August 4, 2020
Washington DC Climate Report
Solar Noon: 1:14;
Last 72 Hours: Observations
...THE WASHINGTON NATIONAL DC CLIMATE SUMMARY FOR AUGUST 3 2020...
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
MAXIMUM 87 11:53 AM 101 2006 88 -1 91
MINIMUM 74 3:59 PM 56 1920 71 3 74
AVERAGE 81 79 2 83
TODAY 0.18 1.62 1971 0.11 0.07 T
MONTH TO DATE 0.25 0.32 -0.07 T
SINCE JUN 1 10.27 7.83 2.44 10.76
SINCE JAN 1 27.37 23.79 3.58 28.79
Forecast updates at 6 AM ET
Hazardous Weather Outlook
Flash Flood Watch
Tropical Storm Watch
Hurricane Local Statement
Coastal Flood Watch
Today: Showers and thunderstorms likely, mainly after 4pm. Some of the storms could produce gusty winds and heavy rain. Mostly cloudy, with a high near 88°. Light and variable wind becoming south around 6 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
Tonight: Showers and thunderstorms likely, mainly before 10pm. Some of the storms could produce gusty winds and heavy rain. Cloudy, with a low around 70°. South wind 5 to 7 mph becoming northeast after midnight. Chance of precipitation is 70%. New rainfall amounts between three quarters and one inch possible.
Tuesday: Tropical storm conditions possible. Showers and possibly a thunderstorm. Some of the storms could produce heavy rain. High near 81°. Chance of precipitation is 90%. New rainfall amounts between 3 and 4 inches possible.
Tuesday Night: Showers likely and possibly a thunderstorm before 7pm, then a chance of showers and thunderstorms between 7pm and 1am. Some of the storms could produce heavy rain. Mostly cloudy, with a low around 70°. Southwest wind 5 to 9 mph. Chance of precipitation is 60%. New rainfall amounts between three quarters and one inch possible.
Wednesday: A chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86°. West wind 3 to 6 mph. Chance of precipitation is 30%.
Wednesday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 69°. Chance of precipitation is 40%.
Thursday: A chance of showers, with thunderstorms also possible after 9am. Mostly sunny, with a high near 84°. Chance of precipitation is 40%.
Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70°. Chance of precipitation is 50%.
Friday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 9am. Partly sunny, with a high near 86°. Chance of precipitation is 60%.
Friday Night: Showers likely and possibly a thunderstorm before 9pm. Partly cloudy, with a low around 70°. Chance of precipitation is 60%.
Saturday: A chance of showers and thunderstorms. Mostly sunny, with a high near 88°. Chance of precipitation is 40%.
Saturday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 71°. Chance of precipitation is 40%.
Sunday: A chance of showers. Mostly sunny, with a high near 88°. Chance of precipitation is 30%.
Baltimore/Washington Forecast Office
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Time and Date
Discussion updates at 4 AM ET
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1004 PM EDT Sun Aug 2 2020
Tropical moisture will continue to stream into the region
through Tuesday. Refer to the National Hurricane Center for the
latest regarding the track of Isaias. A weak boundary will
remain near the area for the middle and latter portion of the
.NEAR TERM /THROUGH 6 AM/... An upper level trough to the west
and associated waves of energy pushing into the region this
evening will spawn showers and a few strong thunderstorms across
the southeastern zones of our CWA. The main threat will be
heavy rainfall and perhaps some stronger wind gusts. Localized
flooding cannot be ruled out where showers and thunderstorms
stream across the same zones or individual activity produce
downpours in a short period of time. Tropical moisture will
continue to advect into the area overnight. Additional showers
and storms may develop in any portion of our region. The best
chance for convection will be along and ahead of a surface
trough of low pressure across central and northern Virginia and
toward the I-95 corridor. Localized flooding cannot be ruled
out, but confidence is very low since convection will be
isolated for most areas.
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
With an upper level trough of low pressure to the west and a
constant train of tropical moisture Monday and Monday night,
showers and thunderstorms will be scattered to perhaps
widespread throughout the period. Refer to the National
Hurricane Center for the latest information regarding the track
As the heart of Monday night through the early morning hours of
Tuesday roll around, the possibility of minor to moderate
flooding lurks in the eastern half of our region. This is also
about the time that Isaias will be moving through the Carolinas
and approaching southeast Virginia. Locally heavy rainfall is
highly possible along with the potential for flash flooding.
Also, a few severe storms cannot be ruled out due to increased
mid and upper-level flow from the trough nearby. Damaging winds
appear to be the primary threat from any severe storms that
develop, and the best chance for severe storms may be around
peak heating of Monday afternoon and evening.
Isaias is most likely to pass through or nearby the area Tuesday
into Tuesday night. Heavy rainfall expected and flash flooding
is possible with the passage of this system. Confidence for the
heavy rainfall is highest along and east of the Blue Ridge
Mountains. Tropical storm force winds may impact portions of
the area. Therefore, it is important to monitor the National
Hurricane Center for the latest information for the latest
information on Isaias. The best chance for tropical storm force
winds will be near and east of the center of Isaias, but the
heavy rainfall may extend well north and west from the track of
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The upper level trough that will have been steering Isaias to
the NE will begin to lift to the north Wednesday allowing high
pressure to be positioned near the Ohio Valley. Frontal boundary
to our SE will linger and bring chances for showers and storms
across our CWA Wednesday. Shortwave energy will persist
throughout the workweek bringing daily chances for showers and
storms to fire off during diurnal heating periods. Most model
guidance (GFS, ECMWF, Canadian) is confident on the periods of
showers and storms but timing and intensity is still more
sporadic in nature at this time with regards to confidence. The
upper level trough looks to drive a departure from these periods
of rain with the upper trough axis allowing for the frontal
boundary plaguing our area for the days prior to finally move
through our area Friday and bring drier conditions for the
Temperatures for the extended period look to be at or just
below normal for this time of year with highs struggling to
reach 90F. Lows look to dip down in the 60s to potentially a few
places reaching the 50s across some of our western zones.
Frontal boundary will bring some drier, less humid conditions
for the end of the work.
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