Number range CHAPTERTropical Cyclone Report

Tropical Storm Gamma

14-21 November 2005

Stacy R. Stewart

National Hurricane Center

24 November 2005

Tropical Storm Gamma was a late season tropical cyclone that produced
locally heavy rainfall and floods in Honduras and Belize that caused 37
deaths.

a\. Synoptic History

A vigorous tropical wave moved off the west coast of Africa on 3
November and continued westward across the tropical Atlantic Ocean. For
such a late season system, the wave maintained an unusually large amount
of deep convection along and east of the wave axis until it reached the
Windward Islands 10 days later. The sharp wave produced wind gusts to
near tropical storm-force and locally heavy rainfall as it passed across
the southern Windward Islands on 13 November. A broad and poorly-defined
low pressure system developed along the southern portion of the wave
axis late that same day when the system was located over the extreme
southeastern Caribbean Sea. Deep convection had previously been
displaced a couple hundred miles to the east due to moderate easterly
shear, now began to develop close to the center of the surface low
pressure system, and it is estimated that a tropical depression formed
at 0000 UTC 14 November about 85 n mi west of St. Vincent. 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.

Tropical Depression Twenty-Seven continued on a westward track at 10-15
kt and became better organized despite moderate upper-level westerly
wind shear. Based on ship reports well to the northeast of the center
indicating winds just below tropical storm strength, and Dvorak
satellite intensity estimates of T2.5 or 35 kt, it is estimated that the
cyclone reached tropical storm strength at 0600 UTC 15 November.
However, this newly-acquired status was relatively short-lived as the
westerly vertical shear continued to increase, causing Tropical Storm
Gamma to weaken to a depression by 1800 UTC that same day, and
degenerate into a tropical wave 24 hours later when the system was
located about 265 n mi southeast of Jamaica. A deep-layer subtropical
high pressure ridge over the southwestern Atlantic Ocean and Gulf of
Mexico forced the remnants of Gamma westward at 20-22 kt across the
central Caribbean Sea before the system slowed down across the western
Caribbean Sea and eastern Honduras on 17 November.

While the remnants of Gamma were racing westward across the Caribbean
Sea, a broad but well-defined low pressure system formed over Panama and
moved northwestward over the southwestern Caribbean Sea and into
northeastern Nicaragua on 16 November. That low pressure system
continued its slow northwestward motion across Nicaragua and gradually
merged or interacted with the remnants of Gamma over the mountainous
terrain of east-central Honduras early on 18 November. It is estimated
that Gamma regenerated into a tropical storm at 1800 UTC 18 November
along the northern coast of Honduras near Limon. While the other low
pressure system likely aided the regeneration of Gamma, it is difficult
to determine precisely whether the remnant circulation of Gamma
entrained the non-convective low pressure system, or vice versa, due to
the complex interaction between the two systems over the elevated
terrain (many areas exceed elevations of 6000 ft) of interior Honduras.
However, deep convection associated with the remnant low- to mid-level
vorticity center of Gamma maintained continuity throughout its lifetime,
and it is estimated that the low-level circulation of the other low
merged with the remnant low- to mid-level circulation of Gamma. This
scenario was also forecast by several of the global and regional
computer models and is, therefore, accepted as the most likely evolution
of the regeneration of Gamma.

Gamma drifted northward over the northwestern Caribbean Sea and slowly
strengthened, reaching its peak intensity of 45 kt when it was located
just east of Roatan Island at around 1200 UTC 19 November (Fig. 4).
Later that day, Gamma began a slow drift to the east, and on 20 November
began moving more quickly to the southeast. Moderate upper-level
southerly shear gradually shifted around to the northwest and displaced
most of the convection well to the southeast of the low-level center.
This caused Gamma to weaken to a depression around 1200 UTC that day.
The cyclone continued to rapidly weaken and degenerated into a
non-convective remnant low pressure system early on 21 November, and
dissipated by 0600 UTC on 22 November just east of Honduras-Nicaragua
border.

