Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 150228
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
928 PM EST Wed Feb 14 2018

.SYNOPSIS...
Very mild weather will persist through Thursday night. A cold
front will then cross the area Friday morning. An area of low
pressure will affect the area Saturday night. High pressure will
return briefly Sunday into Monday before another frontal system
approaches for the middle part of next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Warm advection will continue through the overnight hours with
scattered rain showers spreading eastward. Rainfall amounts will
be light, perhaps up to one tenth of an inch in places. These
rain showers will move across the Chesapeake Bay and the
Delmarva later in the overnight toward Thursday morning. Some
low stratus clouds could ensue later overnight with a chance for
some patchy fog late and early Thursday.

As for the remainder of Thursday, some weak upper level energy
will slide across the region and bring a continuation of cloud
cover during the day. Light to moderate southwesterly winds will
usher in milder Spring-like air into the region, resulting in
high temperatures Thursday pushing 70 degrees in most places.
Dewpoint temperatures will also be on the rise Thursday with
values pushing through the 40s into the lower 50s. This increase
in warmth and moisture will aid in fueling the next batch of
rain showers later in the day and primarily along the
Appalachian Front and adjacent to the Mason-Dixon region.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Rain showers will continue Thursday night into Friday morning
due to a strong cold front that will move across the area Friday
morning. Rainfall amounts with this second round are expected
to be in the 0.25 inch in southeast MD to 2.5 inches in the far
NW. WPC excessive rainfall outlook has area west of I-81 in a
marginal threat and western Alleghany county in a slight risk.
FFG from the MARFC is very low over western Alleghany for some
unknown reasons. This area missed the heavy rainfall that fell
this past weekend. Showers will taper off by late Fri. Expect
calendar highs to occur just before fropa late Thu night with
temperatures dropping all day Fri. Strong high pressure will
build from west to east into the region behind the frontal
passage Friday afternoon through Friday night. Thus, southwest
winds will shift to northwest and become gusty. Temperatures
will also fall steadily and quickly Friday morning through
Friday night.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Saturday starts out dry as high pressure centered over New
England moves east and a front stalls to our south. A wave of
low pressure will track through the frontal boundary and will
impact us later on Saturday. Guidance have become in better
agreement to overspread the region with precipitation on
Saturday afternoon into the night with rain and snow possible.
The uncertainty remains on temperatures at the low and mid
levels, with the potential for sleet, freezing rain as well...
and even if ground temperatures will be cold enough to allow for
accumulations. The track of this system will impact the type of
p-type observed over our CWA. At this moment QPF amounts are
between a quarter and three quarters of an inch. In summary,
there is the potential for wintry precipitation on Saturday
afternoon into the night but it is too uncertain to determine
local impacts.

High pressure builds overhead on Sunday and remain in control into
Monday as it moves offshore. A warm front will lift north on Monday
night and a cold front will stall over our region with waves of low
pressure moving through it, therefore unsettled weather expected
Monday night into Wednesday. Temperatures will be warm, so no
concerns about wintry precipitation at this moment.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Developing MVFR cigs and vsbys late tonight at all TAF sites
with potential for IFR conditions at KMRB and KMTN late
tonight. Conditions improve rapidly Thu morning.

VFR conditions are expected during the first part of the day
Saturday. Conditions could rapidly become sub-VFR Saturday
afternoon and into the night with precipitation overspreading
over the terminals. There are concerns with p-type. VFR
conditions return Sunday and into Monday.

&&

.MARINE...
Winds are expected to strengthen Thursday with SCA conditions
expected Thursday through Friday night.

Winds are expected to be below SCA criteria from Saturday into
Monday, so no small craft advisory expected.

&&

.CLIMATE...
Unseasonably warm weather is expected on Thursday. While temps
will be over 20 degrees above normal, it will be difficult to
top the record highs in Baltimore and Washington. However, the
record highs at Dulles could be smashed. Below are the current
record highs for Thursday February 15:

SITE  RECORD MAX  RECORD MIN
DCA   77 in 1949  52 in 1909
BWI   77 in 1949  51 in 1949
IAD   68 in 1982  44 in 1984 and 1967

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 10 AM to 6 PM EST Thursday for
     ANZ530>543.

&&

$$
SYNOPSIS...KLW
NEAR TERM...KLW
SHORT TERM...KLW
LONG TERM...BJL
AVIATION...BJL/KLW
MARINE...BJL/KLW
CLIMATE...



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