Area Forecast Discussion
Issued by NWS Jackson, KY

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277 FXUS63 KJKL 230146 AFDJKL Area Forecast Discussion National Weather Service Jackson KY 946 PM EDT FRI JUL 22 2016 .UPDATE... Issued at 946 PM EDT FRI JUL 22 2016 WSR-88D radar indicated much of the storm activity has progressed generally along and south of the Hal Rogers Parkway this late evening hour. Much of this likely still going because of the higher PWAT values and SW propagating outflow boundary. Overall this activity will continue to trend down and we should see improving conditions. Even so those under one of the stronger storms you will still see locally heavy rainfall and frequent lightning. Given a good portion of the CWA has seen rain did opt to add patchy fog in valleys starting now. Model wise the CAMS still struggling, with HRRR only model remotely handling current trends. This is likely due to the hourly initialization and it really didn`t have the idea till 22Z run. Overall biggest change was updating pops to reflect current trends. UPDATE Issued at 615 PM EDT FRI JUL 22 2016 WSR-88D radar indicating isolated to scattered showers and storms are tracking slowly south and east across eastern KY. The best coverage has resided across the north and east portions of the CWA. The CAMS have struggled given the more mesoscale driven nature of the storms. Also not handling the outflow boundary which is emanating southwest from the storms. While this outflow may kick off a few more storms as it moves SW, the loss of daytime heating will lead to a down tick overall in any storms ongoing or that develop. Those that do see storms will see heavy rain, gusty winds, and frequent lightning. More minor updates to mainly pop to better handle ongoing convection. && .SHORT TERM...(This evening through Saturday night) Issued at 314 PM EDT FRI JUL 22 2016 Two issues to address in the short term part of the forecast. First is the chance for thunderstorms for the remainder of today and then on Saturday. A weak mid level short wave is passing across the area this afternoon. Convection that has been developing in the northern part of our area has been short lived with an apparent mid level cap in place which is hinted at by some of the model data. As this cap continues to weaken should see isolated to scattered storms mainly in the north and west for the latter part of the afternoon. With outflow from any convection late today possibly triggering additional convection, the threat for a few showers and thunderstorms will linger into the overnight. With the passage of the short wave tonight it appears that the better chance for thunderstorms on Saturday will be over the southern part of the area. However chance will remain low, about 30 percent chance in the south and 20 percent chance in the north on Saturday. The second issue to address is the heat for Saturday. Current temperature forecast for Saturday is for maximums in the lower 90s, and this will combine with humidity to once again push heat indices to around 100. With heat advisory criteria of 105 degrees will still not need to issue a heat advisory for our area. .LONG TERM...(Sunday through Friday) Issued at 314 PM EDT FRI JUL 22 2016 Models continue to show good agreement and continuity with mid and upper level features through the period. Broad, flattened mid and upper level ridge across the southern CONUS buckles in response to multiple short wave troughs tracking across the northern tier. The main center of the high retrogrades to the west coast just as the all too familiar Bermuda High reforms off the southeastern United States. In between a mean trough develops over the Upper Mid-West and Great Lake Region by the end of the forecast window. With our area lying on the southern periphery of an active northern stream, sensible weather will manage some isolated to at times scattered convection at just about any time through the period. There will be a greater chance of rainfall early next week as a cold frontal boundary drops southward to the Ohio River by late Monday, or possibly Tuesday. This boundary stalls out and will tend to keep any convection focused across the region through mid week. What`s left of the boundary lifts northward Thursday, just as another trough begins to drop into the region from the northwest by late Thursday or Friday. The loss of mid and upper level ridging combined with daily convection will help keep our high temperatures close to normal for this time of the year, or possibly slightly cooler. But overall our weather will remain quite muggy. Overnight lows will be warm, running a little above normals. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 723 PM EDT FRI JUL 22 2016 Most sites are beginning the TAF period VFR with exception of some sites seeing vis restrictions. This mainly due to rain and storms moving across those sites. That said the WSR-88D radar continues to show rain and storms across portion of eastern KY this hour. Many of these storms have been sparked by a outflow boundary that continues to progress southwest. This activity will die off as sunsets and we loose daytime heating. Then the question is fog overnight, right now the guidance wants to hit this hard. Leaned toward southern sites of LOZ/SME and also SYM given more rain. All and all think most of this will be confined to the typical river valley locales. Winds will remain light, but sites that see a stronger storm could see 15 to 20 knot gust. Did go VCTS for the southern sites given overall higher pop, but will likely have to look at this closer in next TAF issuance area wide. && .JKL Watches/Warnings/Advisories... None. && $$ UPDATE...DJ SHORT TERM...SBH LONG TERM...RAY AVIATION...DJ

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