000 FXUS61 KAKQ 191653 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 1153 AM EST Tue Feb 19 2019 .SYNOPSIS... High pressure builds across the region today. Unsettled conditions return tonight into Wednesday as the next storm system moves northeast from the Gulf of Mexico. A frontal boundary then stalls over the southeast and mid Atlantic states through Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 1155 AM Tuesday... Going forecast on track, with no major adjustments needed at this time. Slowed cloud onset with mainly clear sky over the NE 2/3 of the forecast area. Timing for light precip onset late this evening still on track, with increasing cloud trend for mid to late aftn through the evening still looking reasonable. High-res NAM Conest and Time-lagged HRRR doing a good job handling onset of precipitation upstream, and will generally follow this blend along with going forecast for the evening hours. Becoming partly to mostly cloudy late with highs mainly in the low to mid 40s. Previous discussion as of 700 AM Tuesday... Current wv imagery shows a deep trough over the Intermountain West and Desert Southwest, and another trough over ern Canada. A broad ridge is situated over the subtropical wrn Atlantic, with strong WSW flow aloft over the Mid-Atlantic region. At the surface, 1036mb high pressure over the ern Great Lakes is building into the region. Cirrus continue to stream overhead but have thinned some early this morning, with temperatures generally 30-35F, with upper 30s in coastal SE VA/NE NC. High clouds will continue to stream overhead today with strong flow aloft continuing and also increasing moisture aloft as low pressure emerges out of the nrn Gulf of Mexico. Partly to mostly cloudy and cool today with highs in the 40s. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... As of 410 AM EST Tuesday... 1036mb high pressure becomes centered over New England later tonight. Meanwhile, low pressure will push into the Deep South, with moisture streaming well NE of the low. Initially cool and dry this evening, with temperatures dropping into the 30s, and potentially upper 20s over the MD Ern Shore. The moisture profile will thicken after midnight inland W of the Bay as the initial push of WAA aloft arrives. Thermal profiles should initially support mostly snow, with the exception of the far SE where either a snow/sleet or rain/sleet mix is likely and all rain at the immediate coast. 850mb WAA strengthens after 12z Wednesday with 40-50kt of wind at this level by 15-18z Wednesday. Therefore, 850-700mb thickness values will rise very quickly while 1000-850mb thickness values will be slower to increase as surface high pressure remains in vicinity of srn New England. Therefore, expect snow to quickly transition to sleet then freezing rain throughout the morning, with all rain pushing into s-central VA after 12z/7am Wednesday, and then to the I- 85/US 360 corridor after 15z/10am Wednesday. Warm air aloft will continue to deepen during the aftn Wednesday, while the cool surface layer will slowly shallow. Most areas will rise above 32F by mid- late aftn, with the exception of the far NW where some pockets of freezing rain could continue. Snow accum is forecast to range from a T-0.5" from the SW Piedmont to the VA Ern Shore, with 1-2" from the central Piedmont toward the RIC metro and most of the MD Ern Shore, and 2-3" for the NW Piedmont, n-central VA, and Dorchester MD. Ice accum is forecast to range from a few hundredths of an inch for the I-95 corridor and 0.1-0.15" over the Piedmont. Winter Weather Advisories have been issued from the Piedmont to the RIC metro to the Nrn Neck and MD Ern Shore (not the MD beaches at this time). This could be expanded father S eventually for impact as it will impact the morning commute Wednesday. Forecast highs Wednesday range from the low 30s NW to the upper 30s/low 40s central, and low 50s far SE. Mostly rain by Wednesday night (albeit a cold rain NW) with temperatures remaining rather steady through the night. A cold front aloft slowly pushes through the area Thursday with the highest rain chances shifting SE. Temperatures will be challenging Thursday and will largely be dictated by whether or not any clearing can occur by aftn. Temperatures aloft will be quite warm (6-10F) at 850mb, but the low-level cool airmass my not completely scour out if clouds hold strong. For now, forecast highs are mainly in the 50s. Total liquid QPF for the event ranges from 0.75" S to 1.25" N. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 340 PM Monday... High pressure settles into the Upper Midwest/Great Lakes Thu night as a cold front stalls over AL/GA/SC. A trough of low pressure will develop along the stalled front on Fri as high pressure slowly moves toward the Northeast US. However, the bulk of the RA is expected to remain S of the CWA from 00z Fri-00z Sat. Kept slight chc-chc PoPs for central/srn zones as a few brief periods of light rain are possible during this timeframe. However, an area of steady light- moderate rain will quickly overspread the entire region (from SW to NE) from 06z-18z Sat as a deep upper trough over the wrn CONUS deamplifies/starts to move E toward the Plains/Midwest. At the same time, a warm front lifts N toward the region, allowing a CAD/wedge pattern to set up over the CWA late Fri-Sat. Expect Saturday to be a cool, rainy day across much of the area. The warm front lifts N of the CWA Sat night as a stronger area of sfc low pressure deepens as it tracks from the Plains to the Midwest. Steady rain is expected to give way to scattered showers Sat night-Sun as the region goes into the warm sector. Rain chances finally decrease by Sun night as the area of sfc low pressure tracks from the Midwest to SE Canada and the associated cold front crosses the region. Drier (but still mild) Mon/Mon night as sfc high pressure briefly settles to our N. Lows Thu night will range from the mid 30s N to the low-mid 40s S. Highs Fri will be in the mid 40s to around 50. Lows fall into the mid 30s-low 40s Fri night. Highs Sat will range from the mid 40s NW to mid 50s in coastal NE NC. Warmer on Sun as forecast highs are in the low 60s-low 70s (coolest N/NW, warmest in NE NC). Cooler (but still mild) on Mon with highs in the low 60s in most areas (except for mid-upper 50s NW/on the Ern Shore). && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 700 AM EST Tuesday... High pressure is building in from the NW as of 12z and will prevail over the region through today. VFR conditions beneath cirrus are expected through this evening, with a light N wind becoming NE later this aftn into the evening. Conditions deteriorate later tonight into Wednesday morning as low pressure approaches from the SW. A period of SN or SN/PL is expected at RIC/SBY later tonight into early Wednesday morning, before transitioning to FZRA at RIC, and then changing to RA at both sites by Wednesday aftn. PHF may briefly begin as SN/PL or RA/PL before changing to RA, with RA expected at ORF/ECG. Cigs are expected to fall to IFR Wednesday into Wednesday night as a warm moist airmass aloft overruns a cool layer at the surface. Vsby restrictions are expected as well, associated with pcpn and BR. RA is expected to continue into Thursday, before high pressure briefly returns Thursday night into Friday. Low pressure, and more rain and flight restrictions are expected Friday night into Saturday. && .MARINE... As of 250 AM EST Tuesday... Lo level CAA continuing to wane this morning as sfc hi pres from the NNW builds towards the local waters. SCAs coming down...initially on the lower Bay and central Bay early...then followed by the lower Bay/ocean and sound by late morning/midday. Primary lo pres tracks into the Great Lakes tonight-Wed...w/ a weaker secondary lo pres riding NE near the mid-Atlantic coast. Potential for another round of SCA conditions Wed afternoon/night...esp for the coastal waters and lower Bay/James due to onshore flow. Conditions remain unsettled through the end of the week as yet another low pressure system affects the area. && .HYDROLOGY... Flood Warning continues for the Meherrin at Lawrenceville. River level expected to reach flood stage later tonight, before dropping below flood stage midday Wed. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Winter Weather Advisory from 6 AM to noon EST Wednesday for MDZ022>024. Winter Weather Advisory from 6 AM to 3 PM EST Wednesday for MDZ021. NC...None. VA...Winter Weather Advisory from midnight tonight to 9 PM EST Wednesday for VAZ048-509-510. Winter Weather Advisory from midnight tonight to 6 PM EST Wednesday for VAZ061-062-069-511-512-515. Winter Weather Advisory from midnight tonight to 3 PM EST Wednesday for VAZ060-065>068-513. Winter Weather Advisory from 3 AM to 6 PM EST Wednesday for VAZ064-075>078-517-519-521-522. MARINE...Small Craft Advisory until 1 PM EST this afternoon for ANZ632>634-656-658. && $$ SYNOPSIS...AJZ/MAM NEAR TERM...AJZ/MAM SHORT TERM...AJZ/MAM LONG TERM...ERI AVIATION...AJZ MARINE...ALB HYDROLOGY...