Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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073 FXUS61 KPHI 062048 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 348 PM EST SAT FEB 6 2016 .SYNOPSIS... LOW PRESSURE IS FORECAST TO DEVELOP OFF THE SOUTHEAST COAST THIS WEEKEND AND TRACK NORTHEASTWARD LATE SUNDAY INTO MONDAY. ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP IN ITS WAKE NEAR THE MID- ATLANTIC COAST MONDAY NIGHT INTO TUESDAY. ARCTIC HIGH PRESSURE IS THEN EXPECTED TO BUILD IN FROM THE NORTH AND WEST DURING THE LATTER PART OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... HIGH PRESSURE REMAINS ACROSS THE AREA TONIGHT, WHICH WILL KEEP THE WEATHER DRY. OTHER THAN SOME CIRRUS CLOUDS, NOT MUCH TO AFFECT THE AREA. WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT. THIS WILL ALLOW FOR TEMPERATURES TO FALL OVERNIGHT AND COOL QUITE EFFICIENTLY. SHOULD BE ANOTHER FROSTY MORNING SUNDAY. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... AFTER ANOTHER FROSTY START, TEMPERATURES WILL RISE SEVERAL DEGREES WARMER THAN SATURDAY AND END UP A FEW DEGREES ABOVE NORMAL. CLOUDS WILL BEGIN TO THICKEN AND LOWER DURING THE AFTERNOON FROM SOUTH TO NORTH AS A SYSTEM APPROACHES FROM THE SOUTH. HOWEVER, WE EXPECT THE FORECAST TO REMAIN PRECIPITATION FREE THROUGH THE DAYTIME HOURS. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
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THERE ARE 2 SYSTEMS TO WATCH DURG THE EXTENDD PD. THE FIRST IS A STRONG CSTL LOW THAT EMERGES OFF THE SERN CST ON SUN. THE VAST MAJORITY OF THE MDL GUID KEEPS THIS LOW OFF THE ATLC CST, WITH MINIMAL IMPACT ON OUR AREA. THIS IS A VERY STRONG LOW AND BEARS WATCHING AS IT MAKES ITS CLOSEST APPROACH ON MON. THE NAM AND CMC IS IMPLYING A MORE WWD TRACK THAT WOULD HAVE AT LEAST SOME IMPACTS ON CSTL AREAS OF NJ. THE MORE WWD SOLN HAS SEEMINGLY WON OUT THIS SEASON, WITH THE JAN BLIZZARD AND EVEN THE SYS EARLIER THIS WEEK, SO THIS SOLN IS NOT TERRIBLY FAR FETCHED. HOWEVER, THE PREPONDERANCE OF THE MDL GUID CONTINUES TO BE AGAINST IT. IF IT WERE TO PRECIP MON AFTN, IT WOULD BE TOO WARM IN MANY AREAS FOR SNOW. THE NEXT SYS WILL THEN DEVELOP SOMEWHERE OFF THE MID-ATLC CST MON NIGHT. MDL GUID CONTINUES TO STRUGGLE TO RESOLVE THE DETAILS OF THIS SYS AND CONFIDENCE REMAINS MUCH BELOW AVERAGE. THIS LOW WILL MOVE NEWD THRU TUE. THE ECMWF MADE A PRONOUNCED EWD SHIFT THIS CYCLE AND IS MUCH DRIER AS A RESULT ON TUE. THE GFS SHIFTED SLIGHTLY FURTHER E, BUT REMAINS WETTER. THE CMC IS THE WETTEST SOLN OF ALL. ANOTHER FACTOR TO CONSIDER IS TEMPS. THE GFS HAS HAD A WARM BIAS WITH BOTH THE JANUARY BLIZZARD AND THE SYSTEM EARLIER THIS WEEK, BUT ITS TEMPS ARE FAIRLY CLOSE TO THE ECMWF. THAT WOULD SUGGEST FOR AREAS FROM THE I-95 CORRIDOR S AND EWD SFC TEMPS WOULD BE ABV FREEZING ON TUE. WHILE THERE COULD BE SOME DIABATIC COOLING, IF THINGS GET WARM ENOUGH THERE COULD BE MIXING OR EVEN A CHANGE OVER OR SNOW THAT FALLS AND DOESN`T ACCUMULATE, ESPECIALLY DUG THE DAYLIGHT HOURS. BASED ON ALL THIS UNCERTAINTY, ESPECIALLY THE EWD SHIFT OF THE ECMWF (DESPITE ITS LESS THAN STELLAR PERFORMANCE THIS WINTER), SEE NO REASON TO INCREASE SNOW AMTS AT THIS TIME AND WILL ONLY MAKE SOME MINOR TWEAKS. KEY TAKEAWAYS HERE, WHILE THERE IS STILL ALOT OF UNCERTAINTY WITH THIS STORM, JANUARY 23RD THIS IS NOT. A COUPLE OF INCHES IS PSBL. SOME PLACES CUD GET MORE, SOME LESS. AS THIS LOW PULLS AWAY, CANADIAN HIGH PRES WILL BUILD INTO THE MID-SECTION OF THE COUNTRY AND EVENTUALLY BUILD EWD. TEMPS WILL STRUGGLE TO CLIMB OUT OF THE 30S BY THE END OF THE WEEK.
