textproduct: Baltimore/Washington

SYNOPSIS

High pressure will move offshore through early Monday as a cold front crosses the Mid-Atlantic. An area of low pressure will develop off the Carolinas and move northeast out to sea Monday night. High pressure will return Tuesday into Wednesday, then another cold front will cross the region Wednesday into Wednesday night. High pressure will briefly build over the area again Thursday into Friday before another cold front approaches next weekend.

NEAR TERM /THROUGH MONDAY/

As surface low pressure develops off the Southeast coast tonight, low level clouds will thicken east of the Blue Ridge. This will keep overnight lows in the 40s east of the Blue Ridge, and to the west where skies should be clearer lows drop to the 30s.

Rain could reach southern MD, possibly to the I-95 corridor from the DC Metro south, late tonight. Going toward daybreak, some light rain is possible over most of the DC Metro and possibly up toward the southern Baltimore metro.

SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/

As the aforementioned low pressure system tracks along the Carolina coast, precipitation chances linger for the I-95 corridor and into southern Maryland Monday morning. Dry conditions and increased cloud cover can be expected elsewhere. By Monday afternoon, low pressure and any associated rain should pull away to the east with gradual clearing expected.

A cold front is progged to cross the area Monday night. This will bring winds out of the northwest Monday night into Tuesday as high pressure builds in from the Ohio Valley. Some gusty winds are possible immediately behind the front Monday evening, especially over the higher terrain where breezy conditions could linger through early Tuesday morning.

Downsloping flow is favorable to bring down some dry air Tuesday, so depending on how strong the winds are Tuesday could be a Fire Wx day (see section below).

High temperatures will be in the 50s and 60s Monday and Tuesday with overnight lows dropping into the 30s and 40s.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

An area of low pressure will slide by well to our north on Wednesday, pushing a dry cold front through the region into Wednesday night. Ahead of this boundary, gusty southerly flow is expected across the region, with gusts around 20-30 mph. A very dry air mass ahead of this front will yield very little moisture over the region, with only a slight chance of precip in the forecast over the Alleghenies at this time. Coming off of Tuesday's fire weather concerns, those will linger into Wednesday as well. See details in the Fire Weather discussion below. Temperatures will be above average for this time of year, reaching the upper 60s to near 70 for most (50s to low 60s in the mountains).

Behind this system, another dry day can be expected Thursday under the influence of high pressure. Expect temperatures to come back down to the upper 50s to low 60s (mid 40s to low 50s in the mountains).

By Friday, a more substantial upper trough starts to dig towards the Ohio Valley as high pressure retreats offshore. A stronger frontal passage is expected late Friday into Saturday, but exact timing still needs to be worked out as we get closer in time. At first glance, this system seems like it should be better connected to moisture coming out of the Gulf of America, and thus should result in some rain across the region. However, at this stage, it is too early for any exact details. Any shift in the surface and upper- level features at play could yield another dry frontal passage, which could lead to other hazards. So for now, this is just something to keep an eye on over the coming days.

AVIATION /01Z MONDAY THROUGH FRIDAY/

VFR conditions continue through tonight as high pressure moves offshore and a cold front approaches from the west. Winds become light west/northwest late tonight into Monday morning. Some rain may approach CHO/DCA from the southeast, but restrictions should be very limited and brief if they occur at all. Given the low probabilities, not included in the 00Z TAFs.

On Monday, low pressure to the south will yield increased cloud cover and lingering precipitation chances mainly east of I-95 during the morning hours. Not expecting any restrictions with this precipitation largely being east of all TAF sites.

The cold front will pass by Monday evening bringing winds out of the northwest and VFR conditions. Gusts of 15-25 kts are possible with the frontal passage, possibly briefly slightly higher Monday evening with more occasional gusts overnight. VFR and northwest breezes gusting 15-20 kts are anticipated Tuesday with lighter winds Tuesday night as high pressure builds.

VFR conditions are expected Wednesday through Friday. There will be a notable cold frontal passage late Wednesday into Wednesday night with an outside chance of a shower at MRB, however. This front will shift winds from the south Wednesday to the northwest Wednesday night through Thursday evening. Daytime speeds of 10-15 kts are anticipated, with gusts of 20-25 kts especially during the day on Thursday when a few gusts over 30 kts are possible. Winds turn back to the south Friday.

MARINE

Light winds become northeast by late evening, then west to northwest by Monday morning. A cold front will cross by late Monday afternoon kicking up winds out of the northwest. A brief period of sporadic gusts 30-35 knots can't be ruled out immediately behind the front with forecast soundings indicating such winds around 1500 feet above the surface with a very shallow stable layer and notable pressure rises in the evening. Some of these stronger gusts may linger over the wider waters overnight. Residual SCA caliber northwesterlies are expected through midday Tuesday, possibly a bit longer. Lighter winds are expected Tuesday night as high pressure builds.

Southerly flow ahead of an approaching cold front Wednesday could result in gusts of 15-20 knots. The cold front should come through mainly dry Wednesday night, turning winds to the northwest. Speeds will increase with gusts of 20-30 knots possible through Thursday, diminishing Thursday night. There is an outside chance of gale conditions late Wednesday night into Thursday if the front comes through a bit stronger. Winds turn southerly Friday.

FIRE WEATHER

A dry frontal boundary will push through the region on Monday, with a very dry air mass following in its wake on Tuesday. Winds will be out of the W to NW on Tuesday with gusts around 15-20 mph, mainly north of the I-66 corridor. Further south, and down into the Shenandoah Valley, winds will be closer to 8 to 14 mph or so. At any rate, this will be just enough wind, that when paired with RHs potentially into the teens and low 20s in a reasonable driest case scenario, causes some concern for potential hazardous conditions for wildfire spread. Recent rains have certainly been beneficial, but by this point we will be several days removed from that. Some breezy days have further allowed for drying of fine fuels in the region, especially when paired with the long term dryness. While this isn't a slam dunk day in terms of high end fire weather, it is certainly looking like it could be one of the driest days we have seen this fall so far.

Winds will pick up substantially on Wednesday and turn out of the south. Typically this should result in a substantial increase in RH, but that isn't always the case, as will be seen on Wednesday. Current forecasts call for afternoon RH values in the mid to upper 30s in the valleys, owing to a very dry air mass in the source region of that southerly flow. When paired with 20-30 mph southerly wind gusts, this could result in another potentially hazardous day for wildfire spread.

LWX WATCHES/WARNINGS/ADVISORIES

DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 7 PM Monday to 1 PM EST Tuesday for ANZ530>543.