Time for the main show of the 2015 storm season…

I used to consider the start of the storm season March 1st.  In reality, April 1st would have been closer to the truth.  There have been seasons where the first chase didn’t come until May.  Over the past few years, I have looked at the season as having two parts.  The first part is the appetizer, or salad, which covers March and April.  Any good chase during those months can be considered a bonus.  Sometimes the bonus is a big one, such as the multiple tornado day of April 14, 2012:

The meat and potatoes come in May and June, and here we are.  The bonus part of the season was a good one, filled with supercells and low end tornado events.  It’s also been a good year for large hail, and we have observed hail larger than baseballs on a couple of occasions.

There was one chase in March – on the 25th.  Severe storms were observed within an hour or so south and southwest of Okarche:

There were five chases in April.  On the 8th, we observed a nice looking supercell near Medicine Lodge, Kansas:

On the 11th, it was a beautiful supercell near Fritch, Texas:

The 16th saw numerous supercells over the Texas Panhandle and western Oklahoma.  We measured hail to 3.33 inches in diameter and observed three weak tornadoes:

Supercell storms were scattered across western Oklahoma on the 18th:

Impressive supercells were observed near Russell, Kansas on the 24th:

So now we enter the main part of the season.  It looks like the first few days of May will be slow, but we will be transitioning toward a more active period of storms across the Plains by the end of the first week.

Outlook (Thursday-Sunday)

…Mild temperatures / A few thunderstorms possible through the weekend…

The weather pattern through the weekend will be one in transition from a ridge over the western U.S. and a trough over the east, to a trough over the west with building heights over the east.

A strong upper wave is dropping south across the Great Lakes, helping to carve out a long wave trough over the eastern part of the country.  This trough will be shifting east of the east coast on Friday.  Flow will become more zonal by Saturday morning with a strong jet segment tracking eastward near the northern border of the U.S.  Heights over the western U.S. will begin to fall by the end of the weekend as a strong jet segment approaches Baja California.

Surface high pressure is located over the Plains this Wednesday evening.  It will be shifting east to the Mississippi Valley by late Friday.  Meanwhile, pressures over the High Plains will begin to fall.  A few showers and thunderstorms will be possible over eastern Colorado and New Mexico late on Friday.  It’s possible that some of this activity could move into the Panhandle overnight into early Saturday.  The case will be the same late on Saturday, and there are indications that some of the activity could move farther into northwest Oklahoma by early Sunday.

During the day Sunday, low pressure will begin to organize over southwest Kansas.  The pressure gradient will tighten across the state and winds will become gusty out of the south.  There will be an increase in moisture and a few showers and thunderstorms will be possible late in the day across northern and western Oklahoma.

…Hazards…

South winds on Sunday will be gusting between 30 and 40 mph across the state.

There will be a conditional risk of severe thunderstorms across northern and western Oklahoma on Sunday.  Should storms form, marginally severe wind and hail events will be possible.

…Okarche Weather…

Thursday morning: 47

Thursday: 79

Friday morning: 49

Friday: 80

Saturday morning: 52

Saturday: 83

Sunday morning: 54 / Slight chance of showers and thunderstorms

Sunday: 84 / Slight chance of showers and thunderstorms

…PRECIPITATION CHANCES THROUGH SUNDAY…

CHANCE OF 0.01 INCH – 20%

CHANCE OF 0.10 INCH – 10%

CHANCE OF 0.50 INCH – 5%

CHANCE OF 1.00 INCH – 1%

CHANCE OF 2.00 INCH – 0%

CHANCE OF 3.00 INCH – 0%

Precipitation

The total precipitation in Okarche on April 28th was 0.13 of an inch.  This brings the three day storm total to 1.95 inches.  On April 27th, a total of 1.63 inches of rain fell.  This was the first time since November 3, 2014 that a calendar day had at least one inch of rain.

With no further rain expected through the end of the month, the April total will be 4.49 inches.  This is 1.32 inches above the average – or 142 percent of average.  This marks the first time that a month has seen average or above average precipitation since September of 2014.

Outlook (Monday-Wednesday)

…Heavy rainfall expected through Monday night / Dry by Wednesday…

A deep upper level low pressure area over New Mexico this Sunday evening will move slowly east, reaching central Oklahoma by Tuesday morning.  The system will begin to open as it reaches eastern Arkansas by Wednesday morning.

