Tropical Cyclone Report

Tropical Storm Cristina

(EP032008)

27-30 June 2008

Richard J. Pasch

National Hurricane Center

18 February 2009

Cristina was an uneventful tropical cyclone that remained well offshore.

a.  Synoptic History

    The genesis of Cristina can be traced back to a tropical wave that
    crossed Central America on 21 June and moved over the eastern North
    Pacific Ocean by 22 June. An area of showers and thunderstorms
    associated with the wave moved westward within the ITCZ with little
    change in organization for several days. By 1200 UTC 26 June,
    several curved bands of deep convection became evident, and the
    system received its first Dvorak satellite classification at that
    time. Over the next day or so, the system's cloud pattern continued
    to become a little better organized, but NASA QuikSCAT data showed
    that the surface circulation was not yet sufficiently well-defined
    to warrant its designation as a tropical cyclone. By 1800 UTC 27
    June, however, visible satellite imagery indicated that the
    low-level circulation had become more distinct, and it is estimated
    that a tropical depression formed while centered nearly 900 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].

    The depression moved west-northwestward and strengthened into a
    tropical storm by 1200 UTC 28 June. Mid-level high pressure
    intensified to the north of Cristina, and the tropical cyclone
    turned toward the west. Vertical wind shear was not very strong over
    the area but, since it was situated in a relatively stable air mass
    and over marginal sea surface temperatures of about 26ºC, Cristina
    was not able to strengthen much. The storm reached its estimated
    peak intensity of 45 kt later on 28 June. This intensity was more or
    less maintained until around 0600 UTC 29 June, by which time the
    cyclone began to weaken, apparently due to an increasingly stable
    air mass and greater easterly vertical wind shear. Over the next day
    or so, Cristina produced some bursts of deep convection but became
    mostly devoid of banding features while its maximum winds gradually
    declined. By 1200 UTC 30 June, the system had lost most of its deep
    convection, and it is estimated that the cyclone weakened to a
    tropical depression. A little later that day, the depression
    degenerated into a remnant low pressure area that continued heading
    westward. On 2 July, the low turned southwestward and
    south-southwestward, and it dissipated on 3 July about 1700 n mi
    west-southwest of the southern tip of Baja California.

b.  Meteorological Statistics

    Observations in Cristina (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). 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 Cristina. The maximum intensity of
    Cristina is based on Dvorak estimates from TAFB and SAB as well as
    QuikSCAT data. Cristina's minimum pressure is estimated to have
    occurred at 0000 UTC 29 June, at which time the storm appeared to be
    the best organized on satellite images.

    No ship reports of tropical-storm-force winds associated with
    Cristina have been received.

c.  Casualty and Damage Statistics

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

d.  Forecast and Warning Critique

    Cristina's genesis was not anticipated especially far in advance.
    The area of disturbed weather that developed into Cristina was not
    mentioned in the Tropical Weather Outlook (TWO) until 30 h prior to
    genesis, at which time the formation probability was assigned to the
    "low" category. Eighteen hours prior to genesis, it was acknowledged
    in the TWO that the system could develop into a tropical depression,
    and the formation probability was boosted into the "medium" range.
    Six hours later, 12 h before genesis, the probability was set to the
    "high" range.

    A verification of official and guidance model track forecasts is
    given in Table 2. Average official track errors for Cristina were
    19, 36, 51, and 63 n mi for the 12, 24, 36, and 48 h forecasts,
    respectively. The number of forecasts ranged from 10 at 12 h to 4 at
    48 h; there were no forecasts verifying at 72, 96, or 120 h. It can
    be seen that the mean official track forecast errors for Cristina
    were lower than the average 5-yr official track errors (Table 2).
    Some of the numerical guidance had even lower track errors, however
    it should be noted that the number of verifying cases is quite
    small.

