Area Forecast Discussion
Issued by NWS Sterling, VA

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262
FXUS61 KLWX 191824
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
224 PM EDT Wed Jun 19 2024

.SYNOPSIS...
High pressure will remain anchored offshore through the week,
resulting in a prolonged period of heat. The hottest days will
be Saturday and Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure will remain directly overhead through Thursday
promoting large scale subsidence/sinking motion and no
convection in the local area. Given the position of the high,
low-level flow will be off the Atlantic. This coupled with a
slight increase in high-level cirrus will result in slightly
lower temperatures than those of the past view days. Tds are
also fcst to drop today potentially below 60F and remain in the
comfortable range through Thursday. No heat headlines planned
for today or Thursday. Lows will remain near or above 70.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
High pressure will drift westward Friday while sfc to 850 mb
high moves further inland causing winds to veer more from the
south or southwest direction, coming from a continental
trajectory as opposed from oceanic direction. Temperatures on
Friday are expected to soar into the upper 90s and may approach
the century mark across western areas. Heat Advisories may be
needed for western areas. Still keeping fcst dry for most
Friday, though cannot rule out isolated convection across the
Mason-Dixon.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The hottest temperatures of the ongoing heat wave are anticipated
this coming weekend, with daytime highs climbing into the mid-upper
90s. Some locations may even reach 100 on Sunday. Dewpoints will
also increase into the upper 60s and lower 70s, making it feel more
humid. Peak heat indices in excess of 100 look to be a good bet for
much of the forecast area this weekend. There will also be lesser
relief at night, with lows only dropping into the mid-upper 70s to
the east of the Blue Ridge.

Gradual height falls aloft combined with daytime heating may lead to
a few pop up afternoon or evening thunderstorms on Saturday, but
overall coverage is expected to remain low. By Sunday into Monday,
an upper trough will approach from the Great Lakes, leading to
increased chances for afternoon and evening thunderstorms.
Ensemble guidance shows a fair amount of variance with respect to
the timing of this disturbance and its associated cold frontal
passage, but the majority of solutions show the front passing
through Monday. Depending on the timing of this system, there
could be a threat for severe thunderstorms as flow aloft increases
atop a very hot and humid airmass. If the front were to progress
slower and hold up to our north, it could potentially be very hot
(near 100) again Monday, but more solutions than not show the front
passing through sometime Monday, leading to slightly cooler
conditions (highs in the lower 90s). There`s a greater consensus
amongst guidance that we`ll be within a post-cold frontal airmass by
Tuesday, leading to dry conditions. It will still be hot however,
with highs forecast to be in the lower 90s.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Lots of high clouds today and Thursday, then clear on Friday.
SE winds around 10kt during the day becoming light south during
the night.

Prevailing VFR conditions and southerly winds are expected at the
terminals on both Saturday and Sunday. A pop up afternoon or evening
thunderstorm may be possible either day.

&&

.MARINE...
A few hours (2-4 hrs) of SCA gusts are possible each evening
across the southern waters. Otherwise, S to SE winds 10 to 15kt.

Winds may reach low-end SCA values in channeled southerly flow both
Saturday and Sunday afternoon/evening. SMWs may also be needed for
any thunderstorms that move over the waters.

&&

.CLIMATE...
Hot temperatures are expected much of this week and especially
this coming weekend. The hottest days appear to be Friday through
Sunday when several records could be in jeopardy. Below is a list
of record high temperatures for Jun 21st, 22nd, and the 23rd
and the year the record was set, and the current forecast high
temperatures for those days. RERs are only issued for DCA, IAD,
BWI, and MRB, but other sites are shown for reference.

                                     Friday Jun 21st
Climate Site                  Record High     Forecast High
Washington-National (DCA)     99F (2012)          95F
Washington-Dulles (IAD)       98F (1988)          97F
Baltimore (BWI)              100F (2012+)         95F
Martinsburg (MRB)            102F (1931)          94F
Charlottesville (CHO)         99F (1933)          96F
Annapolis (NAK)              100F (1988)          90F
Hagerstown (HGR)              97F (1923)          96F

                                    Saturday Jun 22nd
Climate Site                  Record High     Forecast High
Washington-National (DCA)    101F (1988)          97F
Washington-Dulles (IAD)       99F (1988)          97F
Baltimore (BWI)              100F (1988)          95F
Martinsburg (MRB)            102F (1933)          93F
Charlottesville (CHO)        101F (1933)          98F
Annapolis (NAK)              101F (1988)          91F
Hagerstown (HGR)             100F (1988)          95F

                                    Sunday Jun 23nd
Climate Site                  Record High     Forecast High
Washington-National (DCA)     98F (1988)          98F
Washington-Dulles (IAD)       96F (1988)          99F
Baltimore (BWI)               97F (2010)          98F
Martinsburg (MRB)            100F (1934)          95F
Charlottesville (CHO)        100F (1894)         100F
Annapolis (NAK)               98F (1988)          95F
Hagerstown (HGR)              98F (1988)          96F

&&

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

&&

$$

SYNOPSIS...LFR
NEAR TERM...CPB
SHORT TERM...CPB
LONG TERM...KJP
AVIATION...KJP/CPB
MARINE...KJP/CPB
CLIMATE...LFR