341  
FXUS61 KPBZ 090247  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
1047 PM EDT THU JUN 8 2023  
   
SYNOPSIS
 
 
THERE IS A LOW PROBABILITY OF DAYTIME SHOWERS NORTHEAST AND EAST  
OF THE PITTSBURGH METRO FRIDAY AFFILIATED WITH AN UPPER LOW.  
DRY, SEASONABLE WEATHER IS EXPECTED SATURDAY BEFORE  
INTERMITTENT RAIN CHANCES RETURN NEXT WEEK WITH A PATTERN  
CHANGE.  
 

 
   
NEAR TERM /THROUGH FRIDAY/
 
 
WEAK SHORTWAVES WILL CONTINUE TO TRAVERSE THE WEST SIDE OF AN UPPER  
LOW PRESSURE CENTERED OVER THE UPPER NEW ENGLAND REGION THROUGH  
FRIDAY. MODEST MID-LEVEL MOIST AND VORT ADVECTION MAY ALLOW FOR  
AN ISOLATED SHOWER AROUND NORTHWEST PA OVERNIGHT, BUT NOCTURNAL  
INVERSIONS SHOULD KEEP THE REGION DRY. OVERNIGHT LOW TEMPERATURE  
WILL FALL 5 TO 10 DEGREES BELOW NORMAL AS FALLING PRESSURE  
HEIGHTS AND WEAK COLD ADVECTION SOMEWHAT OFFSET THE WARMING  
EFFECT OF INCREASED CLOUD COVER.  
 
AS ANOTHER SHORTWAVE CROSSES THE UPPER OHIO RIVER VALLEY FRIDAY,  
THE ENVIRONMENT WILL BECOME MORE FAVORABLE FOR SHOWER AND  
ISOLATED THUNDERSTORM ACTIVITY GIVEN INCREASED SHEAR AND FURTHER  
COOLING OF MID-LEVEL AIR TO CREATE SOME SEMBLANCE OF  
INSTABILITY. HOWEVER, CLOUD COVER WILL LIMIT SURFACE HEATING  
(DAYTIME HIGHS WILL REMAIN SEASONABLY COOL) AND KEEP  
INSTABILITY TO A MINIMA, WHILE LITTLE CHANGE TO THE NEAR- SFC  
DRY LAYER AND MOISTURE DEPTH WILL LIMIT QPF OUTPUT WITH THE  
ISOLATED/SCATTERED SHOWERS THAT DEVELOP. LOCALES FAVORED FOR AN  
AFTERNOON SHOWER WILL BE NORTH AND EAST OF PITTSBURGH, WITH THE  
PROBABILITY OF SEEING GREATER THAN 0.10 INCHES OF RAIN SITTING  
AT LESS THAN 40 PERCENT.  
 
THE POTENTIAL FOR AIR QUALITY ISSUES REMAIN A CONCERN AS THE  
PATTERN GOES UNCHANGED AND CAN STILL DRAW WILDFIRE SMOKE TO THE  
REGION. PLEASE SEE YOUR LOCAL DEP FOR THE LATEST INFORMATION AND  
AIR QUALITY ALERTS FOR YOU AREA.  
 

 
   
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/
 
 
SUBSIDENCE AND SFC RIDGING WILL RETURN DRY WEATHER FORECASTS TO  
THE REGION FRIDAY NIGHT INTO SATURDAY AS THE NEW ENGLAND LOW  
FINALLY BEGINS TO SHIFT EAST. RISING PRESSURE HEIGHTS ALOFT AS  
NORTHWEST FLOW WEAKENS IN RESPONSE TO THE DEPARTING LOW WILL  
PROMOTE TEMPERATURE MODERATION AS WELL FOR SATURDAY. EXPECT MORE  
SEASONABLE AFTERNOON TEMPERATURE AMID INCREASED INSOLATION. THIS  
PATTERN SHIFT WILL ALSO SERVE TO CUT OFF THE WILDFIRE SMOKE  
FETCH AND LIKELY END THE CURRENT STRING OF DAYS WITH AIR QUALITY  
ISSUES.  
 
QUASI-ZONAL FLOW WILL DEVELOP BY SATURDAY NIGHT OVER THE REGION  
AS A DEVELOPING TROUGH/LOW DEEPENS OVER THE NORTHERN MISSISSIPPI  
RIVER VALLEY. A STREAM OF CIRRUS CONNECTED TO WARM/MOIST  
ADVECTION ALOFT IN ADVANCE OF THIS SYSTEM WILL MOVE OVER THE  
FORECAST AREA, MODERATING OVERNIGHT TEMPERATURE TOWARDS  
SEASONABLE LEVELS.  
 

