Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
310 PM EST Friday Mar 7 2014
low pressure just off the North Carolina coast this afternoon will
move out to sea tonight. High pressure briefly returns tonight and
Saturday before a cold front moves through Saturday night. High
pressure will build overhead early next week.
Near term /through Saturday/...
lopres is located about 50 miles south of Cape Hatteras. This low
will continue to strengthen as it moves pulls away from the NC coast
tonight. There has been little northward progression of the precipitation shield
this afternoon as the upper low moves more W-E...keeping synoptic lift
generally south of the area. Northwestern fringe of very light rain will exit
central Virginia within the next hour or so. Precipitation will take longer to
pivot through southern Maryland...and may linger through 00z or so. The cities and
its western suburbs will remain dry.
Broad area of hipres settles into the region tonight in wake of the
coastal low. The clearing skies this afternoon will continue from west to
east this evening. Min temperatures range from the middle 20s near the Mason-Dixon
line and Allegheny Front to around 30 in the cities and along the
Weak hipres will shift south of the area as a cold front approaches
from the Ohio Valley. Pre-frontal westerly/downsloping flow off the
Appalachians will yield a mild day with temperatures above normal. Maximum
temperatures generally in the 50s...and even low 60s in central Virginia.
Short term /Saturday night through Monday/...
clouds will increase from the north Saturday evening as a cold front
moves south from the Great Lakes region. Deterministic models over
the past few days have shown weak forcing and lack of moisture with
this front. The latest 12z runs continue this trend. A wind shift to
the northwest will aide in upslope snow development on the western slopes
of the Allegheny Front. Little to no accumulation is expected.
Elsewhere...only a few hundredths of an inch are expected as the
front moves across the middle Atlantic into Sunday morning leading to
light rain showers. Temperatures will drop the low to middle 30s by Sun
morning so snow may mix into the back edge. Clouds will exit southern
Maryland/northern Piedmont by late morning Sunday and mostly clear conditions
are expected. Winds will veer out of the northwest and temperatures will rise into
the 40s and 50s Sunday. Mostly clear conditions Sun night will allow
temperatures to drop into the low 30s by Monday morning.
High pressure moves into the region Sunday and Monday. Temperatures are
expected to reach the upper 50s and low 60s Monday.
Long term /Monday night through Friday/...
southwesterly flow in the wake of departing high pressure will bring
a continuation of above normal temperatures Monday night into
Tuesday...with highs similar to those forecast for Monday. Clouds
will increase from west to east Tuesday afternoon ahead of an
approaching upper trough.
The upper trough will spawn a surface low that will track west to
east near or over the area during the middle of next week. Depending
on the exact track of the storm and the amount of available cold air
in place...some parts of the area could receive another round of
wintry precipitation. At this time it appears the most likely areas
to see wintry weather would be confined well north and west of the
I-95 corridor...but large ensemble model spread lends to uncertain
forecast details during this time.
Of greater certainty is yet another shot of well below normal
temperatures which will follow on the heels of the midweek system.
These colder temperatures /I.E. Highs in the upper 30s-lower 40s and
lows in the 20s/ will persist through the end of next week. This is
about 10 degrees below normal for this time of year.
Aviation /20z Friday through Wednesday/...
VFR conditions this afternoon and evening under clearing skies and northerly winds
5-10 knots. Patchy fog may develop late tonight under a good radiational
cooling setup...but confidence in this happening is too low to
include it tafs. There is perhaps a better chance for fog
development at cho where light precipitation fell this morning. VFR on Sat with
westerly winds 5-10 knots.
A cold front will cross the region Sat night/Sun morning. Light rain or
snow showers are expected. No restrictions expected at this time.
Sub-VFR conditions are likely in rain or possible mixed
precipitation during the middle of next week. Northeast winds at or
below 10 knots Tuesday become northwest by Thursday.
made some headline changes with the Small Craft Advisory for the remainder of the
afternoon and tonight...removing the upper tidal Potomac and northern most Bay
zone. After 06z...Small Craft Advisory only in effect for the lower tidal Potomac and
approx southern half of the Maryland chesepeake Bay. Winds below Small Craft Advisory on Sat.
A cold front will cross the waters Sunday morning and winds will
increase out of the northwest by Sunday afternoon. Winds capped to just
below Small Craft Advisory.
Sub-Small Craft Advisory conditions are forecast during the middle of next week in
light flow below 10 knots as low pressure moves near or over the
District of Columbia...none.
Marine...Small Craft Advisory until 1 am EST Saturday for anz531-536-
Small Craft Advisory until 6 am EST Saturday for anz532>534-