Baltimore Harbor & Patapsco River Marine Forecast
| This Afternoon...Ne Winds 5 To 10 Kt. Waves 1 Ft. |
| Tonight...E Winds 5 To 10 Kt. Waves 1 Ft. |
| Sun...E Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Rain. |
| Sun Night...E Winds 5 To 10 Kt. Waves 1 Ft. Rain. |
| Mon...E Winds 5 Kt. Waves Flat. Rain Likely. |
| Mon Night...S Winds 5 To 10 Kt With Gusts To 20 Kt. Waves 1 Ft. Rain. |
| Tue...W Winds 5 To 10 Kt...Becoming N After Midnight. Waves 1 Ft Or Less. |
| Wed...Se Winds Around 5 Kt...Becoming Sw. Waves 1 Ft Or Less. A Chance Of Rain In The Afternoon. Rain Likely Through The Night. |
|
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 929am EST Sat Dec 14 2024 Synopsis High pressure will remain near New England through Sunday as weak low pressure moves toward the Great Lakes. As a second, stronger area of low pressure moves north of the Great Lakes Monday, the trailing cold front will cross the area early Tuesday. After brief high pressure, another low pressure system may affect the area late Wednesday into Thursday. Near Term - Through Tonight MID-MORNING Patches of low-level clouds remain over NE MD and central VA this morning while high clouds gradually stream in from the west. The low deck is expected to fizzle out through the morning, allowing for some sun early in the afternoon in these locations before denser cloud cover builds in this later in the day. Below normal temperatures are expected today with highs in the low 40s (low 30s in the mountains) as cold air damming continues with strong high pressure to our north. A surface low over the Plains is expected to occlude as it progresses east tonight. At the same time, an upper shortwave will be moving into the Great Lakes/Ohio Valley. These features will be our next weather-makers, but precipitation is expected to hold off until early Sunday morning. Low temperatures fall into the 20s for most of the area, and low 30s in the metros and along the waters. PREVIOUSLLOWS... Strong high pressure (1045+ mb) extends from Canada toward the Mid Atlantic downstream of an upper ridge. As the high becomes centered near New England later today, a classic cold air damming pressure pattern will begin to develop east of the Appalachians. Through tonight, however, conditions should remain dry (except for a low chance of snowflakes toward dawn in the far southwestern CWA). There's some uncertainty with what happens with the two lower level cloud decks (N MD and central VA), although it does appear there should be an opportunity for some sun before mid and high level clouds start increasing later this afternoon. Clouds will thicken further as the night progresses. Below normal temperatures continue with highs in the mid 30s to lower 40s today. Most locations other than the urban cores and bayshore should drop into the mid to upper 20s again tonight. Short Term - Sunday Through Monday Night The next weather system doesn't have a notable surface reflection, rather being driven by a shortwave aloft and moist/warm advection over top of the cold air damming wedge. Light precipitation will spread into areas mainly west of the Blue Ridge during the morning (thus presenting the highest wintry weather potential), gradually spreading east during the afternoon and evening. Uncertainty abounds with multiple aspects of this system from onset time, to thermal profiles, to precipitation rates/amounts...essentially the ingredients that go into snow/ice amount forecasting. A subset of guidance holds onto deep cold air longer despite increasing warm advection aloft, which could allow for several (if not nearing locally 6) inches of snow for portions of the Potomac Highlands. What seems more plausible is a period of snow and sleet on the front end with a change over to freezing rain. Due to the strength of the high replenishing cold surface air, locations along the eastern slopes of the Allegheny Front could see around a quarter inch of ice. The Winter Storm Watch has been expanded by a couple zones to account for this potential. Most of the more notable snow and ice accumulations should be confined to the ridges, but almost anywhere west of the Blue Ridge could see a little accumulation. While some brief snow/sleet could occur at onset northwest of I-95, it does seem like the later onset east of the Blue Ridge should preclude any accumulations (temperatures should warm into the upper 30s if not 40s). Wintry precipitation should gradually change over to rain, with the larger rain shield pushing east Sunday night. Our typical northwestern cold pocket could hang on to some light freezing rain/drizzle since the surface pressure pattern will not be conducive for scouring out any lingering surface cold air. Remaining rain moves east of the Chesapeake Monday morning as the trough departs and a shortwave ridge moves overhead. The surface high will begin to move east of New England, but the pressure gradient will remain weak, and clouds will likely remain in place. While guidance has temperatures warming into the upper 40s to mid 50s, I have some doubts due to the remnant CAD airmass, especially in the northwestern areas where wintry accumulations may persist and cold air is tougher to scour out of the Potomac Valley. While the next area of low pressure will move north of the Great Lakes, the associated shortwave and trailing cold front will approach the area Monday night. Precipitation associated with this system should only be rain as southerly flow strengthens and the atmosphere warms further. Some of the highest ridges could have wind gusts above 40 mph as the stronger wind fields aloft affect the area. There is some uncertainty with how far south rain makes it through the forecast area given the displaced forcing, although everywhere stands the chance for at least a few light showers. Long Term - Tuesday Through Friday Quasi-zonal flow builds in briefly Tuesday/Tuesday nigh ahead of a surface cold front that moves through the region Tuesday morning. Surface high pressure builds in ahead of the next shortwave trough that will bring precipitation to the area later Wednesday into Thursday. At this time, rain looks to be favored for most of the CWA. NW flow aloft and a few embedded disturbances bring the potential for upslope snow showers Thursday into Friday. An Alberta Clipper type system looks to move near the Great Lakes Friday and eastward Saturday. At this time cannot rule out some precipitation (rain or snow) across the area, but better forcing is to the north. Temperature wise, Tuesday will be the warmest day of the week with 60s where the sun breaks out (currently DC metro south into central VA). Temps Tuesday will be stuck in the 40s across the mountains. Cooler Wednesday with 40s and 50s. As the front moves through Thursday, that is when temperatures start to plummet. Highs Thursday in the upper 20s to 30s in the mtns with 40s elsewhere. Much of the same Friday, though about 5 degrees cooler than Thursday. Saturday will be the coldest day of the long term with highs not getting out of the 30s (teens/20s mtns). Single digit to teens wind chills possible Friday and Saturday night. Marine Northeasterly winds are slightly enhanced along the wider waters of the bay this morning. A Small Craft Advisory is in effect for the mid bay until 10 AM. Another period of stronger winds could affect this same area this evening, but confidence is not high enough for another advisory. Winds will remain below advisory criteria later tonight through Monday as high pressure remains to the northeast and a weak weather system crosses the area with some rain Sunday night. Southerly flow will increase Monday night ahead of the next frontal system, with advisories likely needed during this time. SCA (Small Craft Advisory) winds likely behind the front Tuesday. Diminishing Tuesday evening. No marine wind hazards expected Wednesday. NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories DC...None. MD...Winter Storm Watch from Sunday morning through Monday morning for MDZ001-501. VA...None. WV...Winter Storm Watch from Sunday morning through Monday morning for WVZ501-503-505. Marine Small Craft Advisory until 10am EST this morning for ANZ534- 543. |
Baltimore/Washington Radar
Northeast Radar
East Coast Satellite