244 FXUS61 KLWX 080229 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 929 PM EST Tue Nov 7 2017 .SYNOPSIS... Low pressure will move eastward along a stationary front draped across the Carolinas this afternoon and tonight, and out to sea Wednesday. A cold front will drop south through the area Thursday night followed by high pressure for the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... After dragging its feet getting out late today, the rain is now beginning to exit quickly east and south. Expect that to continue with cooling temps. Incorporated some of the latest LAMP guidance for temps overnight. Lows at or a little below freezing for the Appalachians and other spots over 2000 feet. Around 40 for the cities. Still should be mainly overcast by sunrise. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... The cold front will remain sufficient far south Wednesday through Thursday to permit a mainly dry forecast through this period. Am holding onto chance of rain across central Virginia/southern Maryland Wednesday to account for a slower departure, but have incorporated a 50/50 blend of GFS and NAM MOS guidance from the 18z runs which pushes that even a bit further south than the 12z runs had it. Otherwise, skies will average out to be partly cloudy...clearest to the north...with relatively light north flow. Winds will be lighter Wednesday night-Thursday as a narrow wedge of high pressure works east into the area. Am not straying far from a model blend for temperatures...which has been verifying quite well. That means mid 40s-lower 50s Wed, 30s Wed night, and warming a pinch into the 50s for Thu. An arctic front crosses the area Thursday night. Precip chances hold to the north of the area, nearer the mid-upper level dynamics. But a blast of cold advection suggests that a surge of wind will accompany the frontal passage. Momentum transfer indicates 25-30 kt gusts possible; may go a bit on the conservative side considering the overnight event timing. Subfreezing temps likely west of the Blue Ridge and along the Mason-Dixon line. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Friday main story is the strong cold advection behind a front that will keep temperatures 10 to 15 degrees below normal as a high pressure builds in over the region. High temperatures Friday will be be around the low to mid 40s east of the Blue Ridge, while it will be reach near 40 or below west of it. Low temperatures overnight will be in the 20s for most of our CWA, maybe near 30 in the metros and near the Chesapeake Bay, upper teens in the western valleys. Saturday dry conditions continue while high pressure continues to move east. High temperatures will be a close repeat of Friday. Overnight lows will be slightly warmer than Friday night as southerly flow settles in. Sunday starts out dry as high pressure moves offshore the New England coast. A cold front approaches from the west increasing PoPs over our area Sunday afternoon and into the evening. Some upslope showers may remain into Monday. High pressure returns Monday and into Tuesday. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... IFR should prevail through the evening, before gradually lifting overnight to MVFR. The stalled front to the south of the area will inch further south, which will allow for slightly drier air to infiltrate from the north. Anticipate VFR by the morning push Wed, which should continue through Thursday. A reinforcing cold front Thursday night will provide a blast of winds, with 25-30 kt north/northwest gusts common overnight. Do not anticipate any flight restrictions. VFR/dry conditions expected Friday into early Sunday with high pressure keeping dry conditions over the terminals. However, gusty conditions expected Friday and Friday night until the high builds overhead. Sub- VFR conditions possible Sunday afternoon and into evening with cold front increasing the probability of precipitation over the terminals. && .MARINE... Small craft advisory winds or close to it this evening and tonight across the meso observations over the Bay and tidal rivers. Expect to trim that back to just the lower MD Bay and Potomac for the afternoon. Winds will be diminishing overnight Wednesday into the day on Thursday. A reinforcing cold front will be crossing the water Thursday night, which will bring another round of potential Small Craft. Small Craft Advisory conditions should continue into Friday night with wind gusts reaching 20 to 25 kts at times. Wind gusts will diminish Saturday and remain below criteria into Sunday. && .TIDES/COASTAL FLOODING... ESTOFS/ETSS in good agreement through the period so blended the two for this forecast, which indicates rising waters levels through late this week. This is due to northerly flow that traps and prevents water from escaping the mouth of the Chesapeake Bay. The next tide cycle tomorrow morning is astronomically the lower of the two, but after that minor flooding should once again become prevalent. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 1 PM EST Wednesday for ANZ530>533- 535-536-538>542. Small Craft Advisory until 1 AM EST Thursday for ANZ534-537- 543. && $$