Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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330 FXUS61 KPHI 181233 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 733 AM EST Sat Feb 18 2017 .SYNOPSIS... A warm front will lift north of the area today. A cold front is expected late tonight into early Sunday as an area of low pressure passes well to our north. Another cold front is forecast to push through the area early Monday, then high pressure moves into the area later Monday into Tuesday, before moving offshore Tuesday night. A weakening frontal is expected to move across the area early Wednesday. Another frontal boundary is forecast to approach the area Thursday and stall near the area through Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... It won`t feel much like a February day today! Warm front should lift from southwest to northeast through the first half of the day. I favored the warmer NAM MOS guidance for highs today as guidance has underestimated warm air advection with two recent events. The one exception to this is across the southern Poconos and far NW NJ where a snow pack remains (at least for now). Forecast max temperatures range from the upper 40s across the southern Poconos to upper 60s in southern Delaware. This is 10 to 20 degrees above normal, but still quite a ways off from daily record highs. Forecast highs are still 8 to 15 degrees below the record highs. Behind the warm front, expect southwesterly winds to pick up slightly, to around 10 KT, and continue through the day time hours. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... Winds should shift from southwesterly to westerly overnight, resulting in weak downslope low level flow. That, combined with the moisture advection, will limit radiational cooling. Lows are forecast to be 15 to 25 degrees above normal, ranging from the mid 30s to upper 40s. A closed mid level low, currently over OK and AR is expected to cross VA and Delmarva late tonight. However, it is expected to fill and weaken today and tonight as it does so. Thus, we are not expecting the same widespread convection currently on the front side of this low. However, isolated rain showers will be possible generally south of Philly as the low crosses Delmarva late tonight. && .LONG TERM /SUNDAY THROUGH FRIDAY/... On Sunday, the cold front that affects the area overnight Saturday will push through the area. Any precipitation associated with this boundary will end before daybreak, and a dry forecast is expected Sunday through Sunday night. Sunday is forecast to be a warm day, and several places could get within a few degrees of record. However, no one is expected to break any records at this time. A back door front is forecast to push southward through the area early on Monday before high pressure builds across the area later Monday into Tuesday. Cooler conditions are expected Monday and Tuesday as compared to Sunday, but will remain above normal. A warm front may pass across the area Tuesday into Tuesday night as high pressure shifts offshore. Dry weather should continue on into Tuesday. A cold front is then expected to approach the area Tuesday night and pass through during the day Wednesday. Precipitation may start overnight Tuesday as a short wave/vorticity impulse slides across the area. If preciptaiton starts early enough, there could be a wintry mix across the far northern areas, mainly along and north of I-80 corridor. Guidance indicates the precipitation beginning to dissipate as it approaches the east coast as the front moves through the area. So we`ll keep a chance/slight chance for isolated showers across the area Tuesday night into Wednesday. Another front is forecast to approach the area Thursday, then stall near the area through Friday. There is a chance that some scattered showers could develop overnight Thursday into Friday as a couple of short wave/vorticity impulses move across the area. However, the best chance for precipitation looks like Saturday as a stronger frontal boundary moves into the area. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. VFR conditions expected. Only high cirrus clouds are expected through most of the TAF period. Clouds may thicken and lower to around 10000 ft AGL near 06Z. Southwesterly winds will increase to around 10KT through the day time hours, before dropping off again after 00Z. OUTLOOK... Sunday-Tuesday...Generally VFR expected. CIGS may approach MVFR at times Sunday night into Monday morning. Gusty winds 15-20 knots during the day. Tuesday night-Wednesday...Conditions lowering to MVFR or IFR overnight into Wednesday morning with a chance of showers. && .MARINE... Winds and seas should stay below SCA criteria. Gusts above 20kt are possible late this afternoon and this evening, but winds are expected to remain below 25kt. OUTLOOK... Sunday-Monday...Generally sub Small Craft Advisory conditions expected, although winds may approach advisory levels across the northern New Jersey coastal waters overnight Sunday into Monday morning. Monday night-Wednesday...Sub Small Craft Advisory conditions expected although winds may gust up to 20 knots at times. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Robertson Near Term...Johnson Short Term...Johnson Long Term...Robertson Aviation...Johnson/Robertson Marine...Johnson/Robertson

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