Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
152
FXUS61 KLWX 141400
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1000 AM EDT Fri Jun 14 2024
.SYNOPSIS...
A cold front approaching from the Ohio River Valley will cross the
Mid-Atlantic tonight. High pressure will follow this weekend. A warm
front will lift across the region Monday as high pressure shifts off
the East Coast through next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Mostly sunny conditions across the area this morning, though
clouds are starting to fill in across the Alleghenies late this
morning. Temperatures have risen to the upper 70s as of 930AM,
with low 80s in central VA. For this afternoon, did tick up max
temps a degrees higher, though still in the low 90s. Deep mixing
dropping dew points to the upper 50s to low 60s will keep heat
indices in the low to mid 90s as well.
Modified Previous Discussion:
Ample surface heating should take place this afternoon. This
will result in steep low-level lapse rates and a deeply-mixed
boundary layer up to or even a little above 850 hPa. However,
deep layer westerly flow (albeit light in the low levels) may
cause surface dew points to drop and reduce convergence, casting
uncertainty in thunderstorm coverage later today as a cold
front and parent upper trough approach from the west.
Coverage may tend to focus in a few different places: (1) along
the surface trough, (2) near the PA line closer to better large
scale forcing for ascent, and (3) near any terrain circulations
in the vicinity of the Appalachians. Effective shear likely
increases to 30-35 knots (highest north) by evening, so any deep
convection that does develop will have the potential to
organize into bands or multicell clusters. The main risk given
the largely unidirectional flow and steep low-level lapse rates
appears to be damaging wind gusts.
Timing of thunderstorms is a bit uncertain, but should focus between
4 PM to 9 PM after the initial weak wave departs, heating
maximizes, and the synoptic front/trough approach from the west.
Additional shower activity or perhaps a thunderstorm or two may
linger into the overnight hours as the parent upper trough
pivots overhead.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
High pressure will build in this weekend in the wake of tonight`s
cold front. Temperatures will be seasonable in the 80s with lower
humidity expected. The chance of rain is near 0 through the weekend
given deep dry air and large scale subsidence.
Overnight low temperatures in the 50s and 60s are expected Saturday
night, but Sunday night will be about 10 degrees warmer as high
pressure moves offshore and a warm front approaches.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A strong upper ridge is forecast to build over the Northeast and
the northern mid-Atlantic early next week with ridge reaching
maximum amplitude over the local area next Wednesday. As a
result, hot and dry weather is expected all of next week. Some
record highs appear possible, particularly Tue when records are
in the mid 90s. Records on Wednesday and Thursday are higher in
the upper 90s and will be more difficult to be broken. Some Heat
Advisories or Heat Watches may become necessary at some point
next week. Note that CPC has indicated the potential for a
flash drought onset risk in their latest Days 8-14 Hazards
Outlook valid Jun 21-27.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Prevailing VFR conditions are expected through the weekend.
A cold front will bring scattered showers and thunderstorms to
the region late this afternoon into late evening. The majority
of storms should occur between 20Z and 01Z, with possible
lingering shower activity until 07Z or so. Any strong
thunderstorm could produce brief restrictions and gusty winds.
TS coverage is a bit uncertain given deep layer westerly flow
which tends to limit things locally. However, steep low-level
lapse rates could result in gusty and erratic surface winds even
in seemingly weaker activity through this evening.
Winds shift to the W-NW-N through the evening as the cold front
crosses, with a brief period of 15-20 kt gusts possible outside
of any showers and thunderstorms. Northerly winds Saturday
become northeast Saturday night, then east to southeast Sunday.
Gusts of 15-20 knots are possible during the day Saturday.
No sig wx is expected Mon or Tue.
&&
.MARINE...
Early morning gusty winds over parts of the central Chesapeake
Bay have now decreased, and should remain below SCA criteria for
the next few hours.
A strengthening surface trough just west of the waters will
likely enhance winds just enough, and that combined with the
afternoon bay breeze should be sufficient for a period of
southerly gusts around 20 knots for the main channel of the
Chesapeake Bay between Sandy Point MD and Smith Point VA
(typical channeling area). A brief period of NW 15-20 knot gusts
is possible in the wake of a cold front this evening, with
gustier winds possible in shower or thunderstorm activity (may
require Special Marine Warnings).
Northerly winds likely gust 20-25 knots Saturday morning through
early afternoon, before diminishing and becoming northeast Saturday
night, then east to southeast Sunday through Sunday night. Dry
weather is forecast this weekend.
SCA conditions are possible all of next week due to southerly
channeling and large water vs land temperature differences of
nearly 20 degrees F.
&&
.CLIMATE...
High temperatures for next week. Below is a list of record high
temperatures for June 17th, 18th, 19th, and the 20th and the
year the record was set, and the current forecast high
temperatures for those days. Daily temperature records are
currently only maintained at DCA, IAD, BWI, and MRB. Others are
shown for reference.
Monday Jun 17th
Climate Site Record High Forecast High
Washington-National (DCA) 99F (2022) 93F
Washington-Dulles (IAD) 96F (2022) 94F
Baltimore (BWI) 96F (2022+) 92F
Martinsburg (MRB) 98F (1939+) 91F
Charlottesville (CHO) 97F (2022) 93F
Annapolis (NAK) 96F (1939) 87F
Hagerstown (HGR) 96F (1952) 92F
Tuesday Jun 18th
Climate Site Record High Forecast High
Washington-National (DCA) 97F (1944) 95F
Washington-Dulles (IAD) 94F (2018+) 95F
Baltimore (BWI) 97F (1957+) 93F
Martinsburg (MRB) 99F (1943) 92F
Charlottesville (CHO) 96F (2014+) 93F
Annapolis (NAK) 96F (1957) 89F
Hagerstown (HGR) 95F (1957) 93F
Wednesday Jun 19th
Climate Site Record High Forecast High
Washington-National (DCA) 99F (1994) 95F
Washington-Dulles (IAD) 98F (1994) 95F
Baltimore (BWI) 99F (1994) 93F
Martinsburg (MRB) 96F (1994+) 92F
Charlottesville (CHO) 97F (2018) 94F
Annapolis (NAK) 96F (1993) 89F
Hagerstown (HGR) 97F (1994) 94F
Thursday Jun 20th
Climate Site Record High Forecast High
Washington-National (DCA) 99F (1931) 95F
Washington-Dulles (IAD) 97F (1964) 96F
Baltimore (BWI) 100F (1931) 94F
Martinsburg (MRB) 98F (1931) 93F
Charlottesville (CHO) 98F (1933) 94F
Annapolis (NAK) 98F (1988) 89F
Hagerstown (HGR) 98F (1931) 95F
+ indicates that value has been reached on multiple years, with
the year displayed being the most recent.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 4 AM to 11 AM EDT Saturday for
ANZ530>532-539>541.
Small Craft Advisory from 2 PM this afternoon to 9 PM EDT this
evening for ANZ532>534-537-542.
Small Craft Advisory from 4 AM to 3 PM EDT Saturday for ANZ533-
534-537-542-543.
&&
$$
SYNOPSIS...DHOF
NEAR TERM...KRR/DHOF
SHORT TERM...DHOF
LONG TERM...LFR
AVIATION...KRR/DHOF/LFR
MARINE...KRR/DHOF/LFR
CLIMATE...LWX