Tag: weather

Lack of widespread critical fire weather has kept fire starts down across much of the western US. Expect fire weather to become more critical today in OR/CA and spread eastward into ID/WY through late-week.

A cut-off upper level low off the coast of north CA will provide enough moisture and instability for scattered dry thunderstorms over high elevations. Very dry surface conditions combined with hot temperatures will make fuels very receptive to dry lightning. Tues, the low will drift southward along the coast, but lose ample moisture to provide widespread storms, however a few isolated storms are possible in central/north CA through Tues evening.

A more potent upper level trough will enter dig into the Pacific Northwest Tues, and begin to eject over the Northern Rockies on Wed. In advance of this trough, surface pressure falls are expected across central OR/WY creating breezy westerly winds Tues and Wed. Combined with warm temperatures and dry conditions, fire suppression will become difficult. Higher moisture across extreme northern WA/ID/MT will develop scattered rain and wet thunderstorms over higher elevations bringing some relief mid-week, with a higher heavy rain threat for eastern MT late week.

Surface low pressure will begin to develop across the central Plains in response to the eastward movement of these upper level features. With high pressure over the Rockies and the western US, a strong pressure gradient will set up over WY and southern ID, and northern CO late week. This gradient will develop breezy conditions across these areas leading to critical fire weather. In addition, increased upper level moisture will provide ample conditions for scattered dry thunderstorms across the same areas, especially over higher terrain. Cooler conditions will develop across the northern Rockies late weekend. Meanwhile, warm and dry conditions will continue for CA and western/central OR/WA with isolated locations of gusty winds through the weekend.

Weather Highlights:

CA: Critical fire weather Monday due to dry lightning, warm temperatures and dry conditions. Threat will lessen and drift southward on Tues/Wed. Continued hot and dry through the period.

OR/WA: Scattered dry thunderstorms across higher elevations of southern OR Monday. Increasing winds Tues/Wed with critical fire weather conditions expected Wed. A few wet thunderstorms over higher terrain of extreme nrthern WA.

Southern ID/WY/northern CO: Very breezy conditions developing with warm temperatures and dry conditions continuing into the weekend. Scattered dry thunderstorms possible through the period over higher terrain. Critical fire weather expected Wed through Fri.
MT: Isolated dry thunderstorms possible Wed through Fri for southern MT, with wet thunderstorm chances across northern MT. Otherwise warm and dry through Thurs with heavy rain possible Fri across eastern MT.

Chip

Upper level low centered over OR/WA will continue to weaken over the next few days, before finally drifting northeast into Canada by the weekend. Conditions should gradually improve as thunderstorms become less numerous across the Pacific northwest on Thurs and even less on Fri. Moisture has become abundant around the low and with that, storm modes are expected to be mainly wet. Warm and dry conditions, with an isolated dry thunderstorm threat is possible Thurs across central MT. As the system drifts northeast across portions of MT on Fri, heavy rains are possible across E MT. Other scattered storms across the state are possible through Sat with mainly wet storm modes expected. No widespread critical fire conditions expected.

High pressure is already building into portions of CA, in the wake of the low. Dry, hot, but calm conditions have developed across much of CA and will continue to build north and eastward into OR/WA/NV/ID into the weekend. Temperatures will be above average for much of the western US Sat and Sun and into early next week. Some isolated pockets of breezy conditions are possible in central ID and MT, however, no widespread wind events are expected.

Long term, another upper level low makes an attempt to push onshore to OR/CA early next week. Not overly confident of any widespread thunderstorm activity at this time, though a few storms over higher terrain of north CA Mon and Tues are possible. There are hints at a larger pattern change for mid-week next week which will need to be watched for a possible wind event.

Weather Highlights:

MT: A few dry thunderstorms across portions of central MT Thurs with hot and dry conditions present. Heavy rain possible across eastern MT on Fri, otherwise scattered storms across much of the state. Warming and drying out Sun.

CA: Above average temperatures with dry conditions.

OR: Some showers and wet thunderstorms Thurs. A few lingering showers/storms north on Fri. Drying gradually from south to north, with increasing temperatures.

ID/WA: Scattered showers and wet thunderstorms through Sat, gradually waning and drying out from south to north through the period. Localized breezy conditions Sat/Sun.

