Marine Weather and Tide Forecast for Washington, DC

KEY MESSAGES
-1) Temperatures warm through the weekend with a couple opportunities for rain showers.

-2) Surface high pressure builds overhead through midweek with seasonable temperatures expected.

DISCUSSION
KEY MESSAGE 1...Temperatures warm through the weekend with a couple opportunities for rain showers.

Continued warming trend today with clipper system moving in this evening. Temps will rise into the 60s today, but clouds will increase with approaching system. Have continued mention of gusty winds across the Alleghenies this afternoon with tightened pressure gradient. Given wind field, current thinking is below Wind Advisory Criteria. Rain chances in the form of showers increase this evening. Some 00Z guidance has trended up in QPF with these, but given overall limited moisture most areas should average 0.10 to 0.25 inches. Areas in NE MD and along/west of the Allegheny front could see locally higher amounts. Rain showers continue this evening and into the night before drying out by sunrise on Sat. SPC does have NW areas of FA in a MRGL Risk, but given timing of FROPA into that part of the FA is after peak heating think it is a lower end MRGL in coordination with SPC.

Despite the cold frontal passage with this clipper system, a mainly west to northwesterly wind will yield a dry and very well mixed boundary layer Sat. With potential mixing into the 850-750 mb layer, forecast highs push well into the 60s to low 70s. Spotty mid 70s are possible closer to I-64.

Abundant sunshine on Sunday. A warm S to SW wind will bring temps to nearly 20 degrees above avg into the mid to upper 70s with slightly cooler temps in the mtns and in NE MD. Dry conditions expected until Sun night when showers and a t-storm or two are expected to accompany the front.

KEY MESSAGE 2...Surface high pressure builds overhead through midweek with seasonable temperatures expected.

Canadian surface high pressure builds over the FA with seasonable temps expected in the wake of a cold front. There will be a large spread in temps Mon as the cold front departs the area with highs ranging from 40s in the Alleghenies to low 70s in central VA. Precip moves out of the FA by Mon afternoon with dry conditions expected through Tue. Temps continue to cool on Tue as Canadian high pressure builds overhead with highs in the 40s and 50s for most.

A trough pivoting overhead midweek brings our next chance at precip. Models remain uncertain regarding impacts from the trough, but right now have the best chances for rain on Thursday.

AVIATION /06Z FRIDAY THROUGH TUESDAY/
VFR conditions are expected through this afternoon given the influence of surface high pressure. A clipper system arrives this evening into tonight which will bring increasing shower chances. This may yield some restrictions at times through Sat morning. For winds, gradients remain weak which will maintain light southerlies through daybreak. Southwesterlies increase today with gusts to 15 to 20 knots before shifting to northwesterlies behind the frontal system Sat. Winds turn lighter into the night, with LLWS possible in the evening.

VFR conditions much of Sun into Sun evening. Brief MVFR conditions could occur at a few terminals that encounter any heavy shower activity Sun night into Mon morning.

NW winds gust 20 to 25 knots across the terminals on Mon. Sub- VFR conditions are possible Mon morning as precip lingers as a cold front departs the region. VFR conditions return areawide in the afternoon and are expected to continue through Tue. Winds become light overnight become light overnight and remain light on Tue, blowing out of the south.

MARINE
SCAs remain in effect from late this morning into tonight as gusts push to around 20-25 knots out of the SW. Post-frontal northwesterlies actually decrease a bit on Sat before light southerlies return by late Sat, though SCAs may need to be extended into Sat for portions of the waters.

SCAs likely Sun afternoon through Mon night. Winds south to southwest 5 to 15 knots Sun, increasing out of the NW with gusts of 20 knots Sun night. NW winds on Mon gust around 20 knots with SCAs likely, mainly over the Chesapeake Bay and southern Potomac. Winds diminish below SCA criteria Mon night.
Winds shift to southerly on Tue and will remain below SCA criteria throughout the day.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Small Craft Advisory from 11 AM this morning to 5 AM EDT Saturday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM this morning to 5 AM EDT Saturday for ANZ530>543.