Area forecast discussion National Weather Service Baltimore Maryland/Washington District of Columbia 548 am EDT Friday may 24 2013 Synopsis... a cold front has moved offshore. An upper level low will reside over the area today...and then Canadian high pressure will build overhead for the Memorial Day weekend. && Near term /until 6 PM this evening/... as of 07z...cold anafront across the central mid-Atlantic. Precipitation has pushed to the Eastern Shore with light westerly flow across the balt-wash metropolitan...gusty northwesterly flow over the Potomac Highlands...with light precipitation and cooler conditions over the Allegheny plateau. An upper trough axis is evident as the back edge of a cloud shield over northwestern Ohio. The cold front and upper trough/developing into a closed upper low will swing east through the central middle-Atlantic today. This cold core trough/low will bring scattered showers to the area late this morning into the overnight. Expect northwesterly flow with gusts 30 to 35 miles per hour...mostly cloudy skies...and maximum temperatures low to middle 60s. && Short term /6 PM this evening through 6 am Saturday/... low/trough takes on a negative tilt tonight which will shunt the low and related precipitation off the middle-Atlantic coast by daybreak Saturday. Clearing behind the system...along with continued cold air advection will make for a chilly night by late may standards. Min temperatures low to middle 40s in the suburbs (with wind chills in the upper 30s)...around 50f in urban and near shore locales. West of the Blue Ridge...expect upper 30s to low 40s. A freeze warning is in effect for along and west of the Allegheny Front where low 30s are expected. Downsloping flow should actually moderate temperatures at kw99 and kcbe overnight. Wind chills in the mountains middle to upper 20s. && Long term /Saturday through Thursday/... high pressure over the area for the weekend. If mem day weekend is the "unofficial start of summer" then Summer is off to a pretty fine start - but maybe not for swimming. I suspect pool water may be a bit on the cool side - if you go to our web Page and look at the temperature graphs for 2013 you see that we've had a fair amount of average or below average temperatures since Mar..and the coming ngts will do nothing to help water temperatures. Highs Sat in the mu60s...then slowly warming to the m70s by Monday. Lows Sat night ranging from the m30s in The Highlands to a50 on the western shore of the ches Bay. Most of the region will drop to the 40s Sat night...then a little warmer each of the following ngts of the long weekend. By Tuesday the region will begin a warmup which really will make temperatures feel Summer-Lake for the 2nd half of the weak. High pressure will move off the CST allowing the heat pump to turn back on in the middle Atlantic. Tuesday should aprch 80 for highs...and then climbing a few degrees each day. By Friday region should see plenty of u80s. Not a lot to grab onto regarding precipitation forecast in the weak ahead. Most likely during the 2nd half of the weak there'll be afternoon scattered convctn forming over the mountains && Aviation /10z Friday through Tuesday/... patchy fog before sunrise with a cold front moving east through daybreak. Northwesterly flow with gusts 25 to 30 knots in the wake of a cold front. Near MVFR ceilings and scattered showers this afternoon under an upper low. Gusts continue overnight 20 to 25 knots though ceilings will rise above 5 kft. In the xntd VFR cnds are expeceted during the majority of the time Sat-Tue. && Marine... northwesterly flow with gusts 25 to 30 knots late this morning through tonight as an upper low persists over the region and surface high pressure builds. Small Craft Advisory in effect. Chance for brief gales this evening. Portions of the waters could xprnc Small Craft Advisory level winds Sun afternoon. && Lwx watches/warnings/advisories... District of Columbia...none. Maryland...freeze warning from 2 am to 8 am EDT Saturday for mdz501. Virginia...freeze warning from 2 am to 8 am EDT Saturday for vaz503. WV...freeze warning from 2 am to 8 am EDT Saturday for wvz501-503- 505. Marine...Small Craft Advisory until 6 PM EDT Saturday for anz530>543. && $$ Products...baj/Woody!