Marine Weather and Tide Forecast for Baltimore Highlands, MD

KEY MESSAGES
- 1) Feeling more like Summer with near record breaking temps and daily shower and thunderstorm chances through Tuesday.

- 2) A strong cold front moves through on Wednesday, bringing chances for thunderstorms. Much cooler and showery conditions are expected to end the week.

DISCUSSION
KEY MESSAGE 1... Feeling more like Summer with near record breaking temps and daily shower and thunderstorm chances through Tuesday.

Still tracking some shower activity along the leading edge of a decaying MCV moving across the region as of 10 AM this morning.
Shower activity, and thus cloudcover, was higher than originally anticipated, so bumped that up with the morning forecast package. Also, bumped up the POPs this afternoon into the "scattered" category. Could still see this going either way, but latest hi-res guidance all has at least some minimal convective development after 1-2 PM, so wanted to bump things up a bit.

PREVIOUS DISCUSSION: The remnant MCV feature will cross the region late morning into midday leading to additional spotty shower and t-storm chances, especially in areas along and north of I-66/US-50. 00z CAMS remain all over the place when it comes to coverage and timing given the strengthening high offshore and morning convective debris which could dampen additional shower/thunderstorm development. With zonal flow in place any additional waves of energy ejecting from west to east out of the Ohio/MS River Valley could touch off a shower or t-storm given the increased heat and humidity. Once again confidence is low given west to northwest downsloping flow east of the mountains which would make for a more hit or miss type of environment. Any storms that we do see today could put down locally gusty winds, brief heavy rainfall, and frequent lightning. Expect a similar setup Monday and Tuesday although the coverage of storms will be further reduced as upper level ridging continues to strengthen east of the region. Showers and t-storms will be confined to the mountains due to terrain influences and a lack of lifting mechanism.

Outside of the afternoon/evening shower and thunderstorm threat will be the bigger story which is the heat. Did cut back highs a little bit today due to added mid and high level cloud cover. Most locations will push into the mid to upper 80s with upper 70s over the mountainS. Locations south and east of DC/Baltimore could push toward 90 degrees with more sunshine. The bigger heat builds into the area Monday and Tuesday with widespread highs in the low to mid 90s. Tuesday will mark the hottest day of the next 7 with highs in the mid to upper 90s east of the mountains. Humidity will gradually increase as well although not to the extent where heat headlines will be needed. Something that we'll continue to monitor since we are early in the season. Don't expect too much relief from the heat at night with low temperatures Monday and Tuesday nights in the mid 60s and low 70s.

KEY MESSAGE 2...A strong cold front moves through on Wednesday, bringing chances for thunderstorms. Much cooler and showery conditions are expected to end the week.

The strong upper ridge overhead will finally break down on Wednesday as a large trough tracks eastward across Ontario and Quebec. A strong cold front associated with this system will track southeastward across the Great Lakes and Ohio Valley over the course of the day. Heat and humidity will remain in place in advance of the front, with dewpoints holding in the 60s and temperatures forecast to climb into the mid 90s at lower elevations once again. Showers and thunderstorms are expected to form across the area in advance of the front Wednesday afternoon. The strongest winds at mid to upper levels look like they will pass to our north, so shear won't be overly impressive. However, a few stronger storms can't be ruled out with ample instability in place.

The front will push through our area Wednesday night as strong high pressure builds to our north over the Great Lakes. Northerly winds will advect a much cooler airmass into the region for Thursday, with temperatures only forecast to make it into the lower 70s. The high will then shift off to our northeast for Friday and Saturday, causing winds to turn out of the east. Meanwhile, weak troughing at mid-upper levels is expected to become established across the Mississippi and Tennessee Valleys, placing us in southwesterly flow aloft. This will result in a pattern where warm advection ensues aloft atop the onshore flow. Cloudy and showery conditions will be the result for Thursday, and especially for Friday and Saturday.
While the pattern doesn't look overly favorable for thunderstorms, rain from the frequent showers should add up, with ensemble mean rainfall totals for the Wednesday through Saturday period generally between one and two inches across the entire forecast area. If this solution were to verify, it could provide some much needed drought relief to the region.

