Skip Navigation Linkweather.gov 
NOAA logo-Select to go to the NOAA homepage National Weather Service   NWS logo-Select to go to the NWS homepage
Central Pacific Hurricane Center

Local forecast by
"City, St" or Zip Code
  
   RSS FeedsRSS Feeds
Get Storm Info
   Products
   Satellite
   Radar
   Analyses/Forecasts
   Hydrology
   E-mail Updates
   Help with Advisories
Awareness
   Hurricane Safety
       Info

   Tropical Cyclone
      Names

   Saffir-Simpson
      Scale

   Glossary
   Acronyms
   FAQ
   Breakpoints
Hurricane History
   Annual Summaries
   Product Archive
   Climatology
About the CPHC
   Our Mission
   Our Office
   News Items
   Hawaii RSS FeedsHI RSS Feeds
Contact Us

Pacific Region Links
   Regional HQ
   WFO Honolulu
   WFO Guam
   WSO Pago Pago
   Pacific Tsunami
      Warning Center

   International
      Tsunami
      Information
      Center

   Pacific ENSO
      Application
      Center


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services
Follow the National Weather Service on Facebook
NWS on Facebook
Follow the National Weather Service on Twitter
NWS on Twitter
Weath
er-Ready Nation
Weather-Ready Nation

2009 Tropical Cyclones Central North Pacific

2009 Tropical Cyclones Central North Pacific



Tropical Cyclone Report
Tropical Storm Lana
(EP062009)
30 July - 2 August 2009

Thomas Birchard and Richard D. Knabb
Central Pacific Hurricane Center

Michael J. Brennan
National Hurricane Center

11 February 2010

Lana originated as a tropical depression in the extreme western portion of the east Pacific basin, and became a short-lived tropical storm in the central Pacific basin before moving well south of the Hawaiian Islands and dissipating.

a. Synoptic History

Lana had its origins in a tropical wave that entered the eastern Atlantic on 11 July and reached the eastern Pacific on 21 July. The area of disturbed weather associated with the wave merged with another area of disturbed weather on 26 July, and by 0000 UTC 27 July the system was located near 115-120°W. As the system moved westward, vertical wind shear remained unfavorable for development for a couple of days, but shear began to decrease on 29 July as a mid- to upper-level trough located north of the wave moved away. Deep convection began to increase late on 29 July and the system continued to become better organized early on 30 July. It is estimated that a tropical depression formed around 1200 UTC 30 July while centered about 1030 n mi east-southeast of Hilo, Hawaii. The "best track" chart of the tropical cyclone's path is given in Fig. 1, with the wind and pressure histories shown in Figs. 2 and 3, respectively. The best track positions and intensities are listed in Table 1[1].

The depression moved quickly westward at 16-17 kt to the south of the subtropical ridge, and the convective structure of the cyclone continued to become better organized. It crossed 140°W longitude and entered the central Pacific basin just prior to reaching tropical storm intensity around 1800 UTC 30 July, when it was centered about 935 n mi east-southeast of Hilo. Steady strengthening beneath upper-level anticyclonic flow continued for the next 24 h, and by 1800 UTC the next day Lana reached its peak intensity of 55 kt while located about 585 n mi southeast of Hilo. Increasing southwesterly vertical wind shear began to impinge upon the cyclone as it approached an upper-level trough over Hawaii, and Lana gradually weakened during the following two days as it continued westward in the low- to mid-level flow south of a ridge. By 1800 UTC 2 August, Lana had weakened to a tropical depression about 400 n mi south of Honolulu, Hawaii. Thereafter, only small, intermittent bursts of convection appeared in the northeastern quadrant, and the system degenerated to a remnant low six hours later. The low dissipated in the low-level trade wind flow shortly after 0600 UTC 3 August about 475 n mi southwest of Honolulu.

b. Meteorological Statistics

Observations in Lana (Figs. 2 and 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB), the Central Pacific Hurricane Center (PHFO), and the Satellite Analysis Branch (SAB). Data and imagery from NOAA polar-orbiting satellites, the NASA Tropical Rainfall Measuring Mission (TRMM), the NASA QuikSCAT, the European ASCAT onboard METOP-A, and Defense Meteorological Satellite Program (DMSP) satellites, among others, were also useful in constructing the best track of Lana.

Lana's estimated peak intensity of 55 kt on 31 July is based upon subjective Dvorak intensity estimates of 55 kt from both SAB and PHFO at 1800 UTC that day (Fig. 2).

