937 FXUS61 KPHI 061413 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 913 AM EST Sun Nov 6 2022 .SYNOPSIS... High pressure will continue moving into the Atlantic today as a cold front approaches from the northwest. This front will pass through the region on Monday. High pressure will return to the region by the middle part of the week. A low approaching from the south will bring a chance of rain late next week. && .NEAR TERM /THROUGH MONDAY/... 910 AM...For the mid morning update, POPs were increased over eastern PA for this morning based on current radar and trends as an area of light rain affects this region. Otherwise, there were no changes made to the forecast and previous discussion follows below. For today, a weak embedded short wave trough in the mid and upper levels is bringing the first round of light showers this morning, mostly for areas north and west of the 95 corridor. The second round of rain will be possible later today and tonight. the mid and upper level flow becomes more zonal with the polar jet likely to be over the Great Lakes region. This will mean any synoptic scale lift should stay well north of our region. However, by late tonight into Monday morning, the cold front will be approaching. The modest isentropic lift along and just ahead of the front will be enough for some additional shower chances. With this round there remains a small chance for embedded thunderstorms, mostly for areas north and west of the 95 corridor. Though model soundings show very little in the way of instability, I have forecasted high temperatures above most guidance (as yesterday guidance had a cold bias, and we should have a relatively similar set up today). If the temperature trends hold, surface based instability will be a bit higher than what model soundings depict. That being said, the instability will still be weak, even with a warmer boundary layer, so still expecting precipitation to be mostly showers, with just a few thunderstorms. In general, models were a bit faster with the arrival and passage of the front on Monday; there is fairly good agreement that the front will be near or off shore by early Monday afternoon. Consequently, I trended the forecast for high temperatures down slightly, as cold air advection should be starting before the afternoon. This would mean the further west a climate site is (like MPO, RDG, and ABE), the less likely to see near record highs. Still some potential for record highs for GED, 55N, and ACY depending on how quickly the front moves through. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... Quiet weather will return for the short term as Canadian high pressure builds southeastward from southern Canada in the wake of Monday's cold front. Initially, with pressures rising and the gradient remaining elevated, the wind will keep temperatures from getting too cold Monday night, though cold advection will be underway, and it will be considerably cooler than the prior nights. Clear skies will prevail, with lows in the upper 30s to lower 40s. Cold advection will gradually end on Tuesday as the surface ridge axis pushes overhead, though the high center will remain to our northwest. The gradient will remain a bit elevated so a chilly breeze should prevail most of the day. Highs will struggle to reach 60, with most locations likely falling short despite plenty of sunshine. The low humidity and breeze may create a fire weather concern, which will continue to be monitored. Coldest night of the week likely occurs Tuesday night as the high passes by to the north and the gradient weakens. That said, not really expecting anything earth shattering or even a low point for the season, with temps in the cold spots reaching the 20s, but most locales getting no lower than the 30s. Thus, while frost headlines may be necessary, not really anticipating any further freeze warnings for those locations which have not had a freeze yet. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... High pressure will pass over New England Wednesday as it heads towards the North Atlantic. The gradient will remain light and the air mass cool, but warm advection will be about to start. This will get underway Wednesday night and Thursday for sure, as return flow on the backside of the high will bring milder air northward. Thus, while temps again struggle (and likely mostly fail) to reach 60 on Wednesday, Thursday should see most areas well into the 60s. By this point, our attention turns to the potential tropical/extratropical interaction which may affect our region towards the end of the week into the start of the weekend. A potent upper trough and surface low will be making its way eastward across