A cold front is south of Oklahoma and winds across the state will remain out of the north or northeast through the middle of the week.

Widespread areas of heavy showers and thunderstorms will occur statewide through Midnight on Tuesday.  Some areas will see heavy enough rainfall for flash flooding.  The heaviest rainfall will begin to end early on Tuesday, and likely be finished by late afternoon.  Wednesday is expected to be dry.

Clouds and precipitation will keep temperatures cool on Monday and Tuesday.  Sunshine on Wednesday will allow temperatures to climb back to near 70 degrees.

…Hazards…

Flash flooding will be possible statewide on Monday.  The greatest threat will be across central and western Oklahoma.

…Okarche Weather…

Monday morning: 48 / Showers and thunderstorms likely

Monday: 52 / Showers and thunderstorms likely

Tuesday morning: 46 / Showers possible

Tuesday: 63 / Slight chance of showers

Wednesday morning: 45

Wednesday: 72

…PRECIPITATION CHANCES THROUGH TUESDAY…

CHANCE OF 0.01 INCH – 100%

CHANCE OF 0.10 INCH – 100%

CHANCE OF 0.50 INCH – 100%

CHANCE OF 1.00 INCH – 90%

CHANCE OF 2.00 INCH – 60%

CHANCE OF 3.00 INCH – 20%

Outlook (Thursday-Sunday)

…Active weather pattern will bring chances of severe thunderstorms…

A low amplitude ridge over the Central and Southern Plains early on Thursday will be shifting east by late in the day as a strong upper wave approaches from Northern Mexico. This wave will be moving across Oklahoma on Friday with an associated 80+ knot mid-level jet max.  Saturday will see heights rise slightly over the Plains, but this will be short-lived as another very strong upper system will be approaching the Southern Plains by late afternoon on Sunday.

Showers and thunderstorms will continue across the southeast part of the state through early Thursday.  Low pressure will begin to deepen near the western end of the Panhandle, and south winds will increase across the state.  This will result in a significant increase in low level moisture.  There are mixed signals in model data regarding thunderstorm potential on Thursday.  Present thinking is that the lack of any identifiable forcing mechanisms should keep most of the state dry.  However, a couple of late afternoon storms will be possible and any that do form will have the potential to be severe.

Deep low pressure will take shape across western Kansas on Friday.  Early in the day, there will be a considerable amount of showers and thunderstorms form across Texas which will spread northeastward across the southeast part of the state.  A dryline will begin advancing eastward across Oklahoma, and this feature will provide a focus for showers and thunderstorms during the late afternoon and evening hours.  The precipitation / including the potential for severe storms / will be confined to areas east of I-35.

Saturday is the only day in the forecast period that is expected to remain dry.

On Sunday, low pressure will organize over the Texas Panhandle in response to the next system to approach the Plains.  A moist and unstable air mass will be found across the state and there will be frontal and dryline features in the area.  Thunderstorms / some severe / are expected during the late afternoon and evening hours.

…Hazards…

Isolated severe storms will be possible on Thursday.

Severe thunderstorms will be possible across the eastern half of the state on Friday, and statewide on Sunday.

…Okarche Weather…

Thursday morning: 49

Thursday: 70 / Slight chance of showers and thunderstorms

Friday morning: 62

Friday: 82 / Slight chance of showers and thunderstorms

Saturday morning: 57

Saturday: 84

Sunday morning: 55

Sunday: 78 / Showers and thunderstorms possible

…PRECIPITATION CHANCES THROUGH SUNDAY…

CHANCE OF 0.01 INCH – 80%

CHANCE OF 0.10 INCH – 60%

CHANCE OF 0.50 INCH – 40%

CHANCE OF 1.00 INCH – 20%

CHANCE OF 2.00 INCH – 2%

CHANCE OF 3.00 INCH – 0%

Outlook (Monday-Wednesday)

…Weather pattern to remain an active one…

Strong cyclonic flow will persist through mid-week from the Canadian Prairies to the Midwest to the Northeast U.S. around an upper low which will be located just north of the Great Lakes.  This will continue to allow seasonably cool temperatures to move southward across the Plains and Midwest.  Meanwhile, a very active subtropical jet will continue to flow across Northern Mexico and the southern states.  An upper low will be approaching the Southern Plains, and by Wednesday this feature will be located over Arizona with moderately strong flow spreading northeastward across New Mexico and Texas.

