An area of low pressure developed along the Gulf Coast on December 8th and tracked northeastward along the North and South Carolina coastlines during the daytime hours on the 9th, strengthening to around 1000mb by the evening. The low then exited eastward off the coast of Cape Hatteras and weakened on the night of the 9th.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LWX wrote it up.
An area of low pressure developed along the Gulf Coast on December 8th and tracked northeastward along the North and South Carolina coastlines during the daytime hours on the 9th, strengthening to around 1000mb by the evening. The low then exited eastward off the coast of Cape Hatteras and weakened on the night of the 9th. Accumulating snow was brought to southern Maryland, with a sharp cutoff to completely dry conditions from the Capitol Beltway northward.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Baltimore/Washington wrote its last area forecast discussion before the first event at Dec 9, 12:00 PM EST, 1 hour earlier.
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1200 PM EST Sun Dec 9 2018
.SYNOPSIS...
Low pressure developing over the northern Gulf Coast will move
toward the Carolinas today, then offshore tonight into Monday.
High pressure will build in from the Midwest late Monday through
Wednesday, before a weak system follows Wednesday night into
Thursday. A larger and potentially stronger area of low pressure
will likely impact the area by the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Noon: Surface high center has retreated to just north of
Philadelphia, as low pressure continues its east-northeastward
trek from the Big Bend area of Florida, headed toward the GA/SC
border. This is quite a dynamic system, with strong, deep
convection over Florida (where tornadic activity has been
reported). The northern edge of the snow continues its
northward creep, with flurries reported as far north as
Fredericksburg and Harrisonburg VA. Snow (heavy at times) is
present across portions of central VA (Waynesboro, Wintergreen,
Charlottesville) with 1/4 mile visibility being reported
intermittently at KW13 (Eagle's Nest Airport) near Waynesboro.
This moderate to heavy snow will continue over these same areas
for the next few hours, with 1 to 2 inches per hour likely. Some
reports of 2 to 4 inches from Nelson County are trickling in at
the moment, about a third of the way through the event. Please
see our latest Local Storm Reports and Public Information
Statements for reported snowfall totals. Further north, have
continued to make minor tweaks tightening the snowfall gradient,
but overall the forecast and headlines remain on track.
10am: Snow has begun in Waynesboro, Staunton, Charlottesville
and the surrounding areas, with reports of light snow in
Leonardtown Maryland in southern Maryland as well. Heavy snow at
times with visibility 1/4 mile or less and snowfall rates of 1-2
inches per hour are possible this afternoon given strong lift
across Augusta/Nelson/Albemarle Counties, and can't rule out up
to a foot over the higher terrain (near Wintergreen). A gradual
northward progression of snow is expected through the next
several hours, with flurries or light snow likely from Franklin
WV to Culpeper/Warrenton VA to La Plata MD by around or shortly
after noon. Overall, forecast and accumulations appear on track.
Have nudged the 1" contour southward just a touch to tighten
the gradient based on latest trends/evolving forcing mechanisms
focused mainly south of a line from New Market to Quantico VA to
Lusby MD, as well as dry air holding firm near and north of
US-50, but no changes needed to going headlines at the moment.
8am: IAD RAOB shows abundant dry air between 3000 and 13000 feet
(850 and 600 mb). With a west to east moving system, it seems
this will be hard to overcome near and north of a line from
Petersburg WV to Dulles VA to DC to Annapolis. But it should be
reinforced that the tight gradient on the northern edge means
that you'll go from next to nothing to 1 to 2 inches over the
span of 10 to 20 miles. Further south, mesoanalysis shows where
snow is falling is in line with about 90% RH in the dendritic
snow growth zone with cloud bases below 8000 feet. This should
reach a line from Staunton to Orange by about 10am. Temperatures
are cold enough that snow should stick on all surfaces right
after it starts falling.
Previous AFD...
Latest surface analysis places surface low pressure over the
western Panhandle of Florida and southeastern Alabama, heading
east-northeast. High pressure is centered much closer to our
region, over central Pennsylvania, allowing cold and dry
Canadian air to dominate the region. Aloft, one shortwave trough
is located over the lower Mississippi Valley while another is
located in northern Ontario, both heading in our general
direction.
Today, surface low pressure will head for the Carolina Coast.
Warm advection with spread precip into our region from southwest
to northeast, with FGEN becoming enhanced as the strong flow
southward from the high to our north meets the southerly flow
aloft ahead of the storm. The result will be snow, with periods
of heavy snow likely across central Virginia. While dry air will
need to be overcome at the surface, expect precip to start
reaching the ground shortly in Nelson County and spread
northwards to the DC vicinity by early afternoon. There, the
precip will hit a wall as the confluence above the surface high
overwhelms the warm advection. This forecast remains tricky, as
there could be a more extreme cut-off in snowfall totals than
currently depicted... totals could quickly rise from northing on
one side to several inches over a matter of 10-20 miles
potentially, but for now, given uncertainty, have kept the
gradient relatively gentle. Warmer surface air will also result
in diminished totals over areas near the bay, but still think
enough moisture will fall into the cold, dry air mass to result
in accumulating snow in southern MD. Given recent northward
model trends, expanded both the winter storm warning and winter
weather advisory somewhat, but for the time being think the
current forecast is reasonable, lest another model shift occur
(which is possible). Given the slim margin for error with this
storm, it would be best to check back for any updates later
this morning. While at present do not expect any significant
accumulations around DC, a last minute shift is not yet
impossible.