the central US later this week. Guidance is also gradually coming into agreement regarding a system with at least some tropical aspects affecting the southeast later in the week. These two systems look likely to interact as the upper trough pulls the southern system northward up the coast Friday and Saturday. A lot of questions remain regarding exact timing and track, but there is definite potential for at least some heavy tropically-enhanced rain, if not any other hazards from this interaction. We will be watching this potential very closely over the coming days. The one bit of good news for many is that this northward moving system will provide relatively mild temperatures as we reach the end of the week. However, the mild weather won't last, and much colder weather returns behind the cold front for the latter portion of the weekend. There may even be a few flurries in the higher terrain at some point. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...Scattered showers possible, generally north and west of the I- 95 corridor. KRDG and KABE are the most likely to see any impacts. In general, expecting prevailing VFR, though brief periods of MVFR (primarily for ceilings) will be possible. Can't rule out some isolated thunderstorms, primarily in the afternoon and evening, but the potential is too low to include in the TAFs at this time. Southerly winds around 10 gust 20 kt. Moderate confidence on the overall pattern, but low confidence on SHRA or TSRA impacting any one TAF site. Tonight...Similar to today, mostly VFR with isolated showers. The chance for SHRA should progress east through the night, but impacts, if there are any, should be brief with transient MVFR ceilings. Southerly winds 5 to 15 kt. Moderate confidence on the overall pattern, but low confidence on the timing or potential of MVFR ceilings. Outlook... Monday...VFR conditions expected. Winds will abruptly shift from southerly to northwesterly with a cold front as early as mid to late morning for KRDG and KABE, to as late as late afternoon for KACY. Wind speeds behind the cold front of around 10 gust 20 kt. Moderate confidence. Tuesday...VFR. Northerly winds around 10 kts with gusts up to 20 kts during the day. High confidence. Wednesday...VFR. Northeasterly winds 5 to 10 kts become less than 5 knots overnight. High confidence. Thursday...VFR. Southeasterly winds 5 to 10 kts. Moderate confidence. && .MARINE... Although seas are elevated early this morning, they are staying just below 5 ft, and wave heights are expected to stay steady or decrease slightly through the day. Thus winds and seas should stay below SCA criteria through Monday. On Monday however, expect an abrupt wind shift from southerly to northwesterly. The timing of this wind shift could be as early as mid day for portions of the Delaware Bay to as late as early evening for the Atlantic coastal waters. Outlook... Monday night through Wednesday...SCA conditions likely. Winds and waves increase late Monday night into Tuesday and continue at least partly into Wednesday. Gusts 25 to 30 kts with northwesterly to northeasterly prevailing winds. Seas 5 to 7 feet. Wednesday night through Thursday...SCA conditions possible. Winds decrease to below SCA conditions beginning Wednesday night with northeasterly winds around 10 to 15 kts. SCA wave conditions may persist through Thursday with 3 to 5 feet seas expected. Thursday night through Friday night...SCA conditions possible. Winds becoming easterly to southeast and possibly increasing 15-20 kts with gusts possibly up to 30 kts by Friday night. Waves initially 2-4 feet may return to 3-6 feet by Friday night. && .CLIMATE... Record highs Saturday were tied at Atlantic City ACY, and Allentown ABE. A record high was set Saturday at Reading RDG. Record warm lows were also set or tied at ACY, 55N and MPO. Record highs are possible for both maximum and minimum temperatures today and Monday,though record warm lows Monday likely fall short given midnight temperatures are expected to be significantly lower. Here are the records which may be reached: Maximum: SITE: Sun 11/6 Mon 11/7 PHL 79/1948 76/1938 ILG 79/1948 75/2020 ABE 78/1948 74/1938 ACY 77/1961 77/2020 TTN 77/1948 76/1975 RDG 79/1975 74/2020 GED 82/1948 77/2004 MPO 69/1978 71/2020 55N 72/1999 70/2020 Minimum: SITE Sun 11/6 Mon 11/7 PHL 66/2015 61/1938 ILG 64/2015 59/1938 ABE 64/1938 64/1938 ACY 64/2015 59/1977 TTN 65/2015 59/1938 RDG 64/1938 63/1938 GED 65/1959 60/1977 MPO 59/2015 55/1938 55N 64/2015 61/1938 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...RCM NEAR TERM...Fitzsimmons/Johnson SHORT TERM...RCM LONG TERM...RCM AVIATION...Fitzsimmons/Johnson/RCM MARINE...Johnson/RCM CLIMATE...