Outlook (Thursday-Sunday)

…Well below average temperatures, scattered winter precipitation through the weekend…

The end of the meteorological winter will be a cold one across Oklahoma.  While the forecast over the next four days is quite complex, it does look as if the air will be cold and precipitation will be falling at times.  There is considerable model to model, and run to run inconsistency that has the confidence in this forecast unusually low.

A cold front is moving southward across the state this Wednesday evening.  This spill of arctic air is in response to a strong upper wave moving southeastward across the Midwest.   A smaller wave is moving southeastward from the Central Rockies and snow (enhanced by upslope flow) is forming over eastern parts of Colorado and New Mexico.  Snowfall amounts over the western end of the Panhandle could reach 1 to 2 inches by Thursday morning.  For the remainder of the state, it will stay dry, but temperatures will be steadily falling.  Gusty north winds and temperatures in the 20s will result in uncomfortable wind chill by daybreak, Thursday.

On Thursday, an upper wave will be topping the Eastern Pacific ridge.  This wave will move rapidly southeastward, reaching the Southern High Plains by Friday morning.  More widespread snowfall is expected to develop over west Texas.  The models diverge here with the 18z GFS non-aggressive in moving this precipitation eastward.  The 00z NAM is in line with the 12z ECMWF in spreading accumulating snowfall eastward – mainly over the southern half of the state.  Given the GFS poor performance with the last system which was similar, will buy into a couple of inches of snow over southern Oklahoma and less than an inch over northern Oklahoma on Friday.  It will be very cold with temperatures hovering in the upper teens and low 20s.

After a short break in precipitation Friday night, yet another wave embedded in west southwest flow will begin to spread lifting over the state, generating more precipitation on Saturday morning.  Forecast soundings begin to make this a more difficult part of the forecast.  At daybreak, precipitation over the northern half of the state would be in the form of snow.  Near the Red River, precipitation is likely to transition to sleet.  By mid-day, this transition line will be shifting north toward the I-40 corridor.  During the afternoon, a mix of freezing rain and sleet appear likely across central Oklahoma.  Overall, precipitation with this wave does not appear to be very significant.  1 to 2 inches of snow/sleet are likely to fall with this wave.

Confidence for the Sunday portion of this forecast is very low.  An upper low will be located over the Southwest U.S. with numerous embedded waves generating lift and precipitation across Oklahoma.  For the most part, this precipitation will be on the light side.  The latest GFS and ECMWF suggest that enough low level warm air will move northward across the state to keep precipitation in the form of rain.  Both of these models have done fairly well of late with regard to the thermal profile.  With hesitance, will go ahead with the warmer solutions.  However, this air mass is quite cold and after a couple days of frozen precipitation, may be difficult to modify.  Light precipitation on Sunday morning could very well be in the form of freezing rain.   …Hazards…

Wind chill temperatures below 15 degrees will be common on Thursday, Friday, and Saturday mornings.  Snow may cause travel issues across southern and western Oklahoma on Friday.  A mix of winter precipitation could cause travel issues across most of the state on Saturday.

…Okarche Weather…

Thursday morning: 22

Thursday: 32

Friday morning: 18  / Snow possible

Friday: 26 / Snow possible

Saturday morning: 15 / Snow likely

Saturday: 32 / Snow and sleet likely

Sunday morning: 26 / Rain, freezing rain, and sleet possible

Sunday: 32

…PRECIPITATION CHANCES THROUGH SUNDAY…

CHANCE OF 0.01 INCH – 30%

CHANCE OF 0.10 INCH – 10%

CHANCE OF 0.50 INCH – 0%

CHANCE OF 1.00 INCH – 0%

CHANCE OF 2.00 INCH – 0%

CHANCE OF 3.00 INCH – 0%

…SNOWFALL CHANCES THROUGH SUNDAY…

CHANCE OF 1 INCH – 10%

CHANCE OF 3 INCHES – 0%

CHANCE OF 5 INCHES – 0%

CHANCE OF 7 INCHES – 0%

Snowfall – February 21-23, 2015

A complex winter weather event unfolded across Oklahoma over a three day period, from February 21st to 23rd.   There were many different mechanisms at play which produced several areas/bands of snowfall of varying duration and intensity.  While most of the state saw at least some snow, three areas saw significant accumulation.  The Panhandle and northwest Oklahoma,  along and north of the I-40 corridor, and across the Arbuckle Mountains and southeast Oklahoma.

