textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated the aviation section for the 00Z TAFs.

KEY MESSAGES

1. A slow moving cold front approaches tonight and crosses the area Friday.

DISCUSSION

KEY MESSAGE 1...A slow moving cold front approaches tonight and crosses the area Friday.

An upper-level trough pivoting over the Great Lakes region will continue to slowly track eastward through tomorrow, before the upper low moves overhead on Saturday. At the surface, this translates to a slow moving cold front approaching the region this evening, before slowly moving overhead tonight and stalling across parts of our area tomorrow.

Isolated to widely scattered showers this evening will become more widespread overnight. Since there has been a lack of rain for our area the past 2 to 3 weeks, the showers are rather beneficial. Rainfall amounts will vary across the area with lower amounts N/W (a tenth to three- quarters of an inch) while southern NJ and Delmarva will have higher totals of 1 to 2 inches. The rain is expected to occur over a long enough period to preclude any flooding concerns. A few thunderstorms may develop this evening or overnight, but the chances of this are low. The front stalls for a period tomorrow morning before resuming a SE push during the afternoon. This will promote the higher QPF totals for those areas. Conditions will gradually improve throughout the day tomorrow with mostly fair weather for areas N/W. There will be slower improvement for S/E areas. For the I-95 corridor, conditions are forecast to improve during the afternoon. The SE areas may not see any substantial improvement until the evening hours.

The cold front departs offshore Friday night, with dry conditions returning for much of the area. However, guidance indicates an upper- low will track eastward across northern portions of the area on Saturday. This will lead to a lingering chance for some light rain north of I-78, with the highest chances (40-50%) across the Poconos and far northern NJ. By Sunday morning, the upper-low will be east of the area bringing a return of dry conditions to the region along with cooler temperatures.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

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

Tonight...Lowering CIGs/VSBYs as rain showers increase in coverage. Conditions gradually lower to MVFR to IFR across the terminals overnight. Due to the low potential of any thunderstorms, thunder has remained out of the TAFs. South to southwest winds 5 to 10 knots with periods of light and variable at times. Low/medium confidence.

Friday...Conditions gradually improve from NW to SE. For KRDG/KABE, VFR is probable by late morning. The I-95 terminals are forecast to become VFR during the afternoon around 19Z. The KACY/KMIV terminals will be the slowest to improve with MVFR to IFR conditions lingering into the evening. Northwest to north winds around 5 to 10 knots. Medium confidence.

Outlook...

Friday night...Restrictions will remain possible through much of the night in rain and low clouds, particularly at the near- coast terminals.

Saturday through Saturday night...Primarily VFR. Brief restrictions will be possible for the Lehigh Valley terminals in rain or low clouds.

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

MARINE

Winds and seas will continue to build into tonight with the Small Craft Advisory remaining in effect for all of the Atlantic coastal waters until 5 AM. As the weak low arrives Friday, the winds will lessen and seas will diminish. Rain showers move through tonight through Friday with a slight chance for an isolated thunderstorms.

Outlook...

Friday night...No marine headlines currently anticipated with winds under 25 kt and seas under 5 feet. Visibility restrictions possible in periods of rain.

Saturday through Tuesday...Advisory conditions will be likely at times with west-northwest winds 15-20 kt gusting to 25-30 kt. Highest confidence in advisory conditions is currently late Saturday into early portions of Sunday and again on Monday. Seas generally 4- 6 feet through the period.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 5 AM EST Friday for ANZ450>455.