO REGION)CAVITE 111.4 116.3 109.1 122.3 144.1 189.6 119.6 122.9

LAGUNA 105.9 116.0 104.2 115.5 126.3 156.8 112.3 120.6 DAVAO 96.4 105.6 113.1 123.6 106.3 134.3 104.8 114.9RIZAL 113.5 118.6 110.0 116.0 160.8 198.0 121.8 130.3 DAVAO DEL SUR 97.6 104.3 113.6 158.9 119.9 135.0 108.1 126.1

QUEZON 102.7 123.3 102.3 147.4 125.9 180.6 110.0 138.5 DAVAO ORIENTAL 97.6 108.4 119.6 136.6 112.1 132.1 111.6 118.8REGION IV-B (MIMAROPA) REGION XII (SOCCSKSARGEN)

MARINDUQUE 119.8 123.5 125.7 132.9 136.6 138.1 128.1 132.0 SOUTH COTABATO 103.5 112.2 129.9 154.0 118.5 146.7 121.1 125.4OCCIDENTAL MINDORO 118.7 185.0 129.3 146.5 143.5 180.3 127.9 171.4 COTABATO 98.8 114.9 108.1 127.7 121.9 163.3 108.0 120.4

ORIENTAL MINDORO 121.6 170.5 131.8 147.9 138.5 168.9 133.9 162.0 SARANGANI 101.6 109.8 141.2 164.4 118.6 142.7 121.5 128.5ROMBLON 118.4 134.9 133.6 135.9 127.1 141.0 126.1 137.9 SULTAN KUDARAT 103.8 114.9 121.1 140.8 130.1 157.1 119.0 126.4PALAWAN 107.6 126.0 147.8 178.0 130.8 169.4 127.9 147.3 REGION XIII- CARAGA

REGION V (BICOL) AGUSAN DEL NORTE 96.5 110.5 95.4 110.6 101.1 116.5 101.6 105.9ALBAY 118.7 126.7 110.0 154.1 131.9 156.1 121.1 144.4 AGUSAN DEL SUR 95.1 112.7 104.5 122.7 101.1 116.0 103.4 112.1

CAMARINES NORTE 115.6 122.4 112.8 149.4 131.3 147.9 123.3 140.0 SURIGAO DEL NORTE 108.3 111.9 87.6 99.8 102.1 112.5 99.2 105.7CAMARINES SUR 119.8 131.0 127.5 185.0 139.1 170.9 130.0 161.5 SURIGAO DEL SUR 108.8 114.5 100.6 124.6 101.4 112.3 104.5 113.2CATANDUANES 108.5 128.6 121.3 130.6 153.0 166.4 135.1 138.2 ARMM

MASBATE 118.6 123.7 105.7 148.6 111.6 143.7 112.1 138.3 BASILAN 104.9 106.2 149.5 156.8 138.7 141.9 126.2 129.0SORSOGON 119.0 120.8 104.2 123.6 117.6 134.4 113.8 126.5 MAGUINDANAO 107.1 116.2 111.8 126.5 140.1 162.6 116.7 123.6

LANAO DEL SUR 71.8 108.4 107.9 121.8 111.3 155.2 96.8 115.4SULU 111.2 114.3 166.2 171.4 142.6 149.1 135.5 140.4

Forecast Rainfall Analysis in Percent of Normal. (OCTOBER to DECEMBER 2010)Forecast Rainfall Analysis in Percent of Normal. (OCTOBER to DECEMBER 2010)

OCTOBER 2010 (%N)NOVEMBER 2010 (%N)DECEMBER 2010 (%N)O N D 2010 (%N) OCTOBER 2010 (%N)NOVEMBER 2010 (%N)DECEMBER 2010 (%N)O N D 2010 (%N)

Rainfall Forecast Range in % of Normal per Province (Oct – Dec 2010)

The period covers the first half of the NE monsoon season. Tracks of tropical cyclone during this period are likely across central and southern parts of Luzon, and Visayas with secondary tracks over Northern Mindanao.

Summary: La Niña is expected to bring more than average (above normal)

rainfall in most parts of the country during the OND season, based on the forecast.

