textproduct: Baltimore/Washington

SYNOPSIS

High pressure will build overhead through Thursday before moving offshore Friday. Above normal temperatures are expected along with an increasing trend in humidity. A cold front will slowly pass through the area this weekend and it will stall out nearby early next week.

NEAR TERM /THROUGH TONIGHT/

Weak surface high pressure will build overhead today while an upper-level trough axis moves off to the east. Subsidence behind the departing upper-level trough along with a downsloping westerly flow will allow for dry conditions along with sunshine and above normal temperatures. Highs will be in the mid to upper 80s for most locations (70s in the mountains). Humidity will be on the lower side with dewpoints in the 50s and 60s for most areas.

High pressure will bring dry conditions tonight, and it will turn out cool due to light winds and dry air. Min temps will be in the 50s and 60s for most areas. A few high clouds will move into the area in a zonal flow aloft.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Weak high pressure begin to slowly move offshore Thursday while weak ridging builds overhead. Subsidence with the weak ridging along with sunshine will allow for a hotter afternoon, with highs in the upper 80s to lower 90s for most areas. Humidity will creep up a bit, but remain on the lower side with dewpoints in the 50s and 60s. Heat indices will top off in the lower to middle 90s near and east of 95 into central Virginia with 80s to near 90 elsewhere.

More dry conditions are expected Thursday night, but it will be a bit warmer with lows in the 60s and 70s.

Closed upper-level low pressure will slowly drift through the Plains and into the Midwest Friday through Friday night while high pressure builds over the Atlantic. The south to southwest flow in the low-levels will increase and this will advect in plenty of moisture from the Gulf Coast states. At the same time a cold front will remain to our north, but a surface trough/weak low pressure is likely to build overhead. The increased lift and instability will increase the chances for showers and thunderstorms, especially during the afternoon and evening. Warm and humid conditions will persist Friday night with some fog possible.

LONG TERM /SATURDAY THROUGH TUESDAY/

An upper-level low will shear apart as it approaches the area Saturday before most likely passing through the area Sunday. High pressure will build off the New England coast behind this system and it will likely send a backdoor boundary through our area. Timing is uncertain, but it is most likely to pass through Sunday night into Monday.

Ahead of the boundary, warm and humid conditions will persist, and plenty of moisture will continue to stream into the area. Latest EPS shows PWATS around 1 to 2 standard deviations above normal. The moisture combined with instability on the warm side of the boundary will likely bring showers and thunderstorms, especially during the afternoon and evening hours each day. With a relatively light flow, heavy rain combined with already saturated soil may result in instances of flooding. Will continue to monitor details as it gets closer.

Cooler marine air may cause more stability for Monday and Tuesday behind the backdoor boundary. However, it will likely remain close for unsettled conditions to persist.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Patchy fog may cause MVFR conditions early this morning, but confidence is too low to include in the TAFS. Otherwise, VFR conditions are expected through Thursday night along with light winds.

Moisture will return Friday and a few showers and thunderstorms are possible in the afternoon and evening. More showers and thunderstorms are likely for Saturday and Sunday as moisture continues to stream into the area. Low clouds and possible fog may result in subVFR conditions.

MARINE

Weak high pressure will build overhead through Thursday, bringing dry conditions and light winds.

A southerly flow will increase for Friday into the weekend. This will increase the chances for showers and thunderstorms. Winds may approach SCA criteria for portions of the waters, but confidence is low.

TIDES/COASTAL FLOODING

The more sensitive tidal sites could continue to hit action stage during the higher of the 2 high tide cycles the next couple of days. But overall, anomalies will slowly drop.

LWX WATCHES/WARNINGS/ADVISORIES

DC...None. MD...None. VA...None. WV...None. MARINE...None.