501
FXUS61 KLWX 011408
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1008 AM EDT Mon Jul 1 2024

.SYNOPSIS...
Behind a cold front, a strong area of high pressure settles
over the area through Tuesday before drifting offshore by
Tuesday night. A warm front nears the region by mid-week
yielding a warming trend. A cold front approaches from the west
late in the week. This system briefs stalls to the west before
lifting northward as a warm front into New England.

&&

.NEAR TERM /THROUGH TONIGHT/...
A thin layer of moisture not resolved well in computer models
has resulted in a transient area of broken to overcast
stratocumulus. These clouds should continue to drift southwest
and scatter out by the afternoon, although there may still be
more clouds around than previously advertised due to cold
advection across the eastern Great Lakes. Wind gusts have also
been notable, with gusts to around 30 mph in some locations.
Some adjustments to dew points have also been made toward lower
guidance due to efficient mixing, ranging from the mid 40s to
mid 50s.

Previous discussion:

The positively-tilted upper trough is slated to exit the Eastern
Seaboard by this afternoon with some gradual building of heights
in the wake. In response to the exiting system, surface
pressures really begin to increase as a 1024-mb ridge tracks
from the Great Lakes toward the northeastern U.S. Relative to
early July climatology, the pressure of this anticyclone will
be around 1.5 to 2 standard deviations above average. Overall,
expect a day with low humidity and high temperatures in the
upper 70s to low 80s (60s in the mountains).

The center of the surface ridge settles over the northeastern
U.S. late tonight into early Tuesday. Mostly clear skies persist
with weakening gradients supporting much less wind. Forecast low
temperatures will be in the 50s for most, with low/mid 60s more
likely along and east of I-95. A few areas of patchy fog cannot
be ruled out in low-lying valley locations.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Throughout the day, the anomalous surface high will slowly push
from interior New England toward the Atlantic coast. As this
occurs, winds begin to shift from northerly to more
east/southeasterly. In response to the wind shift, low-level
moisture will creep up allowing dew points to rise back into the
low 60s for areas east of I-95. Mid/upper heights are expected
to continue increasing as a southern to southeastern U.S. ridge
expands northward. 24-hour mid-level height rises will be on the
order of 6 to 8 dm. Consequently, high temperatures rebound
back into the mid 80s, accompanied by mostly sunny skies. A
light southerly wind should yield a milder night across the
area, particularly west of the Blue Ridge. Low temperatures rise
by about 5 to 8 degrees from the previous night.

Wednesday marks the next possible 90 degree day as heights
further build over the area. The northeastern extent of the
594-dm height line infringes on the I-64 corridor. Its northward
progression generally halts at that point which keeps the Mid-
Atlantic region along a more active portion of the storm track.
This becomes evident as shower and thunderstorm chances return
by late Wednesday into the night. Continued southerly flow
further moistens the lower troposphere as dew points creep back
into the low/mid 60s late in the day. This comes with afternoon
gusts of 15 to 20 mph at times. Nighttime conditions come with
increasing cloud cover and storm chances. Low temperatures
range from the mid 60s to low 70s over the area.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Upper level ridging will be pushing offshore as an upper level
trough tracks eastward across the central Plains to start out the
long term period. At the surface, an area of low pressure located
over the plains looks to track northeast across the Great Lakes and
into Eastern Canada through the weekend. The associated cold front
will stall to our west Thursday and Friday before tracking across
the forecast area on Saturday. This will lead to daily shower and
thunderstorm chances, peaking each afternoon. Sunday will have the
lowest chances of precipitation of the period, with PoPs ranging
from 25-35 percent that afternoon.

High temperatures Thursday through Saturday will be in the upper 80s
to mid 90s with higher elevations staying in the upper 70s to low
80s. High temperatures on Sunday will be a few degrees cooler with
temperatures in the mid 80s to low 90s.

To highlight Independence Day, the aforementioned front will be
located to our northwest providing the area with a chance of showers
and thunderstorms. Showers and thunderstorms are likely for those
west of the Blue Ridge as they are closer to the frontal boundary.
While high temperatures will top out in the mid 90s primarily for
those east of the Blue Ridge, dew points in the mid 70s will lead to
heat indices exceeding 100 degrees for some.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected through mid-week as high pressure
dominates the pattern through late Tuesday. A transient area of
ceilings around FL040 is currently affecting MRB, IAD, and DCA,
but it does appear these should scatter out by afternoon. The
main impacts to the terminals will be the wind shifts. A gusty
northerly wind persists through the late afternoon (with gusts
to 25 kt) to early evening today before weakening after dark.
Light northerly winds give way to an east to southeasterly wind
on Tuesday. As the high fully departs offshore, a return to
southerlies are expected on Wednesday with afternoon gusts to
around 15 to 20 knots. Some late evening/night showers may
approach from the west. However, at this time, these should stay
west of the terminals.

Prevailing VFR conditions are expected at all terminals Thursday and
Friday. Showers and thunderstorms are possible both days at all
terminals with the greatest chances being for KMRB. During any
precipitation, sub-VFR conditions are possible.

&&

.MARINE...
In the wake of a strong cold front, a gusty northerly wind
persists through much of day. Small Craft Advisories are in
place for these gusts which may reach 25 to 30 knots at times.
Winds slowly begin to fall below advisory levels by early in the
evening as a strong ridge approaches from the Great Lakes.
Depending on observational trends, some of the more southern
waters could see a brief extension in such advisories.

Wind gusts remain in the 5 to 10 knot range on Tuesday given
high pressure over the waters. Winds begin to shift to east to
southeasterly as the high slowly drifts toward the New England
coast. By Wednesday, southerlies pick up in earnest which may
lead to some channeling effects. Small Craft Advisories could be
warranted during the afternoon/evening period, especially over
wider portions of the Chesapeake Bay. This may persist into
portions of Wednesday night as well.

Winds stay below SCA criteria both Thursday and Friday across all
waters. Showers and thunderstorms could lead to possible SMWs each
afternoon and into the evening.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will continue to fall through Tuesday with northerly
winds expected. As snapback occurs, a few tidal sites are expected
to hit Action Stage including Baltimore, Annapolis, and Solomons
Island, and Straits Point. No minor flooding is expected at this
time.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ530-
     531-535-536-538-539.
     Small Craft Advisory until 6 PM EDT this evening for
     ANZ532>534-537-540>543.

&&

$$

SYNOPSIS...BRO
NEAR TERM...ADS/BRO
SHORT TERM...BRO
LONG TERM...AVS
AVIATION...ADS/AVS/BRO
MARINE...ADS/AVS/BRO
TIDES/COASTAL FLOODING...AVS