618
FXUS61 KLWX 150900 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
400 AM EST Fri Nov 15 2024

.SYNOPSIS...
Low pressure and its associated cold front will slowly push
offshore later this morning allowing precipitation chances to
subside outside the mountains. High pressure builds this weekend
bringing moderating temperatures and dry conditions.
Precipitation chances return with a strong cold front and area
of low pressure during the middle and latter half of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Closed upper level low pressure will continue offshore this morning
while surface low pressure sits off the coast of North Carolina. As
a result, expect lingering shower chances along and east of I-95 as
well as back across the Alleghenies where residual shortwave
troughing resides. Shower chances will continue along the Allegheny
Front through early Saturday as a result of this shortwave trough
slowly pivoting through. 00z and 06z have trended slower when
it comes to both decreasing clouds and light precipitation
chances this morning. With that said, have held onto both a bit
longer mainly east of the Blue Ridge and west of the Alleghenies
with the dry slot winning out in between mid to late afternoon.
Of course, all of this will depend on how quickly the parent
low pressure system exits the area this morning.

Skies will slowly clear this afternoon and evening with a mix of sun
and clouds expected. This is due in part to building high pressure
that will control the weather for the start of the upcoming weekend
ahead. High temperatures today in the mid/upper 50s (40s to low 50s
for mountain locations). Lows tonight will fall into the upper 30s
and lower 40s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Dry and seasonable conditions are expected throughout the weekend
with highs in the upper 50s and low 60s. Mountain locations will be
touch cooler with upper 40s and low 50s Saturday, warming into the
mid 50s Sunday. Lows Saturday night will fall back into the mid to
upper 30s. Sheltered valley locations will radiate out into the
upper 20s and low 30s. Sunday night lows will moderate into the
upper 309s and low to mid 40s.

The only hazard within the short term period is fire weather for
central and northeast portions of Maryland. This is largely due in
part to a lack of rainfall in these locations (i.e amounts less than
0.10" over the past 24 to 36 hours). The lack of rainfall, prolonged
drought, and increased winds Saturday (gusts up to 20 kts) will lead
to elevated fire concerns.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Strong upper level ridging will continue to dominate through at
least Wednesday with a big pattern change late next week. A weak
shortwave trough passing to the north will drop a weak cold front
into the area Monday. A shower or sprinkle is possible with this
front west of the Allegheny Front. High temperatures Monday will
push into the mid to upper 60s and low 70s east of the mountains.
Lows Monday night will fall into the upper 30s and low 40s.

The weather pattern begins to transition a bit Tuesday into
Wednesday. Synoptically, we remain sandwiched between cutoff low
pressure over the northwest Atlantic and mid-Mississippi River
Valley. A flattening ridge and diffuse frontal zone remains in
between the two low pressure systems translating to increased cloud
cover and mountain rain showers. Highs Tuesday will be slightly
cooler in the upper 50s and low to mid 60s under added cloud cover.

Bigger changes to the weather pattern arrive Wednesday into the
latter half of the workweek. Upper level low pressure over the mid-
MS River Valley will eject eastward into the Ohio River Valley. A
strong cold front will accompany this system sometime Thursday into
Friday. 00/06z guidance is in somewhat better agreement on the
timing of the front, but uncertainty remains given subtle
differences amongst the placement of the deep digging trough within
both the deterministic/ensemble guidance. No significant weather
impacts are expected over the next 7 days, but will continue to
monitor given the upcoming holiday travel period.