 
   
LONG TERM /SUNDAY THROUGH THURSDAY/
 
 
THE AFOREMENTIONED TROUGH IS EXPECT TO DROP OUT OF CENTRAL  
CANADA DURING THE DAY ON SATURDAY AND BECOME A DEEPENING WESTERN GREAT  
LAKES CUT OFF LOW ON SUNDAY. SOUTHWESTERLY FLOW AHEAD OF THE  
TROUGH AXIS WILL FOSTER WARM, MOIST ADVECTION SUNDAY AND RAISE  
AREA TEMPERATURE ABOVE NORMAL. AT THIS TIME, THE LOCATION OF  
THE LOW TO THE WEST SHOULD KEEP SUNDAY MOSTLY DRY, IN PART DUE  
TO WARM-AIR CAPPING ALOFT AND POSITIONING OF JET ASCENT. PRE-  
FRONTAL CONVERGENCE MAY RESULT IN A FEW SHOWERS OVERNIGHT  
SUNDAY, BUT THE SURFACE WARM AND COLD FRONT, ALONG WITH THE BEST  
CHANCES OF PRECIPITATION, ARE NOT EXPECTED TO CROSS UNTIL  
MONDAY. THIS TIMING FOLLOWS THE TREND OF SLOWER PROGRESSION OF  
THE UPPER AND SURFACE LOW. PROBABILISTIC QPF THROUGH 12Z TUESDAY  
RANGES FROM AROUND A THIRD OF AN INCH ON THE LOW END TO AROUND  
ONE AND A HALF INCHES ON THE HIGH END.  
 
THERE IS MODERATE CONFIDENCE THE UPPER LOW WILL SIT NEARBY  
THROUGH MID WEEK, INTRODUCING INTERMITTENT PRECIPITATION CHANCES  
WITH PASSING SHORTWAVES IN SOUTHWEST FLOW. THE UPPER LOW WILL  
LIKELY DEPART BY LATE WEEK.  
 

 
   
AVIATION /03Z FRIDAY THROUGH TUESDAY/
 
 
CLOUDS WILL CONTINUE TO FILTER THROUGH THE REGION OVERNIGHT AS  
MOISTURE WITHIN AN UPPER-LVL LOW REMAINS CENTERED OVER THE  
NORTHEAST. HOWEVER, VFR CONDITIONS WILL LIKELY PREVAIL WITH LITTLE  
MOISTURE IN THE BOUNDARY LAYER. HAZE, FROM WILDFIRE SMOKE DIRECTED  
SOUTH FROM QUEBEC, MAY LINGER ACROSS THE REGION BUT WILL LIKELY  
BE NO LOWER THAN 6SM.  
 
SHOWERS MAY DEVELOP FOR SITES EAST/SOUTHEAST OF PIT FRIDAY AFTERNOON  
(AFTER 18Z) WITH AN EMBEDDED SHORTWAVE WITHIN AN UPPER-LVL LOW.  
HOWEVER, IMPACTS TO ANY SITES WILL BE BRIEF; PROBABILITIES ARE  
HIGHER FOR PIT/AGC/MGW/LBE BETWEEN 18Z AND 23Z FOR SHOWER  
ACTIVITY.  
   
OUTLOOK
 
 
ANY LINGERING HAZE/SMOKE WILL LIKELY CLEAR FROM THE REGION SATURDAY  
WITH A CHANCE IN THE UPPER LEVEL PATTERN. RESTRICTIONS IN MUCH-  
NEEDED WIDESPREAD RAINFALL ARE POSSIBLE BY SUNDAY AND MONDAY.  
 

 
   
CLIMATE
 
 
PROLONGED DRY CONDITIONS HAVE RESULTED IS SIZABLE DRY STREAKS  
AT SOME OBSERVING SITES. THE LONGEST CONSECUTIVE DAYS WITHOUT  
MEASURABLE PRECIP AND CURRENT STREAKS ARE (AS OF JUNE 7TH):  
 
CLIMATE SITE RECORD STREAK CURRENT STREAK  
____________________________________________________________  
PITTSBURGH 26 DAYS, 1874 18 DAYS  
DUBOIS 23 DAYS, 1988 18 DAYS  
ZANESVILLE 44 DAYS, 1963 18 DAYS  
NEW PHILADELPHIA 27 DAYS, 1963 18 DAYS  
WHEELING 27 DAYS, 1947/1884 18 DAYS  
MORGANTOWN 36 DAYS, 1908 4 DAYS  
 

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

 
 

 
SYNOPSIS...MILCAREK  
NEAR TERM...FRAZIER  
SHORT TERM...FRAZIER  
LONG TERM...MILCAREK  
AVIATION...HEFFERAN/88  
CLIMATE...MILCAREK  
 
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