A very dynamic weather pattern will bring snow to the Central Rockies and High Plains as well as the Pacific Northwest; Severe Thunderstorms to the Southern Plains; and Heavy rain to the Mississippi, Arkansas and Red River Valleys as well as the lower elevations in Washington.   

Severe Weather in Southern Plains

A broad upper level low situated across the Southwestern US is the focus for the next few days.  The combination of upper level strong winds and series of disturbances rotating around this low will be the triggers for the active weather across the western half of the US.  At the surface, a warm front currently extends northwest into Texas while a low pressure system and cold front is farther west into the Four Corners Region.  These surface features will come together with the upper level system dynamics this afternoon and evening and create a favorable environment for severe weather.

Surface Weather Map on Monday, 11/16/2015

Surface Weather Map on Monday, 11/16/2015

NWS Storm Prediction Center has outlined an area of an Enhanced Risk for Severe Weather in western Oklahoma and parts of Northern Texas Today and into tonight.  A Slight Risk for severe weather extends from southwestern Nebraska South into Kansas, Oklahoma and Western and Central Texas.

 

NWS SPC explanation of the Severe Weather Outlook categories.

NWS SPC explanation of the Severe Weather Outlook categories.

 

The primary timing for the storms is this afternoon and evening. While the main concern is damaging winds where SPC has outlined an area of 30% risk for damaging winds in West Texas and Western Oklahoma, the potential for a few tornadoes is possible especially with the start of the activity.

damaging wind

Threat for damaging winds.

 

Threat for tornadoes

Threat for tornadoes

Individual thunderstorms are expected to form into a line and move east overnight which is why probabilities of 15% and higher for damaging winds extends into eastern Oklahoma and Texas.

While spring is a peak for severe weather in the Southern Plains, severe weather is actually not uncommon in the fall as well.  In the graphic below, areas outlined in light yellow show where significant wind reports (winds greater than 65 kts or 75 mph) have occurred between 1982 to 2011.  

svr climatology

Heavy rain in Southern Plains and Mississippi River Valley

Another impact from this low is heavy rain. Rainfall amounts of 1.0” to 2.5”+ of rain are expected from Northeastern Texas into Oklahoma Arkansas and Southern Missouri today and tonight. Heavy rain will continue into tomorrow as well where an additional 1.5” to ~ 4” of rain is expected in the Mississippi River Valley from Louisiana to Southern Wisconsin. In anticipation of the heavy rainfall, flash flood watches are in effect for much of the central and lower Mississippi River Valley.

qpf

 

watch and warnings

Heavy Snow and Blizzard Conditions

On the back side of the Four Corners Low, snowfall is the big story. Broad areas in the central and Southern Rockies as well as parts of the Central Plains are under Winter Weather Advisories and Winter Storm Warnings. A blizzard watch and warning is in effect for parts of northwestern Kansas, far southern Nebraska and Northeastern Colorado which includes the Denver area.   Blizzard conditions will develop tonight and continue into Tuesday.  Significant snows are expected. The graphic below shows the potential of 4+ inches of snow accumulation by Tuesday Morning. Areas of Aqua, orange and read show a higher confidence of at least 4 inches of accumulation by 5 am MST.

snowfall probs

With the heavy snow and winds between 25 and 40 mph with gusts to 60 mph, visibility of less than a quarter of a mile will be common in areas highlighted with a Blizzard Warning and potentially for those in the Watch. This will be a dangerous situation for anyone traveling; so it is recommended that  you make preparations today and if at all possible do not travel tonight and tomorrow during the height of the storm.

Heavy rain and Snow in Washington

The other story is the system approaching the Pacific Northwest. This system is bringing snow to the higher elevations and heavy rain to the lower elevations. Winter Weather Advisories, Winter Storm Warnings and Flood Watches are in effect in Western Washington. Rainfall amounts of 1” – 3” will be common along the coast with snows of 4 – 8+ inches possible, especially in the higher terrain through Wednesday Morning.

Preparation Activities

With the threat of damaging winds, consider bringing in any outdoor planters, toys, furniture and other items that may easily be lofted with 58+ mph winds. 

For those impacted by the winter storms and blizzard conditions, we recommend you check your supplies today. Ensure that you have extra water and food. Also in case you lose power, have an alternate source of heat. (Remember most gas heaters need electricity for their blowers/fans.)

If you are impacted by heavy rain, be mindful for localized flooding especially in creeks and streams and other low lying areas. Remember do not drive into a flooded roadway. Even if the water is not moving very quickly, you cannot be sure if the road surface is still intact.

Our Promise

The team at WxIntegrations will continue to provide relevant information and resources to help you better understand and prepare by incorporating weather impacts into your planning and response.

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