b.  Meteorological Statistics

    Observations in Tropical Storm Gamma (Figs. 2 and 3) include
    satellite-based Dvorak technique intensity estimates from the
    Tropical Analysis and Forecast Branch (TAFB), the Satellite Analysis
    Branch (SAB) and the U. S. Air Force Weather Agency (AFWA), as well
    as flight-level observations from flights of the 53^rd^ Weather
    Reconnaissance Squadron (WRS) of the U. S. Air Force Reserve
    Command. Microwave satellite imagery from NOAA polar-orbiting
    satellites, the NASA Tropical Rainfall Measuring Mission (TRMM), the
    NASA QuikSCAT, and Defense Meteorological Satellite Program (DMSP)
    satellites were also useful in tracking Gamma.

    The 53^rd^ WRS made a total of six fixes on Gamma when the cyclone
    had moved into the northwestern Caribbean Sea. Three investigative
    missions were also performed on 15, 17, and 18 November. The maximum
    flight-level winds measured at 1500 ft were 56 kt at 2155 UTC 18
    November on the west side of the circulation about midway between
    Roatan Island and the northern Honduras coast. The standard
    adjustment factor of 0.80 would normally yield an equivalent surface
    wind of 45 kt. However, the lack of deep convection in the western
    semicircle at that time likely prevented those winds from mixing
    down to the surface. But by early on 19 November, convection
    developed west through north of the surface center (Fig. 4) and
    those stronger flight-level winds appear to have mixed down to the
    surface based on a 1-minute surface wind report of 43 kt on Roatan
    Island, Honduras at 0730 UTC. The flight-level equivalent surface
    wind and the wind report from Roatan Island are the basis for the
    peak intensity of 45 kt.

    Selected ship and buoy reports associated with Tropical Storm Gamma
    are given in Table 2, and selected surface observations from land
    stations are given in Table 3.

    Most ships avoided Gamma's tropical storm-force winds. However,
    early on 18 November, NOAA buoy 42057 and an unknown ship reported
    35-kt winds in the northeastern quadrant of Gamma's circulation.

    No significant storm surge was reported due to Gamma's relatively
    weak intensity. While considerable heavy rainfall-induced inland
    flooding was reported over Honduras and Belize, no official rainfall
    reports were available. There was, however, one unofficial rainfall
    total of 4.44 in reported on Roatan Island, Honduras.

c.  Casualty and Damage Statistics

    Reports from the Government of Honduras and news media indicate
    there were a total of 37 deaths associated with Tropical Storm Gamma
    -- 34 deaths in Honduras and 3 in Belize. The deaths were the result
    of flash floods and mud slides caused by heavy rainfall. In
    addition, 13 people were missing in Honduras. News reports from the
    Associated Press further indicate that "Gamma's rains and winds
    affected more than 100,000 Hondurans, damaging their homes, cutting
    off their electricity, and leaving them without food and water." The
    flooding destroyed 10 bridges and damaged 7 more in Honduras, and
    decimated more than 5,200 acres of banana crops. While no official
    damage estimates have been received, reports from private companies
    indicate banana crop losses were US\$13-18 million.

d.  Forecast and Warning Critique

    Average official track errors (with the number of cases in
    parentheses) for Tropical Storm Gamma were 49 (17), 96 (13), 137
    (9), 161 (5), 267 (2), 285 (6), and 263 (9) n mi for the 12, 24, 36,
    48, 72, 96, and 120 h forecasts, respectively. These errors are
    greater than the average official track errors for the 10-yr period
    1995-2004[^1] \[(42, 75, 107, 138, 202, 236, and 310 n mi,
    respectively), (Table 4)\]. While the absolute track forecast errors
    were larger than average, the cross-track errors were relatively
    low. The significant increase in forward speed early in Gamma's
    lifetime was not anticipated by the official forecasts. After Gamma
    regenerated over the western Caribbean Sea, large track errors were
    the result of official forecasts taking the cyclone northeastward
    out of the Caribbean region and toward South Florida. The low- to
    mid-level high pressure ridge to the north was forecast by several
    of the NHC models, especially the GFDL model, which was to allow
    Gamma to move northward and then northeastward across western Cuba
    and the southern Florida Peninsula or the Florida Straits. In
    contrast, the ridge to the north remained intact, which kept Gamma
    over the northwestern Caribbean Sea and under the influence of
    significant vertical wind shear.

