A cold front off shore this morning will pass through the region this afternoon bringing gusty winds, rain and a drastic drop in temperatures. The limiting factor with this storm will be moisture and thus most of the precipitation will be along and west of the Cascades in southern Oregon, in particular at the coast and higher elevations. The coast has a slight chance for isolated thunderstorms this afternoon with the potential for small hail to form. Inland areas could see graupel the next few days as well, especially for higher elevations. Elevations above 2,500 feet by tomorrow morning will be switching from rain to snow! Snow levels drop to 2,500 feet tonight and while snow will not accumulate at first  because roads and soils are still warm, the Cascade passes could see some snow-covered and slick roads by tomorrow morning as temperatures plummet tonight.  Starting this evening through Thursday we could see the following snow totals:

Cascade Passes and Siskiyou Summit: 2″-5″

Kalmiopsis including the newly re-opened Bear Camp Road: 8″-16″

Oregon Cascades: 4″-8″

Siskiyou County and east of the Cascades will see lesser totals but could potentially be up to 3 inches.

With gusty winds today and falling snow tonight the potential for wintery travel will be present, especially by tomorrow morning after snow has had a chance to stick to the roads. While east of the Cascades will see isolated to scattered showers, starting tonight most will be in the form of snow; and winds will be the main concern as gusts up to 45 to 55 mph are possible and a Wind Advisory has been issued from noon until 8 tonight for that area.

A cold air mass will settle over the Pacific Northwest through the remainder of the work week with Wednesday being the coldest day. Temperatures tomorrow morning will be near record lows; well below freezing on the east side could cause pipes to burst thus precautions should be made to protect your pipes. Some localized areas of the west side valleys of southern Oregon could see a frosty start to the day, with the highest threat for frost in the Shasta Valley where a Freeze Watch is in effect late tonight through early tomorrow morning.

Our Memorial Day weekend will be more mild (seasonable) in terms of temperatures but another disturbance will bring another chance for showers late weekend.

I’ll have the latest road reports tomorrow morning and will bring you the all the details on this storm, follow me on Facebook for more. Thanks for logging on and have a great Tuesday!

Meteorologist Megan Parry

Severe weather has again moved through the heart of our country, bringing devastation to another town near Oklahoma City, OK. This time, it was the densely populated suburb of Moore, a city that has seen weather of this nature before. In 1999 an EF-5 tornado struck the town, with wind speeds in excess of 200mph. The leveled buildings and toppled cars this time around is suggesting a tornado of similar strength.

Severe weather isn’t in the forecast here, but winter weather is! A drastic change will begin late this evening as a cut-off low moves in from the Northwest. This storm system is going to drop temperatures significantly, along with snow levels. The primary concerns are heavy rain and snow potential in the higher elevations.

Afternoon highs Tuesday will be anywhere from 15-20 degrees cooler than Monday, but temperatures are going to drop even more so into Wednesday. Afternoon temperatures will only be in the 50’s midweek across much of the viewing area. The late and unseasonably cold weather will support snowfall as snow levels drop to 2,500’ Tuesday night. During times of heavier precipitation, this could be even lower.

Because ground temperatures are warmer, snow accumulation will be difficult in the lower elevations. For this reason, just a slushy coating is expected near 2,500’. However, in higher terrain above 4,000’, snow has a likely chance of falling and sticking, especially where snow is already on the ground. Here is how snow totals are looking over the course of the week:

8-16” Kalmiopsis
2-6” W. Side
4-8” S. Cascades
2-3” Klamath Basin

Winds are going to increase in the higher elevations and also on the East Side. Gusts will be around 35-45mph, and strongest near Summer Lake and Silver Lake.

Unsettled weather will last through Thursday evening as several waves of energy swirl around this strong and deep area of low pressure. Moisture will be in high amounts, so measurable rain is forecast for coastal sections. Stay with NewsWatch12 for updates.

CNN contributed to this report. ABC News has continuing livestream coverage.

[UPDATE: 6:30 p.m. Monday] MOORE, Okla. — At least 51 are dead after a massive tornado struck the Oklahoma City area. Eyewitnesses report schools demolished and children trapped. More than 38,000 are reported without power.

[PREVIOUS STORY] A second round of severe weather has begun developing across the Central Plains. A massive tornado tore through a densely populated Moore, Oklahoma on Monday afternoon.

