Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 241200 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 800 AM EDT Sat Mar 24 2018 .UPDATE... Issued at 800 AM EDT SAT MAR 24 2018 Precipitation making steady headway east and northeast across eastern Kentucky. Getting reports of moderate snow around Stanton and Clay City, but accumulations remain confined to grassy surfaces. Temperatures will continue to wet-bulb to right around freezing along and north of roughly a Harlan to McKee line, with precipitation transitioning to rain from south to north through the morning into this afternoon. && .SHORT TERM...(Today through Sunday) Issued at 413 AM EDT SAT MAR 24 2018 Light rain continues to push into the Lake Cumberland region this morning as a warm front lifts northeast through the mid-Mississippi Valley toward the Tennessee Valley. The parent surface low will track from eastern Kansas across the Ozarks, allowing abundant moisture to stream into eastern Kentucky. Temperatures largely remain in the upper 30s to lower 40s throughout much of eastern Kentucky, with a few locales across the Big Sandy region and far eastern Kentucky sitting in the low 30s as a result of being farther displaced from the warmer incoming air and still being under the influence of a residual cold dome on the southwestern fringes of high pressure. Dewpoints in the Bluegrass region still remain in the mid 20s, so wet bulb processes will allow for cooling temperatures this morning once virga/rainfall arrives. This should allow for a mix of rain and snow with likely all snow for a period into this afternoon from Fleming to Elliott Counties and perhaps a few points south and west. Snowfall accumulations will likely be dampened by antecedent warm ground conditions and extremely wet snow, evidenced by isothermal sounding profiles just below freezing. Stout omega profiles, especially above the boundary layer and right in the dendritic growth layer, suggest plenty of lift in tandem with forcing for ascent associated with shortwave energy stretching from the Corn Belt through the Ohio Valley. Expecting 1.25 to 1.75 inches of precipitation south of Mountain Parkway with around an inch north through tonight. River flooding concerns may arise across portions of the Cumberland River basin as elevated convection may result in periods of heavier rainfall this afternoon and evening. Snowfall amounts still look to fall in the 3.5 to 5 inch range along and north of a Mount Sterling to West Liberty line, with 1-3 inches south of this and north of a Stanton to Jackson to Whitesburg line. These will be refined through the day based on thermal profiles. It is important to keep in mind that a degree or less difference in temperature profiles could spell the difference between several inches of heavy/wet snow and cold rain. Nonetheless, even a couple of inches of snow today may be enough to produce scattered power outages. After transitioning to mostly rain this afternoon, the snow line will shift back south this evening into tonight. Precipitation will taper off from north to south as the upper shortwave trough shears out and translates across eastern Kentucky before becoming absorbed with energy across the northeastern CONUS. Surface ridging remaining centered across Quebec along with rising upper heights locally will negate a strong push of cold air into eastern Kentucky tonight as the surface low shifts south and east. This should keep ridgetops near the Virginia state line from seeing much in the way if any additional snowfall accumulations this evening and tonight as precipitation remains mostly liquid. Drier conditions will prevail Sunday afternoon with temperatures topping out in the mid 40s north to mid 50s south. .LONG TERM...(Sunday night through Friday) Issued at 453 AM EDT SAT MAR 24 2018 Upper level ridging will take hold early Monday through Tuesday, bringing drier weather into the Commonwealth. A trough will develop to the west as a surface low pressure system develops. With the progression of this low pressure, a warm front will set up over the Great Lakes into the Ohio Valley later on Tuesday. This southerly flow will usher in warmer, moist air up from the Gulf of Mexico. As the surface low continues to progress eastward, a fairly slow moving cold front will move over eastern Kentucky Thursday. This system will be the main source of precipitation for the extended period. One thing to note is that the precip for the forecast period will be all rain due to the increase in temperatures from the southerly Gulf flow. There is fairly good agreement in the upper level pattern in the models, especially early on in the forecast period. But, the GFS shows higher QPF to the west of the CWA by Wednesday morning compared to the ECMWF. The GFS QPF ranges from 0.1 to 1 inch, with higher amounts to the north and west of the CWA. The ECMWF shows QPF of 0.25 inches in the northernmost portion of the CWA at this time. The latest trends in the model runs then show the track of the system southward over the Appalachians as the upper level trough deepens and progresses eastward. The GFS track is more southerly than the ECMWF, though, since the upper level trough is more amplified. This also correlates with the higher QPF shown in the GFS run. Therefore, confidence is low for the later portion of the extended. Opted for the Blend for the most part, with little adjustments in the PoPs moreso for the later portion of the extended. Temperatures will be on the increase with the advancement of the southerly, warm Gulf air. High temps will be in the 60s for the majority of the period until the passage of the cold front later Thursday, bringing a decrease in temperatures to end the work week. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 800 AM EDT SAT MAR 24 2018 MVFR conditions unfolding across the Lake Cumberland region will continue to progress northeastward this morning. These will further lower toward IFR levels this morning as rain moves in from the west, also subsequently reducing visibilities to IFR/MVFR levels. Farther north, will see snow impact SYM, SJS, and JKL, leading to slushy/slippery tarmacs this morning and possibly into this afternoon. Should see a changeover to mostly rain this afternoon with some snow continuing to mix in along and north of an IOB to PBX line. The snow line will gradually work back south this evening and tonight as precipitation tapers off from north to south, while ceilings and visibilities remain IFR/MVFR through much of the night. Additionally, the terminals across southern to southeast Kentucky, including EKQ/SME/LOZ may see a few bolts of lightning this afternoon and evening as elevated thunderstorms will be possible. Winds off the deck will quickly veer from easterly to westerly within the lowest few thousand feet. May see speeds approach 30-40 knots at times, but have kept low level wind shear out of the forecast for now as the greatest impact from this may be just above FL020. && .JKL WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 2 AM EDT Sunday for KYZ044-050>052- 060-104-106. Winter Weather Advisory until 2 AM EDT Sunday for KYZ059-107>110- 119-120. && $$ UPDATE...GUSEMAN SHORT TERM...GUSEMAN LONG TERM...CGAL AVIATION...GUSEMAN is the U.S. government's official web portal to all federal, state and local government web resources and services.