Severe Thunderstorm Warning 257, NWS Baltimore/Washington

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
202 PM EDT Sat Aug 13 2016

.SYNOPSIS...

High pressure remains over the western Atlantic through the
weekend. A weakening cold front will drop across the Mid Atlantic
before dissipating early next week.

&&

.NEAR TERM /TONIGHT/...
Currently seeing heat index values of 105 to 110 over much of the
area from the Blue Ridge east. Heat warnings and advisories will
remain in effect into the evening hours.

For the remainder of the afternoon/this evening we'll be keeping
an eye on isolated developing thunderstorms. The wind fields are
weak - the Cu outside our window are essentially stationary. Also
interesting is the the IAD morning sounding had a freezing level
of over 16K feet. Not a record but very high. Any storm that does
form will have the potential to produce brief heavy rainfall.

Air temperatures will stay above 80 across the majority of the
region through midnight... and in the cities/along the Bay all
night.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...

The syoptic pattern will remain in place Sunday bringing the east
coast another day of heat and humidity. An excessive heat watch is
in effect for many of the DC/Balt environs. Additional heat
advisories  will most likely be issued by evening shift.

SPC has placed the an area from the Potomac north to the Mason
Dixon Line in a marginal risk for severe thunderstorms. Obviously
anything that forms would have a tremendous amount of CAPE to work
with.

Continued warmth Sunday night. Monday will likely be a few degrees
cooler but with a better chance of afternoon/evening convection.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

A weak front will linger across our region Monday night through
Wednesday. This front will be the focal zone of showers and
thunderstorms, mainly during the afternoon.

The front should slide to the southeast Wednesday night through
Thursday night. There is still a chance for showers or a
thunderstorm even on the north side of the front and across the
Virginia Piedmont.

High pressure will build over New England and eastern Canada Friday
through Saturday. This high could nose southward into our region by
early need weekend. However, the chance for showers and
a thunderstorm still exist over the Potomac Highlands and along the
I-81 corridor Friday into Friday night.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

VFR conditions expected tonight through Monday with the exception
of when any scattered thunderstorms move over an airport.

MVFR or perhaps brief IFR conditions could develop with showers
and thunderstorms Tuesday and Tuesday evening. Otherwise, VFR conditions
expected.

&&

.MARINE...

Marginal SCA in effect for the widest part of the MD portion of
the Chesapeake Bay through Sunday. Isolated thunderstorms will be
possible Sunday and Monday.

No marine hazards expected Monday night through Tuesday night.

&&

.CLIMATE...

A ranking of 2016 average temperatures Jun 1-Aug 12:

DCA  4th warmest* 80.0 degrees  (tied with 2015 and 1980)
Balt 34th warmest 76.8 degrees
IAD  7th warmest  76.7 degrees

*For DC - 5 of the top 6 have been since 2010. Records go back to 1871.

Here is a list of record high temps and record warm low temps for
DCA, BWI, and IAD for today and tomorrow.

                        Record High:       Record High Minimum

For DCA:
Saturday August 13th:  101 in 1881:        79 in 1995
Sunday: August 14th:   100 in 1943:        80 in 2002

For BWI:
Saturday August 13th:   99 in 2002:        79 in 1872
Sunday August 14th:     99 in 1985:        77 in 1947

For IAD:
Saturday August 13th:   98 in 2002:        76 in 1988
Sunday August 14th:    100 in 1985:        75 in 2002

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Excessive Heat Warning until 11 PM EDT this evening for DCZ001.
     Excessive Heat Watch from Sunday afternoon through Sunday
     evening for DCZ001.
MD...Heat Advisory until 9 PM EDT this evening for MDZ003-016>018.
     Excessive Heat Warning until 11 PM EDT this evening for
     MDZ004>006-011-013-014-503>508.
     Excessive Heat Watch from Sunday afternoon through Sunday
     evening for MDZ011-013-014-018-504-506-508.
VA...Heat Advisory until 9 PM EDT this evening for VAZ027>031-
     036>040-050-051-055>057-501-502.
     Excessive Heat Warning until 11 PM EDT this evening for
     VAZ052>054-505-506.
     Excessive Heat Watch from Sunday afternoon through Sunday
     evening for VAZ053-054.
WV...Heat Advisory until 9 PM EDT this evening for WVZ051>053.
MARINE...Small Craft Advisory until 11 AM EDT Sunday for ANZ534-537-543.

&&

PRODUCTS...WOODY!/KLW

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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
657 PM EDT SAT AUG 13 2016

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

0630 PM     TSTM WND DMG     LEVELS                  39.48N  78.55W
08/13/2016                   HAMPSHIRE          WV   911 CALL CENTER

            TREE DOWN NEAR THE INTERSECTION OF JERSEY MOUNTAIN ROAD
            AND LITTLE CACAPON-LEVELS ROAD.

&&

EVENT NUMBER LWX1604676

DH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
721 PM EDT SAT AUG 13 2016

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

0659 PM     TSTM WND DMG     4 NW CACAPON STATE PARK 39.55N  78.35W
08/13/2016                   MORGAN             WV   911 CALL CENTER

            TREE DOWN IN THE 20000 BLOCK OF CACAPON ROAD.

&&

EVENT NUMBER LWX1604677

DH