No ship reports of winds of tropical storm force were reported in association with Lana.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Lana.

d. Forecast and Warning Critique

The genesis of Lana was not well anticipated. The precursor disturbance that developed into Lana was first mentioned in NHC's Tropical Weather Outlook issued at 1800 UTC 27 July, and was given a "low" probability of genesis (less than 30%) in the next 48 h. The genesis forecast remained in the low category through 1800 UTC 28 July. Due to increasing vertical wind shear, the disturbance was removed from the outlook at 0000 UTC 29 July. After the shear diminished later that day, the disturbance was again given a low probability of genesis. The probability of formation remained in the low category until genesis occurred.

NHC made only one forecast for Lana, which prevents any meaningful forecast critique. Official track forecast errors were 38, 75, 93, 86, and 85 n mi for the 12, 24, 36, 48, and 72 h forecasts, respectively. Official intensity forecast errors were 10 kt at 12 and 24 h, and 0 kt at 36, 48, and 72 h.

No coastal tropical cyclone watches or warnings were issued in association with Lana.

Table 1. Best track for Tropical Storm Lana, 30 July - 2 August 2009.

Date/Time
(UTC)
Latitude
(°N)
Longitude
(°W)
Pressure
(mb)
Wind Speed
(kt)
Stage
30 / 1200 12.0 139.1 1008 30 tropical depression
30 / 1800 12.1 140.6 1005 35 tropical storm
31 / 0000 12.6 142.3 1000 45 "
31 / 0600 13.0 143.9 997 50 "
31 / 1200 13.4 145.5 997 50 "
31 / 1800 13.8 146.9 995 55 "
01 / 0000 14.0 148.4 997 50 "
01 / 0600 14.2 149.8 999 45 "
01 / 1200 14.4 151.2 1000 45 "
01 / 1800 14.4 152.6 1000 45 "
02 / 0000 14.5 154.2 1002 40 "
02 / 0600 14.5 155.9 1003 40 "
02 / 1200 14.4 157.4 1004 35 "
02 / 1800 14.4 158.9 1006 30 tropical depression
03 / 0000 14.4 160.3 1008 25 low
03 / 0600 14.4 161.7 1010 20 "
03 / 1200         dissipated
31 / 1800 13.8 146.9 995 55 maximum wind speed and minimum pressure


Figure 1. Best track positions for Tropical Storm Lana, 30 July - 2 August 2009.


Figure 2. Selected wind observations and best track maximum sustained surface wind speed curve for Tropical Storm Lana,
30 July - 2 August 2009. Dashed vertical lines correspond to 0000 UTC.


Figure 3. Selected pressure observations and best track minimum central pressure curve for Tropical Storm Lana,
30 July - 2 August 2009. Dashed vertical lines correspond to 0000 UTC.

[1] A digital record of the complete best track, including wind radii, can be found on line at ftp://ftp.nhc.noaa.gov/atcf. Data for the current year's storms are located in the btk directory, while previous years' data are located in the archive directory.


Tropical Cyclone Report
Hurricane Felicia
(EP082009)
3-11 August 2009

Todd B. Kimberlain
National Hurricane Center

Derek Wroe and Richard D. Knabb
Central Pacific Hurricane Center

14 January 2010

Felicia strengthened into a major hurricane over the western portion of the eastern North Pacific basin. The hurricane gradually weakened over the central Pacific, and dissipated just east of the Hawaiian Islands.

a. Synoptic History

Felicia's genesis can be traced to a tropical wave that was first detected in satellite imagery over the tropical Atlantic on 23 July. The wave was barely identifiable for several days but became better defined as it approached the Lesser Antilles on 26 July. Little change in the wave was noted as it passed through the Caribbean Sea and moved across Central America during the last few days of July. Scattered deep convection began to develop in association with the wave after it moved into the eastern North Pacific on 29 July, but it was not until the wave passed 110°W on 1 August that deep convection increased further and showed signs of organization. Satellite images indicated several curved bands on 3 August around a developing circulation center, and the disturbance is estimated to have become a tropical depression by 1800 UTC 3 August. Additional organization occurred and the depression became a tropical storm around 0000 UTC 4 August, centered about 990 n mi southwest of the southern tip of Baja California. The "best track" chart of the tropical cyclone's path is given in Fig. 1, with the wind and pressure histories shown in Figs. 2 and 3, respectively. The best track positions and intensities are listed in Table 1[1].

Within an environment of low vertical wind shear and 28°-29°C sea surface temperatures, Felicia began a period of rapid intensification from the time it formed. A NASA Tropical Rainfall Measuring Mission (TRMM) 85-GHz microwave pass at 1327 UTC 4 August captured Felicia in the middle of this intensification phase, revealing a well-defined mid-level eye-like feature within a central dense overcast (Fig. 4). Microwave imagery and Dvorak satellite estimates suggest that Felicia continued to rapidly intensify and reached hurricane strength around 1800 UTC 4 August.