    Average official intensity errors were 3, 7, 12, 17, 18, 23, and 26
    kt for the 12, 24, 36, 48, 72, 96, and 120 h forecasts,
    respectively. For comparison, the average official intensity errors
    over the 10-yr period 1995-2004 are 6, 10, 12, 15, 18, 20, and 22
    kt, respectively. The slightly larger than average intensity
    forecast errors were due to Gamma forecast to reach minimal
    hurricane strength rather than weaken and eventually degenerate into
    a tropical wave due to stronger than expected vertical wind shear.
    However, intensity forecast errors by the SHIPS and GFDL intensity
    models were as large or larger, with the GFDL model forecasting
    Gamma to become a major hurricane three times.

Number range CHAPTERTable 1. Best track for Tropical Storm Gamma, 14-21
November 2005.

+----------+---+------+--------+--------+----------+---------------------+
| D        | L |      | Lon    | Pr     | Wind     | Stage               |
| ate/Time | a |      | gitude | essure | Speed    |                     |
|          | t |      |        |        |          |                     |
| (UTC)    | i |      | (^^W) | (mb)   | (kt)     |                     |
|          | t |      |        |        |          |                     |
|          | u |      |        |        |          |                     |
|          | d |      |        |        |          |                     |
|          | e |      |        |        |          |                     |
|          |   |      |        |        |          |                     |
|          | ( |      |        |        |          |                     |
|          | ^ |      |        |        |          |                     |
|          |  |      |        |        |          |                     |
|          | ^ |      |        |        |          |                     |
|          | N |      |        |        |          |                     |
|          | ) |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 14 /     |   | 13.2 | 62.1   | 1007   | 30       | tropical depression |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 14 /     |   | 13.6 | 62.8   | 1006   | 30       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 14 /     |   | 13.8 | 63.4   | 1006   | 30       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 14 /     |   | 14.1 | 64.2   | 1005   | 30       | \"                  |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 15 /     |   | 14.2 | 65.0   | 1004   | 30       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 15 /     |   | 14.3 | 66.0   | 1004   | 35       | tropical storm      |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 15 /     |   | 14.4 | 67.1   | 1004   | 35       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 15 /     |   | 14.7 | 68.4   | 1005   | 30       | tropical depression |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 16 /     |   | 14.8 | 69.9   | 1006   | 30       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 16 /     |   | 14.8 | 71.5   | 1006   | 30       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 16 /     |   | 14.7 | 73.1   | 1006   | 25       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 16 /     |   | 14.8 | 75.4   | 1006   | 25       | tropical wave       |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 17 /     |   | 15.0 | 77.6   | 1007   | 25       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 17 /     |   | 15.3 | 79.7   | 1008   | 25       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 17 /     |   | 15.6 | 81.7   | 1007   | 30       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 17 /     |   | 15.8 | 83.1   | 1007   | 30       | \"                  |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 18 /     |   | 15.8 | 84.1   | 1007   | 30       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 18 /     |   | 15.7 | 84.8   | 1006   | 30       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 18 /     |   | 15.5 | 85.5   | 1006   | 30       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 18 /     |   | 15.7 | 85.6   | 1006   | 35       | tropical storm      |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 19 /     |   | 16.0 | 85.6   | 1005   | 40       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 19 /     |   | 16.1 | 85.6   | 1004   | 40       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 19 /     |   | 16.1 | 85.4   | 1002   | 45       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 19 /     |   | 16.2 | 85.2   | 1004   | 40       | \"                  |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 20 /     |   | 16.4 | 85.0   | 1005   | 40       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 20 /     |   | 16.6 | 85.0   | 1006   | 35       | \"                  |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 20 /     |   | 16.7 | 85.2   | 1007   | 30       | tropical depression |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 20 /     |   | 16.9 | 85.5   | 1007   | 30       | \"                  |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 21 /     |   | 17.1 | 85.5   | 1008   | 25       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 21 /     |   | 17.0 | 85.2   | 1008   | 25       | remnant low         |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 21 /     |   | 16.7 | 84.8   | 1008   | 25       | \"                  |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 21 /     |   | 16.4 | 84.3   | 1009   | 25       | \"                  |
| 1800     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 22 /     |   | 15.4 | 83.5   | 1009   | 25       | \"                  |
| 0000     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 22 /     |   |      |        |        |          | dissipated          |
| 0600     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+
| 19 /     |   | 16.1 | 85.4   | 1002   | 45       | minimum pressure    |
| 1200     |   |      |        |        |          |                     |
+----------+---+------+--------+--------+----------+---------------------+

