Area Forecast Discussion
Issued by NWS Portland, ME

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433
FXUS61 KGYX 302254
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
654 PM EDT Tue Apr 30 2024

.SYNOPSIS...
An unsettled pattern continues tonight into Friday with waves of
low pressure bringing showers tonight and again Thursday. Cloudy
skies and onshore winds will favor high temperatures running
below normal through the rest of the week. High pressure builds
in from the north Friday for mostly fair weather into Saturday.
Chances for showers then increase Sunday into Monday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
650 PM Update...Little change to the going forecast. Showers
will move west to east across the forecast area this evening and
tonight. However, they will be light.

Previously...

A mid level ridge axis has remained over the forecast area for much
of today while a weak short wave and surface low approach from the
west. An elevated warm front with some Fgen forcing around 850 mb
has provided a focus for showers and elevated convection across
southern NH into SW Maine with Hi Res guidance struggling with the
timing and placement of these showers. Elevated instability is
forecast to dissipate this evening while the mid level ridge
axis breaks down. As this happens shower activity with embedded
thunder is expected to wane late this afternoon.

The weak short wave to our west and surface low has lead to
showers and convection blossoming over northern PA and central
NY. This activity is progged to spread into western New
Hampshire around 00Z and then overspreads the rest of the area
tonight. As this activity overspreads the area, instability
will have diminished with just widespread showers expected.
These showers will bring around a quarter inch of QPF before
ending around day break Wednesday. Plenty of low level moisture
and light winds may allow for patchy fog to develop tonight.
Lows will range from the upper 30s north to low 40s south.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
The mid level flow pattern will turn briefly zonal Wednesday with a
weak surface high crossing the area. This will bring mostly dry
conditions while skies remain mostly cloudy with light onshore
winds. This will maintain cool conditions across the area with
highs in the 50s.

A short wave will approach late Wednesday night bringing chances
for showers by day break Thursday morning. Before these showers
arrive there is potential for patchy fog across the area. Lows
Wednesday night will generally be in the low to mid 40s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
A convectively induce short wave will roll across a 500 mb ridge
bringing the next chance for widespread showers Thursday. This
system exits by Friday morning with high pressure building in
from the north. Heights build to the west of New England Friday
into Friday night while an upper low develops southeast of
Atlantic Canada. The ridge axis will gradually slide east into
the weekend favoring a warming trend, while the upper low
offshore brings the threat of marine air moving into the region
keeping high temperatures cooler than normal. Ensembles favor
dry conditions Friday into Saturday followed by a warming trend
early next week. This warming trend will also coincide with
increasing moisture bringing chances for showers late in the
forecast period.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Ceilings across the area vary from around 1000 feet
to 4000 feet with expectations for ceilings to lower tonight.
Showers will also overspread the area west to east starting
around 00Z. Lowering cigs and reduce vsby in SHRA and fog will
bring periods of IFR to LIFR across most TAF sites for several
hours tonight. Ceilings will lift Wednesday morning with
conditions improving to MVFR and then VFR Wednesday afternoon.
Another round of MVFR to IFR is likely Wednesday night in
lowering cigs.


Long Term...Low cigs and showers will likely bring periods of
MVFR Thursday. Conditions improve to VFR for Friday into
Saturday. Increasing chances for showers Sunday brings the next
potential for flight restrictions.

&&

.MARINE...
Short Term...Winds and seas will remain below SCA thresholds
tonight through Wednesday night. Weak low pressure crossing the
waters will bring chances for showers tonight.

Long Term...Winds and seas remain below SCA thresholds Thursday
into the weekend. Low pressure crossing the waters Thursday
will rounds of showers followed by high pressure building in
from the north Friday into the weekend.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...Ekster/Schroeter
SHORT TERM...Schroeter
LONG TERM...Cannon
AVIATION...
MARINE...