NWS Gray, Maine Area Forecast Discussion



000
FXUS61 KGYX 031328
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
928 AM EDT Fri Apr 3 2020

.SYNOPSIS...
A large, oceanic low positioned southeast of Cape cod will move
southward away from the area through tonight. This will bring
gradual improvement to the rainy, windy, raw conditions
currently observed. High pressure then builds in for the
weekend. For the most part, the weather pattern will be
conducive to dry weather through midweek.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

925 AM...at 13z a 976 millibar low was centered well southeast
of Cape Cod. Latest surface analysis shows the low continuing to
meander to our south and west with steadier precipitation
slowly tapering off from northeast to southwest. Last nights QPF
was rather heavy across central Maine and portions of the Maine
mountains/foothills with rivers responding accordingly. We`re
monitoring portions of the upper Kennebec River as well as the
swift at Roxbury for potential flooding. Otherwise...we`re still
evaluating the amount of coastal flooding, splash-over, and
erosion that occurred with the 7 AM high tide this morning. For
this ESTF update...minor adjustments to near term grids to
reflect the current mesonet as well as radar trends.


Prev Disc...
745 AM Update...
Only minor changes thus far... did tweak winds a bit according
to observed trends. Resulted in slightly higher gusts over land
and slightly lower gusts over the waters off the Mid Coast of
Maine. The oceanic low has risen by 4 mb in the last 4 hours
with RAP analysis showing the expect southern component of
movement as well. A broad area of rain currently envelopes
almost the entirety of New Hampshire with showers continuing
over Maine.

Previously...
Today continues the recent trend of rainy, windy, raw conditions
as a large, stacked storm over the open Atlantic churns east of
Cape Cod and south of Nova Scotia. As of 330 AM, RAP13 analysis
showed the low at 980 mb. A strong northeasterly low jet over
the Gulf of Maine, on the north side of the low will continue to
produce widespread wind gusts on the order 20-30 kts through
the day. Winds maximize along exposed coastal areas later this
morning...though falling just short of advisory- level winds, do
still expect wind gusts along the coast to top out 35-40 kts
with strongest gusts over the east- facing New Hampshire
Seacoast.

Early this morning, a broad area of moderate rainfall associated
with a wave rotating around the low blanketed most of the
area...this will continue to rotate westward into New Hampshire,
focusing in the Whites. Behind this wave dry advection from the
north and weaker forcing will allow steady rain to turn more
showery, gradually losing coverage and intensity from north to
south. By the end of the day showers will be relegated to
southern NH and extreme southwest ME.

Quite dry air quickly filters in aloft today, clearing out most
upper level clouds, however low stratus cloud cover will hold
temperatures in the 40s today. The exception is over the
Connecticut River Valley where some afternoon clearing may
allow temperatures to reach up around 50 degrees.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Conditions will continue to gradually improve tonight with
drier air filtering in from the north, behind the departing and
weakening oceanic low. Breezy conditions will continue, except
for in sheltered valleys where an abundance of lingering low
level moisture may allow fog to develop. High pressure builds in
from the northwest on Saturday, helping to break up some of the
clouds, and allowing afternoon temperatures to warm an extra
couple degrees, into the upper-40s to near 50 over most of the
area.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
High pressure remains over the region Saturday night. A weak
cold front crosses the region Sunday into Sunday night bringing
low chances for showers, mainly in the mountains. High pressure
builds in for Monday and Tuesday. Thereafter, large divergence
in model solutions for mid to late week with low confidence in
the forecast. Will keep PoPs conservative midweek, and then
gradually ramp up late week. Low confidence.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
Short Term /Through Saturday/...Widespread MVFR with areas of
IFR in -RA persists this morning accompanying northeast winds of
15-20 kts, gusting to around 30 kts. A low level jet just off
shore peaks later this morning with gusts up to 35-40 kts
possible along the coast, especially at PSM. Winds at HIE and
LEB remain below 20 kts in their more sheltered locations.
Although rain will gradually come to end today, from north to
south, MVFR ceilings will linger at most sites through tonight
under decreasing NE flow. High pressure building tomorrow will
allow ceilings to lift and scatter with a return to VFR
expected.

Long Term...Mainly VFR conditions expected Saturday night
through early in the week as the region remains in an area of
high pressure. Pockets of MVFR possible Sunday in association
with weak cold front.

&&

.MARINE...
Short Term /Through Saturday/...A large oceanic low will
finally pull away to the SSE through tonight with a long, slow
downward trend in seas and swells following its peak around mid-
day today. Gale Warnings are posted for all zones accept for
Casco bay where strong SCA conditions are expected...conditions
will back down below Gales tonight. Regarding seas, wave action
peaks later this morning with near-shore waves 5-12 ft to as
high as 18 ft over the waters. Due to the size and residence of
the ocean storm, seas will be slow to come down with SCAs
lingering into tomorrow at Penobscot Bay, into early Sunday at
Casco Bay, and perhaps into Sunday night over the waters.

Long Term...Hazardous seas will gradually diminish by Sunday
night, with sub-sca conditions expected for early next week.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides will trend up until reaching their monthly
peak next week. Meanwhile, a powerful storm off of Cape Cod will
finally pull south and away out to sea through tonight. The long
residence of the storm over the Atlantic along with a brief
retrograde early this morning/last night has lead to strong seas
and storm surge focused along southern coastal areas where
easterly fetch is maximized and east-facing shoreline is most
vulnerable.

At 08Z this morning, analysis from the Portland tide gauge
reflected about 2.4 ft of storm surge. Based on observed
trends, expect surge to peak around 09-10Z this morning at
2.5-2.7 ft at Portland and points south (higher surge south).
When combined with a peak tide at 11Z and near- shore waves up
to 12 ft, expect coastal flooding and erosion along the New
Hampshire seacoast this morning. The threat generally decreases
heading north into Maine where northeasterly winds are less
conducive to wave action, but even along the Mid Coast some
splash-over issues are possible due to surge and ESErly swells.
In addition to the Coastal Flood Warning in place for coastal
Rockingham Co NH and advisories for coastal Cumberland and York
Co ME, coastal flood statements have been posted for the
MidCoast where some splashover and erosion is possible.

&&

.EQUIPMENT...
The last GYX upper air observation was March 25 at 12Z.
Unfortunately, a disruption in gas supply has temporarily halted
observations from GYX. It`s unknown when supplies will be restored
and upper air observations resumed.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ153.
     Gale Warning until 6 AM EDT Saturday for ANZ150-152-154.
     Gale Warning until 8 PM EDT this evening for ANZ151.

&&

$$

ES

NWS GYX Office Area Forecast Discussion