Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
306 FXUS61 KLWX 240800 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 400 AM EDT Mon Jun 24 2024 .SYNOPSIS... A cold front will pass through the area early this morning. High pressure will briefly traverse the area Tuesday. The next cold front will cross the area late Wednesday into Thursday. High pressure will pass to the north Friday, then another frontal system will approach over the weekend. && .NEAR TERM /THROUGH TONIGHT/... A cold front is pushing through the area early this morning. Scattered showers are crossing the area but most have been dissipating as greater surface inhibition is being encountered. Guidance does indicate some renewal of convection chances, especially southeast of I-95, as the front encounters greater instability across southern Maryland. Any such activity would likely push to the south by noon, if not sooner. Locations along the Alleghenies may also see a few more showers through the morning hours as the upper level trough approaches. Northwesterly winds will increase from mid morning into the afternoon, with gusts of 20-30 mph expected. Remaining clouds will clear, with few to scattered cumulus. High temperatures will return closer to normal in the mid 80s to near 90. However, humidity levels will plummet, with dew points in the mid 50s by late afternoon. That dry airmass will lead to a relatively cool night as high pressure builds in from the west and winds abate. The urban centers and bayshore may stay close to 70, but interior locations will drop to the mid 50s to mid 60s. Some of the high elevation valleys could fall into the 40s. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... The surface high will translate through on Tuesday and move to the southeast Tuesday night. Comfortable dew points in the mid to upper 50s remain through the day, although temperatures will rebound a little to the upper 80s and lower 90s. A light southerly flow and potential clouds will result in warmer conditions Tuesday night. Dry conditions are most likely, although some guidance shows the potential for a few showers and thunderstorms Tuesday night across northwestern parts of the CWA on the leading edge of theta-e advection. With the low level ridge to the southeast Wednesday, southwesterly flow will advect heat and humidity back into the area. A series of troughs and a cold front will also be approaching from the northwest. Early day clouds and even remnant showers are not out of the question, which could inhibit temperatures somewhat. However, the potential is still there for highs in the mid to upper 90s and heat index values around 100-105. With the building instability and approaching forcing, a thunderstorm threat will eventually develop, although details are still fuzzy at this range. Current timing favors a later afternoon to evening peak. Increased flow with the incoming trough will support a risk for strong to severe thunderstorms. The cold front looks like it will push through late Wednesday night, which would diminish rain chances. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As a cold front exits early Thursday, some shower activity could linger into Thursday morning. Temperatures lower behind the cold front Thursday into the 80s to low 90s, but dewpoints look to remain in the low-mid 60s during the day, dropping into the 50s overnight with lows temps in the 50s to near 70 along the waters. A quick-moving area of high pressure passes to our north on Friday. Mostly dry conditions are expected, but a few showers can`t be ruled out around the Shenandoah Valley/Virginia Piedmont as the center of high pressure swiftly moves offshore by the evening and minor perturbations pass by aloft. Temperatures look relatively cooler, topping out in the upper 80s. Lows hover in the 60s. Confidence has increased for the potential of warm frontal precip on Saturday, focused in the afternoon and evening. The cold front associated with the approaching system looks to arrive Sunday. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... A cold front is pushing across the area this morning. It appears that any additional showers that develop along the front should be southeast of the TAF sites. Winds are shifting to the west, and then will become northwesterly after sunrise with increasing gusts. Gusts of 20-30 kt will be likely through the afternoon before abating this evening. No significant weather expected tonight through Tuesday night as high pressure moves across the area. Thunderstorm chances increase Wednesday into Wednesday evening, perhaps in multiple rounds, as the next system approaches the area. Southwesterly winds may also gust to 20 kt Wednesday. Prevailing VFR conditions are expected Thursday and Friday. Mostly dry conditions are expected as high pressure passes to the north, but a few showers/t-storms can`t be ruled out Thursday AM and Friday PM. NW flow Thursday turns SW on Friday. && .MARINE... Southwesterly winds remain gusty early this morning, especially on the middle bay with gusts to 25 kt. A cold front will pass through this morning with a wind shift to the west then northwest. A thunderstorm can`t be ruled out near southern Maryland this morning as the front passes. A Small Craft Advisory is in effect for all waters today. Gusts of 20-25 kt are likely, with a few gusts to 30 kt not out of the question. Winds gradually subside Monday night, with advisories continuing along the bay until 2 AM. High pressure builds across the area Tuesday, with light west winds becoming southerly by Tuesday night. An SCA may be needed for the bay Tuesday night due to southerly channeling. SCA conditions may expand to all waters Wednesday into Wednesday evening as southwesterly flow increases. There will also be an increasing threat of strong thunderstorms Wednesday afternoon and evening as the next frontal system approaches. Sub-SCA conditions are expected Thursday and Friday as high pressure passes to our north. A frontal system arrives over the weekend. && .TIDES/COASTAL FLOODING... Tidal anomalies decrease today through Tuesday with NW flow. A few sensitive sites may approach or exceed Action stage today, but no flooding is expected at this time. A return of southwest winds Wednesday will bring another increase in water levels, although no flooding is forecast at this time. && .CLIMATE... Very hot temperatures are expected on Wednesday. Several records could be in jeopardy, as seen below. Below is a list of record high temperatures for Jun 26th, the year the record was set, and the current forecast high temperatures for that day. A plus sign after the date signifies the record was set multiple times, with the most recent year indicated below. RERs are only issued for DCA, IAD, BWI, and MRB, but other sites are shown for reference. Wednesday Jun 26th Washington-National (DCA) 101F (1952) 97F Washington-Dulles (IAD) 95F (1998) 96F Baltimore (BWI) 99F (1954+) 97F Martinsburg (MRB) 102F (1943) 94F Charlottesville (CHO) 99F (1998) 96F Annapolis (NAK) 98F (1952) 92F Hagerstown (HGR) 98F (1954+) 93F && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ530>534- 537>541-543. Small Craft Advisory until 8 PM EDT this evening for ANZ535- 536. Small Craft Advisory until 8 PM EDT this evening for ANZ542. && $$ SYNOPSIS...ADS NEAR TERM...ADS SHORT TERM...ADS LONG TERM...CAS AVIATION...ADS/CAS MARINE...ADS/CAS TIDES/COASTAL FLOODING...CAS CLIMATE...LWX