Temps today will not rise much given plenty of cloud cover, with
highs generally in the 30s. North to northeast winds will keep
wind chills below freezing much of the day.
Tonight, the system slips out to sea, and expect snow to clear
the region by midnight, thus have kept end time for all
midnight. Clouds may even break late tonight. Lows will be
below freezing, mostly in the 20s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Monday and Tuesday will feature the return of high pressure, and
the air mass will moderate ever so slightly. Highs both days
will be in the 40s, allowing snow to start melting wherever it
does fall today. Lows at night will return to the 20s, however,
so icy patches from melting snow may be a problem.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The 500 mb pattern for the Wed-Thu timeframe will be somewhat
wavy, but ultimately believe that subsidence will be strong
enough for a dry forecast. Forecast guidance for the period
differing in the strength/position of shortwave energy; the
ultimate impact of that will be in the skycover forecast.
Neither day will be sunny. Air mass looks more saturated by
Thursday due to warm advection in advance of approaching trough
axis.
Speaking of the trough, vigorous energy will eject from the
southwestern United States, developing a deeply amplified cut-
off low tracking across the southern United States. Ample
moisture will be available for this system, and thermal profiles
suggest rain for most of the event. Considering precipitable
water surges past an inch in December suggests that there will
be plenty of rain to be had. The only question remains how
quickly will the initial cold air retreat. Latest guidance cycle
continues to suggest borderline temperatures at best late
Thursday into early Friday, while carrying a chance of precip.
If this were to happen, the intrusion of warm air aloft
indicates a wintry mix of some kind (there would be too much
warm air for just show/rain). Have rephrased grids accordingly,
without getting caught up in too many details. After that,
p-type much easier-- rain.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR likely for MRB/IAD/DCA/BWI/MTN. South of here is where most
of the snow should stay, with LIFR likely at CHO for a time this
afternoon. Can't rule out very brief restrictions from flurries
or brief light snow at IAD/DCA, but not enough confidence in
having it in the TAF. +SN possible INVOF CHO with 1/4SM or less
possible briefly 18-23Z.
System pulls off the coast tonight, with VFR likely to prevail
Monday through Tuesday night.
At this time, VFR conditions expected Wed-Thu. Ceilings will
start to lower Thursday night as precipitation approaches. Will
need to track how quickly precip does arrive. If it comes too
quickly, then a wintry mix would be possible at onset.
&&
.MARINE...
Low pressure moving northeast along the Carolina coast will
result in increasing winds over the middle bay and lower Potomac
today. SCA in effect from midday through tonight. SCA
extended/expanded up the Chesapeake Bay a touch through noon
Monday before gradient/northerly channeling relax.
Monday night through Tuesday night, high pressure should result
in lighter winds.
At this time, the pressure gradient appears light enough for
winds to be no greater than 10-15 kt Wed-Thu.
&&
.CLIMATE...
Rainfall totals continue to creep upward, with Baltimore
setting the annual record already. Here are the current rankings
for wettest year on record (through December 5th):
Washington DC area (DCA)
1. 61.33 inches (1889)
2. 60.83 inches (2003)
3. 60.78 inches (2018)
4. 60.09 inches (1878)
Weather records for the Washington DC area have been kept at
what is now Ronald Reagan Washington National Airport (DCA)
since 1945. Precipitation records observed downtown extend the
period of record back to 1871.
Baltimore MD area (BWI)
1. 65.67 inches (2018)
2. 62.66 inches (2003)
Weather records for the Baltimore MD area have been kept at
what is now Baltimore-Washington International Thurgood Marshall
Airport (BWI) since 1950. Precipitation records observed
downtown extend the period of record back to 1871.
Dulles VA area (IAD)
1. 65.67 inches (2003)
2. 61.30 inches (2018)
3. 59.05 inches (1972)
Weather records have been kept at what is now Washington Dulles
International Airport (IAD) since 1960.
NOTE: All climate data are considered preliminary until
reviewed by the National Centers for Environmental Information
(NCEI).
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Winter Weather Advisory until midnight EST tonight for MDZ016-
017.
VA...Winter Storm Warning until midnight EST tonight for VAZ025-036-
037-508.
Winter Weather Advisory until midnight EST tonight for VAZ026-
029-038>040-050-051-055>057-502>504-507.
WV...Winter Weather Advisory until midnight EST tonight for WVZ506.
