Number range CHAPTERTropical Cyclone Report

Tropical Storm Julio

(EP112008)

23-26 August 2008

Richard J. Pasch

National Hurricane Center

10 February 2009

Julio made landfall in the southern Baja California peninsula as a weak
tropical storm.

a.  Synoptic History

    The tropical wave that moved off the west coast of Africa on 6
    August and spawned Atlantic Tropical Storm Fay on 15 August near
    Puerto Rico also appears to have produced Julio. The wave crossed
    southern Central America and moved over the eastern North Pacific
    Ocean on 17 August. There was not much organized deep convection
    associated with the wave as it proceeded westward to the south of
    Central America and Mexico over the next several days. By 21 August,
    there was an increase in showers and thunderstorms associated with
    the system while it was located a couple hundred n mi to the south
    of Acapulco, Mexico. A broad surface low pressure system soon formed
    in this region, but development was hindered by strong easterly
    vertical wind shear. By 1200 UTC 23 August, however, deep convection
    became persistent enough near the center of the low to warrant its
    designation as a tropical depression centered about 315 n mi
    south-southeast of the southern tip of Baja California (Cabo San
    Lucas). 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].

    About six hours after formation, the depression strengthened
    slightly and became a tropical storm. Julio moved
    north-northwestward along the periphery of a mid-tropospheric high
    pressure area over west-central Mexico. Although east-northeasterly
    shear continued to inhibit intensification, the storm strengthened a
    little more, and it reached its peak intensity of 45 kt around 1200
    to 1800 UTC 24 August, during which time the center passed near and
    just west of Cabo San Lucas. Julio then made landfall in southern
    Baja California, about 35 n mi west-southwest of La Paz around 0000
    UTC 25 August, with an estimated intensity of 40 kt. The system
    continued to move north-northwestward along the Baja peninsula that
    day while slowly weakening. Julio turned northward and its center
    reached the Gulf of California in the vicinity of Santa Rosalia just
    before 0000 UTC 26 August, by which time the cyclone had weakened to
    a tropical depression. Julio slowed and turned eastward over the
    central Gulf of California while gradually weakening, and
    degenerated into a remnant low by 1800 UTC 26 August. The low
    drifted eastward, and it dissipated near Tastiota, on the coast of
    mainland Mexico, by 1200 UTC 27 August.

b.  Meteorological Statistics

    Observations in Julio (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) as
    well as ship reports. Data and imagery from NOAA polar-orbiting
    satellites, the NASA Tropical Rainfall Measuring Mission (TRMM), the
    NASA QuikSCAT, and Defense Meteorological Satellite Program (DMSP)
    satellites, among others, were also useful in tracking Julio.

    Ship reports of tropical storm-force winds associated with Julio are
    given in Table 2. An automated station at Cabo San Lucas, operated
    by the Meteorological Service of Mexico, reported a 10-min average
    wind of 38 kt with a gust to 51 kt around 1600 UTC 24 August. This
    wind sensor is at an elevation of about 735 feet above sea level.
    Twenty-four hour rainfall totals of 6.54 in and 5.20 in were
    reported in southern Baja California at Loreto on 24 August and at
    Mulege on 25 August, respectively.

c.  Casualty and Damage Statistics

    Julio caused one death, a drowning near Mulege in Baja California.
    Julio produced some flooding over the Baja California peninsula,
    although damage estimates for Mexico are not available.

d.  Forecast and Warning Critique

    The tropical wave and associated area of disturbed weather that
    formed into Julio were first mentioned in the Tropical Weather
    Outlook (TWO) 42 h before the time of the tropical cyclone's
    genesis, and the genesis probabilities went from the "low" to the
    "medium" category 36 h before formation. However the potential for
    the system to become a tropical depression was not stated in the TWO
    until 18 h prior to genesis, and the probability was only set to
    "high" right at the time of genesis.

    A verification of official and guidance model track forecasts is
    given in Table 3. Average official track errors for Julio were 31,
    59, 90, 116, and 159 n mi for the 12, 24, 36, 48, and 72 h
    forecasts, respectively. The number of forecasts ranged from 11 at
    12 h to just one at 72 h. These errors are somewhat greater than the
    average 5-yr official track errors for the 24 through 72 h forecast
    intervals (Table 4), albeit for a very small sample of forecasts.

    A verification of official and guidance model intensity forecasts is
    given in Table 4. Average official intensity errors were 3, 4, 4, 4,
    and 10 kt for the 12, 24, 36, 48, and 72 h forecasts, respectively.
    For comparison, the average 5-yr official intensity errors are 6,
    10, 14, 16, and 19 kt, respectively.

