FXUS61 KPHI 062159 CCA
AFDPHI
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
458 PM EST SUN DEC 6 2009
.SYNOPSIS...
HIGH PRESSURE WILL CONTROL THE WEATHER THROUGH TUESDAY EVEN THOUGH
A DRY COLD FRONT WILL MOVE THROUGH THE REGION MONDAY NIGHT.
A LOW PRESSURE SYSTEM WILL MOVE OUT TO THE MISSOURI VALLEY AND
WILL AFFECT THE REGION TUESDAY NIGHT AND WEDNESDAY. HIGH
PRESSURE WILL BUILD IN FROM THE WEST LATE NEXT WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
SOME HIGH CLOUDS CAUGHT UP IN THE JET STREAM WILL MOVE ACROSS THE
AREA TONIGHT. WITH HIGH PRESSURE IN PLACE, WINDS WILL BE LIGHT AND
VARIABLE. THIS WILL LET TEMPERATURES DROP OFF TO NEAR THE
DEWPOINTS N/W OF PHL AND LOWS IN THIS AREA SHOULD RANGE FROM THE
UPPER TEENS IN THE POCONOS TO MID 20S IN THE N/W SUBURBS. FARTHER
SOUTH AND EAST WHERE SNOW COVER IS LACKING, MET TEMPS LOOK
REASONABLE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
HIGH PRESSURE WILL PREVAIL MONDAY AND TUESDAY, EVEN THOUGH A DRY
COLD FRONT WILL MOVE THROUGH FROM THE NORTHWEST MONDAY NIGHT. THE
ONLY EFFECT THE COLD FRONT SHOULD HAVE IS TO KEEP TEMPERATURES
TUESDAY FROM GETTING MUCH HIGHER THAN MONDAY. SKIES SHOULD BE
PARTLY CLOUDY DUE TO SOME MID AND HIGH CLOUDS CAUGHT UP WITH THE
JET STREAM ALOFT.
TUESDAY NIGHT...LOW PRESSURE OVER THE MISSOURI VALLEY TUESDAY
AFTERNOON WILL HEAD NORTHEAST TO THE GREAT LAKES THROUGH WEDNESDAY
AS A SECONDARY LOW FORMS OFF THE COAST. EVEN WITH THE SECONDARY
LOW OFF THE COAST, THE LOW TO THE WEST WILL BE THE DOMINANT
FEATURE. THE FLOW AROUND THE LOW WILL BRING MILDER AIR NORTH INTO
THE REGION. HOWEVER, OLD HIGH PRESSURE OVER NEW ENGLAND WILL BE
SLOW TO MOVE AWAY. THEREFORE, I EXPECTED TRAPPED COLD AIR TO
LINGER TO THE N/W OF PHL AND WITH MOISTURE MOVING IN FROM THE
SOUTH, SOME SNOW IS EXPECTED BEFORE ANY CHANGEOVER TO RAIN. IF
SURFACE TEMPS DONT GET ABOVE FREEZING, SOME FREEZING RAIN IS
POSSIBLE, BUT AT THIS POINT THE CHANCES ARE NOT HIGH ENOUGH TO
INCLUDE IN THE FCST. FROM PHL S/E, ENOUGH WARMER AIR SHOULD MOVE IN
FROM THE OCEAN TO KEEP ALL PCPN RAIN.
FCST TEMPS THROUGH TUESDAY WERE GENERALLY A BLEND OF MET/MAV.
TEMPS SHOULD RISE TUESDAY NIGHT. ON WEDNESDAY, ONCE THE TRAILING
COLD FRONT FROM THE LOW MOVES THROUGH, ANY LINGERING COLD AIR AT
THE SURFACE WILL BE SCOURED OUT BEFORE A NEW COLD AIR MASS MOVES
IN FROM THE WEST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LOW PRESSURE WILL PULL AWAY WITH ONLY SOME LINGERING LIGHT SHOWERS
AROUND WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BEGIN TO BUILD IN
FOR THURSDAY AND LAST THROUGH THE REST OF THE WEEK.
ANOTHER SYSTEM MAY FORM OFF OF THE SOUTHEASTERN US COAST LATE IN THE
WEEK AND MOVE NORTHEASTWARD ON SATURDAY. HOWEVER, AT THIS TIME THE
LOW LOOKS TO REMAIN OFFSHORE AND CONFIDENCE IS NOT HIGH THAT WE WILL
SEE MUCH PRECIPITATION SATURDAY NIGHT. WE CONTINUE TO MENTION AT
LEAST A SLIGHT CHANCE FOR PRECIPITATION SATURDAY NIGHT, WHICH ONCE
AGAIN MAY BE A MIX OF RAIN AND SNOW IN PARTS OF THE REGION. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR SUNDAY.
