Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Spokane Washington
223 am PDT Thursday Jul 30 2015
a dry and hot weather pattern will persist through the weekend.
High temperatures in the 90s to near 105 will be common through
the weekend. A gradual cooling trend will begin early next week. A
more dramatic change to the hot pattern may occur by the middle of
next week with an increasing threat of thunderstorms each day from
Monday through Wednesday.
today through friday: hot and dry weather with mostly clear skies will
continue as high pressure continues across the inland northwest.
The thermally induced surface trough will waiver over the
Cascades today, helping to keep winds light as temperatures rise.
After a warm day Wednesday, expect temperatures about 4 to 7
degrees higher than yesterday. This will lead to daytime highs in
the 90s with a few triple digits in the lc valley, deep basin and
a few Cascade valleys. The heat will continue into Friday. After
mild temperatures overnight, Friday looks to be the warmest day as
temperatures climb a few degrees higher, with more triple digits
readings and even possible near record temperatures in a handful
of locales. The thermal trough will push east of the Cascades
Friday, helping to enhance more of a westerly breeze of 10 to 15
mph from the Cascades into the Columbia Basin by Friday afternoon.
Friday night through Sunday...hot and dry conditions with mainly
clear skies are confidently expected during this period with good
model agreement depicting the forecast area sitting under the
northwest shoulder of the 4 corners high with a strong thermal
trough established over the Columbia Basin. The heat and
correspondingly dry conditions may be aggravated from a fire
weather standpoint by locally breezy late afternoon and early
evening conditions near the Cascade gaps during this period.
Otherwise there is little to elaborate on.
Sunday night through Wednesday...latest models suggest a more
interesting and potentially dangerous weather pattern will
develop by the middle of next week. By Monday all model guidance
is in agreement in dropping a new Pacific trough out of the Gulf
of Alaska promoting an increasingly southerly flow aloft over the
region. This will probably result in a creep of monsoonal
moisture from the south at least clipping the southeastern reaches
of the forecast area for Monday afternoon and Tuesday...bringing
an increased threat of thunderstorms across the eastern part of
the forecast area. Wednesday afternoon may be the day to watch but
Tuesday could be quite active as well. The latest GFS pushes a
noticeably strong short wave into the forecast area during the
day Wednesday with a slight negative tilt on the latest run. The
latest ec model is significantly weaker but also wildly
inconsistent with it's previous run...which honed closer to the
latest (and prior) GFS solution.
Previous case histories suggest ugly things tend to happen when a
negatively tilted trough with a deep moisture field flushes out a
hot and dry air mass during the month of August. While confidence
is low due to the model differences and the far extended time
frame...it is probably prudent to begin focusing on the
possibility of an active and even severe weather episode by the
middle of next week. Timing will play a large part in how this
evolves...a less threatening overnight short wave transit or a
potentially more apocalyptic afternoon arrival. Too early to nail
down at this time. /Fugazzi
06z tafs: mainly clear skies and light, terrain driven winds are
expected over eastern Washington and north Idaho through 06z
Preliminary point temps/pops...
Spokane 94 64 98 64 97 66 / 0 0 0 0 0 0
Coeur D'Alene 93 59 96 58 97 61 / 0 0 0 0 0 0
Pullman 94 57 98 56 96 58 / 0 0 0 0 0 0
Lewiston 101 68 105 69 104 69 / 0 0 0 0 10 10
Colville 96 57 100 57 98 59 / 0 0 0 0 0 0
Sandpoint 89 52 93 52 93 54 / 0 0 0 0 0 0
Kellogg 92 57 96 57 96 58 / 0 0 0 0 0 0
Moses Lake 99 62 102 63 101 66 / 0 0 0 0 0 0
Wenatchee 100 70 103 68 100 72 / 0 0 0 0 0 0
Omak 99 62 102 62 101 65 / 0 0 0 0 0 0