Alert archive / Virginia / Severe Thunderstorm Warnings in 2016

Severe Thunderstorm Warning 230, NWS Baltimore/Washington

July 26, 2016Spotsylvania County, Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 26, 2016, 8:25 PM EDT for Spotsylvania County, Virginia. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 26, 2016, 8:25 PM EDT (00:25 UTC)
Expired: Jul 26, 2016, 9:00 PM EDT
In force: 35 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County Spotsylvania County, VA

The radar

The Sterling radar (KLWX), 89 km from the middle of the area, began a volume at 00:27 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 0.4 hours before the alert went out and 196 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1118 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1443 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Jul 26, 3:37 PM EDT, 4 hours 48 minutes earlier.

Area forecast discussion, Jul 26, 3:37 PM EDT, 4 hours 48 minutes before

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
337 PM EDT Tue Jul 26 2016

.SYNOPSIS...
A front will remain stationary across the Mid-Atlantic region
through the middle of the week. Low pressure will cross the region
Thursday night into Friday. Another cold front will approach
the area early next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Remnants of front is barely noticeable in observations this
afternoon. However, mesoanalysis depicts a gradient in CAPE across
the area with the highest to the south. This is where thunderstorms
are expected to be most concentrated during the afternoon and
evening hours. Coverage may increase toward evening as a weak
shortwave approaches. Shear and lapse rates are modest, but a few
stronger pulse or multicell storms are possible with strong wind
gusts being the primary threat. Although the greatest storm risk
will subside in the evening, can't rule out a storm or two
overnight as the boundary lingers in the area. Overnight lows will
again be muggy in the 70s east of the mountains.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
The front may move a little to the south Wednesday, but some
storms will still be possible over southern portions of the area.
The front will begin to lift back north Thursday and Thursday
night as a surface low approaches. Flow will also strengthen aloft
attendant to a short wave trough. There is still some spread in
guidance, but there could be a severe and heavy rain threat
depending on the low track. Temperatures will likely remain above
normal.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
While timing differences remain, overall depiction among long-term
guidance is for an unsettled weather pattern this weekend, as
multiple impulses rotate through broad cyclonic flow aloft. This
will help suppress temperatures back closer to normal, which will be
a welcome relief after the elevated temperatures of earlier this
week. However, even though we have been relatively dry across the
area, multiple rounds of rainfall could create some Hydro issues, as
moisture throughout the column will be plentiful.

Cold front approaches the area Sunday into Monday and is then
forecast to hang up just south of the area Monday and Tuesday.
Current forecast has our area on the "cooler" (M/U80s) and drier
side of the front Monday and Tuesday...with best precipitation
chances generally in the southern portion of the forecast area.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Storms will be most likely near CHO through evening, although a
few showers/storms may be near the DC sites as well. Cloud cover
will likely preclude much fog tonight. CHO will be the focus for
scattered storms again on Wednesday. Low pressure crossing the
area late Thursday may bring more widespread storms and rain with
more prolonged sub-VFR conditions.

Risk of showers and thunderstorms continues over the weekend, with
warm and moist atmosphere remaining and several impulses moving
through the upper-level flow.

&&

.MARINE...
The main threat through Thursday night will come from
thunderstorms producing gusty winds. This threat will greatest
over the souther waters. Gradient winds will likely remain below
15 kt as a weak front is stalled across the area.

Gradient winds remain sub-SCA Friday through the weekend, though
higher winds and waves can be expected near thunderstorms.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Heat Advisory until 8 PM EDT this evening for MDZ016>018.
VA...Heat Advisory until 8 PM EDT this evening for VAZ036-037-050-
     055>057.
WV...None.
MARINE...None.

&&

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

Hazardous weather outlook, Jul 26, 5:40 PM EDT, 2 hours 45 minutes before

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In the hours before

Local storm report, Jul 26, 5:40 PM EDT, 2 hours 45 minutes before

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Local storm report, Jul 26, 5:59 PM EDT, 2 hours 26 minutes before

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Local storm report, Jul 26, 8:23 PM EDT, 2 minutes before

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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 27, 1:45 PM EDT	Severe Thunderstorm Warning	LWX	Augusta	30 min
Jul 27, 2:29 PM EDT	Severe Thunderstorm Warning	LWX	Albemarle, City of Charlottesville	46 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2016 Every severe thunderstorm warning in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.