    A verification of official and guidance model intensity forecasts is
    given in Table 3. Average official intensity errors were 8, 7, 7,
    and 5 kt for the 12, 24, 36, and 48 h forecasts, respectively. For
    comparison, the average 5-yr official intensity errors are 6, 10,
    14, and 16 kt, respectively. None of the official intensity
    forecasts called for significant strengthening of this tropical
    cyclone, which proved to be a correct expectation.

Watches or warnings were neither required nor issued for Cristina.

Table 1. Best track for Tropical Storm Cristina, 27-30 June 2008.

+---------+--------+---------+---------+---------+------------------+
| Da      | La     | Lo      | P       | Wind    | Stage            |
| te/Time | titude | ngitude | ressure | Speed   |                  |
|         |        |         |         |         |                  |
| (UTC)   | \(N\)  | \(W\)   | (mb)    | (kt)    |                  |
+---------+--------+---------+---------+---------+------------------+
| 27 /    | 13.5   | 122.0   | 1007    | 30      | tropical         |
| 1800    |        |         |         |         | depression       |
+---------+--------+---------+---------+---------+------------------+
| 28 /    | 13.9   | 122.7   | 1006    | 30      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 28 /    | 14.2   | 123.5   | 1006    | 30      | \"               |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 28 /    | 14.4   | 124.3   | 1005    | 35      | tropical storm   |
| 1200    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 28 /    | 14.6   | 125.0   | 1000    | 45      | \"               |
| 1800    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 29 /    | 14.6   | 125.7   | 999     | 45      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 29 /    | 14.6   | 126.4   | 1000    | 45      | \"               |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 29 /    | 14.5   | 127.1   | 1002    | 40      | \"               |
| 1200    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 29 /    | 14.4   | 127.9   | 1002    | 40      | \"               |
| 1800    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 30 /    | 14.3   | 128.8   | 1002    | 40      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 30 /    | 14.3   | 129.7   | 1002    | 40      | \"               |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 30 /    | 14.2   | 130.7   | 1005    | 30      | tropical         |
| 1200    |        |         |         |         | depression       |
+---------+--------+---------+---------+---------+------------------+
| 30 /    | 14.1   | 131.7   | 1007    | 30      | low              |
| 1800    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 01 /    | 14.1   | 132.7   | 1008    | 25      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 01 /    | 14.1   | 133.7   | 1009    | 20      | \"               |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 01 /    | 14.1   | 134.5   | 1009    | 20      | \"               |
| 1200    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 01 /    | 14.0   | 135.3   | 1009    | 20      | \"               |
| 1800    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 02 /    | 13.8   | 136.0   | 1009    | 20      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 02 /    | 13.5   | 136.5   | 1009    | 20      | \"               |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 02 /    | 13.1   | 136.9   | 1009    | 20      | \"               |
| 1200    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 02 /    | 12.8   | 137.1   | 1009    | 20      | \"               |
| 1800    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 03 /    | 12.5   | 137.2   | 1009    | 20      | \"               |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 03 /    |        |         |         |         | dissipated       |
| 0600    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+
| 29 /    | 14.6   | 125.7   | 999     | 45      | minimum pressure |
| 0000    |        |         |         |         |                  |
+---------+--------+---------+---------+---------+------------------+

Table 2. Track forecast evaluation (heterogeneous sample) for Tropical
Storm Cristina, 27-