Felicia initially moved west-northwestward between 12 and 14 kt to the south of a well-defined deep-layer ridge covering the central portion of the eastern North Pacific. However, Felicia slowed to a forward speed of 9 to 10 kt and started moving on a more northwestward heading by 5 August, when it reached the western extent of a ridge to its north and encountered a trough digging along 130°W. The cyclone may have also been involved in a weak binary interaction with Tropical Storm Enrique to its northeast during its developing stage, with the separation distance between the two as little as 425 n mi around 1200 UTC 6 August. Despite their proximity, the tracks of the two cyclones indicate that whatever interaction occurred was minimal.

On a northwestward course, Felicia continued to rapidly intensify and reached its estimated peak intensity of 125 kt at 0600 UTC 6 August, while located about 1465 n mi east-southeast of Hilo, Hawaii. Although the environmental shear remained fairly light, gradual weakening began during the next 24 hours, followed by a faster weakening after Felicia began moving over 26° to 27°C sea surface temperatures. Around this time, mid-level ridging building to the north and west of the hurricane replaced the mid- to upper-tropospheric trough that was along 130°W. The change in steering features resulted in a more west-northwesterly course just prior to Felicia's entrance into the central North Pacific basin a hurricane with 80 kt winds around 1200 UTC 8 August.

Early on 9 August, aircraft reconnaissance data and microwave imagery indicated that the flight-level center was no longer collocated with the surface center. This marked the beginning of a weakening trend, as Felicia encountered increasing westerly vertical wind shear produced by a broad upper-level trough over and north of the Hawaiian islands. Felicia weakened to a tropical storm by 1200 UTC that day while centered about 550 n mi east of Hilo. By 0000 UTC 10 August, the shear had exacted a substantial toll on Felicia, as the low-level circulation center had become exposed from deep convection displaced to the northeast, and maximum winds had diminished to 45 kt, down from 75 kt just 24 hours earlier. As the tropical storm weakened, the dominant steering flow was a low- to mid-level subtropical ridge to the north, causing Felicia to assume a westward motion for the remainder of its existence.

Gradual weakening continued through 10 August in an environment of continued strong westerly shear. The upper-level trough responsible for the shear also created diffluence aloft, however, which helped to maintain an area of deep convection displaced to the north-northeast of the exposed low-level center. While this convection continued, aircraft reconnaissance and QuikSCAT data continued to indicate winds of tropical storm force to the north of the circulation center through early on 11 August. Later that day, the diffluent pattern aloft broke down, while vertical wind shear remained strong over the cyclone, and deep convection diminished. Felicia weakened to a tropical depression by 1200 UTC 11 August while centered 120 n mi northeast of Hilo, and became a remnant low around 1800 UTC. Shortly thereafter, the low-level circulation center became ill-defined as it interacted with the high terrain of the Big Island of Hawaii, and the circulation dissipated. Remnant moisture then continued westward over the rest of the Hawaiian Islands for the next couple of days.

b. Meteorological Statistics

Observations in Felicia (Figs. 2 and 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB) and the Satellite Analysis Branch (SAB), the Central Pacific Hurricane Center (CPHC), and the Joint Typhoon Warning Center (JTWC). Data and imagery from NOAA polar-orbiting satellites, including the Advanced Microwave Sounding Unit (AMSU) intensity estimates using the CIMSS technique, the NASA Tropical Rainfall Measuring Mission (TRMM), the NASA QuikSCAT, the NASA Aqua, the Department of Defense Windsat, and Defense Meteorological Satellite Program (DMSP) satellites, among others, were also useful in tracking Felicia and later constructing its best track.

Flight-level, dropsonde, and Stepped-Frequency Microwave Radiometer (SFMR) data were also obtained during five C-130J aircraft missions flown by the 53rd Weather Reconnaissance Squadron of the U.S. Air Force Reserve Command. The NOAA G-IV jet also flew three synoptic surveillance missions around Felicia during 7-9 August.

The estimated peak intensity of Felicia of 125 kt is based on several subjective Dvorak intensity estimates of 127 kt and a 3-hour Automated Dvorak Technique (ADT) mean of 6.5 (127 kt) at 0000 UTC 6 August. Several QuikSCAT passes were also helpful in estimating the tropical-storm-force wind radii of Felicia and its intensity as the cyclone approached Hawaii as a tropical storm.

No ship reports of tropical-storm-force winds or greater were received in association with Felicia.

While approaching the Hawaiian Islands from the east, Felicia generated large swells, resulting in surf heights of 6 to 10 ft that affected east-facing shores of the state during 10-12 August.