Temperatures Monday will start cool as surface high pressure settles across the state.  By late afternoon and evening, this high will be southeast of the state and return flow will begin over west Texas and the panhandles.  By late in the day, scattered showers and thunderstorms are likely to form over the panhandles.  This activity will move east across Oklahoma during the overnight hours, and continue over eastern Oklahoma on Tuesday.  A cold front will be approaching northern Oklahoma by Midnight on Wednesday.  Showers and thunderstorms will be possible near this boundary, as well as in a warm air advection regime across central and southern Oklahoma during the early morning hours of Wednesday.  The cold front will slip southward reaching the I-40 corridor by Noon, as low pressure begins to organize across the Texas South Plains.  With a steady increase in moisture, and a front in the area, several rounds of showers and thunderstorms will be possible statewide, Wednesday afternoon and evening.  Some severe weather will be possible, with the main threat being large hail.

…Hazards…

Patchy frost will be possible across the Panhandle and northern Oklahoma on Monday morning.

Severe thunderstorms will be possible across most of Oklahoma on Wednesday.

…Okarche Weather…

Monday morning: 37

Monday: 66

Tuesday morning: 42 / Showers possible

Tuesday: 74 / Showers and thunderstorms possible

Wednesday morning: 53 / Showers and thunderstorms likely

Wednesday: 71 / Showers and thunderstorms likely

…PRECIPITATION CHANCES THROUGH WEDNESDAY…

CHANCE OF 0.01 INCH – 100%

CHANCE OF 0.10 INCH – 90%

CHANCE OF 0.50 INCH – 70%

CHANCE OF 1.00 INCH – 30%

CHANCE OF 2.00 INCH – 5%

CHANCE OF 3.00 INCH – 1%

Outlook (Thursday-Sunday)

…Showers and thunderstorms expected through the weekend…

A deep upper level low pressure area is located near the Four Corners this Wednesday evening.  This low is expected to wobble eastward reaching the Central Plains by Sunday morning.  The system will be opening up and lifting northeast on Sunday, ahead of a strong upper wave dropping southeastward from the Northern Rockies.

Surface low pressure will be located near the western end of the Oklahoma Panhandle, Thursday afternoon.  A dryline will extend southward through western Texas.  This dryline will be a focus for afternoon thunderstorm development – some of which will be severe.  Areas of showers and thunderstorms will advance eastward across the western half of the state through Friday morning.

On Friday, showers and thunderstorms will continue across eastern Oklahoma, while new precipitation forms over the western part of the state during the afternoon and evening.  Once again, some of the storms could be severe.

A dryline will be located over western Oklahoma on Saturday.  This feature will be the focus for more thunderstorm development.  Severe storms are likely.  The precipitation will finally start to end over eastern Oklahoma by Sunday afternoon.

…Hazards…

Severe thunderstorms will be possible across the western half of the state on Thursday.  A few strong storms will be possible across most of the state on Friday.  Severe thunderstorms will again be a risk across the main body of Oklahoma on Saturday.

…Okarche Weather…

Thursday morning: 53

Thursday: 79 / Showers and thunderstorms possible

Friday morning: 58 / Showers and thunderstorms possible

Friday: 69 / Showers and thunderstorms possible

Saturday morning: 57 / Showers and thunderstorms possible

Saturday: 80 / Showers and thunderstorms possible

Sunday morning: 54

Sunday: 70

…PRECIPITATION CHANCES THROUGH SUNDAY…

CHANCE OF 0.01 INCH – 100%

CHANCE OF 0.10 INCH – 100%

CHANCE OF 0.50 INCH – 100%

CHANCE OF 1.00 INCH – 80%

CHANCE OF 2.00 INCH – 30%

CHANCE OF 3.00 INCH – 10%

Outlook (Monday-Wednesday)

…Rain is coming – promise!…

An upper low approaching Oklahoma this Sunday evening will move slowly across the Southern Plains, weakening some over west Texas by Tuesday morning.  The remnant open wave will finally shift east of the state by Wednesday afternoon.  Meanwhile, a strong upper low will dig southeastward, reaching the Four Corners by late Wednesday.

