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000
FXUS61 KPBZ 170531
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
131 AM EDT MON JUN 17 2013

.SYNOPSIS...
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A SERIES OF UPPER DISTURBANCES WILL SPAWN PERIODIC SHOWER AND
THUNDERSTORM CHANCES THROUGH TUESDAY.
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&&

.NEAR TERM /THROUGH TODAY/...
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SHWRS CONT TO DVLP NR WEAK FRONTAL BNDRY ANALYZED TO THE NORTH OF
I 80. ALTHOUGH PRIMARY SPPRTG SHRTWV IS EXITING...RAP MDL CONTS
TO SUGGEST WEAKER IMPULSES EVIDENT IN MID LVL THERMAL TROFS.
HENCE...OVRNGT POPS HAVE BEEN ADJUSTED UPWARD TO CHC NMBRS WITH
LIMITATIONS IMPOSED VIA WANING SFC BASED INSTABILITY.

SWD PROGRESS OF THE SFC FRONT IS QNABLE GIVEN ZONAL FLOW AND
SATELLITE INDICATIONS OF A STRONGER UPSTREAM SHRTWV. THOSE
FEATURES ARE EXPECTED TO SPPRT MORE SHWR AND TSTM CHCS LTR TDA AND
THIS EVENING. FOR NOW...HAVE SHIFTED AFTN AND EVE POPS NWD AND
UPPED TO CHC NMBRS IN CONJUNTION WITH INCOMING NAM AND GFS SOLNS.

TIMING AND SFC DEWPOINT FORECAST AT MOMENT LKS TO BE SUFFICIENTLY
QNABLE THAT INSTABILITY MIGHT DIMINISH ENUF TO PRECLUDE SVR...BUT
GIVEN DEEP LYR SHEAR AND GLOOMY NAM CONVECTIVE FORECASTS...SITUATION
WL HAVE TO BE MONITORED TODAY.
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&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...
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CHC POPS WERE MAINTAINED TONIGHT...BUT SHIFTED SWD INTO TUESDAY AS
SECONDARY FRONT/OUTFLOW PROGRESS AS ANOTHER DISTURBANCE/JET
STREAK CROSS THE REGION.

DRY HIGH PRES WL BLD THEREAFTER AND SUPPRESS PCPN FOR WEDNESDAY
AND THURSDAY...BUT SEASONABLY COOL AIR UNDR TROFG ALOFT WL LIMIT
TEMP RECOVERY.
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&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
LATEST GFS AND ECMWF DETERMINISTIC SOLNS AGREED GENLY IN
DEPICTIONS OF THE PROGGED FLOW PTN OVR THE ERN CONUS FOR THE
LATTER HALF OF THE WEEK...WITH ECMWF AMPLIFYING THE PTN CLOSER TO
GFS WITH A RIDGE AXIS EXTENDING FM THE SRN PLNS ACRS THE GREAT
LAKES.

THE LONG TERM FORECAST THUS CONSERVATIVELY FEATURES TEMPS
GRADUALLY WARMING TO SLIGHTLY ABOVE THE SEASONAL AVERAGES BY THE
WEEKEND. PCPN CHCS WERE FORECAST AOB CLIMO NMBRS...BUT WERE GENLY
INCRSD USING A GFS/ECMWF BLEND FOR SHRTWV TIMING INTO THE WEEKEND.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
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SCT/ISOLD SHWRS WL RMN A POSSIBILITY TNGT AS SFC FRONT SAGS SWD AND
STALLS. IN ADDITION...SFC MSTR WL TRAP UNDR BLDG INVERSION AND
POSSIBLY SPPRT FOG AREAS BY MRNG. WITH BOTH LAMP AND NAM MOS
GUIDANCE SUGGESTING AT LEAST MVFR FOG
EVERYWHERE...HAVE PERSISTED WITH THAT FORECAST AS WELL AS IFR AT THE
MORE FAVORABLE PORTS. OTHERWISE CONFIDENCE IN PCPN PLACEMENT IS
LOW...SO MENTION WL BE OMITTED UNTIL A MORE DECISIVE SIGNAL IS
RECEIVED. AT MOMENT...SHWRS ARE NOT EXPECTED TO GENERATE IFR VSBY OR
CIGS.

IMPROVEMENT TO VFR IS EXPECTED AFTER SUNRISE...BUT MORE
RESTRICTIONS ARE POSSIBLE LTR IN THE DAY AS ANOTHER DISTURBANCE
APPRCHES AND INCRS SHWR AND TSTM CHCS...ESPECIALLY FOR PORTS N OF
I 70.

OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
PERIODIC RESTRICTIONS ARE ANTICIPATED THROUGH TUESDAY A CDFNT CROSSES
THE REGION. BLDG HIGH PRES SHOULD RTN VFR CONDITIONS FOR THE
REMAINDER OF THE WORKWEEK.
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&&

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

&&

$$