Although Felicia dissipated as a tropical cyclone before reaching the Hawaiian Islands, widespread heavy rainfall and some freshwater flooding occurred as the remnants of the system passed over the state during 11-13 August. A portion of Kamehameha Highway near Waikane on the island of Oahu was closed for several hours on 13 August, as Waikane Stream overflowed its banks and sent floodwaters over the road. The greatest rainfall totals associated with the remnants of Felicia were 14.63 in at Oahu Forecast National Wildlife Refuge on the island of Oahu, 13.46 in at Mount Waialeale on the island of Kauai, and 6.28 in at West Wailuaki on the island of Maui.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Felicia.

d. Forecast and Warning Critique

The genesis of Felicia was not well anticipated. The area of disturbed weather from which Felicia developed was introduced to the Tropical Weather Outlook about 30 h prior to the tropical cyclone's formation. The first several outlooks indicated slow development of the system but did not explicitly mention the possibility that a tropical depression could form until 18 hours before genesis occurred. The potential for genesis never reached the "high" category (> 50% in 48 h).

A verification of NHC official track forecasts is provided in Table 2b. Average official track errors for Felicia (with the number of cases in parentheses) were 22 (18), 38 (18), 51 (18), 63 (18), 75 (18), 91 (15), and 150 (11) n mi for the 12, 24, 36, 48, 72, 96, and 120 h forecasts, respectively. These errors are much lower than the long-term NHC average track errors, especially at 48 h and beyond. Interestingly, NHC forecasts exhibited skill above or rivaling the often difficult-to-beat variable consensus (TVCN) model through 72 h in Table 2b. Additionally, BAMD produced the lowest overall track errors for Felicia at all time ranges except 72 h. It is worth noting that OCD5 errors were also smaller than average, suggesting that the track of Felicia was easier to forecast than average. This may also help explain the small OFCL errors.

A verification of NHC official intensity forecasts are shown in Table 3b. The average official intensity errors were 8 (18), 14 (18), 18 (18), 19 (18), 12 (18), 9 (15) and 10 (11) kt for the 12, 24, 36, 48, 72, 96, and 120 h forecasts, respectively. For comparison, the average long-term official intensity errors are 6, 10, 13, 15, 18, 19, and 19 kt, respectively. NHC forecast intensity errors were higher than the long-term average intensity errors through 48 h, revealing the inability of early forecasts to capture Felicia's period of rapid intensification starting at the time of genesis. It should be noted that none of the intensity guidance models for Felicia performed well through the 48 h time range. The large OCD5 errors at these time ranges indicate increased difficulty associated with these forecasts. Interestingly, NHC forecast intensity errors were substantially lower than the long-term average at 72 h and beyond, likely because they did not involve forecasting the initial rapid intensification phase.

Table 4 summarizes the tropical storm watches issued by the CPHC in association with Felicia.

Watches associated with Felicia are given in Table 4. A tropical storm watch was issued at 0300 UTC 9 August for the islands of Hawaii, Maui, Molokai, Lanai, and Kahoolawe and was expanded to cover the island of Oahu at 0300 UTC 10 August. Felicia dissipated before reaching the Hawaiian Islands, and no warnings were issued.

Table 1. Best track for Hurricane Felicia, 3-11 August 2009.

Date/Time
(UTC)
Latitude
(°N)
Longitude
(°W)
Pressure
(mb)
Wind Speed
(kt)
Stage
03 / 1800 11.0 121.1 1007 25 tropical depression
04 / 0000 11.5 122.4 1004 35 tropical storm
04 / 0600 11.8 123.7 1000 45 "
04 / 1200 12.0 124.9 994 55 "
04 / 1800 12.2 126.1 987 65 hurricane
05 / 0000 12.6 126.9 980 75 "
05 / 0600 13.2 127.6 972 85 "
05 / 1200 13.7 128.5 960 100 "
05 / 1800 14.2 129.3 948 115 "
06 / 0000 14.7 130.1 935 125 "
06 / 0600 15.1 130.8 935 125 "
06 / 1200 15.7 131.5 940 120 "
06 / 1800 16.2 132.3 944 115 "
07 / 0000 16.7 133.2 948 115 "
07 / 0600 17.3 134.0 955 105 "
07 / 1200 17.7 135.2 960 100 "
07 / 1800 18.1 136.3 965 95 "
08 / 0000 18.6 137.4 970 90 "
08 / 0600 18.9 138.7 973 85 "
08 / 1200 19.2 140.1 976 80 "
08 / 1800 19.6 141.4 981 75 "
09 / 0000 19.9 142.7 982 75 "
09 / 0600 20.2 144.0 984 70 "
09 / 1200 20.5 145.3 994 60 tropical storm
09 / 1800 20.9 146.5 1001 50 "
10 / 0000 21.0 147.7 1002 45 "
10 / 0600 21.0 148.7 1003 45 "
10 / 1200 20.9 149.6 1005 40 "
10 / 1800 20.9 150.6 1007 40 "
11 / 0000 20.9 151.6 1008 35 "
11 / 0600 20.9 152.5 1009 35 "
11 / 1200 20.8 153.3 1010 30 tropical depression
11 / 1800 20.7 154.2 1010 30 low
12 / 0000         dissipated
  06 / 0000   14.7   130.1   935   125 minimum pressure/maximum wind

