Area forecast discussion 
National Weather Service Gray ME 
1201 am EDT Thursday Jun 20 2013 


Synopsis... 
high pressure will build east across the region through Thursday, 
then slide offshore Friday...and sit over the western Atlantic 
into early next week. This will allow southwest flow to develop 
across New England...transporting warmer and more humid air into 
the region Sunday into early next week. 


&& 


Near term /until 6 am Thursday morning/... 
1155 PM...just some minor tweaks to temperatures overnight...mainly to go 
a degree or two warmer in the north...which keeps mins mainly in the 
upper 30s here. Dew points mainly around or 40 or in the low 40s...so fog 
looks like a better bet than frost in the mountain valleys...although 
could see a few pockets of frost in those colder valleys. 


7 PM update...no major changes to the going forecast. Skies are 
clear and will continue that way overnight. With calming winds...the 
conditions will be ripe for radiational cooling...and therefore 
some chilly overnight lows. Some patchy frost possible in interior 
valleys...along with River Valley fog. 


Previously... 


At 18z...a 1023 millibar high was centered near Lake Huron. GOES 
visible imagery showed several areas of fair weather cumulus 
across the area. Middle afternoon temperatures were within a degree 
or two either side of 70f. Clouds will melt away by evening with 
the loss of daytime heating. Light winds and clear skies under the 
building high will produce relatively cool readings overnight with 
lows in the 40s with upper 30s across the mountains...where 
widely scattered frost is possible in the normally colder valleys. 
Mitigating frost potential as well will be fog and stratus 
development overnight. 


&& 


Short term /6 am Thursday morning through Thursday night/... 
after a cool start sunny skies under the high will allow 
temperatures to rebound into the 70s with a few 80 degree readings 
possible over southern interior sections. The light synoptic flow 
will allow for winds to turn onshore by early afternoon with 
developing sea breeze. 


The high shifts offshore by late Thursday and opens the door for 
the cold front over Quebec to sag southward towards the 
international border by Friday morning. Expect clouds to increase 
across the mountains/foothills and northern New Hampshire in the 
predawn hours...with any showers limited to far northern areas 
through dawn. 


&& 


Long term /Friday through Wednesday/... 
have used a blend of the European model (ecmwf) and previous official forecast for 
this period. A warm front will approach the area Friday. As winds 
aloft become parallel to front it will then stall in the vicinity of 
the region over the weekend into next week. This will result in a 
warm and at times unsettled pattern with the threat of diurnal 
convection. With a west northwest flow aloft expect a few short 
waves to enhance shower and thunderstorm threat. As is often the 
case with this type of setup...timing these shortwaves this far in 
advance is a challenge. At this time the European model (ecmwf) has shortwaves 
crossing the region next Monday and again next Wednesday. Have 
upped probability of precipitation slightly on those days to account for this. 


&& 


Aviation /04z Thursday through Monday/... 
short term /through 12z Fri/...fog and stratus possible tonight at 
kleb and khie...otherwise expect VFR. 


Long term /12z Friday through 23z Monday/...VFR-MVFR conditions will 
be prevalent with areas of IFR in any shower and thunderstorm 
activity. As the air mass becomes more humid areas of night time 
br/fog will be possible. 


&& 


Marine... 
short term /through Thursday night/...waters will be quiet as 
seas/winds remain below Small Craft Advisory levels under building surface high. 


Long term / Friday through Monday night/...winds to stay below 
Small Craft Advisory levels. Seas will build as a SW flow develops although this 
could become more of a swell. 


&& 


Gyx watches/warnings/advisories... 
ME...none. 
New Hampshire...none. 
Marine...none. 


&& 


$$ 
Synopsis... 
near term...cempa 
short term... 
long term... 
aviation... 
marine...