> 30 June 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.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Forecast  | For   |       |       |       |       |       |       |
| Technique | ecast |       |       |       |       |       |       |
|           | P     |       |       |       |       |       |       |
|           | eriod |       |       |       |       |       |       |
|           | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CLP5      | 32    | 62 (  | 109 ( | 134 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDI      | 22    | 37 (  | *     | 67 (  |       |       |       |
|           | (10)  | 8)    | *45** | 4)    |       |       |       |
|           |       |       | ( 6)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| HWFI      | 38    | 67 (  | 91 (  | 108 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSI      | 25    | *     | *     | 66 (  |       |       |       |
|           | (10)  | *34** | *47** | 4)    |       |       |       |
|           |       | ( 8)  | ( 6)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| AEMI      | 29    | *     | *     | *     |       |       |       |
|           | (10)  | *35** | *35** | *55** |       |       |       |
|           |       | ( 8)  | ( 6)  | ( 4)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPI      | 42 (  | 72 (  | 101 ( | 139 ( |       |       |       |
|           | 2)    | 2)    | 2)    | 2)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKMI      | 23 (  | 58 (  | 192 ( | 599 ( |       |       |       |
|           | 8)    | 6)    | 4)    | 2)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| EGRI      | 21 (  | 47 (  | 84 (  |       |       |       |       |
|           | 8)    | 6)    | 4)    |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| EMXI      | *     | *     | *     | *     |       |       |       |
|           | *10** | *24** | *29** | *11** |       |       |       |
|           | ( 5)  | ( 4)  | ( 3)  | ( 2)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMD      | 43    | 81 (  | 122 ( | 162 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMM      | 35    | 68 (  | 102 ( | 149 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMS      | 46    | 91 (  | 147 ( | 209 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| LBAR      | 33    | 85 (  | 160 ( | 218 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| TVCN      | 22    | *     | *     | *     |       |       |       |
|           | (10)  | *31** | *35** | *39** |       |       |       |
|           |       | ( 8)  | ( 6)  | ( 4)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | 19 (  | 36 (  | 72 (  | 221 ( |       |       |       |
|           | 7)    | 5)    | 3)    | 1)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 19    | 36 (  | 51 (  | 63 (  |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| 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 3. Intensity forecast evaluation (heterogeneous sample) for
Tropical Storm Cristina, 27-30 June 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.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Forecast  | For   |       |       |       |       |       |       |
| Technique | ecast |       |       |       |       |       |       |
|           | P     |       |       |       |       |       |       |
|           | eriod |       |       |       |       |       |       |
|           | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OCD5      | **    | 7.9 ( | 8.8 ( | 5.3 ( |       |       |       |
|           | 6.9** | 8)    | 6)    | 4)    |       |       |       |
|           | (10)  |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GHMI      | **    | 7.3 ( | **    | **    |       |       |       |
|           | 7.0** | 8)    | 6.2** | 4.5** |       |       |       |
|           | (10)  |       | ( 6)  | ( 4)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| HWFI      | **    | **    | **    | 5.3 ( |       |       |       |
|           | 4.7** | 6.1** | 4.5** | 4)    |       |       |       |
|           | (10)  | ( 8)  | ( 6)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| LGEM      | 7.7   | 9.3 ( | 9.7 ( | 8.8 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| DSHP      | **    | **    | **    | **    |       |       |       |
|           | 6.1** | 4.9** | 4.5** | 2.0** |       |       |       |
|           | (10)  | ( 8)  | ( 6)  | ( 4)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | **    | **    | **    | **    |       |       |       |
|           | 6.4** | 3.2** | 5.7** | 2.0** |       |       |       |
|           | ( 7)  | ( 5)  | ( 3)  | ( 1)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| ICON      | **    | **    | **    | 5.0 ( |       |       |       |
|           | 5.9** | 5.5** | 5.5** | 4)    |       |       |       |
|           | (10)  | ( 8)  | ( 6)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 7.5   | 6.9 ( | 6.7 ( | 5.0 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| 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)     |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

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

Figure 1. Best track positions for Tropical Storm Cristina, 27-30 June
2008.

![](media/image2.wmf){width="7.069444444444445in"
height="4.819444444444445in"}

Figure 2. Selected wind observations and best track maximum sustained
surface wind speed curve for Tropical Storm Cristina, 27-30 June 2008.
Dashed vertical lines correspond to 0000 UTC.

![](media/image3.wmf){width="7.055555555555555in"
height="4.819444444444445in"}

Figure 3. Selected pressure observations and best track minimum central
pressure curve for Tropical Storm Cristina, 27-30 June 2008. 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.