Drought, Dry, Storm, Thunderstorms, Trough, Windy

Drought, Dry, Storm, Thunderstorms, Trough, Windy 0

 0

I wish I could have wrote this sooner, but time and work got the best of me. In any case, it appears the last storm we’ll see for a while will swing through northern California Wednesday afternoon into the evening, with a quick burst of rain and mountain snow as a narrow cold front slides through. This front will be driven through the area due to a trough rapidly diving into the Pacific Northwest & Great Basin. It isn’t a full-blown inside-slider, but it is taking a much more inland track than many of the storms we’ve seen this season. Usually these more interior-based systems are cooler than storms that have more offshore land to venture over, and this trough will indeed be a bit cooler than the last few, but nothing extraordinarily cold.

NAM’s forecast 500mb wind and heights, valid at 4pm Wednesday. The trough axis can be noted clearly dipping into northern California with the dip in the heights.

The front looks like it’ll bring precipitation to areas north of Chico between 8 – 11am, and between 11 and 1pm from Chico to Yuba City. In the Sacramento/I-80 & Highway 50 corridor, 1pm to 4pm looks to be the timeframe for precipitation to begin and start winding down. The frontal band looks like it’ll be pretty narrow – perhaps just 50 – 75 miles wide at best. Parts of the central valley may get rain shadowed as the westerly flow of the moisture plume associated with the front gets blocked partially by the coastal mountains. Lift up the west slope and banking against the foothills should allow the east side of the valley to get in on the action, but parts of the western valley adjacent to the coastal mountains may little to locally no precipitation. Slightly better moisture is able to make it into the Sacramento/I-80 corridor through the delta, and may allow accumulating precipitation to fall through most of the I-80 and Highway 50 corridor.

Precipitation will be mostly light to moderate in the valley, with moderate to locally heavy precipitation in parts of the foothills and especially further up the hill where the upslope flow wrings more liquid out. Snow levels look like they’ll begin around 5000ft, but lower quickly to around 3000 – 4000ft along the back edge of the precipitation band/cold front. Snow will be heavy at times over the passes, and it appears a quick 6 – 12″ is possible above 5000ft over the course of 4 – 8 hours!

4km NAM’s forecast 700mb vertical velocities, indicating rapid vertical motion (warm colors) up the west slope, indicating good lift/upslope flow.

In the valley, if clearing occurs in the morning ahead of the front in the central and southern parts, enough heating may occur to allow for some convective development along, ahead, and behind the front. Currently looks like 100 – 400 j/kg of CAPE forecast along the front, which combined with any lower-level buoyancy (a sun-warmed surface), may support the development of deeper convection or thunderstorms… mainly from Chico southward, and much more likely along the east side of the valley up into the foothills & mountains, where moisture & lift is maximized. Strong mid-level jet traveling along the base of the trough will aid any thunderstorms that develop. Shear is decent… but it doesn’t currently appear like a favorable setup for discrete/isolated convection to develop, rather more linear. 40 – 50kt 850mb winds jetting overhead Wednesday could get tapped into by any heavier precipitation and especially any thunderstorms, and could drag down some gusts upwards of 30 – 40mph if thunderstorm development were to occur, but at the moment no real severe threat appears likely.

The east side of the valley may pick up up to around a quarter to three tenths of an inch, with a tenth or so further west, and even less along the west side of the central and northern valley. A quarter to half inch looks like a good bet in the foothills, with around the same to perhaps three-quarters of an inch of liquid precipitation equivalent in the highest elevations and where upsloping is maxed out.

Riding rapidly takes over behind the system, creating a tight pressure gradient as a deep surface low develops in the Rockies. Breezy to gusty winds will become prevalent across a good chunk of northern California from Wednesday night through Thursday… lingering into Friday, mainly in the mountains. Other than that, the pattern looks like it may stay quite through the end of the year… possibly into January. Definitely not what we need if we’re trying to bust out of our historic drought.

Three Day Forecast.......

Three Day Forecast.......

https://www.facebook.com/PNWeather

Tonight

Rain Mostly cloudy with rain likely. Lows around 45°F. Wind chill around 38°F. East wind to 16 MPH, gusting to 21 MPH. Chance of precipitation 90 percent. New precipitation amounts from one half to three quarters of an inch possible. 

Monday Dec 15

Rain Day: Cloudy with rain. Highs around 54°F. Windy, with a east southeast wind 14 to 20 MPH. Chance of precipitation 90 percent. New precipitation amounts from one half to three quarters of an inch possible. 

