Area Forecast Discussion
Issued by NWS Sterling, VA

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606 FXUS61 KLWX 150228 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 928 PM EST Wed Feb 14 2018 .SYNOPSIS...
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Very mild weather will persist through Thursday night. A cold front will then cross the area Friday morning. An area of low pressure will affect the area Saturday night. High pressure will return briefly Sunday into Monday before another frontal system approaches for the middle part of next week.
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&& .NEAR TERM /THROUGH THURSDAY/...
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Warm advection will continue through the overnight hours with scattered rain showers spreading eastward. Rainfall amounts will be light, perhaps up to one tenth of an inch in places. These rain showers will move across the Chesapeake Bay and the Delmarva later in the overnight toward Thursday morning. Some low stratus clouds could ensue later overnight with a chance for some patchy fog late and early Thursday. As for the remainder of Thursday, some weak upper level energy will slide across the region and bring a continuation of cloud cover during the day. Light to moderate southwesterly winds will usher in milder Spring-like air into the region, resulting in high temperatures Thursday pushing 70 degrees in most places. Dewpoint temperatures will also be on the rise Thursday with values pushing through the 40s into the lower 50s. This increase in warmth and moisture will aid in fueling the next batch of rain showers later in the day and primarily along the Appalachian Front and adjacent to the Mason-Dixon region.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
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Rain showers will continue Thursday night into Friday morning due to a strong cold front that will move across the area Friday morning. Rainfall amounts with this second round are expected to be in the 0.25 inch in southeast MD to 2.5 inches in the far NW. WPC excessive rainfall outlook has area west of I-81 in a marginal threat and western Alleghany county in a slight risk. FFG from the MARFC is very low over western Alleghany for some unknown reasons. This area missed the heavy rainfall that fell this past weekend. Showers will taper off by late Fri. Expect calendar highs to occur just before fropa late Thu night with temperatures dropping all day Fri. Strong high pressure will build from west to east into the region behind the frontal passage Friday afternoon through Friday night. Thus, southwest winds will shift to northwest and become gusty. Temperatures will also fall steadily and quickly Friday morning through Friday night.
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&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Saturday starts out dry as high pressure centered over New England moves east and a front stalls to our south. A wave of low pressure will track through the frontal boundary and will impact us later on Saturday. Guidance have become in better agreement to overspread the region with precipitation on Saturday afternoon into the night with rain and snow possible. The uncertainty remains on temperatures at the low and mid levels, with the potential for sleet, freezing rain as well... and even if ground temperatures will be cold enough to allow for accumulations. The track of this system will impact the type of p-type observed over our CWA. At this moment QPF amounts are between a quarter and three quarters of an inch. In summary, there is the potential for wintry precipitation on Saturday afternoon into the night but it is too uncertain to determine local impacts. High pressure builds overhead on Sunday and remain in control into Monday as it moves offshore. A warm front will lift north on Monday night and a cold front will stall over our region with waves of low pressure moving through it, therefore unsettled weather expected Monday night into Wednesday. Temperatures will be warm, so no concerns about wintry precipitation at this moment. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Developing MVFR cigs and vsbys late tonight at all TAF sites with potential for IFR conditions at KMRB and KMTN late tonight. Conditions improve rapidly Thu morning. VFR conditions are expected during the first part of the day Saturday. Conditions could rapidly become sub-VFR Saturday afternoon and into the night with precipitation overspreading over the terminals. There are concerns with p-type. VFR conditions return Sunday and into Monday. && .MARINE...
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Winds are expected to strengthen Thursday with SCA conditions expected Thursday through Friday night. Winds are expected to be below SCA criteria from Saturday into Monday, so no small craft advisory expected.
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&& .CLIMATE... Unseasonably warm weather is expected on Thursday. While temps will be over 20 degrees above normal, it will be difficult to top the record highs in Baltimore and Washington. However, the record highs at Dulles could be smashed. Below are the current record highs for Thursday February 15: SITE RECORD MAX RECORD MIN DCA 77 in 1949 52 in 1909 BWI 77 in 1949 51 in 1949 IAD 68 in 1982 44 in 1984 and 1967 && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 10 AM to 6 PM EST Thursday for ANZ530>543. && $$ SYNOPSIS...KLW NEAR TERM...KLW SHORT TERM...KLW LONG TERM...BJL AVIATION...BJL/KLW MARINE...BJL/KLW CLIMATE...

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