567
FXUS61 KPHI 200908
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
408 AM EST THU FEB 20 2020
SYNOPSIS
HIGH PRESSURE LOCATED OVER THE UPPER MIDWEST WILL CONTINUE TO
SLOWLY SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS, WITH THE CENTER
OF THE HIGH FINALLY PASSING OFF THE CAROLINA COAST ON SUNDAY.
LOW PRESSURE IS EXPECTED TO PROGRESS FROM THE MIDDLE MISSISSIPPI
RIVER VALLEY ON MONDAY TO THE NORTHEASTERN STATES ON TUESDAY.
ANOTHER AREA OF LOW PRESSURE MAY TRAIL BEHIND THIS LOW AND
IMPACT THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
NEAR TERM / THROUGH MIDNIGHT/
THE MAIN INFLUENCE ON OUR WEATHER THE NEXT FEW DAYS WILL BE THE
AREA OF STRONG HIGH PRESSURE CURRENTLY CENTERED OVER THE UPPER
MIDWEST. COOL NORTHERLY FLOW WILL PREVAIL ON THE EASTERN
PERIPHERY OF THIS FEATURE TODAY, AND HIGHS ARE EXPECTED TO BE
AROUND 5-10 DEGREES BELOW NORMAL (E.G. MOSTLY UPPER 30S TO LOWER
40S). THE UPPER-LVL JET AXIS WILL PIVOT OVERHEAD TODAY WHICH
SHOULD SUPPORT A STEADY STREAM OF MID-HIGH CLOUDS.
ALTHOUGH THE VAST MAJORITY OF THE AREA SHOULD REMAIN DRY DUE TO
THE INFLUENCE OF THE AFOREMENTIONED HIGH THERE ARE TWO POTENTIAL
AREAS THAT MAY SEE PRECIPITATION LATER THIS AFTERNOON INTO THIS
EVENING. THE FIRST (AND MORE LIKELY) OF THESE AREAS IS SOUTHERN
DELMARVA AND FAR SOUTHERN NJ, WHERE THE NORTHERN FRINGE OF THE
MOISTURE ENVELOPE ASSOCIATED WITH A STRENGTHENING LOW OFF THE NC
COAST WILL ENCROACH UPON OUR "DRY BUBBLE". GENERALLY THINK THE
HIGH WILL WIN OUT AND KEEP ANY SIGNIFICANT PRECIPITATION SHUNTED
TO OUR SOUTH. THAT BEING SAID DUE TO THE COOL AND DRY AIRMASS
IF PRECIPITATION IS ABLE TO FALL IT WOULD LIKELY COME IN THE
FORM OF SNOW, AND CAN'T RULE OUT A DUSTING TO A FEW TENTHS OVER
THE FAR SOUTH THIS AFTERNOON INTO THIS EVENING IF THINGS
OVER-PERFORM RELATIVE TO CURRENT EXPECTATIONS.
THE SECOND POTENTIAL AREA OF PRECIPITATION (IN THE FORM OF
FLURRIES OR LIGHT SNOW SHOWERS) WOULD BE IN FAR NORTHERN AND
WESTERN PORTIONS OF OUR AREA IN ASSOCIATION WITH A COLD FRONT
AND APPROACHING SHORTWAVE LATE THIS AFTERNOON. SINCE IT WILL BE
EVEN DRIER RELATIVE TO DELMARVA GENERALLY DON'T HAVE HIGH
EXPECTATIONS THAT MEASURABLE SNOWFALL WILL OCCUR WITH THIS
FRONT, AND CONSEQUENTLY LEFT MOST AREAS WITH NON-MENTIONABLE
POPS OUTSIDE OF THE POCONOS AND WESTERN BERKS COUNTY.
SHORT TERM /TONIGHT/
THE COLD FRONT WILL CONTINUE TO PUSH THROUGH THE REGION FOR THE
FIRST HALF OF THE OVERNIGHT PERIOD, WHILE THE APPROACHING
SHORTWAVE SHOULD BEGIN TO LIFT THE LOW TO OUR SOUTH OUT TO SEA.
DRIER AIR FILTERING IN BEHIND THE FRONT SHOULD RESULT IN
CLEARING SKIES FROM N-S WITH MOSTLY CLEAR SKIES EXPECTED BY
FRIDAY MORNING. ANY LIGHT PRECIPITATION EITHER ASSOCIATED WITH
THE FRONT OR THE SOUTHERN LOW SHOULD CLEAR THE AREA BY MIDNIGHT.
OVERNIGHT LOWS WILL BE A BIT CHALLENGING AS THIS WILL BE A
SITUATION WHERE THE WINDS WILL REMAIN SOMEWHAT ELEVATED BEHIND
THE FRONT, BUT AT THE SAME TIME THERE WILL BE FAIRLY STRONG COLD
ADVECTION. CONSEQUENTLY WENT TOWARDS THE MEAN OF GUIDANCE WHICH
RESULTS IN A FAIRLY COOL NIGHT WITH LOWS BOTTOMING OUT IN THE
UPPER TEENS TO LOWER 20S BY FRIDAY MORNING, BUT TEMPERATURES
COULD BE LOCALLY COLDER IN PRONE SPOTS (E.G. PINE BARRENS, PA
VALLEYS) IF WE DECOUPLE.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
FRIDAY THROUGH SUNDAY...THE START OF THE EXTENDED WILL BE QUITE
UNEVENTFUL AS THE EXPANSIVE CENTRAL US HIGH VERY SLOWLY DRIFTS
SOUTHEASTWARDS AND ALSO WEAKENS. AT UPPER LEVELS THE AREA WILL
REMAIN DISPLACED FROM BOTH THE SOUTHERN AND NORTHERN STREAMS
WHICH WILL FURTHER SUPPORT THE TRANQUIL WEATHER... AND EVEN
CLOUDS WILL BE HARD TO COME BY.
