Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 232327 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 727 PM EDT MON MAY 23 2016 .SYNOPSIS... The low offshore will begin to lift northeast away from our region tomorrow. In the wake of that low, a ridge will build over our region Wednesday and Thursday. The ridge will slowly shift east through the remainder of the week. A few small troughs around the edge of the high will keep unsettled summer like conditions for through the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
The early evening forecast was updated to account for the latest trends in radar, mesoanalysis and short-range forecasts from convection-allowing mesoscale models for tonight. The bulk of the convective activity this afternoon and currently as we approach sunset was confined along a corridor of relatively greater instability (owing to stronger heating in the afternoon and moisture pooling that developed) along and just west of the I-95 corridor. Convection as seen on radar has weakened over the past 1-2 hours and will continue to dissipate after sunset as the boundary layer stabilizes from the loss of solar heating. There will still be some showers focused along the I-95 corridor and Delmarva thru the remainder of the evening. The shower activity is expected to shift toward the coast overnight into early Tuesday morning as the coastal low and upper low both move northeastward. Previous Discussion... The surface is located to the southeast of the area and will make its way north and then east through tonight. The upper level low is located just off the Carolina coast and gradually pushing eastward. As the upper low pushes east, it will help to move the surface low away from our area. Scattered showers and thunderstorms have developed across the region this afternoon. As we head into this evening, these showers will weaken and dissipate from west to east. The cumulus will start to dissipate as we lose prime surface heating but cirrus will continue to push in from the east. While skies may start to clear, we anticipate that there will still be decent cloud cover overnight. In areas where we see rain this evening, we may start to see some fog development overnight as winds will go light and variable. If the clouds clear more than expected, fog may become more widespread across the region. Temperatures are expected to fall into the 50s across the region overnight.
-- End Changed Discussion --
&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... The upper low makes it way away from the eastern seaboard on Tuesday. The surface low will also make its final push off to the east of the area. Some energy rotating through the flow will help to spark some showers on Tuesday, possibly an isolated thunderstorms as well. We should start to dry out from southwest to northeast as we head through the afternoon and into the evening. Temperatures will be closer to normal with highs into the 70s through much of the region. Areas along the coast may remain closer to the upper 60s. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Wednesday and Thursday...Upper level ridge will shift east, with the ridge axis over our region by Thursday morning. If the departing upper level low is slower to lift away from the region than expected, the ridge may flatten a bit as the axis approaches our region. The few models that are depicting this pattern are showing showers across the Poconos and NW NJ late Wednesday as the ridge weakens. For now have kept Wednesday and Wednesday night dry as even if the ridge weakens slightly, there should be considerable synoptic scale subsidence over our region. Once the ridge axis shifts east of our region by late Thursday, we`ll be close enough to the periphery of the ridge that we could begin to see primarily diurnally driven showers and thunderstorms, initially confined to the NW portions of our region. Of more certainty is that the region will have a very noticeable warming trend, with 80s expected across much of the region both days. Friday through Monday...There continues to be poor model agreement and run to run consistency through this period, primarily as it relates to a backdoor cold front in the region Friday or Saturday. Most model solutions keep this front north of the region, but a few models and ensemble members bring it as far south as our region. If this scenario is correct, persistent onshore flow could result in temperatures well below normal especially Saturday and Sunday, and generally light and steady precip through much of the period. For now though, have not included this in the forecast, it seems an unlikely pattern for late May that a cold front would be able to push this far south under an upper level ridge. Even with models and ensemble members that show the ridge lingering over the region, should still see chances for showers and thunderstorms through the weekend as the region could be on the periphery of the ridge. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through tonight...Showers are popping up across the region this afternoon with some isolated thunderstorms affecting the terminals. As we head into tonight, the showers and thunderstorms are expected to dissipate from west to east. Winds will become light overnight and skies may even start to clear. Should clearing occur, some fog will be possible especially in areas where low level moisture has increased due to precipitation. We have included some 4-6sm fog in the taf during the overnight/early morning hours. Tuesday...mainly VFR conditions are expected across the region. Any fog should clear between 12-14z. Another round of scattered showers is possible and even a few thunderstorms may occur. All activity will decrease as we head towards the late afternoon/evening. Winds will turn to the west for Tuesday. Outlook... Wednesday...VFR conditions expected. Thursday through Saturday...Intermittent MVFR conditions with showers and thunderstorms possible each day. && .MARINE...
-- Changed Discussion --
The Small Craft Advisory was cancelled farther north for the Coastal Atlantic zones of southern NJ with seas subsiding to near 4 ft. The Small Craft Advisory was converted to a Small Craft Advisory for Hazardous Seas for the Coastal Atlantic zones south of Cape May with seas expected to remain near 5 ft thru midnight or shortly after in response to an offshore surface low. As the low moves north tonight and then pulls away to the east, seas will start to subside. Outlook... Wednesday through Saturday...winds and seas should stay below SCA criteria. RIP CURRENTS... There is a moderate risk of rip currents at the Delaware Beaches through this evening.
-- End Changed Discussion --
&& .PHI WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory for hazardous seas until 2 AM EDT Tuesday for ANZ454-455.
-- End Changed Discussion --
&& $$ Synopsis...Johnson Near Term...Klein/Meola Short Term...Meola Long Term...Johnson Aviation...Johnson/Meola Marine...Johnson/Klein/Meola

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.