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Area Forecast Discussion (AFD)

Issued by Baltimore/Washington (LWX)

FXUS61 KLWX 251443

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
943 AM EST Sun Feb 25 2018

A stationary boundary draped across southern Virginia will lift 
northward today as a warm front. A cold front will approach from the 
west and cross the area by this evening. High pressure will then 
build in over the region, migrating off the Mid Atlantic coast by 
midweek. A broad area of low pressure will approach the Great Lakes 
region on Thursday, bringing unsettled weather to our region through 
weeks end.


Dense Fog Adv was extended for S MD and adjacent waters until
11am. Main channel of showers moving through the forecast area 
today... mainly this morning. Have adjusted the forecast based 
on the latest models and trends. Went with a combo of the models
that have been doing best most recently for high temps today, 
including NAM, NAMNest, Euro, Hi_Res ARW...those which you 
would expect would do best in damming situations. Improving 
conditions today.


High pressure continues to move eastward over the Mid Atlantic on 
Monday, with a shortwave trough crossing overhead and pressing off 
to our east by Monday evening. This will help skies to finally start 
to clear by Monday afternoon, bringing a welcome return of some 
sunshine. Did keep slight chance POPs in the gridded forecast for 
the first half of Monday for our extreme southern zones as some 
guidance wants to keep the frontal boundary just close enough to 
have the possibility of light shower activity for these areas. 
Temperatures remain above normal on Monday, with highs in the middle 
to upper 50s. High pressure will settle overhead Monday night, 
coupled with light winds, this allow temperatures a good chance to 
radiate under mostly clear skies. Middle to upper 30s will be 
prevalent in the metro areas, with lows at or slightly below 
freezing along and west of the Blue Ridge. Clear and dry conditions 
continue Tuesday and Tuesday night as high pressure dominates the 
region, migrating off the Mid Atlantic coast by Tuesday night. Highs 
on Tuesday will be in the upper 50s to near 60 degrees, with lows 
Tuesday night in the upper 30s to near 40 degrees.


The extended portion of the forecast will start out with high 
pressure moving offshore. Warm advection in the return flow will 
provide enough lift for scattered showers to arrive during the day 
Wednesday. The warm front will approach the forecast area Wednesday 
night, and arrive on Thursday as mid level energy runs through 
rather fast flow. Therefore, PoPs will spread from central 
Virginia across the entire area by Thursday. Temperatures will 
be mild for the period.

A deep cyclone will be developing in the Great Lakes/Midwest 
Thursday, which will be sending a moisture-rich cold front across 
the area Thursday night, with some precip likely lingering into 
Friday. Believe that rain will be the dominant type with this 
system; cold air will be rushing in Friday PM on gusty northwest 
winds after the precip departs. This could provide some upslope snow 
showers to the Appalachians Friday night.

High pressure will be building across the area Saturday as the 
deepening cyclone continues northeast.


Challenge between fluctuations between all flight categories of
restrictions this morning, but the trend is up for both visby 
and cigs today. A cold front will approach the terminals midday,
moving east of the area by around 26/00z. As a result, winds 
will veer from the south this morning, to the west southwest 
this afternoon, and out of the northwest by this evening. Ahead 
and along of the front, winds will gust to around 20 knots 
during the day, along with MVFR/IFR conditions as 
-SHRA moves over the terminals. VFR conditions return in the 
wake of the front this evening, continuing through the first 
half of the work week as high pressure builds over the region, 
promoting light winds and only mid to high level clouds.

Scattered showers will be near the terminals Wednesday, mainly 
to the west. While flight restrictions will be possible, 
confidence is low. The chances increase sharply Thursday as a 
warm front heads north toward the terminals.


Areas of dense fog over the adjacent waters to southern Maryland
this morning. Also some wind gusts of 15 to 20 kt with a
leading edge of showers moving through the same area this 
morning. SCA conditions expected this afternoon as a warm front 
lifts northward in to the area and a cold front approaches from 
the west. Have left the upper portion of the Bay out of the SCA 
at this time as not expecting the warm front to travel this far 
north, thus keeping wind gusts down in these areas. The cold 
front will sweep through the waters this afternoon, potentially 
accompanied by some gusty showers. High pressure builds over the
waters through the first half of the work week, resulting in 
light winds over the waters with no headlines anticipated.

Small Craft Advisories not anticipated Wed or Thu either, due
mainly to poor mixing in vicinity of a warm front and complex
storm system.


MD...Dense Fog Advisory until 11 AM EST this morning for MDZ016>018.
VA...Dense Fog Advisory until 11 AM EST this morning for VAZ057.
MARINE...Small Craft Advisory until 6 PM EST this evening for