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FXUS61 KLWX 080908

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
408 AM EST Sun Dec 8 2019

High pressure will shift offshore of New Jersey today. Low 
pressure will develop over the central United States and lift 
into the Great Lakes through Monday. A warm front developing 
east of this area of low pressure over the Carolinas is expected
to lift northward across the Mid-Atlantic on Monday. The 
aforementioned low will drag its trailing cold front through the
region Tuesday into Wednesday. Strong Arctic high pressure will
build from the Great Lakes toward the Mid-Atlantic Wednesday 
night through Friday, then shift offshore of New England through
Saturday as low pressure develops over the southeastern United 


High pressure will be moving offshore today from the southern 
New England coast. During this time a low pressure system will 
be moving across the Great Plains ahead of a mid/upper level 
trough. Southerly flow will be settling over our area today 
allowing for warm and moist air advection. Temperatures will be 
in the mid to upper 40s over most of our area. 

Clouds will thicken into Sunday night as a warm front 
stretching across the Carolinas lifts north and into our region 
on Sunday night. Also, the low pressure system over the Great 
Plains will be moving NE towards the Great Lakes. Warm and moist
air advection ahead of this system and the warm front to our 
south will bring rain and/or drizzle late tonight beginning over
the southern and western section of our CWA... mainly southern 
Maryland and regions west of the Blue Ridge. 


Deepening low pressure system will be approaching and moving 
through the Great Lakes Monday into Monday night as its 
associated cold front approaches from the west. Isentropic lift 
and mid to upper level jet dynamics will bring rain into our 
region early on Monday, with the more widespread rain during the
day. Then, rain showers will continue into Monday night. PoPs 
will be higher over the NE section of our CWA during this time. 
PWAT values will be between an inch to 1.25". 

Chance of rain showers continue Tuesday ahead of the cold 
front, which will be moving across our area through the day. 
Guidance is in agreement that precipitation will continue over 
our area after fropa and remaining into Tuesday night. A 
changeover from rain to snow is possible over areas near and 
west of I-95 with NW flow and cold air advection. Confidence is 
not very high but some ensemble members are hinting this mainly 
at higher elevations. 

Warm air advection will allow temperatures to become above 
normal Monday into Tuesday. High temperatures will be in the 50s
and 60s. Lows will be in the 40s and 50s on Monday night, and 
much cooler behind the front on Tuesday night. 


Active weather will be pulling away from the region early
Wednesday as a frontal system pushes east off the coast. Some
rain or mixed precipitation may linger early, though models
continue to differ on timing of the end of precip and arrival of
temperatures cold enough to support snow. Thus, confidence in
any snow remains quite low. Otherwise, much colder air will rush
across the region Wednesday, with temperatures remaining fairly
steady in the 30s and 40s before falling into the 20s Wednesday
night as Canadian high pressure builds overhead. 

The frontal boundary will not get far to our south, so while
Thursday is most likely to be cold but dry, we will need to 
watch waves of low pressure pushing northeastward along the 
Carolina coast. 

By Friday, the odds of a wave lifting northward into the area
increase, so have included chance pops with mixed precip across
the region. Odds are not high, but guidance has become
increasingly inconsistent. 

Saturday is more likely to be an active day as most guidance
supports another wave of low pressure rising northeastward
across the region. Temperatures are more likely to moderate, so
at least near I-95, rain is more likely. However, further
inland, mixed precip will remain possible due to cold air


VFR conditions are expected to continue through Sunday evening 
with high pressure in control. Periods of sub-VFR conditions 
possible late Sunday night into Tuesday night with rain and/or 
rain showers moving over the terminals associated to a low 
pressure system and its cold front that will approach and move 
across our area during this time.

Sub-VFR conditions may linger early Wednesday as a cold front
slides off the coast and rain potentially ends as a little snow.
Dry and VFR conditions should prevail Wednesday night and


Winds will remain below criteria through Sunday night as high 
pressure remains in control. A warm front will moves across the 
waters on Monday but winds will remain below criteria through 
the day. Winds will increase late on Monday and remain above 
criteria through Tuesday night. A Small Craft may be needed 
during this time. 

Small Craft Advisories are likely Wednesday, with odds
diminishing Thursday with high pressure building overhead.





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