Showers Night: Mostly cloudy with showers. Lows around 43°F. East southeast wind to 8 MPH. Chance of precipitation 80 percent. New precipitation amounts up to one quarter inch possible.

Tuesday Dec 16

Showers Day: Mostly cloudy with showers likely. Highs around 57°F. East wind 4 to 9 MPH. Chance of precipitation 70 percent. New precipitation amounts up to one quarter inch possible.

Rain Night: Mostly cloudy with rain likely. Lows around 45°F. Southeast wind to 9 MPH. Chance of precipitation 70 percent. 

Wednesday Dec 17

Scattered Showers Day: Mostly cloudy with scattered showers. Highs around 57°F. West northwest wind to 7 MPH. Chance of precipitation 50 percent. 

Isolated Showers Night: Partly cloudy with isolated showers. Lows around 41°F. South wind to 6 MPH. Chance of precipitation 20 percent.

Sonoma coast get slammed by stormy weather . . .

Sonoma coast get slammed by stormy weather . . .

Posted: 12 Dec 2014 07:30 AM PST

Traveling anywhere in Sonoma County was risky during and after the storm so we stayed coast side. With the reports of 20' waves I couldn't stay cooped up in the house.

All of these photographs were taken at Duncan's Landing. Shooting here you and your camera can get drenched with one big wave.

I stood in the fierce wind and driving rain to get these shots.

Water runoff from the hills create new waterfalls everywhere along the coast.

Please be mindful of the slick wet roads. Watch for falling limbs, downed trees and flooded roads.

Strong Storm to Drench California, Raise Flooding Risk

Strong Storm to Drench California, Raise Flooding Risk

Powerful Storm to Impact the Bay Area this Week

NASA's 1st Orion Spacecraft Test Flight in Photos

NASA's 1st Orion Spacecraft Test Flight in Photos

'Painful' Cold to Stay Away Through Mid-December; Some Chilly Days on Tap

'Painful' Cold to Stay Away Through Mid-December; Some Chilly Days on Tap

Despite fears that the severe cold during November was a sign of what might ahead for December, much of the nation will be mild most days through at least the first half of the month.

According to Chief Meteorologist Paul Baker, "While the middle of November brought painful cold, temperatures will not drop off a cliff. There is no sign of winter getting worse any time soon."

Cold Records Shattered During November 2014

While there will be small pushes of cold air over the northern tier states during the first two weeks of December, these will tend to be brief.

The cold pushes from the northern Plains and the Upper Midwest to the Northeast will tend to last only a day or so. However, these can lead to minor rounds of wintry precipitation.

"We do not see any big arctic high pressures building southward out of Canada during the next two weeks or so," Baker said.

A fast west-to-east flow of air over the northern half of the nation will prevent smaller cold air masses from moving very far south for very long.

Most days from central Rockies to the central Plains, Ohio Valley and mid-Atlantic will bring near- to above-average temperatures for the first two weeks of December. Temperatures will average near normal in the South.

Temperatures farther north will fluctuate from day to day, but they will probably end up averaging close to the 30-year normal mark.

To put the temperature forecast in perspective, normal temperatures in the Northern states are about 10 degrees lower during early December, when compared to early November. The downward trend in normal temperatures does not bottom out until the middle of January.

The expected weather pattern will bring frequent storms to the Pacific coast. These storms will tend to weaken over the Rockies as they move swiftly to the Central and Eastern states.

We will be looking toward the western Pacific Ocean and the stratosphere for clues to when arctic air will return.

According to AccuWeather.com Long Range Expert Mark Paquette, "The track of Typhoon Hagupitand sudden warming in the stratosphere will be players as to how soon cold air returns and where the brunt of that cold air is directed."

"If Hagupit does not curve east of Asia or is delayed in doing so, the return to persistent frigid air in the U.S. may be delayed until Christmas or later."

Sudden major warming in the stratosphere often has a delayed and opposite effect in the lower part of the atmosphere. Stratospheric warming usually marks the beginning stage an arctic outbreak 14-21 days later.

"We suspect a stratospheric warming event may occur toward the middle of December," Paquette said.

There is the challenge of predicting which part of the Northern Hemisphere that the arctic air will move toward. A cold outbreak response to warming the the stratosphere is usually only directed to part of one continent.

In the meantime, people in the U.S. should not expect any widespread severe outbreaks of cold air through at least the middle of December and possibly later in the month.

The weather during the middle of December may get unusually warm over a large part of the nation, if Hagupit continues westward or stalls, instead of curving northeastward and away from the Asia mainland.