Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 160218 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 918 PM EST Fri Dec 15 2017 .SYNOPSIS... High pressure will build south of the area through early Sunday. A weak backdoor cold front will stall over the area Sunday then lift north as a warm front on Monday. A surface trof will move across the area Tuesday. Weak high pressure builds over the area during the second half of next week. && .NEAR TERM /THROUGH SATURDAY/... Temperatures have dropped significantly this evening where skies are clear and winds are light. Stratocumulus are seen over eastern WV and western MD where winds have picked up from the west and are gusting over 25 mph. Temperatures in those areas have jumped dramatically from the low 20s to near freezing in a short period of time as seen at Martinsburg. Temperatures will bottom out in the upper teens east of the mtns in the next few hrs but will likely rise overnight as winds strengthen and mixing increases. There could be a few snow showers over the mtns overnight as upslope flow increases potentially dropping as much as half inch of snow. Any freezing fog this evening is expected to dissipate by midnight as winds strengthen and mixing increases. Overall, cold and breezy overnight. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... High pressure will remain to our south for Saturday and Saturday night. A southwest flow around the high will usher in somewhat milder conditions Saturday afternoon after a chilly start. Max temps will be in the 40s for most areas. High pressure will move offshore Sunday and a southerly flow will usher in more moisture and somewhat milder conditions. Max temps will be in the 40s for most areas with lower 50s in central Virginia. An upper-level disturbance will pass through late Sunday and Sunday night. A few showers are possible...but forcing from this system will be weak so any precipitation that does fall will be light. && .LONG TERM /MONDAY THROUGH FRIDAY/... Mild conditions expected during the long term period with dry conditions on Monday as we sit between two boundaries and southerly flow settles over our region. Some showers could develop over higher elevations later on Monday and into Tuesday, but still expecting mainly dry conditions over our CWA. A cold front approaches Tuesday night increasing PoPs over our area, but QPFs are not impressive. High pressure settles in behind the front Wednesday into Friday with winds become northwesterly... then becoming southwesterly Thursday into Friday as high pressure moves offshore. Temperatures will be above normal in general with highs reaching the 50s and 60s in most locations, except on Wednesday. Low temperatures will be in the 30s and 40s, but colder on Wednesday night. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR conditions are expected tonight through Sunday morning. A few showers are possible later Sunday and Sunday night along with MVFR conditions...but confidence in precipitation is low at this time. VFR conditions expected Monday into Wednesday. Maybe sub-VFR conditions on Tuesday night as showers could move through the terminals. Gusty winds expected on Wednesday, up to 20 kt. && .MARINE... Low pressure will move out to sea tonight. A Small Craft Advisory is in effect for the Maryland Chesapeake Bay south of Drum Point and the lower Tidal Potomac River...closer to the gradient. High pressure will build to the south for tonight through Saturday...but a tightening gradient will result in SCA conditions. The gradient will subside Saturday night and Sunday. A weak disturbance will pass through Sunday night. Winds are expected to stay below small craft advisory threshold Monday into Tuesday. Winds could increase Tuesday night into Wednesday behind a front, requiring a small craft advisory over the waters. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from midnight tonight to 7 PM EST Saturday for ANZ530>534-537-539>541-543. Small Craft Advisory from noon to 7 PM EST Saturday for ANZ535- 536-538-542. && $$ SYNOPSIS...BJL NEAR TERM...LFR SHORT TERM...BJL LONG TERM...IMR AVIATION...BJL/IMR MARINE...BJL/IMR is the U.S. government's official web portal to all federal, state and local government web resources and services.