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000 
FXUS61 KLWX 210859
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 AM EST Thu Nov 21 2019

.SYNOPSIS...

High pressure will pull offshore tonight. A cold front will 
follow for Friday. Low pressure is expected to develop over the 
Mid-Mississippi Valley Friday night, then track across the area 
this weekend. High pressure will likely return early next week 
before another area of low pressure develops to the west by the 
middle portion of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

An area of high pressure overhead today will move to the East 
Coast by this evening. Today will start with a few clouds with a
west-northwest wind, but then quickly become blanketed with 
mid-level and high clouds and a southwest to southerly wind by 
later this afternoon ahead of an approaching cold front. 
Temperatures will be near average this afternoon and slightly 
above average tonight. 

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...

A cold front will slice across our CWA Friday. Model guidance shows 
the frontal passage in western Maryland to be around 9 am or mid-
morning on Friday and across southern Maryland to be around 3 pm or 
mid-afternoon on Friday. Although no thunderstorms are expected with 
this frontal passage, rain showers are expected to accompany the 
front from west to east. It seems that there could be more 
persistent shower activity across the Potomac Highlands due to the 
front and upslope wind, and across the Virginia Piedmont to southern 
Maryland as there may be slightly more instability in these regions 
and less of an influence from downsloping wind ahead of and along 
the front. Rain amounts will probably range between one quarter to 
one half inch at higher spots.  

As the front makes its way farther south toward the Virginia and 
North Carolina border Friday evening, noticeably cooler and drier 
air will filter in from the northwest due to high pressure building 
into the region. High pressure will remain in control of the region 
Saturday by shoving this cooler air southward along and east of the 
Blue Ridge Mountains. As we venture into Saturday afternoon into 
Saturday night, some increasing moisture and warmth on the back side 
of the high will lead to areas of rain arriving from the
southwest.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...

Low pressure will be deepening rapidly as it moves offshore Sun
morning with rain showers ending by late morning. Gusty NW winds
will take over with gusts 30-35 mph expected. High pressure will
gradually build over the area late Sunday night through Tuesday.

The latest 00Z ECMWF trended significantly weaker and faster
with next storm system fcst to impact the region mid next week
while the 00Z GFS and GFES remained more consistent moving a
strong storm system over the Upper Midwest. Needless to say, it
appears a lot of uncertainty in the fcst for the second half of
next week. Temperatures are likely to trend cooler than normal
for the second half of next week.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...

VFR conditions through tonight as high pressure overhead slowly 
moves to the East Coast. A cold front will slice across the region 
Friday. Rain showers will develop at the terminals with higher 
amounts possible at the CHO, and DCA terminals. MVFR conditions 
possible with these showers. Winds will increase from the southwest 
ahead of the front and then from the northwest behind the front.
VFR conditions reture Friday night and much of Saturday. Some areas 
of rain could move into CHO, MRB and IAD Saturday afternoon and 
reduce conditions to MVFR or IFR once again. Other terminals will 
follow Saturday evening with an approaching low pressure system. 

Gusty NW winds expected Sun into Sun evening.

&&

.MARINE...

Small craft advisories are in effect through 6am this morning. Small 
craft advisories may be needed Friday ahead of the front then again 
early Saturday behind the front.

Small Craft Advzy conditions expected Sun-Sun night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EST early this morning for 
     ANZ533-534-537-543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...KLW

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