Number range CHAPTERTable 2. Selected ship and buoy reports for Tropical
Storm Gamma, 14-21 November 2005.

+----------+----------+----------+-----------+-----------+-----------+
| D        | Ship     | Latitude | Longitude | Wind      | Pressure  |
| ate/Time | call     |          |           |           |           |
| (UTC)    | sign     | (^o^N)   | (^o^W)    | dir/speed | (mb)      |
|          |          |          |           | (kt)      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 14 /     | ZCBU6    | 14.4     | 61.1      | 120 / 27  |           |
| 0000     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 14 /     | V7CY9    | 15.6     | 63.9      | 110 / 29  | 1005.5    |
| 2000     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 14 /     | V7CY9    | 15.0     | 63.8      | 110 / 30  | 1006.6    |
| 2300     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 15 /     | V7CY9    | 13.7     | 65.6      | 120 / 31  | 1007.6    |
| 1500     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 15 /     | C6PZ3    | 13.7     | 64.5      | 120 / 30  |           |
| 1500     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 15 /     | C6PZ3    | 14.0     | 65.1      | 130 / 32  |           |
| 1800     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 15 /     | C6PZ3    | 14.2     | 65.9      | 110 / 31  |           |
| 2100     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 16 /     | C6KD4    | 15.1     | 73.2      | 060 / 30  | 1008.8    |
| 0600     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 17 /     | Buoy     | 17.6     | 80.8      | 080 / 33  |           |
| 1230     | 42057    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 17 /     | Buoy     | 17.6     | 80.8      | 080 / 31  |           |
| 1530     | 42057    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 17 /     | Buoy     | 17.6     | 80.8      | 070 / 31  |           |
| 2330     | 42057    |          |           | G 35      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      | 070 / 33  |           |
| 0345     | 42057    |          |           | G 37      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 19.9     | 85.1      | 035 / 31  |           |
| 0130     | 42056    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | ZCDF4    | 17.9     | 80.6      | 100 / 32  | 1009.4    |
| 0600     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      | 070 / 35  |           |
| 0635     | 42057    |          |           | G 39      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      |           | 1008.4    |
| 0750     | 42057    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      | 105 / 33  |           |
| 0825     | 42057    |          |           | G 37      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      | 101 / 31  |           |
| 0820     | 42057    |          |           | G 39      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 19.9     | 85.1      |           | 1010.5    |
| 0850     | 42056    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | KS049    | 18.3     | 87.6      | 030 / 30  |           |
| 0900     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | SHIP     | 19.2     | 83.0      | 040 / 35  | 1010.7    |
| 1200     |          |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 19.9     | 85.1      | 053 / 31  |           |
| 1540     | 42056    |          |           | G 41      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 18 /     | Buoy     | 17.6     | 80.8      |           | 1008.5    |
| 2050     | 42057    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+
| 19 /     | Buoy     | 17.6     | 80.8      | 106 / 27  |           |
| 0020     | 42057    |          |           | G 35      |           |
+----------+----------+----------+-----------+-----------+-----------+
| 19 /     | Buoy     | 19.9     | 85.1      |           | 1010.3    |
| 0950     | 42056    |          |           |           |           |
+----------+----------+----------+-----------+-----------+-----------+

G peak gust

Number range CHAPTERTable 3. Selected surface observations for Tropical
Storm Gamma, 14-21 November 2005.

