


Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
328 FXUS61 KLWX 150140 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 940 PM EDT Mon Jul 14 2025 .SYNOPSIS... A cold front will approach from the northwest over the next couple of days before stalling nearby by mid-week. This boundary returns northward as a warm front on Wednesday. Another cold front moves through the region late Friday before settling in the vicinity during the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Heavy showers and thunderstorms continue pushing through southern Maryland this evening, and should be out of the area east of the Chesapeake Bay by 11 PM. Some lingering light rain on the backside of earlier storms continues along/east of US-15 through around midnight. Elsewhere, convection has mostly dissipated with mostly dry conditions across the area tonight. Flood warnings continue for parts of the DC and Baltimore metro areas due to lingering high water that is closing several roadways. Do not drive through flooded roadways, find an alternate route to your destination. A mild/humid night ahead with low temperatures in the upper 60s to mid 70s (low/mid 60s for the mountains). Calm winds and saturated low- levels will enhance the potential for overnight patchy fog, some becoming locally dense in nature. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... While a couple of days ago this frontal system was expected to cross through tonight, that will certainly not be happening. The current model guidance and forecast products support this boundary nearing the Mason-Dixon Line by Tuesday afternoon. However, until all of today`s convection clears the area tonight, it remains to be seen where this boundary truly settles. Unless this system completely clears the region, a seasonably warm and humid air mass should be in play for Tuesday. The larger difference between the two days is more limited upper forcing/support. Subtle height rises are expected along with less identifiable mesoscale perturbations. While shower/thunderstorm chances are still in the 50 to 70 percent range, these should be more instability driven and be more pulse-like in nature. Cell motions may be on the slower side again, which coupled with previous days of heavy rainfall, will maintain a non-zero flash flood threat over the area. A Slight Risk for excessive rainfall has been maintained over pretty much all locations outside of Garrett and St. Mary`s counties. Outside of another round of potentially active weather, Tuesday`s highs are forecast to rise into the mid/upper 80s, with heat indices into the mid 90s. For the overnight, very little change is expected from previous nights with another round of patchy fog possible. The boundary which lingers nearby into Wednesday is expected to lift northward as a warm front. A number of models show a slew of convective perturbations in the quasi-zonal flow. These should be an impetus to a more active convective day. However, given these are tied to storm-scale processes, there is plenty of uncertainty at this juncture. The chances for showers and thunderstorms rise to 60 to 80 percent. Forecast high temperatures push into the upper 80s to low 90s, which is accompanied by heat indices approaching the century mark. Being deeper into the tropical air mass, conditions will be milder overnight with lows in the low/mid 70s (closer to the upper 70s inside D.C. and Baltimore). && .LONG TERM /THURSDAY THROUGH MONDAY/... A fairly persistent pattern is expected on the synoptic scale throughout the long term period. Flow aloft will generally be out of the west across northern portions of the CONUS/southern Canada through the period, with various weak disturbance embedded within zonal flow passing by to our north. We`ll remain within a very warm and humid airmass through at least Friday. Thereafter, there`s some uncertainty regarding whether or not we will get a true cold frontal passage that will drop temperatures and dewpoints. Daily showers and thunderstorms are expected during the afternoon/evening hours as various disturbances pass off to our north. Temperatures will run near to slightly above normal with highs in the upper 80s to mid 90s, and lows in the upper 60s to mid 70s. Thunderstorms may be capable of producing isolated instances of flash flooding or damaging winds any of these days. The day that currently stands out the most from a synoptic standpoint will be Friday, when a cold front will approach the area from the north and west. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... VFR conditions have returned to all terminals this evening. Will watch for patchy fog possible at nearly all TAF sites tonight. IFR conditions are being forecast at KCHO. The following couple of days also present a risk of convection, particularly on Wednesday afternoon/evening. It does appear the frontal system will not clear the region and actually retreat northward as a warm front on Wednesday. Until the region gets out of this pattern, daily convective chances will support a potential for afternoon/evening restrictions. Prevailing VFR conditions are expected on both Thursday and Friday. Winds will be out of the southwest on Thursday, and then west on Friday. && .MARINE... Strong thunderstorms continue moving across southern Maryland and the adjacent local waters through late this evening, then dry conditions overnight. Generally light winds continue through tonight. Tuesday and Wednesday also carry a risk of convection, with the latter likely being the more active of the two days. Thus, hazardous boating conditions are possible at times, particularly during the afternoon/evening periods. As a warm front lifts northward on Wednesday, an uptick in southerly winds are expected, particularly for the evening to overnight hours. Small Craft Advisories may be needed for the southern most waters as gusts push to near 20 knots. Sub-SCA level winds are expected over the waters on both Thursday and Friday. Winds will generally be out of the southwest on Thursday and west on Friday. SMWs may potentially be needed as a result of thunderstorms either afternoon or evening. && .TIDES/COASTAL FLOODING... A prolonged period of southeasterly winds will lead to elevated tidal anomalies through midweek. This carries most of the tidal locations into Action stage, particularly during the higher of the two astronomical high tide cycles. Sensitive locations, such as Annapolis, are forecast to stay just below Minor stage during the high tide cycles this morning. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Flood Watch until midnight EDT tonight for MDZ017-018. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BRO NEAR TERM...KRR/BRO SHORT TERM...BRO LONG TERM...KJP AVIATION...KRR/BRO/KJP MARINE...KRR/BRO/KJP TIDES/COASTAL FLOODING...LWX