Watches and warnings associated with Julio are given in Table 5. A
tropical storm warning was issued for a portion of southern Baja
California about 21 h prior to landfall in that area. However it is
likely that Julio's radius of maximum winds, and tropical storm-force
winds, were onshore in the warning area within 15 h of the issuance of
the warning.

Number range CHAPTERTable 1. Best track for Tropical Storm Julio, 23-26
August 2008.

+-----------+---------+---------+---------+---------+----------------+
| Date/Time | L       | Lo      | P       | Wind    | Stage          |
|           | atitude | ngitude | ressure | Speed   |                |
| (UTC)     |         |         |         |         |                |
|           | (°N)    | (°W)    | (mb)    | (kt)    |                |
+-----------+---------+---------+---------+---------+----------------+
| 23 / 1200 | 18.2    | 107.5   | 1007    | 30      | tropical       |
|           |         |         |         |         | depression     |
+-----------+---------+---------+---------+---------+----------------+
| 23 / 1800 | 19.1    | 108.1   | 1005    | 35      | tropical storm |
+-----------+---------+---------+---------+---------+----------------+
| 24 / 0000 | 20.0    | 108.6   | 1002    | 40      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 24 / 0600 | 20.9    | 109.2   | 1001    | 40      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 24 / 1200 | 21.9    | 109.8   | 1000    | 45      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 24 / 1800 | 22.9    | 110.2   | 998     | 45      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 25 / 0000 | 23.9    | 110.9   | 999     | 40      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 25 / 0600 | 25.2    | 111.5   | 1001    | 35      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 25 / 1200 | 26.3    | 112.0   | 1001    | 35      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 25 / 1800 | 27.1    | 112.3   | 1001    | 35      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 26 / 0000 | 27.6    | 112.4   | 1001    | 30      | tropical       |
|           |         |         |         |         | depression     |
+-----------+---------+---------+---------+---------+----------------+
| 26 / 0600 | 28.0    | 112.4   | 1003    | 30      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 26 / 1200 | 28.2    | 112.2   | 1005    | 25      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 26 / 1800 | 28.3    | 112.1   | 1005    | 25      | low            |
+-----------+---------+---------+---------+---------+----------------+
| 27 / 0000 | 28.3    | 111.9   | 1005    | 25      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 27 / 0600 | 28.3    | 111.6   | 1007    | 20      | \"             |
+-----------+---------+---------+---------+---------+----------------+
| 27 / 1200 |         |         |         |         | dissipated     |
+-----------+---------+---------+---------+---------+----------------+
| 24 / 1800 | 22.9    | 110.2   | 998     | 45      | minimum        |
|           |         |         |         |         | pressure       |
+-----------+---------+---------+---------+---------+----------------+
| 25 / 0000 | 23.9    | 110.9   | 999     | 40      | landfall on    |
|           |         |         |         |         | the west coast |
|           |         |         |         |         | of southern    |
|           |         |         |         |         | Baja           |
|           |         |         |         |         | California     |
|           |         |         |         |         | about 35 n mi  |
|           |         |         |         |         | west-southwest |
|           |         |         |         |         | of La Paz      |
+-----------+---------+---------+---------+---------+----------------+

Number range CHAPTERTable 2. Selected ship reports with winds of at
least 34 kt for Tropical Storm Julio, 23-26 August 2008.

+-----------+-----------+-----------+-----------+-----------+-----------+
| Date/Time | Ship call | Latitude  | Longitude | Wind      | Pressure  |
| (UTC)     | sign      |           |           |           |           |
|           |           | (°N)      | (°W)      | dir/speed | (mb)      |
|           |           |           |           | (kt)      |           |
+-----------+-----------+-----------+-----------+-----------+-----------+
| 23 / 2000 | DDFD2     | 19.2      | 108.5     | 350 / 40  | 1004.0    |
+-----------+-----------+-----------+-----------+-----------+-----------+
| 24 / 0000 | DHER      | 20.7      | 107.9     | 130 / 35  | 1004.5    |
+-----------+-----------+-----------+-----------+-----------+-----------+
| 24 / 0100 | DDFD2     | 19.7      | 110.1     | 330 / 35  | 1006.0    |
+-----------+-----------+-----------+-----------+-----------+-----------+

