Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 161210

Area Forecast Discussion
National Weather Service Spokane WA
510 AM PDT Tue Jul 16 2019

More cool and breezy weather expected today. A few low land
light showers are possible with a chance of showers and
thunderstorms in the northern mountains this afternoon. Widespread
windy conditions are likely Wednesday into Thursday. Spotty
showers will continue in the northern mountains through the work
week. Hot and dry weather looks to return by Sunday into early
next week.


Today through Wednesday night: Coolish and breezy summer
conditions will persist through mid week as pair of upper
low pressure systems brush the Inland NW. The current system is
a weak upper level trough with a couple minor waves in the flow.
Water vapor satellite shows one wave just north of the Idaho
Panhandle which is assisting to keep plenty of mid level moisture
across the region and the second is over western Washington. With
pwats near an inch and weak lift, will continue to experience
spotty showers and sprinkles from the Columbia Basin to north
Idaho this morning. By this afternoon, surface based instability
increases especially across northeast Washington into north Idaho
where cape values rise to 250-400 J/kg with little in the way of a
cap. The 700-500mb winds will remain light westerly, less then 15
mph which will reflect slow storm motion. This supports the idea
of slow moving showers and thunderstorms with the potential for
heavy downpours across the northern mountains this afternoon and
early evening. Daytime highs will be subdued by cloud cover again
today, and will run about 5 degrees below normal. Meanwhile gap
winds will increase late this afternoon and evening with gusty
westerly winds developing from the Cascade valleys into the
western Basin with brief gusts to 25 mph. The threat of convection
and winds decrease overnight as the weak trough departs.

The next system to watch will arrive from the Gulf of Alaska
aided by a strong zonal jet stream. A cold front will push across
the region on Wednesday with mainly mountain showers. Instability
looks too weak to support thunder. The main impact will be the
windy conditions that develop across central and eastern
Washington by Wednesday afternoon. Anticipate westerly winds with
sustained winds of 15-20 mph and gusts 30-35 mph Wednesday
afternoon and evening. Although temperatures remain cool and
humidities elevated, the winds may raise concerns for fire weather
impacts, while outdoor enthusiasts especially boaters may be
effected by these windy conditions. /rfox.


***Stronger Gusty winds with Low Relative Humidity will elevate
Fire Concerns.***

A broad area of low pressure continues into Thursday with
the Inland Northwest  states under strong westerly flow aloft.
Climatological comparisons for winds aloft shows an anomalously
strong jet with 140kt at 250mb. That much wind won`t translate
to the surface obviously but some of that energy will. Whatever
weak inversions formed overnight will quickly evaporate and winds
should start up again by mid-morning increasing into the afternoon
hours until late evening.

*Wind gust potential to 35 or 40 mph will be possible east slopes
of the Cascades, Central Basin and Palouse. Winds will extend into
the Spokane area as well.

Potential for isolated thunderstorms will be limited to near the
Canadian border Thursday with showers near the Cascades into
Friday morning.

These persistent day and evening winds will certainly elevate fire
concerns with abundant dry grassy fuels ready to burn. Boaters may
need to take caution as well on exposed lakes. Relative humidity
values will be near critical levels and the winds Thursday. Friday
will still have some locally breezy conditions in the Cascade
gaps and will be the coolest day of the week with temperatures
well below seasonal normals in the 70s to lower 80s.

After the mid-week, windy weather the weekend starts a warming trend
with much less wind as the low pressure system moves out of the
region and high pressure takes its place. By Monday, Summer-like
weather moves back in with temperatures in the upper 80s to upper
90s. TC


12Z TAFS: A weak short wave pulse from a broad trough influencing
the region moves northeast over the region this morning and
carries the threat of showers over the eastern TAF sites. This
threat will continue through the morning and push northeast over
the mountains of northeastern WA and the northern ID Panhandle.
There also remains the chance of an isolated embedded thunderstorm
developing as the wave continues moving northeast across the
region. Confidence remains low if this condition continues past
late this afternoon. VFR conditions are still expected over the
TAF sites, but brief MVFR cigs are still possible in some areas
of the Purcell Trench near KSFF- KCOE and across the L-C Valley
near KPUW-KLWS this morning between 12Z-18Z as some lower clouds
spread in with the showers. /aky


Spokane        77  57  76  55  78  48 /  20   0   0  10   0   0
Coeur d`Alene  76  56  75  55  76  48 /  20   0  10  10  10   0
Pullman        76  53  75  54  76  46 /  10   0   0   0   0   0
Lewiston       84  59  83  61  84  56 /  10   0   0   0   0   0
Colville       81  49  80  45  82  40 /  20  10  20  10  10   0
Sandpoint      75  53  72  52  73  45 /  30  10  20  20  20  10
Kellogg        75  57  72  58  72  51 /  20   0   0  10  10   0
Moses Lake     85  58  82  56  83  50 /  10   0   0   0   0   0
Wenatchee      83  61  78  60  78  55 /  10   0   0   0   0   0
Omak           82  59  80  54  81  50 /  20   0   0   0   0   0




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