By Dr. H. Kabelwa. What is WRF? Is the Weather Research and Forecasting Model Is a next-generation meso-scale numerical weather prediction system Is designed.

By Dr. H. Kabelwa

What is WRF?Is the Weather Research and Forecasting

ModelIs a next-generation meso-scale numerical

weather prediction system Is designed to serve both operational

forecasting and atmospheric research needs.It features multiple dynamical cores, Data assimilation system.

Domain of LVBWRF model is run over East African (bigger

domain) http://www.meteo.go.tz/pd/index.phpwith nested over Lake Victoria (small domain)http://196.46.109.62/NEST/The resolution of big domain is 15km while that of

small domain is 5km with ratio of 1:3WRF model is initialized from Global Forecast

System (GFS) data of 1200z.The model is run for 72 hrs starting from 1200z

every day.

Products Accessibility: EAD

Products Accessibility: EAD

Products Accessibility: LVB

WIND FLOW WIND AT 850hPa WIND AT 700hPa

WIND FLOW (cont..WIND AT 500hPa WIND AT 200hPa

RELATIVE HUMIDITYRH AT 850hPa RH AT 700hPa

WRF modelStrengthHigh resolution in space, 5km. High resolution in time, 3hr model outputs. 3-hour accumulated rainfallProducts: Wind profile, wind flow patterns,

Relative humidity, PW , etcMost of the time Captures the Lake features.

Comparison against Observations

24HRS RAINFALL ACCUMULATIONAS PER 07/11/2012 0600z

Satellite imagery of IR&VIS 07/11/2012 at 1015z

KIGOMA 10.6

KIBONDO 5.1

MWANZA 1.8UKIRIGURU 6.4

MUSOMA TRBUKOBA NIL

Observations

Both 850 and 700hPa wind flow patterns show convergence of North-easterly and Easterly winds over southern part of LVB

At 500hPa shows northward movement of convergence line

The moisture flux also shows some good agreement with areas of convergence

Precipitation forecast also give good signal which tiles with rainfall observation and satellite imagery

WRF modelWeaknessForecasting length - 48hrsVery sensitive to atmospheric conditions.No data assimilationWind gust cannot well capture

Event Location of the event is the western part

of the lake Victoria in the Tanzanian side.

Strong winds occurred in some of the villages in Rural Bukoba district. 30 knots was reported AT Bukoba station which is located a couple of tens of kilometers away.

Note: RFSC-Dar threshold for strong/severe wind is 20 knots.

Basing on the evidence of damage caused and reports from the villagers the case is suspected to be of a tornado.

Heavy precipitation did not Happen with only 10.1 mm Recorded at Bukoba station.

A way forwardMore research is required on physics and

paramaterization settings on the