Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
949 am EDT sun Mar 9 2014
high pressure will build over the region today before settling over
the Gulf Coast states Monday and Tuesday. Low pressure and its
associated cold front will pass through later Wednesday into
Thursday. High pressure will return for late in the week.
Near term /through tonight/...
a cold front is located across northern NC this morning while high
pressure continues to move into the region from the west. Northwest flow
around the high will lead to gusty northwest winds today. Overcast
conditions are still apparent on the western slopes of the
Allegheny Front this morning via visible satellite. These clouds are
expected to dissipate by late afternoon. Elsewhere...although
mostly sunny conditions are expected...cold air advection will
lead to a cooler than normal day with temperatures reaching the middle 40s
in northern Maryland to the upper 50s in central Virginia.
the jetstream will be split tonight between a cutoff upper- level
low over Mexico in the southern branch and a fast northwest flow
aloft with several upper-level disturbances in the northern
branch. These upper-level disturbances will remain to our
north...but high clouds will likely increase across our area as
these systems race by. The surface high will also build to our
south tonight...but the gradient should be thin enough...allowing
for the atmosphere to decouple. This means that radiational
cooling will cause chilly conditions. Min temperatures will range from
the middle to upper 20s in the colder valleys and rural areas to the
middle and upper 30s in downtown Washington and Baltimore.
Short term /Monday through Tuesday/...
while another clipper slips by to our north...high pressure hanging
tough over the southeast/southern Atlantic coast will keep pushing warmer air
up the eastern Seaboard. Highs Monday and Tuesday should get above 60 across
much of the region outside of the northern tier of the County Warning Area and higher
terrain. Tuesday will be the warmer day...though an increase in clouds
over the northern half of the area could cap some of the warmer temperatures to
u50s/near 60. The lower Piedmont both Monday and Tuesday will likely top
out in the m60s to near 70. With the tighter pressure gradient from the
clippers passing by to our north...SW winds will strengthen and
usher in this warmer airmass at a faster rate.
Long term /Tuesday night through Saturday/...
still a good amount of discrepancy west/ medium range guidance for the Wednesday
storm system though looking a bit warmer compared to previous runs. One
similarity is the large precipitation shield on the northern side of the surface low
tracks largely north of the County Warning Area...just down into the County Warning Area.
However...the GFS is taking this high gradient precipitation line down
toward the I-66 corridor - roughly bisecting the area. Much of how
this day's weather will play out depends of the exact track of the surface
low...since all guidance has a fairly potent and strengthening surface
feature - wrapping a decent amount of wind and low level shear
around it. Depending how far north/south and intense...it may bring
some elevated or shear-driven convection - espec south and east of
the surface low. Keeping high probability of precipitation west/ a cold rain to start the day but
warming up into the 50s despite the dense cloud cover and steady
Behind this system will be a steady-gradual warm-up into the next
weekend - each day a few degree warmer than the last. High pressure
will make its way over the southeast over the 2-3 day period before
the next longer-term passage of a deep upper trough that will
encompass the East Coast next weekend.
Aviation /14z Sunday through Thursday/...
VFR conditions are expected through tonight. Northwest winds will
gust around 15 to 20 knots today...but winds will diminish and
become light and variable tonight.
High pressure Monday and Tuesday west/ dry conditions and light winds other
than some gusty winds over the mountains on Tuesday. A low pressure system's
passage on Wednesday will bring some precipitation to the area...then move off
the coast by early Thursday.
a Small Craft Advisory is in effect for the waters today. Winds will
diminish late this afternoon and evening as high pressure builds
overhead. A southwest flow will develop late tonight as the high
builds to the south. However...winds should remain below Small Craft Advisory
Light winds from a surface high well to our south to start the week. A
low pressure system will cross the region on Wednesday...bringing a period
Small Craft Advisory gusts behind the system - potentially gale into early Thursday
depending on the track and strength of the low. High pressure will
settle down the area's weather and winds through the end of the week.
District of Columbia...none.
Marine...Small Craft Advisory until 6 PM EDT this evening for