.Short Term…(This evening through Sunday)
Issued at 225 PM EST Sat Nov 12 2022
Model soundings along with relative humidity time-height cross section show saturation below 800mb at the start of the period. Low stratus will remain over the area through the first half of the overnight before breaking up and clearing from the northwest to the southeast during the early pre-dawn hours. Vort max at the base of the upper level trough axis will be swinging through the Ohio Valley at the start of the period. When you factor this along with the aforementioned low-level moisture and stratus deck decided to carry flurries through the first half of the tonight forecast. It will be cold overnight with lows in the mid/upper 20s which is 10 degrees below normal for mid November.
High pressure currently over the Dakotas will build in over the Ohio Valley by tomorrow. Good subsidence along with increasing heights as upper ridging develops will provide mostly sunny skies. Temperatures will be warmer than today but still 10-15 degrees below normal as highs will only top out in the low 40s.
.Long Term…(Sunday night through Saturday)
Issued at 300 PM EST Sat Nov 12 2022
Sunday Night – Monday…
Cold surface high pressure will be in control to end the weekend and start the new work week. Given nearly calm winds and mostly clear skies, we should have pretty decent radiational cooling for Sunday night/Monday morning. As a result, expect low temps well into the 20, with even some upper teens possible in some of the cooler spots. Highs Monday are expected to be in the 45 to 50 degree range for most under mostly sunny skies. Outside of temperatures, expect a dry period as SW flow aloft holds over the area, but lacks deep moisture or any notable forcing features.
Monday Night – Tuesday Evening…
On Monday night, a shortwave will be quickly ejecting out of the southern Plains and then travailing up through the Ohio River Valley by Tuesday. This feature is expected to tap into a bit of Gulf of Mexico moisture ahead of arrival, which is creating some varying model solutions on just how much QPF falls, and where. Looking like a marginal thermal profile for the time period Monday night into Tuesday, however do expect to see some mixed precipitation during the overnight hours into Tuesday morning, before temps warm back more solidly above freezing. Forecast soundings do show pretty good saturation up through 600mb, with some saturation into layers colder than -10c, so also some periods of all snow are possible in areas where temps are at or near freezing.
Saturation becomes more shallow through the day on Tuesday as the deepest moisture departs with the exiting shortwave. However, low level lapse rates do look to steepen a bit, so could see a few lingering and non-impactful rain or snow showers with temps above freezing on Tuesday. Overall, the trend will be drying the later into the day and evening we get.
Tuesday Night – Saturday…
The shortwave will have exited by Tuesday evening with dry and cold conditions expected to mostly prevail. Can’t rule out a few
instances of light rain or snow showers with any individual vort lobe rotating through the mean flow during the week, however most of the activity looks to remain to the north with the parent trough. There could also be a subtropical jet impulse to keep an eye on late week, but this feature is farther south in current deterministic runs. Any phasing potential that far out can be pretty low
confidence. Will keep the forecast dry in line with previous shift for now until some of the finer details of any one disturbance become higher confidence.
Highs each day will continue to run mostly in the 40s. Meanwhile, lows each night will be in the 20s and 30. A few upper teens are possible again Friday and Saturday morning in the coolest spots.
.Aviation…(18Z TAF Issuance)
Issued at 1205 PM EST Sat Nov 12 2022
MAIN IMPACT: Lingering MVFR to IFR CIG this afternoon and evening with a return to VFR late tonight into tomorrow.
DISCUSSION: Current radar shows the wintry precipitation diminishing for SDF/LEX and ending for HNB/BWG. Expect all precipitation to be over by the start of the forecast with the exception of some light vicinity showers for LEX. Once the precipitation ends, low CIGs between IFR/MVFR will linger this afternoon and evening as the overall system continues to lift off to the northeast. Dry air associated with a sfc high currently over the Dakotas will advect in as the sfc high builds in over the Ohio Valley on Sunday. Winds will be out of the west-northwest through the forecast with clearing skies for Sunday.