NWP Forecast Guidance during Phet at Oman Meteorological Service - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 227

Table 2: Total precipitation and maximum wind speed recorded
during 1-5 June 2011

Station Name Rain amount (mm) Maximum wind speed (Kt)

Muscat Int. Airport 90 50

Mina Qaboos 162 40

Al Amerat 169 50

Samail 68 38

Rustaq 94 30

Ibra 41 55

Sur 156 65

Ras Al-Had 122 45

Masirah 177 85

Joba 60 48

model resolutions. High resolution model (HRM) which is hydrostatic is run
at 14 and 7 km resolution. On the other hand, the non-hydrostatic COSMO
model is run operationally at 7 km resolution. Recently, DGMAN upgraded its
computational resources and an HRM (2.8 km) is run in research mode. Both
models are initialized by the German global model GME which is running
operationally at 40 km resolution. The NWP models are initialized two times a
day at 00 and 12 UTC.
The objective of this study is to evaluate the performance of DGMAN's
NWP models during the tropical cyclone Phet period. Both models were re-
run to simulate the tropical cyclone Phet case in terms of cyclone track, wind
speed intensity and the precipitation amount. The forecast of both models with
different resolutions will be inter-compared with each other and with the
observations from surface synoptic stations and satellite images.

2.2 Preliminary Results

2.2.1 Cyclone Intensity
Figure 2 shows the observed (blue curve) maximum wind speed around the
Phet centre and estimated minimum surface pressure in the centre of the cyclone.
It also shows the forecasted maximum wind speed and minimum pressure
from different forecast runs for both HRM 14 km mode (brown curve) and
COSMO 7 km model (green curve). It can be seen that both models have
significantly underestimated the associated wind speed and significantly
overestimated the minimum surface pressure. This model behaviour is typically
associated with initial condition. Both models were initialized with German
global model which runs at 40 km resolution.

2.2.2 Cyclone Track
Figure 3 shows best track (black) of Phet and forecast tracks from different
models for different run time. Blue curve shows the track from HRM 14 km,