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Area forecast discussion 
National Weather Service Caribou ME 
944 PM EDT Sat Jul 5 2008 


Synopsis... 
high pressure will remain across the region overnight and Sunday. A 
cold front from Quebec will approach the region on Monday and move 
into the state on Tuesday. Another stronger cold front will 
approach from the west Tuesday night and cross the state on 
Wednesday. 


&& 


Near term /through Sunday/... 
conditions continue from previous forecast. Expect mainly clear 
skies tonight. With warmer temperatures tonight and light winds, 
overnight lows to remain mainly in the 50s...with some upper 40s 
in higher locations. Fog has begun to form over the coastal 
waters. Expect that it will work its way into downeast Maine 
around 06z...and begin to dissipate with sunrise. 


Bermuda high builds northward Sunday producing a warm moist 
southwesterly flow across the region on Sunday. Most locations 
will warm into the middle 80s for highs on Sunday except along the 
coast where onshore flow will keep temperatures in the 70s. Strong 
middle level subsidence inversion from building upper ridge will keep 
cumulus coverage less than today allowing for plenty of sunshine 
across the state on Sunday. As southerly flow over the waters increase 
Sunday, expect stratus and fog to develop offshore Sunday 
afternoon and move onshore Sunday evening as low levels start to 
cool. Used a blend of the guidance for temperatures. 


&& 


Short term /Sunday night/... 
main concerns will be stratus and the potential for fog especially 
downeast and the coast Sunday night into early Monday and the 
potential for convection on Tuesday. 


Decided on a blend of the NAM/GFS & sref for the probability of precipitation and quantitative precipitation forecast and 
took a blend of the NAM and GFS for the sky and winds. 


Concern is there for the development of stratus and fog Sunday 
night into early Monday as weak S flow develops west/plenty of low level 
moisture being advected into the coast and downeast regions. The 
latest BUFKIT from the NAM and even the sref indicate this to 
happen. The GFS is not as aggressive. Decided to bring 90%+ sky 
conver and areas of fog into the aforementioned areas. Further 
north...sky conditions should remain mostly clear...but this will need 
to be watched to see if later mld runs point to the stratus/fog 
edging further north. 


Monday into Tuesday will be warm and increasingly humid. Pulled 
back on mention of thunderstorms Monday as middle-levels will be capped and 
forcing is very week. The better chance for thunderstorms will come Tuesday 
as a frontal boundary sets up across the County Warning Area and that cap weakens. 
Decision here was to include thunderstorms Tuesday afternoon as model 
soundings do show sb convective available potential energy to hit 1500+ j/kg early and some decent 
shear from 0-6 km of 30 kts noted. One thing to note against the 
prolonged nature of convections is that sounding profiles show 
cap strengthening again which could diminish activity by middle to 
late afternoon. 


Temperatures were a blend of the guidance and then manually 
adjusted especially for the coast as south-southwest flow will keep temperatures down 
some both Monday and Tuesday. 


&& 


Long term /Monday through Saturday/... 
confidence level building west/the potential for a significant 
convective event on Wednesday. 


Decided to follow the European model (ecmwf) west/synoptic features and used the gmos 
as the background and then adjusted accordingly. European model (ecmwf) has been 
consistent west/the cold front coming through the County Warning Area on Wednesday 
and bring primary low well north of the County Warning Area through southern Quebec. HPC 
has leaned in this direction as well. GFS has 998mb low moving in 
along a stalled frontal boundary on Wednesday into Wednesday 
night. Looks like the GFS could be suffering from convective 
feedback. We'll see if the other models such as the NAM and 
European model (ecmwf)/UKMET pick up on the low. 


Per telco W/gyx...went west/high chance probability of precipitation Wednesday into Wednesday 
night and carried thunderstorms. Atmos does look like it could be primed 
for a significant convective event. Precipitable waters  projected to go above 
2... above 1500 j/kg and good directional/speed shear. 
Still plenty of time to assess this west/later model runs. 


Front expected to clear the coast by Thursday west/the upper trough 
still hanging back. Carried chance probability of precipitation for Thursday as upper trough is 
forecast to cross the region by Thursday evening. 


High pressure is then prognosticated to build in briefly for Friday west/near 
normal temperatures. 


Gmos temperatures were followed closely. Some adjustments were 
done to the probability of precipitation field especially Thursday night into Friday to bring 
them down from chance category as high pressure builds in from the SW. 


&& 


Aviation /02z Sunday through Thursday/... 
near term: high pressure will provide mainly clear skies tonight 
and Sunday. 


Shorter term: VFR going to MVFR and IFR later Sunday night into 
early Monday for kbgr and kbhb west/weak S flow. Northern taf sites should 
stay VFR. VFR pretty much Monday into Tuesday west/some fog 
potential again Monday night which could lower visibilities to MVFR status. 
Frontal boundary expected to cross the region on Wednesday will 
lead to MVFR conditions W/tstms. 


&& 


Marine... 
near term: light and variable winds tonight and early Sunday will 
increase from the SW Sunday afternoon. Fog has begun to develop 
along the downeast coast and over the coastal waters. Expect the fog to 
be dense in areas. The fog will begin to dissipate with sunrise. 
The continued SW flow will allow fog and stratus to develop over 
the waters again during Sunday afternoon. 


Shorter term: not expecting any headlines at this time. Some concern is 
there that seas(swell) could come west/in Small Craft Advisory limits late Wednesday 
into early Thursday west/continued south-southwest flow and the approach of the 
front. At this time...backed away from wnawave as it has been running at 
least 2 feet too high. Therefore...brought seas up by the end of the 
period to west/in 6 feet but this is for the outer marine zones. 


NAM/GFS winds looked like a good fit into Tuesday and then 
followed west/the gmos and adjusted the speeds down especially at night. 
10-15 kts should do TI at this time. 


&& 


Car watches/warnings/advisories... 
ME...none. 
Marine...none. 


&& 


$$ 


Near term...Norton/Foster 
short term...allegretto 
long term...Hewitt 
aviation...Foster/Norton 
marine...Foster/Norton 

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