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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 141427 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
1027 AM EDT Sun Apr 14 2024

.SYNOPSIS...
Low pressure will track to our north today, and eventually drag
a cold front southward across the area later tonight into the
day tomorrow. This front will return northward as a warm front
during the day Wednesday. A cold front will move through the
area late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

-- Changed Discussion --
Big rebound in temperatures is expected today with temperatures
expected to approach 80 under gusty SW winds. Recent NBM trends
suggest temperatures could get as high as low 80s. Hi-res models
indicate enough instability to produce some weak pop-up showers
west of I-81 this afternoon well ahead of tstm activity dropping
southward from PA tonight. Expect an increase in high level
clouds this afternoon, othwerwise dry.

Previous afd...

A weak mid- level disturbance and associated surface low will
track from the Great Lakes toward upstate NY today.
Thunderstorms are expected to develop this afternoon in the
vicinity of the system`s cold front, which will stretch from
upstate NY into northern PA and OH. This activity should remain
to our north during the daylight hours, with mostly sunny skies
forecast locally. High temperatures are expected to reach into
the upper 70s to lower 80s for most. Winds will pick up out of
the southwest this afternoon, with gusts of 25-35 mph possible
during the late afternoon hours.

The aforementioned thunderstorms will drop southward toward the
area tonight, reaching northern Maryland and portions of the WV
Panhandle during the mid-late evening hours. The trend should be
for these storms to weaken as they move into the area, but an
instance or two of damaging winds or large hail may be possible
across western MD or the WV Panhandle before the storms weaken
further. Locations to the north of I-66/US-50 could experience a
brief shower or storm during the first half of the night before
storms totally decay. Temperatures will drop back into the
upper 50s to near 60 overnight.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A cold front will continue to slowly drift southward across the
forecast area during the day tomorrow. Much of the area should
remain dry, but a few thunderstorms may form on the warm side of
the boundary from central Virginia to southern Maryland during
the afternoon hours. Model soundings show around 1000-1500 J/kg
of surface based CAPE, with around 35-40 knots of shear in a
straight hodograph (westerly flow through the column). Both
low and mid-level lapse rates are steep, with the mid-level
lapse rates uncommonly steep at around 8 degrees C/km.
Multicells or a marginal supercell may be capable of producing
damaging winds or severe hail in such an environment. SPC
currently has far southern portions of the forecast area
outlooked in a Marginal risk. Further north, mostly sunny skies
are expected. It will be a warm day for all, with highs
generally in the mid 70s to lower 80s (60s mountains).

A closed upper low will track eastward onto the Central Plains
on Tuesday. A weak band of warm advection aloft well in advance
of the system may potentially lead to the development of a few
showers or a thunderstorm Tuesday afternoon well in advance of
the system across central Virginia, the Shenandoah Valley, or
the mountains. This slight chance for a storm will spread
northeastward overnight. However, most locations should remain
dry. Temperatures on Tuesday will be a few degrees cooler, but
still above normal for mid-April, with highs generally in the
70s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As one expansive upper trough exits into the Canadian Maritimes,
additional shortwave energy pushes across the Ohio Valley late
Wednesday. Height falls associated with this system largely stay
confined to areas north of the Mid-Atlantic region. A brief period
of height rises ensues on Thursday ahead of a more potent upper
trough extending from southern Ontario back toward the Canadian
Rockies. 500-mb height anomalies run between 1 to 1.5 standard
deviations below average per numerous global ensemble systems.
Although the core of lower heights should straddle the international
border with Canada, the resultant cold frontal passage will favor a
pattern shift into next weekend. Before this occurs, expect a warm
and occasionally humid air mass to rule the forecast period. This
will introduce nearly daily risks for showers and thunderstorms.

Looking more closely at the pattern, a warm front tracks across the
Mid-Atlantic region on Wednesday. This leads to a southerly surge of
moister air as dew points rises into the upper 50s to low 60s. The
combination of increasing warmth and instability with weak forcing
from a passing trough should enhance rain shower chances.
Additionally, there will be a slight chance of thunderstorms,
particularly during the afternoon to evening hours. Overall buoyancy
profiles do not look terribly impressive, but imagine the threat
will be better ironed out once into the high-resolution model
timeframes. A rather diffuse cold front pushes across the area early
Thursday before a stronger system enters the picture by Friday. This
latter push also brings another chance for thunderstorms given
stronger upward forcing along the cold front. Some shower chances
linger into the weekend as troughing remains overhead.

The overall temperature forecast favors above average readings
through Friday. Daily highs will rise into the 70s each day,
accompanied by mild overnight conditions. Expect a gradual downtick
by late in the work week before a more pronounced drop off is noted
by next weekend. At this point, highs in the upper 50s to 60s become
more commonplace, locally cooler in the mountains. During this
mid/late week period, expect breezy afternoon conditions given deep
mixed boundary layers. Winds shift over to northwesterly over the
weekend as cold advection persists.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected at the terminals through Tuesday. A
few residual showers could impact the terminals overnight
tonight, but chances are too low to mention in the TAFs at the
moment. Winds today will turn southwesterly and gust to around
20-30 knots during the afternoon hours. Winds will turn out of
the northwest tomorrow, and then south on Tuesday.

With a warm front pushing through the area on Wednesday, winds shift
from southeast to southerly. Afternoon gusts could approach 20 to 25
knots at the area terminals. This is accompanied by a threat for
showers and some thunderstorms. Periods of sub-VFR conditions are
possible in this regime. A weak cold front tracks through early
Thursday which shifts winds over to northwesterly before turning
more north-northeasterly later in the day. Shower chances persist
but convection appears less likely. Additional restrictions are
possible due to the rain shower threat.

&&

.MARINE...
Winds will pick up out of the southwest today. Warm air moving
over cooler waters will keep wind speeds lower over water than
on land, but Small Craft Advisory conditions are still expected
this afternoon into this evening. Sub-SCA northwesterly winds
are expected tomorrow, with winds eventually turning light out
of the south by Tuesday afternoon.

A shift to southerly winds with the warm front will lead a gusty
wind which overspreads the area waterways. Small Craft Advisories
may be needed Wednesday afternoon into portions of the night as
gusts rise into the 20 to 25 knot level. Additionally, there will be
a threat for showers and some thunderstorms. The latter may
necessitate Special Marine Warnings for the stronger cores. A weak
cold front moves through Thursday morning leading to north-
northeasterly winds. Winds near advisory thresholds at times on
Thursday.

&&

.FIRE WEATHER...
Winds will pick up this afternoon out of the southwest, reaching
around 15-20 mph sustained, with gusts to around 25-35 mph
during the late afternoon hours. Minimum relative humidity
values should be around 30-40 percent to the north and west of
I-95, and between 25 and 30 percent to the south and east of
I-95.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 1 AM EDT Monday for ANZ530>532-535-
     536-538>540.
     Small Craft Advisory until 5 AM EDT Monday for ANZ533-534-537-
     541>543.
-- End Changed Discussion --

&&

$$

SYNOPSIS...KJP
NEAR TERM...LFR
SHORT TERM...KJP
LONG TERM...BRO
AVIATION...LFR/BRO
MARINE...LFR/BRO
FIRE WEATHER...KLW/BRO