142  
FXUS61 KPHI 252336  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
636 PM EST SAT JAN 25 2020  
   
SYNOPSIS
 
 
INTENSIFYING LOW PRESSURE WILL MOVE NORTHEAST OF THE AREA THIS  
EVENING INTO SUNDAY AND A COLD FRONT WILL MOVE THROUGH OUR AREA  
THIS EVENING. A WEAK TROUGH SOUTH OF THE MAIN LOW WILL PASS NEAR  
THE REGION ON MONDAY. HIGH PRESSURE WILL THEN SLOWLY BUILD ACROSS  
THE EASTERN HALF OF THE US THROUGH THE REMAINDER OF THE WORKWEEK  
BEFORE ANOTHER AREA OF LOW PRESSURE APPROACHES NEXT WEEKEND.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
630 UPDATE: NO SIGNIFICANT CHANGES TO GOING FORECAST AS PRECIP  
HAS MOVED OUT OF THE AREA, AND THE BACK EDGE OF THE MAIN STRATUS  
DECK IS ALSO BEGINNING TO CLEAR THE FAR SW PART OF THE REGION.  
GENERALLY EXPECT THAT WESTERLY FLOW AND ASSOCIATED DRY AIR  
ADVECTION WILL BE STRONG ENOUGH TO PREVENT WIDESPREAD FOG  
DEVELOPMENT OVERNIGHT (DESPITE THE ANTECEDENT RAINFALL). THE  
LOCALLY DENSE DOG THAT HAS DEVELOPED OVER THE NORTHERN NJ  
COAST RECENTLY SHOULD THIN OUT SHORTLY AS WESTERLY WINDS PICK UP  
BEHIND THE DEPARTING LOW.  
 
PREVIOUS DISCUSSION:  
 
THE BACK EDGE OF THE MAIN BAND OF RAIN EXTENDED ACROSS THE NEW  
YORK METROPOLITAN AREA AROUND 3:00 PM. IT WILL CONTINUE TO LIFT  
NORTHEASTWARD, LEAVING CLOUDS AND SCATTERED SHOWERS IN ITS WAKE  
INTO THIS EVENING.  
 
A MID LEVEL LOW LOCATED OVER SOUTHEASTERN MICHIGAN THIS AFTERNOON,  
WILL PROGRESS EASTWARD. THE FEATURE SHOULD PASS OVER SOUTHERN  
ONTARIO AND LAKE ONTARIO TONIGHT. THE LOW IS EXPECTED TO PULL A  
SHORT WAVE TROUGH OVER OUR REGION THIS EVENING, BRINGING AN END TO  
ANY LINGERING SHOWERS.  
 
SURFACE LOW PRESSURE CENTERED NEAR PHILADELPHIA AT MID AFTERNOON IS  
FORECAST TO DRIFT NORTHEASTWARD, REACHING NEW ENGLAND TONIGHT.  
 
A LIGHT WEST WIND WILL DEVELOP FOR TONIGHT, BRINGING DRY AIR INTO  
OUR REGION. AS A RESULT, WE ARE ANTICIPATING A DECREASE IN CLOUD  
COVER FOR TONIGHT. LOW TEMPERATURES SHOULD FAVOR THE LOWER AND  
MIDDLE 30S IN OUR COUNTIES IN EASTERN PENNSYLVANIA, NEW JERSEY,  
DELAWARE AND NORTHEASTERN MARYLAND.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/
 
 
THE MID LEVEL LOW IS FORECAST TO MOVE ACROSS THE ADIRONDACKS,  
NORTHERN NEW ENGLAND AND SOUTHERN QUEBEC ON SUNDAY. THE FEATURE IS  
EXPECTED TO PULL A COUPLE WEAK SHORT WAVE TROUGHS OVER OUR REGION ON  
SUNDAY. AS A RESULT, WE SHOULD SEE AN INCREASE IN STRATOCUMULUS  
DURING THE DAYLIGHT HOURS. HIGHS SHOULD FAVOR THE 40S WITH A WEST  
WIND AROUND 10 MPH.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
 
 
SUMMARY: IT WILL BE A RELATIVELY UNEVENTFUL END OF JANUARY AS A  
GENERALLY DRY AND SEASONABLE NORTHWEST FLOW ALOFT PREVAILS FOR  
THE BULK OF THE WORK-WEEK WITH ONLY A FEW LOW-AMPLITUDE AND  
MOISTURE-STARVED DISTURBANCES PASSING THROUGH. A STRONGER AND  
MORE ORGANIZED STORM SYSTEM MAY APPROACH THE AREA NEXT WEEKEND,  
BUT DETAILS ARE LACKING AT THIS POINT.  
 
