499 FXUS63 KLMK 202325 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 625 PM EST Mon Jan 20 2020 .Short Term...(This evening through Tuesday) Issued at 221 PM EST Mon Jan 20 2020 Tonight, a shortwave, stretching west to east from Missouri to North Carolina, will continue its dive to the southeast. This takes it over southern Indiana and central Kentucky. No meaningful precipitation will result, but enough moisture will remain in the dendritic growth zone to allow flurries and very light snow to continue under any cloud cover. Around midnight, clouds will begin to move south out of the area as surface high pressure moves in from the northwest. Lows by morning drop to the mid to upper teens. Tomorrow, wake up to clear skies and a light northeast wind. Highs should make it to the mid 30s which is slightly below normal. .Long Term...(Tuesday night through Monday) Issued at 250 PM EST Mon Jan 20 2020 Tuesday Night through Wednesday Night... Fairly decent high pressure cell will pass through the region during this period. This should keep skies mostly clear at night and mostly sunny during the day. Lows Tuesday night should easily drop into the teens with highs on Wednesday warming into the 40-45 degree range. Clouds will gradually increase Wednesday afternoon and into Wednesday night with skies becoming mostly cloudy after midnight. Lows should not be as cold given the anticipated cloud cover increase and the southwesterly winds on the backside of the departing high pressure cell. Lows will range from the upper 20s over the Bluegrass region to the lower 30s over central (I-65 area) and west-central Kentucky (west of I-65). Thursday through Monday... By Thursday, we'll see heights rise along the western US coast and a downstream trough axis will be pushing into the central Plains. By late Thursday, this trough axis looks to cut off into a closed low over eastern KS/western MO. This closed low will likely then roll eastward through the Ohio Valley on Friday and into Saturday bringing widespread rainfall to our region beginning Thursday night and lasting through the day on Saturday. Still looks like we'll see a good 0.75-1.25 inches of rainfall with this system as it pushes through the region. Highs Thursday will warm into the upper 40s to the lower 50s with highs on Friday generally in the mid-upper 40s. Behind the system on Saturday, there is not a large amount of cold air as the flow behind the system remains quite zonal and the airmass is basically modified Pacific air. We'll have plenty of low clouds around and some light rain will be possible during the day with highs mainly in the upper 30s to the lower 40s. Moisture will remain entrenched Saturday night and into Sunday and with a cooling boundary layer, probably will see some snow flurries in the Saturday night and very early Sunday time frame. Highs on Sunday should be a little warmer, depending on how much clearing we see. Current suite of guidance suggests highs in the mid-upper 40s. Another quick moving wave may bring a round of showers to the region Sunday night and Monday with lows in the mid 30s and highs on Monday in the upper 40s to near 50. Beyond Monday and into Week Two... As we move into week two, there is not a whole lot of change going on at the hemispheric level. Global atmospheric angular momentum continues to run well above normal which is leading to a stronger than normal jet stream pattern across the northern hemisphere. With the flow being fast, systems coming across North America haven't really been able to amplify all that much. The stratospheric polar vortex remains very strong and displaced well away from North America. Forecast teleconnection patterns continue to strongly suggest that a +AO/+NAO/+EPO/+PNA pattern will continue and the current MJO pulse will pass through phase 6 and into phase 7 as we close out January. This pattern is a hostile pattern for cold and snow in the eastern part of the US. Thus, we expect to see temperatures run above normal during week two with normal to above normal precipitation chances. Experimental signal analysis guidance has been suggesting for the past couple of week that a strong signal could pass through the region around 1/30. The latest dynamical models are now catching on to this, but are probably a tad too fast. Given the hemispheric pattern, another windy/rainy system looks likely as we close out January and head into February. && .Aviation...(00Z TAF Issuance) Issued at 620 PM EST Mon Jan 20 2020 Borderline MVFR/VFR strato-cu in place across the area in response to an upper wave diving SE into the Tennessee Valley. Can't rule out a flurry or two this evening, especially at BWG, but not looking for any significant impacts even if it does happen. Expect ceilings to scatter out later this evening, finally clearing off around daybreak Tue. Light N winds tonight will veer to NE Tuesday morning, but should remain close to 5 kt. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Short Term...KDW Long Term...MJ Aviation...RAS