TTCM () > WeatherWednesday, August 10, 2022 — W1 W2 93% W4 W5 91°F
Washington DC Climate ReportDeckSunrise: 6:18 (W1: 26%); Solar Noon: 1:13 (W3: 57%); Sunset: 8:09 (W5: 88%)

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Last 72 Hours: ObservationsCurrently: 91°F  — USNO Clear Sky ChartHeavens-Above

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                VALUE   (LST)  VALUE       VALUE  FROM      YEAR
  MAXIMUM         97   2:00 PM 102    1930  89      8       92
  MINIMUM         77   5:11 AM  57    1989  72      5       73
  AVERAGE         87                        80      7       83

  TODAY            0.00          2.71 1905   0.11  -0.11     0.00
  MONTH TO DATE    1.44                      1.00   0.44     0.59
  SINCE JUN 1     12.01                      9.53   2.48    10.34
  SINCE JAN 1     30.97                     25.66   5.31    26.70

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Flood Watch
Hazardous Weather Outlook

Today: Scattered showers and thunderstorms after 3pm. Some of the storms could produce gusty winds and heavy rain. Mostly sunny, with a high near 92°. Heat index values as high as 101. Light north wind. Chance of precipitation is 30%.

Tonight: Showers and possibly a thunderstorm before 9pm, then showers and thunderstorms likely, mainly between 9pm and midnight. Some of the storms could produce gusty winds and heavy rain. Low around 71°. Light and variable wind. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.

Thursday: A chance of showers and thunderstorms before noon, then a slight chance of showers between noon and 3pm. Partly sunny, with a high near 86°. Northwest wind 3 to 6 mph. Chance of precipitation is 40%.

Thursday Night: Partly cloudy, with a low around 68°. Northwest wind 3 to 6 mph.

Friday: Sunny, with a high near 82°. North wind 6 to 9 mph.

Friday Night: Mostly clear, with a low around 62°.

Saturday: Sunny, with a high near 82°.

Saturday Night: Mostly clear, with a low around 62°.

Sunday: Mostly sunny, with a high near 84°.

Sunday Night: Partly cloudy, with a low around 67°.

Monday: Partly sunny, with a high near 82°.

Monday Night: Mostly cloudy, with a low around 66°.

Tuesday: A chance of showers. Partly sunny, with a high near 83°. Chance of precipitation is 40%.

Baltimore/Washington Forecast Office

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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
355 AM EDT Wed Aug 10 2022

A cold front will approach today before passing through tonight
into Thursday before a reinforcing cold front passes through
Thursday night. Canadian high pressure will build overhead for
the weekend. The high will move offshore early next week while
an upper-level trough remains overhead.

Warm and humid conditions are expected through early this
morning along with patchy fog. However, fog should not be
widespread due to some clouds and weak dry air advection in
northern areas.

For the rest of today, a weak cold front will most likely stall
to our north, but a surface trough has moved into the region and
this will most likely stall out overhead this afternoon into
this evening. There will not be much of a temperature gradient
with the trough, and with the weak cold front to our north this
will allow for another very warm and humid day. Highs will range
from the mid to upper 80s in northern MD into the Shenandoah
Valley to the lower 90s around Washington DC into central
Virginia and southern MD. It will not be quite as hot as
Tuesday, but still quite warm and humid.

The heat and humidity will once again lead to moderate and even
high amounts of CAPE and the surface trough along with terrain
circulation will act as lifting mechanisms for showers and
numerous thunderstorms to develop. Despite weak shear, steep
low-level lapse rates and higher DCAPE suggests that some storms
will be capable of producing damaging wind gusts. However,
there is also a threat for flash flooding. Storm motion will be
slow, combined with higher CAPE, a surface boundary, and low MBE
vectors suggesting that the steering flow is weak and nearly
parallel to that boundary. Therefore, training storms and slow
moving storms pose a threat for flash flooding. A Flash Flood
Watch has been issued for the Washington and Baltimore Metro
areas into northern and central Virginia as well as central and
southern Maryland, and also into portions of the Potomac
Highlands. This is where instability is likely to be highest
near and south of the surface trough. Localized rainfall amounts
around 2 to 4 inches are possible in a short period of time
(about 1 to 2 hours). Farther north and west across the northern
Shenandoah Valley into northern MD and the Allegheny Highlands,
some dry air advection may limit instability a bit, decreasing
confidence a bit for heavy rainfall. However, it certainly is
not out of the question that the flash flood watch may need to
be extended a bit farther north and west later today, especially
if the surface trough sets up just a bit farther north (which
some guidance does show).

Convection should diminish somewhat in coverage later this
evening with the loss of daytime heating, but the cold front
will be dropping through overnight while an upper-level
disturbance passes through the area. Therefore, at least chances
for showers and thunderstorms will persist into the overnight
hours. Lows tonight will be in the 60s and 70s.

The cold front will likely get hung up over central Virginia and
southern Maryland Thursday while a reinforcing cold front
approaches from the northwest. A few morning showers are
possible, but drier air in between these two boundaries should
bring dry conditions for much of the time Thursday. The one
exception will be across central Virginia into extreme southern
MD where showers and thunderstorms are possible closer to the
cold front. Another exception may be over northern MD into
eastern WV and the Allegheny Highlands later Thursday afternoon
into Thursday evening where a couple popup showers and
thunderstorms are possible ahead of the reinforcing cold front.

The reinforcing cold front should pass through Thursday night
and Canadian high pressure will build in behind the cold front
for Friday through Friday night. Noticeably cooler and much less
humid conditions are expected behind the cold front for Friday
and Friday night. Highs Friday will most likely be in the 70s to
lower 80s, and lows Friday night will be in the 40s for some of
the colder valleys and Allegheny Highlands, with 50s to lower
60s most likely elsewhere.

By the early part of the weekend, an upper trough will continue to
linger across the northeast and Mid-Atlantic states through early
next week. Surface high pressure will likely influence the area
through the weekend with temperatures near or slightly below normal
and lower humidity values. The high will begin to shift towards the
east by late Sunday night and will likely increase humidity and
moisture availability by early next work week. By the beginning of
next week, increasing instability and abundant moisture may allow
for increase risk for showers and thunderstorms for each afternoon
and evening. Temperatures will continue to meander back to normal
values for this time of year by midweek next week.

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