textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

The Small Craft Advisory was expanded to include all ocean zones off the NJ and DE coast and also extended to 6 PM Tuesday.

A climate section has been added to list the high temperature records for this Wednesday.

KEY MESSAGES

1. Continuing breezy and dry this afternoon with some fire weather concerns.

2. A roller coaster temperature pattern resumes during the upcoming week, with significant warming through mid-week followed by a return to cooler weather thereafter, along with multiple chances of showers and perhaps thunderstorms.

DISCUSSION

KEY MESSAGE 1...Continuing breezy and dry this afternoon with some fire weather concerns.

High pressure has moved off the coast this afternoon with breezy SW winds developing in its wake in the return flow. While relative humidity levels are not as low as yesterday, they are getting down into the 25 to 35 percent range where they should stay through much of this afternoon. This is due to dry air getting mixed down from aloft. We'll also have winds this afternoon continuing to gust 20 to 25 mph. Recent rainfall and a short period with a combination of breezy winds and low RHs are the limiting factors for today's threat. In collaboration with our fire weather partners, we did issue a Special Weather Statement for fire weather just for our MD eastern shore counties. This is in effect until 7 PM. By this time winds will be diminishing and RH values will be increasing.

Continuing south/southwest flow will bring more moisture in with time so no further fire weather concerns are expected after today.

KEY MESSAGE 2...A roller coaster temperature pattern resumes during the upcoming week, with significant warming through mid- week followed by a return to cooler weather thereafter, along with multiple chances of showers and perhaps thunderstorms.

High pressure will remain situation off the Eastern Seaboard through mid-week, with southwesterly flow setting up over the area for multiple days. This will lead to a warming trend through Wednesday. By Tuesday, temperatures are likely to rise into the 70s across most of the area. Tuesday night's lows look to be in the low 60s for most, setting the stage for a very warm Wednesday, with highs in the upper 70s and lower 80s, with cooler temperatures in the Poconos and near the coast. If enough sunshine occurs and the showers hold off longer, some inland areas could challenge their record high temperatures for April 1st (Wednesday).

Scattered showers and perhaps a few rumbles of thunder will be possible beginning during the day Monday and continuing through Tuesday morning as a few weak mid-level impulses move through, with PoPs generally in the 30-50% range for most of the area. A stronger cold front is expected to move through the area Wednesday evening into Wednesday night, with more meaningful shower and storm chances. Timing discrepancies remain, though it appears that showers and storms will spread from northwest to southeast across the area beginning Wednesday afternoon and continuing through Wednesday night. Model guidance is indicating weak to moderate instability, with MLCAPE of 500-1000 J/kg. While winds aloft will be on the weaker side, a few stronger storms cannot be ruled out, especially near peak heating on Wednesday when instability is maximized. Strong to perhaps locally severe winds would be the primary hazard with any stronger storms.

After the cold front passes through the area, temperatures will cool back down into the 60s for Thursday. Indications are that the cold front will eventually stall and perhaps lift back north a bit, remaining near or just south of the area into the weekend. This will continue to provide an unsettled pattern with shower chances each day, as well as a tricky temperatures forecast. High temperatures late this week into the weekend look to be in the low to mid 60s north of the front and 70s south of it, with lows in the 40s north and 50s south. As of now, it appears the front is most likely to set up from east to west roughly through the Philly metro, though this is subject to change in subsequent forecasts.

AVIATION /19Z SUNDAY THROUGH FRIDAY/

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

This afternoon...VFR. Southwest winds 10 to 15 gusting 20 to 25 knots. High confidence.

Tonight...VFR. Winds diminishing early around 23z to 5-10 knots out of the SW. LLWS expected overnight with a brisk low-level jet overhead. High confidence.

Monday...VFR. Southwesterly winds around 10 to 15 with gusts up to around 20 kt. High confidence.

Outlook...

Monday night through Tuesday...Primarily VFR. Sub-VFR conditions are possible at times in showers.

Tuesday night...VFR.

Wednesday through Wednesday night...A period of sub-VFR conditions is expected in showers and storms. This is most likely late Wednesday afternoon and into Wednesday night.

Thursday...Primarily VFR. Sub-VFR conditions are possible at times in showers.

MARINE

A Small Craft Advisory is in effect beginning at 4 PM for all of our ocean zones as SW winds will generally be gusting to around 25 knots by this time. Winds may diminish slightly for a time tonight and then come back up again Monday so the Small Craft Advisory runs through the day Monday and beyond. Seas 2 to 4 feet this afternoon increasing to 4 to 5 feet by later Monday.

Outlook...

Monday night through Wednesday...SCA conditions expected, with a period of low-end gales not out of the question Tuesday night. Southwesterly winds 10-15 kt with gusts to 20-25 kt and seas 3-6 feet Monday night. Winds and seas will increase through the day Tuesday, peaking Tuesday night at 20-30 kt with gusts as high as 35 kt and seas 4-8 feet. Winds and seas are expected to remain elevated on Wednesday but may decrease slightly.

Wednesday night through Thursday...SCA conditions likely with winds shifting easterly at 15-20 kt with gusts to 25 kt and seas 4-6 feet.

CLIMATE

The warmth is forecast to surge into our area during the first half of this week, with it peaking on Wednesday. Given the current forecast, some inland areas could challenge their record high temperatures on Wednesday, April 1st.

Location Record High 4/1 -------- --------------- ACY Atlantic City, NJ80/1978 PHL Philadelphia, PA81/1978 ILG Wilmington, DE 81/1978 ABE Allentown, PA84/1978 TTN Trenton, NJ81/1986 RDG Reading, PA82/1917 GED Georgetown, DE80/1979 MPO Mount Pocono, PA81/1998 55N AC Marina, NJ72/1955

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ450>455.