Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
908 PM EDT Thursday may 23 2013
Synopsis...
a cold front will cross the middle-Atlantic region tonight. An upper
level low will reside over the area on Friday...then Canadian high
pressure will build overhead for the Memorial Day weekend. A warm
front will pass through the area during the early to middle
portion of next week.
&&
Near term /through Friday/...
cold front in/near the shen valley at this time. After an afternoon where storms were
scattered and lacked organization...finally have a concentrated structure
to work off of. However...W/ loss of diurnal heating we/re losing
what severity we had. Central Virginia has been largely untapped...and
expect thunderstorms and rain to have more life there. Elsewhere...the heavy rafl will be the
bigger impact. Lwx radiosonde observation demonstrates this premise...W/ more cinh
than cape and 1.33 inch precipitable water. Will keep probability of precipitation high until frontal passage...then
scale back. Wind shift to the northwest occurs behind the front
overnight...and dewpoints will begin to decrease with cooler air
moving in for Friday.
Friday will certainly feel like a different day with maxima
reluctant to rise much during the day with low level cold
advection at play and an upper low overhead. Maxima in the lower
to middle 60s can be expected. Decent gradient with cold advection
will bring a windy day...with gusts possibly over 35 miles per hour at times.
With the upper low overhead expect plenty of clouds and also
scattered showers particularly across the northern portion of the
County Warning Area. Showers may produce stronger wind gusts and also can/T rule
out some small hail due to cold air aloft.
&&
Short term /Friday night through Sunday/...
upper low drifts to the northeast on Saturday...as high pressure
builds in for the rest of the weekend. It looks like winds stay up
Friday night...so no frost is expected. But temperatures could
drop close to freezing over The Highlands late Friday night.
Another windy and cool day is expected on Saturday although some
sunshine should make a return. Moderating temperatures and
sunshine are expected Sunday.
&&
Long term /Sunday night through Thursday/...
500 mb rises through entire long term as Bermuda high starts setting up
at the beginning of the period with warm front passage likely on
Tuesday per 12z GFS. Monday appears stable with little or no model
cape. On Tuesday...instability starts to work into the shen valley
with Wednesday and Thursday having moderate instability across
entire County Warning Area.
Maximum temperatures Monday and Tuesday are around climatology...then increasing up
to 10 degree above climatology with maximum temperatures approaching 90 Wednesday and
Thursday.
&&
Aviation /01z Friday through Tuesday/...
rain showers/thunderstorms and rain in metropolitan balt and down the shen valley. Flgt restrictions
at this time gnly MVFR...although could have local IFR west/in shra/tsra. There may be
a few rain showers thereafter...as well as occasional MVFR ceilings. Could be
contending west/ a little fog as well until frontal passage.
A cold front moves through the area overnight with a wind shift.
Cooler/drier air will take care of any residual fog. Expect gusty
northwest winds on Friday...with scattered showers that may
produce gustier winds.
Strong northwesterly flow continues through Saturday as the upper low
remains in the region and surface high pressure builds. VFR early next
week in a Canadian airmass before a midweek warm front.
&&
Marine...
aside from drum pt-Smith pt and adjacent Tangier Sound...winds hvnt
really been reaching Small Craft Advisory crit. Even in the Middle Bay...spds starting
to subside. Will allow Small Craft Advisory to expire at 10 PM. That/S not to say
there wont be gusty winds...but they will be associated west/ rain showers and thunderstorms and rain
crossing along and ahead of cold front. Anticipate special marine
warnings will be reqd overnight.
Cold front moves through overnight with winds shifting
to the northwest. These winds will be gusty on Friday...for a
solid Small Craft Advisory. May even flirt with gales due to
gradient effects alone. In addition...scattered showers may
produce stronger wind gusts.
Northwesterly flow with gusts 25 to 30 knots through Saturday as an upper low
persist over the region and surface high pressure builds. More
tranquil weather early next week under a Canadian airmass.
&&
Tides/coastal flooding...
anomalies running 1/2 feet above normal tonight. No coastal Flood
Advisory is expected. Winds will shift to the northwest overnight
into Friday behind a cold front...bringing a return to normal at a
minimum...and more likely blow out conds.
&&
Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...none.
Virginia...none.
WV...none.
Marine...Small Craft Advisory until 10 PM EDT this evening for
anz531>534-537>543.
Small Craft Advisory from 6 am Friday to 6 am EDT Saturday for
anz530>543.
&&
$$
Synopsis...bpp
near term...hts/bpp
short term...bpp
long term...Lee
aviation...hts/bpp/baj
marine...hts/bpp/baj
tides/coastal flooding...heights
