BORTAS A 2010 Forecast
Issued Thursday, July 29th, 2010 AM
Valid for Today, Tonight and Friday with an outlook for Saturday.
Quick Overview: Low potential for LRT anthropogenic aerosols today. Moderate potential tonight. Low
to moderate potential Friday.
Low to moderate potential for biomass burning aerosols today and tonight. High potential for biomass
burning Friday.
Synopsis and Discussion:
Fires continue over northern Saskatchewan and the southeastern portion of the NWT north of Lake
Athabasca. An upper low was analyzed east of James bay at 00 UTC with a trough extending
southwestward. A complex surface low resides over northern Quebec and Labrador. By Friday
evening, the lows will move off the Labrador coast. The upper trough will be just west of Nova Scotia. A
surface trough will cross Halifax tonight.
As the upper trough moves eastward, the 500 hPa flow straightens out to provide streamlines directly
from the fire region to Atlantic Canada. The last run of the GEOS-5 (28th at 00 UTC) has a marked boreal
biomass plume between ~4 and 6 km over Halifax beginning Friday afternoon.
GEM-MACH has the main anthropogenic plume over New Brunswick today. The potential for
anthropogenic aerosols over Halifax increases this evening as the plume shifts southward, but the plume
weakens overnight and Friday. Rain in the forecast today and this evening is likely to wash out a
significant portion of the aerosols.
Today: Periods of rain with risk of thundershowers. Patchy fog. Low potential for anthropogenic
aerosols. Low to moderate potential for boreal biomass aerosols below ~ 2 km.
Tonight: Rain ending this evening then cloudy with a chance of showers. Fog patches. Moderate
potential for anthropogenic aerosols. Low potential for boreal biomass.
Friday: Cloudy with sunny periods. Fog patches retreating to the coast. Low to moderate potential for
anthropogenic aerosols. High potential for boreal biomass aerosols between ~4-6 km in the afternoon.
Outlook for Saturday: A mix of sun and cloud. Low potential for LRT anthropogenic aerosols. High
potential for boreal biomass aerosols.
Prepared by: Doug Steeves Contact: 426-1717