Flash Flood Warning 63, NWS Baltimore/Washington

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
312 PM EDT Tue Jul 1 2025

.SYNOPSIS...

An upper trough and associated cold front will move through the
area later tonight into tomorrow. High pressure will build over
the area later this week into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...

Multiple lines of showers and thundestorms are currently ongoing
at this time. Radar trends and simulated satellite imagery from
various models indicate lines may merge across central and
northeast MD posing a significant flash flooding threat into the
evening. New 12Z ECMWF AIFS Ensembles and its ensemble mean
show potential for significant rainfall totals along the US-29
corridor and I-95 from Washington DC to Wilmington DE. Severe
threat should start diminishing after 00Z, but flooding may
still be ongoing after 00Z. Peak rainfall rates should start
diminishing after 00Z tonight as instability is exhausted, but
light rain will continue well through the night on the cool
side of the sfc boundary. A rainy night is expected for most
tonight.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...

Showers are still likely to be ongoing south of I-70 at 12Z Wed,
but should start progressing southward more rapidly through the
day and should have mostly exited the fcst area by 18Z, except
perhaps the southern tip of St. Mary's County. After that, dry
air will filter in.

A reinforcing shortwave-trough will move across the area Thu
afternoon bringing a threat of showers or thunderstorms across
areas west of I-81. Dry Thu night into Fri just in time for the
Fourth of July.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...

Dry conditions and seasonable temperatures continue Friday
through Sunday. Heat and humidity returns Sunday night and
Monday and so does the shower and thunderstorm chances through
this period. A trough of low pressure will be the focal point of
any convection Sunday night and Monday morning. A cold front
that follows the trough will be the focal point of convection
Monday afternoon and evening. Highs Friday through Sunday will
be in the middle to upper 80s. Highs Monday should reach near 90
or the lower 90s.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...

Widespread thunderstorms expected through 01Z, but showers could linger
well into the overnight. Brief IFR/LIFR conditions are likely. Windshift
is not expected until after 00Z.

VFR conditions at all terminals Friday through Saturday night. Winds
northwest around 5 knots becoming light and variable Friday into
Friday night. Winds light becoming southeast 5 knots Saturday and
Saturday night.

&&

.MARINE...

SCA conditions are possible across the middle and lower bay and
south of Cobb Island. In addition, numerous thunderstorms are
expected which may produce strong wind gusts in excess of 34 kt.
SMWs may be required. Winds are expected to diminish Wed
morning.

No marine hazards Friday through Saturday night. Winds northwest 5
to 10 knots Friday and Friday night. Winds becoming southeast 5 to
10 knots Saturday and Saturday night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flood Watch until 11 PM EDT this evening for DCZ001.
MD...Flood Watch until 11 PM EDT this evening for MDZ003>006-008-
     011-013-014-503>508.
VA...Flood Watch until 11 PM EDT this evening for VAZ026>031-
     038>040-051-053-054-501-502-505>507-526-527.
WV...Flood Watch until 11 PM EDT this evening for WVZ050>053-055.
MARINE...Flood Watch until 11 PM EDT this evening for ANZ530.
     Small Craft Advisory until 9 PM EDT this evening for ANZ532-
     533-540>542.
     Small Craft Advisory until 6 AM EDT Wednesday for ANZ534-537-
     543.

&&

SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...KLW
AVIATION...LFR/KLW
MARINE...LFR/KLW

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
103 PM EDT Tue Jul 1 2025

ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508-
VAZ053>057-527-021000-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Cecil-Southern Baltimore-
Prince Georges-Anne Arundel-Charles-St. Marys-Calvert-
Central and Southeast Montgomery-Central and Southeast Howard-
Southeast Harford-Fairfax-Arlington/Falls Church/Alexandria-
Stafford-Spotsylvania-King George-
Central and Southeast Prince William/Manassas/Manassas Park-
103 PM EDT Tue Jul 1 2025

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and I-95 corridor through
central Maryland, northern Virginia, and District of Columbia.

.DAY ONE...This Afternoon and Tonight

A Flood Watch for flash flooding is in effect from Prince
William/Prince Georges/Anne Arundel County northward from 2 PM
until 11 PM today. Elsewhere, isolated instances of flash flooding
may be possible this afternoon into this evening.

A Severe Thunderstorm Watch is in effect until 9 PM tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Skywarn Spotter activation is needed.

MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508-
526-WVZ050>053-055-021000-
Washington-Frederick MD-Carroll-Northern Baltimore-
Northwest Montgomery-Northwest Howard-Northwest Harford-Augusta-
Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-Nelson-
Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper-
Northern Fauquier-Southern Fauquier-Western Loudoun-
Eastern Loudoun-Northern Virginia Blue Ridge-
Central Virginia Blue Ridge-Northwest Prince William-Hampshire-
Morgan-Berkeley-Jefferson-Hardy-
103 PM EDT Tue Jul 1 2025

This Hazardous Weather Outlook is for portions of eastern West
Virginia, northern and central Virginia, and central and western
Maryland.

.DAY ONE...This Afternoon and Tonight

A Flood Watch for flash flooding is in effect from 2 PM to 11 PM
from Rockingham/Greene/Madison/Culpeper Counties northward.
Elsewhere, isolated instances of flash flooding may be possible
this afternoon into this evening.

A Severe Thunderstorm Watch is in effect until 9 PM tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is needed.

MDZ501-502-509-510-VAZ503-504-WVZ501>506-021000-
Extreme Western Allegany-Central and Eastern Allegany-
Western Garrett-Eastern Garrett-Western Highland-Eastern Highland-
Western Grant-Eastern Grant-Western Mineral-Eastern Mineral-
Western Pendleton-Eastern Pendleton-
103 PM EDT Tue Jul 1 2025

This Hazardous Weather Outlook is for the Allegheny Front
counties in western Maryland, eastern West Virginia, and Highland
County Virginia.

.DAY ONE...This Afternoon and Tonight

Isolated instances of both damaging winds and flash flooding may
be possible in association with thunderstorms this afternoon into
this evening.

A Severe Thunderstorm Watch is in effect until 9 PM tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is needed.

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