TEMPERATURES ARE EXPECTED TO BE NEAR TO BELOW NORMAL THROUGH THE
PERIOD.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A VFR FORECAST IS EXPECTED THE REST OF TODAY INTO MONDAY. THIS
AFTERNOON, SOME SCT-BKN SC CLOUDS ARE MOVING SE ACROSS ERN PA AND
SRN NJ. A LIGHT TO MODERATE NW WIND IS OCCASIONALLY GUSTING TO NEAR
20 KTS. WINDS SHOULD DECREASE THIS EVENING AS HIGH PRESSURE BUILDS
OVERHEAD. CI/AC CLOUDS ARE SHOWN BY BOTH NAM/GFS MODEL SOUNDINGS FOR
LATER TONIGHT AND MONDAY. SATELLITE PICS SHOW THESE CLOUDS BEHIND
THE SUBTLE H5 RIDGE AXIS WHICH WILL CROSS THE AREA LATER TONIGHT..SO
SOME SCT-BKN SKY COVER WAS ADDED. WINDS WILL BE L/V TONIGHT AND
LIGHT FROM THE SOUTH MON MORNING.
OUTLOOK...
HIGH PRESSURE WILL CONTINUE TO SLIDE TO OUR EAST ON MONDAY, THEN A
WEAK FRONTAL BOUNDARY MAY MOVE THROUGH MONDAY NIGHT. AN INCREASE IN
/VFR/ CLOUDS IS EXPECTED WITH A RATHER LOW CHANCE OF PRECIPITATION
AS OF NOW. THE NEXT STORM SYSTEM, A POTENTIALLY SIGNIFICANT ONE, IS
FORECAST TO ARRIVE LATE TUESDAY NIGHT AND CONTINUE WEDNESDAY. THIS
MAY BRING A PERIOD OF HEAVIER RAIN AND WINDY CONDITIONS, ALTHOUGH
PERHAPS SOME SNOW OR MIXED PRECIPITATION OCCURS AT THE ONSET AT
KRDG, KABE AND KTTN. CLEARING ARRIVES THURSDAY ALTHOUGH A GUSTY
NORTHWESTERLY WIND WILL OCCUR IN THE WAKE OF THE STORM.
&&
.MARINE...
SEAS HAVE FALLEN BELOW 5 FT AT BUOY 44009 AND WITH HIGH PRESSURE
MOVING IN THEY SHOULD CONTINUE TO DECREASE THROUGH THIS EVENING.
WE HAVE THEREFORE DECIDED TO DROP THE SCA FROM THE COASTAL WATERS.
THE HIGH PRESSURE THEN SLIDES TO OUR EAST MONDAY WITH THE WINDS
SHIFTING TO A SOUTHERLY DIRECTION. A WEAK FRONTAL BOUNDARY LOOKS TO
MOVE THROUGH MONDAY NIGHT WITH MAINLY JUST A WIND SHIFT TO THE WEST
AND NORTHWEST EXPECTED. THIS FEATURE LOOKS TO BE ON THE WEAK SIDE,
THEREFORE CONDITIONS ARE FORECAST TO REMAIN BELOW ADVISORY CRITERIA.
AS HIGH PRESSURE BUILDS INTO THE NORTHEAST LATE TUESDAY, A POWERFUL
STORM IS FORECAST TO DEVELOP IN THE CENTRAL PLAINS. THIS STORM WILL
INTENSIFY FURTHER AS IT TRACKS INTO THE GREAT LAKES REGION WEDNESDAY
THEN TO OUR NORTH WEDNESDAY NIGHT INTO THURSDAY. THERE IS THE
POTENTIAL FOR A SECONDARY SURFACE LOW TO DEVELOP NEAR OUR COAST
WEDNESDAY. THE WINDS ARE EXPECTED TO INCREASE, ALTHOUGH IF THE
SECONDARY LOW DOES INDEED DEVELOP AND IS OVER OUR AREA, THE WINDS
MAY BE LIGHTER FOR A TIME. OVERALL, WINDS FROM THE EAST THEN
SOUTHEAST ARE FORECAST TO INCREASE WEDNESDAY, WITH AN EVENTUAL SHIFT
TO THE SOUTH AND SOUTHWEST. THERE IS WARMER AIR FORECAST TO SURGE
NORTHWARD AHEAD OF THE SYSTEM, THEREFORE THAT WOULD HINDER DEEPER
VERTICAL MIXING. FOLLOWING THE FRONTAL PASSAGE WEDNESDAY NIGHT,
COLDER AIR ARRIVING WILL ALLOW DEEPER MIXING TO OCCUR. WINDS ARE
EXPECTED TO REACH ADVISORY LEVELS AND POSSIBLY EVEN GALE FORCE
THROUGH THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...STAUBER
SHORT TERM...STAUBER
LONG TERM...MEOLA
AVIATION...O'HARA
MARINE...MEOLA/O'HARA
