916  
FXUS61 KCTP 181128  
AFDCTP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE STATE COLLEGE PA  
728 AM EDT MON OCT 18 2021  
   
SYNOPSIS
 
 
COOL NORTHWEST FLOW OFF OF THE WARMER GREAT LAKES COULD BRING  
MORE LIGHT SHOWERS TO PARTS OF THE ALLEGHENIES AND CENTRAL  
MOUNTAINS TODAY, WITH MAINLY FAIR WEATHER ELSEWHERE. DRY  
CONDITIONS WILL FOLLOW ON TUESDAY, WITH A MODERATING TREND IN  
TEMPERATURES THROUGH MID WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
LAKE EFFECT DECREASING EARLY THIS MORNING BUT QUASISTATIONARY  
5H SHEAR AXIS STILL EXTENDS FROM EASTERN ONTARIO TO SOUTHEAST  
PA AND COUPLED NW BOUNDARY LAYER FLOW. EXPECT A LULL IN SHOWER  
ACTIVITY THROUGH LATE MORNING WITH ISOLD TO SCT SPRINKLES MAINLY  
NORTH OF I80 BEFORE AFOREMENTIONED SHEAR AXIS BUCKLES YET AGAIN  
BY THIS AFTERNOON. COOLING TEMPS ALOFT ASSOCIATED WITH THE  
SHEAR AXIS ALOFT ALONG WITH WARMING IN THE 700-500 MB LAYER WILL  
PRODUCE ENOUGH INSTABILITY TO SUPPORT CONSIDERABLE BROKEN  
CLOUDS AND ADDITIONAL SCATTERED SPRINKLES ACROSS THE NORTHERN  
MTNS AND PERHAPS THE LAUREL HIGHLANDS. ELSEWHERE, ACROSS THE  
RIDGE AND VALLEY REGION OF THE STATE, INCREASING AMOUNTS OF  
SUNSHINE ARE EXPECTED FROM SOUTH TO NORTH.  
 
HIGHS WILL RANGE FROM NEAR 50F OVER THE NORTHERN MOUNTAINS, TO  
THE LOWER 60S IN THE LOWER SUSQUEHANNA VALLEY.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/
 
 
MAINLY CLEAR SKIES ARE EXPECTED TONIGHT AND TUESDAY ACROSS THE  
SOUTHEAST HALF OF CENTRAL PA AS A LARGE RIDGE OF HIGH PRESSURE  
AT THE SFC AND ALOFT BUILDS IN FROM THE MIDWEST. DECREASING  
CLOUDS WILL BE SEEN OVER THE NW HALF AS HEIGHTS RISE AND  
BOUNDARY LAYER WARMS, DESPITE CONTINUED NORTHWEST FLOW.  
 
LOWS TONIGHT WILL BE CHILLY, RANGING FROM THE MID TO UPPER 30S  
OVER NORMALLY COLDER AREAS OF THE NORTHERN TIER, TO THE 40S  
ELSEWHERE. TUESDAY AFTERNOON WILL BE NOTICEABLY WARMER, WITH  
HIGHS RANGING IN THE 60S AREA-WIDE, PERHAPS TOUCHING 70 FOR SOME  
IN THE SUSQUEHANNA VALLEY.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
 
 
HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH THE MIDDLE OF  
WEEK, PRODUCING DRY WEATHER AND MODERATING TEMPERATURES. ANOTHER  
TROUGH AND ASSOCIATED SFC COLD FRONT WILL APPROACH THE AREA ON  
THURSDAY, PROVIDING OUR NEXT CHANCE OF SHOWERS/STORMS AND GUSTY  
WINDS. A RETURN TO COOLER TEMPERATURES IS EXPECTED LATE NEXT  
WEEK, BEHIND THE FRONT.  
 
AFTER THAT, IT LOOKS LIKE GENERAL UPPER-LEVEL TROUGHINESS WILL  
BE IN PLACE OVER THE NORTHEASTERN U.S. INTO NEXT WEEKEND, WITH  
THE POTENTIAL FOR A REINFORCING SHOT OF SEASONABLY COOL AIR AND  
LAKE EFFECT RAIN SHOWERS. LOW TEMPS SAT NIGHT AND SUN NIGHT ARE  
PROGGED TO BE THE COLDEST YET THIS SEASON - WITH WIDESPREAD LOWS  
IN THE 30S POSSIBLE SUN NIGHT IF WINDS ARE LIGHT AND WE END UP  
UNDER THE CORE OF THE HIGH PRESSURE SYSTEM. BELIEVE IT OR NOT,  
THAT'S JUST A COUPLE DEGREES BELOW AVERAGE.  
 

 
   
AVIATION /12Z MONDAY THROUGH FRIDAY/
 
 
GUSTY NORTHWEST FLOW WILL RAMP BACK UP TODAY AS VFR CONDITIONS  
PREVAIL AREAWIDE. A SCT TO BKN DECK WILL ADVECT OVER THE CENTRAL  
MOUNTAINS THIS AFTERNOON AS LAKE-ENHANCED CLOUDS AND A FEW  
SCATTERED SHOWERS MOVE THROUGH THE AREA.  
 
OVERNIGHT, CLEAR SKIES ARE FORECAST AS HIGH PRESSURE MOVES  
CLOSER TO PA. AS SUCH, WINDS WILL GO CALM AT THE SURFACE AND  
LLWS WILL BE A CONCERN ONCE AGAIN OVERNIGHT WITH 30 TO 35KT  
WINDS AT ABOUT 2KFT AGL. SOME FOG DEVELOPMENT IS POSSIBLE IN  
THE VALLEYS NEAR BFD EARLY TUESDAY MORNING.  
 
OUTLOOK...  
 
TUE-WED...GENERALLY VFR.  
 
THU...RESTRICTIONS POSSIBLE LATE IN SHRA WITH COLD FRONTAL  
PASSAGE.  
 
FRI...LINGERING MVFR CIGS N/W. BECOMING VFR ELSEWHERE.  
 

 
   
CLIMATE
 
 
THE FIRST HALF OF OCTOBER HAS SEEN RECORD-SETTING PERSISTENTLY-  
WARM TEMPERATURES, PARTICULARLY DURING THE OVERNIGHT HOURS.  
HERE ARE THE AVERAGE MONTH- TO- DATE TEMPERATURES AT SITES  
AROUND CENTRAL PENNSYLVANIA FOR THE PERIOD OF OCTOBER 1 -  
OCTOBER 16, 2021 AND WHERE 2021 RANKS:  
 
SITE MEAN AVERAGE 2021 MEAN MINIMUM 2021  
TEMPERATURE RANK TEMPERATURE RANK  
ALTOONA 64.0 2ND 55.4 2ND  
BRADFORD 62.3 1ST 53.6 1ST  
HARRISBURG 67.0 1ST 59.6 1ST  
STATE COLLEGE 64.4 1ST 56.3 1ST  
WILLIAMSPORT 64.8 1ST 57.1 1ST  
 

 
   
CTP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
SYNOPSIS...DEVOIR  
NEAR TERM...LAMBERT/DEVOIR  
SHORT TERM...JUREWICZ/DEVOIR  
LONG TERM...EVANEGO/COLBERT  
AVIATION...COLBERT/BANGHOFF  
CLIMATE...BANGHOFF  
 
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