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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Monday
• 
• High: 36 °
• Low: 31 °
• Partly Cloudy

• Tuesday
• 
• High: 40 °
• Low: 31 °
• Snow

• Wednesday
• 
• High: 49 °
• Low: 40 °
• Partly Cloudy

• Thursday
• 
• High: 52 °
• Low: 32 °
• Rain

• Friday
• 
• High: 45 °
• Low: 29 °
• Partly Cloudy

area forecast discussion 
National Weather Service Louisville Kentucky 
316 am EST Monday Feb 13 2012 


Short term (today and tonight)... 
updated at 315 am EST Feb 13 2012 


..snow tonight over the north, wintry mix south... 


Main forecast challenges include determining where the most snowfall 
will occur, and how much will fall, as well as assessing the wintry 
mix over the south, and if that will need a short-lived advisory. 


High pressure overhead will skirt to the east today as an 
upper-level disturbance over the Western Plains pushes our way for 
tonight. This upper trough will weaken as it approaches, and thus, 
so will its surface low associated with it. Because of this, higher 
quantitative precipitation forecast amounts are expected west of here, namely across the 
mid-Mississippi Valley region. With dry low levels today, increasing 
moisture aloft could result in flurries over the west so have 
inserted those in late this afternoon. High temperatures will range 
from around the low/mid 30s north to around 40 south. 


Although the approaching system will weaken, the operational GFS and 
NAM indicate a swath of dissipating snow that should affect our 
southern in counties, as well as our west-central Kentucky counties. The 
models indicate a swath of roughly 1-2 inches of snow across our far 
northwestern cwa, also supported by the new HPC guidance. Further 
south as the system approaches, snow will be the precip type at 
onset. However, warmer air above the surface will help push 
low-level temperatures up after midnight tonight over the south, 
changing any light snow over to a mix with sleet and eventually to 
rain. So although the higher amounts of snow will occur over in 
counties west of I-65, snow will occur as far south as TN, and that 
mixing in with sleet could cause brief travel problems, as well. 
Thus, will issue a Winter Weather Advisory for all of southern in, 
and Meade, Breck, Hancock and Ohio counties in Kentucky for the snow/sleet 
mix expected. This advisory is further south because of the mix, but 
it is mainly for the snow over the northwest County Warning Area. 


Moisture decreases aloft fast as the system weakens on approach. 
This plus the increasing temps between 800 and 900mb will help 
change precip over to sleet and possibly plain rain over the far 
southwest around dawn Tuesday over the south. Because of the fast 
exiting moisture, not sure how far to extend advisory, so just have 
a first/best guess for snowfall amounts/minor wintry mix thru 12z 
Tuesday. Elsewhere overnight, light snow will overspread the 
northern half of the County Warning Area after midnight from west to east; same with 
the wintry mix over the south (overspreading after midnight from 
west to east). However, with the deep moisture exiting, quantitative precipitation forecast amounts 
generally east of I-65 should be less so will continue the Special 
Weather Statement for the remainder of the County Warning Area. Overnight lows will 
drop into the low 30s, with the coldest temps northwest. 


Long term (tuesday through sunday)... 
updated at 310 am EST Feb 13 2012 


The precipitation from the system moving through Monday night will 
continue into Tuesday. The day will start out with a mix of 
precip across the region. The Bluegrass and portions of 
southern Indiana look to be all snow to start out with, while the 
rest of north central Kentucky may be a mix of rain and snow. Further 
south, some sleet may mix in with the rain. Through the morning 
hours the atmosphere will warm. As this happens, frozen 
precipitation will change over to a mix of rain and snow, eventually 
becoming all rain by the afternoon hours as the precip is moving 
out. Temperatures will rise into the low 40s by the afternoon. This 
should facilitate melting of any snow accumulations from the 
overnight hours. However, any leftover moisture may refreeze 
overnight Tuesday night as temperatures dip to at or just below 
freezing. 


Tuesday night and the first half of Wednesday the area will see a 
break in precipitation. This will be short lived as a low pressure 
system organizes over the plains. This low will track across 
Illinois and into the Great Lakes through Thursday, dragging a cold 
front through on Thursday. Rain will begin to move into west central 
Kentucky on Wednesday afternoon and spread across the forecast area 
through the overnight period. The models are in good agreement in 
widespread rain across the area overnight Wednesday night so have 
bumped up pops during this time frame. With the low going to the 
north of the forecast area, we should remain warmer with this system 
and the precipitation should fall as all rain. Soundings show no 
instability and this system will mainly roll through during the 
overnight hours, so do not think we will see much in the way of any 
thunderstorms. Rain will move out Thursday with high pressure 
building in behind the front. 


Friday through Sunday looks to be mainly dry. A quick moving 
shortwave may bring some very light precip during this time frame. 
However, with timing and amount of moisture uncertain, will keep the 
forecast dry for now. Temperatures will be just at to slightly above 
normal through the extended period. Highs will range from the mid 
40s to lower 50s. Lows will be in the upper 20s to lower 30s. 


&& 


Aviation (06z taf issuance)... 
updated at 1153 PM EST Feb 12 2012 


High pressure centered over western Tennessee at this time, with a 
ridge axis across the border with central Kentucky. Thus winds are 
light and variable at this time with clear skies. During the day 
Monday, expect increasing mid/high clouds as a large upper trough 
moves out of The Rockies toward the region. Cigs will drop steadily 
into the evening hours, and we may see some light snow fall at kbwg 
and ksdf just after sunset. Still do not expect flight restrictions 
until after midnight for any site, which only shows up at this point 
in the 30-hr ksdf taf. Outside of light and variable winds early 
this morning, expect a more southerly component to the winds as the 
high shifts east of our longitude Monday. 


&& 


Lmk watches/warnings/advisories... 
in...Winter Weather Advisory from 7 PM EST /6 PM CST/ this evening to 
7 am EST /6 am CST/ Tuesday for inz076>079-083-084-089>092. 


Kentucky...Winter Weather Advisory from 7 PM EST /6 PM CST/ this evening to 
7 am EST /6 am CST/ Tuesday for kyz023>026. 


$$ 




Short term.......al 
long term........eer 
aviation.........Al