718 FXUS61 KLWX 121409 AFDLWXArea Forecast Discussion National Weather Service Baltimore MD/Washington DC 1009 AM EDT Sun Oct 12 2025
.SYNOPSIS... A coastal low near the Carolina coast will move north along the Mid- Atlantic coast through the start of the week. The low, along with upper energy from the west, will move out to sea Tuesday into Wednesday. An area of high pressure will build into the region toward the middle of the week.
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.NEAR TERM /THROUGH MONDAY/... Channel 9/10 water vapor imagery and the 12Z IAD sounding indicate an abundance of mid level dry air across much of the forecast area. That is the reason why so far precipitation has been in the form of drizzle and light rain. A band of more notable rain extends across far southern Maryland but likely won`t make much northward progress through the day. Likely won`t need to make many adjustments to the near term forecast.
Morning surface analysis and satellite observations show the coastal low located off the Carolina coast has stalled. To the north, a broad surface high centered near Nova Scotia continues to drift to the northeast today. The interaction between these two system is resulting in a strengthening baroclinic zone over the Outer Banks where winds are gusting around 35-40 kt. This frontal zone will shift north along the Mid-Atlantic coast through tonight, with models indicating a second surface low is likely to develop east of the Delmarva by tonight. Aloft, two separate cutoff lows (one over the Southeast U.S. and the other over NY) remain mostly separated, with any phasing not occurring until Monday.
The initial band of light rain and drizzle is now west of the Blue Ridge, with a dry slot in between the rain band to the southeast. The latest high res guidance continue to indicate that most of the heavier precip is going to remain south/east of our area. Rainfall amounts have continued to trend downward, now only around a quarter to half an inch (if that), with up to one inch possible southeast of I-95.
Additional rain chances now stand around 40-60 pct for today where it`s not currently raining. Abundant low level clouds and passing showers / periods of light rain will keep highs in the lower to mid 60s this afternoon. The strongest winds are expected this afternoon into this evening. Sustained northeast winds around 15-20 mph, gusting 25-35 mph, and possibly up to 35-40 mph along the immediate Western Shore of the Chesapeake. Winds decrease a bit into tonight, but still gusting around 20-30 mph.
As mentioned previously, the two mid-level cutoffs phase over the Mid-Atlantic Monday afternoon. The surface low east of southern NJ will retrograde closer to the Delmarva coast through Monday evening. This brings a second, though lesser, surge in winds for areas east of the Blue Ridge. Another period of widely scattered showers looks possible Monday morning to afternoon, but again this likely will be focused in areas closer to the low itself (so looking at areas along and east of I-95). A very cool Monday for most as highs struggle to reach the 60s once again. Some peaks of sunshine are going to be possible west of the Blue Ridge where highs could approach 70F in the Alleghenies and south of Staunton.
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.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... The phased upper trough shifts offshore Tuesday into Tuesday night, dragging the coastal low away from the area. Dry and warmer conditions are forecast behind the low`s departure, with highs reaching the lower 70s. Still a bit breezy as northwest winds gust around 20-25 mph. Clearer skies Tuesday night as temps settle in the mid to upper 40s west of the Blue Ridge and 50s to the east.
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.LONG TERM /WEDNESDAY THROUGH SATURDAY/... The synoptic pattern in the extended period remains quite amplified. On Wednesday, a formidable upper trough swings across southeastern Canada into the offshore Atlantic waters. As this occurs, a broad ridge centered over the Southern Plains is expected to approach from the west through the remainder of the work week. This will allow northwesterly flow aloft to prevail. While diminishing in strength, this positive height anomaly should descend upon the Eastern Seaboard by the first half of next weekend. The overall pattern favors dry weather through at least Saturday before a warm advection regime brings rain chances back for next Sunday.
The surface pattern is forecast to be dominated by Canadian high pressure. This ridge is slated to be centered over the Upper Midwest on Wednesday before reaching the Central Appalachians by Friday morning. The caliber of high pressure does weaken in time on its southeastward approach toward the eastern U.S. Temperatures drop to below average for Thursday and Friday with highs in the low/mid 60s (upper 40s to 50s across the mountains). Optimal radiational cooling at night will make for frosty conditions on Wednesday and Thursday nights. The latter night could prove to be more widespread in nature with lows in the low/mid 30s from the Blue Ridge westward. A return flow on Saturday aids in a warming trend for next weekend.