+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+
| Location        | M   |     | M   |       |     | St  | St  | To  |
|                 | ini |     | axi |       |     | orm | orm | tal |
|                 | mum |     | mum |       |     | su  |     |     |
|                 | Sea |     | S   |       |     | rge | t   | r   |
|                 | Le  |     | urf |       |     |     | ide | ain |
|                 | vel |     | ace |       |     | (   |     |     |
|                 | Pr  |     |     |       |     | ft) | (   | (   |
|                 | ess |     | W   |       |     | ^c^ | ft) | in) |
|                 | ure |     | ind |       |     |     | ^d^ |     |
|                 |     |     | Sp  |       |     |     |     |     |
|                 |     |     | eed |       |     |     |     |     |
+=================+=====+=====+=====+=======+=====+=====+=====+=====+
|                 | Da  | Pre | Da  | Sust  | G   |     |     |     |
|                 | te/ | ss. | te/ | ained | ust |     |     |     |
|                 |     |     |     |       |     |     |     |     |
|                 | t   | (   | t   | (k    | (   |     |     |     |
|                 | ime | mb) | ime | t)^b^ | kt) |     |     |     |
|                 |     |     |     |       |     |     |     |     |
|                 | (U  |     | (U  |       |     |     |     |     |
|                 | TC) |     | TC) |       |     |     |     |     |
|                 |     |     | ^a^ |       |     |     |     |     |
+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+
| Grantley Adams  | 1   | 100 | 1   | 27    |     |     |     |     |
| IAP (TBPB),     | 3/2 | 8.0 | 4/0 |       |     |     |     |     |
| Bridgetown,     | 000 |     | 100 |       |     |     |     |     |
| Barbados        |     |     |     |       |     |     |     |     |
+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+
| Hewanorra IAP   | 1   | 100 | 1   | 29    | 33  |     |     |     |
| (TLPL), St.     | 3/2 | 7.0 | 4/0 |       |     |     |     |     |
| Lucia           | 100 |     | 000 |       |     |     |     |     |
+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+
| Roatan,         | 1   | 100 | 1   | 42    |     |     |     |     |
| Honduras (Lago  | 8/2 | 1.8 | 9/0 |       |     |     |     |     |
| Vista Scuba,    | 200 |     | 615 |       |     |     |     |     |
| Inc. unofficial |     |     |     |       |     |     |     |     |
| observation)    |     |     |     |       |     |     |     |     |
+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+
| Roatan,         | 1   | 100 | 1   | 43    |     |     |     | 4   |
| Honduras (Lago  | 9/0 | 2.7 | 9/0 |       |     |     |     | .44 |
| Vista Scuba,    | 730 |     | 730 |       |     |     |     |     |
| Inc. unofficial |     |     |     |       |     |     |     |     |
| observation)    |     |     |     |       |     |     |     |     |
+-----------------+-----+-----+-----+-------+-----+-----+-----+-----+

^a^ Date/time is for sustained wind when both sustained and gust are
listed.

^b^ Except as noted, sustained wind averaging periods for C-MAN and
land-based ASOS reports are 2 min; buoy averaging periods are 8 min.

^c^ Storm surge is water height above normal astronomical tide level.

^d^ Storm tide is water height above National Geodetic Vertical Datum
(1929 mean sea level).

Number range CHAPTERTable 4. Preliminary forecast evaluation
(heterogeneous sample) for Tropical Storm

Gamma, 14-21 November 2005. Forecast errors (n mi) are followed by the
number of forecasts

in parentheses. Errors smaller than the NHC official forecast are shown
in bold-face type.