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&& .AVIATION /21Z SATURDAY THROUGH THURSDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH ONLY CIRRUS CLOUDS EXPECTED THROUGH MOST OF SUNDAY. CLOUDS WILL BEGIN TO THICKEN AND LOWER DURING THE AFTERNOON FROM SOUTH TO NORTH AS A SYSTEM APPROACHES FROM THE SOUTH, BUT AGAIN REMAIN VFR THROUGH THE DAY. SOUTHWEST WINDS 5-10 KNOTS THIS AFTERNOON WILL BECOME LIGHT AND VARIABLE/CALM EVERYWHERE OVERNIGHT AS HIGH PRESSURE REMAINS ACROSS THE AREA. WINDS WILL PICK UP AGAIN OUT OF THE NORTH TO NORTHEAST DURING THE DAY SUNDAY. OUTLOOK... SUN NIGHT...VIRTUALLY ALL OF THE GUID CONTINUES TO KEEP THE STRONG STORM OFFSHORE. HOWEVER, ANY WESTWARD SHIFT IN THE TRACK MAY BRING A PERIOD OF LIGHT RAIN AND/OR SNOW TO EASTERN TERMINALS. OTHERWISE, VFR CONDS ARE EXPECTED. MDT CONFIDENCE. MON AND TUE...LOWER THAN AVERAGE CONFIDENCE THIS PD, AS A STORM SYS MAY DEVELOP NR THE MID-ATLC CST AND PRECIP MAY OVERSPREAD THE AREA MONDAY AFTERNOON AND EVENING. THERE ARE UNCERTAINTIES WRT THE TRACK OF THIS SYS AS WELL AS TEMPS ON TUE. PRECIP SHUD BEGIN AS RAIN LATER MON AND SHUD CHANGE OVER TO SNOW MON NIGHT. ON TUE, PRECIP COULD CHANGE BACK OVER TO RAIN ESPECIALLY FROM THE I-95 CORRIDOR SE, BUT HERE IS WHERE THE GREATEST UNCERTAINTY LIES. POTENTIAL FOR IFR RESTRICTIONS ESPECIALLY ONCE IT CHANGES OVER TO SNOW. HIGH UNCERTAINTY EXISTS ALSO FOR SNOW AMTS. WED...IMPROVING CONDITIONS. MAINLY VFR ALTHOUGH THERE IS A SMALL RISK FOR A BRIEF RESTRICTION WITH A PASSING SNOW SHOWER. MDT CONFIDENCE. THURSDAY...VFR. HIGH CONFIDENCE.
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&& .MARINE... SUB-ADVISORY CONDITIONS WILL PREVAIL ACROSS THE WATERS TONIGHT AS HIGH PRESSURE CONTINUES TO AFFECT THE AREA. WINDS WILL BEGIN TO INCREASE FROM THE SOUTH TO THE NORTH DURING THE AFTERNOON SUNDAY AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN AHEAD OF THE APPROACHING SYSTEM FROM THE SOUTH. A SMALL CRAFT ADVISORY IS NOW IN EFFECT STARTING AT 1 PM SUNDAY, THOUGH THE WINDS WILL LAG A COUPLE OF HOURS ACROSS THE FAR NORTHERN WATERS. OUTLOOK... SUN NIGHT AND MONDAY...THE GALE WATCH WILL REMAIN IN EFFECT. THERE IS A LOT OF UNCERTAINTY WITH RESPECT TO THE TRACK OF THE LOW AND, THEREFORE WE DID NOT OPT TO RAISE TO A GLW ATTM. IT WILL EITHER BE A VERY STRONG SCA OR MARGINAL GLW. MON NIGHT THROUGH THU...ANOTHER AREA OF LOW PRESSURE WILL DEVELOP OFF THE MID-ATLANTIC COAST. AN EXTENDED PERIOD OF SCA CONDITIONS LIKELY DURING THIS TIME. IT COULD POTENTIAL REACH GALE FORCE LATE WED INTO THU BUT UNCERTAINTY IS VERY HIGH REGARDING THE STRENGTH OF THE WINDS. && .TIDES/COASTAL FLOODING...
