Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 241922 CCA AFDPHI Area Forecast Discussion...CORRECTED National Weather Service Mount Holly NJ 322 PM EDT Mon Oct 24 2016 .SYNOPSIS... High pressure near Hudson Bay Canada will build closer to our region through mid week. A warm front on Thursday will be followed by a cold front Thursday night as low pressure redevelops from near Lake Erie Thursday to Long Island Friday morning. Weak high pressure quickly follows Friday night before low pressure and its associated frontal systems cross the mid Atlantic states Saturday. High pressure will become dominant over our area by next Monday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... A relatively quiet night expected tonight across the area. Partly to mostly cloudy skies late this afternoon and early evening will become mostly clear later this evening overnight. Clouds may begin increasing across the northern areas as we approach daybreak Tuesday. Also, with these advancing clouds, it is possible for some sprinkles or flurries to occur across our far northern areas as some enhanced moisture/lift moves into the area within the northwest flow. Any precipitation amounts are expected to be light. Winds will remain gusty for the late afternoon hours, diminishing some around sunset and through the evening. With an area of low pressure well to our north and high pressure well to our northwest, we continue to keep a tight pressure gradient across the area. This will keep a steady flow across the area through tonight with winds generally 5-10 mph overnight, even once the gusts drop off. Temperatures will cool significantly tonight compared to last night with widespread 30s, and some 40s. However, with the expected wind and possible increase in clouds late, we do are not expecting widespread frost, so we do not anticipate a frost advisory for tonight/Tuesday morning at this time. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... There could continue to be some sprinkles/flurries at the start of the day Tuesday due to the enhanced moisture/lift across the area within the northwest flow. Any precipitation should dissipate through the morning, however, clouds cover should expand and increase in coverage across the area during the day. Winds will again become gusty through the day with gusts reaching 25- 30 mph at times across the area. With the winds, it will feel much cooler than the actual air temperature with is expected to be mostly in the 50s, with 40s across the far northern areas. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... *Long Term will be updated by 4 pm.* Tuesday...Cold air advection pattern continues with Tuesday night likely being the coldest night of the season so far for many locations. Highs on Tuesday are expected to be 5 to 15 degrees below normal. For Tuesday night, current forecast lows in the Lehigh Valley, Pine Barrens and the remainder NW NJ (areas that have not yet had a freeze) are right around freezing (31 to 33). At the very least, it looks likely that these areas will see frost and could see a freeze. The Philly metro and Delmarva should be a bit warmer, but could also see patchy frost. Wedensday...Cold air advection continues for one more day, so expect highs on Wednesday to be a few degrees lower than Tuesday. Wednesday night through Thursday night...Most of the other deterministic models have come into closer agreement with the more progressive timing of the GFS. The good news with this solution is that cloud cover should increase rather early on Wednesday night, limiting radiational cooling (and also consequently making frost unlikely). The bad news is that even so, precip arriving ahead of the surface warm front due to warm air advection aloft and a mid level short wave trough, could be a wintry mix across the southern Poconos and NW NJ. Current model soundings of the GFS indicate a warm layer from just above the surface through 7000 or 8000 ft AGL. This would suggest more of a rain or freezing rain situation. However, previous model runs depicted more of a rain/snow mix, so for now will continue with that in the forecast, and continue to mention potential for icy spots in these areas on Thursday morning. In addition to the earlier arrival of the precip, the dry slot and surface cold front is also now expected to arrive earlier in our region, leading to precip ending quickly on Thursday night if this timing holds true. Friday...a short wave ridge slides over the region through the day, leading to quickly clearing skies and limiting the period of cold air advection. Saturday and Sunday...models are depicting another low pressure system sliding over or just north of the region. As such, chances for precip through this time period have increased from previous forecasts. For now have stayed close to a blend of model guidance until there is better run to run consistency. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. VFR conditions will continue through the TAF period. The scattered to broken stratocumulus clouds around 4,000-6,000 feet this afternoon will dissipate this evening and overnight with the loss of daytime heating; although there could still a few lingering clouds around overnight. The main concern is the gusty winds today and again Tuesday. Northwest Winds will continue to gust around 25-30 knots this afternoon. The gusts will diminish some around sunset to around 15- 20 knots, with the gusts expected to drop off overnight. The gusts will return Tuesday with gusts 20-25 knots again, with some locally higher gusts 25-30 knots possible. Outlook... *Outlook will be updated by 4 pm.* Tuesday and Wednesday...Mostly VFR conditions expected. Wednesday night and Thursday...ceilings will lower to MVFR (with localized IFR) by day break Thursday. Visibility restrictions possible with rain showers Thursday into Thursday evening. Friday...Ceilings should return to VFR early in the day. && .MARINE... Small craft advisory remains in place for tonight and has been extended into Tuesday as winds are expected to continue to gust 25- 30 knots across the waters tonight into Tuesday. Wind gusts on the Delaware Bay may drop below 25 knots overnight, but are expected on increase again on Tuesday. Outlook... *Outlook will be updated by 4 pm.* Tuesday...On the coastal waters could have gusts right around 25 kt, but confidence is low at this time. Wednesday...winds and seas should stay below SCA criteria through the day time hours. Thursday and Friday...winds are expected to build through the day on Thursday and could be near SCA criteria on the coastal waters. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Freeze Watch from late Tuesday night through Wednesday morning for PAZ060>062-101>103-105. NJ...Freeze Watch from late Tuesday night through Wednesday morning for NJZ008>010-012-013-019>022-027. DE...Freeze Watch from late Tuesday night through Wednesday morning for DEZ001. MD...Freeze Watch from late Tuesday night through Wednesday morning for MDZ008. MARINE...Small Craft Advisory until 11 PM EDT Tuesday for ANZ450>455. Small Craft Advisory until 6 PM EDT Tuesday for ANZ430-431. && $$ Synopsis...Drag Near Term...Robertson Short Term...Robertson Long Term...Johnson Aviation...Franck/Johnson/Robertson Marine...Franck/Johnson/Robertson is the U.S. government's official web portal to all federal, state and local government web resources and services.