Heavy Rain!

Southerly winds are on the increase this evening, as higher dewpoints surge northward.  This surge in moisture will help set the stage for heavy rainfall over the next couple of days.  A trough is currently over the southwest and will push eastward while slowly closing off.  This closed low will slowly move across Texas, Wednesday through Thursday.  Texoma will begin to see the impacts from this system as early as tomorrow, late afternoon.  Showers and thunderstorms will erupt as the low moves into eastern New Mexico, and as a warm front separating moist air from very moist air will moves north.  The warm front will lie across southeastern Texas tomorrow afternoon, well south of I-20.  Locations north of the warm front will see elevated thunderstorms develop with a hail threat, while locations south of the front could see large hail, damaging winds, and an isolated tornado threat. (The wind-shear near the warm front will be high!)  I'm very concerned in regards to the tornado threat; people in south Texas need to stay abreast to the threatening weather tomorrow.  Here is the latest outlook from the SPC. (The greatest tornado threat is in the yellow shaded region; the brown shaded region, north of the yellow shaded region, will likely see elevated storms with large hail.) 

Heavy rainfall will also be a threat associated with this slow moving low.  Elevated thunderstorms will likely "train" over the same locations which could cause some isolated flash flooding.  Locations east of I-35 have the best shot at seeing the heaviest rainfall; several locations east of 35 will see 3-4"+. (I would not be surprised to see some isolated 5-8" amounts!)

The aforementioned warm front will continue to move slowly north into Wednesday, and setup just west of I-35.  Elevated thunderstorms, with heavy rainfall, will continuously ignite near this frontal boundary as the low slowly treks across central Texas.  Heavy rain will be the main threat on Wednesday, but with high shear values in the warm sector, an isolated tornado/wind threat does exists; the clouds and rain will likely limit the severe potential.  The SPC has outlined an area of 5% severe probabilities on Wednesday, at this time.

In extreme west Texas, some wet snow will be possible underneath the closed low, Wednesday into Wednesday night.  The locations that can expect to see some snow will be the Big Bend part of Texas. (It's possible that parts of the Panhandle and southwest parts of Oklahoma could see a flake or two mix in, but at this time that's a very slight chance.  The strength and track of the low will be crucial in regards to the snow potential, out west.) I will include an optimistic map, in terms of snow, from the Lubbock NWS.

Right now it appears the low will weaken as it moves across Texas, thus dynamic cooling will become less of an issue, meaning snow chances will decrease with the eastward movement of the low.
We will continue to monitor this developing situation and give updates as needed.  The track/strength of this system is not set in stone some some adjustments are likely over the next 12-18 hours.  Check out the severe weather/tornado safety tips on www.primoweather.com under the severe weather tab.  A cool front will move into Oklahoma on Friday, as a short wave pivots across northern Oklahoma possibly bringing a light rain/snow mix.  More on this in the coming days.

Heavy Rainfall, Thunderstorms, Snow(West)..Followed By Cold!

The models are finally agreeing on the strong upper low that will impact Texoma, late tonight through Tuesday; the low will track between I-10 and I-20.  The main impacts will be heavy rainfall in Texoma with most locations receiving over 1".  Locations east of HWY 75, and south of the Red River, could get between 1.75-2.5".  

Southeastern parts of Texas will get the heaviest rainfall, and will also have a chance for isolated severe storms, tomorrow.  As the low tracks eastward, it will deepen over west Texas, increasing our rainfall chances, and increasing the threat for severe thunderstorms.  The main limiting factor will be instability, due to thick cloud cover and early morning showers; however, some thunderstorms that become surface based have a shot at producing damaging winds, and there's a very slim chance for an isolated tornado.  Here are the probabilities from the Storm Prediction Center.


On the backside of this deepening low, and directly underneath it, will be snowfall, some of if it heavy!  The locations that will see the heaviest snow, 4-8", are: the western Big Country, portions of the Edwards Plateau, and the Concho Valley. (Elevation will play a big role in terms of snowfall totals!) These locations will see snow starting to mix in with the rain, tomorrow and then continuing into Tuesday.  Some portions of Texoma, 50 miles west of I-35, could see some wet snow mix in with the rainfall too, no accumulations are likely. (We will continue to monitor the track, strength, and temperature profiles, in case any eastward or westward changes need to be made to the current snow line.)

The next strong cold front will blast through Texoma late Wednesday into early Thursday.  Very cold air will filter into our region behind this front.  Temperatures will likely stay in the upper 30's and lower 40's, for highs.  A few models were hinting at another southern storm moving overhead Friday, but those models have now backed off on that solution.  We will continue to monitor the latest trends because if an overrunning scenario were to develop, we could have a problem on our hands; temps would be cold enough to support winter precipitation.  

There will likely be several more cold air-masses moving into Texoma over the next few weeks due to the AO (Arctic Oscillation) going negative.  When the AO goes negative, there tends to be higher pressure over the pole regions which can penetrate cold air-masses southward, towards our region.

Another factor, which will play a role in sending cold air-masses into our region, is the stratospheric warming event that is forecast to kick into high gear in the next several days.  The warming of the stratosphere can cause a displacement of the polar vortex, which in return can send very frigid air southward. 

There are some inconsistencies in regards to air-masses moving south or southeast, and just exactly how long the air-masses will stay in place, over a particular region.  Right now I think the coldest air (prolonged event) will stay to the northeast, closer to the Ohio Valley and Great Lakes, however, that does not mean that the South will not see cold weather because we WILL.  

The weather over the next few weeks will be very interesting, unlike the last several days.  Texoma Weather will continue to monitor the pattern change and provide updates as needed.  (If there are any changes in Monday/Tuesday's system, we will update you all; this system needs to be monitored!  Deepening lows, during the winter-time, are notorious for proving several surprises for the Texoma region.) Winter is nowhere near being over!