A cold front is in the progress of moving south across Oklahoma, and by Monday afternoon it will be located near the Red River.  The air behind this front is not very cold, but combined with precipitation and cloud cover, afternoon highs on Monday and Tuesday will be somewhat cool.

By Wednesday afternoon, deep surface low pressure will be organizing over eastern Colorado.  This will result in an increase in south winds across the state and temperatures should return closer to average.

Now for the good news.  Widespread showers and thunderstorms will spread across the state overnight (except for the Panhandle), with most areas of the state seeing beneficial rainfall.  By Monday afternoon, the precipitation should be confined to areas south of I-40.  Precipitation chances go down on Tuesday, but don’t completely go away.  A scattered shower or thunderstorm will be possible across most sections of the state.  By Wednesday, precipitation chances will be confined to southeast Oklahoma, and also the Panhandle and northwest as new areas of storms form near an approaching front.

…Hazards…

A few strong and heavy rainfall producing thunderstorms will be possible across central and southern Oklahoma on Monday.

There will be a chance of a few strong thunderstorms over the Panhandle and northwest on Wednesday.

…Okarche Weather…

Monday morning: 54 / Showers and thunderstorms likely

Monday: 57 / Showers and thunderstorms possible

Tuesday morning: 51

Tuesday: 57 / Slight chance of showers and thunderstorms

Wednesday morning: 47

Wednesday: 74

…PRECIPITATION CHANCES THROUGH WEDNESDAY…

CHANCE OF 0.01 INCH – 100%

CHANCE OF 0.10 INCH – 100%

CHANCE OF 0.50 INCH – 90%

CHANCE OF 1.00 INCH – 1%

CHANCE OF 2.00 INCH – 0%

CHANCE OF 3.00 INCH – 0%

Outlook (Thursday-Sunday)

…Severe weather possible over southeast Oklahoma on Thursday / Storm chances return over the weekend…

An upper wave will move across the Central Plains and Midwest on Thursday.  A weak ridge will try to become established on Friday and Saturday, but an upper low will approach the Southern Plains on Sunday.

A cold front will be moving across central Oklahoma at daybreak on Thursday.  This front will provide a focus for showers and thunderstorms / some severe / across southeast Oklahoma during the afternoon hours.  High pressure will spread across the state on Friday, and the day will start out cool.  As the high shifts east of Oklahoma on Saturday, winds will return from a southerly direction and temperatures will warm into the 70s.  There will be an increase in low level moisture across the Southern Plains and scattered showers and thunderstorms will be possible across most of the state.  While no significant severe weather is expected, a few of the storms may be quite strong.  Low pressure will be located over west Texas on Sunday afternoon as an upper low approaches from the southwest.  A front will extend from the surface low, northeastward to north central Oklahoma.  Widespread showers and thunderstorms are expected to form across most of the state during the afternoon and evening hours.  No widespread severe weather is expected, but once again, some of the storms could be strong.  While it’s hard to predict rain during a drought, it appears that some heavy rainfall totals may be in store for drought stricken areas.

…Hazards…

Severe thunderstorms will be possible across southeast Oklahoma on Thursday.

Strong to isolated severe storms are possible over the Panhandle and western Oklahoma on Saturday – and across most of the state on Sunday.

Flash flooding may become a possibility on Sunday.

…Okarche Weather…

Thursday morning: 64

Thursday: 73

Friday morning: 38

Friday: 69

Saturday morning: 45

Saturday: 73

Sunday morning: 61 / Showers and thunderstorms possible

Sunday: 80 / Showers and thunderstorms likely

…PRECIPITATION CHANCES SATURDAY AND SUNDAY…

CHANCE OF 0.01 INCH – 100%

CHANCE OF 0.10 INCH – 100%

CHANCE OF 0.50 INCH – 90%

CHANCE OF 1.00 INCH – 70%

CHANCE OF 2.00 INCH – 50%

CHANCE OF 3.00 INCH – 20%

Outlook (Monday-Wednesday)

…Active weather week in store for Oklahoma…

Models are in reasonably good agreement concerning the weather across the state Monday through Wednesday.