Expected number of tropical cyclones (TCs) on the remaining months (Oct-Dec) are about 5-8. Average tracks during OND season - likely across Central and Southern Luzon and Visayas.

Summary: Precautionary measures should be done by all

concerned agencies against possible flooding, flashfloods and landslides in preparation for the expected La Niña to affect the country in the coming months.

***PAGASA will continue to monitor the development of the La Niña and the day-to-day associated rainfall/weather conditions that will affect the country. Updates will be issued as necessary.

http://www.pagasa.dost.gov.ph

THANK YOU…

“tracking the sky . . . helping the country”

IMPACTS OF ENSO ON PHILIPPINE RAINFALLIMPACTS OF ENSO ON PHILIPPINE RAINFALL

Legend:

Severe drought impacts

Drought impacts with major losses

Moderate drought impacts

Near normal to above normal condition

Way above normal condition

Potential for flood damage

Severe flood damage

RED colored years are EL NINO years, BLUE colored years are LA NINA years and BLACK colored years are NON_ENSO years

Historical El Niño and La Niña Episodes Based on the ONI computed using ERSST.v3b

Highest

El Niño ONI Value

Lowest

La Nina ONI ValueJAS 1951 - NDJ 1951/52 0.8 ASO 1949 – FMA 1951 -1.7

MAM 1957 – MJJ 1958 1.7 MAM 1954 – DJF 1956/57 -2.1

JJA 1963 – DJF 1963/64 1.0 ASO 1962 − DJF 1962/63 -0.8

MJJ 1965 – MAM 1966 1.6 MAM 1964 – DJF 1964/65 -1.1

OND 1968 – MJJ 1969 1.0 NDJ 1967/68 – MAM 1968 -0.9

ASO 1969 – DJF 1969/70 0.8 JJA 1970 – DJF 1971/72 -1.3

AMJ 1972 – FMA 1973 2.1 AMJ 1973 – MAM 1976 -2.0

ASO 1976 – JFM 1977 0.8 SON 1984 – ASO 1985 -1.0

ASO 1977 - DJF 1977/78 0.8 AMJ 1988 – AMJ 1989 -1.9

AMJ 1982 – MJJ 1983 2.3 ASO 1995 – FMA 1996 -0.7

JAS 1986 – JFM 1988 1.6 JJA 1998 – MJJ 2000 -1.6

AMJ 1991 – JJA 1992 1.8 SON 2000 – JFM 2001 -0.7

AMJ 1994 – FMA 1995 1.3 ASO 2007 – AMJ 2008 -1.4

AMJ 1997 – AMJ 1998 2.5

AMJ 2002 – FMA 2003 1.5

MJJ 2004 – JFM 2005 0.9

JAS 2006 - DJF 2006/07 1.1

MJJ 2009 – MAM 2010 1.8

NOTE:

After updating the ocean analysis to ERSST.v3b, a new La Niña episode was classified (ASO 1962- DJF 1962/63) and two previous La Niña episodes were combined into one single episode (AMJ 1973- MAM 1976).

PROVINCE PROVINCE

MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAXCORDILLERA ADMINISTRATIVE REGION (CAR) REGION VI (WESTERN VISAYAS)

ABRA 185.9 347.3 76.9 188.8 22.2 109.5 285.1 600.6 AKLAN 364.1 397.1 247.8 315.7 165.3 224.6 807.7 916.8BENGUET 427.8 561.2 119.3 196.6 28.6 119.7 596.6 846.2 ANTIQUE 305.7 391.9 220.8 272.3 111.7 184.7 638.3 841.0IFUGAO 430.8 503.9 189.2 340.5 108.8 287.0 748.6 1104.2 CAPIZ 330.5 377.3 257.9 339.7 163.1 251.0 775.1 967.9

KALINGA 380.2 583.1 296.4 619.2 207.5 633.7 884.1 1819.9 GUIMARAS 278.8 293.4 202.9 211.8 122.1 138.5 604.3 643.7APAYAO 222.8 319.5 160.9 351.7 86.2 201.1 471.3 864.6 ILOILO 300.5 352.8 211.4 291.1 114.0 235.0 638.3 851.8

