Gale Warning 7, NWS Baltimore/Washington

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
310 PM EDT Thu Apr 9 2020

.SYNOPSIS...
A cold front will exit to the east tonight while low pressure
deepens near Maine. The strong low will remain nearly stationary
through Friday, then high pressure will be able to build
overhead Saturday. Low pressure will affect the area Sunday
into Monday. High pressure builds back into our region through
the middle parts of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Convective/severe threat has ended, so the Severe Thunderstorm
Watch has been cancelled. Wind Advisory was extended in time
until 7 PM (some strong gusts possible through sunset) as well
as down the east side of the Blue Ridge (strong enough wind
fields plus downsloping effects are resulting in 40 kt gusts in
the lee of the mountains). The peak gusts of the day likely are
occurring or have occurred (west of I-95) with the immediate
pressure surge behind the front, which is now pressing through
southern Maryland.

As low pressure deepens and slows down near Maine, low level
wind fields will remain strong through the night. Should be
below advisory levels (except perhaps on the ridges), but
elevated gusts will likely continue through the night. Vorticity
rotating around a closed upper low to our north may result in a
few showers across northern areas through this evening. Snow
showers (and perhaps squalls) will be found along the Allegheny
Front, although accumulations should generally remain below
advisory criteria. Cold advection will result in lows in the 30s
to lower 40s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
The low will remain nearly stationary near the Canadian
Maritimes through Friday while high pressure attempts to build
in from the west. This will keep a tight pressure gradient
across our area, so winds should increase again after sunrise.
Will allow subsequent shifts to determine if additional Wind
Advisories will be needed. Upslope snow showers will begin to
diminish as the upper low pivots away. Otherwise expect a mix of
clouds and sun with much cooler high temperatures in the 40s to
mid 50s.

The gradient winds will continue to weaken Friday evening and
into Saturday as the surface low continues to lift northeastward
away from our region. As winds become light and cooler air
moves into our region, we may need to issue some frost/freeze
headlines for portions of our forecast area Friday night into
Saturday morning. High pressure will be firmly in place over our
region Saturday with winds becoming light. Temperatures will be
continue to be cooler with daytime temps in the 50s and lower
60s. A warm front will lift north of our area late Saturday
night. A lead vort max ahead of the next system may try to
produce a shower or sprinkle across western areas, but most
areas should remain dry. Temperatures will moderate a bit into
the upper 30s to mid 40s.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Dry conditions are likely early Sunday with high pressure offshore.
However a potent shortwave diving south out of the Texas Panhandle
will generate a strong area of low pressure over the Gulf of Mexico.
Rain will begin developing Sunday evening as the low tracks
northeastward along the Appalachians. Guidance has been very
consistent with this system in regards to the abundance of rainfall
associated with it. PWAT anamolies based on ensemble guidance
continues to remain 2 to 2.5 standard deviations above normal. Ample
moisture coupled with strong jet dynamics signal periods of heavy
rainfall through the day Monday. Overall, expect a general 1-2
inches of rainfall across the region. In terms of any possible
severe weather poised for Monday, confidence remains low at this
time given low CAPE values and weak mid-level lapse rates. However
given the high shear profile, could be enough to cause locally
damaging winds and perhaps a spin up. The best chance for this to
occur would be late Sunday night through midday Monday as the low's
associated cold front moves through the CWA. On a positive note,
this is a quick moving system and most, if not all, precip will
cease by Monday night.

Weak high pressure will move overhead for Tuesday, giving us a break
in the action. However, the jet stream remains quite active as most
of the continental US remains under a longwave trough. Model guidance
begins to diverge after Tuesday in regards to another shortwave
pulse that could generate another low over the Gulf of Mexico. The
ECMWF develops it just to our southeast, which would set us up
for a similar situation to Monday's system. However the GFS
develops this low further offshore, which would keep our area
drier. In any case, expect the long term pattern to remain
unsettled, with cooler than normal temperatures developing after
Monday through the end of next week.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Cold front has passed through the terminals. Strongest wind
gusts probably occurred immediately in the wake of the front.
However, strong background westerly winds to around 40 kt will
likely continue until sunset. A few showers or sprinkles may be
near BWI/MTN/MRB through this evening but shouldn't pose any
ceiling/visibility issues. While winds diminish some overnight,
some 20-30 kt gust will remain likely.

Strong westerly winds will continue into Friday with gusts of 25 to
40 knots possible. Winds are expected to slowly taper off
Friday evening and into Saturday. No flight restrictions are
expected Friday and Saturday.

VFR conditions are likely early Sunday before CIG/VSBY restrictions
ensue by Sunday evening as rain develops across the region. IFR/LIFR
conditions are likely Monday with periods of heavy rain and possible
thunderstorms. Low-level wind shear is also of concern given a very
strong wind field aloft. Gusty winds are also likely and even
damaging winds cannot be ruled out at this time. Conditions are
likely to improve by Monday evening as the low quickly moves away
from the terminals.

&&

.MARINE...
Strong west winds are occurring in the wake of a frontal
passage. Gale Warnings remain in effect through the afternoon,
and may need to be extended into the evening for portions of the
waters. Generally SCA winds expected overnight, but will
increase again after sunrise. Portions of the waters may need a
Gale Warning, but am letting subsequent shifts make that
determination. SCA conditions will continue through Friday night
before diminishing Saturday as high pressure builds overhead.

