Area Forecast Discussion
Issued by NWS Sterling, VA
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Issued by NWS Sterling, VA
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-- Discussion containing changed information from previous version are highlighted. --276 FXUS61 KLWX 150048 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 848 PM EDT Fri Jun 14 2024 .SYNOPSIS... A cold front will cross the Mid-Atlantic tonight. High pressure builds in this weekend. A warm front lifts across the region Monday as high pressure shifts off the East Coast through next week. A prolonged period of hot temperatures take hold of the region next week. && .NEAR TERM /THROUGH TONIGHT/...-- Changed Discussion --A few severe thunderstorms managed to develop out over eastern WV earlier this afternoon along an approaching cold front. The remnants of this convection have grown into a much weaker line of showers with a few embedded rumbles of thunder. This is due to a substantial decrease in instability as you move east. Shear is on the increase, but with minimal instability east of I-81 owing to westerly flow in the mid-upper levels, not likely to see any sort of redevelopment of stronger storms this evening. With the cold front sweeping through, these showers will quickly move east during the early portions of the overnight hours, likely clearing east of the area by 2-4 AM. Skies will rapidly clear in its wake, giving way to mostly clear skies by Saturday morning. Low temperatures will be closer to the low 60s.-- End Changed Discussion --&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Large surface high over southern ON/central Great Lakes on Saturday quickly shifts east over the Northeast, then off the southern New England coast Sunday night. Dry and seasonal conditions expected. Afternoon highs reach the low to mid 80s each day, with mid to upper 70s in the mountains. Seasonal overnight lows in the mid 50s to low 60s Saturday night. A warm front lifts north through the area Sunday night, bringing in milder temperatures. && .LONG TERM /MONDAY THROUGH FRIDAY/... Strong upper level ridging will dominate the weather pattern throughout the long term period, with dry conditions and well above normal temperatures expected. At the surface, high pressure builds over the Mid-Atlantic and lingers through the week. There remains uncertainty amongst global guidance with regards to the exact placement of the upper level ridge, with the ECMWF having the driest solution. On the contrary, the GFS and Canadian show increased moisture aloft as the ridge pivots overhead leading to a chance of showers and thunderstorms in the afternoon. For the forecast, PoPs are trending low with primarily dry conditions expected for our area but a stray shower or sprinkle cannot be ruled out in the western portions of the area. The main weather hazard for next week will be above normal temperatures. High temperatures east of the Alleghenies will rise well into the 90s each day with increased humidity leading to warming heat indices and record high temperatures are possible. Heat indices in the upper 90s are expected with lower to mid 100`s possible. As the ridge axis pivots over the area, southerly winds will shift to southeasterly, providing a slight cool down with high temperatures in the mid 90s expected. That being said, relative humidities will increase with southeasterly flow which will possibly lead to continued heat index concerns. Heat advisories or heat watches may be needed at some point during the long term. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...-- Changed Discussion --Made some substantial changes to the TAFs this evening, as showers and storms arrived a few hours later than originally anticipated. Took thunder out of the TAFs, except for MRB, as instability greatly decreases the further east you go. Some potentially moderate showers will move through in the next few hours, but confidence in thunder was just too low to include in TAFs at this time. If we do start to see lightning get close, TAFs will be modified to reflect that threat. Behind the cold front this evening, VFR conditions are expected tonight through the weekend. Northerly winds Saturday weaken Saturday night into Sunday, eventually becoming east to southeast. VFR conditions are expected both Monday and Tuesday with hot and dry conditions expected at all terminals. Winds remain light, blowing 5- 10 knots, out of the south.-- End Changed Discussion --&& .MARINE...-- Changed Discussion --Small Craft Advisories had to be hoisted all along the Chesapeake Bay as much more wind was brought down this evening in the northern portions of the Bay. This surge of northerly flow will make its way down the Bay this evening before a brief lull during portions of the overnight. Northerly channeling then kicks in once again behind the cold front, producing SCA conditions over most of the waters of the Chesapeake Bay and Lower Tidal Potomac. Another Small Craft Advisory is in effect from early Saturday morning through Saturday afternoon. After that, winds diminish below SCA conditions through Sunday night as high pressure shifts offshore of the New England coast. Local winds go from north to east, then southeast Sunday afternoon. Southerly channeling will lead to possible SCA conditions both Monday and Tuesday. Outside of gusty winds, hot and dry conditions are expected to start out the week.-- End Changed Discussion --&& .CLIMATE... High temperatures for next week. Below is a list of record high temperatures for June 17th, 18th, 19th, and the 20th and the year the record was set, and the current forecast high temperatures for those days. Daily temperature records are currently only maintained at DCA, IAD, BWI, and MRB. Others are shown for reference. Monday Jun 17th Climate Site Record High Forecast High Washington-National (DCA) 99F (2022) 95F Washington-Dulles (IAD) 96F (2022) 95F Baltimore (BWI) 96F (2022+) 93F Martinsburg (MRB) 98F (1939+) 93F Charlottesville (CHO) 97F (2022) 94F Annapolis (NAK) 96F (1939) 88F Hagerstown (HGR) 96F (1952) 94F Tuesday Jun 18th Climate Site Record High Forecast High Washington-National (DCA) 97F (1944) 97F Washington-Dulles (IAD) 94F (2018+) 97F Baltimore (BWI) 97F (1957+) 95F Martinsburg (MRB) 99F (1943) 95F Charlottesville (CHO) 96F (2014+) 96F Annapolis (NAK) 96F (1957) 90F Hagerstown (HGR) 95F (1957) 97F Wednesday Jun 19th Climate Site Record High Forecast High Washington-National (DCA) 99F (1994) 94F Washington-Dulles (IAD) 98F (1994) 95F Baltimore (BWI) 99F (1994) 92F Martinsburg (MRB) 96F (1994+) 93F Charlottesville (CHO) 97F (2018) 94F Annapolis (NAK) 96F (1993) 87F Hagerstown (HGR) 97F (1994) 95F Thursday Jun 20th Climate Site Record High Forecast High Washington-National (DCA) 99F (1931) 94F Washington-Dulles (IAD) 97F (1964) 95F Baltimore (BWI) 100F (1931) 92F Martinsburg (MRB) 98F (1931) 93F Charlottesville (CHO) 98F (1933) 93F Annapolis (NAK) 98F (1988) 88F Hagerstown (HGR) 98F (1931) 94F + indicates that value has been reached on multiple years, with the year displayed being the most recent. && .LWX WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ530>534- 537>543. Small Craft Advisory from 4 AM to 11 AM EDT Saturday for ANZ530>532-538>541. Small Craft Advisory from 4 AM to 3 PM EDT Saturday for ANZ533- 534-537-542-543.-- End Changed Discussion --&& $$ SYNOPSIS...DHOF NEAR TERM...CJL SHORT TERM...KRR LONG TERM...AVS AVIATION...AVS/CJL/KRR MARINE...AVS/CJL/KRR CLIMATE...LWX