MOUNTAIN PROVINCE 365.2 448.0 159.7 312.6 83.2 247.5 620.7 996.3 NEGROS OCCIDENTAL 223.9 289.2 187.1 235.9 119.5 184.7 533.5 702.8REGION I REGION VII (CENTRAL VISAYAS)

ILOCOS NORTE 137.6 265.1 34.2 240.4 0.0 97.9 167.3 603.5 BOHOL 163.5 230.7 153.3 178.5 126.6 161.9 470.5 542.5ILOCOS SUR 152.3 486.6 45.3 155.2 0.0 80.9 193.9 672.8 CEBU 179.1 256.1 166.2 232.6 119.0 248.2 476.5 715.8

LA UNION 387.5 489.8 99.5 132.3 0.6 28.6 489.7 650.7 NEGROS ORIENTAL 188.4 237.1 181.5 252.6 118.8 164.6 502.1 649.5PANGASINAN 229.1 470.4 22.4 156.8 0.0 127.9 193.0 734.1 SIQUIJOR 181.3 193.9 205.9 231.5 146.8 165.2 533.9 590.6

REGION II REGION VIII (EASTERN VISAYAS)BATANES 456.3 467.0 421.2 467.9 92.2 243.3 1027.1 1120.8 BILIRAN 261.0 285.3 279.2 307.8 330.1 364.8 870.2 957.9CAGAYAN 279.9 560.3 238.3 606.2 116.1 404.3 663.1 1529.8 EASTERN SAMAR 259.1 522.5 339.0 572.0 180.8 567.2 1001.7 1583.3ISABELA 380.2 583.1 296.4 619.2 207.5 633.7 884.1 1819.9 LEYTE 225.7 266.3 168.7 310.7 199.2 377.7 631.1 924.8

NUEVA VIZCAYA 461.5 527.2 165.8 366.0 102.9 364.2 767.6 1248.2 NORTHERN SAMAR 344.0 482.4 427.6 581.9 533.1 669.8 1304.7 1701.0QUIRINO 514.3 579.5 310.2 557.0 282.3 566.9 1108.8 1703.4SAMAR (WESTERN SAMAR)278.7 468.5 320.0 514.1 256.4 556.2 966.8 1463.1

REGION III (CENTRAL LUZON) SOUTHERN LEYTE 251.5 275.2 158.4 288.3 180.6 392.0 608.1 955.0BATAAN 292.3 376.0 56.4 73.5 22.3 71.9 406.7 478.6 REGION IX (ZAMBOANGA PENINSULA)

BULACAN 304.3 509.9 99.7 375.1 107.2 475.0 511.2 1359.9 ZAMBOANGA DEL NORTE 211.1 301.1 203.9 403.7 100.2 280.6 515.2 985.3NUEVA ECIJA 255.1 477.4 68.8 326.7 77.5 386.7 419.7 1169.4 ZAMBOANGA DEL SUR 200.2 286.7 186.1 365.7 86.4 244.5 473.8 895.9PAMPANGA 251.0 330.1 54.5 140.1 83.1 175.2 434.6 636.1

TARLAC 249.0 296.8 55.8 81.2 45.1 123.8 360.8 463.9 REGION X (NORTHERN MINDANAO)ZAMBALES 235.9 379.9 51.9 91.1 0.0 80.3 285.0 488.9 BUKIDNON 129.5 292.6 167.7 224.0 126.4 206.3 434.4 700.5

AURORA 451.5 616.5 293.2 656.1 300.9 702.3 1051.0 1974.8 CAMIGUIN 180.4 189.6 182.0 185.3 190.2 199.6 552.6 574.5NATIONAL CAPITAL REGION LANAO DEL NORTE 141.2 255.7 191.7 308.0 120.1 198.9 453.2 761.7

METRO MANILA 301.3 404.9 160.4 227.3 154.4 248.1 644.3 880.3 MISAMIS OCCIDENTAL 225.6 260.7 302.1 349.8 197.6 242.8 737.1 851.4REGION IV-A (CALABARZON) MISAMIS ORIENTAL 113.3 216.2 164.9 215.8 113.8 231.8 416.1 641.8

