Special Weather Statement, NWS Pittsburgh, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1114 PM EDT SAT AUG 4 2012

.SYNOPSIS...
A COLD FRONT CROSSING SUNDAY WILL BRING A DAMP END TO OUR WEEKEND.
HIGH PRESSURE WILL BUILD OVERHEAD FOR THE BEGINNING OF THE WORK
WEEK. TEMPERATURES ARE PREDICTED TO REMAIN AT SEASONAL LEVELS
THROUGH NEXT WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
A RICH POOL OF LOW-LEVEL MOISTURE CONTINUES TO FEED AN EASTWARD
STREAKING SQUALL LINE THROUGH CENTRAL OHIO AS OF 11 PM. WHILE
LIGHTNING TRENDS HAVE WEAKENED WITH THE LINE IN THE PAST HOUR
SOMEWHAT...RADAR REFLECTIVITY TRENDS ARE NOT YET DOWNWARD NEARLY
AS MUCH...NOR ARE RADAR 0.5 DEGREE VELOCITIES FROM KCLE. A FEW
PIXELS OF AROUND 50 KTS HAVE STILL BEEN NOTED IN THE RECENT PAST
ALONG THE BOWING SEGMENT AT THE APEX OF THE SQUALL LINE...AND
WIDESPREAD 60 DBZ ECHOES ARE STILL PRESENT IN THE LINE. SURFACE-
BASED CAPE VALUES ARE NOT HORRIBLY IMPRESSIVE AHEAD OF THE SYSTEM
IN EITHER EASTERN OHIO OR NORTHERN PENNSYLVANIA...BASICALLY
RUNNING SUB-2000 J/KG EVERY...WITH A TREND TOWARD THE 500-800 J/KG
RANGE IN THE NEXT SEVERAL HOURS. HOWEVER...THE EASTWARD SPREADING
COLD POOL WILL LIKELY GIVE ENOUGH HELP FOR CONVECTIVE ASCENT IN
THE MOISTURE-RICH AND MARGINALLY UNSTABLE ATMOSPHERE AHEAD OF THE
SQUALL LINE TO KEEP IT TRUCKING EASTWARD FOR AT LEAST THE NEXT FEW
HOURS. IT WOULD CERTAINLY SEEM EVEN WITH SUBSTANTIAL ELEVATED
INSTABILITY REMAINING OVERNIGHT...SURFACE-BASED INSTABILITY
DECREASING TRENDS SHOULD WEAKEN THIS LINE AS IT MOVES INTO
PENNSYLVANIA. HOWEVER...POPS WERE INCREASED QUITE A LOT TO ACCOUNT
FOR ITS EXPECTED ARRIVAL ACROSS THE NORTHWESTERN PORTIONS OF THE
FORECAST AREA.

OTHERWISE...CONVECTIVE DEBRIS CLOUDS SEEM POISED TO DOMINATE THE
NIGHT WITH A POOR RADIATIONAL COOLING NIGHT EXPECTED. THE CAVEAT
TO THIS BEING THAT SOME EVAPORATIONAL COOLING WILL BE LIKELY IN
AREAS THAT RECEIVE RAINFALL...SO LOWS WERE NOT RAISED
SUBSTANTIALLY FROM WHERE THEY WERE PREVIOUSLY FORECAST. FRIES

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
THE COLD FRONT SHOULD BE PUSHING ITS WAY ACROSS PA SUNDAY NIGHT.
WITH THE WIDESPREAD NATURE OF PRECIPITATION...CONTINUED
CATEGORICAL POPS THOUGH MIDNIGHT. THE NAM IS FASTER THAN THE GFS
WITH PULLING THE FRONT/PRECIPITATION THROUGH THE RIDGES BY LATE
SUNDAY NIGHT/MONDAY MORNING. THE ECMWF AND GFS ARE JUST SLIGHTLY
SLOWER. THUS...OPTED TO DO A COMPROMISE WHICH THE SREF SEEMS TO
HANDLE APPROPRIATELY...KEEPING SLIGHT CHANCE POPS IN THE RIDGES
THROUGH 12Z MONDAY.

HIGH PRESSURE BUILDS IN BEHIND THE FRONT FOR THE LATTER HALF OF
MONDAY AND TUESDAY RETURNING TEMPERATURES CLOSER TO NORMAL AND
BRINGING DOWN HUMIDITY LEVELS.

