Washington, DC 20542 Weather

This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and I-95 corridor through central Maryland, northern Virginia, and District of Columbia.

Day one: Tonight

No hazardous weather is expected at this time.

Days two through seven: Friday through Wednesday

No hazardous weather is expected at this time.

Spotter information statement

Spotter activation is not expected at this time.

What has changed

No significant changes to the forecast outside of some tweaks to temperatures for today. Benign weather continues through Halloween weekend before changes next week.

Key messages

- 1) Very warm conditions today, with seasonable temperatures an dry conditions for Halloween weekend.

- 2) Rain chances will likely hold off until the second half of next week.

Discussion

KEY MESSAGE 1: Very warm conditions today, with seasonable temperatures an dry conditions for Halloween weekend.

A weak cold front is expected to cross the area this morning into midday bringing some spotty sprinkles to the highest ridges of the Alleghenies. Elsewhere, dry conditions will prevail with passing mid and high level cloud cover. High pressure will return later this afternoon and into the upcoming weekend ahead. The gradient between the departing front and incoming high pressure will yield west to northwest downsloping winds up to 25 mph.

Expect above normal temperatures as a result of the downsloping east of the mountains. Compressional heating from the Alleghenies, Blue Ridge, and Catoctins should push highs in the low to mid 70s (60s mountains). Locations south of DC and down toward Charlottesville have a shot to briefly touch 80 degrees given the very dry air ahead of and behind the front.

Cooler temperatures return tonight into the upcoming weekend. Expect much more seasonable weather for both Halloween Saturday and Sunday. Highs both days will push into the 60s with overnight lows in the 30s and 40s. Expect more sunshine Saturday compared to Sunday given the high nearby. Cloud cover will increase Sunday afternoon and night as a shortwave trough passes south of the area. This trough may touch off a shower or two Sunday night although most will remain dry given the residual mid-level dry air with high pressure nearby.

KEY MESSAGE 2: Rain chances will likely hold off until the second half of next week.

Models are arriving at better agreement that mid level ridging will build along the east coast during the first half of next week. A shortwave trough may cross the area Monday before the ridge takes hold, and there is still an outside chance a few showers could occur as it passes. At a minimum, expect cloudier conditions. Temperatures will likely climb Tuesday and Wednesday, with highs reaching the 70s for many areas.

A deep trough will approach from the west the second half of the week. A low pressure system will likely be lurking over the Bahamas, and some guidance suggests this system, or at least some of its moisture, could be swept northward into the Mid Atlantic ahead of the trough. While the details remain uncertain, expect increasing rain chances in the Wednesday through Friday period.

Aviation

Prevailing VFR conditions are forecast to continue through the upcoming weekend as high pressure builds into the region. A dry cold front will cross the terminals later this morning and into the afternoon leading to some passing mid and high level cloud cover. Winds will kick up in the wake of the front out of the west and northwest with gusts between 20 to 25 kts. Highest gusts will be at terminals near the waters and along the ridges. Winds will gradually diminish Saturday morning into Saturday afternoon as high pressure settles overhead. Northerly winds will prevail through Saturday night at less than 10 kts.

VFR conditions are expected Sunday into Monday as high pressure continues to meander nearby. Winds will turn to the south and southeast and less than 15 kts. Significant weather is unlikely Monday and Tuesday as high pressure moves eastward. However, some low chances of sub-VFR ceilings exist Monday or Monday night depending on how the weather pattern evolves.

Marine

A weak/dry cold front will push across the waters this morning with high pressure building south over the region this weekend. SCA conditions are expected from late this morning through early Saturday morning, especially over the open waters. This is largely due in part to northerly channeling. Winds diminish below SCA level Saturday morning before falling back below sub-SCA levels Saturday afternoon. Sub-SCA conditions look to continue Sunday into Monday with wedging high pressure meandering nearby. Winds will change to the south and southeast as high pressure sits north and east of the area. Speeds will generally be between 5-10 kts. Showers may impact the middle and southern waters Monday afternoon as a wave of low pressure approaches from the south and west. Better chances for rain by the end of next week.

Tides/coastal flooding

Offshore flow develops behind a cold frontal passage this morning allowing tidal anomalies to drop over the next few days. Winds turn back to the south Sunday afternoon leading to modest rises in anomalies heading into early next week.

Watches, warnings and advisories

DC: None. MD: Small Craft Advisory from 10 AM this morning to 9 AM EDT Saturday for MDZ008. VA: None. WV: None. MARINE: Small Craft Advisory from 10 AM this morning to 9 AM EDT Saturday for ANZ530>543.