FRIDAY WILL REMAIN ON THE COOL SIDE WITH HIGHS GENERALLY ONLY IN
THE MID TO UPPER 30S BUT WE WILL BEGIN TO WARM UP QUICKLY OVER
THE WEEKEND AS THE LOW-LVL FLOW BACKS TO MORE WESTERLY AND THEN
SOUTHWESTERLY. SATURDAY'S HIGHS SHOULD BE IN THE UPPER 40S TO
LOWER 50S, WHILE SUNDAY'S HIGHS WILL GENERALLY BE IN THE LOW TO
MID 50S. THESE TEMPERATURES COMBINED WITH ABUNDANT SUNSHINE
SHOULD MAKE FOR A VERY NICE WEEKEND.
MONDAY THROUGH WEDNESDAY... THE HIGH WILL HAVE FINALLY SHIFTED
OFFSHORE BY MONDAY AND SOME MOISTURE WILL START TO RETURN AS
SOUTHERLY FLOW INCREASES. GUIDANCE HAS SLOWED A BIT WITH THE
ARRIVAL OF THE NEXT STORM SYSTEM (WITH SOME LINGERING DISCREPANCIES
AMONG INDIVIDUAL MODELS), DELAYING IT UNTIL MONDAY NIGHT OR
TUESDAY. THE THERMAL PROFILES DO NOT SUPPORT MUCH CHANCE OF
SIGNIFICANT WINTRY PRECIPITATION WITH THIS SYSTEM SO AT THE
MOMENT THINK THIS WILL BE PRIMARILY A RAIN EVENT (WITH THE MOST
LIKELY TIME FOR STEADY RAIN BEING TUESDAY). THERE IS THE
POTENTIAL FOR A SECONDARY SYSTEM WEDNESDAY INTO THURSDAY OF NEXT
WEEK BUT DETAILS ARE LACKING AT THIS TIME.
TEMPERATURES WILL LIKELY BE QUITE WARM ON MONDAY AND TUESDAY
WITH HIGHS GENERALLY IN THE 50S (WITH SOME POTENTIAL FOR 60S
EVEN), BEFORE COOLING OFF A BIT ON WEDNESDAY BEHIND THE COLD
FRONT. OF NOTE THERE IS A PRETTY STRONG SIGNAL IN THE ENSEMBLE
GUIDANCE FOR A PERIOD OF COLDER TEMPERATURES LATE NEXT WEEK BUT
SPECIFIC DETAILS ARE NATURALLY LACKING.
AVIATION /08Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR CONDITIONS EXPECTED WITH MID AND HIGH CLOUDS
EARLY, WITH SOME LOWER CEILINGS (BUT STILL VFR) MOVING IN LATE
THIS AFTERNOON. WINDS WILL GENERALLY BE NW-N AROUND 5 KTS. HIGH
CONFIDENCE.
TONIGHT... VFR WITH CEILINGS CLEARING OUT THROUGH THE FIRST HALF
OF THE NIGHT. N/NE WINDS AROUND 10-15 KTS EXPECTED.
OUTLOOK...
FRIDAY-SUNDAY...VFR WITH NORTH-NORTHWEST WINDS 5 TO 10 KNOTS
FRIDAY BECOMING WESTERLY 10 KTS ON SATURDAY, AND THEN
SOUTHWESTERLY 5-10 KTS ON SUNDAY. WINDS MAY BECOME LIGHT AND
VARIABLE OVERNIGHT EACH DAY. HIGH CONFIDENCE.
MONDAY...MAINLY VFR. A CHANCE OF RAIN IN THE AFTERNOON. SOUTH
WIND 5 TO 10 KNOTS. HIGH CONFIDENCE.
MARINE
SEAS WILL GENERALLY BE 2 FT OR LESS THROUGH MOST OF THE DAY
TODAY WITH NORTHERLY WINDS 5-10 KTS AND GUSTS 10-15KTS.
BEHIND A COLD FRONT THIS EVENING NORTHERLY WINDS SHOULD INCREASE
TO SUSTAINED 20-25 KTS WITH GUSTS UP TO 30KTS WHILE SEAS WILL
INCREASE TO 4-6 FT BY FRIDAY MORNING. SOME SNOW SHOWERS WILL BE
POSSIBLE LATE THIS AFTERNOON INTO THIS EVENING ACROSS THE FAR
SOUTHERN WATERS.
OUTLOOK...
FRIDAY...SCA CONDITIONS ARE EXPECTED THROUGH THE EARLY
AFTERNOON FRIDAY AFTER WHICH TIME WINDS AND SEAS SHOULD DIP
BELOW SCA CRITERIA.
FRIDAY NIGHT THROUGH MONDAY...SUB-SCA CONDITIONS EXPECTED
THROUGH THE PERIOD WITH SEAS GENERALLY RUNNING 2-3 FT AND GUSTS
20 KTS OR LESS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST FRIDAY
FOR ANZ452>455.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST FRIDAY
FOR ANZ430-431-450-451.
SYNOPSIS...CARR
NEAR TERM...CARR
SHORT TERM...CARR
LONG TERM...CARR
AVIATION...CARR
MARINE...CARR
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