Table 2a. NHC official (OFCL) and climatology-persistence skill baseline (OCD5) track forecast errors (n mi) for Hurricane Felicia. Mean errors for the five-year period 2004-8 are shown for comparison. Official errors that are smaller than the five-year means are shown in boldface type. * CPHC statistics are incomplete at this time, and will be provided as soon as possible.

Forecast Period (h)
12 24 36 48 72 96 120
OFCL (Felicia) 21.6 38.2 51.2 63.1 75.0 90.5 150.4
OCD5 (Felicia) 26.2 47.0 75.1 106.6 170.4 213.9 207.7
Forecasts 18 18 18 18 18 15 11
OFCL (2004-8) 31.0 51.7 71.7 90.2 123.6 161.3 201.8
OCD5 (2004-8) 38.4 73.6 111.9 149.1 214.2 261.1 311.5

Table 2b. Homogeneous comparison of selected track forecast guidance models (in n mi) for Hurricane Felicia east of 140°W. Errors smaller than the NHC official forecast are shown in boldface type. The number of official forecasts shown here will generally be smaller than that shown in Table 2a due to the homogeneity requirement.

Model ID Forecast Period (h)
12 24 36 48 72 96 120
OFCL 18.9 36.3 49.1 60.9 71.8 89.8 149.5
OCD5 24.6 48.4 76.8 111.2 173.3 214.4 213.9
GFSI 25.8 41.9 51.8 61.0 72.2 120.6 178.8
GHMI 19.5 39.4 57.5 73.1 106.2 129.4 197.2
HWFI 26.1 48.9 62.9 78.8 113.5 150.0 200.8
NGPI 38.7 73.9 96.3 107.5 104.5 132.5 181.5
EMXI 22.3 44.4 62.2 79.4 97.2 93.3 122.4
TVCN 20.9 39.8 54.7 64.2 76.4 85.4 127.4
TVCC 21.1 44.3 57.3 77.3 92.3 122.7 174.5
BAMS 25.0 53.2 79.2 105.4 129.4 163.7 178.4
BAMM 20.9 38.3 56.7 83.9 140.7 165.0 147.0
BAMD 16.2 29.5 45.2 59.4 82.2 85.6 90.5
LBAR 24.2 39.1 47.4 53.2 78.7 107.4 147.3
Forecasts 14 14 14 14 14 12 9

Table 3a. NHC official (OFCL) and climatology-persistence skill baseline (OCD5) intensity forecast errors (kt) for Hurricane Felicia east of 140°W. Mean errors for the five-year period 2004-8 are shown for comparison. Official errors that are smaller than the five-year means are shown in boldface type.

Forecast Period (h)
12 24 36 48 72 96 120
OFCL (Felicia) 8.3 13.9 18.1 18.9 11.7 9.3 10.0
OCD5 (Felicia) 10.4 15.1 19.6 18.7 9.1 10.5 13.5
Forecasts 18 18 18 18 18 15 11
OFCL (2004-8) 6.2 10.2 13.3 15.1 17.7 19.0 18.8
OCD5 (2004-8) 7.1 11.5 14.7 16.8 18.9 20.3 20.2

Table 3b. Homogeneous comparison of selected intensity forecast guidance models (in kt) for Hurricane Felicia. Errors smaller than the NHC official forecast are shown in boldface type. The number of official forecasts shown here will generally be smaller than that shown in Table 3a due to the homogeneity requirement.

Model ID Forecast Period (h)
12 24 36 48 72 96 120
OFCL 8.3 13.9 18.1 18.9 11.7 9.6 11.7
OCD5 10.4 15.1 19.6 18.7 9.1 10.7 12.6
HWFI 12.2 17.1 20.3 20.4 14.0 10.9 15.3
GHMI 13.4 24.9 33.9 30.4 19.7 14.0 14.8
DSHP 10.1 14.3 18.2 17.5 13.2 11.9 11.3
LGEM 10.7 18.3 23.7 24.6 18.4 13.9 10.1
ICON 11.0 18.1 23.4 22.7 15.8 11.1 9.8
IVCN 11.3 18.2 23.2 22.2 14.4 9.6 10.4
Forecasts 18 18 18 18 18 14 9

Table 4. Watch summary for Hurricane Felicia, 9 - 11 August 2009.

