TEPHI/ HODO EXERCISE

Td not plotted – only T and Tw Abundant low level moisture Fog and stratus will take some of the energy that would have otherwise heated the ground up to the Tc convective temperature Cold aloft Huge amount of LI Lots of PI as well Huge amounts of CAPE Severe convection BOOM Very unstable with July datm htg Stratus Overnight cooling - Fog

Huge amount of LI Lots of PI as well Huge amounts of CAPE Severe convection

Lots of weather along these warm fronts! Heavy snow mainly in the form of small crystals Little snow – big snow Overcast nimbostratus Veering in CCA implies warming even without the Doppler – could just be Ekman Anabatic Warm Front Anabatic Warm Front

Some mid level moisture. AC. Theta w increases considerably but no clear frontal zone. All air masses fairly dry. Some mid level moisture. AC. Post cold frontal with high building in across NFLD No pcpn. Subsidence inversion Overnight cooling – Ice Fog possible Tf

Veering just above the front … enough for a katabatic front… PBL well mixed judging only by T trace. Unstbl in PBL with turbulent SC aligned in gusty NWLY flow. Note pcpn forming at -10 to -15. This creates large dendritic snowflakes where the vapour pressure over ice is a maximum. The snow is still falling heavily. Subsidence inversion

Subsidence inversion Overnight cooling – Ice Fog possible Tf

Note pcpn forming at -10 to -15 Note pcpn forming at -10 to -15. This creates large dendritic aloft even though the Arctic airmass is in effect at the ground level. The snow is still falling but sublimating away in the dry areas below. Overnight cooling – Arctic inversion 18Z

Datm htg will not be a factor for the onshore flow in March. Low level flow off the Gulf of St Lawrence. Moderating effect on temperature and moisture source for Td. Unstable below subsidence inversion especially for saturation over ice. Datm htg will not be a factor for the onshore flow in March. Subsidence inversion

Very distinct warm front – nil shear above the frontal surface. Two distinct air masses – one front. Overcast nimbostratus. Rain at ground. About 30 mb required to melt the snowflakes.

Very distinct warm front. Two distinct air masses – one front. Overcast altostratus. Extensive virga from AS Probable dry CCB Virga

Very distinct warm fronts – Three distinct air masses – two fronts. Overcast nimbostratus. Rain at ground. About 30 mb required to melt the snowflakes. No icing in cloud. CCB

AFL aloft. Melting snow to all rain. Large and deep layer of below freezing temperatures. All rain transformed ti IP. IP at ground mixed with the smallest melted IP – small rain drops. Warm front moving NNW at 40 kts… fast. The surface front does not have to be moving at the speed. It is only the front at the level of the thermal wind – wind shear.

Cloud Amount Analysis For deep cloud layers: Average cloud amounts inferred from dewpoint depressions are: 0 - 2oC suggests overcast 2 - 4oC suggests broken 4 - 6oC suggests scattered increase the ranges below -12oC (1oC/ 1000) for thin layers allow greater spread

Cloud Amount Analysis For deep cloud layers: Average cloud amounts inferred from dewpoint depressions are: 0 - 2oC suggests overcast 2 - 4oC suggests broken 4 - 6oC suggests scattered increase the ranges below -12oC (1oC/ 1000) for thin layers allow greater spread