Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
997 FXUS61 KLWX 161428 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1028 AM EDT Sun Jun 16 2024 .SYNOPSIS... High pressure over New England will drift offshore through the week. A warm front over the Tennessee River Valley will lift northeastward across the Mid-Atlantic through Monday, marking the beginning of a prolonged period of heat. && .NEAR TERM /THROUGH TONIGHT/... MORNING UPDATE: Temperatures are currently on track thus far, with dew points running a few degrees warmer than expected. May touch up the dew point forecast this afternoon if anything, but otherwise, the previous discussion holds true at this time. PREVIOUS DISCUSSION: The high, currently centered over New England, will drift offshore through tonight as a warm front lifts through. This will lead to south-southeasterly return flow and an increase in temperatures and humidity. Highs should be well into the 80s to around 90 for much of the area this afternoon, with warmer lows tonight compared to last night. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Ridging will build over the region aloft early this week as high pressure at the surface continues to drift offshore. The warm front will lift away from the region Monday. Given the increase in heat and humidity, and prior to the ridge aloft and associated subsidence increasing heading into midweek, there may be enough of a window for scattered showers and thunderstorms west of the Blue Ridge Mountains thanks to a develop lee surface pressure trough. Flow will be modest in the mid and upper levels and light in the low levels, so heavy downpours and localized gusty winds would be the main threats with any stronger storms. Given the increase in heat and humidity and slow/chaotic storm motions in the vicinity of the terrain, some isolated heavy rain totals can`t be ruled out. Depending on mesoscale evolution, some cells could drift into the central Shenandoah Valley toward evening. Otherwise, most of the time/area will be dry. Increasing subsidence under the building ridge Tuesday should limit and shower and thunderstorm chances to eastern WV/western MD away from the center of the building ridge. Temperatures will trend hotter each day, with lower 90s likely Monday and middle 90s Tuesday. Muggy nighttime temperatures in the mid 60s to lower 70s are expected. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A highly anomalous upper level ridge will remain in place along the East Coast on Wednesday and Thursday. Most guidance shows this ridge peaking out at around 600 decameters off to our north and east on Thursday. This ridge will flatten out later in the week, with the highest heights dropping to our south by next weekend. High pressure offshore at the surface will lead to continued south to southeasterly flow. As a result, a hot airmass will remain in place through the long term period. High temperatures are forecast to reach into the mid 90s for most on both Wednesday and Thursday, with overnight lows generally in the mid-upper 60s (lower 70s in the urban centers). The hottest conditions are expected from Friday into next weekend. Current forecasts call for highs in the upper 90s, with lower 100s a possibility. Overnight low temperatures will turn warmer as well, with lower 70s for most (mid-upper 70s in the urban centers). While it will be a bit humid, dewpoints will be lower than is typical of many heatwaves (mid-upper 60s in this event, vs low- mid 70s in some other events). This will keep heat index values relatively close to the air temperature (maybe a degree or two higher). Nonetheless, it will be a prolonged period of hot conditions this coming week, and those impacted by the heat should start taking precautions in advance. Conditions are forecast to remain dry on Wednesday through Friday, with mostly sunny skies each day. Low end chances for a popup afternoon or evening thunderstorm will return by Saturday and Sunday. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... VFR conditions are forecast at the TAF sites through Tuesday night. The main story will be increasing temperatures. South to southeast flow is expected during this time, 5 knots or less at night and 7-11 knots during the day with occasional gusts to around 15 knots in the mid/late afternoon. Scattered convection may develop west of the TAF sites near the Appalachians Monday. VFR conditions and southerly winds are expected at the terminals on both Wednesday and Thursday. && .MARINE... Southerly to southeasterly flow is expected through the next few days, with channeling and bay/river breeze enhancement leading to 20-25 kt gusts over at least portions of the area waterways each afternoon and evening. Winds may approach low-end SCA levels in channeled southerly flow both Wednesday and Thursday afternoon/evening. && .TIDES/COASTAL FLOODING... Tide levels will increase amid south/southeasterly flow through mid week. Near minor flooding is possible particularly near Annapolis late tonight into Monday morning, and late Monday night into Tuesday morning. && .CLIMATE... Hot temperatures are expected next week. Below is a list of record high temperatures for June 17th through 22nd, the year the record was set, and the current forecast high temperatures for those days. RERs are currently only issued for DCA, IAD, BWI, and MRB, but other sites are shown for reference. Monday Jun 17th Climate Site Record High Forecast High Washington-National (DCA) 99F (2022) 93F Washington-Dulles (IAD) 96F (2022) 93F Baltimore (BWI) 96F (2022+) 92F Martinsburg (MRB) 98F (1939+) 92F Charlottesville (CHO) 97F (2022) 93F Annapolis (NAK) 96F (1939) 88F Hagerstown (HGR) 96F (1952) 93F Tuesday Jun 18th Climate Site Record High Forecast High Washington-National (DCA) 97F (1944) 95F Washington-Dulles (IAD) 94F (2018+) 95F Baltimore (BWI) 97F (1957+) 94F Martinsburg (MRB) 99F (1943) 94F Charlottesville (CHO) 96F (2014+) 96F Annapolis (NAK) 96F (1957) 89F Hagerstown (HGR) 95F (1957) 95F Wednesday Jun 19th Climate Site Record High Forecast High Washington-National (DCA) 99F (1994) 93F Washington-Dulles (IAD) 98F (1994) 95F Baltimore (BWI) 99F (1994) 93F Martinsburg (MRB) 96F (1994+) 94F Charlottesville (CHO) 97F (2018) 96F Annapolis (NAK) 96F (1993) 89F Hagerstown (HGR) 97F (1994) 96F Thursday Jun 20th Climate Site Record High Forecast High Washington-National (DCA) 99F (1931) 95F Washington-Dulles (IAD) 97F (1964) 96F Baltimore (BWI) 100F (1931) 95F Martinsburg (MRB) 98F (1931) 96F Charlottesville (CHO) 98F (1933) 97F Annapolis (NAK) 98F (1988) 90F Hagerstown (HGR) 98F (1931) 96F Friday Jun 21st Climate Site Record High Forecast High Washington-National (DCA) 99F (2012) 98F Washington-Dulles (IAD) 98F (1988) 98F Baltimore (BWI) 100F (2012+) 97F Martinsburg (MRB) 102F (1931) 97F Charlottesville (CHO) 99F (1933) 99F Annapolis (NAK) 100F (1988) 92F Hagerstown (HGR) 97F (1923) 97F Saturday Jun 22nd Climate Site Record High Forecast High Washington-National (DCA) 101F (1988) 99F Washington-Dulles (IAD) 99F (1988) 99F Baltimore (BWI) 100F (1988) 99F Martinsburg (MRB) 102F (1933) 98F Charlottesville (CHO) 101F (1933) 99F Annapolis (NAK) 101F (1988) 94F Hagerstown (HGR) 100F (1988) 98F + indicates that value has been reached on multiple years, with the year displayed being the most recent. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 2 PM this afternoon to 2 AM EDT Monday for ANZ531>534-537-540-541-543. Small Craft Advisory from 2 PM Monday to 2 AM EDT Tuesday for ANZ531>534-537-540-541-543. && $$ SYNOPSIS...DHOF NEAR TERM...DHOF/CJL SHORT TERM...DHOF LONG TERM...KJP AVIATION...DHOF/KJP MARINE...DHOF/KJP TIDES/COASTAL FLOODING... CLIMATE...