BATANGAS 280.0 427.1 108.4 420.6 49.7 374.4 438.1 1222.1 REGION XI (DAVAO REGION)CAVITE 254.2 301.3 92.8 183.5 38.5 154.3 414.3 638.8

LAGUNA 297.1 580.2 182.3 518.2 130.1 652.6 609.6 1751.0 DAVAO 154.8 264.5 151.0 331.9 128.2 363.5 447.4 945.0RIZAL 413.9 549.7 271.1 437.4 295.5 553.3 980.5 1540.4 DAVAO DEL SUR 95.0 231.8 134.4 189.5 92.0 158.3 325.0 571.6

QUEZON 407.5 727.6 358.1 702.5 330.4 990.8 1120.4 2392.3 DAVAO ORIENTAL 136.7 261.1 175.2 388.4 171.7 438.2 505.7 1087.7REGION IV-B (MIMAROPA) REGION XII (SOCCSKSARGEN)

MARINDUQUE 453.5 498.8 427.6 489.9 452.4 583.4 1333.5 1572.0 SOUTH COTABATO 106.8 182.6 127.0 172.9 76.2 101.0 313.8 450.9OCCIDENTAL MINDORO 308.1 491.5 95.3 290.1 8.7 241.5 412.0 957.3 COTABATO 178.0 256.8 159.2 230.9 103.8 148.5 441.9 636.0

ORIENTAL MINDORO 363.8 468.9 182.7 365.8 152.5 316.6 763.7 1099.9 SARANGANI 87.8 161.1 128.4 159.3 72.7 103.6 314.1 403.4ROMBLON 351.4 401.7 273.2 332.7 208.8 280.0 876.6 964.3 SULTAN KUDARAT 149.2 221.3 145.6 208.0 83.4 118.9 392.3 548.2PALAWAN 197.4 346.6 159.2 300.0 66.0 220.0 552.2 762.9 REGION XIII- CARAGA

REGION V (BICOL) AGUSAN DEL NORTE 206.8 258.7 194.1 338.5 203.2 440.8 610.0 1038.0ALBAY 366.3 433.5 464.9 557.5 456.6 744.0 1292.4 1704.5 AGUSAN DEL SUR 221.6 288.3 198.5 438.4 201.6 499.4 622.9 1226.0

CAMARINES NORTE 486.7 647.7 601.2 671.5 610.3 954.4 1698.2 2259.5 SURIGAO DEL NORTE 255.6 290.9 316.4 435.1 413.9 609.0 986.0 1331.3CAMARINES SUR 364.5 562.2 502.7 634.0 330.6 780.2 1221.9 1946.5 SURIGAO DEL SUR 254.5 297.9 332.3 481.7 389.3 557.9 981.0 1337.5CATANDUANES 449.4 497.7 574.0 686.9 690.3 986.6 1744.1 2130.7 ARMM

MASBATE 277.7 372.5 271.6 445.9 260.9 437.8 855.6 1206.9 BASILAN 176.6 190.6 167.2 179.7 63.3 79.6 407.1 449.9SORSOGON 345.9 414.3 418.6 529.1 551.3 725.7 1315.8 1669.2 MAGUINDANAO 186.8 245.8 167.5 220.7 105.7 140.2 459.9 606.8

LANAO DEL SUR 163.2 258.1 210.2 278.7 132.2 176.5 509.7 706.2SULU 151.1 161.9 188.3 212.0 88.9 110.5 435.8 483.1

Forecast Rainfall Analysis in mm.(OCTOBER to DECEMBER 2010)Forecast Rainfall Analysis in mm.(OCTOBER to DECEMBER 2010)

OCTOBER 2010 NOVEMBER 2010DECEMBER 2010 O N D 2010 OCTOBER 2010 NOVEMBER 2010DECEMBER 2010 O N D 2010

Rainfall Forecast Range in mm. per Province (Oct – Dec 2010)

Reanalysis of Vector Wind Composite Anomaly (Jun - Aug)

Source: ESRL (Earth System Research Laboratory)