A classic intensifying warm front Case number 1 A classic intensifying warm front

Example 1-February 15 1990 Strong northeast outflow from high pressure centre. Dramatic temperature contrast across front 20 to 25 C.

Feb 15 1990 Stable waves along front. Doppler useful in assessing situation

Assessing the flow 1 The inbound easterlies in cold air In this 1.5 degree scan we see the inbound winds at low levels generally from the east. 60 km east of radar at a height of 1.7 km winds suddenly switch to outbound. This represents height of frontal surface. Echo free ring- Beam is seeing both inbound and outbound. High spectral width… data is rejected.

Assessing the flow 2 veering/backing of winds Near surface the zero line is north south implying easterly flow. Above surface we see zero line turning counter clockwise (backing) implying cold air advection. This front is intensifying or perhaps moving south.

The Low Level Jet Higher up (further out) we see inbound/ outbound max and min at outer rings (above 3 km) … the low level jet of around 36 m/s (70 plus knots) Typical feature in a warm frontal pattern.