UPDATE: Fri 2 April 2010 / 3p.m.
Well...we lucked out; the more stable air came in (as discussed below) and the severe weather threat has ended for all of Texoma.
Drier air continues to flow eastward, making for a comfortable evening ahead.
Have a great weekend...I will post a new blog about next week's weather later this evening.
UPDATE: Thu 1 April 2010 / 3:10p.m
A threat of severe storms comes into play during the afternoon Friday, but there is considerable uncertainty as to whether these storms will form or not.
For one thing, the moisture layer is only about 5,000 feet deep. There are some indications a southwesterly wind will develop by late morning, shunting the severe storm probability into the easternmost portions of Texoma (east of Highway 75). This would leave the majority of the area just warm and windy as we headed into the afternoon. There's also a very strong "cap" at about 5,000 feet; it remains questionable whether the trough axis will reach far enough southward to erode this feature.
However, with a deep upper trough moving by a bit later (map below), pressure falls to our west could slow the wind shift and provide a dry line/cold front boundary to help fire rough storms in the afternoon. So this type of situation will require frequent updates right through tomorrow as it evolves. (original discussion below map)
The above map shows a deep trough impacting Texoma weather Friday with potential for severe storms.
Severe weather season usually kicks in by mid-March, but this year has been very tranquil with about 30% of “normal” March tornado activity nationwide. A scant 28 twisters were reported in the USA in March.
Texas reported no tornadoes in March while Oklahoma reported just two. These figures reflect the overall “peaceful” early spring season so far. Of course this is largely due to repeated intrusions of cold air which sweep out Gulf moisture and minimize thunderstorm potential.
However, there’s the potential for some heavy rain and possibly severe weather as an upper trough moves our way Friday. Strong southerly winds are expected to blow for several days ahead of the trough’s arrival. This increases the likelihood of ample moisture returning to fuel thunderstorms.
It’s a complicated scenario since the overall moisture profile will still be somewhat limited by southwesterly winds a few thousand feet above the surface (orange arrows over Texas on map).
There are four factors to monitor for severe potential:
1) The path of the trough (blue "L" on map) and jet
2) Timing of its closest passage to Texoma
3) Depth and intensity of wind shear
4) Available moisture
At this point, heavy rainfall appears most likely with some potential for severe storms if the trough arrives during peak daytime heating. This would most likely be a squall line with winds or hail, but it’s just too early to say.