BORTAS A 2010-08

BORTAS A (2010)
BORTAS Meteorological and Air Quality Forecast for Halifax region (Boundary
Layer and Free Troposphere)
Issued: Wednesday, August 4, 2010
Issued by: David Waugh
Valid Today, Tonight and Thursday with an outlook for Friday
Quick overview: Low - Moderate potential influence from boreal biomass
through period.
Low potential influence from anthropogenic LRT today. Increasing
potential overnight and Thursday.
Synopsis/Synoptic Discussion:
Fires continue across regions of northern Saskatchewan extending to Great Slave
Lake, also over Washington, Oregon, the interior of British Columbia south of Prince
George as well as scattered fires over northwestern BC/southern Yukon, eastern
Alaska. Ray Hoff’s indicates, in his smog blog, imagery of fires in Siberia and
discusses two major pyro-Convective Cb events there.
Complex upper trough over Hudson Bay-James Bay will support development of
surface low over Quebec tonight and Thursday. Mid level flow supports transport of
some smoke from northern Canadian fires toward Maritimes. Warm front pushing
across NS today in SWly flow through low and mid levels. Bands of mid cloud
indicated on the GEM to be over NS much of period with coastal fog patches. Surface
trough and cold front forecast to move over NS Friday bringing more precipitation
ahead of it. Low level flow to become westerly behind the front on Friday.
Current run of the GEOS-5 (3rd at 12 UTC) shows low to moderate levels of CO from
boreal biomass below ~6 km today and below ~2-3 km on Thursday. The model
shows a break in the boreal biomass CO Thursday evening. GEM-MACH indicates
main anthropogenic plume to be over southern NB and western NS later Thursday.
Cloudy. Showers and chance of a thundershower ending late this afternoon. Coastal
fog and drizzle. Some boreal biomass CO below ~6 km. Low potential for
anthropogenic aerosols due to precipitation.
Cloudy. Chance of an evening shower. Fog spreading inland. Some boreal biomass
CO predicted below ~4 km. Low to moderate potential of anthropogenic aerosols.
Cloudy with sunny periods and scattered late afternoon and evening showers with risk
of a thundershower. Coastal fog. Some boreal biomass CO predicted below ~2-3 km.
Increasing potential for LRT of anthropogenic aerosols in the afternoon.
Outlook for Friday: Cloudy with sunny periods and scattered daytime showers. Low
to Moderate potential for boreal biomass in low to mid levels. No significant LRT of
anthropogenic aerosols.
Contact: David Waugh
Contact number: 426-9136