Marine Weather and Tide Forecast for Arden on the Severn, MD

NEAR TERM /THROUGH TONIGHT/
An amplified pattern continues over the eastern CONUS. An upper-level gyre with two embedded upper lows was rotating around the Great Lakes and Northeast. The lead upper low was moving across PA toward southern New England as of early afternoon, inducing a triple point surface low pressure in the vicinity of the Delmarva.

Prior to the passage of the surface triple point, a narrow and brief window for convection will exist mainly east of US-15 and south of I-70 until late afternoon or early evening. The best overlap of modest instability (500-1000 J/kg MLCAPE) and shear (35-45 kt 0-6 km bulk shear) will reside over southern MD. As mid-level temps cool, spotty gusty winds or small hail is possible. However, given the brief and modest parameter space, any severe risk seems marginal into early this evening.

A couple of trailing impulses could keep scattered shower activity going near/north of US-50 into the evening, though coverage and intensity of showers will be on a down trend.
Further west (i.e. along/west of the Allegheny Front), upslope showers will likely persist well into the night, with a few wet snowflakes or sleet pellets possible above about 4000 feet.

Low temps will range from the upper 30s over the highest peaks to the mid 50s in the major city centers.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
The trailing upper low associated with the aforementioned gyre will pivot north across NY/PA on Friday. This will lead to the passage of a secondary cold front and result in the potential for a few pop up showers. However, the main story with this late season low will be the wind. Gusts of 25 to 35 mph are likely across much of the area during the day on Friday as a late season nor'easter takes shape near New England.

Winds will become lighter Friday night as high pressure builds toward the Mid-Atlantic. High pressure will pass to the north Saturday with dry weather and below normal temperatures. A warm front will develop well to the south and west of the CWA Saturday night, and some high clouds may begin to increase late.

LONG TERM /SUNDAY THROUGH THURSDAY/
Ensembles and deterministic model guidance has a nearly zonal upper-level flow building over the region on Sunday and remaining in place through the early parts of next week. A warm front/pseudo-stationary front will likely be positioned somewhere over the southern Mid-Atlantic/northern parts of the SE US. Shortwave energy moving along the nearly zonal flow will generate sfc lows along the front leading to multiple rounds of showers and thunderstorms being possible. As of right now, guidance has our region on the northern edge of this setup with the boundary far enough south that we may only see a few passing showers Sunday through Monday. If front ends up being further north than what models are showing, then we could be in for another active week of rain especially if parts of our region sneak into the warm sector located south of the front.
Below normal temperatures are favored to continue if the region remains on the cool side of the boundary.

The zonal flow aloft is forecast to start to break down sometime Tuesday into Wednesday as an upper-level trough starts to approach from the Great Lakes region. Some models have a coastal low forming along the front to the south and lifting northeast through parts of our region. This will be the best chance for widespread precipitation with the best chances for precip being Wednesday through Thursday.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR conditions had returned to most of the TAF sites as of 18Z as a warm front lifts passed and a cold front quickly follows.
This is shifting winds around to the west, with gusts of 15-20 kts. Iso TS possible mainly SE of DCA. SHRA activity should diminish into this evening, though some iso light activity could linger until a little after sunset. Wind gusts will subside this evening, as well.

VFR conditions and gusty NW winds are expected Friday. Gusts could exceed 30 kts at times. A couple of pop up showers are possible. Winds will become lighter Friday night, then gusts resume during the day Saturday but at slightly lower speeds as high pressure passes to the north. Winds slacken again after dark Saturday night while remaining NW.

Sub-VFR conditions will be possible at times if the region experiences showers and thunderstorms Sun-Mon. The best chance for aviation restrictions in the long term will be Tue-Wed.

MARINE
A frontal system will swing through by this evening shifting winds to the west. A few showers and thunderstorms are expected through early this evening. Gusts around 20 knots are likely along the tidal Potomac River into the mid Chesapeake Bay area, with gusts lingering on the bay overnight. Winds increase areawide during the day on Friday with gusts to 30 knots possible. Winds will become lighter Friday night, then increase again during the day on Saturday.

Near SCA conditions will be possible during the end of the long term period (Wednesday - Thursday) due to a passing coastal low.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Coastal Flood Advisory until 4 PM EDT this afternoon for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 8 AM to 6 PM EDT Friday for ANZ530- 531-539.
Small Craft Advisory from 5 PM this afternoon to 6 PM EDT Friday for ANZ532-540.
Small Craft Advisory until 6 PM EDT Friday for ANZ533-534-537- 541-543.
Small Craft Advisory until 8 PM EDT this evening for ANZ535- 536-542.
Small Craft Advisory from 11 AM to 6 PM EDT Friday for ANZ535- 536-538-542.