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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