Issued at 940 AM EST Thu Nov 17 2022
Low clouds continue to blanket southern Indiana and most of central Kentucky this morning. These clouds should gradually erode from south to north late this afternoon or evening. Temps will be limited to the upper 30s to lower 40s for highs today.
.Short Term…(Today and tonight)
Issued at 234 AM EST Wed Nov 16 2022
IR satellite reveals abundant stratus across much of the Midwest and Ohio Valley this morning. This stratus and low-level moisture is being handled poorly by most model guidance, particuarly the southward extent of the stratus shield. AMDAR soundings reveal the depth of this stratus to be quite shallow, on the order of ~1000ft or so. Regional radars reveal no precip echoes associated with the stratus, which makes sense given the shallow moisture depth and drier low-level air that is in place near the surface.
Confidence in how long the stratus persists and how far south it surges remains low, but given recent satellite trends and low-level RH trajectories, it seems likely that it will remain over the region through the morning hours. It may not be until the afternoon that we begin to see substantial breaks in the clouds, particuarly in the southern half of the CWA. Unlike yesterday which featured light precipitation, we should remain dry today given the very shallow moisture depth in place near the top of the PBL. Have dropped temperatures a degree or two for highs compared to yesterday’s forecast given that clouds will likely persist for a good portion of the day and keep diurnal temp swings to a minimum.
A cold front will begin approaching from the northwest overnight and likely push into the region during the early morning hours tomorrow. Some models indicate we could see a narrow band of light snow flurries or showers develop ahead of the front. In this type of environment, can’t rule out some isolated snow showers dropping a quick dusting of snow ahead of the front.
.Long Term…(Friday through Wednesday)
Issued at 250 AM EST Thu Nov 17 2022
Friday – Sunday…
An amplified upper-level pattern will be in place to start the extended period with a large trough entrenched across the eastern two-thirds of the CONUS while ridging extends along the eastern Pacific into western Canada and Alaska. At the surface, a NE-SW oriented cold front associated with a low pressure system over southern Ontario will be pushing through east-central and south- central KY. Hi-res model soundings indicate we may have enough moisture and lift ahead of the front for some isolated snow showers during the morning hours, and some brief accumulations on roadways may be possible.
In the wake of the front, temperatures well below normals will prevail for the weekend with a reinforcing cold front Saturday evening helping to plunge temperatures even lower. Afternoon highs Friday – Sunday will be in the mid 30s to lower 40s while overnight lows Fri Night – Sun Night will be in the mid teens to lower 20s, with Saturday night expected to be the coldest of the period.
Monday and Beyond…
Moving into the next week, the upper-level pattern will relax a bit as the trough lifts northeast and we transition to more of a quasi- zonal flow. Surface high pressure will drift off to the east and temperatures will rebound back towards climatological normals, gradually warming through midweek. High temperatures will generally be in the upper 40s to mid 50s each day with low temperatures initially in the upper 20s to lower 30s Monday night then warming into the upper 30s to mid 40s by Wednesday night. Continue to see variability in models regarding our next chance of precipitation but latest 00Z guidance indicates that it may not be until the Thursday or Friday time frame.
.Aviation…(12Z TAF Issuance)
Issued at 601 AM EST Thu Nov 17 2022
Widespread low-end VFR to high-end MVFR stratus/cigs currently impacts much of the region this morning. IR satellite reveals some breaks in the stratus deck have occurred, but these may fill in again through the morning as low level moisture remains trapped under a modest inversion. It may not be until early afternoon that we begin to see more significant breaks in the stratus develop and it eventually scour out.
Overnight, a cold front will approach from the west and begin moving into the region toward dawn. Light snow flurries or showers may develop ahead of the front and briefly reduce cigs/vis. PROB30s have been included in TAF for HNB/SDF to account for this potential.