Number range CHAPTERNumber range CHAPTERTable 3. Track forecast
evaluation (heterogeneous sample) for Tropical Storm Julio, 23-26 August
2008. Forecast errors (n mi) are followed by the number of forecasts in
parentheses. Errors smaller than the NHC official forecast are shown in
boldface type.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Number    | For   |       |       |       |       |       |       |
| range     | ecast |       |       |       |       |       |       |
| CHAPTE    | P     |       |       |       |       |       |       |
| RForecast | eriod |       |       |       |       |       |       |
| Technique | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CLP5      | 37    | 85 (  | 117 ( | 170 ( | 346 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFNI      | 51 (  | 90 (  | 101 ( | **    |       |       |       |
|           | 8)    | 6)    | 4)    | 115** |       |       |       |
|           |       |       |       | ( 2)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDI      | 36    | *     | *     | *     | **    |       |       |
|           | (11)  | *57** | *74** | *90** | 138** |       |       |
|           |       | ( 9)  | ( 7)  | ( 5)  | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| HWFI      | 34    | *     | *     | **    | *     |       |       |
|           | (11)  | *46** | *78** | 110** | *88** |       |       |
|           |       | ( 9)  | ( 7)  | ( 5)  | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSI      | 35    | 68 (  | 109 ( | 171 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| AEMI      | 43    | 84 (  | 127 ( | *     |       |       |       |
|           | (11)  | 8)    | 6)    | *84** |       |       |       |
|           |       |       |       | ( 2)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPI      | 63    | 114 ( | 183 ( | 216 ( |       |       |       |
|           | (10)  | 7)    | 5)    | 2)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKMI      | 38    | 59 (  | *     | 117 ( |       |       |       |
|           | (10)  | 8)    | *81** | 4)    |       |       |       |
|           |       |       | ( 6)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| EGRI      | 33    | *     | *     | **    |       |       |       |
|           | (10)  | *53** | *79** | 110** |       |       |       |
|           |       | ( 8)  | ( 6)  | ( 4)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| EMXI      | *     | *     | 102 ( | 156 ( |       |       |       |
|           | *25** | *57** | 6)    | 5)    |       |       |       |
|           | ( 9)  | ( 8)  |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMD      | 45    | 97 (  | 155 ( | 223 ( | 378 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMM      | 34    | 76 (  | 142 ( | 227 ( | 357 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMS      | 45    | 101 ( | 160 ( | 235 ( | 326 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| LBAR      | 35    | 71 (  | 102 ( | 153 ( | 261 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| TVCN      | 32    | *     | *     | **    | *     |       |       |
|           | (11)  | *57** | *86** | 111** | *96** |       |       |
|           |       | ( 9)  | ( 7)  | ( 5)  | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GUNA      | 33 (  | *     | *     | *     |       |       |       |
|           | 9)    | *50** | *53** | *69** |       |       |       |
|           |       | ( 6)  | ( 4)  | ( 2)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | *     | *     | *     | **    |       |       |       |
|           | *30** | *48** | *60** | 110** |       |       |       |
|           | ( 9)  | ( 7)  | ( 4)  | ( 1)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 31    | 59 (  | 90 (  | 116 ( | 159 ( |       |       |
|           | (11)  | 9)    | 7)    | 5)    | 1)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NHC       | 31.9  | 55.1  | 77.4  | 97.9  | 136.2 | 180.1 | 226.1 |
| Official  | (     | (     | (979) | (849) | (620) | (439) | (293) |
|           | 1282) | 1129) |       |       |       |       |       |
| (         |       |       |       |       |       |       |       |
| 2003-2007 |       |       |       |       |       |       |       |
| mean)     |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

