Severe Thunderstorm Warning 46, NWS Pittsburgh, PA

Area Forecast Discussion
National Weather Service Pittsburgh PA
1215 AM EDT Thu Apr 9 2020

.SYNOPSIS...
Another round of showers and a few storms are expected late tonight
into Thursday morning with a cold frontal passage. Periodic showers
and cooler weather are forecast through the end of the week.

&&

.NEAR TERM /THROUGH TODAY/...
1215 AM Update: A mesoscale convective system (MCS) is currently
tracking eastward across the Ohio Valley, with the northern end of
leading edge and associated bookend vortex tracking eastward along
and near parallel to US50. A narrow ridge of warm, moist boundary
layer air is surging immediately in front of this line, with various
ASOS recording 5-10 degree Td jumps prior to the leading convective
edge. Quasi-discrete cells are developing on the nose of the higher
theta-e air. Given current track, the majority of this convection
should pass just south of the majority of the PBZ forecast area.
That said, the northern end.. near the bookend vortex may come quite
close to Tucker County. All severe hazards (hail, wind, tor) has
already been observed with this area of the line.. so it bears
watching as it moves eastward.

North of the bookend vortex lies a trailing or northern stratiform
region with embedded convective cells. While this area doesn't pose
a severe threat, rain with occasional lightning is possible as it
tracks eastward, mainly along and south of I-70. Additionally, the
precip does seem to be mixing gusty wind of 20-30 knots to the
surface. Have adjusted the gridded forecast package to include this.

Previous Discussion:
For the evening update...have modified PoPs in line with the current
model data. Continued to include the mention of thunder late tonight,
with the best chance running right along the forecast area's southern
border. Temperatures were also updated with a blend of hires model
guidance.

Previous discussion... The next shortwave trough will rotate across
the Great Lakes tonight, taking on a neutral to negative tilt as it
does so. Another round of showers is expected to arrive after
midnight, along with a crossing cold front. A few thunderstorms are
possible as well, although any severe threat should remain to the
south of the region in an area of richer instability. Mild, above-
normal minimum temperatures are expected.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
Behind the front, steep low-level lapse rates along with deep mixing
will promote continued showers will promote continued showers through
Thursday. The mixing will also allow wind gusts of 25 to 30 knots to
develop behind the departing boundary and continue through the
afternoon.

As stacked low pressure drifts from the Great Lakes towards the
Canadian Maritimes on Friday, additional spokes of energy rotating
around it will allow for continued showers chances. A mix with and
change to snow showers is expected Thursday night and into Friday
morning. Most accumulation of an inch or less will be limited to
areas near/north of I-80 and along the ridges. The warm ground and
marginally cold temperatures will limit accumulation elsewhere to a
dusting at most.

Below normal temperatures are forecast during this period, with highs
roughly 15 degrees lower than climatology on Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
High pressure will bring dry weather Friday night through Saturday
night, with some temperature recovery thanks to flat ridging. Crossing
low pressure and upper troughing will return rain chances late this
weekend into early next week. Temperature will moderate back to the
seasonal norm through the weekend, before dropping back below normal
by the end of the extended period.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
A cold front will sweep through the region late tonight through
Thursday morning, with showers and MVFR cigs likely ahead of the
boundary. Brief dry slotting may improve conditions and limit shower
activity through the early afternoon before additional showers and
restrictions return with a secondary shortwave trough.

Gusty west to northwest winds on Thursday due a tight sfc pressure
gradient and deep mixing. Strongest winds are expected during the
afternoon and evening.

.Outlook...
Restrictions will likely continue through the rest of the work week
due to additional shortwave troughs and rounds of light
precipitation moving through the region.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
1259 AM EDT Thu Apr 9 2020

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021-509>512-100500-
Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-
Jefferson OH-Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-
Forest-Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-
Armstrong-Indiana-Washington-Greene-Westmoreland-Westmoreland Ridges-
Fayette-Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-
Monongalia-Ridges of Eastern Monongalia and Northwestern Preston-
Preston-Eastern Preston-
1259 AM EDT Thu Apr 9 2020

This Hazardous Weather Outlook is for western Maryland, east
central Ohio, northwest Pennsylvania, southwest Pennsylvania,
western Pennsylvania, northern West Virginia and the northern
panhandle of West Virginia.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

WVZ513-514-100500-
Western Tucker-Eastern Tucker-
1259 AM EDT Thu Apr 9 2020

This Hazardous Weather Outlook is for northern West Virginia.

.DAY ONE...Tonight.

A line of thunderstorms will pass through Tucker County Thursday
night, with strong damaging wind and hail possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.