Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 282124
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
224 PM PDT MON JUL 28 2014

.SYNOPSIS...
Hot temperatures and dry weather will continue through midweek.
Thunderstorms chances will increase during the latter portion of
the work week as monsoonal moisture overspreads the Inland
Northwest.

&&

.DISCUSSION...
.Tonight...Quiet and mild weather expected tonight due to strong
upper level ridge persisting over the region. Skies will
generally be clear as weak upper level disturbance currently over
extreme southeast Washington shifts into western Montana. Light
winds will prevail while relative humidity recoveries will be
quite poor over the mid-slopes and ridges. fx

Tuesday and Wednesday: The ridge will be in full control over the
Inland Northwest midweek, with continued hot temperatures
expected. Tuesday looks to be the hottest day of the week, as 850
mb temperatures are around 27 degrees Celsius. Little in the way
of cloud cover will get in the way, and not much breeze will be
present to make it feel a little "cooler." Expect whatever high
temperatures you experience to day (Monday) to go up another
couple of degrees, but then fall a few degrees for Wednesday
afternoon. This is in response to an increase in cloud cover as
monsoonal moisture overspreads eastern portions of the region.
Temperatures will likely begin the day on Wednesday on the warm
side, as mid-level cloud cover increases beginning Tuesday night
(and continues into Wednesday). A weak disturbance embedded in
the weak flow aloft may be enough to trigger some afternoon
showers and thunderstorms. Any precipitation would be more likely
over far eastern Washington into the Idaho Panhandle. This is not
a strong disturbance so widespread precipitation is not expected.
However, with the presence of thunderstorms, some new fire starts
are possible. But with increased moisture, hopefully any
thunderstorm would stay on the wet side. ty

Wednesday evening through Monday...Longwave ridge with axis
placement to the east over Central Montana remains in place due to
longwave trof/low remaining in place offshore and in the vicinity
of the Gulf of Alaska and a similar stagnant trof remaining over
northeast North America which essentially keeps the ridge from
moving anywhere. This persistent pattern allows for a persistent
hot forecast for temperatures and the potential for shortwave
disturbances of varying intensity to run up under or along the
west side of the ridge axis in a trajectory from the south or
southwest and possibly kick off thunderstorms through the
interval. As it stands now there is run to run model consistency
in passing such disturbances through the area in the form of a
negatively tilted trof rotating around the periphery of the Gulf
of Alaska low on Friday, otherwise there have been spottier
depictions in the models of smaller disturbances with limited
moisture/energy/lift coming up from the south. With this in mind
the pops and sky cover ramp up highest Friday and continue on into
through the remainder of the forecast with the idea the longwave
ridge axis should be further east once the Friday negatively
tilted trof passages which allows for a slightly better storm
track for disturbances to move up from the South/Southwest.
One thing very interesting to note is discussion about the 12Z
ECMWF bringing a closed wet circulation up from the south for the
weekend. If one rocks a 12Z ECMWF 500mb height, vorticity, and
QPF loop back and forth it does seem to look like this feature is
built upon bits of old remant moisture and energy ejected out of
tropical storm Hernan which is out if the East Pacific off the
coast of Mexico right now. /Pelatti

&&

.AVIATION...
18Z TAFS: High pressure ridge will deliver generally clear skies
and VFR conditions to all sites through 18z Tue. Main weather will
be associated with a weak disturbance tracking northeast through
SE Washington and the southern ID Panhandle. This could bring some
temporary mid level cigs to PUW and LWS and perhaps a sprinkle
through 21z...but most of that will occur east of these sites. fx

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        68  99  68  95  67  95 /   0   0   0  10  10  10
Coeur d`Alene  62  97  64  92  62  93 /   0   0   0  10  20  10
Pullman        58  97  60  93  61  92 /   0   0  10  20  20  10
Lewiston       71 103  72  99  68  99 /   0   0  10  20  20  10
Colville       59 100  60  98  59  97 /   0   0   0  10  10  10
Sandpoint      55  94  57  92  57  92 /   0   0   0  10  20  10
Kellogg        62  93  62  89  60  90 /   0   0   0  20  20  10
Moses Lake     65 104  67 101  67  99 /   0   0   0  10   0  10
Wenatchee      72 102  71 100  70 100 /   0   0   0   0  10  10
Omak           67 102  66 101  66 100 /   0   0   0   0   0  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory until 8 PM PDT Tuesday for Lewiston Area.

WA...Heat Advisory until 8 PM PDT Tuesday for Lower Garfield and
     Asotin Counties-Moses Lake Area-Upper Columbia Basin-
     Washington Palouse.

&&

$$




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