KEPT CLOSE TO MAV/MET TEMPERATURES THROUGH THIS PERIOD...WHICH ARE
SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WEAK HIGH PRESSURE SHOULD KEEP CONDITIONS DRY TUESDAY
NIGHT...ALTHOUGH THE FORECAST AREA COULD BE SQUEEZED FROM THE
NORTHWEST AND SOUTHEAST FOR SHOWERS ON WEDNESDAY AND THURSDAY...AS A
FRONT WILL REMAIN DRAPED ALONG THE GREAT LAKES AND ANOTHER FRONT
WILL BE DRAPED ALONG THE EAST COAST. BEST CHANCE FOR SHOWERS/STORMS
AT THIS POINT APPEARS TO BE ON FRIDAY...WITH BEST ENSEMBLE CONSENSUS
FOR FRONTAL PASSAGE OCCURRING DURING THIS TIME PERIOD. ONCE THE
FRONT CLEARS FRIDAY NIGHT...NORTHWEST FLOW FROM A LOW PRESSURE
CENTER IN ONTARIO WILL BRING ADDITIONAL MOISTURE OFF LAKE ERIE. THIS
COULD BRING SOME ISOLATED SHOWERS...BUT WILL ALSO BRING COOLER AIR
INTO THE REGION. WHILE HIGHS WILL BE IN THE 80S FOR THE SECOND HALF
OF THE WORK WEEK...PRELIMINARY FORECAST FOR SATURDAY KEEPS MOST
LOCATIONS IN THE 70S.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
ISOLATED THUNDERSTORMS ACROSS REGION WITH A COUPLE CELLS
APPROACHING ZVV THROUGH 01Z OR SO. OTHERWISE 2 SEPARATE MCS ACROSS
INDIANA AND OHIO LOOK TO BE SHIFTING NORTHWARD THROUGH THE EVENING
AHEAD OF ADVANCING COLD FRONT. APPEARS ONLY ISOLATED SHOWERS OR A
THUNDERSTORM AHEAD OF MAIN ACTIVITY FOR TERMINALS OVERNIGHT THEN
MORE WIDESPREAD SHOWERS AND STORMS WITH MVFR ACROSS EASTERN OHIO
TOWARD DAYBREAK SPREADING EASTWARD ACROSS REGION THROUGH MIDDAY SUNDAY.

FRONT WILL CROSS REGION TO RIDGES BY 00Z MONDAY WITH CONTINUED
SHOWERS AND A FEW STORMS. SOUTH WINDS OVERNIGHT WILL BECOME
SOUTHWEST TO WEST DURING THE DAY SUNDAY NEAR 10 KTS WITH HIGHER
GUSTS IN THUNDERSTORMS.

OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
COLD FRONT WILL SHIFT EAST OF REGION SUNDAY NIGHT WITH SHOWERS ENDING.
RESTRICTIONS WITH FOG WILL BE POSSIBLE MONDAY MORNING. GENERALLY
VFR WILL PREVAIL MONDAY INTO THURSDAY UNDER HIGH PRESSURE.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
327 PM EDT SAT AUG 4 2012

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021>023-041-051930-
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-PRESTON-TUCKER-
327 PM EDT SAT AUG 4 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST
CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST
PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA
AND NORTHERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE MAIN THREAT WILL BE DAMAGING
WINDS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1229 AM EDT SUN AUG 5 2012

OHZ039-048-050515-
COSHOCTON OH-TUSCARAWAS OH-
1229 AM EDT SUN AUG 5 2012

...STRONG THUNDERSTORMS WILL AFFECT COSHOCTON AND NORTHWESTERN
TUSCARAWAS COUNTIES...

AT 1226 AM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 3 MILES
NORTH OF MILLERSBURG TO 6 MILES SOUTHWEST OF MARTINSBURG...MOVING
EAST AT 30 MPH.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS. HEAVY RAIN WILL
POND WATER ON ROADS AND QUICKLY FILL DITCHES AND SMALL STREAMS.
INTENSE LIGHTNING CAN BE EXPECTED FROM THESE STORMS. MOVE INDOORS
WHEN A THUNDERSTORM APPROACHES. DO NOT SEEK SHELTER UNDER TREES.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  WALHONDING...         NEW GUILFORD...       LAYLAND...
  NELLIE...             BLISSFIELD...         WARSAW...
  COOPERDALE...         SUGARCREEK...         BALTIC...
  STRASBURG...          COSHOCTON...          CONESVILLE...

PLEASE REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...877-633-6772.

LAT...LON 4046 8218 4045 8168 4064 8167 4065 8150
      4017 8170 4020 8219 4025 8221

WOODRUM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
120 AM EDT SUN AUG 5 2012

OHZ039-040-048-058-050600-
CARROLL OH-COSHOCTON OH-GUERNSEY OH-TUSCARAWAS OH-
120 AM EDT SUN AUG 5 2012

...STRONG THUNDERSTORMS WILL AFFECT EASTERN COSHOCTON...NORTHWESTERN
GUERNSEY...TUSCARAWAS AND WESTERN CARROLL COUNTIES...

AT 116 AM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 5 MILES
NORTHEAST OF BOLIVAR TO 3 MILES NORTH OF FERNCLIFF...MOVING EAST AT
30 MPH.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS. HEAVY RAIN WILL
POND WATER ON ROADS AND QUICKLY FILL DITCHES AND SMALL STREAMS.
INTENSE LIGHTNING CAN BE EXPECTED FROM THESE STORMS. MOVE INDOORS
WHEN A THUNDERSTORM APPROACHES. DO NOT SEEK SHELTER UNDER TREES.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  WEST LAFAYETTE...     SUGARCREEK...         STRASBURG...
  DOVER...              COSHOCTON...          CONESVILLE...
  BOLIVAR...            BALTIC...             BAKERSVILLE...
  PLAINFIELD...         STONE CREEK...        MINERAL CITY...

THIS WILL IMPACT THE FOLLOWING HIGHWAY...

I-77 IN OHIO BETWEEN MILE MARKERS 54 AND 95.

PLEASE REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...877-633-6772.

LAT...LON 4019 8202 4045 8188 4045 8168 4064 8167
      4065 8149 4067 8146 4066 8140 4066 8125
      4073 8123 4073 8112 4011 8142

WOODRUM