A Slight Risk For Severe Thunderstorms Will Exist During The Overnight-Predawn Of Saturday – Strong Damaging Winds & Hail Will Be The Primary Threats
Overnight Into Mid-Morning Saturday
Showers & thunderstorms developing. Some storms may be strong to locally severe. Downpours likely. S-SW winds 10-20 mph, with higher gusts, shifting W by morning. Temps in the 50s and 60s during the early overnight ( 40s in colder mountain valleys will be rising ) dropping into the 30s and 40s into morning ( coldest at highest elevations ).
Becoming partly cloudy. Much cooler. W-WNW winds 10-20 mph, with higher gusts. Temperatures falling into the 30s to lower 40s by sunset at lower-middle elevations and into the 20s at highest elevations. Wind chills plunging into the 20s & 30s, except into 10s at highest elevations, by late PM.
Saturday Night Into Sunday Morning
Mostly clear. Cold. WNW winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges-plateaus. Temperatures varying from mid-upper 10s to mid-upper 20s. Wind chills in the single digits and 10s along gusty mountain ridges ( near 0 degrees highest elevations ).
Mostly sunny. Seasonably chilly. Light & variable winds. Temps varying from low-mid 30s at highest elevations to the mid-upper 40s.
Sunday Night Into Monday Morning
Increasing high clouds. SSE-S winds 5-15 mph, with higher gusts, on mountain ridges below 2700 feet. SSW-SW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet. Temperatures varying from 20s to lower 30s in colder valleys to readings steady or rising into upper 30s to middle 40s along gusty mountain ridges.
Weather Discussion ( Up And Down )
A squall line or broken line of strong to potentially severe thunderstorms will rumble into the mountains during the overnight-predawn hours of Saturday.
Typically, in February, weakening would be most likely and while it may still occur…due to a strong temp gradient and wind fields this can not be counted on and everyone should remain alert to NOAA Weather Radio and your favorite media sources for possible watches-warnings.
A very strong temperature gradient, with 850 MB readings at 11:00 PM Friday varying from +8 Celsius ( 46 degrees F ) over western Kentucky to -8 Celsius ( 18 degrees F ) across western Illinois, has developed along and behind a band of showers and strong-severe thunderstorms ( below ).
Midnight temperatures on the Kentucky Mesonet as high as 72 degrees in Booneville of Owsley County are in contrast to middle 40s in far western Kentucky ( midnight temps in the 40s are also occurring in local mountain valleys which will result in a crazy rise into the predawn followed by a strong drop after sunrise into mid-morning behind the storms ).
Strong temperature rises are likely in local mountain valleys as turbulent mixing increases ahead of the squall line and cold front to recouple them with strong boundary layer winds ( i.e., valleys with calm winds currently will turn gusty with strong temp rises ).
Despite the mildness of February 2017, and spring sights, a colder pattern is looking to return for perhaps a longer stay than just this weekend. Warming into the middle of next week will be followed by colder conditions as March begins.
Upper air troughing into the eastern USA, and late season cross-polar flow, is currently being predicted to develop during early March ( above ) to produce temperatures that are colder than average ( below ).
So as most everyone knows, it is far too soon to even think about planting anything tender. Native vegetation which is beginning to bloom will not be hurt as severely as cultivated or non-native species not acclimatized to such conditions.