Baltimore Harbor & Patapsco River Marine Forecast
| This Afternoon...Ne Winds 5 To 10 Kt. Waves 1 Ft. |
| Tonight...Ne Winds 5 To 10 Kt With Gusts To 20 Kt. Waves 1 Ft. |
| Wed...Ne Winds 10 Kt With Gusts To 20 Kt. Waves 1 Ft. |
| Wed Night...Ne Winds 5 To 10 Kt. Waves 1 Ft. |
| Thu...Ne Winds 5 To 10 Kt. Waves 1 Ft. |
| Thu Night...Se Winds Around 5 Kt. Waves 1 Ft Or Less. |
| Fri...S Winds Around 5 Kt. Waves Flat. |
| Sat...Sw Winds Around 5 Kt. Waves 1 Ft Or Less. |
| Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 200pm EDT Tuesday September 30 2025 Synopsis Canadian high pressure builds south from Ontario and Quebec through the week. A strong cold front will track across the area tonight bringing cooler and drier weather for the middle and latter part of this week. Moderating trend in temps this weekend. Near Term - Through Tonight Lingering showers across central VA will continue through the afternoon. A gradual downward trend should continue in coverage as low-level dry air is advected in on strengthening NNE winds. Otherwise, a thick mid to high level overcast will persist today with gradual thinning this evening, then clearing overnight. A backdoor cold front will then cross the area tonight bringing a cooler and more seasonable air mass for the middle and latter part of the week. This will also bring a much drier airmass into the area. Winds overnight behind the front expected to be out of the NNE at 5-10 mph. Short Term - Wednesday Through Thursday Night Given the quiescent pattern, no major changes to the short term. Building 1090+ mb high pressure from Quebec will be the main story for the middle and second half of the week supporting clear skies Wednesday and Wednesday night. NNE to NE winds will start shifting more to the E Thu as high pressure over the Northeast slides offshore. Models show more cloud cover Thu with a stratocu deck developing as onshore winds develop. Temps will cool down Wednesday and Thu with highs around 70 and falling into the 40s west of I-95. Some patchy frost can't be ruled out in the most sheltered valleys west of the Blue Ridge with the favored areas making a run at 32F. Will look to nail down temperature forecast for Wednesday and Thu night in future shifts, but given the low Tds in the 30s, think some areas could truly bottom out. Long Term - Friday Through Monday Continued influence of strong surface high pressure will remain along the eastern seaboard through the weekend, perhaps drifting slowly eastward early next week. Initially rather flat ridging aloft will expand eastward and amplify by early next week as a series of troughs move through the western part of the continent. Dry conditions should prevail, although there are some hints some moisture could start wrapping around the ridge from the south by Monday. Below normal temperatures on Friday will moderate back above normal over the course of the weekend. Given moderating trend in temps, no frost/freeze concerns overnight. Marine N to NNE winds will strengthen today into Wednesday with SCA (Small Craft Advisory) conditions expected as the pressure gradient tightens with the high to the north and low offshore. Winds will begin to gradually diminish later Wed, but SCA (Small Craft Advisory) conditions may persist into Thu evening. Winds will become southerly Fri, but should remain below advisory criteria into Sat as high pressure remains centered nearby. Tides / Coastal Flooding North to northeast winds are forecast to strengthen today into Wednesday as strong high pressure builds in from the north. This is going to keep tidal anomalies in check. The threat for widespread minor coastal flooding, and possible moderate coastal flooding at Annapolis could occur during the late part of the week. Have issued a Coastal Flood Watch to account for this during the Wednesday night high tide. This will be due to a snapback tide when the strong northeast winds start to diminish Wednesday night, then turn east to southeast Thursday afternoon into Friday. NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories DC...None. MD...Small Craft Advisory from 8pm this evening to 6pm EDT Wednesday for MDZ008. Coastal Flood Watch from Wednesday evening through Thursday morning for MDZ014. VA...None. WV...None. Marine Small Craft Advisory from 8pm this evening to 6pm EDT Wednesday for ANZ530>533-538>542. Small Craft Advisory until midnight EDT Wednesday night for ANZ534-537-543. Small Craft Advisory from 4am to 6pm EDT Wednesday for ANZ535-536. |
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