Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
1001 am EDT Wednesday Jun 3 2015
high pressure will reside over the northeast with low pressure
forming off the North Carolina coast. The combination will keep a
cool northeast breeze over the region through Thursday night.
Friday the low will move further out to sea...allowing high
pressure to move into the region for Saturday. The next low
pressure system from the west will move through the region Monday.
Near term /through tonight/...
local area will remain under surface wedge with cloudy and cool
conditions once again. Only weak lift will be available due to
low-level convergence under northeast flow so light rain and
drizzle will be the predominant precipitation modes today. These
conditions will persist through tonight. The most widespread
precipitation will be across the central and southern portions of
the County Warning Area where moisture is a bit deeper.
Maximum temperatures will be well below climatology...ranging from the 50s along
the Allegheny Highlands to the lower and middle 60s across most
other locations. Min temperatures tonight will drop into the 50s for most
Short term /Thursday/...
deeper moisture and stronger lift will overspread the area from
the south on Thursday as closed middle-upper level low over northeast Tennessee
moves east-northeast. This will result in rain becoming heavier especially
over southern Maryland late tonight through Thursday. Model and ensemble quantitative precipitation forecast
averages between quarter inch east of the Blue Ridge to three
quarters of an inch over southern Maryland.
Long term /Thursday night through Tuesday/...
low pressure will form off the NC or Virginia coast by Thursday night. The
gradient between that low offshore and high pressure nosing down
from the northeast states will keep winds gusty on the waters...as
well as clouds and at least a chance of showers and thunderstorms.
Model precipitation has been backing off the past 24 to 48 hours...and
even the 90th percentile of the multi model ensemble has an inch
or less of rain over 24 hours. For all of those reasons will be
removing hazard of potential flooding from our hazardous weather
outlook. While we cant say with certainty some pockets of heavy
rain wont happen with precipitation water around 1.7 inches...the threat
looks isolated at best...with the best chance in southern Maryland where
they can handle more rain.
Past Friday...the forecast gets more uncertain. The most likely
expectation is that high pressure will move more fully over the
region Saturday with not as many clouds...and temperatures reaching
around 80 in the afternoon. Then Sunday...more of the same with
weak low pressure likely forming off NC again with high pressure
nosing down the northeast states. The next frontal system from the
west will move into the region Monday with a 50 to 60 percent
chance of showers or thunderstorms for most.
Aviation /14z Wednesday through Sunday/...
IFR ceilings this morning with ceilings improving to MVFR late this
morning into early this afternoon. Light rain and drizzle is
expected during this time. Deeper moisture and stronger lift will
overspread the area from the south late tonight with model
guidance indicating ceilings dropping to IFR in -ra and visibilities in the
2-4sm range with perhaps some improvement to MVFR during the
daytime hours on Thursday. Would expect MVFR to last through Friday...with a
shift to VFR on Sat. Sunday could be a return to MVFR with surface low
redeveloping off NC and high pressure nosing down from the NE.
a northeast flow will continue through Thursday. A Small Craft
Advisory is in effect for the Maryland Chesapeake Bay and lower
tidal Potomac River during this time. The Small Craft Advisory may
need to be extended into Friday given the slowness of the low
indicated by the ensembles.
District of Columbia...none.
Marine...Small Craft Advisory until 8 PM EDT Thursday for anz530>534-