textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Minor POP/Weather changes. Confidence in thunder is low and was removed from TAFS and kept at slight chance in Public products.

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 troughing pivoting over the Great Lakes region slowly continues to track eastward through Friday, before the upper low moves overhead on Saturday. At the surface, this translates a slow moving cold front approaching the region on later today, before slowly moving overhead and stalling nearby through Friday.

We've already had some light rains across most areas earlier but more will arrive this evening and it'll become widespread overnight. Since there has been a lack of rain for our area the past 2 to 3 weeks, the rains are rather beneficial. Rainfall amounts will vary across the area with light 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 rains are expected to occur over a long enough periods to preclude any flooding concerns. A few tstms may develop this evening or overnight, but the chances of this are low so slight wording was included in the fcst. The front stalls for a periods Friday morning before resuming a SE push for the afternoon. This will promote the higher QPF totals for those areas. Slow improvement in weather conditions for Friday with mostly fair weather N/W and slow improvement for the Delaware Valley ny early afternoon. The SE areas may not see any substantial improvement by sunset.

The cold front departs offshore Friday night, with dry conditions returning to 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 /18Z THURSDAY THROUGH TUESDAY/

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

Rest of today... VFR or upper end MVFR with widely scattered showers. South winds 10 to 15 kts with gusts 20 kts possible. Medium confid.

Tonight... Lowering CIGS/VSBYs as showers become more common across the TAF sites. Largely low-end MVFR and IFR expected. Showers with a slight chance for TS too. Removed TS from TAFs though with confidence in occurrence rather low. South to Southwest winds 5 to 10 knots most of the time. Winds shifting to NW for KRDG/KABE towards dawn. Low/medium confid.

Friday... Slow improvement S/E (KACY/KMIV) but VFR probable by late afternoon. Earlier VFR for Delaware Valley sites with 17Z/19Z time frame possible. KRDG/KABE will have VFR much of the day. Northwest to North winds around 10 knots. Medium confid.

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 this afternoon and tonight with the SCA flag already up which will remain unchanged. As the weak low arrives Friday, the winds will slacken and seas will diminish. Showers late tonight and Friday. A slight chance for a TSTM.

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 from 5 PM this afternoon to 5 AM EST Friday for ANZ450>455.