####018006461#### FXUS61 KILN 031320 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 920 AM EDT Fri May 3 2024 .SYNOPSIS... A weak cold front will move east across the area later today and into tonight. This will bring showers and a chance for thunderstorms today into Saturday, along with some cooler temperatures. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... The forecast remains on track: Embedded mid level energy in southwest flow aloft will lift northeast across the Ohio Valley region through this afternoon. This will be accompanied by a weak cold front that will push into our area from the west later today. Moist southwest flow ahead of this will allow for showers to overspread mainly our western areas through mid morning and then the remainder of our area heading into this afternoon. Instability will remain fairly marginal so will just allow for a chance of some embedded thunderstorms today. With some cooler air moving in from the west, highs today will range from the mid 70s west to the lower 80s east. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/... The mid level energy will push off to the east through tonight as the weak cold front gradually weakens as it moves across our eastern areas. As a result, expect an overall decreasing trend in pcpn from the west tonight with overnight lows in the upper 50s to lower 60s. Southwest flow will persist aloft through the day on Saturday with some weak mid level energy again lifting northeast across the region. Afternoon highs will be in the mid to upper 70s with sbcapes climbing up to around 1000 J/KG or so through the afternoon. With forcing aloft fairly weak, will limit pops to mainly chance category across much of the area for Saturday. The exception may be across our east, closer to the washing out front, where will include some likely pops across at least our far east during the afternoon. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... While the forecast may seem a bit muddied with a potential of showers and thunderstorms through the period, there is good reasoning to have them there. First, overnight lows are only 5-10 degrees below normal. Normal high temperatures. A clear signal where temperatures across the region drop below 60 overnight doesn't seem to come about until Friday night (beyond this forecast). Thursday night looks to be within a few degrees of 60 across the CWA, but until then, 60-65 is expected. The warmest nights will be Tuesday and Wednesday where some locations to the southeast might only drop into the upper 60s. This prolonged period of overnight warmth leads to/stems from an abundance of moisture in the area. Couple this moisture with high temperatures generally running from the mid 70s to around 80 and forcing mechanisms at the surface or aloft at one time or another, and you just can't rule out shower and thunderstorm activity. More like summer, only without the blisteringly higher temperatures one might expect. During the period, Tuesday will see everyone within a few degrees of 80 but Wednesday will be the warmest with lower 80s expected, and some mid 80s possible in the southern CWA. Both high and low temperatures from the Euro ensembles show a fairly tight standard deviation of 2-3 through the entire forecast, meaning a higher confidence in narrowing the expected range in both high and low temps. Second, lifting mechanisms of one sort or another remain a larger than average threat to be over the Ohio Valley and CWA for this period. Saturday night will start with lingering storms that should be decaying after initiation from daytime heating. A cold front is pushing in overnight and while weakening, is still moving into a relatively moist environment and could propagate any lingering storms through the night. This front stretches and weakens on Sunday, but maintains a moisture boundary due to a strong high pressure center to the north. This could lead to showers over the southern CWA during the day and more overnight as the remnant boundary becomes more pronounced from w-e. Monday/Monday night keeps the boundary stretched through the CWA. It exits north-northeast on Tuesday and NBM pops given are much too high with likely in the west. A simple chance of showers/storms would be the better middle ground forecast. Now on Wednesday, warm sector showers/storms on southwest flow are more likely and could continue overnight. A surface low/front is progged on Thursday with the mean sw flow aloft not showing much change. Friday's potential of storms is focused on the potential of a surface low developing near/west of the CWA ahead of a l/w H5 trough, with the low dropping a front through the region. The cumulative pattern suggests potential rainfall/flooding issues either with individual MCS episodes or from repeated rounds of convection. This is as the upper ridge slowly flattens and low-mid level flow lines up wsw by mid week. Starting Friday, an effective frontal passage should begin to settle south of the area with cooler/drier conditions possible for the weekend. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... An upper level disturbance will lift northeast across the Ohio Valley today into tonight as a weak cold moves into the area from the west. This will lead to occasional showers and a few thunderstorms, primarily through today. Will generally cover this with a prevailing -shra, although there will likely be breaks in the showers at times today. Will keep prevailing conditions VFR, although some occasional MVFR conditions will be possible in some of the more significant showers. Will linger some VCSHs in the TAFs through this evening but we should see an overall decreasing trend in coverage from the west tonight. Some MVFR cigs and vsbys will then develop later tonight into Saturday morning. OUTLOOK...Thunderstorms possible at times through Tuesday. MVFR conditions are possible again Sunday morning. