Monday, February 23, 2015

Another Downslope Wind Event

It's another windy day along the northern end of the Wasatch Front. These strong easterly winds often occur when we have a low pressure set up in southern Utah with cold, stable air to our north east. Winds blow cyclonicly (counter-clockwise) around the low pressure center which pulls the cold stable air over the Wasatch Mountains. Since the air is cold and stable, when it passes over the mountains or funnels through the canyons it suddenly sinks and creates the strong winds.

MesoWest weather stations shows that the winds are strongest near the canyons. It was a blustery walk up to campus this morning.
University of Utah: Gusts nearly 50 mph at the Natural History Museum

Bountiful Bench

Hill Air Force Base and Weber Canyon

Brigham City
 The wind advisory is in affect until noon. Winds are expected to weaken in the late morning and early afternoon.
...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 AM MST THIS
 MORNING...
 
 * AFFECTED AREA...THE WASATCH FRONT FROM BRIGHAM CITY SOUTH
   THROUGH THE NORTHEASTERN PORTION OF THE SALT LAKE VALLEY.
 
 * WINDS...EAST WINDS 25 TO 35 MPH WITH GUSTS APPROACHING 60 MPH
   NEAR THE MOUTHS OF THE CANYONS.
 
 * TIMING...STRONG EASTERLY CANYON WINDS WILL CONTINUE THROUGH THIS
   MORNING. THESE WINDS WILL GRADUALLY DIMINISHING DURING THE LATE
   MORNING AND AFTERNOON HOURS.
 
 * IMPACTS...STRONG CROSSWINDS WILL IMPACT TRAVEL ALONG THE I-15
   AND US 89 CORRIDORS...ESPECIALLY THROUGH WEBER AND DAVIS
   COUNTIES...AND ALONG THE EAST SIDE BELT OF I-215 IN EASTERN SALT
   LAKE COUNTY. HIGH PROFILE AND LIGHT WEIGHT VEHICLES SHOULD USE
   EXTREME CAUTION WHILE TRAVELING THROUGH THIS AREA. WIND
   SENSITIVE OPERATIONS WILL BE AFFECTED.

While the ozone pollution isn't in the unhealthy range, it is interesting that ozone concentration has stayed flat during this wind event
It appears the background levels of ozone last throughout the night since the NOx titration of ozone is not occurring in the cities during the wind events.

No comments:

Post a Comment