KLMK issues Area Forecast Discussion (AFD) valid 2019-12-02T08:25:00Z    

870

FXUS63 KLMK 020825

AFDLMK



Area Forecast Discussion

National Weather Service Louisville KY

325 AM EST Mon Dec 2 2019



.Short Term...(Today and tonight)

Issued at 315 AM EST Mon Dec 2 2019



...Minor Snow Accumulations Possible Today...



Main weather player is a closed upper low over central Ohio, which 

will move ESE across the Virginias today. A vort lobe pinwheeling 

around the west side of this system is bringing mostly light precip 

SSE across southern Indiana and most of Kentucky during the 

overnight hours. Temperature profiles so far are marginal enough 

that precip type is mostly rate-driven, and we just haven't had the 

rates to support more than the odd rain/snow or rain/sleet mix at 

times. 



This will continue to be a marginal event through much of the day 

today. Model soundings continue to show decent low-level lapse 

rates, but through too shallow of a layer to really get into the 

dendritic growth zone (DGZ). While there is saturation at cold 

enough layers, the instability in the DGZ just doesn't support great 

snowfall rates or snow-to-liquid ratios. Air temps will remain just 

above freezing, and ground temps should remain warm enough to limit 

impacts as well.  



All that being said, there is still a window for minor snow 

accumulations through midday in the terrain south of Lexington 

toward Lake Cumberland. Expect most locations to see less than a 

half inch of snow accumulation, but the Winter Weather Advisory 

continues to reflect the best chance for localized 1 inch amounts if 

we can get a streamer off Lake Michigan. Based on collaboration with 

JKL and OHX, will shorten the expiration time to 18Z. Farther west, 

the terrain influence is less and potential for accumulating snow 

will quickly diminish once the main vort lobe pushes into Tennessee. 

Will not re-issue the Special Weather Statement for areas outside 

the advisory but can't rule out a few flurries through the day. 



If we believe the models there is a better shot at a Lake Michigan 

streamer this evening, but that has a very good chance of staying 

entirely north and east of our forecast area. Will include slight 

chance POP roughly along and east of I-75, but not get too carried 

away with it beyond that.   



Temps won't move much today, with a couple degrees left to drop 

before daybreak but only recovering to current levels for the 

afternoon highs. Only partial clearing in west-central Kentucky 

tonight, with most of the area staying cloudy, which will keep 

diurnal temp ranges small. 



.Long Term...(Tuesday through Sunday)

Issued at 310 AM EST Mon Dec 2 2019



Still expecting several dry days in the extended forecast. Tuesday 

looks partly to mostly cloudy with lingering low clouds in the 

morning and an increase in mid-level cloud cover later in the day. A 

progressive shortwave trough will rotate overhead Tuesday evening, 

but moisture depth will not be sufficient for precip. Highs are 

expected to range from the upper 30s to mid 40s. 



Upper level flow flattens out through the remainder of the work 

week, and sfc high pressure builds overhead by 12z Thu. A modest 

shortwave zips from the southern Plains across the Southeast Thu 

night into Friday and could bring light precip to the area. Will 

continue with low chance PoPs with this forecast. A strong sfc high 

builds in from the northwest on Saturday. A chance for rain returns 

by Sunday as low pressure gets organized over the Plains, but could 

see the rain holding off until Sunday night or Monday.



&&



.Aviation...(06Z TAF Issuance)

Issued at 1225 AM EST Mon Dec 2 2019



Cold rain and mainly fuel-alternate MVFR ceilings in the terminals 

initially, but colder air just upstream is still on track to change 

over to snow at times. Confidence is fairly high that we'll see 

enough IFR ceilings to justify TEMPO groups at all but BWG, while 

visibility remains more uncertain. Brief IFR vis possible in pockets 

of heavier snow, but shouldn't persist enough to mention anything 

below 3SM.  



Precip will taper just before daybreak, but fuel-alternate ceilings 

will persist for most of the day. W-NW winds with gusts near 20 kt 

should also continue, with winds diminishing and ceilings lifting to 

high-end MVFR after dark.



&&



.LMK WATCHES/WARNINGS/ADVISORIES...

IN...None.

KY...Winter Weather Advisory until 1 PM EST /noon CST/ this afternoon 

     for KYZ055>057-066-067-078-082.



&&



$$



Short Term...RAS

Long Term...EBW

Aviation...RAS