National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 132243
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
643 PM EDT MON MAY 13 2013

.SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL BUILD IN THROUGH TUESDAY. A WARM FRONT WILL
CROSS THE REGION TUESDAY NIGHT...FOLLOWED BY A COLD FRONT
WEDNESDAY. THIS FRONT WILL BECOME STATIONARY ACROSS THE OHIO
VALLEY INTO THE WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
STLT SHOWS A SHRTWV EXITING THE RGN...WITH SFC HIGH PRES BLDG IN.
THIS WL QUICKLY END ANY SHWRS AND CLR OUT THE CLOUDS. AS
DECOUPLING TAKES PLACE AND WINDS DROP...EXP TEMPS TO DROP AT OR
BELOW FREEZING ACRS AREAS NR THE OH/WV BORDER EWD EVEN WITH SOME
CI MOVG IN. THE CI WL INCR OVRNGT...WHICH SHOULD HELP KEEP TEMPS
ABV FREEZING IN WRN AREAS WITH SOME VRY WK WRM AIR ADVCTN ALOFT.
KEPT THE FROST ADVY AND FREEZE WRNG AS IS. TUE HIGH PRES SHIFTS
EWD WITH SRLY FLOW. INCRG AC AND WRM AIR ADVCTN COULD BRING A SLGT
CHC OF A SHWR TO THE RGN AS WELL.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
WARM FRONT WILL PUSH NORTH ACROSS REGION TUESDAY NIGHT INTO
WEDNESDAY BRINGING A CHANCE OF SHOWERS OR THUNDERSTORMS. LOW
PRESSURE SYSTEM ASSOCIATED WITH CLOSED UPPER LOW MOVING ACROSS
EASTERN CANADA WILL THEN PULL A WEAK FRONT SOUTH ACROSS REGION
LATER WEDNESDAY INTO THURSDAY. MODELS HAVE SOME TIMING
DISAGREEMENTS WITH WHETHER FRONT WILL HANG UP NEAR THE MASON DIXON
LINE OR PUSH SOUTH. HAVE LEFT CHANCE POPS FOR SHOWERS AND STORMS
FOR NOW BUT EXPECT A PERIOD OF HIGHER POPS WILL BE NEEDED...ONCE
TIMING OF FROPA CAN BE BETTER EVALUATED. A GENERAL BLEND OF MODEL
MOS WHICH WILL GIVE ABOVE AVERAGE TEMPERATURES...ESPECIALLY BEHIND
WARM FRONT WEDNESDAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE MODELS AGREE IN A LOW AMPLITUDE RIDGE REMAINING OVER THE
CENTRAL CONUS THROUGH AT LEAST SUNDAY BEFORE A DEEPENING TROUGH
AMPLIFIES THE RIDGE AND MOVES IT EASTWARD FOR THE BEGINNING OF NEXT
WEEK. HOWEVER...THERE ARE INHERENT DIFFERENCES IN THE TIMING AND
STRENGTH OF A SERIES OF SHORTWAVES AS THEY MOVE THROUGH THE
FLOW...DECREASING CONFIDENCE THROUGH THE PERIOD. THUS...OPTED TO
KEEP NO HIGHER THAN CHANCE POPS THROUGH MUCH OF THE PERIOD...WHICH
IS RIGHT IN LINE WITH BOTH HPC/MEX GUIDANCE. BOTH THE ECMWF AND GFS
GRADUALLY WARM TEMPERATURES THROUGH THE PERIOD KEEPING TEMPERATURES
5-10 DEGREES ABOVE SEASONAL AVERAGES THROUGH THE PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
EXP VFR CONDS AND DCRG WNDS TNGT AS HIGH PRES BLDS IN. VFR SHOULD
CONT INTO TUE ALTHOUGH MID AND HIGH CLDS WL BE INCRG. WNDS EXPD TO
PICK UP OUT OF THE S TUE AT 5-10KT.

.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
SCT SHWRS/TSTMS WL BRING PSBL RESTRNS WED INTO THU. VFR EXP FRI
WITH INCRG SHWR/TSTM CHCS FOR SAT.
-- End Changed Discussion --

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR OHZ039-040-
     048>050-057>059-068-069.
     FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR OHZ041.
PA...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR PAZ007>009-
     013>016-020>023-029-031-073>076.
WV...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR WVZ001>004-
     012-021>023.

&&

$$

07