textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

A Small Craft Advisory was issued for ocean zones north of Cape Henlopen, beginning this afternoon and continuing through the day tomorrow.

Added a key message for fire weather concerns today.

Updated aviation discussion.

KEY MESSAGES

1. Another day of breezy and dry conditions with some fire weather concern.

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 rain.

DISCUSSION

KEY MESSAGE 1...Another day of breezy and dry conditions with some fire weather concern.

High pressure currently overhead will move offshore today, with south/southwesterly return flow setting up. While RHs will not be as low as yesterday, there is still a good amount of dry air aloft that will be tapped into via efficient mixing. Overall fire weather concern is not as high as yesterday, but will coordinate with fire weather partners this morning to see if any Special Weather Statements are needed. RHs will be around 25-35% with a period of wind gusts in the 20-25 MPH range this afternoon. Recent rainfall and a short period with a combination of breezy winds and low RHs are the limiting factors for today's threat.

Consecutive days of south/southwest flow will bring more moisture in, and 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 rain.

Warming trend continues through mid-week with southwesterly flow enhancing as high pressure moves out to sea and warm front advances north. Still possible a little rain or a few showers occurs with the warm front, most likely Monday night, but otherwise temps should steadily elevate with many areas likely topping 80 by Wednesday. Then cold front still expected to push southeast with a shower/t-storm risk (still watching any severe potential) followed by much cooler weather Thursday, with temps back to the 50s north and 60s south. As the front stalls and low pressure waves start riding eastward along it, rain chances will continue, with the best chance still looking like Friday. That said, the latest guidance has been more restrictive with the cold air bleed from the north, so the risk of wintry weather appears to have diminished. A front lying nearby may result in large gradients over the region by Saturday, with 50s north and east of Philly and 70s south and west.

AVIATION /10Z SUNDAY THROUGH THURSDAY/

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

Today...VFR. Winds pick up out of the south/southwest around 13z-14z around 5 to 10 kt, increasing to 10 to 15 kt with gusts 20 to 25 kt after 17z. Winds diminish around 23z. High confidence.

Tonight...VFR. Winds south/southwest around 5 to 10 kt. LLWS expected overnight with a brisk low-level jet overhead. High confidence.

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

Outlook...

Monday night through Tuesday night...VFR likely.

Wednesday and Wednesday night...Sub-VFR possible due to potential showers and thunderstorms.

Thursday...Sub-VFR possible due to chance of rain.

MARINE

A Small Craft Advisory is in effect beginning at 4 PM for ocean zones north of Cape Henlopen as gusts out of the southwest around 25 kt and seas of 3 to 5 feet are expected. The Small Craft Advisory goes through the day tomorrow for those zones.

For Delaware Bay and coastal waters south of Cape Henlopen, sub-SCA conditions are expected. Winds today and tonight will remain below 25 kt with seas 2 to 4 feet on the ocean. Coastal waters south of Cape Henlopen may need to be added to the SCA tomorrow as winds inch towards 25 kt, but confidence was not high enough to issue an SCA for that zone yet.

Outlook... Small Craft Advisory conditions may persist on the ocean waters Monday night through at least mid-week with strengthening south-southwest flow ahead of a cold front, which may approach low-end gales at times. Lower winds expected on the bays. Seas on the oceans of 4-6 feet Monday night may gradually build up to 6-10 feet Tuesday night and Wednesday. Winds shift northwesterly but may still occasionally gust 25-30 kts Wednesday night and Thursday, with seas still remaining elevated on the ocean waters. Some showers and thunderstorms are also possible with the cold front.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 4 PM this afternoon to 6 PM EDT Monday for ANZ450>454.