An upper level low pressure area just off the coast of the Pacific Northwest will dig southeastward, reaching the Central Rockies by Wednesday.  There will be moderate west southwest mid-level flow over the Plains on Monday and Tuesday.  On Wednesday, flow will sharply increase as phasing jet segments associated with the Central Rockies low spread northeastward across Texas, Oklahoma and Kansas.

Moisture is plentiful from Texas to the Lower Mississippi Valley this Sunday evening, with precipitable water values approaching 2 inches over southeast Texas.  Slugs of very moist air will continue to flow northward across the eastern 2/3s of the state – to the east of a dryline – through Wednesday.

Extensive cloud cover and light precipitation has kept temperatures well below forecast values over the eastern half of the state today (Sunday).  So much so, that temperatures will actually be warming overnight with lows Monday morning higher than some highs on Sunday.

On Monday, low pressure will be organizing near the Kansas/Colorado border.  A dryline will progress eastward during the day, reaching almost to the Highway 81 corridor by late afternoon.  As this occurs, very warm and dry air will spread across western Oklahoma and the Panhandle on gusty southwest winds.  Fire danger will be very high west of the dryline.  East of the dryline, temperatures will be mild or warm, and it will be quite moist.  Strong capping is expected to limit the threat of thunderstorm development along the dryline.

A weak mid-level impulse will get the surface low moving east across Kansas on Tuesday.  As this occurs, a cold front will be moving southward and approach the Kansas/Oklahoma border before becoming nearly stationary.  After an overnight retreat, the dryline will push farther into Oklahoma and extend from near Ponca City to near Lawton by late afternoon.  Fire danger will once again be elevated west of the dryline.  Thunderstorms will be possible near the front over southeast Kansas and adjacent areas of Oklahoma.  There are some indications that the cap may be breached in a couple of spots along the dryline near the I-35 corridor.  If this occurs, rapid severe thunderstorm development would be possible.  Any storms that do form would be isolated, and no broad areas of precipitation are expected.  Given the degree of instability and shear – should storms form – they would be capable of becoming supercell in nature with all facets of severe weather possible.  By late Tuesday, surface pressures will begin falling over eastern Colorado and western Kansas in advance of the approaching upper storm system.

On Wednesday, a deep surface cyclone will be found near the Kansas/Colorado border.  The dryline which will have had retreated overnight will make a quick advance eastward, reaching the Highway 81 corridor by afternoon.  This will be in response to a strong jet segment ejecting from the base of the Central Rockies upper low.  The atmosphere east of the dryline will be moist and highly unstable with MLCAPE expected to reach values of 2500 to 3000 j/kg.  500 mb winds approaching 70 knots will be overspreading a 40 to 50 knot low level jet.  Forecast soundings show wind profiles very supportive of supercell storms.  Forecast hodographs show impressive low level turning.  Rapid development of supercell storms will be possible by mid to late afternoon.  The most favored area will be along the dryline north of I-40, but isolated storms will also be possible to the Red River.  Storms that form will be capable of producing very large hail and damaging winds, along with tornadoes – some possibly strong.

The dryline is expected to retreat through western Oklahoma, before making another surge eastward during the overnight hours into Thursday morning.  The redevelopment of severe storms will certainly be a possibility as this occurs.

…Hazards…

Fire danger will be very high to extreme over western Oklahoma and the Panhandle – behind the dryline – Monday through Wednesday.

An isolated severe storm will be possible across central and eastern Oklahoma, Tuesday afternoon and evening.

More widespread severe storms are expected across central and eastern Oklahoma, Wednesday afternoon and through the overnight hours into Thursday.

…Okarche Weather…

Monday morning: 54

Monday: 84

Tuesday morning: 62

Tuesday: 89 / Slight chance of showers and thunderstorms

Wednesday morning: 64 / Slight chance of showers and thunderstorms

Wednesday: 85 / Showers and thunderstorms possible

…PRECIPITATION CHANCES THROUGH WEDNESDAY…

CHANCE OF 0.01 INCH – 90%

CHANCE OF 0.10 INCH – 90%

CHANCE OF 0.50 INCH – 50%

CHANCE OF 1.00 INCH – 20%

CHANCE OF 2.00 INCH – 10%

CHANCE OF 3.00 INCH – 5%