Date/Time (UTC) Action Location
09 / 0300 Tropical Storm Watch issued Islands of Hawaii, Maui, Molokai, Lanai, and Kahoolawe
10 / 0300 Tropical Storm Watch issued Island of Oahu
10 / 2100 Tropical Storm Watch discontinued Island of Hawaii
11 / 2100 Tropical Storm Watch discontinued All


Figure 1. Best track positions for Hurricane Felicia, 3-11 August 2009.


Figure 2. Selected wind observations and best track maximum sustained surface wind speed curve for Hurricane Felicia, 3 - 11 August 2009. Dashed vertical lines correspond to 0000 UTC.


Figure 3. Selected pressure observations and best track minimum central pressure curve for Hurricane Felicia, 3 - 11 August 2009. Dashed vertical lines correspond to 0000 UTC.


Figure 4. An 85 GHz channel pass over Felicia from a NASA Tropical Rainfall Measuring Mission (TRMM) microwave pass at 1327 UTC 4 August. Image provided by the Naval Research Laboratory's Marine Meteorology Division in Monterey, CA.

[1] A digital record of the complete best track, including wind radii, can be found on line at ftp://ftp.nhc.noaa.gov/atcf. Data for the current year's storms are located in the btk directory, while previous year's data are located in the archive directory.


Tropical Cyclone Report
Tropical Storm Maka
(CP012009)
11-18 August 2009

Timothy A. Craig
Central Pacific Hurricane Center

15 November 2009

a. Overview

Tropical Depression One-C (TD-1C) developed near 13.5°N 170.0°W, or about 790 nm southwest of Lihue, Hawaii at 0000 UTC 11 August. The west-northwestward moving disturbance from which TD-1C formed was first identified at 1800 UTC 08 August near 10.0°N 159.0°W, or about 725 nm south of Lihue, Hawaii.

TD-1C intensified to a tropical storm at 1200 UTC 11 August, and the Central Pacific Hurricane Center (CPHC) named the system Maka ("Eye" in English). Maka stayed on a west-northwest course attaining peak intensity with maximum sustained winds of 45 knots at 1200 UTC 11 August. Maka weakened to a tropical depression at 0000 UTC 12 August, and remained a tropical depression until the CPHC stopped issuing advisories at 1800 UTC 12 August.

The resultant remnant low moved west, crossing 180°W near 14.3°N shortly after 0600 UTC 13 August. The low turned to the northwest and north over the next several days, reaching 15.3°N 173.1°E at 1800 UTC 15 August. The Joint Typhoon Warning Center (JTWC) upgraded Maka to a tropical storm at that time, and proceeded to downgrade the system to a tropical depression at 0600 UTC 17 August. The last advisory issued by JTWC on Maka was at 0600 UTC 18 August.

b. Synoptic History

Sea surface temperatures were around 28 Deg C and vertical wind shear was insignificant near Maka until 12 August. At low levels, a 1026 hPa subtropical high was centered near 40°N 171°W and an associated subtropical ridge extended from the high north of Maka to near 27°N 163°E. This placed Maka well within a deep layered easterly flow. With the friendly environment, Maka intensified whilst staying on a west-northwest course east of 180°W.

On 12 August, Maka encountered an area of southwesterly shear located south of a middle- and upper-level low pressure system centered near 15.1°N 172.7°W. The shear over a 12 hour period weakened and disorganized Maka resulting in the downgrade to a tropical depression and the cessation of advisories by CPHC. Once west of 180°W, a mid-latitude trough eroded the west end of the subtropical ridge northwest of Maka. The cyclone subsequently turned to the northwest and north toward the weakness in the pressure field.


Figure 1. This infrared satellite image of Maka was taken when the tropical cyclone was at its peak intensity. For reference, the island of Kauai is located in the upper right hand corner of the image.

c. Casualty and Damage Statistics

Maka was never over or near land. Therefore, no tropical cyclone watches or warnings were issued. There were no weather-related casualties or damage reported.

d. Forecast Critique

The genesis of Maka was not well anticipated. The precursor disturbance that developed into Maka was first mentioned in CPHC's Tropical Weather Outlook (TWO) issued at 1800 UTC 08 August. This TWO, as well as succeeding TWOs through 1800 UTC 10 August, only stated that "slow development is possible over the next two days."

GOES and microwave satellite imagery showed that throughout its life span Maka regularly oscillated between being organized and disorganized. Subsequently, the fix data provided by various agencies often had a large spread. This made it difficult to determine an initial position and intensity. In fact, on at least two occasions, the CPHC forecaster was unsure if Maka was a closed circulation at lower levels or a sharp surface trough. Confidence in the official position and intensity as well as the forecast was therefore quite low.