The tornado touched the ground in Duncan and moved east, northeast into Moore, south of Oklahoma City. Monday’s tornado is estimated to be about two-miles wide. The destruction is extensive with countless homes and businesses flattened. Meteorologists from the area are reporting the damage to be the worse they have ever seen.

Moore experienced a devastating tornado about a decade ago, in May of 1999. The tornado was ranked an EF-5 on the Enhanced Fujita Scale, the strongest a tornado can be in meteorological terms. It is likely that Monday’s twister which passed through the town again had wind speeds of the same nature, as the damage appears to be worse than the horrifying past twister.

At least two people have been killed in this severe weather event. More than 171,000 people could have been in the path of the storm.

SHAWNEE, OK. – The ingredients mixed well Sunday across the country’s heartland, where severe thunderstorms produced as many as 29 tornadoes throughout the course of the day. Mother Nature proved her true potential to many who are now searching through rubble to salvage anything they can.

One of the strongest cells passed just south of Oklahoma City, moving northeast into Shawnee, OK where extensive damage is being reported. Homes and businesses were flattened, semi-trucks blown over, and vehicles thrown considerable distances.

NWS meteorologists are spending the day doing damage assessments to determine the strength of the tornadoes. Among the records are 312 severe wind reports, where winds were in excess of 56mph, and 197 hail reports. The preliminary data is suggesting the Shawnee, OK tornado was an EF-4, meaning wind speeds were between 166mph-200mph. It’s possible this could upgrade to an EF-5.

The tornado threat will continue Monday across the Central Plains, as instability is expected to be nearly just as high.

A ridge and thermal trough will bring summer-like temperatures this afternoon, abundant sunshine, and even the Chetco Effect at the coast warming Brookings up more than the rest of the coast. This warm-up is short lived however as a upper low will become cut-off from the jetstream and take hold of the Pacific Northwest weather through at least Friday. The limiting factor of this system will be moisture, so expecting the chance for rain through at least early Friday but it won’t rain all every days and most areas may just see lighter showers with a mix of sunshine. What will bring the rain each day will be disturbances wrapping around the low, the timing of these are difficult to pinpoint but will be with us as long the low is present.

The big story with this storm will be the potential for snow levels to drop to 2,500 feet by Wednesday morning! This includes the Cascade passes and potentially down to Sexton Summit in heavier showers. Since we’ve been on the warm side and with higher sun angles, any snow that accumulates shouldn’t linger more than a few hours. Starting Tuesday night be prepared for winter travel if you’re headed over the passes and this may be the story at times through Friday morning.

As of now Memorial Day weekend is looking drier and warmer with seasonable temperatures, mid-70s for west side valleys and mid to upper-60s east of the Cascades. When it comes to cut-off lows though, things can change quickly since it won’t be following the westerlies it will linger until it is caught back up by the jetstream. Based on weather models at this time I’m giving it four days to head east and return more sunshine by Saturday.

Follow me on Facebook for more weather updates and road reports later this week. Thanks for logging on and have a great Monday!

Meteorologist Megan Parry

I first want to mention the severe weather across the Midwest. Very strong thunderstorms along with, as of 8 p.m. Sunday — 26 tornadoes, have touched down this afternoon and evening across portions of Oklahoma, Kansas and Nebraska. Just near Oklahoma City, and specifically Shawnee, a massive and strong tornado has flattened homes and caused extensive damage. Thoughts and prayers are with those who have lost their homes, vehicles, businesses, and more. As of now one death has been reported, however I’m sure the death toll will rise. Unfortunately, more severe weather is expected into tomorrow.

Fortunately, the NW is not in a similar situation! In fact, high pressure is bringing just the opposite. Afternoon highs were considerably warmer for most areas compared to Saturday. The same scenario is expected into Monday. Temperatures will again warm an additional ten degrees. Inland areas will have afternoon highs in the 80′s, and the forecast high for Happy Camp is in the low 90′s! I’m calling for 70′s on the East Side.

A sudden change will occur by Tuesday as a very strong and deep area of low pressure, a cut-off low we call this, moves in from the Northwest. This system is going to linger across the region through the entire remainder of the week. Heavy and measurable rain will fall along the Coast. This will move further inland throughout the course of Tuesday, and finally the East Side by Wednesday. The major concern is going to be temperatures, which will drop to well below average for the end of May. This very cold air mass is going to allow for snow levels to plummet as well. By Wednesday morning levels will be around 2,500′ and potentially lower during times of heavy precipitation. This could be a problem for passes and the morning commute. Because ground levels are warm any snow that does fall in lower elevations will not stick very long. However, the higher terrain, especially areas where snow is still lingering, will see that snow hold together much longer.

