896 FXUS61 KPHI 301757 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1257 PM EST Tue Nov 30 2021 .SYNOPSIS... A weak trough passes through the region today, and then weak high pressure passes through the region on Wednesday. A warm front lifts north Wednesday night, followed by a cold front on Friday. Weak low pressure may affect the area over the weekend, followed by a potentially stronger system on Monday. && .NEAR TERM /THROUGH TONIGHT/... Light snow continues to work across the northwestern half of the CWA this afternoon, mostly north and west of I-95 with a few sprinkles or drizzle drops along I-95 as dry air wins the battle against our snow fiend. Light snow has been persistent across the Lehigh Valley all morning, but is quickly winding down as the jet max moves off the the north and east, taking the weak area of ascent with it. Mostly cloudy skies will continue through the remainder of the afternoon, however. Highs will range from the 30s over the southern Poconos and NW NJ to the low to mid 40s near the I-95 corridor where despite little if any precip, it should be a mostly cloudy day. Our southern Delmarva zones and far southern NJ will see highs in the upper 40s to around 50. The weak system continues to zip off to the east tonight with high pressure building back in over the east coast resulting in at least some partial clearing. Lows by Wednesday morning will be mostly in the 20s to low 30s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... Weak high pressure passes through the region on Wednesday. Temperatures rebound back a bit closer to normal levels, with highs in the 30s to the north and otherwise in the 40s to low 50s in southern Delmarva. A fairly interesting set up then on tap for Wednesday night through Thursday morning. Low pressure tracking across southern Canada will drag a warm front north through the region Wednesday night. This warm front will be associated with some strong shortwave energy and a mid-level trough. Conditions will be fairly dry out ahead of this system with surface dew points in the 20s to low 30s throughout the day. A light southerly flow develops at night, but no not think the flow will be strong enough to usher strong enough moisture advection until late at night and more in the pre-dawn hours of Thursday morning. As a result, there is the potential for wet-bulbing for the start of the night through midnight or so that could yield more in the way of wintry precip. Another concern is that there is little consistency among the models in terms of QPF amounts. Regardless, QPF amounts will be light, but the 00Z/30 NAM is almost dry, whereas the 00Z/30 operational GFS has almost 2/10 inch QPF, and the 00Z/30 ECMWF has less than 1/10 inch QPF. Given that this system looks weak overall, trended with WPC QPF and keep QPF at less than 1/10 inch throughout from Wednesday night through Thursday morning. In terms of p-type, based on surface temps, will keep precip plain rain south of the Fall Line, but PoPs will generally range from low chance to slight chance. Again, not expecting much in the way of QPF during the overnight/early morning hours. The concern comes north and west of the Fall Line. Temps start out cold enough for all snow in the southern Poconos. However, BUFKIT soundings indicate mid-level drying and WAA tat would result in a change from snow to a mix to a period of freezing rain across the Lehigh Valley, southern Poconos, and northern New Jersey. Again, QPF will be light, so not expecting much more than a glaze or so of ice, although a hundredth of an inch or so is possible. Before the changeover, less than an inch of snow is possible in portions of Carbon and Monroe counties. Warm front lifts north and departs Thursday morning. Precip tapers off as all rain, then conditions will be dry in the afternoon. With WAA underway, temps warm up to above normal levels on Thursday with highs in the 50s throughout, and around 60 in southern Delmarva. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A cold front crosses the region Thursday night through Friday morning with no precip. It is possible some lake effect streamers could spread down towards far northwest New Jersey and portions of the southern Poconos, but for now, will keep it dry with no PoPs. Temps cool off for Friday. Weak high pressure then passes through the region Friday through Saturday, followed by another cold front on Sunday. Models not indicating much, if any, precip. PoPs will be capped at slight chance/low chance Friday night/Saturday morning, and then conditions look dry on Saturday and Sunday. A stronger storm looks to develop and impact the region Sunday night and Monday. There are inconsistencies in terms of timing and placement of this storm between the GFS and the ECMWF. The GFS has the storm developing over the Midwest, and it tracks to the northeast through the Ohio Valley, western New York, and into eastern Canada. The ECMWF has the low tracking from east to west from the Midwest through the Great Lakes and Ohio Valley, across Pennsylvania and through northern New Jersey. ECMWF has more precip over the local area. Given these inconsistencies, will therefore stick with NBM PoPs, which for now, are low-end chance. Overall, precip may start out as rain in the southern half of the forecast area and snow in the northern half of the forecast area, changing to rain on Monday. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...For MIV/ACY, VFR with southwest winds around 10 kt. CIGs may approach MVFR thresholds for a time through 21z. Cannot rule out a few flurries, but no impacts are expected at the terminals. Winds becoming southwest 5 to 10 kt by afternoon. For RDG/ABE, light snow will continue through 20, with MVFR/IFR conditions possible at times. Light southwest winds. Conditions should improve after 20z. Confidence for today...High at MIV/ACY; moderate at the Philly terminals; low at RDG/ABE. Tonight...Mainly VFR with light southwest winds. Moderate confidence. Outlook... Wednesday...VFR. SW winds 5-10 kt. High confidence. Wednesday night...A period of MVFR or possibly IFR CIGs/VSBYs possible. A wintry mix possible at KRDG/KABE and plain rain elsewhere. S winds 5-10 kt. Moderate confidence. Thursday...Lingering rain in the morning, otherwise, VFR. SW winds 5-10 kt. Moderate confidence. Friday...Primarily VFR. W winds 10-15 kt. Moderate confidence. Saturday...A brief period of sub-VFR possible in the morning, otherwise VFR. W-W winds 5-10 kt. Moderate confidence. && .MARINE... A Small Craft Advisory for our coastal waters off southern New Jersey and Delaware running until 7 PM as gusts to 25 knots are expected through the afternoon here before diminishing in the early evening. Over the remaining coastal waters and the Delaware Bay gusts should be closer to 20 knots. Expect seas to generally remain around 3 to 4 feet through tonight. Outlook... Wednesday through Wednesday night...Sub-SCA conditions. Thursday through Thursday night...SCA conditions likely for both winds and seas. Friday through Saturday...SCA conditions Friday, gradually subsiding to sub-SCA conditions on Saturday. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ453>455. && $$ Synopsis...MPS Near Term...Davis/Fitzsimmons Short Term...MPS Long Term...MPS Aviation...Fitzsimmons/MPS Marine...Fitzsimmons/MPS