Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 251028 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 628 AM EDT Mon Mar 25 2024 .SYNOPSIS... High pressure over southeast Canada will extend into the Mid- Atlantic region through Tuesday. An area of low pressure will track northwest of the area on Wednesday with a trailing cold front that will approach from the Midwest on Thursday. A coastal low may potentially develop along this front and track northward into the Canadian Provinces by Friday. High pressure returns late Friday ahead of a weak disturbance arriving later next weekend. && .NEAR TERM /THROUGH TONIGHT/...
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The weather remains quiet early this morning under a mainly clear sky with light winds. An area of high pressure remains centered to our north over Quebec while an ocean storm continues to sit and spin to our east several hundred miles out into the Atlantic. This low will meander around out there through the day today. As this occurs, the pressure gradient should tighten up some to its northwest into our area as we head through the morning. This combined with the strong high pressure to our north will result in dry and cool weather, however there will be an uptick in the winds today especially closer to the coast. Otherwise, a mostly clear sky is expected for today with highs climbing into the upper 40s/low 50s for most areas. The increasing northeast wind however will also become gusty at times especially closer to the coast. Wind gusts along the coast look to be about 30-35 mph. By tonight, the continuing northeast winds look to moisten the lower levels with forecast models still indicating a low stratus deck to form near the coast and advect inland bringing the area mostly cloudy skies by Tuesday morning. This will also result in it being a milder night with lows mostly in the low to mid 30s, except near 40 along the coast and over southern Delaware and in the upper 20s over the southern Poconos.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY/... The marine stratus deck looks to persist over the area much of Tuesday making for a mostly cloudy day. We also can`t rule out some drizzle near coastal areas due to the combination of northeast winds and moisture trapped underneath the surface inversion. Elsewhere, expect dry conditions under the mostly cloudy skies. High temperatures looks to be similar to Monday, generally in the upper 40s to low 50s. Moving into Tuesday night, the cold front associated with low pressure tracking north of the Great Lakes will begin to approach. With better forcing over our northern and western areas, some rain showers are possible. Overall, should remain pretty light in nature as frontal boundary will be weakening as it approaches. The cold front to the west will slow down in forward motion and continue to weaken as it approaches; coming to a crawl near our region on Wednesday. As the front potentially stalls, the majority of deterministic and ensemble long range guidance depicts a coastal trough and an eventual coastal low forming along the boundary on Thursday. This will bring another round of rain to the region, with PoPs holding steady mostly in the 60-80% range Wednesday night through Thursday (highest near the coast and lowest over N/W area of the County Warning Area). We will have to closely watch this system closely as it could once again bring some heavy rainfall to the area. Currently the majority of the deterministic model guidance has the heaviest rain falling near or off the coast but if this shifts N/W as some of the GEFS ensemble members suggest, it could once again bring significant rainfall towards or into the I-95 corridor. Confidence on these details though is low at this time. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... The coastal low described in the short term section could linger Thursday night perhaps even into early Friday depending on its strength, track, and speed. Also worth noting, a change to some wintry precipitation will be possible across the southern Poconos on the backside of the system before it departs. Thereafter, high pressure should eventually build back into the area by late Friday with seasonable temperatures. This high doesn`t look to be particularly strong over the area and by next weekend an east/west oriented frontal boundary looks to set up near the mid Atlantic. While the weekend doesn`t look to be a washout at this time some disturbances moving along this boundary could bring some showers from time to time. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... Through today...VFR. Northeasterly winds increasing through this morning to 8-15 knots with gusts 20-25 knots, strongest winds at KMIV and KACY. High confidence. Tonight...VFR early, becoming sub-VFR overnight with marine stratus developing and advecting inland...possibly not reaching RDG and ABE until around 10-12z Tuesday. NE winds 7-12 kt. Higher gusts up to 20 kt possible at KACY. Moderate confidence. Outlook... Tuesday through Tuesday night...Mainly sub-VFR. Drizzle possible near KACY during the day, with some showers developing at night. NE-E winds around 10 kt during the day, becoming 5 kt or less at night. Moderate confidence. Wednesday through Wednesday night...Sub-VFR with periods of rain. SE-S winds around 5-10 kt during the day, becoming NW-N winds around 5 kt late at night. Low confidence. Thursday through Thursday night...Sub-VFR with periods of rain. NW-N winds around 10-15 kt with gusts up to 20 kt. Low confidence. Friday...VFR or becoming VFR with clearing skies. NW winds around 15-20 kt with gusts up to 30 kt. Moderate confidence.
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&& .MARINE...
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Low pressure well offshore will meander out there through today. It`s close enough to keep winds up, however they should remain below Gale-force. Enhanced seas will continue. It appears the winds for the upper Delaware Bay will remain below Small Craft Advisory criteria while lower Delaware Bay will continue with advisory level gusts and seas (near the mouth) at least through the day today. For the tonight through Tuesday period, the winds will gradually subside however the seas will remain elevated so we`ve extended the Small Craft Advisory through the day Tuesday. Outlook... Tuesday night through Wednesday...SCA conditions likely to continue due to elevated seas generally 5 to 8 feet. Thursday...Marginal SCA conditions. NW-N winds around 10-20 kt. Seas of 4-5 feet. Thursday night through Friday...SCA conditions likely to return with even the potential for Gale force winds. NW winds around 15-25 kt with gusts 30 to 35 kt. Seas of 4-6 feet.
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&& .TIDES/COASTAL FLOODING... A low pressure system lingering well off the coast will result in an extended duration of long period swells and rough surf impacting the Atlantic coast. Surge values of 2-3 feet are currently forecast by today. This will result in widespread MODERATE flooding along the oceanfront and Delaware side of the Delaware Bay. Thus, we have issued Coastal Flood Warnings starting early this morning, when widespread MINOR flooding begins, but right now the highest tide appears to be this evening`s. Some guidance has MODERATE flooding lingering several cycles, but for now have cut off the warning at 2 PM Tuesday. Widespread MINOR flooding looks likely across the Cumberland County, NJ side of the Delaware Bay with this morning`s high tide and the Salem County, NJ and New Castle County, DE shores of the upper bay by this evening`s. Therefore, Coastal Flood Advisories were issued beginning early this morning and later this evening, respectively and both continue through mid- afternoon Tuesday as well with widespread MINOR flooding expected with each successive cycle. Spotty MODERATE flooding is also possible in these areas with the highest high tides this evening and Tuesday morning. Coastal flooding is not anticipated along the tidal Delaware River or the eastern shore of Maryland through the daytime high tides Tuesday. Spotty MINOR tidal flooding may be possible beyond this time but confidence remains low overall. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...Coastal Flood Advisory from 11 PM this evening to 3 PM EDT Tuesday for NJZ016. Coastal Flood Warning until 2 PM EDT Tuesday for NJZ020- 022>027. Coastal Flood Warning from 6 PM this evening to 2 PM EDT Tuesday for NJZ012>014. Coastal Flood Advisory until 2 PM EDT Tuesday for NJZ021. DE...Coastal Flood Advisory from 11 PM this evening to 3 PM EDT Tuesday for DEZ001. Coastal Flood Warning until 2 PM EDT Tuesday for DEZ002>004. MD...None. MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ431. Small Craft Advisory until 6 PM EDT Tuesday for ANZ450>455. && $$ SYNOPSIS...DeSilva/Fitzsimmons NEAR TERM...Fitzsimmons/Gorse/OHara SHORT TERM...Fitzsimmons LONG TERM...Fitzsimmons AVIATION...Fitzsimmons MARINE...Gorse TIDES/COASTAL FLOODING...

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