Alan Crone's Weather Blog: Severe Weather Threat This Weekend

Friday, May 8th 2015, 4:31 am
By: Alan Crone

We're tracking a powerful upper level system that will bring severe weather threats to the state today and this weekend, including the potential for large hail, damaging winds, flooding rainfall and tornadoes.  A flash flood watch is now posted for a large portion of eastern OK due to recent rainfall.   Model output suggestions combined with observational data support 3 to 6 additional inches of rainfall will be possible for some locations before the main upper level system exits the area Sunday evening.   

Weather Alert Information

 The main upper level low will be exiting the area late Sunday night with improving and mild weather conditions for Monday and Tuesday.   More storm chances could arrive late next week.  Temperatures this morning remain in the 60s along with variable winds around 10 mph.   Changes to this forecast and forecast discussion are still possible regarding the weather today through the weekend.  

Storms developed yesterday to the west and moved eastward during the evening hours into eastern OK.   These storms have already exited the region this morning.   Some patchy fog will be possible for a few hours near or west of the metro where clouds are attempting to temporarily thin out.  There's a slight chance of a few showers or storms attempting to redevelop this morning in a few spots to our southwest, but the chance is low.  The main focus for eastern OK will be later this afternoon and tonight.

While numerous computer weather model suggestions depict the potential for severe weather across the region during the next 48 hours or so, the overall discussion this morning is being produced by observations and pattern recognition.       This recognition supports the potential for a regional severe weather outbreak Saturday, especially across western and central OK.   The potential for severe weather also extends eastward into portions of eastern OK both today and Saturday, but to a lesser extent compared to western and central OK.  

This morning certain Hi-Res model runs have thrown some questions into the equation regarding today's scenario.  

Observations and early model runs indicate storms may develop early today across part of the High plains of Texas and spread into southwestern OK around noon.   This early initiation may hinder some of the severe weather potential for portions of the region, but conditions will still be favorable for some severe storm activity today.   This early timing would place some storm activity approaching the eastern portions of the state by 3pm.   This is much earlier than depicted in some earlier model runs.   Storm chances will remain in the forecast for this afternoon into the evening hours.   Some overnight storms may exist, but if the early start timing verifies for today, the first batch of storms could be exiting the region quickly this evening.   We will plan for some storms lingering into pre-dawn Saturday across extreme eastern OK at this point. 

WARN Interactive Radar

Saturday afternoon the main upper level system over the Rockies begins moving eastward.   A strong surface area of low pressure will develop and intensify over southeastern Colorado with a dry line extending southward across far western OK.   Storms are expected to rapidly develop Saturday midday to early afternoon ahead of the dry line and move east to northeast.   Severe weather parameters support the potential for all modes of severe weather including a tornado threat.   Extremely large hail and torrential rainfall will also be possible with super cellular thunderstorms Saturday afternoon and early evening.   Locations across central and eastern OK Saturday afternoon could also see storms developing ahead of the dry line, but the higher chance during the early portion of the event should remain across the western third of the state.   Storm chances will remain Saturday afternoon into the late evening hours across the central and eastern sections of the state with a continued severe weather threat.   Overnight storms into pre-dawn Sunday morning could retain some diminished severe characteristics as they progress into western Arkansas.   Additionally the threat of heavy rainfall resulting in a continued flooding threat will remain.  

Sunday mid-morning to early afternoon the main upper level system begins ejecting into the central Kansas and will move into the Dakotas by evening.   The surface low will move northeast and cold front will overtake the dry line by early afternoon as it enters northeastern and eastern OK.   Storms are likely to develop along this boundary and become severe with large hail, damaging winds and flooding rainfall the highest concern.  Dry and stable air finally moves into the area sometime late Sunday night or pre-dawn Monday bringing an end to this multi-day severe weather threat.    

As always, I encourage you to remain aware of your weather surroundings during the spring months.    More so for the next 48 hours as this major storm system begins to influence the central and southern plains.   

Thanks for reading the Friday morning weather discussion and blog.  

Have a safe weekend. 

Alan Crone