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Show Area Forecast Discussion - Charleston, SC (Charleston, SC Area) Selection: |
| #1209043 (Received by flhurricane at: 4:24 AM 21.Nov.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 416 AM EST Thu Nov 21 2024 .SYNOPSIS... Canadian high pressure will build across the area today and will remain the primary feature through early next week. A cold front could approach the area towards the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... Until sunrise: Strong CAA persists across the region, with temperatures continuing to drop over the next couple of hours. Skies remain clear, and dry conditions are expected through the night. Winds should diminish a little over the next 1-2 hours inland and then pick up after sunrise. Gusty northwest winds will make it feel even cooler by daybreak Thursday with wind chills dropping into the upper 30s/lower 40s. Today: With a strong closed upper low moving across the Great Lakes and a high pressure building off to the east, dry weather and cooler temperatures are expected. Breezy conditions are also expected again today, with winds W at 10 to 15 kt with gusts up to 20 kt over land. Highs will reach into the upper 50s to lower 60s. Tonight: W winds will diminish to 5 to 10 kt. Lows will dip into the mid to upper 30s inland and lot to mid 40s along the coast. We expect enough overnight wind to prevent frost development. Lake Winds: Expect winds at 15 to 20 kt with gusts up to 30 over Lake Moultrie throughout the day into tonight. Also, waves of 2-3 ft are expected. This combination creates dangerous wave action on the lake tonight with the worst conditions occurring over the central and eastern portions of the lake. Boaters are encouraged to remain off the lake. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... Deep mid level low will meander over the Northeast on Friday, before exiting on Saturday. The pattern will then flatten and be replaced by weak ridging by the end of the weekend. At the surface, low pressure will finally exit allowing high pressure to continue to build over the local area. Gusty winds are expected on Friday, then the pressure gradient eases through the weekend. Gusts over Lake Moultrie could approach Lake Wind Advisory criteria Friday into Friday night, but at this point remains just shy. Otherwise, expect full sunshine with moderating temperatures. It will be coolest on Friday when highs top out in the mid to upper 50s (~10 degrees below climo). By Sunday, temperatures will recover to the upper 60s. Lows will be chilly, falling solidly into the 30s inland of the coast. Attention then turns to the potential for frost over far interior areas. For Friday night/Saturday morning, while temps are supportive, winds could stay too elevated for widespread frost development. Certainly not out of the question to see patchy frost in more sheltered locations. For Saturday night/Sunday morning, we did go on the cooler side of guidance with ideal radiational cooling conditions in place. As winds are expected to go calm, this could lead to a higher threat for frost. Will continue to monitor trends. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... Surface high pressure will continue to extend into the area early next week, although a cold front could approach during the latter half of the period. Still some uncertainties in the evolution of that feature, whether it actually passes through or stalls, so changes to the forecast are likely. At this point, no rain is in the forecast. Temperatures will be above climo for Monday and Tuesday then possibly cooler for Wednesday if fropa occurs. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... 21/06z TAF Discussion: KCHS/KJZI/KSAV: Now with cold front offshore, gusty northwest winds have developed and will persist into the day Thursday. Clouds have now cleared and will remain clear through the rest of the 06Z TAF period. Thus, VFR will prevail. Extended Aviation Outlook: VFR. Gusty west winds are expected Friday. && .MARINE... Through Thursday: NW winds will become more westerly as we head into the afternoon. Expect winds to range from 10 to 15 kt with gusts up to 30 kt. Seas will range from 2 to 4 ft for the majority of the day, and then increasing 4 to 5 ft tonight. A Gale Warning remains in effect for the Georgia offshore waters beyond 20 NM with high- end Small Craft Advisories for all nearshore legs, including Charleston Harbor. Friday through Tuesday: Gusty west winds will persist over the coastal waters Friday into Friday night, maintaining the ongoing Small Craft Advisories. For the Charleston Harbor, gusts should fall below 25 kt Friday evening so the Advisory is scheduled to come down at 23z/6 PM. Conditions will improve on Saturday, with winds and seas remaining below advisory levels through Tuesday. Winds eventually turn southwest with speeds generally 15 knots or less and seas 1-3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 11 PM EST this evening for SCZ045. MARINE...Small Craft Advisory until 6 PM EST Friday for AMZ330. Small Craft Advisory until 7 AM EST Saturday for AMZ350-352- 354. Gale Warning until 7 AM EST this morning for AMZ374. && $$ |