Table 1. Best Track Data for Tropical Storm Maka 11-18 August 2009

Date/Time
(UTC)
Latitude
(°N)
Longitude
(°W)
Pressure
(mb)
Wind Speed
(kt)
Stage/Notes
08/1800 10.0 159.0 1009 25 Disturbance
09/0000 10.7 160.2 1012 15 "
09/0600 11.2 161.4 1011 20 "
09/1200 11.7 162.5 1011 20 "
09/1800 12.0 163.7 1011 20 "
10/0000 12.3 165.0 1011 20 "
10/0600 12.5 166.3 1011 20 "
10/1200 12.8 167.6 1010 20 "
10/1800 13.1 168.8 1009 25 "
11/0000 13.4 169.7 1009 30 Tropical Depression
11/0600 13.7 170.7 1009 30 "
11/1200 13.9 171.3 1008 35 Tropical Storm
11/1800 14.1 171.8 1008 35 "
12/0000 14.3 172.4 1008 30 Tropical Depression
12/0600 14.4 173.8 1008 30 "
12/1200 14.2 175.3 1008 30 "
12/1800 14.3 176.8 1009 25 "
13/0000 14.4 178.3 1011 25 Disturbance
13/0600 14.3 179.7 1011 25 "
14/0000 13.8 178.6E 1010 20 "
14/0600 13.1 177.3E 1009 20 "
14/1200 13.3 175.9E 1007 20 "
14/1800 13.5 174.6E 1003 25 Tropical Depression
15/0000 13.7 174.0E 1003 25 "
15/0600 14.4 173.2E 1002 30 "
15/1200 14.9 173.1E 1001 30 "
15/1800 15.3 173.1E 997 35 Tropical Storm
16/0000 15.8 173.2E 992 45 "
16/0600 16.0 173.2E 992 45 "
16/1200 16.1 173.2E 992 40 "
16/1800 16.3 173.1E 994 35 "
17/0000 16.3 172.8E 995 35 "
17/0600 16.2 172.6E 998 30 Tropical Depression
17/1200 16.1 172.3E 1000 30 "
17/1800 16.1 172.0E 1000 30 "
18/0000 16.0 171.6E 1000 25 "
18/0600 15.9 171.1E 1006 25 "

Table 2. Track Verification Table entries are track forecast errors, measured in nautical miles. Values in parentheses indicate the number of forecasts. Values in bold represent guidance forecast errors equal to or less than the office CPHC forecast.

Forecast 12-hr 24-hr 36-hr 48-hr 72-hr 96-hr 120-hr
CPHC 70 (6) 103 (5) 125 (4) 170 (2) 373 (4) 376 (7) 439 (7)
CLP5 81 (6) 132 (6) 132 (4) 207 (3) 282 (5) 173 (8) 253 (8)
BAMD 53 (6) 103 (6) 133 (4) 259 (3) 406 (5) 438 (8) 530 (8)
BAMM 56 (6) 90 (6) 118 (4) 205 (3) 330 (5) 346 (8) 391 (8)
BAMS 64 (6) 99 (6) 82 (4) 154 (3) 226 (5) 216 (8) 255 (8)
GFDL 64 (6) 86 (5) 84 (4) 189 (2) 393 (4) 488 (7) 567 (7)
AVNO 76 (19) 117 (16) 171 (14) 266 (10) 386 (8) 423 (8) 482 (7)
NOGAPS 70 (17) 119 (14) 178 (11) 237 (8) 369 (6) 418 (6) 606 (6)
GUNA 77 (3) 149 (3) 160 (2) 263 (2) 375 (5) 391 (5) 504 (5)

Additional information on Maka is located at the CPHC website.


Tropical Cyclone Report
Hurricane Guillermo
(EP102009)
12-19 August 2009

Eric S. Blake
National Hurricane Center

Sam Houston and Richard D. Knabb
Central Pacific Hurricane Center

10 February 2010

Guillermo became a Category 3 hurricane over the open waters of the eastern Pacific Ocean and did not affect land. It persisted as a tropical storm, however, at a relatively high latitude over the central Pacific basin for an unusual amount of time.

a. Synoptic History

Guillermo was spawned by a large, high-amplitude tropical wave that left the west coast of Africa on 26 July. The wave moved westward without significant organization, entering the eastern Pacific on 5 August. Convection increased along the wave axis on 8 August, and an elongated low formed the next day with disorganized banding features noted. Thunderstorms increased markedly near the circulation center late on 11 August, leading to a better-defined circulation by early on 12 August. It is estimated that a tropical depression formed by 1200 UTC 12 August, located about 570 n mi south-southwest of the southern tip of Baja California, and the depression became a tropical storm 12 h later. The "best track" chart of the tropical cyclone's path is given in Figure 1, and the best track positions and intensities are listed in Table 1[1].

