Outlook (Thursday-Sunday)

A large upper level low pressure area centered over Iowa this afternoon will begin to open up and lift over the Great Lakes on Thursday.  The positive tilted trailing trough will drag across Oklahoma early on Friday.  By Saturday, the weather pattern across the country will transition to mostly zonal flow with a low amplitude ridge over the Rockies and the strongest flow aloft spreading eastward along the Canada/U.S. border.  The ridge will shift eastward over the Plains on Sunday as the next major system to affect the Plains organizes near the west coast.  This system will likely result in severe weather over the Plains over a several day period during the coming week as we enter a climatologically favorable period for severe thunderstorms.

No precipitation is expected in Oklahoma through the weekend.  Surface high pressure will gradually be replaced as pressure falls occur over the High Plains, eventually evolving into organized low pressure over Western Kansas on Sunday.  The result will be weakening northwest winds on Thursday, fairly light winds on Friday, and increasing south winds on Saturday and Sunday.

The headline weather story for Oklahoma will be a rapid warming trend, with hot conditions expected across portions of the state on Saturday and Sunday.  Thursday may see some frost across Northern and Eastern Oklahoma with afternoon highs once again below normal.  Even cooler conditions will be possible on Friday morning when frost will be possible across the northeast half of the state, and a light freeze may occur over Northeast Oklahoma.  Highs on Friday will be a little closer to normal.  A big warm up will start on Saturday when most places in Oklahoma will see highs in the 80s and Southwest Oklahoma will see highs in the 90s.  The warming trend will continue Sunday when 90′s will be possible across the western half of the state.  By Monday, some temperatures over far Southwest Oklahoma could reach 100 degrees.

Okarche Weather:

Thursday morning: 39

Thursday: 66

Friday morning: 37

Friday: 76

Saturday morning: 49

Saturday: 92

Sunday morning: 59

Sunday: 97

Outlook (Monday-Wednesday)

A very deep upper level low pressure area over the Central Plains is expected to wobble northeastward through midweek – reaching the Upper Midwest and Western Great Lakes.

A cold front/dryline has moved across the state and temperatures on Monday will be closer to normal.  There will be another surge of cool air across the state early on Tuesday which will drop temperatures to slightly below normal.  Another below normal day is expected on Wednesday.

Weak short wave troughs rotating around the upper low will result in scattered showers across portions of Central and Northern Oklahoma both Monday and Tuesday.  Significant accumulations are not expected.

The wind forecast is slightly complicated and there will be periods of strong winds in the state through Wednesday.  Winds will likely increase out of the northwest across the northern half of the state on Monday with gusts to near 40 mph possible.  On Tuesday, strong northwest winds will occur over the western half of the state with gusts in the main body of Oklahoma around 40 mph and gusts in the Panhandle over 50 mph.  On Wednesday, gusty winds will be confined to the Panhandle.

Okarche Weather:

Monday morning: 52

Monday: 72 / Showers possible

Tuesday morning: 49

Tuesday: 64 / Showers possible

Wednesday morning: 39

Wednesday: 63

Severe weather threat in Oklahoma on Saturday

A very strong storm system just off the west coast will move across the Rockies on Saturday with increasing lift spreading across the Plains late in the day.

In response to the approaching system, an intense surface cyclone will form over Northeast Colorado.  A dryline will extend from Nebraska and Kansas southward along the Texas/Oklahoma border.  The dryline marks the western side of a plume of returning low level moisture where afternoon dew points will reach into the 60s.

Increasing moisture and warm afternoon temperatures will lead to the atmosphere becoming potentially very unstable with MLCAPE values exceeding 2500 j/kg over Western Oklahoma.  A strong capping inversion will prevent thunderstorm development for most of the afternoon.

Strong heating/mixing near the dryline, combined with surface convergence and increasing lift from the approaching system will be sufficient for thunderstorms to form after 5 pm.

Forecasting the exact evolution of thunderstorms through the late afternoon and evening hours is problematic.  If the cap is slightly stronger than forecast, storm initiation may not occur until very late in the day.  A slightly weaker cap would result in storms forming earlier in the afternoon.  Later storms would likely remain slightly elevated, limiting the primary severe threat to large hail.  Earlier storm formation would result in more surface based storms with time, and an increase in the tornado threat.

Given the degree of instability and deep layer shear, supercell storms are expected to form with at least a narrow window where there will be a tornado threat.  Otherwise, very large hail and damaging winds will be possible from established and long-lived supercells.

The most likely area for initial storm development will be over far Southwest Oklahoma.  These storms will spread northeastward across Central Oklahoma in the 10 pm to Midnight period.  By that time, the primary severe threat should be large hail, but the tornado threat cannot be considered zero.  More isolated severe storms will be possible over Northwest and North Central Oklahoma.  After Midnight, severe thunderstorms will be advancing into Eastern Oklahoma where the threat will continue well into the early morning hours.

The range of severe potential on Saturday is broad.  A low end event may yield a couple of storms with marginal severe threats.  The upper end of the range of potential would include several significant supercell storms capable of producing very large hail and tornadoes.  In all likelihood, a good idea of what is going to occur will not likely happen until storms first start to organize.