Table 4. Intensity forecast evaluation (heterogeneous sample) for
Tropical Storm Julio, 23-26 August 2008. Forecast errors (kt) are
followed by the number of forecasts in parentheses. Errors smaller than
the NHC official forecast are shown in boldface type.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Number    | For   |       |       |       |       |       |       |
| range     | ecast |       |       |       |       |       |       |
| CHAPTE    | P     |       |       |       |       |       |       |
| RForecast | eriod |       |       |       |       |       |       |
| Technique | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OCD5      | 4.6   | **    | **    | **    | 23.0  |       |       |
|           | (11)  | 2.8** | 2.7** | 3.4** | ( 1)  |       |       |
|           |       | ( 9)  | ( 7)  | ( 5)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GHMI      | 6.2   | 10.4  | 12.0  | 8.8 ( | **    |       |       |
|           | (11)  | ( 9)  | ( 7)  | 5)    | 5.0** |       |       |
|           |       |       |       |       | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| HWFI      | 5.2   | 8.7 ( | 11.1  | 9.8 ( | **    |       |       |
|           | (11)  | 9)    | ( 7)  | 5)    | 9.0** |       |       |
|           |       |       |       |       | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| LGEM      | 5.4   | 4.4 ( | 4.3 ( | 4.8 ( | 17.0  |       |       |
|           | (11)  | 9)    | 7)    | 5)    | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| DSHP      | 5.5   | **    | 7.9 ( | 10.4  | 25.0  |       |       |
|           | (11)  | 3.7** | 7)    | ( 5)  | ( 1)  |       |       |
|           |       | ( 9)  |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | 5.3 ( | **    | 5.5 ( | **    |       |       |       |
|           | 9)    | 3.4** | 4)    | 3.0** |       |       |       |
|           |       | ( 7)  |       | ( 1)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| ICON      | 5.2   | 5.8 ( | 6.1 ( | 4.2 ( | 10.0  |       |       |
|           | (11)  | 9)    | 7)    | 5)    | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 2.7   | 4.4 ( | 3.6 ( | 4.0 ( | 10.0  |       |       |
|           | (11)  | 9)    | 7)    | 5)    | ( 1)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NHC       | 6.2   | 10.4  | 13.9  | 16.3  | 18.7  | 19.2  | 19.1  |
| Official  | (     | (     | (979) | (848) | (620) | (439) | (293) |
|           | 1282) | 1129) |       |       |       |       |       |
| (         |       |       |       |       |       |       |       |
| 2003-2007 |       |       |       |       |       |       |       |
| mean)     |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

Number range CHAPTERTable 5. Watch and warning summary for Tropical
Storm Julio, 23-26 August 2008.

  ----------- ------------------------------- ------------------------------
  Date/Time   Action                          Location
  (UTC)                                       

  23 / 2100   Tropical Storm Watch issued     Santa Fe to Buenavista

  24 / 0300   Tropical Storm Watch modified   Santa Fe to Bahia Magdalena
              to                              

  24 / 0300   Tropical Storm Watch issued     San Evaristo to Loreto

  24 / 0300   Tropical Storm Warning issued   Santa Fe to San Evaristo

  24 / 0900   Tropical Storm Watch modified   Punta Abreojos to Bahia
              to                              Magdalena

  24 / 0900   Tropical Storm Watch modified   Mulege to Loreto
              to                              

  24 / 0900   Tropical Storm Warning          Santa Fe to San Evaristo
              discontinued                    

  24 / 0900   Tropical Storm Warning issued   Bahia Magdalena to Loreto

  24 / 1500   Tropical Storm Watch modified   Punta Abreojos to El Pocito
              to                              

  24 / 1500   Tropical Storm Watch modified   Mulege to Bahia San Juan
              to                              Bautista

  24 / 1500   Tropical Storm Warning          Bahia Magdalena to Loreto
              discontinued                    

  24 / 1500   Tropical Storm Warning issued   Punta Abreojos to Mulege

  25 / 0900   Tropical Storm Warning modified Punta Abreojos to Santa Fe
              to                              

  25 / 1500   Tropical Storm Watch            Mulege to Bahia San Juan
              discontinued                    Bautista

  25 / 1500   Tropical Storm Warning modified Punta Abreojos to Puerto San
              to                              Andresito

  25 / 1500   Tropical Storm Warning          La Paz to Mulege
              discontinued                    

  25 / 1500   Tropical Storm Warning issued   Loreto to Bahia de Los Angeles

  25 / 1500   Tropical Storm Warning issued   Guaymas to Puerto Libertad

  25 / 2100   Tropical Storm Watch            All
              discontinued                    

  25 / 2100   Tropical Storm Warning          Punta Abreojos to Puerto San
              discontinued                    Andresito

  26 / 0000   Tropical Storm Warning          All
              discontinued                    
  ----------- ------------------------------- ------------------------------

![](media/image1.jpeg){width="7.7659722222222225in"
height="6.000694444444444in"}

Number range CHAPTERFigure 1. Best track positions for Tropical Storm
Julio, 23-26 August 2008.

![](media/image2.wmf){width="7.111111111111111in" height="4.875in"}

Number range CHAPTERFigure 2. Selected wind observations and best track
maximum sustained surface wind speed curve for Tropical Storm Julio,
23-26 August 2008. Dashed vertical lines correspond to 0000 UTC.
Landfall in southern Baja California is indicated by the thin solid
vertical line.

![](media/image3.wmf){width="7.097222222222222in" height="4.875in"}

Number range CHAPTERFigure 3. Selected pressure observations and best
track minimum central pressure curve for Tropical Storm Julio, 23-26
August 2008. Dashed vertical lines correspond to 0000 UTC. Landfall in
southern Baja California is indicated by the thin solid vertical line.

Number range CHAPTER

[^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.