textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1. Dry and breezy conditions will result in some fire weather concerns continuing through this afternoon.

2. A roller coaster temperature pattern resumes next week, with significant warming through mid week followed by much cooler weather thereafter, along with multiple chances of rain.

DISCUSSION

KEY MESSAGE 1. Dry and breezy conditions will result in some fire weather concerns continuing through this afternoon.

High pressure over the Midwest will continue to gradually move eastward through this afternoon. A relatively tight pressure gradient will remain overhead until the high gets closer, resulting in a dry and brisk northwest flow continuing. Expect NW winds continuing to be around 15 to 20 gusting 25 to 35 mph. Winds relax quickly after sunset as the gradient weakens with the area of high pressure moving in.

Rainfall received yesterday will be the limiting factor for a critical fire weather day today. However, with RH values dropping to around 20-30% and breezy winds gusting 25 to 35 MPH, there is at least some concern for enhanced fire spread should something ignite. As a result, a Special Weather Statement for an elevated risk of wildfire spread remains in effect for our Delaware and MD Eastern Shore counties through this afternoon.

Flow turns more south/southwest tomorrow with lesser winds and higher RH values. As a result, this should be the only day of elevated fire weather concerns.

KEY MESSAGE 2...A roller coaster temperature pattern resumes next week, with significant warming through mid week followed by much cooler weather thereafter, along with multiple chances of rain.

Our high pressure system continues to move offshore Sunday night. A warm front then moves through the area Monday into Monday night. This will allow for continued warm air advection. We see an increase in clouds for Monday and Monday night. During the day Monday looks relatively dry with perhaps a spotty shower. The better potential for rain showers is Monday night with the warm front continuing to move northward, but showers still look isolated.

On Tuesday, the warm front will be to the north of the area which places us in the warm sector into Tuesday night. High temperatures on Tuesday reach into the 70s for many with some locations near 80. It will be cooler by the coast. This timeframe also looks pretty dry with an isolated shower possible for mainly areas near and NW of the I-78 corridor.

A better potential for rain showers and some isolated thunderstorms is Wednesday into Wednesday night as a cold front moves through the area. Depending on timing and how the atmospheric set up evolves, this is a time period to watch for any severe weather. Temperatures are mainly in the 70s with some locations again near 80 ahead of the front. As cold air filters in behind the front, temperatures fall into the 30s and 40s Wednesday night.

There is more uncertainty for the end of the week and into the start of the weekend. The weather pattern remains unsettled. Our cold front stalls near or just south of the area Thursday with a continued potential for rain. An area of low pressure looks to approach the region and bring more rain to the area Thursday night into Friday. Temperatures during this timeframe will generally be in the 40s and 50s during the day and in the 30s and 40s Thursday night. Rain looks to be the main precipitation type, but the higher elevations of our northern zones have the potential to be cold enough for some wintry precipitation to mix in, particularly Thursday night into Friday morning. A high pressure system will also be located to the north in Canada for the end of the week and into the start of the weekend allowing for more cooler air to filter in.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

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

This afternoon...VFR. Northwest winds around 15 kt with gusts 20-30 kt. High confidence.

Tonight...VFR. Winds quickly diminish after 00z to around 5 kt before going light and variable to calm between 03z-06z as high pressure slides overhead. High confidence.

Sunday...VFR. Winds pick up out of the south/southwest around 10 kt with gusts up to 20 kt. High confidence.

Outlook...

Sunday night through Tuesday...VFR. No significant weather.

Wednesday...Sub-VFR likely with rain showers and possible t-storms.

Thursday...Generally VFR, but sub-VFR possible in rain showers.

MARINE

A Small Craft Advisory remains in effect for all marine zones this afternoon until 5 PM as NW winds continue around 15-25 kt with gusts 25-30 kt. Seas of 3 to 5 feet expected today.

No marine headlines are expected for tonight but for Sunday south/southwest winds increase and could reach near Small Craft Advisory levels by late day. Seas of 2 to 4 feet for tonight and tomorrow.

Outlook... Small Craft Advisory conditions may develop Monday and persist through Tuesday as a warm front lifts northward, with southwesterly winds gusting 25-30 kts and seas of 5-6 feet.

Small Craft Advisory conditions likely Tuesday night through Wednesday with wind gusts of 25-30 kts and seas 6-8 feet as a cold front approaches and then crosses through the area. A period of gale conditions is possible Tuesday night into Wednesday morning with wind gusts upwards of 30-35 kt.

Small Craft Advisory conditions look to remain likely Wednesday night into Thursday with seas of 5-7 feet and wind gusts of 25-30 kts.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 5 PM EDT this afternoon for ANZ430- 431-450>455.