594 FXUS63 KJKL 151825 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 125 PM EST Sat Feb 15 2020 .UPDATE... Issued at 125 PM EST SAT FEB 15 2020 Temperatures are warming a little bit less than was forecast so far today, and the max T forecast has been shaved back slightly. UPDATE Issued at 1118 AM EST SAT FEB 15 2020 Forecast was in overall good shape. The morning obs have been blended into the gridded forecast data. UPDATE Issued at 656 AM EST SAT FEB 15 2020 Temperatures have fallen to around 10 in many valley locations this morning, making for a cold start to the day. Temperatures should rebound quickly upon sunrise this morning. No changes needed at this time. && .SHORT TERM...(Today through Sunday) Issued at 318 AM EST SAT FEB 15 2020 A surface ridge extends from New York southward into east Kentucky this morning with clear skies and calm winds dominating the region. These conditions have allowed temperatures to dip into the low to mid teens this morning. Temperatures will bottom out around 10 in the next few hours in the colder valley locations. A full day of sunshine is expected today as the surface ridge slowly drifts east and we start to see some light southerly winds develop. The sunshine and moderating airmass will allow temperatures to climb into the mid to upper 40s, with some readings around 50 possible. Mostly clear skies will continue into tonight with a modest ridge/valley split developing overnight. COOP MOS has several locations down into the upper teens tonight. Hesitant to go that low given the increasing mid/high clouds, but it does seem reasonable some of the eastern valleys could reach the low to mid 20s. Ridgetops should stay in the 30s. A surface trough will push east across the area on Sunday with a mid level vort max pushing east across Kentucky. The system will be moisture starved initially as dewpoints will struggle to recover into Sunday morning. However, dewpoints are expected to climb into the afternoon hours with a modest surge of omega pushing across the area with the mid level wave. This should help to develop precipitation which in turn will moisten up the surface. While rainfall amounts are not expected to be that high, we have seen good model agreement this morning showing goo saturation up into the ice growth region. Thus, confidence if fairly high at seeing some light rain developing by mid to late afternoon, likely continuing into the early evening hours. Have bumped rain chances up to high chance/likely category given the better model agreement. .LONG TERM...(Sunday night through Friday) Issued at 420 AM EST SAT FEB 15 2020 The period is expected to begin with a broad trough/somewhat zonal pattern with several shortwaves moving through the flow. An initial shortwave trough is expected to be moving across the area to begin the period. A sfc trough is also expected to reside from northern TN into the Appalachians early on Sunday evening. A shortwave trough moving through Ontario and the Great Lakes and into Quebec should send a cold front south of the Great Lakes and into the OH Valley and central Appalachians on Sunday night. From Monday into Tuesday the pattern should amplify a bit with some interaction and possible phasing of shortwaves moving from the Northern Plains toward the Great Lakes and a shortwave rotating around an upper level low in the Hudson Bay vicinity. As this occurs a sfc low initially over the Plains should deepen a bit and track into the Great Lakes on Monday night and then across Ontario and into Quebec on Tuesday. The boundary that will have dropped into the OH Valley on Monday, meanwhile should lift north of the area with the cold front associated with the low tracking into the Great Lakes entering the OH Valley on Monday night. This cold front should drop south and east of eastern KY by Tuesday evening. This front will have some decent moisture to work with with PW expected to climb into the 1 to 1.2 inch range near the boundary. However, this boundary should be more progressive than recent systems and rainfall is expected to generally average near a half of an inch to as much as three quarters of an inch. The operational GFS is wetter in the JKL vicinity than most of the GEFS members and appears to be an outlier. Another shortwave trough axis should move across the OH Valley on Tuesday night with another shortwave trough moving east and across the OH Valley on Wednesday night and early on Thursday. Height rises should follow across the OH Valley for Thu night and into Friday. Sfc high pressure will build into the OH Valley during this time as well and usher in a colder and drier airmass. 850 mb temperatures should briefly bottom out in or near the -10C to -15C range Thu afternoon and evening as the shortwave trough departs. 850 mb temperatures should then moderate toward 0C through the end of the period. Some patchy light rain or scattered showers should linger for a while into Sunday evening, but drier weather should follow in between systems for the bulk of Sunday night and Monday. Rain should spread south and east across eastern KY as the shortwave trough and cold front approach. Initial downslope component to the flow should lead to a later arrival in the southeast counties or cut into the QPF initially. Rain is appearing like a certainty on Tuesday and pops around 90 percent were used though trends point toward a 100 pop event in later cycles. Slight chance to chance pops were lingered into Wednesday with the additional shortwave or two upstream. The end of the period appears to be dry at this time. Temperatures to begin the period will be on the mild side and above normal. However, colder air will arrive behind the front with temperatures a few degrees below normal by Wed night and especially on Thu. Thu night appears to be the coldest night of the extended and some teens appear probable for valley locations with high pressure passing across the area and a dry airmass in place. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) ISSUED AT 125 PM EST SAT FEB 15 2020 VFR conditions and winds generally less than 10 kts will last through the period. A ceiling mostly in the 7-12K ft range will arrive overnight and persist on Sunday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL/KAS SHORT TERM...KAS LONG TERM...JP AVIATION...HAL