AVIATION /13Z SUNDAY THROUGH THURSDAY/
A few spotty light showers/drizzle may impact the terminals this morning, but should not lead to any significant restrictions. CIGs have been keeping around 5 kft, with VSBYs generally not being reduced below 5-6 SM. Can't rule out a thunderstorm later this afternoon, so have PROB30s in the latest TAFs to reflect that threat. Confidence is very low that any storm will hit a terminal, but think there will at least be a few storms out there this afternoon.

Prevailing VFR conditions are expected across the terminals through Tuesday as high pressure strengthens offshore. Light and variable winds this morning will turn westerly this afternoon at less than 10 kts. South/southwesterly winds return Monday and Tuesday gusting between 15 to 20 kts during the afternoon and evening hours. Daily shower and thunderstorm chances will occur each afternoon although coverage will be spotty in nature between the terminals. The highest confidence for showers and t-storms appears to be west of MRB, HGR, and FDK. where brief reductions are possible. Elsewhere confidence remains low given the lack of a lifting mechanism.

Prevailing VFR conditions are expected on Wednesday, but temporary drops to sub-VFR conditions may be possible during thunderstorms.
Restrictions may also be possible at times during showers on Thursday. Winds will be out of the southwest on Wednesday, before turning out of the north on Thursday.

MARINE
Sub-SCA level winds are expected today through Monday, although occasional gusts up to SCA levels are possible in channeling, especially over the open waters during this aforementioned time.
Light and variable winds today will switch to the west this afternoon at less than 10 kts. South southeasterly winds return Monday with gusts up to 20s across the bay and lower tidal Potomac. Additional SCAs may be needed due channeling Tuesday into TUesday night especially over the wider waters. Winds will continue out of the south and southwest with gusts up to 20 kts.

Winds may near low-end SCA levels in south to southwesterly flow on Wednesday, and then again in northerly flow on Thursday. SMWs appear possible Wednesday into Wednesday night as thunderstorms move over the waters.

CLIMATE
Here are some daily temperature records during the May 18-20, 2026 timeframe:

A '+' sign indicates multiple years currently hold that record.
A '!' sign indicates the record is forecast to be tied or broken.

***MONDAY, MAY 18TH, 2026*** LOCATION RECORD HIGH (YEAR) RECORD WARM LOW (YEAR)
Washington-National (DCA) 96F (1877) 72F (2015)
Washington-Dulles (IAD) 91F (1987)! 68F (2015)! Baltimore (BWI) 97F (1962) 70F (2017)
Baltimore Inner Harbor (DMH) 97F (1962) 75F (2017)
Martinsburg (MRB) 96F (1911) 66F (2015)! Charlottesville (CHO) 95F (1962)+ 73F (1911)
Annapolis (NAK) 95F (1962)+ 69F (1953)+! Hagerstown (HGR) 93F (1962) 71F (2017)

***TUESDAY, MAY 19TH, 2026*** LOCATION RECORD HIGH (YEAR) RECORD WARM LOW (YEAR)
Washington-National (DCA) 96F (1997)+ 72F (2015)! Washington-Dulles (IAD) 92F (1997)+! 66F (2017)+! Baltimore (BWI) 98F (1962) 75F (1877)
Baltimore Inner Harbor (DMH) 98F (1962) 78F (1962)
Martinsburg (MRB) 98F (1911) 69F (1996)! Charlottesville (CHO) 97F (1962) 72F (1997)
Annapolis (NAK) 96F (1962) 71F (1911)! Hagerstown (HGR) 97F (1996) 69F (2017)+!

***WEDNESDAY, MAY 20TH, 2026*** LOCATION RECORD HIGH (YEAR) RECORD WARM LOW (YEAR)
Washington-National (DCA) 96F (1996) 73F (2019)
Washington-Dulles (IAD) 93F (1996) 69F (2019)
Baltimore (BWI) 95F (1962) 71F (2019)+ Baltimore Inner Harbor (DMH) 97F (1962) 74F (1998)+ Martinsburg (MRB) 97F (1911) 70F (1998)
Charlottesville (CHO) 96F (1996) 73F (1996)
Annapolis (NAK) 98F (1997) 76F (1898)
Hagerstown (HGR) 97F (1996) 66F (1998)

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.