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.AVIATION /13Z SUNDAY THROUGH THURSDAY/... A coastal low tracking up the Mid-Atlantic coast through Monday night is going to produce steady sub-VFR conditions at all terminals. MVFR to IFR CIGs will be commonplace, though gusty winds should keep them in the MVFR category during the daytime (with CHO likely lifting there shortly). Then the ceilings will likely drop again tonight. Periodic showers and light rain moving across the area will drop visibility to 3-5SM, though there does appear to be considerable dry time today. Expect breezy conditions to peak this afternoon with gusts of 25-30 knots. Winds diminish slightly tonight, but still gusting around 20-25 knots.
VFR conditions look to return sometime Tuesday morning to early afternoon as the coastal low finally moves away from the area. Northwest winds gust around 20 knots Tuesday afternoon.
In the wake of a strong cold front, northwesterly winds will prevail on Wednesday and Thursday amidst VFR conditions. Afternoon gusts could near 20 to 25 knots at times before diminishing into the evening to overnight hours.
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.MARINE... A prolonged period of hazardous marine conditions is ongoing and looks to continue through much of the upcoming week.
Gale Warnings are in effect for most of the waters, except the middle to upper tidal Potomac River where SCAs are in effect. Northeast winds are gradually ramping up, with gusts around 30-40 knots in the waters under the Gale Warning and around 25-30 knots in the SCA by this afternoon. The Gale conditions look to slowly come to an end from north to south late tonight into Monday morning, though a second surge of Gales is possible in the middle Chesapeake Monday afternoon.
Elsewhere, Small Craft Advisories will be issued after the Gales expire to cover the long period of gusty winds that continues Tuesday into Tuesday night.
Breezy winds are expected behind a strong cold front. Expect mainly north to northwesterly winds on Wednesday and Thursday with gusts up to 20 to 25 knots at times. This will likely require Small Craft Advisories for much of the waterways through Thursday evening, perhaps longer over the Chesapeake Bay given northerly channeling effects.
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.TIDES/COASTAL FLOODING... Tide levels have remained steady early this morning, though the forecast itself is still tricky given the developing coastal low off the Carolina coastline. Water will continue to surge into the estuary today, becoming trapped by the northeast winds. However, those strong northeast winds will also tend to keep this surge shoved to the south. Nevertheless, minor tidal flooding is expected at many sensitive locations from Annapolis south and at Alexandria.
Models still show a wide range of possible outcomes at high tide today through Monday morning. There is also likely to be a tight gradient of water levels today, as water is pushed out of the northern part of the bay, but piles up in the southern half (along with the Potomac). While the forecast has changed to keep tide levels in minor flood stage, there is still a non-zero chance that moderate tidal flooding occurs this evening in some spots.
On the back end of this system, strong N/NW winds are forecast to push tides out rapidly, potentially leading to blowout conditions. The latest guidance is less suggestive of this outcome however, with high waters levels potentially sloshing back northward and leading to additional minor flooding through midweek.
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.LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Small Craft Advisory until 10 AM EDT this morning for MDZ008. Gale Warning until 6 AM EDT Monday for MDZ008. Coastal Flood Advisory from 8 PM this evening to 3 AM EDT Monday for MDZ014. Coastal Flood Advisory until midnight EDT tonight for MDZ016. Coastal Flood Advisory from 5 PM this afternoon to 10 PM EDT this evening for MDZ017. Coastal Flood Advisory from 4 PM this afternoon to midnight EDT tonight for MDZ018. VA...Coastal Flood Advisory until midnight EDT tonight for VAZ057. Coastal Flood Advisory from 1 PM this afternoon to 4 AM EDT Monday for VAZ054. WV...None. MARINE...Small Craft Advisory until 10 AM EDT this morning for ANZ530- 531-538-539. Gale Warning until 6 AM EDT Monday for ANZ530-531-538-539. Gale Warning until 8 AM EDT Monday for ANZ532>534-537-540>543. Small Craft Advisory until 8 AM EDT Monday for ANZ535-536.
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SYNOPSIS...KRR NEAR TERM...ADS/KRR SHORT TERM...KRR LONG TERM...BRO AVIATION...ADS/BRO/KRR MARINE...ADS/BRO/KRR TIDES/COASTAL FLOODING...KRR/ADS
NWS LWX Office Area Forecast Discussion