620
FXUS61 KLWX 030746
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
346 AM EDT Wed Jul 3 2024

.SYNOPSIS...
Surface high pressure will shift offshore throughout the day today,
yielding low humidity and seasonable temperatures. An approaching
frontal system will bring renewed shower and thunderstorm chances
for Thursday and Friday.  The cold front will move over the forecast
area this weekend before stalling over the area allowing
precipitation chances to linger through the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface high pressure will shift offshore throughout the day today,
yielding dry conditions through this evening. A light isolated
shower cannot be ruled out this morning west of the Blue Ridge as a
disturbance moves overhead. Dry air aloft is expected to keep
most precipitation at bay with confidence being too low to
include in the forecast package. After a few days of below
normal temperatures, seasonable temperatures return as southerly
wind and upper level ridging bring in warm and moist air. High
temperatures will be in the upper 80s to low 90s for most with
higher elevations in the low 80s.

As surface high pressure and upper level ridging move offshore, an
approaching cold front will bring increased cloud cover throughout
the day. Thickest cloud cover will be in the northwestern portions
of the area of the forecast area with the front nearby.
Precipitation will return to the forecast overnight with a slight
chance of showers and thunderstorms for those along and west of the
Alleghenies. Overnight low temperatures will be in the upper 60s to
70s for most.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Shower and thunderstorm chances continue to increase throughout
the day as a cold front and a pre-frontal trough approach the
area. Scattered to numerous thunderstorms are expected, peaking
Thursday afternoon as the frontal boundary stalls just west of
the forecast area. CAPE values continue to be favorable for
convection with values ranging from 1500-2500 J/kg. Lapse Rates
and Bulk Shear remain on the weak side with values less than 6
C/km and 30 knots respectively. In addition to convection,
precipitable water values will near record levels with the
latest CAMs agreeing on over 2 inches for those east of the Blue
Ridge. Heavy rainfall and flooding of urban areas will be the
primary threat with thunderstorms on Thursday.

The warming trend continues on Thursday as high temperatures
reach the mid 90s for most. An increase in moisture will result
in heat indices ranging from 94 to 103 degrees at lower
elevations. Overnight low temperatures will be in the 70s for
most.

The cold front will remain stalled just to our northwest on
Friday, allowing continued shower and thunderstorm chances.
Highest chances remain in the western portions of the area
nearest to the frontal boundary. High temperatures will be int
he 90s for most with increased dew points leading to heat
indices reaching triple digits for most at lower elevations.
Overnight low temperatures will provide little relief from the
heat with lows in the mid to upper 70s for those in the I-95
corridor.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
An upper trough digging over the eastern Great Lakes/OH valley
quickly moves northeast and away from the area. In its wake
southwesterly flow prevails aloft through the start of next week,
with several weak shortwaves moving over our area. Unsettled weather
is likely each afternoon/early evening, except for Sunday.

A weak frontal boundary is forecast to be somewhere along or east of
the Blue Ridge Saturday morning. Scattered thunderstorms are
forecast to develop in the afternoon, though most should focus along
and east of the surface frontal boundary. The latest 00Z guidance is
trending drier for the Alleghenies and possibly I-81 corridor, with
most of the rain chances being along/east of US-15. Hot and humid
conditions persist as highs reach the low to mid 90s, with peak heat
indices of 100-105. Given the ample instability and moisture
present, a few strong to severe storms could develop along and east
of the I-95 corridor.

The surface front pushes mostly south of the area Sunday, ushering
in a slightly drier airmass with dew points in the 60s. Highs a tad
bit less hot, in the upper 80s to low 90s. A few showers and
thunderstorms are possible Sunday afternoon, mostly in Central VA
and far southern MD. Otherwise, mostly dry conditions likely.

Unsettled weather returns to the forecast for the start of next week
as deep moisture advects into the region on steady south winds.
Scattered afternoon thunderstorms are forecast each day, with highs
reaching at least the low 90s. Mild overnight lows mostly in the
upper 60s to mid 70s.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
Prevailing VFR conditions are expected today as winds remain out
of the south. Winds pick up this afternoon with MRB, BWI, and
MTN gusting 15-20 knots. Winds are expected to remain light at
all other terminals through tonight with cloud cover
increasing.

Precipitation returns to the forecast Thursday and Friday with
conditions expected to deteriorate to sub-VFR. Reduced CIGs and
VSBYs are likely during any showers and thunderstorms, as well
as gusty winds and frequent lightning. Shower and thunderstorm
chances diminish each night with winds remaining out of the
south/southwest.

Scattered afternoon showers and thunderstorms are possible Saturday
afternoon due to a weak frontal boundary over the area. The highest
chances will be along and east of I-95. Any storm that moves over a
terminal is likely to produce a brief period of sub-VFR conditions,
along with gusty winds. Outside of thunderstorm activity, VFR
conditions are expected.

The front sags south of the area Sunday, bringing mostly dry
conditions. However, a stray afternoon thunderstorm may be
possible.

&&

.MARINE...
A Small Craft Advisory is currently in effect for Wednesday
afternoon and into the evening. Southern channeling will lead
to gusts up to 25 knots over the waters, mainly over the
Chesapeake Bay. Dry conditions are expected throughout today
before precipitation returns to the forecast for Thursday and
Friday. During convection each afternoon, SMWs are likely for
gusty winds.

Scattered afternoon to evening showers and thunderstorms are
forecast Saturday as a weak frontal boundary is draped over the
local waters. Any storm could 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.

Southerly channeling is possible in the open waters of the
Chesapeake Bay Saturday evening to Saturday night. Small Craft
Advisory may be needed for winds gusting to 20 knots for several
hours in the evening.

Winds decrease Saturday night, and remain below SCA criteria Sunday.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies are expected to continue their steady climb through
the rest of this week, into the weekend, and possibly next week as
south to southeast winds prevail for most of the period. Sensitive
locations are expected to reach Action Stage during the higher of
the two daily high tides. Annapolis is the most likely to reach
Minor Flood Stage for the Thursday morning high tide cycle. Beyond
that, will need to continue monitoring trends to see if, and when,
any Coastal Flood Advisories are needed through the weekend.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 5 PM this afternoon to 2 AM EDT
     Thursday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 5 PM this afternoon to 2 AM EDT
     Thursday for ANZ530>534-537>543.
     Small Craft Advisory until 3 AM EDT early this morning for
     ANZ531-532.

&&

$$

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