What we do know is that a definitive cool-down is on the way
for the Thanksgiving holiday. This continues to be highlighted
in the 8-14 day temperature trends from the Climate Prediction
Center. Moderate winds and snow threats are also highlighted for
this same period are the Appalachians region.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
MVFR to patchy IFR vsbys and IFR to LIFR cigs will continue this
morning as low pressure slowly exits the area. Residual light to
moderate shower/drizzle activity will linger at terminals east of a
line from KMRB down to KCHO through at least 13-15z/8am-10am. Beyond
this point, drier air will take over with MVFR conditions expected
later this morning and VFR conditions returning to all terminals
later this afternoon. Winds will remain out of the E/NE this morning
a 5-10 kts with a few gusts up to 18 kts at terminals closest to the
waters (i.e KBWI/KDCA). Winds will turn to the northwest this
afternoon with gusts running between 15 to 20 kts.

VFR conditions continue through Saturday night. Wind will be the
only impact to aviation this weekend with northwesterly gusts
running 15 to 25 kts. Winds will slacken while switching to the
southwest Sunday. VFR conditions will continue during this time with
added mid and high level cloud cover.

No significant weather is Monday or Tuesday outside of a few
mountain showers west of KMRB. Winds will turn back to the
west/northwest with gusts up to 15 kts Monday. Next chance of sub-
VFR conditions arrive with another strong cold front and low
pressure system by the middle and end of next week.

&&

.MARINE...
SCA conditions look to continue across all waters
through Saturday morning. East to northeast winds this morning
will switch to the northwest this afternoon into Saturday. Gusts
of 15 to25 kts are expect through this evening. Winds will
increase tonight into Saturday as the gradient tightens between
departing low pressure offshore and incoming high pressure from
the Ohio River Valley. Gusts of 20 to 30 kts are possible
Saturday especially over the open waters. Winds will slowly
diminish late Saturday night into Sunday as high pressure builds
overhead.

Sub-SCA level winds return late Sunday morning into Monday with high
pressure overhead. Winds will switch back to the southwest Sunday
before turning to the west and northwest Monday with gusts less than
15kts. A weak upper-level disturbance swinging through Monday night
into Tuesday could briefly kick winds back up out of the NW, which
could near SCA criteria. Additional SCA conditions are possible mid
to late next week as a strong front and low pressure cross the
region.

&&

.FIRE WEATHER...
Decreased fire weather conditions today due to recent precipitation
and added cloud cover. Rainfall amounts range from a few one
hundredths across northeast MD to upwards of an inch across the
central/southern Shenandoah Valley.

Drier air returns with high pressure and gusty north to northwest
flow for the start of the weekend. Wind gusts up to 20 kts are
possible Saturday with minimum RH values falling back into the 40 to
50 percent range. Similar minimum RH conditions (35 to 45 percent)
are expected Sunday with wind gusts less than 15 kts.

Highest potential for elevated fire weather conditions this weekend
into early next week would be across northeast MD and the MD/PA line
where rainfall totals were less than a tenth of an inch over the
past 36 hours. The added drought in these locations will further
this concern.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will remain elevated due to onshore flow through
this morning, before offshore flow lowers anomalies tonight. Minor
flooding is anticipated at Annapolis and Washington DC SW Waterfront
through this afternoon, with near minor possible at several other
sites until water levels recede.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until midnight EST tonight for DCZ001.
MD...Small Craft Advisory until 6 PM EST Saturday for MDZ008.
     Coastal Flood Advisory until 10 PM EST this evening for MDZ014.
     Coastal Flood Advisory until 4 PM EST this afternoon for
     MDZ016-018.
VA...Coastal Flood Advisory until midnight EST tonight for VAZ054.
     Coastal Flood Advisory until 4 PM EST this afternoon for
     VAZ057.
WV...None.
MARINE...Small Craft Advisory until 6 PM EST Saturday for ANZ530>534-
     536>543.
     Small Craft Advisory from 7 AM to 6 PM EST Saturday for ANZ535.

&&

$$

SYNOPSIS...EST
NEAR TERM...LFR
SHORT TERM...LFR/EST
LONG TERM...LFR/EST
AVIATION...LFR/EST
MARINE...LFR/EST
FIRE WEATHER...EST
TIDES/COASTAL FLOODING...EST