MARINE...Small Craft Advisory until 1 PM EST Monday for ANZ533-534-537-
541>543.
Small Craft Advisory from 6 AM to 1 PM EST Monday for ANZ532.
&&
SYNOPSIS...RCM
NEAR TERM...RCM/DHOF
SHORT TERM...RCM
LONG TERM...HTS
AVIATION...RCM/HTS/DHOF
MARINE...RCM/HTS/DHOF
CLIMATE...LWXHazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 508 AM EST Sun Dec 9 2018 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-101015- 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-Southern Baltimore-Prince Georges- Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford- Prince William/Manassas/Manassas Park-Fairfax- Arlington/Falls Church/Alexandria-Stafford-Spotsylvania- King George- 508 AM EST Sun Dec 9 2018 This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and adjacent counties in central Maryland and northern Virginia as well as the District of Columbia. .DAY ONE...Today and Tonight A Winter Weather Advisory is in effect for portions of southern Maryland and eastern Virginia late this morning through this evening. One to four inches of snow is expected in this region. Minor accumulations are possible further north. .DAYS TWO THROUGH SEVEN...Monday through Saturday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotters are asked to report significant weather via standard operating procedures. MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053- 055-501>506-101015- Washington-Frederick MD-Carroll-Northern Baltimore- Extreme Western Allegany-Central and Eastern Allegany- Northwest Montgomery-Central and Southeast Montgomery- Northwest Howard-Central and Southeast Howard-Northwest Harford- Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke- Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper- Northern Fauquier-Southern Fauquier-Western Highland- Eastern Highland-Western Loudoun-Eastern Loudoun- Northern Virginia Blue Ridge-Central Virginia Blue Ridge- Hampshire-Morgan-Berkeley-Jefferson-Hardy-Western Grant- Eastern Grant-Western Mineral-Eastern Mineral-Western Pendleton- Eastern Pendleton- 508 AM EST Sun Dec 9 2018 This Hazardous Weather Outlook is for eastern West Virginia, northern and central Virginia, and central and western Maryland with the exception of Garrett County. .DAY ONE...Today and Tonight A Winter Storm Warning is in effect through this evening for portions of west-central Virginia. Heavy snow is expected, with accumulations of 3 to 9 inches. A Winter Weather Advisory is in effect through this evening for additional portions of central and northwestern Virginia as well as a small portion of eastern West Virginia. One to four inches of snow is expected across this region. Minor accumulations are possible elsewhere today into this evening, generally less than one inch. .DAYS TWO THROUGH SEVEN...Monday through Saturday A slight winter storm threat exists Thursday night into early Friday morning, primarily west of the Blue Ridge. If the threat materializes, it may cause travel disruptions. .SPOTTER INFORMATION STATEMENT... Spotters are asked to report significant weather via standard operating procedures.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1200 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1130 AM SNOW NE FISHERSVILLE 38.10N 78.97W
12/09/2018 M1.0 INCH AUGUSTA VA TRAINED SPOTTER
&&
EVENT NUMBER LWX1802961
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1213 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1202 PM SNOW KEENE 37.87N 78.56W
12/09/2018 E3.0 INCH ALBEMARLE VA SOCIAL MEDIA
&&
EVENT NUMBER LWX1802962
ADSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1214 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1200 PM SNOW 1 SW NEWCOMB HALL 38.03N 78.52W
12/09/2018 M1.1 INCH CITY OF CHARLOTTES VA TRAINED SPOTTER
&&
EVENT NUMBER LWX1802963
ADSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1231 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1205 PM SNOW 1 S BOYD TAVERN 37.97N 78.34W
12/09/2018 M1.5 INCH ALBEMARLE VA TRAINED SPOTTER
&&
EVENT NUMBER LWX1802964
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1258 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1253 PM SNOW KEENE 37.87N 78.56W
12/09/2018 M4.7 INCH ALBEMARLE VA SOCIAL MEDIA
&&
EVENT NUMBER LWX1802965
ADSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1259 PM EST SUN DEC 09 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1250 PM SNOW HARRISONBURG 38.44N 78.87W
12/09/2018 E0.5 INCH CITY OF HARRISONBU VA TRAINED SPOTTER
&&
EVENT NUMBER LWX1802966
ADSThe national radar mosaic for the moment the first event began.
2 winter weather, 1 winter storm. Local standard time, as filed.
Widespread snowfall amounts from 3 to 6 inches were observed, with a local maximum of 6.3 inches measured near Ridge.
Widespread snowfall amounts from 2 to 4 inches were observed across the region, with a local maximum of 4.5 inches measured near White Plains.
Snowfall amounts ranged from around 1 inch in the northern portion of the county to around 4 inches in the southern portion of the county. A local maximum of 4.5 inches measured near Drum Point.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2018Every state in 2018This day in weather historyWarnings in Maryland, December 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 795275, 795288, 795289.