Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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195 FXUS62 KGSP 090019 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 819 PM EDT Sat Jun 8 2024 .SYNOPSIS... A cold front moves in on Sunday with returning shower and thunderstorm chances. The front moves south of the area Monday and Tuesday. Forecast confidence lowers through the rest of the week as overall pattern is uncertain. For now, a chance of afternoon and evening showers and thunderstorms is expected with above normal temperatures. && .NEAR TERM /THROUGH SUNDAY/... Key Messages: 1) Dry Conditions Linger into Tonight 2) Isolated Strong to Severe Storms are Possible on Sunday As of 5:45 PM EDT Saturday: Cirrus with some patches of altocu continue to make their way eastward across our fcst area early this evening. CAMs appear to have backed off on producing any showers over our area thru the evening except along the NC/TN Border and over the northern NC mtns. Nonetheless, most of the rain that does fall likely won`t reach the ground due to the dry air currently in place. Lows tonight will end up about 3 to 5 degrees above climo thanks to lingering cirrus and SWLY flow. Otherwise, cirrus will gradually increase in coverage Sunday morning as a cold front approaches out of the west. The front will track over the forecast area Sunday afternoon and evening, bringing shower and thunderstorm chances back into the forecast. Have the highest PoPs (high-end chance to low-end likely, 40%-60%) confined to the mountains with lower PoPs (chance, 15%-35%) elsewhere. Mainly rain showers are expected ahead of the front Sun morning, with thunderstorms expected to develop during the afternoon and early evening hours. The SPC Day 2 Severe Wx Outlook has introduced a Marginal Risk for isolated severe storms on Sun. This looks reasonable as 35-45 kts of deep shear will be in place during peak heating along with SBCAPE up to 1200 J/kg across portions of the fcst area. The main hazards with any severe storm that develops will be large hail and damaging wind gusts. Temperatures Sun afternoon will be much warmer (~5 degrees above climo) due to increasing westerly flow ahead of the cold front. Highs will climb into the upper 80s and lower 90s east of the mtns. Some low-end wind gusts will be possible, mainly across the mtns, Sun afternoon and early evening in association with the front. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 145 PM EDT Saturday: Short waves carve a trough over the East Coast Monday with the trough axis moving off shore Tuesday. At the surface, a cold front crosses the area Sunday night, stalls near the area Monday before pushing south on Tuesday. Expect ongoing convection Sunday evening will taper off through the night, but isolated showers may linger into Monday with lingering low level moisture and weak forcing. Dry conditions expected on Tuesday as a drier air mass moves in from the north. Breezy conditions Sunday night and Monday will taper off Monday evening as the pressure gradient relaxes. Lows near to slightly above normal Sunday night drop around 5 degrees Monday night. Highs Sunday and Monday remain nearly steady around normal. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 210 PM EDT Saturday: Guidance continues to show little run to run consistency as they waffle back and front from a wetter to drier pattern through the period. Have gone close to the model blend given the low confidence in the forecast which results in isolated to scattered mainly diurnal convection each day. The overall pattern begins with a short wave ridge on Wednesday then a weak zonal flow which weakens or becomes a ridge for Saturday. Weak high pressure over the area Wednesday moves east as cyclogenesis takes place along the Gulf Coast. The resulting low pressure center may remain nearly stationary with a decent southerly fetch into the area. The low may cross FL and move up the Atlantic Coast, which would also keep moisture over the area. Or the low could remain suppressed as it crosses FL and moves into the Atlantic, which would be a relatively dry pattern. This is why confidence is low and forecast relies on the model blend. This also results in temps bouncing around but remaining above normal through the period. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Key Messages: 1) Dry Conditions Linger thru Tonight 2) Shower and Thunderstorm Chances Return Sunday At KCLT and elsewhere: expect VFR conditions to continue thru the 00z taf period. Mid and upper level clouds will remain sct over the area thru tonight and into the overnight. A cold front approaching from the NW will move thru our area on Sunday and bring sct showers in the afternoon with a round of thunderstorms likely that evening. Coverage and timing of both the showers and thunderstorms is still fairly uncertain at this time, so I kept a PROB30 for shra with a PROB30 for tsra later in the day at each terminal. Winds outside of the mtns will weaken tonight and continue to favor a SW to WSW direc- tion thru tomorrow morning. They will become more WLY tomorrow aftn and pick up in speed with some low-end gusts possible, especially at the Upstate terminals, as the cold front moves thru the area. At KAVL, winds will go light and vrb later tonight and eventually pick up from the NW on Sunday with low-end gusts likely. Outlook: drying sfc high pressure is expected to gradually spread over the area on Monday and linger thru the first part of the week. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...RWH NEAR TERM...AR/JPT SHORT TERM...RWH LONG TERM...RWH AVIATION...JPT