710
FXUS61 KLWX 021416
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1016 AM EDT Tue Jul 2 2024

.SYNOPSIS...
Dry conditions, seasonable temperatures, and low humidity look to
continue through Wednesday as surface high pressure slowly pushes
offshore. A frontal boundary will approach the area and stall to the
northwest Thursday before crossing the area this weekend. Heat and
humidity will return as a result for the Independence Day holiday
along with increased chances for thunderstorms.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Broad 1027-1028 mb high pressure over Finger Lakes of New York will
continue to wedge it`s way south along the eastern face of the
Appalachians today before shifting toward the New England coast
late tonight and into Wednesday. Dry conditions are expected as
a result along with low humidity and seasonable temperatures.
Highs today will be a touch warmer than Monday with
ridging/rising heights aloft. Highs will range from the mid to
upper 70s over the mountains with mid to upper 80s east of the
Alleghenies. Passing stratocumulus is likely throughout the
afternoon with subtle moisture noted in the low levels between
850-1000 mb per the 12z KIAD sounding (Low Level RH 71% and Mid
Level RH 3%). PWATS are also down around 0.52" signaling the
dry air which is evident across much of the Eastern Seaboard on
the current water vapor imagery.

Winds will turn from the north early this afternoon to the east and
eventually southeast later this evening and into tonight as high
pressure shifts offshore. This will allow for a subtle uptick in
moisture heading into Wednesday. Even with that said, enough dry air
should remain to keep low temperatures in the upper 50s and low to
mid 60s across the region.


Broad high pressure will continue off the New England/Mid-
Atlantic coast Wednesday morning into Wednesday afternoon.
Moist southeast flow off the Atlantic will return as a result
allowing for a subtle boost in humidity across the area. Dry
conditions are expected with mostly sunny to partly cloudy skies
expected. High temperatures Wednesday will run a few degrees
above normal with highs near 90 degrees east of the Alleghenies
(low to mid 80s mountains).

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Wednesday will start out dry with mostly sunny skies. However,
an approaching cold front will bring increased cloud cover and
and a slight chance of showers and thunderstorms to those west
of I-81 Wednesday night into Thursday. Most locations will
remain dry though with increasing mugginess.

Warming trend continues for the 4th of July, as upper level
ridging pivots off the east coast. An approaching frontal
boundary and pre-frontal pressure trough will lead to scattered
to numerous showers and thunderstorms, mainly that afternoon and
into the early evening. High temperatures will soar into the
mid 90s most with heat indices reaching triple digits for some.
Instability increases throughout the day with SBCAPE values
exceeding 1500 J/Kg. However, there still remains a good bit of
uncertainty regarding any convection on Independence day with
weak lapse rates (<6 C/km) and Bulk Shear(<30 knots). Overnight
low temperatures will be in the 70s for most.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The end of this week and start of the weekend look to be active as a
weak surface frontal boundary is stalled over the area. Aloft,
southwesterly flow prevails as the region is in between a slow
moving upper trough over the Great Lakes, and a ridge over the Deep
South. Deep moisture from the Gulf of Mexico works its way north
into our area, bringing PWATs over 2" and dew points in the low to
mid 70s. Scattered to widespread afternoon showers and thunderstorms
are expected each day Friday and Saturday, especially along and east
of the Blue Ridge. A few strong to severe storms are possible given
the ample instability and moisture present. Afternoon highs reach
the low to mid 90s, with peak heat indices between 102-107 east of
the Blue Ridge, and 97-102 west of the Blue Ridge.

The upper trough over the Great Lakes slides northeast as a weak
surface high builds over the OH Valley. The weak frontal boundary
over the area is pushed southward, with drier air moving at least
into the northwestern half of the CWA. A tight moisture gradient is
likely to be present. Isolated to scattered showers/storms focus
mainly in Central VA to southern MD. A slight dip in temperatures to
the upper 80s to low 90s, though less humidity as heat indices
remain below 100 Sunday.

This break in convection/humidity is short lived as the frontal
boundary lifts north over the area as a warm front Monday. Unsettled
weather with scattered afternoon thunderstorms return for the start
of next week.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Prevailing VFR conditions are expected today through Wednesday
night with high pressure in place. Winds remain light and shift
to southeasterly throughout the day today. High level clouds
are expected throughout the day with some low level clouds this
afternoon. Winds remain light and southerly on Wednesday, with
MRB, BWI and MTN seeing the strongest gusts of up to 15 knots.

VFR conditions continue for the most part on Thursday with
southwesterly winds in the morning shifting to westerly in the
afternoon. Scattered to numerous showers and thunderstorms are
expected in the afternoon and could cause conditions to
deteriorate to sub-VFR.

Scattered to widespread showers and thunderstorms are likely across
the area each afternoon Friday and Saturday. Any thunderstorm moving
over a terminal will be capable of producing brief periods of sub-
VFR conditions, in addition to gusty winds and lightning strikes.
Thunderstorm activity could linger into the evening at IAD, DCA,
BWI, and MTN, then clear out overnight. Outside of convection, VFR
conditions are expected.

&&

.MARINE...
Mild and dry conditions are expected across all waters today as
high pressure pivots overhead. Southeasterly winds remain below
SCA criteria through tonight. Winds shift to southerly on
Wednesday with channeling resulting in SCA criteria gusts in the
afternoon and evening.

On Thursday, winds remain out of the south/southeast with SCA
criteria gusts possible in the southern portions of the waters.
SMWs may be needed during showers and thunderstorms that
afternoon.

A weak frontal boundary in place over the local waters will result in
at least scattered thunderstorms each afternoon Friday and Saturday.
These storms will be capable of producing wind gusts in excess of 35
knots and frequent lightning strikes. Special Marine Warnings may be
needed as storms move across the waters. Thunderstorm activity
diminishes in the evening, though a storm or two could last into the
night. Outside of thunderstorm activity, southerly winds around 10-
15 knots are expected.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies are forecast to steadily rise through the week
as southeast to south winds prevail. No coastal flooding
concerns today as most, if not all, sites remain below Action
Stage. However, by Wednesday morning some sensitive locations
will reach Action Stage, and Annapolis is the most likely to go
into minor flooding Wednesday morning. Additional periods of
coastal flooding are possible during the morning high tide
Thursday and Friday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...EST
NEAR TERM...EST
SHORT TERM...AVS
LONG TERM...KRR
AVIATION...AVS/KRR
MARINE...AVS/KRR
TIDES/COASTAL FLOODING...