Verification includes the depression stage, but does not include the
extratropical stage, if any.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Number    | For   |       |       |       |       |       |       |
| range     | ecast |       |       |       |       |       |       |
| CHAPTE    | P     |       |       |       |       |       |       |
| RForecast | eriod |       |       |       |       |       |       |
| Technique | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CLP5      | 53    | 102   | 153 ( | 197 ( | 338 ( | 509 ( | 665 ( |
|           | (17)  | (13)  | 9)    | 5)    | 4)    | 8)    | 9)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFNI      | 51    | *     |       |       | 482 ( | 374 ( | 334 ( |
|           | (10)  | *30** |       |       | 4)    | 5)    | 3)    |
|           |       | ( 3)  |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDI      | *     | *     | **    | **    | **    | **    | **    |
|           | *43** | *80** | 125** | 147** | 172** | 195** | 202** |
|           | (17)  | (13)  | ( 9)  | ( 5)  | ( 4)  | ( 8)  | ( 9)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDL\*    | *     | *     | **    | **    | **    | **    | **    |
|           | *39** | *76** | 104** | 119** | 175** | 181** | 211** |
|           | (17)  | (13)  | ( 9)  | ( 5)  | ( 3)  | ( 7)  | ( 9)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDN      | 63    | *     | **    |       | 383 ( | **    | 348 ( |
|           | (12)  | *82** | 125** |       | 3)    | 279** | 3)    |
|           |       | ( 5)  | ( 1)  |       |       | ( 5)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSI      | 51    | *     | **    | 176 ( | *     | *     |       |
|           | (13)  | *83** | 131** | 2)    | *17** | *42** |       |
|           |       | (11)  | ( 7)  |       | ( 1)  | ( 1)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSO\*    | 64    | 103 ( | **    | 190 ( | *     | *     |       |
|           | (11)  | 9)    | 128** | 2)    | *83** | *58** |       |
|           |       |       | ( 7)  |       | ( 1)  | ( 1)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| AEMI      | 49    | *     | 154 ( | 178 ( |       |       |       |
|           | (15)  | *91** | 7)    | 3)    |       |       |       |
|           |       | (10)  |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPI      | 49    | *     | **    | 167 ( | **    | **    | **    |
|           | (14)  | *86** | 129** | 1)    | 191** | 237** | 261** |
|           |       | ( 9)  | ( 5)  |       | ( 4)  | ( 8)  | ( 7)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPS\*    | *     | *     | **    | **    | **    | **    | **    |
|           | *44** | *79** | 132** | 127** | 159** | 186** | 234** |
|           | (14)  | (10)  | ( 6)  | ( 2)  | ( 4)  | ( 8)  | ( 8)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKMI      | 51    | *     | *     | *     | **    | 370 ( | 360 ( |
|           | (15)  | *84** | *90** | *51** | 224** | 8)    | 7)    |
|           |       | (11)  | ( 7)  | ( 3)  | ( 4)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKM\*     | 61 (  | 104 ( | **    | **    | **    | 285 ( | 385 ( |
|           | 9)    | 7)    | 131** | 120** | 180** | 4)    | 5)    |
|           |       |       | ( 5)  | ( 3)  | ( 2)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| A98E      | 51    | *     | 145 ( | 213 ( | **    | **    | 294 ( |
|           | (17)  | *93** | 9)    | 5)    | 192** | 271** | 9)    |
|           |       | (13)  |       |       | ( 4)  | ( 8)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| A9UK      | 55 (  | *     | **    | 180 ( | **    |       |       |
|           | 8)    | *95** | 111** | 3)    | 243** |       |       |
|           |       | ( 6)  | ( 4)  |       | ( 2)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMD      | 87    | 180   | 294 ( | 392 ( | **    | 454 ( | 527 ( |
|           | (17)  | (13)  | 9)    | 5)    | 305** | 8)    | 9)    |
|           |       |       |       |       | ( 4)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMM      | 53    | 99    | 164 ( | 205 ( | **    | **    | **    |
|           | (17)  | (13)  | 9)    | 5)    | 140** | 133** | 247** |
|           |       |       |       |       | ( 4)  | ( 8)  | ( 9)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMS      | 60    | 111   | 156 ( | 163 ( | **    | **    | 416 ( |
|           | (17)  | (13)  | 9)    | 5)    | 101** | 279** | 9)    |
|           |       |       |       |       | ( 4)  | ( 8)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CONU      | *     | *     | **    | **    | **    | 285 ( | 272 ( |
|           | *41** | *72** | 107** | 114** | 257** | 8)    | 7)    |
|           | (17)  | (12)  | ( 8)  | ( 3)  | ( 4)  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GUNA      | *     | *     | **    |       | *     | *     |       |
|           | *33** | *68** | 111** |       | *79** | *98** |       |
|           | (10)  | ( 8)  | ( 4)  |       | ( 1)  | ( 1)  |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | *     | *     | **    | **    |       |       |       |
|           | *47** | *84** | 129** | 125** |       |       |       |
|           | ( 6)  | ( 5)  | ( 3)  | ( 1)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 49    | 96    | 137 ( | 161 ( | 267 ( | 285 ( | 263 ( |
|           | (17)  | (13)  | 9)    | 5)    | 2)    | 6)    | 9)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NHC       | 42    | 75    | 107   | 138   | 202   | 236   | 310   |
| Official  |       |       |       |       |       |       |       |
|           | \(3   | \(3   | \(2   | \(2   | \(2   | \(    | \(    |
| (         | 400\) | 116\) | 848\) | 575\) | 117\) | 649\) | 535\) |
| 1995-2004 |       |       |       |       |       |       |       |
| mean)     |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

