7/13/09 Forecast

Forecast Area: NE OK

Timing and storm mode:
Convection should initiate after 2PM to the NE of Tulsa on a line from Bartlesville OK to Tahlequah OK and to the south. Expect cells to initially be discreet with storm motion to the SE at around 15mph.

Synopsis:
The dominate feature at this time is a strong upper level ridge running from ND to the Mid Atlantic states. There is also a upper level high centered over central TX. Down slope winds of the rockies continue to pump heat into the region. A cold front along the OK/KS border running to the SE through central AR has been the focus of overnight convection.

Discussion:
Temperatures will hover around 100 in Tulsa today with slightly cooler temperatures to the NE due to the influence of the overnight convection and the associated cold front. Expect the front to remain relatively stationary and to slide to the east overnight. Dew points are in the 70’s across NE OK falling off into the upper 50’s across western OK due to the down slop winds and dry air aloft over western OK. The morning soundings show a 13-15 degree difference in dew point depressions from S KS across NE OK into central AR as compared to central and western OK.

Elevated dew points and daytime heating are creating CAPE values in excess of 8000 according to the 16Z run of the RUC. The RUC also depicts the cap breaking by early afternoon near western AR and eroding back across NE OK over the afternoon hours. The focus of any convection will most likely be along an outflow boundary that is visible on satellite and NWS radar at this hour.

There is relatively little shear for these storms to work with so do not expect much in the way of severe weather. Surface to 500mb cross over is close to 180 degrees in the area with the best instability, therefore it may be difficult for storms to sustain themselves. However, the best chance for severe storms will likely be over far eastern OK to central AR.

Expect storms to diminish this evening with the loss of daytime heating. Good news later this week as the upper ridge appears to break down by Wednesday evening bring NW flow and cooler temps and rain chances to the area. More on that tomorrow…