Marine Weather and Tide Forecast for Franklin, NC
May 17, 2024 4:26 AM EDT (08:26 UTC) Change Location
 | Sunrise 6:23 AM Sunset 8:29 PM Moonrise 2:12 PM Moonset 2:27 AM |
Area Discussion for - Greenville-Spartanburg, SC
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FXUS62 KGSP 170738 AFDGSP
Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 338 AM EDT Fri May 17 2024
SYNOPSIS
A warm front and weak low pressure system will bring frequent chances for showers and thunderstorms today through the weekend. Somewhat drier conditions return early next week resulting in only isolated afternoon and evening showers and storms Monday and Tuesday.
NEAR TERM /THROUGH TONIGHT/
As of 300 AM Fri: Broad area of upper divergence will shift east out of the lower Mississippi Valley this morning, associated with jet streak and shortwave south of the Great Lakes. Meanwhile, weakening MCS will move along the Gulf Coast. Abundant cirrus are creeping in our direction and should follow the upper ridge axis. Think these cirrus are filling in too slowly over our area to have a big impact on morning mins; at least patchy fog may develop near the major rivers by daybreak.
Vort maxes from the Gulf Coast convection look to advect northeast to our vicinity later this morning, along with cooler air at 700 mb. Prog soundings show MUCAPE ticking upward to match within a relatively shallow layer, and CAMs variously develop a wave of showers from around midday and early afternoon, although they are not in particularly good agreement as to where this occurs. Thunder appears isolated at best with this activity owing CAPE being relatively shallow and at warm temps. Light and increasingly moist low level southerly flow will develop and could produce some light precip near the SW NC mountains or Escarpment as well. Thus PoPs increase a bit faster than we had previously advertised, still mainly focused over the mountains at onset. Meanwhile, warm front will shift northward thru the Deep South, associated with developing sfc low in MS/AL. The approach of this front warrants further increases in PoP and expansion across the rest of the CWA in the afternoon, with likely to categorical chances for the whole area by late evening. This second round of precip is more likely to induce thunder, particularly in our southern half, with deep convection possible albeit most likely elevated from the warm frontal inversion. This MUCAPE appears meager enough that severe wx looks unlikely. Peak PoPs will follow the warm front, behind which moist layer becomes more shallow albeit with weak upglide continuing. Low stratus are likely to develop in the evening and persist into Saturday; unclear at this time whether the end of precip will be associated with fog formation but a mild, muggy night appears a good bet. WPC Marginal Risk seems to adequately cover the area most likely to see convective rainfall rates thru tonight.
The clouds and showers will keep temps a few degrees below normal in the west, but still may rise a degree or two above normal in the east where these are less of a factor.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
As of 245 AM EDT Friday: A positively tilted southern stream upper trough will cross the TN valley on Saturday providing some QG forcing atop the FA during peak heating. Precip from Friday night may cause a frontal boundary to set up roughly along or just north of the I-20 corridor early Saturday. The air mass south of the boundary will be fairly unstable along with good bulk shear of 40-50 kt. For our forecast area, CAPE looks to be 1500 J/kg or less, with the various deterministic models showing the maximum sbCAPE in differing parts of the area. Shear will also not be quite as high as to our south. So this muddies the severe threat quite a bit. The latest CAMs show a rather disorganized convective mode across the CWFA Saturday, and a marginal risk in the SPC Day 2 Outlook seems reasonable. With more convection expected to our south, and veering deep-layer flow to nearly due westerly, will also limit excessive rain potential, as PWATs trend down. Despite plenty of cloud cover, highs will be near normal with humid low-mid 60 dewpts.
The low pressure system slows down once it reaches the NC Coast Sunday morning, with the CWFA in the NELY-flow side of the system. Wrap-around moisture should keep skies cloudy to mostly cloudy with showers and mainly general thunderstorms possible. The air wrapping around the system should be less unstable and bulk shear will generally 20 kt or less, so severe thunderstorm chances will be low. Heavy rain may localize along the escarpment with nearly parallel deep-layer flow and some ELY upslope, but overall, no strong signals for excessive rainfall/flooding. Highs will be kept below normal, especially across the NC foothills and Piedmont.