At this time, there is no reason to alter normal activities, but people should be aware of an increasing threat of severe weather during the late afternoon and evening hours… monitor weather information… and be prepared to act should watches or warnings be issued.

Outlook (Thursday-Sunday)

A compact, but strong storm system will finish moving across Oklahoma on Thursday.  Scattered showers and thunderstorms will remain possible across mainly Central and Eastern Oklahoma through the afternoon.  A cold front will move across the state with gusty northwest winds expected behind it.

Warm weather with increasing south winds will be found across Oklahoma on Friday and Saturday in advance of the next system to affect the state.

An unusually strong open wave of low pressure will push across the Rockies on Saturday, then close off and slow down over the Central Plains on Sunday.  The surface reflection of this storm will be an intense cyclone to the north of the state.  A dryline will be located near the western Oklahoma border with a moist and potentially very unstable atmosphere found across the main body of the state.  While the atmosphere will remain capped through most of the afternoon, lifting associated with the approaching storm will likely cause scattered showers and thunderstorms to form during the evening and overnight hours into Sunday.  Given the degree of instability and shear, these storms will have the potential to be supercell in nature with all facets of severe weather possible.  Nocturnal tornadoes are fairly rare in Oklahoma, but this is an unusually strong storm system and it appears that potential will exist Saturday night.

The dryline will have pushed east of I-35 on Sunday, and there will be a risk of severe thunderstorms over Eastern Oklahoma.  Cooler air behind a cold front will begin to filter into Northwest Oklahoma and the Panhandle by late in the day on Sunday.

Okarche Weather:

Thursday morning: 64 / Showers and thunderstorms possible

Thursday: 71

Friday morning: 48

Friday: 79

Saturday morning: 58

Saturday: 86

Sunday morning: 65 / Showers and thunderstorms possible

Sunday: 83

Severe thunderstorms likely on Wednesday

A fairly strong trough of low pressure will move eastward across the Rockies on Wednesday – with increasing flow and lift spreading across the Plains.  Deep surface low pressure will organize over Western Kansas – and by late afternoon a dryline will be located over the eastern portions of the Oklahoma and Texas panhandles.

East of the dryline, the atmosphere will become quite unstable through the afternoon as low level moisture increases.  There are still some questions regarding the quality of moisture that is able to return, but models are in good agreement that there should be sufficient moisture to support severe thunderstorms.

Deep layer shear will be moderate to strong and supportive of rotating updrafts.  Thunderstorms are expected to form near or just after 4 pm.  Given the degree of instability and shear – the storms should quickly become severe.  Supercell storms are possible and these will be capable of generating a few significant severe weather events.  Hail to the size of baseballs and an isolated tornado will be possible with the more significant storms.

While the severe potential will begin to wane as the storms move toward Central Oklahoma, there will still likely be marginally severe storms all the way east to near the I-35 corridor by 10 pm.

Record precipitation

The total precipitation in Okarche on April 21st was 0.49 of an inch.  This set a record for the date.  The previous record was 0.21 of an inch set in 1995.

In addition, this is the most precipitation in a day so far this year.  The last time that much precipitation fell was on December 21st, 2013.

Outlook (Monday-Wednesday)

The primary storm track extends from the Pacific Northwest eastward near the Canada/U.S. border.  A strong trough of low pressure is located over the Eastern Pacific.  A wave of low pressure is located in the weaker southern flow and is moving across the Southern Plains.

In the near term, showers and thunderstorms across Oklahoma will continue to advance eastward with the heaviest precipitation expected to remain across Southern and Eastern Oklahoma.  Model data supports a redevelopment of showers and thunderstorms on Monday across most of the main body of Oklahoma.  Precipitation should come to an end by Monday evening.

Attention then turns toward the Eastern Pacific trough.  Models are in excellent agreement regarding the track and intensity of this system.  It will be moving across the Western U.S. on Tuesday and the Rockies on Wednesday.  By Wednesday, southwest flow aloft and increasing lift will begin to spread across the High Plains.

A weak surface front will settle southward across the state on Monday.  This boundary will become less recognizable on Tuesday as south winds return across the state in response to deepening low pressure northwest of Oklahoma.

On Wednesday, deep low pressure will be located over Southwest Kansas.  A dryline will extend southward across the eastern Texas and Oklahoma panhandles.  There will be a steady increase in low level moisture and resultant instability.  Deep layer shear will become supportive of rotating updrafts.  Thunderstorms are expected to form along the dryline by mid to late afternoon.  Given the degree of instability and shear, severe thunderstorms appear likely as they spread into Western Oklahoma.  Thunderstorms / some severe / will continue to advance eastward into Central sections of the state late in the day.

Okarche Weather:

Monday morning: 56 / Showers possible

Monday: 74 / Showers and thunderstorms possible

Tuesday morning: 48

Tuesday: 77

Wednesday morning: 53

Wednesday: 83 / Showers and thunderstorms possible