\*Output from these models are unavailable at forecast time.

Errors given for the 96 and 120 h periods are averages over the
four-year period 2001-4

Number range CHAPTERTable 5. Watch and warning summary for Tropical
Storm Gamma, 14-21 November 2005.

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

  18 / 2100   Tropical Storm Warning       All Bay Islands of Honduras
              issued                       

  18 / 2100   Tropical Storm Warning       Entire Coast of Belize
              issued                       

  18 / 2100   Tropical Storm Watch issued  Eastern Yucatan, Mexico from
                                           Belize-Mexico border northward
                                           to Punta Allen

  19 / 0400   Tropical Storm Warning       Eastern Yucatan Coast from
              modified                     Belize-Mexico border northward
                                           to Punta Gruesa

  19 / 0400   Tropical Storm Watch         Eastern Yucatan. Mexico from
              modified                     north of Punta Gruesa northward
                                           to Tulum

  19 / 1500   Tropical Storm Warning       Southern Belize south of Belize
              discontinued                 City

  19 / 2100   Tropical Storm Warning       All of Belize
              discontinued                 

  19 / 2100   Tropical Storm Warning       All of Yucatan Peninsula, Mexico
              discontinued                 

  20 / 1500   Tropical Storm Warning       All Bay Islands of Honduras
              discontinued                 
  ----------- ---------------------------- --------------------------------

![](media/image1.wmf){width="6.498611111111111in"
height="5.000694444444444in"}

Number range CHAPTERFigure 1. Best track positions for Tropical Storm
Gamma, 14-21 November 2005.

![](media/image2.wmf){width="6.673611111111111in"
height="4.636111111111111in"}

Number range CHAPTERFigure 2. Selected wind observations and best track
maximum sustained surface wind speed

curve for Tropical Storm Gamma, 14-21 November 2005. Aircraft
observations have been

adjusted for elevation using an 80% adjustment factor for observations
from 850 mb and 1500 ft.

Objective Dvorak estimates represent linear averages over a three-hour
period ending on the

nominal observation time.

![](media/image3.wmf){width="6.673611111111111in"
height="4.636111111111111in"}

Number range CHAPTERFigure 3. Selected pressure observations and best
track minimum central pressure curve for

Tropical Storm Gamma, 14-21 November 2005. Objective Dvorak estimates
represent linear

averages over a three-hour period ending on the nominal observation
time.

![](media/image4.jpeg){width="4.0569444444444445in"
height="3.701388888888889in"}

![](media/image5.jpeg){width="4.0472222222222225in"
height="3.595833333333333in"}

Number range CHAPTERFigure 4. Passive microwave data (85 GHz channel) on
19 Nov 2005 of Gamma near its peak

intensity of 45 kt. The tight low-level circulation center can be seen
near 16^O^ N 85.5^O^ W, or just

offshore the north-central coast of Honduras, in the (a) 1009 UTC TRMM
and (b) 1205 UTC

SSMI images. (satellite imagery courtesy of the U.S. Navy Fleet
Numerical Meteorology and

Oceanography Center, Monterey, CA)

[^1]: Errors given for the 96 and 120 h periods are averages over the
    four-year period 2001-4.