WY: Becoming very warm Sat/Sun with breezy conditions.

Chip

Today meteorologist Chip Redmond sent us another fire weather outlook, for August 10 through 15.

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Upper level ridging across the western US has returned, resulting in warming temperatures and much less thunderstorm activity. Most fire activity has been limited to portions of OR/WA where breezy westerly winds have became prevalent along the Columbia Gorge and western slopes of the Cascades. Though these localized conditions are expected to wane, widespread critical fire weather conditions are expected to develop across the region late weekend and continue through much of next week.

A slow moving upper level low will develop on the west coast of CA/OR by Sunday evening. As it progress towards the coast, upper level moisture will begin pushing northward across much of the western US. This increase in moisture aloft and subsequent instability, will contribute to the development of afternoon thunderstorms. Surface moisture will remain minimal however, providing the ideal ingredients for dry thunderstorms. With very dry, drought-stricken surface fuels, widespread fire starts are possible. Though no widespread winds are forecasted, gusty winds can be expected around any thunderstorm activity.

The nearly stationary upper-level low will make this a prolonged event, with thunderstorm activity through the entire period. Storms will become prevalent in OR/CA on Sunday, and expanding north into WA on Monday/Tuesday, and eastward into ID/MT on Tuesday and Wednesday. By mid-week, enough upper level moisture may advect northward into CA/OR/ID/WA for some wet thunderstorms, however, dry thunderstorms will still be possible across much of the region. As the low shifts eastward by late-week, a break in the activity is expected across portions of OR/CA. However, warm and dry weather is expected to continue.

Weather Highlights:

OR/northern CA/southern ID: Critical fire weather through Wednesday. Daily dry thunderstorms with hot and dry surface conditions expected. Isolated wet thunderstorms by Tues/Wed.

WA: Critical fire weather Monday through Wednesday. Very hot across central portions of the state and with critically low RH Sun through Tues. Dry thunderstorms likely Mon and Tues with a few wet thunderstorms Wed.

Northern ID/western MT: Critical fire weather Monday through Wednesday. Hot and dry Mon and Tues with scattered dry thunderstorms. Increased chances of wet thunderstorms with slightly cooler temperatures Wed.

Chip

Today we have another article from Incident Meteorologist Chip Redmond.

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2014 August fire weather

Typical fire season for August is focused greatly on the western US and Pacific NW. This time of year a summer upper level ridge is usually prevalent across the western US. This leads to hot and dry conditions reaching into Canada. However, monsoonal rains creep northward into much of the inter-mountain west from Mexico bringing a break to fire season in much of Colorado, Arizona, California, Utah and other nearby states. These monsoonal rains are the wet season for many, and besides the winter snows, are a large source of water.

In the recent weeks, we have seen quite a bit of large fire activity in Washington, Oregon, and California. For this time of the year, it is fairly typical to expect hot spots in these regions. However, the size and vigor of these fires has been greatly magnified with already a record fire season (Carlton Complex). The main driver of these impressive fires has been the significant drought impacting the western US, which has been developing over the previous years. Despite some recent rains in many areas, especially inter-mountain West (thanks to seasonal monsoonal moisture), much of it has fallen to the east of the greatest Exceptional Drought. This drought has substantial impacts on both short and long term vegetation and fuel conditions. It has made the region very susceptible to very large fires with extreme fire behavior.

The big question is, will these conditions continue? Long-term it appears that they will. This persistent pattern is showing signs of weakening short term, but after this weekend, forecast models hint at more prolonged ridging much like we have had the previous weeks. A very active Western Pacific typhoon season is somewhat to blame. As systems move north, and eventually northeast past Japan, they amplify the large upper level ridge assisting in the continued hot and dry weather for the western US. With numerous typhoons still across the western Pacific, it appears this may continue to occur. Long-term models also suggest continued below normal rainfall and above normal temperatures for the next 1-3 months for the W US. There is some suggestion of El Nino development this fall which could bring some much needed relief to portions of southern California. However, should it develop, it would also suggest warmer than normal conditions across regions of Washington and Oregon.

It appears that it likely be a very long, and dragged out fire season for many in WA, OR, and CA.