STATUS: IOP on 12-14 March

We will commence the first IOP of VORTEX-SE Saturday, 12 March.  Observations will ramp up during the day, with boundary layer evolution observations underway by evening.  We are anticipating the passage of two marginal systems during the weekend and Monday, the first on early Sunday morning associated with the remnants of the current deep system over Texas, and the second associated with a sharp mid-level wave on Monday morning.  Potentially, we may stay through Wednesday to observe convection associated with a cold front passage.  Thereafter, long-range guidance is hinting at a quieter pattern through the end of the month.

STATUS:  IOP watch for 13 March and beyond (IOP has been cancelled for 12 March)

The consensus decision today is to not attempt to observe on 12 March because it the forecasted low-level shear is at the low end of the tornado climatology.  Forecasted MUCAPE spans a range from 0 to ~1000, depending on the forecast model.

Another strong vorticity maximum approaches the region on Sunday, and we are now beginning to watch this feature, and watching how the overall pattern evolves beyond Sunday.

STATUS: IOP Watch

We continue to watch the forecast evolution of the lifting/weakening cutoff that will become a negative tilt shortwave late this week in the south, crossing AL early in the weekend.  At this time, the forecast is for negligible chances for tornadoes with this system, primarily because of muddled and weak low-level wind profiles.  We are monitoring to determine if there might be a short window of somewhat more favorable conditions.  If so, studying the evolution of CAPE and shear in this scenario might be scientifically valuable.

Following the Friday/Saturday event, another fairly strong shortwave should pass near or north of AL on the 14th; the development of adequate CAPE remains uncertain.

A final IOP decision will be made in briefing tomorrow, Tue 8 March.

IOP Watch

We continue to watch for a short window of opportunity sometime toward next weekend, when an upper low weakens and lifts northeast from TX.  There is a chance that a weak warm front will exist near the observing area, with light east-southeast winds beneath strong southerly flow aloft, leading to sufficient low-level shear for tornadoes.  An IOP decision is anticipated around Tuesday.

The remainder of March appears to offer additional deployment chances, but the forecast uncertainty continues to be very large.

IOP Watch

We are continuing to watch the system that will cut off in south Texas early in the week.  It appears it will weaken and lift northeast as a negatively-tilted wave, with possible favorable shear in the Thur-Fri time frame.  Right now, the flow is forecast to be unidirectional, but details may change in the coming days.

We anticipate an IOP decision around Monday.

There may be two back-to-back IOPs in mid-March… one for the lifting trough, and a second one for a more promising looking system a few days later.

Sat 27 Feb 2016

Status:  IOP Watch  for possible IOP commencing Thur 3 March

As expected yesterday, the PI’s have agreed to cancel the IOP watch for Tuesday because this system appears to be too marginal in terms of low-level shear and CAPE.

The PI’s decided to commence a new IOP watch for Thursday.  Details are murky concerning the track and intensity of this wave, with a consequent murkiness in expectations concerning the warm sector location and CAPE.

Investigators who will be northern AL for other reasons are encouraged to communicate about possible informal “shake-down” deployments between now and Thursday, especially with the expected marginal convection on Tue afternoon/evening.