Snow potential Wednesday

A small, but powerful upper level wave is located over Arizona/New Mexico this Tuesday evening.  The system will be moving quickly eastward across the Southern Plains during the day, Wednesday.  Precipitation is expected to develop across north Texas at daybreak Wednesday, as strong lifting spreads eastward.  Some of this precipitation will extend northward across the Red River.  Forecast thermal profiles are supportive of this being a snow event.  In general, 1 to 3 inches of snow is expected to fall along and north of the Red River.  However, some higher totals will be possible in areas where banding/training occurs.  Travel across far southern Oklahoma, as well as a large part of north Texas, will likely be impacted on Wednesday.

Records fall in Okarche

The total snowfall in Okarche on February 23rd was 3.7 inches.  This breaks the old record of 1.9 inches set in 2003.

In addition, the high temperature on the 23rd was 23 degrees.  This set a record for the lowest high temperature on the date.  The previous record was 30 degrees set in 1957.

Outlook (Monday-Wednesday)

…Week starts with snow and cold temperatures…

An upper level low over California and Nevada will begin moving eastward, shearing across the Southern Plains, reaching the Lower Mississippi Valley by mid-week.  Meanwhile, strong waves will continue to drop southward from the Canadian Prairies, which will keep arctic air in control over the central and eastern parts of the country.  There will be some modification of the cold air over Oklahoma on Wednesday, but temperatures will still only reach into the upper 40s and low 50s.

By daybreak on Monday, a lead wave will be moving across the Southern Plains.  Widespread snow is expected to develop and spread across the state during the daylight hours.  The heaviest precipitation will be across southern Oklahoma, where 1 to 3 inches of snow is possible.  Sleet is likely to be mixed with the snow along and just north of the Red River.  Amounts will decrease as you go north, and places along and north of I-40 are only likely to see an inch of snow or less.

Tuesday should be dry across the state.  As the main wave approaches early on Wednesday, more snow is expected to develop near the Red River.  Areas along and just north of the river may see an inch of snowfall before it ends by late morning.  Temperatures will begin to warm up during the afternoon on Wednesday, but this will be short-lived as another surge of arctic air reaches the state by evening.  It appears that there will be snow behind this front across parts of northern Oklahoma and the Panhandle, but significant accumulations are not expected at this time.

…Hazards…

Wind chill temperatures will be quite cold across the state on Monday.  Snowfall across the southern 2/3s of the state is likely to result in some travel problems.  The most significant issues will be confined to southern parts of the state.

…Okarche Weather…

Monday morning: 19 / Snow likely

Monday: 24 / Snow likely

Tuesday morning: 17

Tuesday: 41

Wednesday morning: 26

Wednesday: 49 / Light snow possible late

…PRECIPITATION CHANCES THROUGH WEDNESDAY…

CHANCE OF 0.01 INCH – 95%

CHANCE OF 0.10 INCH – 40%

CHANCE OF 0.50 INCH – 1%

CHANCE OF 1.00 INCH – 0%

CHANCE OF 2.00 INCH – 0%

CHANCE OF 3.00 INCH – 0%

…SNOWFALL CHANCES THROUGH WEDNESDAY…

CHANCE OF 1 INCH – 75%

CHANCE OF 3 INCHES – 2%

CHANCE OF 5 INCHES – 0%

CHANCE OF 7 INCHES – 0%

 

Winter weather update

A complex winter weather event will be unfolding across Oklahoma on Sunday and Monday.  It appears that most of the state will see at least some snow.  Northeast Oklahoma may only see about an inch of snow, but this long duration event is likely to accumulate at least 1 to 3 inches of snow across the remainder of the state.

There are two areas that appear to have the potential for higher amounts.

