Monday, December 18, 2017, 12:18 AM EST
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Area Forecast Discussion
Valid At
Wed, Dec 31, 7:00pm EST
FXUS61 KLWX 171958

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
258 PM EST Sun Dec 17 2017

A weak boundary overhead will lift to the north as a warm front
tonight into Monday. An upper level disturbance will approach 
the area from the west Monday afternoon and evening. This 
disturbance could bring some light precipitation to the 
Appalachian Front later Monday. High pressure will build in 
briefly before the next storm system scoots by to our south 
during the middle of the week. 


Satellite imagery shows a lot of mid-level and high cloud cover
across the region this afternoon. Radar imagery shows a lot of 
echos across the region, as well. However, due to temperatures
being in the upper 40s and dewpoint temperatures being in the
lower 30s, there is a lot of dry air in place...especially
southern and eastern portions. Therefore, any precipitation that
is falling is not reaching the ground. Still, there could be a
couple of rain drops or perhaps a sleet pellet or two across the
northern tier and nearest the highest terrain later this
afternoon into this evening. Chances remain minimal. As for
temperatures, we have nudged upwards a little in our forecast
due to a persist light southeast wind and lack of low cloud

The boundary, providing a safe haven for this cloud cover and
limited precipitation, will lift north as a warm front tonight.
Any precipitation chances will end from south to north as the
front continues its progress. Low temperatures will bottom out
near or slightly above freezing.



As a warm front pushes to the north Monday, so do the milder
temperatures will highs about 5 degrees warmer than Sunday. A
light persistent southwest wind will aid in this milder trend.
By Monday afternoon into Monday evening, clouds and precipitation
will return with the bulk of any precipitation remaining light 
and mainly confined to the Appalachian Front in the form of 
light rain or drizzle. A leeside trough of low pressure should
set up just to the east of the Appalachian spine, thus, allowing
for this precipitation to occur with the help from a weak mid-
level disturbance.

Tuesday should be even milder yet with highs ranging from the
middle 50s to the middle 60s widespread across the region. A
persistent southwest wind and a little added sunshine during the
day should aid in this. Tuesday night will be about the same as
Monday night with low temperatures dropping into the middle to
upper 30s for the most part.


Southern stream shortwave energy will be approaching the Mid-Atlantic
region on Wednesday into Wednesday night. Guidance suggests that the
forcing will stay south of us, but showers associated to this system
could reach the southern counties of our CWA. Still to be determined
in more detail is timing and p- types.

A ridge of high pressure builds over the region on Thursday and into 
Thursday night bringing a period of dry weather. Sometime on Friday 
a warm front will push through, followed by a cold front on Saturday.
Models suggest that Friday will remain on the drier side while Friday
night we might see showers ahead of the front, but it all depends
on the timing of it. Saturday's PoPs are higher with the front moving
through the region from the west. Uncertainty exists on Sunday's
weather depending on how close to the area the front stalls. 


VFR conditions at all terminals. We can't rule out a brief drop
to MVFR in any isolated rain or sleet showers near the MRB
terminal. Winds generally southeast less than 5 knots through
this afternoon, becoming light and variable tonight. VFR
conditions Monday through Tuesday night. Winds becoming
southwest 5 to 10 knots Monday and Tuesday with light and
variable winds Tuesday night.

Sub-VFR conditions possible on Wednesday as forcing moves south of
the area that could bring some showers to the terminals. VFR conditions
expected Thursday and into Friday.


No marine hazards through Tuesday night. Winds southeast 5 to 10
knots through this afternoon, becoming light and variable
tonight. Winds southwest 10 knots Monday and Tuesday then light
and variable each night.

Winds are expected to stay below small craft advisory threshold Monday
into Tuesday. Winds could increase Tuesday night into Wednesday behind
a front, requiring a small craft advisory over the waters. 





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