Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPBZ 041845
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
145 PM EST WED MAR 4 2015

.SYNOPSIS...
RAIN AND MIXED PRECIPITATION WILL TURN TO SNOW ACROSS THE ENTIRE
REGION THIS EVENING...WITH SEVERAL INCHES OF SNOW EXPECTED INTO
NORTHERN WEST VIRGINIA. TEMPERATURES WILL BE UNSEASONABLY COLD
INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
HAVE CLEARED THE NORTHERN TIER OF COUNTIES FROM FLOOD WATCH AS NO
ADDITIONAL RAIN OR SIGNIFICANT RUNOFF EXPECTED NORTH OF
PITTSBURGH. NO CHANGES AT THIS TIME FOR WINTER HEADLINES OR SNOW
AMOUNTS. PREVIOUS DISCUSSION BELOW.

BULK OF HEAVIER PRECIPITATION NOW HEADING INTO THE SOUTHEAST
RIDGES AS COLDER AIR ABOVE THE SURFACE PUSHES SOUTHEAST. EXPECT
RAIN ALONG I-70 TO MIX OVER TO SNOW OR A BIT OF SLEET BEFORE
DIMINISHING FOR A TIME. BOUNDARY INTO CENTRAL OHIO WITH LEADING
EDGE OF MUCH COLDER AIR WILL SAG SOUTH THIS AFTERNOON AS SURFACE
WAVE WITH SHORTWAVE ALOFT MOVES NORTHEAST ALONG BOUNDARY. SNOW
WILL REDEVELOP SOUTHWEST TO NORTHEAST ACROSS AREAS FROM
PITTSBURGH SOUTH TOWARD SUNSET AND CONTINUE INTO EARLY THURSDAY.
STILL APPEARS BEST LIFT AND QPF WILL BE ACROSS THE FAR SOUTH WHERE
WARNING IS IN PLACE. NORTH OF THIS REGION MAY BE A SHARPER CUTOFF
TO SNOW AND AMOUNTS IN THE NORTHERN SECTIONS OF ADVISORY AREA MAY
BE LOWERED A BIT LATER TODAY DEPENDING ON INCOMING DATA.

SNOW WILL DIMINISH THURSDAY MORNING WITH COLD HIGH PRESSURE
BUILDING IN THURSDAY AFTERNOON.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WEATHER PATTERN QUIETS DOWN FOR THE END OF THE WEEK AS A BROAD
AREA OF HIGH SURFACE PRESSURE PUSHES IN FROM THE WEST AND KICKS
OUT THE MID-WEEK SYSTEM. LINGERING LIGHT SNOW SHOWERS WILL
DISSIPATE QUICKLY THURS NIGHT AND SKIES WILL BEGIN CLEARING FROM
THE WEST. REMNANT SKY COVER WILL PLAY A BIG ROLE IN OVERNIGHT LOWS
HEADING INTO FRIDAY MORNING. WITH CALM WINDS AND THE PRESENCE OF A
FRESH SNOW PACK...FOR AT LEAST 1/2 OF THE CWA...ALL SIGNS POINT
TO DECOUPLING OF THE LOWER ATMOSPHERE AND TEMPERATURES BEGINNING
TO CRATER WELL BELOW AVERAGE. MET AND MAV GUIDANCE SHOW AT LEAST SOME
CLOUDS HOLDING IN DURING THE PRE-DAWN HOURS FRI...WHICH WOULD
DISRUPT EFFICIENT RADIATIONAL COOLING. THINK THIS ROUTE IS A BIT
CONSERVATIVE...AND HAVE HELD LOWS BELOW THOSE NUMBERS.

