Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
436 FXUS61 KPBZ 300118 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 918 PM EDT FRI APR 29 2016 .SYNOPSIS...
-- Changed Discussion --
DRY AND COOL OVERNIGHT INTO SATURDAY MORNING. LOW PRESSURE WILL BRING RAIN SATURDAY AFTERNOON INTO SUNDAY.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
SHOWERS HAVE EXITED THE REGION AND HAVE REMOVED POPS. ONLY SLIGHT ADJUSTMENTS TO SKY COVER OVERNIGHT. PREVIOUS DISCUSSION FOLLOWS. SHORTWAVE TROUGH MOVING ACROSS NEW YORK STATE IS TAKING BULK OF THE SHOWERS NORTH OF I-80 WITH IT. HAVE TRIMMED BACK POPS MORE QUICKLY THIS EVENING. ADJUSTED HOURLY TEMPERATURES AND DEW POINTS TO REFLECT CURRENT OBSERVATIONS. COOL ADVECTION BEHIND SYSTEM WILL DROP TEMPERATURES TO NEAR THE SEASONAL AVERAGES BY DAYBREAK.
-- End Changed Discussion --
&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... SOME CLEARING WILL BE LIKELY EARLY SATURDAY AS LOW LEVEL MOISTURE FINALLY MIXES OUT BEHIND THE SYSTEM FROM FRIDAY AND IN ADVANCE OF ANOTHER SYSTEM FOR THE LATTER HALF OF SATURDAY. IN THE INTERIM...DIURNAL MIXING COMBINED WITH A DECREASE IN LAYER MOISTURE SHOULD ALLOW FOR A PERIOD OF CLEARING IN THE INTERCESSION. HOWEVER...THIS DECREASE WILL BE FLEETING AS ISENTROPIC ASCENT AHEAD OF A NORTHEASTWARD TRANSLATING WARM FRONT WILL MEAN CLOUDS WILL AGAIN OVERSPREAD THE AREA BY LATER IN THE AFTERNOON. AFOREMENTIONED ISENTROPIC ASCENT WILL SPREAD DEEP MOISTURE AND LIFT OVER THE AREA BY SATURDAY EVENING WITH A COUPLED JET STRUCTURE LIKELY TO TRANSLATE DOWN I-70. THE COMBINATION OF THESE TWO ASSURES RAIN WILL OVERSPREAD THE AREA...AND POPS WERE THUS RAISED TO 100 PERCENT. THE WARM FRONT IS SET TO MOVE NORTHWARD AND THROUGH THE AREA BY SUNDAY MORNING...PLACING THE MAJORITY OF THE CWA INTO THE WARM SECTOR BY THAT JUNCTURE. POPS WERE WOUND DOWN A BIT IN THE WARM SECTOR...HOWEVER KEPT AT LEAST CHANCE AS THE MODE WILL EVOLVE FROM STRATIFORM TO CONVECTIVE. IN THE WARM SECTOR...THE 12Z GUIDANCE HAS TRENDED DECIDEDLY TOWARD SOME AMOUNT OF CLEARING BY THE LATE MORNING ON SUNDAY. THIS WOULD WORK TO STRONGLY DESTABILIZE THE COLUMN...AND MEAN A SECONDARY INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY ON SUNDAY AFTERNOON...PARTICULARLY SOUTH OF I-80. NAM PROFILES SUGGEST UP TO 2000 J/KG OF CAPE WITH THE VAST MAJORITY OF IT ABOVE A FAIRLY LOW FREEZING LEVEL. EVEN IN THE ABSENCE OF STRONG VERTICAL SHEAR...THIS CLOUD LEAD TO SOME HAILERS. THIS WILL NEED TO BE MONITORED GOING FORWARD TO SEE HOW THE MODELS HANDLE THE WARM SECTOR IN SUBSEQUENT RUNS. EVEN AFTER A WEAK WAVE ON SUNDAY MOVES DOWN THE FRONT AND FORCES THE SHOWERS AND THUNDERSTORMS...THE UPPER JET AXIS LOOKS TO REMAIN RELATIVELY PARKED OVER THE OHIO VALLEY. THIS MEANS MOISTURE WILL BE SLOW TO DECREASE INTO EARLY NEXT WEEK WITH SHOWER CHANCES CURTAILING PAINFULLY SLOWLY. HOWEVER...AS A DEEPER UPPER LOW DIVES TOWARD THE TENNESSEE VALLEY BY TUESDAY...THE UPPER JET AXIS SHOULD FINALLY EVOLVE SOUTHWARD ENOUGH TO DRY OUT OUR AREA. FRIES && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE EXTENDED PERIOD LOOKS TO FEATURE A VERY STRONGLY ANCHORED PATTERN OVER THE WESTERN CONUS AS A RIDGE LOOKS TO EVOLVE OVER THE INTERMOUNTAIN WEST. DOWNSTREAM TROUGHING WILL THUS EVENTUALLY BECOME ESTABLISHED OVER THE GREAT LAKES AND NORTHEAST BY THE END OF THE WEEK AFTER A DRY MID-WEEK. THIS WILL MEAN SHOWER CHANCES WILL RETURN AND TEMPERATURES WILL GENERALLY TREND NEAR OR BELOW NORMAL. FRIES && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
MVFR/PATCHY IFR CIGS SHOULD CONTINUE THRU MUCH OF TNGT WITH LOW LVL MOISTURE IN PLACE. BUILDING SFC RIDGING SHOULD RESULT IN SOME DECREASE IN LOW LVL CLOUDS...WHICH HAS ALREADY RESULTED IN VFR AT ZZV. THIS SHOULD CONTIUE ELSEWHERE OVRNGT/ERLY SAT. SOME MVFR BR IS PSBL LATE WITH THE CLRG...THOUGH INCRG CI SHOULD PRECLUDE A SIGNIFICANT VSBY DCRS. VFR IS EXPD TO RETURN SAT MRNG AS MID LVL CLOUDS INCREASE AHD OF APPROACHING LOW PRESSURE. THE LOW IS EXPECTED TO RESULT IN MVFR...AND EVENTUAL IFR...RESTRICTIONS AND RAIN LATE SAT FOR PORTS S OF I 80. .OUTLOOK /SATURDAY NIGHT THROUGH WEDNESDAY/... RESTRICTIONS ARE EXPECTED THRU MON AS LOW PRESSURE SLOWLY CROSSES THE REGION.
-- End Changed Discussion --
&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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