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NWS Discussion
			
				

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. 


&& 


$$ 
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