Soon after genesis, Guillermo began to intensify, strengthening from a weak tropical storm into a major hurricane in about 48 hours while moving to the west and west-northwest. A banded eye was noted in visible satellite images late on 13 August, and Guillermo became a hurricane early the next day. However, further strengthening was briefly arrested as the banding eye structure transitioned into a central dense overcast pattern, a change which occasionally precedes rapid intensification. Warm water, light shear, and an expanding outflow pattern aloft also probably contributed to a rapid intensification of Guillermo late on 14 August. It became a major hurricane on 15 August, reaching a peak intensity of 110 kt at 1200 UTC while located about 1300 n mi west-southwest of the southern tip of Baja California.

A weakening trend began later that day as sea surface temperatures decreased, and by the time Guillermo crossed into the central Pacific basin very late on 16 August, the cyclone had weakened to an intensity of 65 kt. A gradual decline in intensity continued during the next three days over relatively cool sea-surface temperatures and within an environment of moderate westerly wind shear associated with the flow around a mid- to upper-level trough located to the west of the tropical cyclone. Guillermo headed generally northwestward, well to the north of Hawaii during this period, around a subtropical ridge located to its northeast. By 0600 UTC 17 August, Guillermo weakened to a tropical storm while centered about 740 n mi east of Hilo, Hawaii. Deep convection disappeared near the circulation center later that day, although a QuikSCAT pass over the cyclone at 1648 UTC 17 August revealed winds up to 45 kt within convection far north of the exposed center. By 1800 UTC 19 August, the convection well removed from the center had also vanished, and Guillermo degenerated to a remnant low centered about 550 n mi north of Hawaii.

As the low continued northwestward at about 12 kt, it encountered a frontal zone and developed extratropical characteristics. Deep convection reformed in the northeastern semicircle and, based upon QuikSCAT data, it is estimated that maximum winds increased to 40 kt at 1200 UTC 20 August while the extratropical cyclone was centered about 700 n mi north of Hawaii. The cyclone turned northward as it was steered around the western periphery of the subtropical ridge to its east. Thunderstorms continued in association with the low until around 0600 UTC 21 August, but the system weakened and turned northeastward. Once again reduced to a swirl of low clouds, the low became elongated and was eventually absorbed by an approaching cold front around 1200 UTC 23 August.

b. Meteorological Statistics

Observations in Guillermo (Figs. 2 and 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB), the Satellite Analysis Branch (SAB), the Central Pacific Hurricane Center, UW-CIMSS intensity estimates using the Advanced Dvorak Technique (ADT) and the Advanced Microwave Sounding Unit (AMSU). Data and imagery from NOAA polar-orbiting satellites, Defense Meteorological Satellite Program (DMSP) satellites, National Aeronautics and Space Administration (NASA) satellites, including TRMM, QuikSCAT, and Aqua, the U.S. Navy WindSat, and the EUMETSAT ASCAT, among other satellites, were also useful in constructing the best track of Guillermo.

The 110-kt peak intensity of Guillermo is based on a blend of satellite estimates from TAFB, SAB, and the ADT technique from UW-CIMSS. Several QuikSCAT passes were helpful for estimating the intensity of Guillermo as it persisted as a tropical storm well north of Hawaii.

There were two ships reporting winds of tropical storm force associated with Guillermo. A ship with the call letters WDC378 measured 38 kt sustained winds on 18 August at 0000 UTC, and 17 h later the ship "Maui" reported 37 kt winds.

c. Forecast and Warning Critique

The genesis of Guillermo was well anticipated. The wave that eventually became Guillermo was introduced in the Tropical Weather Outlook (TWO) about three days before genesis. The genesis forecasts reached the medium (between 30-50%) category about 42 h before formation, although the chance of formation only reached the high (>50% percent) category six hours before genesis.

A verification of NHC official track forecasts for Guillermo is given in Table 2a. Official forecast track errors were considerably lower than the mean official errors for the previous five-year period at all forecast periods except for 120 h. The higher errors at 120 h were due to the storm turning more to the northwest over the central Pacific when a more westward track was anticipated. A homogeneous comparison of the official track errors with selected guidance models is given in Table 2b. The official forecast was better than or competitive with all guidance through 48 h, with the GFS-based guidance (GFS, HWRF, GFDL) superior in the longer time periods.

A verification of NHC official intensity forecasts for Guillermo is given in Table 3a. Official forecast intensity errors were much higher than the mean official errors for the previous five-year period through 72 h and then below the long-term mean afterwards. The rapid strengthening of Guillermo was not well forecast by NHC and caused the large errors. A homogeneous comparison of the official track errors with selected guidance models is given in Table 3b. Although the model errors were also large, the stati