A considerable number of small differences with potential significant impacts exist across the suite of models this morning, leading to less than normal confidence in the forecast. It is expected that a strong upper level low over Nevada will open up and lift toward the Northern Plains by Tuesday morning, as a strong mid level jet max rotates around the eastern side of the low. The wave will lift toward Southern Manitoba by Wednesday. In its wake, a band of moderately strong mid level flow will carve out a broad trough over the Western U.S. There are several differences in model solutions with regard to timing and the strength of waves that will be embedded in the flow.
The weather will be mild across the state on Monday with southerly winds and temperatures slightly above normal. On Tuesday, a deep surface cyclone associated with the lead wave will be moving northeast across the Dakotas, with a trough extending southward to a secondary low near the Kansas/Colorado border. A dryline will extend from this low southward across the eastern parts of the Oklahoma and Texas panhandles. Low level moisture will gradually increase east of the dryline, and by late afternoon the atmosphere will become moderately unstable. The 18z GFS suggests that a wave embedded in the mid level flow will be moving across the High Plains. This combined with afternoon heating and convergence along the dryline should be sufficient for the development of scattered showers and thunderstorms. Storms over Western Oklahoma late on Tuesday will spread across the northern half of the state through Wednesday morning. A few of the storms may be severe with a hail and damaging wind threat. Tuesday will be another day with temperatures slightly above normal.
A greater risk of severe thunderstorms will come on Wednesday. As a dryline pushes eastward toward Central Oklahoma, a surface low will be located along it near the Kansas border. Moisture should be deep enough by Wednesday to result in a very unstable atmosphere east of the dryline. Once again, afternoon heating, convergence along the dryline and subtle mid level lifting will be sufficient for the development of storms, with the greatest threat near the surface low over North Central and Northeast Oklahoma. Large hail and damaging winds will once again be possible, but forecast soundings and hodographs suggest that a low end tornado threat will also exist. Temperatures on Wednesday will be above normal, but a cold front will enter Northwest Oklahoma late in the day and cooler air will begin to filter into the state.
Monday morning: 61
Tuesday morning: 63
Wednesday morning: 66 / Showers and thunderstorms possible
Wednesday: 89 / Showers and thunderstorms possible
12z EURO and GFS are in nice agreement with primary features through the weekend. A strong upper low will move onshore over the west coast Friday afternoon and then lift northeastward toward Salt Lake City by Sunday. The flow over the central and eastern part of the country will be quite weak, with meandering disturbances that are not expected to have a significant impact on Oklahoma.
A few light showers will be possible over the Panhandle through Thursday morning. Afterward, no precipitation is expected across the state through the weekend.
A surface trough will be located over the High Plains through Sunday. Winds across the state will remain out of the south, and could become gusty at times over the Panhandle.
Temperatures through the period will be near or slightly above normal.
Thursday morning: 58
Friday morning: 58
Saturday morning: 59
Sunday morning: 60
A trough of low pressure is located over the Eastern U.S. with a ridge over the western part of the country. Sliding through the ridge is a weak cut off low which is located over Nevada this evening. The low is expected to open up as it approaches the Plains late on Monday. The trough will slowly track across the Plains on Tuesday, and lift across the Midwest on Wednesday.
Surface high pressure over the Central Plains will move east and pressures will begin to fall on Monday over the High Plains – this in response to the approaching upper system. Showers and thunderstorms are expected to develop over the Central High Plains on Monday afternoon, and precipitation is expected to spread eastward toward the Midwest on Tuesday and Wednesday. The southern extent of this precipitation is expected to track across the Panhandle and Northern Oklahoma. The best chances of precipitation across the main body of Oklahoma will come from late on Tuesday to Wednesday afternoon.
Temperatures are expected to be slightly below normal on Monday and close to normal on Tuesday and Wednesday.
Monday morning: 55
Tuesday morning: 58
Wednesday morning: 60 / Showers possible
A cold front is moving southward across Kansas this afternoon. A complex of showers and thunderstorms have already organized near this boundary over Northeast Kansas. Other showers and thunderstorms are expected to form westward toward Central and Southern Kansas and begin moving south or southwestward toward Oklahoma. Most of the precipitation will hold off until Midnight or after, and the best chance of measurable precipitation will be across North Central and Northwest Oklahoma.
The front will make it to near the Red River by Sunday afternoon. Other showers and storms will be possible across Southern Oklahoma during the afternoon and evening on Sunday. Temperatures behind the front will not be all that cool, and highs over Central Oklahoma will be near normal (about 85 degrees).
An upper air disturbance over West Texas and New Mexico is likely to stay well southwest of Oklahoma through the weekend. As a result, precipitation chances have been reduced further. It now appears that no significant rainfall will occur across Central Oklahoma. Southwest Oklahoma may still see some isolated heavy showers which could produce upward of 3/4 of an inch of rainfall.
The next chance of rainfall for Central Oklahoma may come with a cold front that will pass across the area on Sunday.
An upper air disturbance (remnants of Hurricane Odile) will be responsible for heavy rainfall and flooding over much of West Texas and Southern New Mexico through the weekend. It is becoming more and more likely that significant rainfall will stay to the southwest of Oklahoma.
Model trends over the last 24 hours suggest that the disturbance will not be picked up by a strong trough moving from the Canadian Prairies to the Great Lakes and Mississippi Valley. Instead, rapid strengthening of a high pressure area over the Southern Rockies will likely steer the disturbance slowly back toward the southwest.