| #1209029 (Received by flhurricane at: 1:24 AM 21.Nov.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 112 AM EST Thu Nov 21 2024 .SYNOPSIS... A strong cold front will push farther offshore tonight. Canadian high pressure will build across the area Thursday and will remain the primary feature through early next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... No major changes were made for the early morning update. Tonight: Now with the front positioned offshore, strong post- frontal cold air advection will continue to follow for several hours and will usher in a slightly modified cP airmass as the night progresses. Clear skies will also continue for the rest of tonight as clouds have moved offshore with the front. As the winds have now picked up quite a bit, these breezy conditions should pursue overnight. Lows look to bottom out in the lower 40s well inland to the upper 40s/near 50 at the beaches. Gusty northwest winds will make it feel even cooler by daybreak Thursday with wind chills dropping into the upper 30s/lower 40s. Lake Winds: Impressive and deep mixing profiles will develop on Lake Moultrie overnight as strong post-frontal cold air advection ensues with the passage of the cold front. RAP soundings support as much as 35-40 kt of wind at the top of the mixed layer by midnight supporting winds 20-25 kt with gusts at least to 30 kt, if not a tad higher at times. Winds were slightly with waves over the open lake waters building to 2-3 ft. The combination of increasing winds and building waves will make for dangerous wave action on the lake tonight with the worst conditions occurring over the central and eastern portions of the lake. Boaters are encouraged to remain off the lake. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... A powerful closed upper low will swing through the Great Lakes on Thursday then stall near New England Friday into Saturday. Meanwhile, strong high pressure will expand across the Southeast at the surface. Dry weather and below normal temps expected. Highs will top out in the upper 50s to lower 60s on Thursday, then only reach the mid/upper 50s on Friday. Saturday should be a tad warmer with highs in the lower 60s. Lows both nights could dip into the mid to upper 30s inland, though we expect enough overnight wind to prevent widespread frost development. Lake Winds: Gusty west winds are expected to persist over Lake Moultrie Thursday into Thursday evening during which we have a Lake Wind Advisory in effect. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Surface high pressure will maintain influence over the local weather Sunday through Tuesday. Not much going on upstairs with relatively zonal flow. Rain-free forecast in place with warming temperatures through the period. Main forecast concern remains the potential for frost late Saturday night/early Sunday morning as ideal radiational cooling conditions allow temperatures to fall to the mid/upper 30s inland of the coast. Frost is possible, mainly over far interior locations. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... 21/06z TAF Discussion: KCHS/KJZI/KSAV: Now with cold front offshore, gusty northwest winds have developed and will persist into the day Thursday. Clouds have now cleared and will remain clear through the rest of the 06Z TAF period. Thus, VFR will prevail. Extended Aviation Outlook: VFR. Gusty west winds are expected Thursday and Friday. && .MARINE... Tonight: Strong post-frontal cold air advection will overspread the waters overnight with the passage of a cold front. Northwest winds will increase to 25 kt with gusts to 30 kt for the waters within 20 NM and 25-30 kt with gusts 35 kt over Georgia offshore waters out 20-60 NM. A Gale Warning remains in effect for the Georgia offshore waters beyond 20 NM with high- end Small Craft Advisories for all nearshore legs, including Charleston Harbor. Gusts could get close to Gale Warning criteria across the nearshore waters, mainly within 10-20 NM, but these conditions look infrequent enough to not to justify an upgrade to a Gale Warning at this time. This will be closely watched this evening and overnight, however. For Charleston Habor, northwest winds will increase to 20-25 kt with gusts to 30 kt and waves building 2-3 ft. Thursday through Monday: Gusty west winds will persist over the coastal waters Thursday through Friday night, maintaining the ongoing Small Craft Advisories. For the Charleston Harbor, gusts to 25 knots are expected Thursday through Friday. Improvement is expected Saturday with winds and seas remaining below advisory levels through Monday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 11 PM EST this evening for SCZ045. MARINE...Small Craft Advisory until 6 PM EST Friday for AMZ330. Small Craft Advisory until 7 AM EST Saturday for AMZ350-352- 354. Gale Warning until 7 AM EST this morning for AMZ374. && $$ |