DETAILS:  
 
MONDAY/TUESDAY: THE SECONDARY LOW WHICH PASSED THROUGH THE AREA  
TODAY WILL ULTIMATELY STRENGTHEN AND MERGE WITH THE PRIMARY  
GREAT LAKES LOW BY SUNDAY NIGHT (OVER NEW BRUNSWICK). A BACK-  
SIDE MID-LVL SHORTWAVE WILL SLIDE THROUGH THE AREA ON MONDAY  
WITH A WEAK SFC.TROUGH EXTENDING FROM THE LARGER LOW TO OUR  
NORTH. GIVEN WEAK FORCING AND LIMITED MOISTURE DO NOT EXPECT  
MUCH PRECIPITATION OUTSIDE OF POSSIBLY SOME SNOW  
SHOWERS/FLURRIES OVER THE FAR NORTH, ALTHOUGH THERE COULD BE  
LOCALLY THICK STRATOCUMULUS AT TIMES (PARTICULARLY OVER THE  
NORTHERN HALF OF THE AREA IN THE AFTERNOON). TUESDAY WILL BE  
LARGELY UNEVENTFUL ALTHOUGH A DRY COLD FRONT DOES LOOK TO PUSH  
IN LATE IN THE DAY. TEMPERATURES WILL GENERALLY BE ABOUT 5  
DEGREES ABOVE NORMAL ON MONDAY, AND WILL COOL SLIGHTLY TO A  
COUPLE DEGREES ABOVE CLIMO ON TUESDAY.  
 
WEDNESDAY-FRIDAY. QUIET AND DRY AS HIGH PRESSURE INITIALLY  
CENTERED OVER CENTRAL ONTARIO BUILDS SE OVER THE REGION.  
TEMPERATURES WILL BE SEASONABLE THROUGH THE PERIOD WITH HIGHS  
GENERALLY IN THE UPPER 30S TO LOW 40S WED/THURS. THE HIGH MAY  
MOVE OFFSHORE BY FRIDAY WITH SOME RETURN FLOW DEVELOPING SO  
FRIDAY COULD BE A BIT WARMER.  
 
SATURDAY AND BEYOND. A STORM SYSTEM LOOKS TO APPROACH (POSSIBLY  
TAKING THE FORM OF A COASTAL LOW) NEXT WEEKEND BUT DETAILS  
REGARDING THE TRACK AND ASSOCIATED PRECIPITATION AND THERMAL  
FIELDS ARE UNKNOWN AT THIS TIME. LEFT POPS IN THE CHC.RANGE DUE  
TO TIMING UNCERTAINTIES.  
 

 
   
AVIATION /23Z SATURDAY THROUGH THURSDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
THIS EVENING...MVFR AND IFR CEILINGS GRADUALLY IMPROVING TO VFR.  
THE WIND SHOULD SETTLE INTO THE WEST AROUND 10 KNOTS. MEDIUM  
CONFIDENCE.  
 
OVERNIGHT...VFR WITH DECREASING CLOUD COVER. WEST TO NORTHWEST WIND  
5 TO 10 KNOTS. MEDIUM CONFIDENCE.  
 
SUNDAY...VFR CEILINGS. WEST WIND INCREASING AROUND 10 KNOTS WITH  
GUSTS NEAR 20 KNOTS. HIGH CONFIDENCE.  
 
OUTLOOK...  
 
SUNDAY NIGHT-TUESDAY...MAINLY VFR, THOUGH CIGS COULD  
OCCASIONALLY APPROACH MVFR AT TIMES DUE TO STRATOCUMULUS. WINDS  
REMAIN WEST TO NORTHWEST AND MAY GUST UP TO 20 KNOTS AT TIMES  
DURING THE DAYTIME HOURS. MODERATE CONFIDENCE.  
 
WEDNESDAY/THURSDAY...MAINLY VFR WITH NW WINDS 5-10 KNOTS ON WED,  
AND N WINDS 5 KTS OR LESS ON THURSDAY..  
 

 
   
MARINE
 
 
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE COASTAL WATERS  
THROUGH SUNDAY AFTERNOON AS DECAYING LOW PRESSURE OVER SOUTHERN  
QUEBEC SLOWLY DRIFTS EAST. WIND GUSTS WILL STAY CLOSE TO OUR JUST  
BELOW 25 KTS SUNDAY NIGHT WITH THE SCA POSSIBLY NEEDING TO BE  
EXTENDED THROUGH THE NIGHT.  
 
OUTLOOK...  
 
MONDAY... WINDS AND WAVES WILL SLOWLY RELAX THROUGH THE DAY MONDAY  
AS THE PRESSURE GRADIENT WEAKENS.  
 
TUESDAY THROUGH THURSDAY... WINDS AND WAVES WILL REMAIN BELOW  
ADVISORY LEVELS THROUGH THE PERIOD.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ450>455.  
 

 
 

 
SYNOPSIS...CARR  
NEAR TERM...CARR/IOVINO  
SHORT TERM...IOVINO  
LONG TERM...CARR  
AVIATION...CARR/IOVINO  
MARINE...HAINES  
 
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