Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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891 FXUS62 KGSP 300727 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 327 AM EDT Mon Sep 30 2024 .SYNOPSIS... A large area of low pressure will slowly drift east out of the Ohio Valley today leading to another round of scattered light showers, mainly across the mountains. The upper low will finally lift north and east of the area on Tuesday before a weak, moisture starved cold front tracks across the area on Wednesday. Dry high pressure will build in behind the departing cold front Thursday into Friday before another cold front tracks across the area early Saturday, bringing cooler temperatures behind it on Sunday. && .NEAR TERM /THROUGH TONIGHT/... Key Messages: 1) Scattered Showers Expected Again this Afternoon and Evening, Mainly in Western North Carolina 2) Rainfall Amounts will Remain Light (Generally Half an Inch or Less) 3) Patchy Fog and Low Stratus Possible this Morning and Again Tonight As of 300 AM EDT Monday: Seeing thick cloud cover across portions of western North Carolina this morning, with thick cloud cover lifting north across the South Carolina Upstate and northeast Georgia. This will act to limit radiational cooling through daybreak, keeping lows this morning around 10-13 degrees above climo. Patchy fog and low stratus should develop across western North Carolina later this morning, with low stratus developing mainly south of I-85 in the South Carolina Upstate. Pockets of patchy fog should develop across portions of the SC Upstate as well. Already seeing fog at the Pickens County Airport as well as the Jackson County Airport this morning. Light showers have been lifting northeast across the Upper Savannah River Valley the last few hours and are currently grazing Elbert, Abbeville, and Greenwood Counties. The HRRR has this activity continuing to lift across the eastern fringe of the forecast area through the morning hours, reaching Charlotte around daybreak. An upper low tracking will track east out of the Ohio Valley towards the Mid-Atlantic through the near term. This will allow for another round of scattered showers to develop this afternoon and evening, mainly across western North Carolina. Have the highest PoPs (likely, 55%-65%) mainly north of I-40, with lower PoPs (chance, 15%-40%) elsewhere. Rainfall amounts will remain light, generally half an inch or less. Highs will be similar to yesterday and a few degrees above climo. Dewpoints will be a bit higher compared to yesterday so it should be a little more humid today. Cloud cover looks to thin out gradually by this evening, mainly east of the mountains, before gradually filling back in overnight into daybreak Tuesday. This will act to keep lows tonight ~10-12 degrees above climo. Low stratus and patchy fog may develop again overnight into daybreak Tuesday. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 230 AM EDT Monday: Isolated to scattered showers are expected Tuesday, mainly across the mountains and I-40 corridor as moisture rotates around the departing upper low and across the area. With little in the way of instability, thunderstorms aren`t expected and QPF should be light. A weak short wave pushes a weak, dry cold front across the area Wednesday. Highs will be near to a few degrees above normal. Lows will be around 5 degrees above normal. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 245 AM EDT Monday: A weak upper ridge builds over the area Thursday then moves east as a series of weak short waves cross the area Friday and Saturday with a weak cold front crossing the area Saturday. Weak moisture return and forcing could lead to spotty showers, especially on Friday. A dry forecast is currently expected on Sunday with the front to our south. Guidance is in better agreement regarding the potential tropical cyclone developing in the Gulf of Mexico. The short waves moving across the eastern CONUS keep any developing system to our south, moving east across central Florida. Of course, everyone in the Western Carolinas and Northeast Georgia should keep up with the latest forecasts. Highs remain near to slightly above normal through Saturday then drop a little below normal for Sunday. Lows remain nearly steady 5 to 10 degrees above normal. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: Dry and VFR across the terminals as of 06Z. KAND should see some patchy, MVFR fog develop and linger through daybreak. KAVL and KHKY are most likely to see both cigs and vsbys lower to MVFR to IFR levels around daybreak so have TEMPOs to account for this at both terminals. KCLT may see MVFR cigs develop around daybreak and the last few runs of the HRRR continue to show -SHRA tracking over KCLT later this morning so have a TEMPO to account for this from 11Z-15Z. Fog should lift out between 13Z-15Z across the NC terminals, with MVFR cigs lingering through the morning hours before lifting to VFR levels this afternoon. The SC Upstate sites should see cigs remain VFR through the 06Z TAF period. Scattered -SHRA is mostly expected to develop across mainly the mountains this afternoon/evening so have a PROB30 at KAVL from 18Z- 20Z. Maintained a PROB30 from 20-24Z at KHKY but confidence on this is lower as activity may not reach the terminal. Winds will be calm to light and VRB through the early morning hours before picking up out of the S/SW by mid-morning. KAVL will see winds turn NW late this afternoon into tonight. Winds across the SC Upstate terminals will turn W/WSW this evening into tonight, becoming light. Winds at KAVL and KCLT should turn calm to light and VRB this evening into tonight. Outlook: An upper low will slowly push north and east of the Appalachians on Tuesday, keeping scattered -SHRA around. Drier conditions return mid to late week as high pressure builds into the region. Fog/low stratus will be possible overnight into daybreak each day, mainly in the mountain valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...RWH LONG TERM...RWH AVIATION...AR