094 FXUS61 KAKQ 041535 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 1135 AM EDT Mon Sep 4 2023 .SYNOPSIS... High pressure remains centered over the Southeast through the week with dry and hot conditions expected into midweek. An unsettled pattern develops from late week through the weekend with scattered showers and storms possible each day. && .NEAR TERM /THROUGH TONIGHT/... As of 1115 AM EDT Monday... The latest sfc analysis indicates ~1019 mb sfc high pressure centered from southern GA to the TN Valley with a weak sfc trough pushing off the NC coast. Aloft, the flow is NNW as the local area remains located in-between a strong/amplifying ridge centered from the eastern Gulf of Mexico to the Great Lakes and a trough well off the New England coast. High clouds continue to stream SSE through the region, generally thickest across the Delmarva. Temperatures have risen into the mid 80s to near 90F across most of the FA, with locally hotter conditions at RIC ASOS (where it has been as high as 93F and is approaching unrepresentative conditions)/see Climate section for details). Not much change to the forecast for today, as the upper level ridge continues to amplify and build across the local area as the downstream upper low remains nearly stationary well offshore. Models show 850mb temperatures rising to 20-22C this afternoon, with dry and mostly sunny conditions continuing (apart from thin cirrus especially along the coast). Expect high temperatures to be at least a few degrees higher than yesterday, ranging from widespread mid to upper 90s well inland to the low- mid 90s near the coast. Richmond, VA (RIC) will easily break today's record even if a substitution needs to made w/ Varina co-op if the ASOS becomes too unrepresentative. SBY has a decent chc at tying or breaking their record which like RIC is only 95F today. Dew points likely drop off a few degrees during the hottest part of the aftn so heat indices will mostly be ~100F. Any cirrus clears this evening with mostly clear skies tonight, with overnight lows temperatures ranging from the upper 60s across interior rural areas to 70-75F closer to the coast and over urban areas. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 350 AM EDT Monday... Dry and very hot weather continues through Thurs as the upper ridge remains in control, peaking Tues. High Tues and Wed will continue to mostly be in the upper 90s inland and in the low-mid 90s along the coast. Locally, a few sites such as the RIC ASOS have a chance at reaching 100F Tue and Wed given the lack of rainfall (only 0.33" of rain measured there since August 11th). When areas go several weeks with little rainfall, the soil dries deep enough that when a dry airmass comes overhead, diurnal mixing can be locally maximized, allowing temps to overperform. This is especially exacerbated at sites in the vicinity of larger airport terminals/runways, etc., occurring at rural co-op sites as well but w/ a lower magnitude. In any case, it will be very hot CWA- wide with highs 10-15F above average and additional daily record highs may be set (see Climate section for additional information). Heat indices will not be too much above actual air temperature given deep mixing allowing dew points to drop a few degrees during the highest temperatures of mid- late afternoon. Expect max heat indices of 100-104F both days. Will have to monitor mainly NE NC and potentially areas along the Ches Bay for potential Heat Advisories (up to 107F heat indices) both days given locally higher dew points. Lows in the upper 60s W to lower 70s E both Tues and Wed nights. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 405 AM EDT Monday... The upper level ridge breaks down Thurs as an upper level trough dives SE from the Great Lakes into the Appalachians. This trough is now expected to linger over the area through the weekend, allowing for unsettled weather from Thurs through Sun with the greatest chance for rain on Fri and Sat. PoPs increase to 15-30% Thurs in the Piedmont, increasing to 40-45% Fri into Fri evening, 40-50% Sat into Sat evening, and 25-30% Sun. Cannot rule out an isolated shower/storm Mon but chances will be dwindling (15-25%). This could bring some much needed rain to the area with the GFS/CMC indicating the potential for a couple inches of rain through the weekend. The Euro shows less (mainly 0.25-0.5"). With the ridge breaking down, temps will finally cool off back into the 80s by the weekend. Highs in the mid-upper 90s inland and low-mid 90s along the coast Thurs, upper 80s W to lower 90s for most Fri, mid-upper 80s Sat, and low-mid 80s Sun and Mon. Lows in the upper 60s W to low-mid 70s along the coast Thurs night, mid 60s W to lower 70s along the coast Fri night, mid 60s W to upper 60s to near 70F E Sat night, and lower 60s NW to upper 60s SE Sun night. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... As of 650 AM EDT Monday... Cirrus move in from NW to SE this morning and linger through the day near the coast. However, expect mainly thin cirrus with skies remaining mostly clear. Any clouds dissipate tonight. Some very patchy fog is early this morning should dissipate over the next hour and remain away from the terminals. Winds remain light and variable today, becoming NW 5-8 kt this afternoon, and then become light and variable again tonight. Outlook: High pressure remains in control through most of the week. VFR conditions expected through at least Thu with PoPs increasing by Fri-Sat. && .MARINE... As of 300 AM EDT Monday... Prevailing sub-SCA conditions are expected through the week. A very weak pressure gradient through much of the week should yield wind speeds mostly 10 kt or less with varying wind direction. Easterly swell of around 4 ft with a 10-13 second period continues to impact the coastal waters. Seas will remain around 3-4 ft through Tuesday due to that long period swell. Seas slowly subside to 2-3 ft by late Wed. Waves on most of the bay/rivers should remain 1 ft or less through the middle of the week. Waves of around 2 ft are expected at the mouth of the bay from today-Wed. Rip Currents: Given continued easterly long period swell, the risk of dangerous rip currents forming will remain HIGH at all area beaches today. Nearshore waves in the surf zone are expected to be 3- 4 ft. Will increase the forecast rip risk to HIGH on Tuesday as well given that the latest 00z NWPS guidance does not show much decrease in swell height until Wed. && .CLIMATE... Record high temperatures are possible today/Mon-Thu at long- term climate sites. For reference, Septembers with the most days reaching 90/95/100 degrees are also listed. *also in earlier years * Date: Mon 9/4 Tue 9/5 Wed 9/6 Thu 9/7 * RIC: 95/1970 100/1954 102/1954 103/1954 * ORF: 96/1985 97/1985 98/1899 98/1954 * SBY: 95/1944 95/1961 95/1983 95/1943 * ECG: 98/1944 96/1985 98/1954 95/1985 Most 90F+/95+/100+ Days in September: 90F+ Days 95+ Days 100+ Days * RIC: 15 in 1970 9 in 1930 3 in 1954 * ORF: 10 in *1930 6 in 1985 2 in 1895 * SBY: 16 in 1930 4 in 1930 1 in 1932 * ECG: 10 in *2018 7 in 1985 (none) * Note that if RIC ASOS is 3 or more degrees for high temperature in comparison to the nearby Varina co-op (where it has been similarly dry), a substitution may be made due to the ASOS being unrepresentative. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...LKB/RMM NEAR TERM...LKB/RMM SHORT TERM...LKB/RMM LONG TERM...RMM AVIATION...RMM MARINE...ERI CLIMATE...