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/