By early Saturday, showers and thunderstorms are expected to move into Southwest Oklahoma, near a plume of high PW values. The high moisture values are not expected to hang around long as drier air moves south across the Plains in association with the strong/large trough developing to the east of Oklahoma.
By Saturday evening, heavy precipitation should be coming to an end across the state. Some parts of Southwest Oklahoma may see rainfall amounts between 3/4 and two inches. Other precipitation across the state on Saturday will be lighter, mostly between 1/4 and 3/4 of an inch.
The evolution of the weather pattern over the next several days appears quite complex. 00z model data has been delayed, so the majority of this forecast is coming from a blend of 12z EURO / 18z GFS / 00z GFS. Given the complexity of the pattern, the forecast will be somewhat generalized, avoiding trying to hammer out minor details.
Weak upper air disturbances are noted this evening over Missouri and over the Texas South Plains. Lifting associated with the Missouri trough has been responsible for a complex of thunderstorms which have propagated southwestward from Western Missouri/Arkansas. Short range models maintain some showers and storms through Thursday morning as this activity works toward South Central Oklahoma. Meanwhile, there have been showers and thunderstorms over West Texas which will likely work into Southwest Oklahoma. Models are also suggestive of more storms forming overnight in Kansas, and some of this activity may reach Northern Oklahoma. Despite all of these areas of precipitation, rain may very well skirt around the Okarche area.
A long wave trough is currently moving onshore over the west coast. This system will shear northeastward toward the Northern Plains by Friday. As it does, the remnants of Hurricane Odile / currently located over Southeast Arizona / will be picked up and ejected toward the Southern and Central Plains. The weakening system will be moving over Oklahoma on Saturday and will be absorbed by a developing trough over the Eastern U.S. by Sunday.
Over the next 24 hours, a variety of lifting mechanisms will result in scattered precipitation, especially over Eastern and Southern Oklahoma. Starting Friday afternoon, showers and storms will be driven mostly by the ex-Odile system as it moves east northeastward from the Southern Rockies. Deep and rich moisture will be found across the state from Friday to Sunday, with PW values in excess of 2 inches expected. Precipitation will have spread across the northwest third of the state by Saturday morning. Some of the rainfall could be quite heavy. Precipitation will continue across the northwest half of the state throughout Saturday, and once again some heavy rainfall will be possible.
By Saturday evening, a cold front is expected to drop into Northwest Oklahoma. This front will become nearly stationary near the I-44 corridor by Sunday morning. The front and excessive amounts of moisture will keep precipitation in the forecast through Sunday, but by afternoon the rain should be limited to eastern and southern sections of the state.
Thursday morning: 72
Friday morning: 71
Saturday morning: 68
Saturday: 87 / Showers possible
Sunday morning: 68
Sunday: 86 / Showers possible
Model data continues to bounce regarding the track of Odile through the weekend. In general, the remnant system is expected to turn to the northeast and move toward the Plains. The exact path has varied from model to model and run to run. However, the GFS ensemble this morning has become more tightly clustered in getting the system to Central and Southern New Mexico over the next 48 hours. The 12z operational GFS paints a slug of deep and rich moisture surging into the state from about Noon on Friday to about Noon on Sunday, with PW values in excess of 2 inches. The National Weather Service in Norman has stepped a little bit out on a limb with a forecast of 2 1/2 to 3 inch rainfall over much of Central Oklahoma. They have left themselves an out stating that the forecast is likely to change. Anyone with outdoor plans this weekend should pay attention to forecasts over the next few days. It still appears that there is a wide range of possibility from scattered showers to flooding rainfall.
Latest tropical guidance is not tightly clustered, but does continue to show the remnants of Odile making a turn toward the east northeast over the next 48 to 72 hours. The last GFS run has shifted the track of the system farther south, impacting more of Oklahoma during the Friday-Sunday time frame. Forecast PW amounts across the state exceed 2.2 inches on Saturday. While it is still far enough out to limit confidence, a heavy rain event by the end of the week and weekend is still a possibility.
Hurricane Odile is an Eastern Pacific storm that made landfall near Cabo San Lucas late yesterday evening. The National Hurricane Center reports that the estimated intensity of the hurricane at landfall was 110 knots, which ties with Hurricane Olivia (1967) as the strongest hurricane to make landfall in the satellite era, in the state of Baja California Sur.
Odile will start a rapid weakening trend soon, as it moves northwest and eventually turns toward the northeast. It will make the northeastward turn as it rounds an upper high over Northern Mexico and gets picked up by a progressive long wave trough that is approaching the west coast.
Currently, the operational GFS brings the remnant system across Eastern Arizona, Northern New Mexico, the Oklahoma Panhandle, and Kansas. However, this is well north of the GFS Ensemble guidance which is clustered over Central and Southern New Mexico and West Texas.
An already moist atmosphere will likely become more moist with the approach of Odile. Rainfall can be excessive with these remnant systems.
In late September of 1986, the remains of Hurricane Paine moved across the Plains causing flooding rainfall. At the time, some considered it as one of the worst floods in Oklahoma history. There was a large swath of excessive rainfall which spread from West Texas to Illinois. Some places in Oklahoma saw as much as 10 inches of rain.
While it is too early to tell what the exact track of this system will be, or just how much rain it is able to generate, it will be something to keep an eye on over the next week. It currently appears that the best chance of rain will come on Friday and Saturday.