Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
493 FXUS61 KLWX 010110 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 910 PM EDT Sun Jun 30 2024 .SYNOPSIS... A cold front will push through this evening. A strong area of high pressure settles over the area Monday and Tuesday before drifting offshore the second half of the week. A warm front nears the region by mid-week yielding a warming trend. && .NEAR TERM /THROUGH MONDAY/... A cold front extends from far northeastern Maryland, to just northwest of Washington DC, and southwest into the central Shenandoah Valley. Ahead of this cold front, clusters of strong to severe thunderstorms have developed and are moving to the southeast. Multiple severe thunderstorm warnings and special marine warnings are in effect for another hour or so. To the northwest of this front, northwest to north winds have developed and will continue through the rest of the evening and into the overnight. The main threat with the severe thunderstorms will be wind gusts 60 to 80 mph with quarter to golf ball size hail. An isolated tornado or waterspout can`t be ruled out. Showers and thunderstorms may not clear far southern Maryland and the central Chesapeake Bay until around midnight or shortly thereafter. Cooler and much drier air will be ushered into our CWA overnight behind the cold front. Lows will drop back into the mid 50s to mid 60s, with 40s possible in the higher elevations. Upper trough axis will pass through Monday as strong (1025 mb) surface high pressure build in from the Great Lakes. This will result in gusty northerly winds through the day and very comfortable conditions for early July standards. Highs will be in the upper 70s to lower 80s with dew points ranging from the upper 40s to mid 50s. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... Dry and cooler conditions continue with diminishing winds Monday night with the high passing to the north. Lows in the 50s will be common, but the I-95 corridor likely stays in the 60s. With the ridge axis progressing to the east Tuesday, it will be a little milder, and there may be some extra cloud cover at times. Dew points will remain in the 50s though, resulting in continued comfortable weather. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Mostly dry conditions are expected Wednesday as high pressure holds on before scooting further offshore with large disturbance approaching from the west. Warm, moist air will build in during the day on Wednesday, allowing a warm up compared to the previous few days with highs in the upper 80s to low 90s. Winds will be elevated out of the SSE, gusting to 20 knots at times during the afternoon. Overnight lows fall into the upper 60s to low 70s for most areas. A large area of low pressure center over the central Canadian provinces will slowly track further east along a secondary low across the heart of the CONUS. Showers and thunderstorm chances will continue from July 4th holiday through the early part of the weekend with renewed PoPs each afternoon and evening. Should the forcing became more sufficient locally and convective parameters increase, strong to severe thunderstorms may be possible during the period but there remains a lot of uncertainty in this. The heat continues through the remainder of the week with highs in the low to mid 90s and heat indices reaching triple digits. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Strong to severe thunderstorms have cleared MRB, CHO and IAD terminals. DCA, BWI and MTN will be cleared from showers and thunderstorms between 0130z and 0230z Monday. Northerly winds will take precedence overnight into Monday. VFR conditions will prevail after storms exit. As the ridge of high pressure pushes off toward the New England coast, winds shift to east-southeasterly on Tuesday, before becoming southerly Tuesday night. VFR continues. VFR conditions are expected Wednesday and Thursday for the terminals. Showers and thunderstorms return Thursday, especially further west, so some isolated instances of sub-VFR conditions is not completely out of the question for the holiday period. && .MARINE... Special Marine Warnings are in effect over large pieces of the Chesapeake Bay and Tidal Potomac for another hour or so. Otherwise, once the cold front moves southeast of the region, small craft advisories will be the main story into Monday. The small craft advisories may need to be extended into Monday evening for portions of the waters. Winds turn more east- southeasterly on Tuesday with high pressure to the north, staying below advisory thresholds. SCAs are expected Wednesday as high pressure exits to the east and incoming low pressure and associated frontal features approach from the west. Winds diminish by July 4th but SMWs may be needed Thursday afternoon for any strong showers or thunderstorms that cross the waters. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 2 PM EDT Monday for ANZ530-531-535- 536-538-539. Small Craft Advisory until 10 PM EDT this evening for ANZ532>534-537-540>543. Small Craft Advisory from midnight tonight to 6 PM EDT Monday for ANZ532>534-537-540>543. && $$ SYNOPSIS...ADS NEAR TERM...ADS/KLW SHORT TERM...ADS LONG TERM...ADM AVIATION...ADS/KLW/ADM MARINE...ADS/KLW/ADM