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WE ARE WATCHING TWO POTENTIAL COASTAL FLOOD EVENTS NEAR THE MONDAY MORNING HIGH TIDE AND TUESDAY MORNING HIGH TIDE.. THE FLOW WILL BECOME ONSHORE SUNDAY AFTERNOON AS HIGH PRESSURE ANCHORS OVER SOUTHEAST CANADA AND LOW PRESSURE DEVELOPS OFF THE CAROLINAS. THIS AREA OF LOW PRESSURE IS EXPECTED TO PASS WELL SOUTHEAST OF OUR REGION. WITH THE AFOREMENTIONED HIGH REMAINING TO OUR NORTH, ANOTHER AREA OF LOW PRESSURE WILL DEVELOP OFF THE OUTERBANKS OF NORTH CAROLINA MONDAY NIGHT AND PASS SOUTHEAST OF OUR REGION DURING THE DAY TUESDAY. THESE TWO SYSTEMS WILL MAINTAIN AN ONSHORE FLOW ALONG THE COAST TO VARYING DEGREES SUNDAY THRU TUESDAY. ASTRONOMICAL TIDES WILL BE HIGH TO BEGIN WITH, GIVEN THE NEW MOON ON MONDAY, REACHING THEIR PEAKS DURING THE MONDAY AND TUESDAY MORNING HIGH TIDES. FOR THE MONDAY MORNING HIGH TIDE, THE THREAT OF COASTAL FLOODING WILL BE HIGHEST ALONG THE NORTHERN NJ COAST, WHERE THE GREATEST COMPONENT OF ONSHORE FLOW WILL BE PRESENT. GIVEN THE SHORT DURATION OF STRONGER ONSHORE FLOW, THE WIND BACKING FROM THE NORTHEAST TO NORTH /MORE OFFSHORE/ AS WE APPROACH HIGH TIDE, AND CONTINUED UNCERTAINTY REGARDING THE STORM TRACK, CONFIDENCE REGARDING IMPACTS IS LOW. AT THIS TIME, THERE IS THE POTENTIAL FOR AT LEAST MINOR COASTAL FLOODING, PARTICULARLY THE NORTHERN NJ COAST. REGARDING THE TUESDAY MORNING HIGH TIDE, A MORE ROBUST AREA OF LOW PRESSURE IS EXPECTED TO TRACK CLOSER TO THE COAST, WITH A STRONGER ONSHORE FLOW. ASIDE FROM A BRIEF LULL IN THIS FLOW LATE MONDAY, WE`LL HAVE HAD NEARLY 48 HOURS DURATION OF ONSHORE FLOW, WHICH WILL MAKE FOR POSITIVE TIDAL DEPARTURES TO BEGIN WITH. IN ADDITION, A MORE EASTERLY WIND WILL MAKE FOR A LONGER FETCH IN TERMS OF BUILDING WAVE ACTION. BUT THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE EVOLUTION OF THIS LOW AND ASSOCIATED LOW-LEVEL JET, SO AGAIN OUR CONFIDENCE REGARDING IMPACTS IS LOW. AT THIS TIME, THERE IS THE POTENTIAL FOR MORE WIDESPREAD MINOR COASTAL FLOODING. PLEASE STAY TUNED TO LATER FORECASTS AND POSSIBLE HEADLINES.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WATCH FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR ANZ450>455. SMALL CRAFT ADVISORY FROM 1 PM TO 8 PM EST SUNDAY FOR ANZ450>455. SMALL CRAFT ADVISORY FROM 8 PM SUNDAY TO 6 AM EST MONDAY FOR ANZ430-431. && $$ SYNOPSIS...NIERENBERG NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...NIERENBERG AVIATION...NIERENBERG/ROBERTSON MARINE...NIERENBERG/ROBERTSON TIDES/COASTAL FLOODING...

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