Area forecast discussion 
National Weather Service Caribou ME 
106 am EDT Thursday may 23 2013 


Synopsis... 
a warm front will slowly progress north across the region overnight 
and Thursday. Low pressure will lift to our west on Thursday then 
gradually push a cold front across the area Thursday night into 
Friday. A wave of low pressure will move northeast along the front 
with rain expected Friday and into the weekend.&& 


Near term /through today/... 
1 am PM update: added the chance of thunderstorms for late tonight 
over northern areas. Also adjusted mins down a few degrees based 
on current trends. Finally, lowered probability of precipitation a bit for Thursday 
morning as most areas should see a respite before showers and 
thunderstorms develop later in the day. 


Previous discussion: whats left of the convection over New Hampshire and Massachusetts 
may make it into portions of downeast Maine later this evening in 
the form of some remnant showers as the activity weakens in the 
more stable air across our area. Have indicated some higher probability of precipitation 
later this evening across downeast Maine to account for this 
mainly after 8 PM. Otherwise...it will continue cloudy across the 
region overnight as deep layer moisture continues with moist 
southwest flow aloft and moist southerly flow in the low levels 
continuing. Expect the chance for showers across the region 
overnight. Low temperatures will not fall that much from current 
late afternoon readings with abundant cloud cover and moisture in 
place. 


On Thursday an upper level trough will continue to slowly migrate 
east across the great region with a broad southwest flow 
continuing aloft. At the surface...low pressure is expected to 
slowly track northeast through southern Quebec as it pulls a cold 
front east. The front will be slow to move east as it parallels 
the flow aloft. There will be an increasing chance for showers and 
thunderstorms later Thursday morning and Thursday afternoon as the 
front moves slowly toward the region from the west. Big question 
on Thursday will be potential for any convection to develop in 
advance of the front Thursday afternoon. The GFS continues to be 
more aggressive in destabilizing things during Thursday afternoon 
and continues to show sb convective available potential energy in the 500-1000j/kg range mainly 
across northern and western sections. There is some shear in the 
0-6 km layer on the magnitude of 30 to 40 kts. Again the big 
question will be how much instability we see and this will be 
dependent on any breaks in the clouds that might occur on 
Thursday. Still looks like the best chance for seeing any thunder 
will be across western areas where low level flow will become more 
southwest in advance of the front later in the day. Have indicated 
the highest probability of precipitation for showers and thunderstorms across northern and 
western sections during Thursday. Current thinking is any storms 
would be sub severe but any storms could have some gusty winds. 
Also...included the mention of heavy rain in any thunderstorms 
with precipitable waters  running 1 to 1.5 inches. Decided to keep the mention of 
thunders out of eastern Maine since thinking is things should 
remain more stable here with marine layer in place. Have leaned 
closer to MOS mav nos for high temperatures on Thursday. 


&& 


Short term /tonight through Saturday/... 
a very cool and wet weather pattern will drive our weather through the short term 
period... the entire 12z model suite is in general agreement west/ 
overall trends during the period though some diffs exist in the specific 
details. A slow moving frontal boundary is forecast to enter western/northwestern areas 
Thursday night and slowly push sewrd across the forecast area later Thursday night through Friday 
as a series of weak surface waves lift NE along this boundary. This front 
is forecast to finally stall just east and southeast of the forecast area by later Friday 
night/Erly Sat as a stronger area of low pressure lifts newrd up along 
this boundary west/ most models positioning surface low pressure over the gom by 
12z Sat. This low is then expected to wrap up and drift slowly NE 
through Sat and the remainder of the upcoming Holiday weekend. 
Unfortunately...very wet/cool and dreary conds will result west/ 
Little Hope of any major deviations from these trends at this time. 


Will introduce likely to Cat probability of precipitation north and west Thursday evening and spread these 
high probability of precipitation sewrd through Thursday night west/ likely to Cat probability of precipitation continuing right through 
Sat for all but our far northwestern areas. Will also keep mention of 
thunder through the evening hours west/ this threat expected to mostly 
diminish by mdngt. 


Very chilly air will follow the frontal boundary by Friday and this 
combined west/ abundant clouds and precipitation will result in forecast highs 
only in the lower 50s north on Friday and only in the upper 40s across 
the north on Sat... 


Precipitation amounts during this period should range from around .75 far northwest 
to between 1.0 and 1.5 inches across the remainder of the area. 


&& 


Long term /Saturday night through Wednesday/... 
low pressure moving up the New England coast will bring rain 
Saturday night through Sunday night. Temperatures will be chilly 
with highs in the low to middle 50s. Actually...temperatures could 
end up being lower without some brief breaks in the clouds and 
rain. This will be a slow-moving cut-off low. By Monday 
morning...the low will be over the area and showers will persist 
Monday. Highs will be in the upper 50s to low 60s. High pressure 
will finally build Monday night. This will produce dry conditions 
until late week with temperatures rising through the period. 
Highs are expected to return towards 70f by Wednesday. 


&& 


Aviation /05z Thursday through Monday/... 
near term: widespread MVFR ceilings early this evening will give way 
to widespread IFR ceilings overnight. IFR conditions will continue 
into Thursday but conditions should give way to MVFR across the 
northern terminals by Thursday afternoon in showers and scattered 
thunderstorms. IFR conditions may continue into Thursday afternoon 
at kbgr/kbhb terminals in low clouds. 


Short term: poor flying conds are expected through much of the period as 
a slow moving frontal system crosses the region Thursday night/Friday and 
stalls just east/southeast of the area as several significant lows lift 
newrd up along this boundary. Expect widespread IFR/MVFR through the period west/ 
only some gradual improvement possible by Monday... 


&& 


Marine... 
near term: wind/seas will remain below Small Craft Advisory levels through tonight and 
then increase to Small Craft Advisory levels during Thursday. A Small Craft 
Advisory remains in effect beginning noon time Thursday. Patchy 
fog will reduce visibility to 1 to 3 nm in fog through Thursday. 


Short term: a frontal boundary will gradually mv into the waters late 
Thursday night and Friday and then stall west/ several surface low pressure systems 
forecast to lift NE along this stalled frontal boundary. Persistent srly 
winds ahead of this system will help elevate seas west/ generic Small Craft Advisory 
conds expected into Friday. Winds will abate as this frontal boundary 
stalls over the waters but expect a prolonged period of elevated seas 
to persist into the weekend. Current Small Craft Advisory headlines into Friday will 
likely need to be extended... 


&& 


Car watches/warnings/advisories... 
ME...none. 
Marine...Small Craft Advisory from noon today to noon EDT Friday for 
anz050>052. 


&& 


$$ 
Near term...fitzsimmons/Hewitt 
short term... 
long term... 
aviation...fitzsimmons/Hewitt/ 
marine...fitzsimmons/Hewitt/