Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 300712
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
312 AM EDT Tue May 30 2017

.SYNOPSIS...
The moist onshore flow will continue along the coast as well as
much of Maine today as a ridge of high pressure shifts well
offshore. An occluded front will slide east and produce a few
showers and isolated thunderstorms later today and tonight as it
crosses the area. On Wednesday and Wednesday night...a cold front
will sweep east and cross the region accompanied by showers and
thunderstorms. a surface trough will cross the area on Thursday
and may touch off a few mountain showers. Low pressure and a
trailing frontal system will cross the region Friday and Friday
night with a few showers.

&&

.NEAR TERM /THROUGH TODAY/...
At 06z...a 1023 millibar was centered vicinity of New
brunswick. A 998 millibar low was over northern Ontario with a
trailing frontal system through the Great Lakes region. NWS
Doppler radar mosaic showed scattered convection along and ahead
of an occluded front over the eastern Great Lakes. For
today...the surface high will retreat well offshore allowing the
surface flow to gradually veer to a more southerly trajectory
during the day. That will allow fog and ceilings to lift and
there could even be a few peaks of sunshine over interior
sections by afternoon. Temperatures...while still below
normal...should average five to ten degrees warmer then Monday
across the region. With the exception of any drizzle near the
coast early this morning...it`ll be a dry start to the day as we
await the approaching frontal boundary and a series of weak
shortwave impulses that will introduce an increasing chance for
showers and isolated thunder from west to east during the
afternoon and particularly the evening hours.


&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
The weakening front will cross the area tonight accompanied by
an area of showers and perhaps a rumble of thunder. We`ll see
some areas of fog and drizzle along the coast...especially along
the maine coastline. On Wednesday...we should see at least some
sunny periods with temperatures warming into the 60s and lower
70s ahead of an approaching shortwave impulse and associated
cold front. Showers and thunderstorms should develop upstream by
afternoon then sweep eastward into the region during the
afternoon and evening hours. The convection should weaken as it
encounters the strong marine influence over much of Maine.
However...from the Connecticut valley northward to the
international border area can`t entirely rule out a few
thunderstorms will strong gusty winds during the later
afternoon/early evening hours.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Upper level closed low which has been centered near the upper
Great Lakes will have meandered a little bit closer by Thursday
(but still just west) with more of an E-W dipole affect to the
height pattern. By Saturday short wave energy rounding the
system will have refocused the 500mb pattern to a more
traditionally positively tilted one...stretching from
Newfoundland back towards the northeastern CONUS. For the
upcoming week the low center will rotate into the northern
Atlantic leaving just large scale positively-tilted troughing
over our neck of the woods.

A frontal system will be in the process of crossing the area
Thursday morning with any remaining showers likely confined to
the upslope regions at that time. With downsloping westerly
winds for most of the day, we should have mostly to partly sunny
skies over the coastal plain and temperatures should warm into
the upper 60s to mid 70s for that area. Farther north lower to
mid 60s will be common in showers and dense cloud cover.

A warm front arrives from the west during the day Friday
bringing additional moisture and widespread showers back to the
area. There may be a brief window for a few thunderstorms over
southern NH and SW ME Friday as this occurs. On Saturday an
occlusion crosses the CWA from west to east by Saturday morning.
At this point the long term models begin to show placement and
timing differences with the GFS pushing the baroclinic zone well
south of northern New England and the Euro keeping it much
closer. It does look like another coastal cyclone zips by to our
south early next week...possibly impacting the region.

As far as temperatures, we will be below normal for highs and
above normal for lows.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Short Term /through Wednesday/...IFR with areas of MVFR
improving to MVFR throughout during the day. Conditions will
lower to IFR with areas of MVFR away from the coast tonight. On
Wednesday...improving to VFR throughout with areas of MVFR
during the afternoon in scattered shra and tsra.

Long Term...Improving conditions Thursday with MVFR in-SHRA for
HIE. Fog may bring periods of MVFR Thursday morning. Widespread
-SHRA Friday and Saturday with prevailing MVFR by Friday evening
 and pockets of lower conditions.

&&

.MARINE...
Short Term /through Wednesday/...Winds and seas likely to
remain below SCA levels tonight through the period.

Long Term...Winds and seas should stay below SCA criteria,
however periods of rain and fog will make for poor marine
conditions.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$
SYNOPSIS...Schwibs
NEAR TERM...Schwibs
SHORT TERM...Schwibs
LONG TERM...Hanes
AVIATION...Schwibs
MARINE...Schwibs



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