Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
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. --
628 FXUS61 KPHI 241439 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1039 AM EDT Tue Sep 24 2024 .SYNOPSIS...
-- Changed Discussion --
High pressure over Atlantic Canada will gradually retreat eastward through Wednesday as a warm front starts to approach. Low pressure associated with this warm front will move eastward Wednesday and Thursday as it passes by to our north moving from Ontario and Quebec into New England. By the weekend, the area will be situated between high pressure to the north while low pressure will be to our south.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Few changes were needed during the late morning. A couple changes to sky cover grids with some limited sunshine appearing across NJ. A few tweaks to temperatures and winds too. High pressure continues to nudge from the northeast. This will result in a dry day overall, though with continuing onshore flow, a mostly cloudy to overcast day is expected. With a cool and moist maritime airmass remaining in place, temperatures will only get into the upper 60s/low 70s with low 60s in the Poconos. A digging trough moving through the central US will eventually cutoff near the Mississippi River with a split flow pattern developing. The result will be southwesterly flow aloft with weak positive vorticity advection beginning tonight. Additionally, weak warm air advection will set up tonight as a warm front approaches, and with a moist airmass already in place, some showers will begin to move in. However, the bulk of the rain should come in during the day on Wednesday (more on that below). Overnight lows will be in the upper 50s/low 60s.
-- End Changed Discussion --
&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... It will be a bit unsettled for parts of the short term period as a system brings parts of the area some much needed rainfall. For Wednesday, an upper level trough will be digging southward into the Great Lakes along with an associated trough at the surface. This will help push a warm front towards the area keeping skies mostly cloudy with some showers around. Expect that these showers will be heaviest and most persistent N/W of the urban corridor and more scattered to isolated farther south/east. In fact the coast may not see anything. Highs will range mostly from the upper 60s to mid 70s except a bit cooler over the Pocono Plateau. The trend will be for showers to generally diminish with time throughout the course of Wednesday night and Thursday with any lingering showers by Thursday being confined mainly to areas near and especially north of the urban corridor. This will occur as low pressure moves eastward from Quebec into eastern New England while high pressure starts to build back in over Central into western PA. Total rain amounts will be very minimal near the coast with a tenth to a quarter inch possible near the urban corridor and a half to three quarters inches possible over parts of NE PA into NW NJ. Expect skies to overall be partly to mostly cloudy Thursday with it being warmer and more humid compared to Wednesday as we will be in the warm sector. Highs will be mainly in the upper 70s to low 80s with dew points mainly in the mid to upper 60s. Weak surface ridging should try to build east into the area Thursday night keeping it mainly dry but with lingering cloud cover. Lows are expected to range from the mid 50s north to the mid 60s south. && .LONG TERM /FRIDAY THROUGH MONDAY/... There is more uncertainty than normal for the long range period as the pattern will be quite complex over eastern North America. To start the period early Friday, there will be an upper level low over the Canadian Maritimes with another upper low near the Gulf coast. Meanwhile upper level ridging will be over the Great Lakes with a surface high over PA. Finally, by this time the upper low near the Gulf coast will have likely pulled in the tropical cyclone which should be situated by this time somewhere over the SE CONUS. The main uncertainty hinges around whether some of the moisture to our south will be able to move northward bringing the area some rain this weekend or whether the ridging to our north will suppress it south. The latest guidance has generally trended toward bringing some decaying remnants of the system to our south a bit farther north suggesting an increased chance for rain this weekend along with more in the way of cloud cover. Given the continuing uncertainty in the forecast, we stayed close to the NBM which generally brings the area POPs of around 20 to 30 percent by late Friday and again for the day Saturday and Sunday. If the upper level low to our south is able to move far enough north to bring us rain for this weekend, this unsettled weather could linger into early next week as the upper level pattern will be quite blocky. As far as temperatures, they should be close to seasonal for the long range period with highs mostly in the 70s. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... This afternoon...Ceilings have lifted and scattered out across NJ and other areas will have limited improvements into the afternoon. Winds out of the east around 10 kt. Medium confid overall. Tonight...Scattered showers move in with ceilings coming down gradually, first to MVFR by the late evening, potentially down to IFR early on Wednesday morning. Winds out of the east around 5-10 kt. Low confidence. Outlook... Wed thru Wed night...Some showers along with low stratus could bring sub VFR conditions at times, especially for RDG and ABE. Thu thru Sat... Mostly VFR.
-- End Changed Discussion --
&& .MARINE... A Small Craft Advisory is in effect for all ocean zones as seas will be around 3 to 6 feet through Wednesday. On Delaware Bay, no marine headlines are expected as winds will be out of the east around 10-15 kt. Outlook... Small Craft Advisory level conditions are expected to continue through Wednesday...mainly due to seas 4 to 6 feet. Conditions should finally diminish below Small Craft Advisory conditions through Wednesday night. The sub-SCA may last thru Fri night with a possibility of another SCA Sat or Sunday. Scattered showers Tue night thru Wed night. Rip currents... There is a HIGH risk for the development of dangerous and life threatening rip currents at the Jersey Shore and at Delaware Beaches through Wednesday. The persistent onshore flow continues with easterly winds of 10 to 20 mph along with 3 to 5 ft breaking waves. Rip currents occur often in the vicinities of jetties and piers and the speed of the currents are generally maximized at low tides. For specific beach forecasts, visit weather.gov/beach/phi && .TIDES/COASTAL FLOODING... A prolonged period of onshore flow has resulted in a piling up of water along the coasts with this water unable to drain within tidal waterways. Coastal Flood Advisories are in effect today for Ocean County, NJ and Sussex County, DE mainly for minor and spotty moderate flooding in the back bays-Barnegat Bay in NJ, and Little Assawoman Bay and the Indian River Inlet in Delaware. Thought about extending the Advisory as some of the back bay tidal guidance keeps minor flooding through Wednesday, but will wait to see how today`s high tide cycle goes. For Delaware Bay, a Coastal Flood Advisory is in effect for Kent County, DE and Cumberland County, NJ for minor tidal flooding with this afternoon`s high tide. Following this afternoon`s high tide, no further advisories are anticipated. For the Eastern Shore of Maryland, a Coastal Flood Advisory remains in effect through tonight for minor tidal flooding around tonight`s high tide. May need to extend for one more high tide following tonight but will wait for more guidance to come in and see how high the evening high tide gets. Some spotty minor flooding remains possible along the southern New Jersey coast, with no tidal issues expected along the northern New Jersey coast (Monmouth and Middlesex County) and along the tidal Delaware River. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...Coastal Flood Advisory until 6 PM EDT this evening for NJZ020- 021-026. High Risk for Rip Currents through Wednesday evening for NJZ014- 024>026. DE...Coastal Flood Advisory until 6 PM EDT this evening for DEZ002>004. High Risk for Rip Currents through Wednesday evening for DEZ004. MD...Coastal Flood Advisory until 5 AM EDT Wednesday for MDZ012. Coastal Flood Advisory until 2 AM EDT Wednesday for MDZ015-019- 020. MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ450>455. && $$ SYNOPSIS...Fitzsimmons NEAR TERM...Hoeflich/po SHORT TERM...Fitzsimmons LONG TERM...Fitzsimmons AVIATION...Fitzsimmons/Hoeflich/po MARINE...Fitzsimmons/Hoeflich TIDES/COASTAL FLOODING...