Squall line moving east

– The SPC has upgraded most regions across southeast KY to a moderate risk for severe storms

– this line should strengthen throughout the day

– Reports of hail, gusty winds and a tornado in madisonville have already been recived by the NWS

– The storms just east of madisonville still have week rotation

– ANY storm can produce a tornado quick as helicity values in some areas are over 700 m/s^2

– Gusty winds just east of the Louisville metro now.

– I have concerns this will be a long day for southeast KY with widespread wind damage a few hail reports and a few tornadoes as well.

 

Short term update

-squall line starting to advance on I-65. Storm near madisonville,KY will move toward Mammoth cave and has strong rotation and a hail core. Other storms in the line may produce gusty winds.

Wednesday threat focused south and east

A warm front is still expected to move through overnight. A strong Low level jet (LLJ) will transport moisture into the boundary and provide the lift needed for a period of showers and storms in addition to keeping temperatures rather steady around 60 overnight. Southerly winds will increase as well. Along this warm front, shear will be more than sufficient for severe weather. The majority of this activity I expect to be elevated with means just heavy rain and thunder.  However due to the large amount of shear any isolated storm which does become surface based overnight may produce a tornado.

The question is can enough instability materialize for some severe storms Wednesday afternoon with the cold front?

Wednesday afternoon the cold front moves through and will likely develop another round of showers and storms. With daytime heating and a continued transport of warm unstable air into the region I do think at least marginal instability should be present across the region. By early afternoon though the front could very well be closing in on I-65. The best lift for storm development is just ahead of the front making the most likely regions for round 2 Wednesday afternoon further southeast. Storms will have a damaging wind/ isolated tornado threat through the afternoon and early evening. Regions ahead of the front should see a temp spike into the 70’s as well.  I’ll update any warnings overnight tonight as needed. tomorrow morning we’ll use the RUC and HRRR to actually see where the front will be in the afternoon and pinpoint the exact regions that will see storms.

Modeled rainfall on the GFS is overdone due to convective feedback in my view. The NAM, EC and SREF are much less than the 12z OP GFS. Overall rainfall should be from 1/2 to 1 inch perhaps some slightly higher totals in storms.

Friday threat looks more favorable for timing across the region. I’m suspecting another squall line event in fact instabilty may be a touch more than this Wednesday event. Still I also feel either Sunday or Monday we’ll be stuck with 30’s/40’s for highs and a rain/snow mix. I’m seeing other forecasts back off of 60 and sunny for this time frame.

 

Severe threats this week still forecasted

Just want to update the highlights the forecast is on the last post

1. Rounds of showers and storms are likely Tuesday night and Wednesday. Enough instability may move into the region coupled with a high shear enviroment for a squall line of severe storms Wednesday afternoon with the highest chance southeast.

2. Another squall line thunderstorm event is likely Friday night with a severe threat.

3. I see many forecasts near 60 for highs Monday and sunny skies not so fast folks! The CMC and EC dig a trough in the region. Thickness values fall well below 540 coupled with 850 mb temps from -5 to -10*C. precipitation as well. I think a mix of rain and snow showers with most of us in the upper 30’s to mid  40’s for highs. We’ll see how this plays out for now We’ll do an old fashioned forecasting war.

 

BG day 7 Monday

NWS LMK- 57

Me-47

A tie would 52 for a high.

Severe threats this week

1. After starting out in the mid 30’s to low 40’s temperatures should rebound into the low and mid 60’s for highs. Will trend above guidance with temps. A mix of sun and clouds should also be present with a southwest wind of 5-10 mph.

2. Tuesday the southerly winds should increase perhaps on the order of 10-20 mph. Cloud cover will also increase ahead of a  warm frontal boundary. An advection of some instability and moisture should occur but mainly Wednesday. The threat for severe weather Tuesday night looks very similar to last thursday, marginal. Showers will be likely with a few thunderstorms. Storms may have gusty winds. Any increase in the modeled instability may bring a severe threat into the mix, however this appears unlikely at this time for Tuesday night. Timing is not favorable for severe weather being after midnight Tuesday night for the highest rain chances. The system passing well north of the region on Monday should be culprit in the limited northward advection of moisture and in fact may send in some low level cold air keeping lows in the 30’s Tuesday. Highs should reach the 60’s in most spots perhaps a few 50’s north with the warm frontal passage.

3. A strong LLJ will keep temperatures in the 50’s Tuesday night. The  cold frontal boundary will be slow to cross the region. I suspect a temperature spike occurs ahead of the boundary with continued strong southerly winds. Highs should top 70 in many regions. Along the cold front I suspect enough shear and instability will be present for another round of showers and storms this time with a severe threat. Damaging winds and isolated tornadoes would be the main threats focused on southeast KY. Any changes in timing could alter the high temp and instability advection into the region Wednesday.

4. Don’t expect much of a cooldown behind the front. A mostly sunny day should occur with lows in the 40’s and highs in the 60’s. The next severe threat with another front moves into the region Fri/Sat.