Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 161916 AAC AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 216 PM EST Mon Jan 16 2017 .UPDATE...
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Issued at 200 PM EST MON JAN 16 2017 Hourly weather grids have been freshened up based on recent satellite and observation trends. The warm front continues to lift northeast across the area and temperatures have climbed into the 60s in many locations and into the upper 60s in some locations. Some showers should encroach on the region shortly after sunset. UPDATE Issued at 1120 AM EST MON JAN 16 2017 Hourly grids were updated for the lingering fog on some of the eastern ridgetops and to account for the light showers that are moving through Northeast KY and into the Big Sandy Region. Current satellite imagery shows an area of clearing over northern and central parts of the area in which some locations are experiencing their first sunshine in several days as the area has been in the proximity of the frontal zone since late last week. This area is not that large and should be short lived in any given location as those areas likely will fill in with cumulus or more mid and high clouds will move back in on southwest flow. The warm front is lifting north across the area and many locations should reach the 60s this afternoon. Hourly grids were also updated based on recent observations. UPDATE Issued at 553 AM EST MON JAN 16 2017 The fog has been fairly erratic and therefore did keep the SPS going given the uncertainty in the valley locales. Some of the sites to the south have already seen wholesale improvements and would think this will be the story through the morning. No major changes needed this update.
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&& .SHORT TERM...(Today through Tuesday) Issued at 330 AM EST MON JAN 16 2017 Surface analysis shows high pressure has moved east and is parked along the Mid Atlantic Coast this morning. That said, the winds are generally out of the northeast and east this hour. The fog is fairly sporadic this morning. therefore do not see a need for a NPW this morning, but will keep the SPS going at this point. Today the quasi stationary front is expected to lift north through the day and bring unseasonably warm air mass into the region. Temperatures are expected to climb into the mid and upper 60s in near the TN border and this will lead to near record high temperatures. Also some of the short term guidance and even the lower resolution guidance would suggest showers form near the warm front. Therefore kept some mostly isolated POPs nearer the boundary. Tonight all eyes toward low pressure across Central Oklahoma this morning. There is good agreement on this vertically stacked system ejecting into the Upper Midwest through the night. A trialing cold front will slowly press east along with jet energy. The first part of this will be upper level jet dynamics punch into the region, as left exit region comes through the Ohio Valley leading to divergence aloft. This will induce a moderate 850mb jet approaching 60 knots by early Tuesday morning. These elements will lead to deep layer moderate to strong omega seen in the time heights, as mid to upper level short waves ride the flow into the region. Therefore could not argue with CAT POPs as we move toward dawn hours on Tuesday morning. Right now best axis of precip is lining up in areas generally along and north of the Hal Rogers Parkway. Overall amounts will be around a quarter to three tenths of an inch through the morning. That said, the dynamics are such that a few rumbles of thunder would be possible and this lines up with best MUCAPE and SPC. Now this is a two part system as the cold front will lag behind the initial mid and upper level dynamics. The front will approach the region on Tuesday with band of precip moving through from west to east through the afternoon. Did opt to go a bit lower QPF wise for the far SE, given the better dynamics are early in the day mainly north of the Hal Rogers Parkway. Either way did keep CAT POPs given the chances of seeing measurable precip are reasonably high. Also keep the slight thunder along the highest areas of POPs through the day and again this seems to follow best areas of MUCAPE. .LONG TERM...(Tuesday night through Sunday) Issued at 348 AM EST MON JAN 16 2017 The GFS and ECMWF have come into better agreement since yesterday. There are some differences in the details at long range, but they show good agreement on the overall pattern. It`s still an expectation of overall mild temperatures and periodic showers. For specifics, a cold front will be exiting southeast out of the area on Tuesday evening. Showers may linger, especially in our southeast counties. They will be due not only to exiting deep moisture along the front, but also residual shallow moisture in the post cold frontal regime, with an upper trough axis not passing until Wednesday morning. Will look for the last of the showers to be gone by Wednesday afternoon. Ridging at the surface and aloft then builds in by Wednesday evening, with decreasing clouds. The respite from inclement weather will be short-lived. The ridging will be moving to our east by Thursday morning, and an upper level low coming out of the southwest CONUS will begin its influence. The Gulf of Mexico will open up for overrunning moisture. Clouds should already start to thicken from southwest to northeast by Thursday. In fact, the NAM and ECMWF even have light precip arriving in our southwest counties by Thursday morning. Initially, the better moisture transport and highest POP will remain to our southwest. Eventually, the entire system moves northeast, and an area of showers is expected to move northeast over the JKL forecast area late Thursday night into Friday. This is largely an upper level system, and we will still be left in a mild air mass after it passes. Weak upper level ridging moves in again Friday night, with fair weather that lasts through Saturday. Yet another upper level system should emerge from the southwest CONUS during the weekend. This one is forecast to grow into a much larger trough over the Mississippi Valley before the weekend is finished. Gulf moisture flowing northward around the storm system will lead to another round of showers moving in from the southwest before the weekend is finished. && .AVIATION...
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(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 140 PM EST MON JAN 16 2017 As a warm front continues to advance north and east, vis and or cig has improved to VFR in the warm sector. VFR should continue until a shortwave trough and cold front begin to approach the area tonight and into Tuesday. As the lower levels begin to saturate again tonight as showers return, MVFR should return from northwest to southeast between 2Z and 9Z. South to southeast winds should remain on the light side through 6Z to 9Z, and then begin to increase and veer to the southwest as the front approaches. Thunderstorms will also be possible beginning around 9Z and then lingering as late as 22Z in the far southeast as the front moves in. Low level wind shear will be possible as winds aloft increase ahead of the front and a LLJ increases after 6Z. However, this threat will go away as the thunderstorm threat arrives.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...DJ LONG TERM...HAL AVIATION...JP

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