Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 161443 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1043 AM EDT Mon Apr 16 2018 .SYNOPSIS... A strong cold front will cross the area later this morning. Weak high pressure will gradually build back in for Tuesday and Wednesday before another low pressure system crosses the region Thursday. High pressure builds again over the region for the latter part of the week. && .NEAR TERM /THROUGH TONIGHT/...
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Cold front along with main slug of rain and thunderstorms has pushed to the northeast. Scattered showers beneath the upper trough axis remain, and will continue to pivot through the area through much of the day. It will turn cooler and breezy by mid afternoon as the surface cold front pushes east and high pressure builds into the region from the Ohio Valley. Freezing temperatures are possible over parts of the Shenandoah Valley tonight, but uncertainty remains. Will await later model guidance before making a decision with the Freeze Watch.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... Quite cool and breezy especially for mid April as area remains under cyclonic flow aloft associated with low pressure over the St. Lawrence river. Dry conditions expected except for some upslope precipitation over the Appalachians. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Next frontal passage is expected Thursday with a chance of showers. Precip will be significantly less with this system due drier westerly sfc wind trajectories and not enough moisture return. Quiet weather expected for the latter part of the week as high pressure builds in. && .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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Conditions gradually improve to VFR through the remainder of today, but still bkn cigs 030-040 and breezy (NW flow). VFR expected to remain with breezy conditions through Tuesday evening. Winds become light as high pressure moves overhead Wednesday. Frontal passage expected Thu with sct showers and gusty W winds (30+ kts possible).
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&& .MARINE...
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SCA through Tuesday evening as pres gradient remains tight. SCA likely again Thursday with gales possible as low pressure passes across the Great Lakes resulting in increased westerly flow.
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&& .HYDROLOGY... Flash flood warning in effect for the Cameron run in Alexandria and Fairfax county where river gauge indicated the creek had risen above flood stage. A flood warning is also in effect for the South Branch Potomac River in Franklin, WV. && .TIDES/COASTAL FLOODING... Minor coastal flooding is expected at most sites, perhaps even moderate flooding at Annapolis and Straits Point. We`ll reevaluate situation later this morning and upgrade to a warning if necessary. && .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until 1 AM EDT Tuesday for DCZ001. MD...Freeze Watch from late tonight through Tuesday morning for MDZ003>005. Coastal Flood Advisory until 11 PM EDT this evening for MDZ014. Coastal Flood Advisory until 5 AM EDT Tuesday for MDZ016. Coastal Flood Advisory until 7 AM EDT Tuesday for MDZ017. Coastal Flood Advisory until 6 AM EDT Tuesday for MDZ018. Coastal Flood Advisory until 4 PM EDT this afternoon for MDZ508. Coastal Flood Advisory until 10 PM EDT this evening for MDZ011. VA...Freeze Watch from late tonight through Tuesday morning for VAZ025>031-507-508. Coastal Flood Advisory until 5 AM EDT Tuesday for VAZ057. Coastal Flood Advisory until 1 AM EDT Tuesday for VAZ054. WV...Freeze Watch from late tonight through Tuesday morning for WVZ051>053. MARINE...Small Craft Advisory until midnight EDT Tuesday night for ANZ530>532-535-536-538>540. Small Craft Advisory until 6 AM EDT Wednesday for ANZ533-534- 537-541>543.
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&& $$ SYNOPSIS...LFR/DHOF NEAR TERM...LFR/DHOF SHORT TERM...LFR LONG TERM...RCM AVIATION...RCM/LFR/DHOF MARINE...RCM/LFR/DHOF HYDROLOGY...LFR TIDES/COASTAL FLOODING...LFR

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