1) South central and southeast Oklahoma.  Two subtle waves embedded in west southwest flow will be tracking across the Southern Plains, generating widespread precipitation.  The first period of precipitation will start around Noon on Sunday and last for about 12 hours.  After a break, precipitation is expected to start around Noon on Monday and last through the daylight hours.  With about 18 hours of total snowfall, the potential exists for about 2 to 4 inches of accumulation.  Amounts greater than 4 inches would not be surprising should persistent banding set up.  Forecast soundings along and just north of the Red River suggest that some of the precipitation could fall as sleet.  Should this occur, overall accumulations would be limited.

2) Panhandle and western Oklahoma.  Snow is expected to develop across the Panhandle this Saturday evening, enhanced by low level upslope flow across eastern portions of Colorado and New Mexico.  Heavy snow will be possible through the morning hours of Sunday.  Bands of snow are expected to extend eastward across the main body of Oklahoma from early Sunday through Monday morning.  Again, the long duration of this event, combined with any persistent banding could result in as much as 3 to 5 inches of snow over parts of northwest Oklahoma.

Snow chances increase across parts of the state Saturday/Sunday

A cold front will move southward across Oklahoma early on Saturday.  Initially, the air behind the front won’t be all that cold.  However, a reinforcing surge of arctic air will begin moving southward across the state after sunset on Saturday.

Meanwhile, there will be several short wave troughs move across the Central and Southern Plains over the weekend – waves that will be ejecting out of a larger long wave trough expected to take shape west and north of Oklahoma.  These waves will generate precipitation across the state, with most of the precipitation expected to fall as snow.  Across most of Oklahoma, the snowfall will be very light with no significant accumulations expected through Midnight Monday.  Snowfall is expected to be enhanced by upslope flow over eastern sections of Colorado and New Mexico.  This activity is expected to spread eastward across the Panhandle and far northwest part of the state.  Snowfall amounts will increase the farther west you go, with as much as 3 to 5 inches of snow possible over the western Panhandle.

Outlook (Thursday-Sunday)

…Arctic air arrives over the weekend…

Another complex forecast over the next several days.  A long wave trough over the eastern part of the country will be swinging northeastward on Thursday and Friday.  Meanwhile, a ridge over the west will be flattening as numerous waves drop south from Canada.  One of the stronger waves will be moving across the Pacific Northwest on Friday, reaching the Central Plains by Saturday morning.  Another wave will be swinging southeastward from the Canadian Prairies.  The lead wave will result in deepening surface low pressure over Oklahoma on Saturday, while the trailing wave gets a significant piece of arctic air moving southward across the Plains.

South winds will be strong and gusty across Oklahoma on Thursday.  Temperatures across western Oklahoma will be mild Thursday and Friday, but with south and southeast winds, cold air over eastern Oklahoma will be difficult to erode.  There will be an increase in moisture on Friday, resulting in scattered showers and thunderstorms across the eastern half of the state.  By Saturday morning, the surface low will be exiting eastern Oklahoma and cold air will start to spread southward across the state.  Upslope enhanced snowfall is expected to develop over northeast New Mexico and eastern Colorado.  Some of this precipitation will likely move across the Panhandle and northwest Oklahoma on Sunday with light accumulations possible.

…Hazards…

Strong north winds will exist statewide from Saturday afternoon through Sunday.  Some gusts will be over 40 mph.

Accumulating snowfall will be possible over the Panhandle and northwest Oklahoma, Saturday night and Sunday.  Some travel problems may occur.

Okarche Weather:

Thursday morning: 19

Thursday: 48

Friday morning: 32

Friday: 51 / Slight chance of showers

Saturday morning: 35

Saturday: 53

Sunday morning: 31 / Chance of freezing rain and snow

Sunday: 31 / Chance of snow

PRECIPITATION CHANCES THROUGH SUNDAY:

CHANCE OF 0.01 INCH – 80%

CHANCE OF 0.10 INCH – 50%

CHANCE OF 0.50 INCH – 5%

CHANCE OF 1.00 INCH – 0%

CHANCE OF 2.00 INCH – 0%

CHANCE OF 3.00 INCH – 0%

SNOWFALL CHANCES THROUGH SUNDAY:

CHANCE OF 1 INCH – 60%

CHANCE OF 3 INCHES – 10%

CHANCE OF 5 INCHES – 0%

CHANCE OF 7 INCHES – 0%