Baltimore Harbor & Patapsco River Marine Forecast
| Rest Of Tonight...S Winds 5 To 10 Kt. Waves 1 Ft Or Less. |
| Tue...Sw Winds 5 To 10 Kt. Waves 1 Ft Or Less. |
| Tue Night...Sw Winds 5 To 10 Kt. Waves 1 Ft. |
| Wed...Sw Winds 5 To 10 Kt. Waves 1 Ft. Showers With A Chance Of Tstms. |
| Wed Night...N Winds 5 To 10 Kt. Waves 1 Ft. Showers. |
| Thu...Ne Winds 5 To 10 Kt. Waves 1 Ft. Showers Likely. |
| Thu Night...E Winds Around 5 Kt. Waves Flat. A Chance Of Showers. |
| Fri...E Winds 5 To 10 Kt. Waves 1 Ft. Showers. |
| Sat...E Winds 5 To 10 Kt. Waves 1 Ft. Showers. Winds And Waves Higher And Visibilities Lower In And Near Tstms. |
| Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 913pm EDT Monday May 18 2026 .WHAT HAS CHANGED... Minor adjustments to the thunderstorm chances this afternoon and evening based on current radar trends, otherwise no major changes were made to the forecast package. .KEY MESSAGES... 1) Near record warmth continues Tuesday. 2) A strong cold front brings widespread rain and thunderstorm chances on Wednesday, followed by much cooler and showery conditions toward the end of the week. KEY MESSAGE 1... Near record warmth continues Tuesday. Convection from earlier this evening in the Alleghenies have now dissipated, with dry conditions tonight. Patchy fog is possible late tonight. Very mild conditions tonight as lows settle in the upper 60s and low 70s. Even hotter conditions can be expected Tuesday with highs well into the low to mid 90s. A few upper 90s cannot be ruled out across the urban corridor and down to the south across the central VA Piedmont given the strengthened ridge peaking overhead and dry air at the surface. An isolated shower or t-storm remains possible over the mountains, although most will see nothing given the heightened ridge squashing anything overhead. Temperatures cool slightly Wednesday with increasing cloud cover as a cold front approaches the region. Highs will still push into the 90s along with increasing humidity. Even with that said, the combination of heat and humidity will remain below heat headline criteria through the period. KEY MESSAGE 2...A strong cold front brings widespread rain and thunderstorm chances on Wednesday, followed by much cooler and showery conditions toward the end of the week. A strong area of low pressure moves through the Northeast on Wednesday, with a cold front extending down the East Coast that will bring widespread rain and thunderstorm chances to the Mid-Atlantic in the afternoon/evening. While the center low will be well north of us, the timing of the front aligning with the diurnal cycle and the high temperatures seen at the start of the week could still contribute towards some thunderstorm development in the region. Potential severity at this time still ranges widely--NCAR's AI NWP (Numerical Weather Prediction) Convective Hazards Forecast currently has our region outlined in its 45%-60% probability for severe weather to occur, while CSU's medium- range probabilities ranks the severe threat much lower. Regardless, this front will likely result in widespread showers at a minimum as well as a sharp drop in temperatures seen later in the week. Highs on Thursday will range in the upper 60s and low 70s, a marked shift from the mid-90s expected earlier in the week. Lingering rain showers may still be moving out of the area by Thursday morning, while a meandering front to the south could bring a few additional rain showers on Friday. Temperatures begin to increase again going into the weekend, as a warm front meanders through the region Saturday. Upper-level zonal flow slow transitions to UL ridging by the end of the weekend, indicating a potential decrease in rain chances going into the start of next week. Marine SCA (Small Craft Advisory) southerly channeling over the bay and lower tidal Potomac is expected to diminish late this evening. Additional SCAs (Small Craft Advisories) are needed due to channeling Tuesday afternoon and evening. Winds will remain out of the south and southwest with gusts up to 20 kts today and Tuesday. Winds may near low-end SCA (Small Craft Advisory) 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. Small Craft Advisories are likely during the day Thursday & Friday as winds gust up to 15-20 knots, growing calmer overnight. Winds drop below SCA (Small Craft Advisory) thresholds Friday night. Northerly winds shift easterly by Friday morning. 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) NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories DC...None. MD...None. VA...None. WV...None. Marine Small Craft Advisory until 2am EDT Tuesday for ANZ531>534- 537>543. |
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