Low pressure will track northeastward Sunday evening into Monday.
Gusty south to southeast winds are likely, with the strongest winds
most likely Sunday night into Monday morning. Periods of heavy rain
and perhaps even a couple thunderstorms are expected. Gusty to
damaging winds are possible in any thunderstorms that develop. A
brief waterspout is possible as well, given a very strong wind field
aloft. Confidence for this to occur is low at this time.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Wind Advisory until 7 PM EDT this evening for DCZ001.
MD...Wind Advisory until 7 PM EDT this evening for MDZ003>006-011-
     013-014-501>508.
VA...Wind Advisory until 7 PM EDT this evening for VAZ025>031-
     036>040-052>054-501-503>508.
WV...Wind Advisory until 7 PM EDT this evening for WVZ050>053-055-
     501>506.
MARINE...Small Craft Advisory from 6 PM this evening to 6 AM EDT Friday
     for ANZ530>543.
     Gale Warning until 6 PM EDT this evening for ANZ530>543.

&&

SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...MSS
AVIATION...ADS/MSS
MARINE...ADS/MSS

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
557 PM EDT Thu Apr 9 2020

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-102200-
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-
557 PM EDT Thu Apr 9 2020

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...Tonight

A Wind Advisory is in effect for the Baltimore and Washington
Metropolitan areas until 8 PM this evening. Westerly winds will
gust around 50 mph.

A Gale Warning is in effect for all waters until 8 PM this
evening.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

West to northwest wind gusts around around 50 mph are possible
Friday. A Wind Advisory may be needed.

A Gale Warning may be needed for the waters Friday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed today.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-102200-
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-
557 PM EDT Thu Apr 9 2020

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...Tonight

A Wind Advisory is in effect for northern and central Maryland,
northern Virginia, the Virginia foothills, the Shenandoah Valley,
and eastern West Virginia from until 8 PM this evening. Westerly
winds will gust around 50 mph.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

West to northwest wind gusts around 50 mph are possible Friday,
especially over the higher elevations and across northern and
central Maryland, northern Virginia and eastern West Virginia. A
Wind Advisory may be needed.

Freezing temperatures are possible Friday night north and west of
the I-95 corridor. A freeze warning may be required.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed today.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
553 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     NON-TSTM WND DMG BEL AIR                 39.53N  76.35W
04/09/2020                   HARFORD            MD   EMERGENCY MNGR

            NUMEROUS REPORTS OF TREES AND WIRES DOWN ACROSS HARFORD
            COUNTY.

&&

EVENT NUMBER LWX2000998

KJP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
555 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0552 PM     NON-TSTM WND DMG 1 WSW LONDONTOWNE       38.93N  76.57W
04/09/2020                   ANNE ARUNDEL       MD   FIRE DEPT/RESCUE

            DOZENS OF REPORTS OF TREES AND/OR POWER LINES DOWN
            ACROSS ANNE ARUNDEL COUNTY.

&&

EVENT NUMBER LWX2000999

CJL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
556 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     NON-TSTM WND DMG WARRENTON               38.72N  77.80W
04/09/2020                   FAUQUIER           VA   911 CALL CENTER

            MULTIPLE TREES DOWN AND POWER LINES DOWN SCATTERED IN
            THE COUNTY. BLOWN OVER BLIND CAUSED A SMALL BRUSH FIRE
            NEAR ROCKHILL MILL ROAD. ANOTHER BRUSH FIRE WAS STARTED
            NEAR THE DELAPLAIN AREA AND POSSUM HOLLOW DRIVE.

&&

EVENT NUMBER LWX2001000

ADM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
601 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1256 PM     NON-TSTM WND GST MIDDLETOWN              39.45N  77.52W
04/09/2020  M58 MPH          FREDERICK          MD   MESONET

0100 PM     NON-TSTM WND GST SWOOPE                  38.19N  79.18W
04/09/2020  M60 MPH          AUGUSTA            VA   MESONET

0149 PM     NON-TSTM WND GST WEYERS CAVE             38.28N  78.87W
04/09/2020  M59 MPH          AUGUSTA            VA   MESONET

0244 PM     NON-TSTM WND GST HART/MILLER             39.25N  76.41W
04/09/2020  M59 MPH          BALTIMORE          MD   WXFLOW

&&

EVENT NUMBER LWX2001001
EVENT NUMBER LWX2001002
EVENT NUMBER LWX2001003
EVENT NUMBER LWX2001004

CJL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
618 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0416 PM     NON-TSTM WND DMG ELLICOTT CITY           39.27N  76.83W
04/09/2020                   HOWARD             MD   911 CALL CENTER

            LARGE TREE DOWN ON HOUSE IN 10100 BLOCK OF CENTURY
            DRIVE.

&&

EVENT NUMBER LWX2001005

KJP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
620 PM EDT THU APR 09 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0145 PM     NON-TSTM WND DMG ELLICOTT CITY           39.27N  76.83W
04/09/2020                   HOWARD             MD   911 CALL CENTER

            SCATTERED REPORTS OF TREES AND WIRES DOWN THROUGHOUT
            HOWARD COUNTY.

&&

EVENT NUMBER LWX2001006

KJP