textproduct: Philadelphia/Mt Holly

SYNOPSIS

High pressure builds in tonight and Thursday. A weak cold front moves through during Friday, which then stalls near Delmarva on westward. Low pressure along this front tracks near our area Friday night into Saturday, then high pressure builds in for Sunday. A cold front crosses our area later Monday followed by high pressure gradually arriving during Tuesday. More unsettled for the middle of next week.

NEAR TERM /THROUGH THURSDAY/

Some spotty drizzle lingering across southern NJ this afternoon continues to gradually dissipate. Northeast winds persist, keeping it cloudy and cool.

High pressure initially centered over the lower Great Lakes this evening will drift eastward towards New England by early Thursday. Meanwhile a frontal boundary will linger near Delmarva with some weak impulses moving through aloft in the upper level flow. This will tend to keep skies mostly cloudy, however it should remain mainly dry. The exception will be across Delmarva where there could be some spotty drizzle. Overnight lows will vary from the upper 20s over NE PA and NW NJ to the 35 to 40 degree range over Delmarva as well as SE PA and adjacent portions of southern NJ.

High pressure will ridges in more prominently during the day Thursday. A light northeasterly low-level flow in place along with surface high pressure may keep quite a bit of cloud cover in place, especially across the southern half of the region. That said, breaks in the clouds are possible across the rest of the region. While some sprinkles cannot be ruled out across Delmarva, the area should be precipitation-free. Afternoon temperatures will be in the mid 40s to mid 50s.

SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/

High pressure will slide east off the coast Thursday night, with warm advection bringing clouds back to the region. Lows in the 30s north, 40s central and south.

Wave of low pressure moving east toward the region will keep it pretty cloudy on Friday. However, warm advection precip may yet hold off until evening, but have slight chance to low chance POPs late in the day. Despite clouds, expect highs to rise back into the 50s for most of the area, except 40s Poconos and near 60 southern Delaware.

Most guidance has rain, albeit light, spreading eastward across the region by Friday night as the aforementioned weak wave moves almost straight toward us. An approaching cold front from the northwest and associated upper trough may try to divert the system more across our southern zones, while a later arrival of said front/shortwave may cause it to veer further north, but for now have likely to categorical POPs most of the CWA except far north. Lows 30s Poconos but 40s pretty much everywhere else... near 50 immediate coast.

System pulls eastward out to sea on Saturday, with any rain early ending and clouds breaking for some sun toward evening as a cold front shifts southward across the region. That said, the wind flow doesn't look especially strong so the low level moisture may struggle to be eroded away. Highs similar to Friday.

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/

High pressure builds eastward into the region Saturday night and mostly remains in control through Monday night as it slowly builds eastward, eventually passing off the New England/Mid-Atlantic coast. A weak front might spark a few showers Sunday evening, but odds look pretty low on this. Cold advection push will be noticeable Saturday night and Sunday, with lows in the 20s and low 30s, followed by highs in the 40s to low 50s. Temps moderate slowly thereafter, with lows mostly above freezing (but still 30s) on Sunday night and highs mostly in the 50s Monday, near 60 Delmarva. A still milder night is likely Monday night just ahead of the next system, with lows in the mid 30s to low 40s.

Some guidance is faster than others as far as spreading rain into the region with the next system, which will be a low pressure heading northeast through the Mid-west towards the Great Lakes Tuesday and Wednesday, but most guidance has rain across the region Tuesday night. Highs on Tuesday may end up a smidge warmer than Monday if the rain is delayed, but a milder night is likely with the rain on Tuesday night, with lows mostly 40s, near 50 coast and southern Delaware.

Guidance is also a little uncertain on when rain ends Wednesday, but most models have it out of here by day's end. A mild day looks likely as there is no initial push of cool air behind Tuesday night's system, with highs likely to be near or above 60 in much of the region.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Rest of today...Lingering IFR ceilings gradually improve to MVFR by mid afternoon with VFR possible later in the afternoon. North/northeast winds 5-8 knots. Moderate confidence.

Tonight...Becoming mainly VFR through the evening except around MIV and ACY where MVFR cigs could persist longer. Winds generally north to northeast around 5 knots.

Thursday...VFR. Winds veering from the NE to SE through the day, around 5 kts or less. High confidence.

Outlook...

Thursday night...VFR likely.

Friday...VFR likely most of day, but sub-VFR possible with rain possibly arriving late.

Friday night...Sub-VFR with rain likely.

Saturday...Starting sub-VFR with lingering rain possible, then VFR returning.

Saturday night through Monday...VFR likely.

MARINE

Small Craft Advisory in effect for portions of the southern coastal waters south of Great Egg Inlet to Fenwick Island, DE, including the lower Delaware Bay. Wind gusts up to 25 kts from the NE to NW are possible this afternoon and into the early evening. Overnight, winds diminish to around 10 kts generally out of the north through Thursday. Seas remain 2-3 feet.

Outlook...

Thursday night through Friday night...Sub-SCA likely. Rain likely Friday night.

Saturday...SCA possible with gusts up to around 25 kts.

Saturday night through Monday...Sub-SCA conditions likely.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 9 PM EST this evening for ANZ431- 453>455.