LONG TERM /MONDAY THROUGH THURSDAY/
As of 315 AM EDT Friday: The low pressure system along the NC coast should drift far enough east to allow more dry air to work into the forecast area from the N/NE on Monday. This should allow for more breaks in the clouds and lower precip chances. With more insolation, could see diurnal convection across the mountains, with isolated showers possible across the Piedmont, but severe storm threat should remain low. Temps will be slightly below normal thanks to continued cool NELY flow. High pressure builds in Tuesday, making for largely dry wx across the area and temps returning to normal.
The 00z medium range guidance has come into better agreement on the next cold front to affect the forecast area. Earlier guidance had moisture and PoPs returning Wednesday, but now have backed off. So Wednesday may end up being dry with temps warming to slightly above normal. With an upper ridge building over the Southeast, the front will weaken as it tries to push into the area Thursday. The 00z guidance shows meager QPF response with the front, and isolated to scattered convection is expected. The NBM PoPs may be a little overdone, if this trend holds, but for now will keep the solid chc PoPs in there. Slightly above-normal temps will continue thru the end of the week.
AVIATION /08Z FRIDAY THROUGH TUESDAY/
At KCLT and elsewhere: Relatively low confidence TAFs with multiple sources of weak forcing and differing signals among guidance members. Cirrus will increase early this morning but deck does not look likely to fill in quickly enough to keep radiation fog at bay in the river valleys. TEMPO MVFR vsby and SCT002 for KAVL, but the other sites chance of fog small enough to omit. Lapse rates will improve after daybreak with arrival of weak shortwave preceding sfc/upper low in the southern Plains. This is expected to spawn scattered SHRA/TSRA in the late morning to early afternoon which has prompted TEMPO impacts earlier in the day than usual. Such convective development is likely to result in spotty low VFR cigs, aside from the higher cloud decks thickening. This activity may weaken or become more isolated before more widespread precip and perhaps embedded TSRA arrive with warm front tonight. Warm front appears likely to produce MVFR and then IFR cigs tonight, with areas of fog developing after precip. Generally southerly winds this period.
Outlook: Periods of convection, which could be widespread at times, are expected through the weekend. Late night/early morning restrictions in low stratus and/or fog will also be possible. Drier weather is expected to return early in the next work week.
GSP WATCHES/WARNINGS/ADVISORIES
GA...None.
NC...None.
SC...None.
Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 338 AM EDT Fri May 17 2024
SYNOPSIS
A warm front and weak low pressure system will bring frequent chances for showers and thunderstorms today through the weekend. Somewhat drier conditions return early next week resulting in only isolated afternoon and evening showers and storms Monday and Tuesday.
NEAR TERM /THROUGH TONIGHT/
As of 300 AM Fri: Broad area of upper divergence will shift east out of the lower Mississippi Valley this morning, associated with jet streak and shortwave south of the Great Lakes. Meanwhile, weakening MCS will move along the Gulf Coast. Abundant cirrus are creeping in our direction and should follow the upper ridge axis. Think these cirrus are filling in too slowly over our area to have a big impact on morning mins; at least patchy fog may develop near the major rivers by daybreak.
Vort maxes from the Gulf Coast convection look to advect northeast to our vicinity later this morning, along with cooler air at 700 mb. Prog soundings show MUCAPE ticking upward to match within a relatively shallow layer, and CAMs variously develop a wave of showers from around midday and early afternoon, although they are not in particularly good agreement as to where this occurs. Thunder appears isolated at best with this activity owing CAPE being relatively shallow and at warm temps. Light and increasingly moist low level southerly flow will develop and could produce some light precip near the SW NC mountains or Escarpment as well. Thus PoPs increase a bit faster than we had previously advertised, still mainly focused over the mountains at onset. Meanwhile, warm front will shift northward thru the Deep South, associated with developing sfc low in MS/AL. The approach of this front warrants further increases in PoP and expansion across the rest of the CWA in the afternoon, with likely to categorical chances for the whole area by late evening. This second round of precip is more likely to induce thunder, particularly in our southern half, with deep convection possible albeit most likely elevated from the warm frontal inversion. This MUCAPE appears meager enough that severe wx looks unlikely. Peak PoPs will follow the warm front, behind which moist layer becomes more shallow albeit with weak upglide continuing. Low stratus are likely to develop in the evening and persist into Saturday; unclear at this time whether the end of precip will be associated with fog formation but a mild, muggy night appears a good bet. WPC Marginal Risk seems to adequately cover the area most likely to see convective rainfall rates thru tonight.