TEMPERATURES WILL WARM UP QUICKLY HEADING INTO THE WEEKEND WITH
DRIER AND CLEARER CONDITIONS EXPECTED. NEXT SYSTEM POISED TO
STREAM NORTH OF THE FORECAST AREA...EMBEDDED IN THE NORTHWEST
UPPER LEVEL FLOW. NAM/ECMWF SEEM TO HAVE THE BEST HANDLE ON THIS
RELATIVELY DRY SYSTEM...AND THEREFORE FOLLOWED THIS TO INTRODUCE
LIGHT SNOW SATURDAY EVENING.
TAX

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE LONG TERM PERIOD LOOKS RELATIVELY QUIET WITH A PROGRESSIVE
PATTERN FEATURING PASSAGE OF A COUPLE OF SHORTWAVE TROUGHS. POPS
WERE FORECAST GENERALLY BELOW CHANCE CLIMO NUMBERS USING GFS
TIMING...BUT LONG TERM CONFIDENCE IS MINIMAL WITH DOUBTS ABOUT
TIMING AND MOISTURE SUPPLY. SEASONALLY COOL TEMPERATURES WERE
FORECAST VIA PERSISTENCE AND MOS.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
LOW MVFR/IFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT AS
COPIOUS MOISTURE FLOWS NORTH AND GENERATES PRECIPITATION ALONG A
STATIONARY BOUNDARY. FOR TERMINALS NORTH AND WEST OF
LBE/MGW...SNOW WILL BE PRECIPITATION TYPE THROUGH THE DURATION OF
THE EVENT. AT LBE/MGW CURRENT RAIN WILL GRADUALLY TRANSITION TO
SNOW THIS EVENING AND REMAIN SNOW THROUGH THE NIGHT. MODERATE TO
HEAVY SNOW BANDING TONIGHT COULD RESULT IN LIFR
CONDITIONS...ESPECIALLY FOR SOUTHERN TERMINALS. FAR NORTHERN
TERMINALS SHOULD STAY OUT OF THE MODERATE SNOW...BUT MVFR/IFR
SHOULD HOLD THROUGH THE NIGHT. WITH LOW CIGS.

GRADUAL IMPROVEMENT AFTER DAYBREAK FROM WEST TO EAST.
TAX

.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
RESTRICTIONS ARE POSSIBLE WITH A SATURDAY NIGHT/SUNDAY MORNING COLD
FRONT.

&&

.HYDROLOGY...
THE COMBINATION OF SNOW MELT AND DEVELOPING RAIN IS EXPECTED TO
CAUSE SIGNIFICANT RISES ON THE CHEAT... MONONGAHELA AND
YOUGHIOGHENY RIVER BASINS. THESE RISES WILL AID IN MOVING ICE INTO
AREAS WHERE ICE JAMS ARE KNOWN TO DEVELOP. THE RISES WILL MOST
LIKELY PERSIST THROUGH THURSDAY. CONFIDENCE IN RAIN AMOUNTS
REMAINS LOW...BUT THE BETTER CHANCE FOR MORE SIGNIFICANT
ACCUMULATION IS EXPECTED TO BE ALONG AND SOUTH OF A ZANESVILLE TO
LATROBE LINE.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH UNTIL 7 PM EST THIS EVENING FOR MDZ001.
     WINTER STORM WARNING UNTIL 4 PM EST THURSDAY FOR MDZ001.
OH...FLOOD WATCH UNTIL 7 PM EST THIS EVENING FOR OHZ049-050-057>059-
     068-069.
     WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR OHZ049-050-
     057>059-068.
     WINTER STORM WARNING UNTIL 4 PM EST THURSDAY FOR OHZ069.
PA...FLOOD WATCH UNTIL 7 PM EST THIS EVENING FOR PAZ021-029-031-
     073>076.
     WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR PAZ021-023-
     029-031-073>075.
     WINTER STORM WARNING UNTIL 4 PM EST THURSDAY FOR PAZ076.
WV...FLOOD WATCH UNTIL 7 PM EST THIS EVENING FOR WVZ001>004-012-
     021>023-041.
     WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR WVZ001>004.
     WINTER STORM WARNING UNTIL 4 PM EST THURSDAY FOR WVZ012-
     021>023-041.

&&

$$






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.