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...JGL NEAR TERM...Campbell/JGL SHORT TERM...JGL LONG TERM...Franks AVIATION...JGL ####018005781#### FXUS62 KCHS 031323 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 923 AM EDT Fri May 3 2024 .SYNOPSIS... Atlantic high pressure will remain across the Southeast through much of next week. && .NEAR TERM /THROUGH TONIGHT/... The remainder of the Dense Fog Advisory has been cancelled. Visibilities will continue to improve as the fog/stratus mix out. Today: It will be another warm one across Southeast South Carolina and Southeast Georgia. Morning GOES-E multi-layer water vapor analysis and RAP initialization progs show subtropical ridging remains in place across the Southeast U.S. this morning with the ridge axis centered just offshore the South Carolina and Georgia coast. This ridge will slowly propagate farther out in the Atlantic today as weak impulses move across the Deep South into the western Southeast States. Conditions will favor the genesis of another progressive pure sea breeze with the boundary propagating steadily inland through the local area through the afternoon and evening. 850 hPa theta-e pooling coupled across the far interior with some mixed-layer instability (MLCAPE ~1200 J/kg) per modified RAP soundings at KSBO and KMHP would suggest some convection that develops over the CSRA and east-central Georgia could meander into roughly the Reidsville-Millen corridor late this afternoon and evening. Slight chance pops were maintained in this area to account for this possibility. The fog/stratus will lift into another healthy cumulus field this afternoon which will scour out with the passage of the sea breeze. Some high clouds will pass through aloft as well. The net result will be mostly sunny to partly cloudy skies for most areas. Highs from the upper 80s/near 90 inland to the mid-upper 70s at the beaches look on track. Tonight: A better looking short wave trough moves through the Tennessee Valley and northern Gulf coast. This along with any outflow boundaries from prior convection in and near the area, will allow for isolated or scattered showers and a few t-storms to occur. This is mainly far inland sections. There will be at least some form of fog again after midnight given the southeast and south flow in the boundary layer. However, there is likely too much mid and high level clouds from the nearby convection for dense fog to occur. We currently have mention of the "patchy" fog qualifier, and we will monitor for any dense fog potential. Low temperatures will be several degrees above climo. && .SHORT TERM /SATURDAY THROUGH MONDAY/... A mid-level ridge axis will push off the Southeast coast Saturday with passing waves of shortwave energy across the region through the short term forecast period. High pressure will remain the primary feature at the surface. Convection should be a bit more active over the weekend and into Monday with the presence of deeper moisture as PWATs increase to 1.5+ inches. Coverage of showers/thunderstorms will be highest in the daytime when instability is maximized, but with some upper forcing in play activity could linger into the overnight period. The greatest chances are focused away from the immediate coast owing to a progressive sea breeze. High temperatures will generally peak in the low to mid 80s over the weekend, warming into the mid to upper 80s Monday. Overnight lows are only expected to drop to the mid to upper 60s, with locations right along the beaches and Downtown Charleston near 70 degrees. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... Atlantic high pressure will persist through the middle of next week. Chances for showers/thunderstorms are limited Tuesday as weak forcing/remnant shortwave energy passes offshore the Mid Atlantic coast. Beyond Tuesday, rainfall chances are little to none as a ridge rebuilds overhead. This will allow max temperatures to rise into the low/mid 90s by mid next week, possibly approaching record levels by Wednesday/Thursday. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... KCHS/KJZI/KSAV: Other than a little light fog at KSAV through 13, VFR will prevail at all terminals. The potential for fog tonight t is less than recent nights, and would likely occur inland from the terminals anyway. There are no concerns for SHRA or TSRA at any the terminals with the 12Z TAFs. Extended Aviation Outlook: Scattered showers and thunderstorms are possible through Monday. && .MARINE... Today: High pressure from the Atlantic will be the main feature, and even with sea breeze influences this afternoon, SE winds will be no more than about 10 kt. Seas will be only around 2 feet. Even though it is light, the onshore flow will keep any land based fog off the Atlantic. The exceptions will be Charleston Harbor (especially the northern part of the harbor near the North Charleston Port) and the Port of Savannah, where some of the nearby fog from over the land could drift into those areas early this morning. At this time no Dense Fog Advisory is planned. Tonight: Weak high pressure continues across the maritime community. Once again the SE winds are no more than about 10 kt, with seas just 2 feet. Saturday through Wednesday: Atlantic high pressure will maintain benign conditions over the local waters. Southerly winds in the morning will back out of the southeast during the afternoon and evening hours nearly each day as the sea breeze develops. Winds will average 10-15 kt with seas 2-3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$