The clouds and showers will keep temps a few degrees below normal in the west, but still may rise a degree or two above normal in the east where these are less of a factor.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
As of 245 AM EDT Friday: A positively tilted southern stream upper trough will cross the TN valley on Saturday providing some QG forcing atop the FA during peak heating. Precip from Friday night may cause a frontal boundary to set up roughly along or just north of the I-20 corridor early Saturday. The air mass south of the boundary will be fairly unstable along with good bulk shear of 40-50 kt. For our forecast area, CAPE looks to be 1500 J/kg or less, with the various deterministic models showing the maximum sbCAPE in differing parts of the area. Shear will also not be quite as high as to our south. So this muddies the severe threat quite a bit. The latest CAMs show a rather disorganized convective mode across the CWFA Saturday, and a marginal risk in the SPC Day 2 Outlook seems reasonable. With more convection expected to our south, and veering deep-layer flow to nearly due westerly, will also limit excessive rain potential, as PWATs trend down. Despite plenty of cloud cover, highs will be near normal with humid low-mid 60 dewpts.
The low pressure system slows down once it reaches the NC Coast Sunday morning, with the CWFA in the NELY-flow side of the system. Wrap-around moisture should keep skies cloudy to mostly cloudy with showers and mainly general thunderstorms possible. The air wrapping around the system should be less unstable and bulk shear will generally 20 kt or less, so severe thunderstorm chances will be low. Heavy rain may localize along the escarpment with nearly parallel deep-layer flow and some ELY upslope, but overall, no strong signals for excessive rainfall/flooding. Highs will be kept below normal, especially across the NC foothills and Piedmont.
LONG TERM /MONDAY THROUGH THURSDAY/
As of 315 AM EDT Friday: The low pressure system along the NC coast should drift far enough east to allow more dry air to work into the forecast area from the N/NE on Monday. This should allow for more breaks in the clouds and lower precip chances. With more insolation, could see diurnal convection across the mountains, with isolated showers possible across the Piedmont, but severe storm threat should remain low. Temps will be slightly below normal thanks to continued cool NELY flow. High pressure builds in Tuesday, making for largely dry wx across the area and temps returning to normal.
The 00z medium range guidance has come into better agreement on the next cold front to affect the forecast area. Earlier guidance had moisture and PoPs returning Wednesday, but now have backed off. So Wednesday may end up being dry with temps warming to slightly above normal. With an upper ridge building over the Southeast, the front will weaken as it tries to push into the area Thursday. The 00z guidance shows meager QPF response with the front, and isolated to scattered convection is expected. The NBM PoPs may be a little overdone, if this trend holds, but for now will keep the solid chc PoPs in there. Slightly above-normal temps will continue thru the end of the week.
AVIATION /08Z FRIDAY THROUGH TUESDAY/
At KCLT and elsewhere: Relatively low confidence TAFs with multiple sources of weak forcing and differing signals among guidance members. Cirrus will increase early this morning but deck does not look likely to fill in quickly enough to keep radiation fog at bay in the river valleys. TEMPO MVFR vsby and SCT002 for KAVL, but the other sites chance of fog small enough to omit. Lapse rates will improve after daybreak with arrival of weak shortwave preceding sfc/upper low in the southern Plains. This is expected to spawn scattered SHRA/TSRA in the late morning to early afternoon which has prompted TEMPO impacts earlier in the day than usual. Such convective development is likely to result in spotty low VFR cigs, aside from the higher cloud decks thickening. This activity may weaken or become more isolated before more widespread precip and perhaps embedded TSRA arrive with warm front tonight. Warm front appears likely to produce MVFR and then IFR cigs tonight, with areas of fog developing after precip. Generally southerly winds this period.
Outlook: Periods of convection, which could be widespread at times, are expected through the weekend. Late night/early morning restrictions in low stratus and/or fog will also be possible. Drier weather is expected to return early in the next work week.
GSP WATCHES/WARNINGS/ADVISORIES
GA...None.
NC...None.
SC...None.
Greer, SC,
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