002 FXUS61 KPHI 251948 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 348 PM EDT Fri Jun 25 2021 .SYNOPSIS... High pressure well offshore with remain in place through the weekend and much of next week. A front across the Great Lakes will slowly move east and approach our area towards the middle of next week. && .NEAR TERM /THROUGH SATURDAY/... High pressure remains offshore of the Canadian maritimes tonight through Saturday, which will keep a steady return flow across the Mid Atlantic region. An extended period of warming temperatures and increasing moisture is expected across the area beginning Saturday. Lower cloud cover is expected to increase across the area overnight tonight as the warm and humid air mass begins to affect the area. The low clouds will begin to break up and lift during the morning into the afternoon on Saturday. Patchy fog may also form for some areas due to the increasing low level moisture, especially for areas where winds become light and variable. A couple of weak short wave/vorticity impulses will move across the area, especially on Saturday, so a slight chance of scattered showers, or thunderstorms, will be possible on Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... The fair but increasingly humid pattern continues. After a mild night with increasing humidity Sat night, Sunday looks to be rather hot with highs in the 90s in most areas, except the coastal areas and the higher elevations of the southern Poconos. Dew points will be climbing into the upper 60s and low 70s, so heat index values will climb into the uncomfortable range. The heat index number come up short of an advisory however. Winds will be mostly South to Southwest at 5 to 10 mph. Patchy fog is possible both Sat and Sun nights with some haze possible during the afternoon hours. We have slight chc pops for the NW areas Sunday afternoon, but with the upper ridge across the region, this is probably the highest pops that will be needed attm. && .LONG TERM /MONDAY THROUGH FRIDAY/... A summer pattern will be across the Middle Atlantic region this week with a Bermuda high pressure system offshore. Meanwhile, a front will be across the Great Lakes and into the Ohio Valley which will be inching to the east. The Bermuda high will keep a humid and hot air mass circulating across the region with plenty of daytime sun to make temperatures well above normal for the period. Daytime highs in the low to mid 90s are expected and with the humidity, apparent temps will be close to 100 for many areas during the peak heating hours. It is expected that heat related headlines will be needed this weekend for next week. Precipitation chances are tied to weak disturbances moving across the region and the proximity of the front. Right now, it looks like the chances increase thru the week and will be greatest across the NW areas. Tstms with heavy rains are possible with the humid air mass. We have generally gone along with NBM number for now, but trimmed some in the later periods with not enough confid for categorical or high-likely in the later periods attm. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of Today...VFR conditions continue for all sites. Winds increase to 5-10 knots with occasional gusts around 15 knots, and vary between south-southeast to south-southwest. High confidence. Tonight...VFR conditions expected for the first half of the night. However, ceilings lower to MVFR overnight and eventually IFR overnight and through daybreak Saturday. Winds become southeast 5 knots or less this evening, before becoming light and variable overnight through daybreak Saturday. Moderate confidence. Saturday...IFR or MVFR conditions begin the day, before lifting to VFR by late morning into the afternoon. There is a chance for an isolated shower, which could temporarily lead to lower conditions. Winds increase out of the south to southwest 5-10 knots, with gusts 15-20 knots. Moderate confidence. Outlook... Sat night...VFR. Patchy fog possible. Light winds. Sunday/Sunday night...Mostly VFR. Hazy. Isolated showers/tstms possible KRDG/KABE. Mostly S to SW winds. Mon thru Wed... Mostly VFR with early morning fog and afternoon haze possible. Scattered showers and tstms Tue/Wed with lower VSBYS/CIGS possible. && .MARINE... Through Saturday...Conditions are expected to mostly remain below advisory levels with gusts around 20 knots and seas 3-4 feet. However, winds could approach 25 knots for a couple of hours on Saturday across the northern New Jersey coastal waters. Confidence is low enough to not issue an advisory at this time. Outlook... Typical summer-like conditions with hazy, hot and humid conditions. Mostly South to Southwest winds 10 to 15 knots by day and light at night. Seas mostly around 3 ft on the ocean and 1 to 2 ft across Delaware Bay. Scattered showers and tstms favoring the afternoon and early evening hours. Rip Currents... Given an occasional long period swell remains and the flow is becoming more onshore, we've opted to continue with a MODERATE risk for dangerous rip currents today. Saturday the risk will remain the MODERATE generally only for the afternoon low tide cycle. The risk will likely be low in the morning and late at night however the low tide during the middle of the day is enough to warrant a MODERATE risk. && .TIDES/COASTAL FLOODING... Astronomical tides will be high the next couple of days due to the recent full moon and the continued onshore flow. Some minor tidal flooding is possible with the evening high tide, mainly along the southern New Jersey and Delaware coasts. However, we are not expecting any advisory level flooding to occur. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...O'Hara Near Term...Robertson Short Term...O'Hara Long Term...O'Hara Aviation...O'Hara/Robertson Marine...O'Hara/Robertson Tides/Coastal Flooding...WFO PHI