Wednesday, October 17, 2012

Showers and storms set to impact the area tonight....

Warmer conditions have flooded much of the region for the past couple of days as highs have gradually warmed into the low to mid 70's across the area.  Mostly sunny conditions have ruled the skies for Wednesday as those fall time colors have begin to really show across the area.  We wrapped up the weekend on a wet and windy note as a system worked its way though the region bringing showers and very windy conditions.  The front eventually tracked its way through the state and pushed eastward as a ridge of high pressure begin to build over Central Plains and into the Ohio Valley by Monday.  In return, pleasant and cooler conditions returned to the Bluegrass to kick off the week. 
We now turn our attention towards a similar set up that we had this past Sunday.  The 250 mb heights and winds map shows an upper level cut-off trough slowly tracking eastward over the Dakota's.  Jet streaks have been very strong with upper level winds reaching 100-120 knots over parts of the Central Plains as the trough continues to dig.    
250 mb Heights and Winds map valid for 06Z Thursday.
The trough will continue its progression eastward and in return drape a cold front from parts of Minnesota down into Missouri and Oklahoma.  Similar to the last set up we had on Sunday, the lack of instability seems to be the main problem with the development of widespread severe storms.  Surface-500 mb bulk shear map shows strong mid-level winds over the Central Plains ranging from 50-80 knots.  At 700mb the atmosphere continues to show a saturated upper level which is important for the development of these showers and storms.  Surface dewpoints lack a bit but range from 50-60 degrees as precipitable water values range from 1.1-1.5 inches over parts of western and south-central KY.  The SPC's latest outlook outlines the possibility for severe weather over parts of the Central Plains as those areas are under a SLIGHT risk for severe storms this evening.  The risk also includes far Western Ky counties as well as the line of showers and storms could potentially affect those areas as the front continues to slide eastward.  

SPC's latest outlook map showing a SLIGHT risk for severe weather.
Storms that do develop over parts of Missouri, Arkansas, and Louisiana will develop and track eastward ahead of the front. With the lack of instability over our area, the storms are expected to weaken considerably as they approach lesser amounts of instability.  Nonetheless, given the strong wind fields aloft, some of the convection overnight could pose a wind threat as these storms may be able to transfer some of that higher momentum air down to the surface.  These storms will have a decent amount of moisture to work with as QPF amounts range from 0.5-1.0 inches for the area.  In addition to the showers and storms, the pressure gradient will tighten up over the region bringing south to southwest winds across the area around 15-25 mph with gust up to 35-40 mph. The latest HPC forecast gives a good idea of precipitation amounts expected. 
Latest HPC map showing widespread rainfall amounts across the area.
As the system tracks through the Ohio Valley region later tonight, expect mainly windy conditions with light to moderate rain over the area.  Expect lows to drop down in the low 50's under cloudy skies as the chance for showers will loom later tonight and into your Thursday morning.  Look for partly cloudy skies across the area with highs struggling to hit the mid 60's.  Clouds look to hang tough heading into Thursday evening as lows drop into the low to mid 40's with light winds from the south.  By Friday, look for dry conditions to prevail as partly sunny skies are expected.  Highs will be a tad cooler as temperatures struggle to reach the mid 60's with winds from the southwest around 10-20 mph.

Forecaster: Chris Johnson

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.