More details will come as the storm nears, and certainty among the forecast increases.

Have a great week!

Meteorologist Alyssa Caroprese

A weak cold front swept through the state this afternoon. Light and widespread showers developed as a result, but precipitation totals did not amount to much. Showers will gradually diminish from west to east towards midnight, and following this skies will begin to clear.

By Sunday, a high pressure ridge will begin to set up across the Eastern Pacific and this will make for sunny and warm conditions. Temperatures should jump ten degrees into the second half of the weekend. By Monday, we’ll see another increase in afternoon highs, again another ten degrees. This will be the last day of spring, or more like summer, weather. A strong storm is on the horizon.

Tuesday clouds will begin increasing ahead of a strong and deep cutoff low. This system will bring a chance for precipitation to the entire viewing area through the remainder of the week. The biggest change will be temperatures. The air mass moving into the NW with this low pressure system will bring unseasonably cool conditions. A 15-20 degree temperature drop will occur Monday through Wednesday. With very cold air aloft, snow may even fall in the higher elevations. This is something that will have to be monitored closely into the next several days.

Enjoy the rest of the weekend!

Meteorologist Alyssa Caroprese

If you have outdoor plans this weekend, the weather shouldn’t be making too much of an impact. In fact, it should be fairly nice. A weak shortwave will move through Oregon Saturday, bringing very light and isolated showers first to the Coast beginning earlier in the day. This system will progress further inland throughout the course of the day, bringing a slight chance for a sprinkle in the Valley and an occasional shower to the mountains & Northern Siskiyou County. Most of the Valley should see mostly cloudy and dry conditions Saturday.

By Sunday evening weak ridging will build in and make for partly to mostly sunny conditions across the viewing area. Temperatures will stay on the cooler side through next week, but these temperatures only feel cooler because we’ve had such a mild spring so far. They are actually rather seasonable!

Sunny skies continue into Monday before clouds begin increasing ahead of our next storm system. This stronger and deeper low is similar to the one we had several weeks ago which sparked the thunderstorms across the area. At this point, the main energy remains to our North, over Northern Oregon and Washington State. However, this could change in the coming days and it is something we will have to monitor.

For now, TGIF! Enjoy the weekend!

Meteorologist Alyssa Caroprese

What is a sneaker wave?
MaryAnn McCoy
Grants Pass

A sneaker wave is a large wave that typically appears out of nowhere along coastal sections. They form from very strong storms that develop along the eastern side of Asia. They can grow nearly as large as hurricanes but are not tropical systems and rather strong, deep areas of low pressure.

Sneaker waves often catch swimmers, beach goers, and bystanders off guard. For this reason, the NWS will issue warnings or watches in advance to advise the public to keep away from the water. The rule of thumb is to never turn your back on the water, due to the history and hazards associated with these waves.

“Why do low pressure and high pressure rotate in opposite directions?”
Dave Wilson
Central Point

Because the sun heats the earth’s surface unevenly it causes air to expand and contract at different places across the globe. As a result, air pressure is different at all points on the earth. It’s these pressure differences that cause the wind to blow. Wind is created as air moves from high to low pressure.

High Pressure is seen on a weather map as a Blue Capital “H”. Near high pressure, the wind is usually light and circulates clockwise (in the Northern Hemisphere) away from the high. Because the air is leaving the high pressure area, air from above comes down to replace the air that left. This sinking air keeps the skies mostly clear and free from clouds that could develop into showers or thunderstorms. High pressure is usually associated
with nice weather.

Low Pressure is seen on a weather map as a Red Capital “L”. Since the pressure is low, air needs to fill it in, so it moves toward the low, but around it counterclockwise (in the northern hemisphere) at the same time. Often the winds can be quite strong around low pressure. Because the air is piling up at the low, some of the air is forced up. This rising air often becomes clouds and even produces rain and snow if cold enough. If the atmosphere is “unstable” then the rising air can become thunderstorms. Low pressure is associated with stormy weather.

Friction is a force that acts to slow down the movement of an object. Ice has a very low amount of friction, so walking across it is very slick, but sandpaper has a high friction and you could get good traction walking across
sandpaper.

Since the Earth is constantly rotating, the wind “turns” as the world turns. This is known as the Coriolis force. But there is friction at the surface. Friction not only slows the speed of the wind, but it also changes
the effect of the spin of the Earth.