November 28, 2020
Washington DC Climate Report
Solar Noon: 11:56;
Last 72 Hours: Observations
...THE WASHINGTON NATIONAL DC CLIMATE SUMMARY FOR NOVEMBER 27 2020...
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
MAXIMUM 61 3:46 PM 75 1896 53 8 58
MINIMUM 51 11:45 PM 14 1938 38 13 44
AVERAGE 56 46 10 51
YESTERDAY 0.00 1.82 1944 0.11 -0.11 0.01
MONTH TO DATE 3.75 2.85 0.90 1.37
SINCE SEP 1 14.14 9.97 4.17 8.28
SINCE JAN 1 49.99 36.37 13.62 39.06
Forecast updates at 6 AM ET
Today: Scattered sprinkles between 2pm and 5pm. Mostly cloudy, with a high near 61°. Light north wind.
Tonight: Scattered sprinkles after 8pm. Mostly cloudy, with a low around 43°. Light and variable wind.
Saturday: Mostly sunny, with a high near 59°. Light northwest wind increasing to 5 to 10 mph in the morning. Winds could gust as high as 21 mph.
Saturday Night: Mostly clear, with a low around 35°. Northwest wind 3 to 6 mph.
Sunday: Sunny, with a high near 57°. Light and variable wind becoming south around 6 mph in the afternoon.
Sunday Night: Rain, mainly after 2am. Low around 43°. Chance of precipitation is 90%.
Monday: Rain before 8am, then showers after 8am. High near 62°. Chance of precipitation is 100%.
Monday Night: Showers before 8pm. Low around 40°. Chance of precipitation is 100%.
Tuesday: Partly sunny, with a high near 47°.
Tuesday Night: Partly cloudy, with a low around 31°.
Wednesday: Mostly sunny, with a high near 45°.
Wednesday Night: Mostly clear, with a low around 31°.
Thursday: Mostly sunny, with a high near 48°.
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Time and Date
Discussion updates at 4 AM ET
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
834 PM EST Thu Nov 26 2020
Surface high pressure will build overhead through Friday.
A weak cold front will pass through Friday night, followed by
high pressure for the weekend. Next up is a strong storm system
moving up from the Deep South. That is expected to move
northeast through the Mid Atlantic on Monday. That storm will
stall over Ontario and remain there to our north through
.NEAR TERM /THROUGH FRIDAY/...
Surface high pressure will build overhead overnight through
Friday, bringing dry conditions for most areas. Temperatures
will be cooler than previous days, but still above normal for
this time of year.
A weak upper-level disturbance will pass through the region late
tonight through midday Friday, and this will back the low-level
flow a bit to be south of west. Despite limited moisture there
should be enough overrunning for a bkn/ovc stratus deck along
with a possible sprinkle.
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Another cold front moves east across the region Friday night.
The only precipitation possible appears to be in Garrett Co MD
and adjacent highlands, and that threat is from light showers or
drizzle late Fri night into Sat morning. At this point, kept
that liquid. But temps get close to freezing late Fri night
there. So the threat of some freezing drizzle will need to be
monitored. The moisture is mainly in the low levels, so any
rainfall amount would be very small.
Otherwise, fair weather again Saturday into Sat night with
temps slightly cooler again, but near or a little above normal.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Surface high pressure will make its way from the Ohio Valley through
the Mid-Atlantic region on Sunday, leading to clear skies and dry
conditions to finish out the day. Digging trough just west of the
Great Lakes will move in along with a cutoff low by late Sunday
night. Most models have precip reaching central VA by 9z Monday
morning. Agreement on the center of the low pressure by 6z Sunday
night is starting to come to terms with around the Tennessee Valley.
After that is where confidence becomes low again with respect to
positioning of the cutoff. Nonetheless, a surge of moisture will be
coming up from the south Monday. This will lead to a mostly wet day
with some brief heavy rain potential given the environmental
setup. GEFS members averaging around 1.15" PWATs for the day on
Monday. There is a chance a line of convective showers or
thunderstorms could form Monday. Main concern for this would be
brief damaging wind gusts with the storms given the chance for
strengthening low and mid-level wind fields. The wind potential
is likely there if there can be enough instability to form
storms, which is questionable right now. Many model ensemble
members have instability, many do not.
The heaviest batch of moisture should exit the area by late Monday
night. The upper level low appears to close off or come pretty close
to doing so. This, along with the positioning of the shortwave and
location relative to our CWA will dictate further impacts on the
backside of this system. Most models are in agreement with the
chance for upslope snow along and west of the Allegheny Front from
Monday night through early in the day on Wednesday. The interactions
between the cutoff low, the digging trough and the shortwave will
heavily dictate the impacts we may see. This will be an evolving
forecast over the next few days with regards to timing, impacts and
locations of the system.
Temperatures for the extended will start off in the low to mid 50s
across most areas Sunday before warming up a bit (given the warm
moist air associated with the cutoff) to near 60F. Most models are
in agreement of a blast of cold air intruding behind the system
Monday night into Tuesday. Temperatures along and west of the
Allegheny Front could be below freezing for 24+ hours Monday night
into Tuesday night/Wednesday. A system this complex deserves a close
eye as we get closer to the time frame.
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