Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 261941 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 341 PM EDT Tue Mar 26 2024 .SYNOPSIS...
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A cold front will approach the area tonight into tomorrow. An area of low pressure will develop along the front and track off to our northeast on Thursday into Friday. High pressure will build to our south on Friday. Multiple weak disturbances will track across the area this weekend into early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Current surface analysis shows a strong area of low pressure tracking across the Upper Peninsula of Michigan. Water Vapor imagery shows a broad upper trough over the Great Lakes, as well as much of the center of the country, with a pronounced lead shortwave attendant to the aforementioned area of low pressure. A large fetch of moisture is steaming northward across the Appalachians and Ohio Valley downstream of the upper trough, with a fairly expansive stratiform rain shield in place from Georgia northward into Ontario. The shortwave and attendant area of low pressure will lift toward the north-northeast later this afternoon into tonight, with the bulk of the large scale ascent moving across the Great Lakes into southern Canada. As a result, the shield of precipitation currently on radar off to our west will tend to weaken and thin out as it slowly spreads eastward through the rest of the day today into tonight. Rain will move into the Alleghenies over the next couple hours, and slowly expand eastward/start to fall apart through the evening. A few sprinkles or light showers may be possible anywhere overnight, but conditions should remain dry the bulk of the time. Some patchy fog and/or drizzle may form toward daybreak within light southeasterly flow. It will be a mild night with the thick cloud cover in place. Low temperatures in most locations will be in the 40s.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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Rain will be on the increase tomorrow morning, especially to the east of the Blue Ridge. Chances for thunderstorms are low, but a few elevated storms can`t be ruled out along and east of the I-95 corridor late tomorrow morning into early tomorrow afternoon. Overall, rainfall amounts should be fairly light through the day tomorrow, with just a few tenths of an inch expected. Less rainfall is expected to the west of the Blue Ridge, but cloudy conditions will persist. Winds will remain light out of the southeast, and high temperatures will generally be in the 50s to the east of the Blue Ridge, with 60s further west. Spread in model guidance begins to increase tomorrow night as a slow moving cold front progresses eastward across the area and an area of low pressure develops along the front to our south. The majority of 12z guidance has continued a southeastward trend with the precipitation. Some solutions (such as the HRRR) have little to no precipitation along and west of I-95 tomorrow night, while others (such as the 12z 3km NAM) still show substantial precipitation amounts. Most solutions now have the heaviest rainfall confined to southern Maryland. The front will continue to slowly progress eastward on Thursday as low pressure deepens and tracks northeastward along the Carolina Coast. Chances for rain will continue through at least the morning hours and potentially into the afternoon as well, especially to the east of the Blue Ridge. Conditions should finally dry out by Thursday night.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/...
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Drying conditions will settle in on Friday in the wake of a low pressure system that will have impacted the area over the previous few days. Pressure gradients will remain tight across the area as a result of the low to the north and high pressure building in across the southeastern states. Gusts may reach Wind Advisory criteria, especially along the higher terrain. Aside from the winds, expect mostly sunny skies with high temperatures in the 50s to low 60s (warmest across central VA and southern MD). The area of high pressure will continue to shift further south late Friday night into early Saturday, with a warm front moving in from the west. This front is expected to stall around the Mid-Atlantic and may allow for periods of rain and increasing clouds for the weekend. With warm air advection in place, expect high temperatures to rise into the mid to upper 60s on Saturday to even low 70s by Sunday across a large portion of the area. It will be slightly cooler across the higher elevations with mid to upper 50s expected. Should the front continue to linger around the area on Monday, rain chances may continue. Temperatures will be likely be closer to just above normal for this time of year. Rain chances increase going into midweek next week as an another disturbance impacts the area from the west.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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VFR conditions are ongoing at most terminals this afternoon, but an MVFR deck is holding at MTN. This MVFR deck will slowly move westward as southeasterly flow develops, impacting BWI next, and then all terminals by later this evening. Conditions should drop to IFR at all terminals tonight, and remain IFR through the day tomorrow, and likely even much of tomorrow night into Thursday. Improvement back to VFR ceilings is expected Thursday afternoon into Thursday night. A few sprinkles or light showers may be possible starting this evening, but most of the overnight hours should remain dry. Some patchy fog and/or drizzle may also start to form during the second half of the night. Steadier rainfall is expected tomorrow morning at all terminals, with the steady rain lingering through much of the afternoon at DCA, BWI and MTN. Chances for thunder during the late morning/early afternoon hours are non-zero, but far too low to include in the TAFs. Precipitation may redevelop tomorrow night and continue thorough much of Thursday as a coastal low develops off to our east. There is some east/west uncertainty with respect to where this precipitation shield sets up. Locations further east will have greater chances for steady rain. Winds will generally be out of the southeast through tomorrow, before turning out of the northwest on Thursday. VFR conditions are expected Friday with gusty northwest winds of 25 to 35 knots possible. A weak front may approach Saturday and provide a chance of showers and perhaps some wind gusts to around 20 kt, but confidence remains low in CIG/VIS restrictions.
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&& .MARINE...
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Winds have turned out of the southeast to east this afternoon and are relatively light at around 5-10 knots. There may be a slight uptick in the winds this evening to around 15-20 knots for an hour or two. Winds will remain sub-SCA out of the southeast through the day tomorrow. Winds will turn northerly tomorrow night, and then northwesterly during the day on Thursday. Small Craft Advisories may be needed for the waters in northwesterly flow on Thursday. Gusty northwest winds are expected Friday with a tightening pressure gradient over the waters. Small Craft Advisories appear likely at this time with some chances for potential gale-force winds during the day. Advisories may continue on Saturday before the gradient weakens over the following few days.
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&& .TIDES/COASTAL FLOODING...
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Water level anomalies are around 1.5-2 feet above normal this afternoon. While the rate of increase in anomalies has slowed, models indicate another half to three quarters foot rise is possible through early Wednesday as onshore flow continues. Made subtle tweaks to the overall watches/warnings/advisories. The primary message remains the same that fairly widespread minor to locally moderate flooding is expected through the middle of the week. Water levels will begin falling Thursday after a front pushes through.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until 7 AM EDT Wednesday for DCZ001. Coastal Flood Watch from Wednesday morning through Wednesday afternoon for DCZ001. MD...Coastal Flood Advisory until 3 PM EDT Wednesday for MDZ011-016- 508. Coastal Flood Warning until noon EDT Wednesday for MDZ014. Coastal Flood Warning until 6 AM EDT Wednesday for MDZ017. Coastal Flood Advisory until 7 PM EDT Wednesday for MDZ018. VA...Coastal Flood Advisory until 3 PM EDT Wednesday for VAZ054-057. Coastal Flood Advisory from 7 PM this evening to 3 PM EDT Wednesday for VAZ053-055-527. WV...None. MARINE...None.
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&& $$ SYNOPSIS...KJP NEAR TERM...KJP SHORT TERM...KJP LONG TERM...ADM AVIATION...KJP/ADM MARINE...KJP/ADM TIDES/COASTAL FLOODING...CPB

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