838
FXUS61 KGYX 131529 AAB
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1129 AM EDT Mon May 13 2024

.SYNOPSIS...
High pressure builds in and moves offshore today. A warm front
stalls through central New England on Tuesday, then a slow
moving cold front stalls on Wednesday. Low pressure passing
south of New England spreads moisture and showers in from late
Tuesday into Thursday. Conditions dry out late in the week as
New England sees a period between systems, and then likely turns
unsettled again by late next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1130 AM Update: Going forecast remains in good shape with minor
adjustments to late morning temperatures/dewpoint and cloud
cover. Expect conditions to remain dry through early evening
with shower chances increasing after that.

910 AM Update: Made some adjustments to boost morning
temperatures and dewpoints based on recent observations and
delayed the increase in cloud cover slightly based on morning
GOES 16 visible satellite imagery with mostly clear skies across
the area this morning. No changes for the forecast through this
afternoon with gradually increasing cloudiness and a chance for
a shower across NH towards evening as warm advection strengthens
across the area.

630 AM Update...Just the usual minor edits to T/Td with this update
to match up with observations. Otherwise, the forecast is on track.

Previous...

Patchy fog may develop in areas where clouds clear out early
this morning, but what does develop should quickly dissipate by
7 to 8 am. Otherwise, southerly flow returns today as a broad
area of high pressure moves into the western Atlantic, centered
just to the east of the Carolinas. Aloft, a 500mb ridge moves
overhead, although just briefly, which will keep most of the
area dry. We should start off with more sun today, but
sufficient moisture around 850 mb and some low-level instability
will bring partly sunny to mostly cloudy skies from late
morning into the afternoon. Weak PVA aloft and an approaching
warm front may bring a few showers into New Hampshire and the
western Maine Mountains late in the afternoon or early evening,
but again most will be dry with temperatures reaching the mid
to upper 60s. Coastal areas will probably be a few degrees
cooler with the seabreeze coming in off the chilly Gulf of
Maine.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Showers will continue to overspread the region from west to east
through this evening and tonight as shortwave energy moves
overhead. Highest coverage of showers is expected across
central and northern areas with amounts ranging from 0.10" to
0.25" possible. Coverage of showers decreases with southward
extent with a few hundredths to 0.10". Mostly cloudy skies will
keep temperatures in the 40s to lower 50s.

Most of these showers will shift east of the area Tuesday
morning but may continue a little longer across northern and
eastern areas near the warm front that looks to stall across
western ME. Warm S/SW flow and more sunshine to the south and
west of this boundary is expected to send temperatures well into
the 70s across NH and SW Maine with 80 not out of the question
in southern NH. Farther east, temperatures will be cooler with
mostly 60s expected due to more cloud cover and more of a fetch
of the Gulf of Maine.

A cold front will approach the area in the afternoon from the west,
aiding in additional shower development in the afternoon,
especially northern and western areas. The previously mentioned
warm temperatures and decent lapse rates aloft will result in a
few hundred J/kg of MUCAPE per the 00Z HREF mean across NH and
into the western ME mountains to support a few thunderstorms
with perhaps small hail in addition to heavy downpours and
lighting. CAMs are in pretty good agreement with bringing this
convection farther to the south and east into early Tuesday
evening.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Overview...

A cut off low gradually moves through the Ohio River Valley and
south of New England Wednesday and Thursday. A short wave ridge
passes through on Saturday, and then another system approaches
New England by next Sunday.

Details...

A cold front sags southward late Tuesday night through
Wednesday, with showers expanding along this front as a slow
moving low tracks south of the area and sends moisture
northward. Showers remain likely Tuesday evening into Tuesday
night, and gradually increase as the front moves southward into
coastal areas by Wednesday. The bulk of the moisture stays south
of the region, but the slowing front serves to focus shower
activity on Wednesday, and possibly into Thursday as well. The
front stalls, likely through the middle of the forecast area
from east to west. There will be wet periods during this
timeframe into Thursday, but coverage looks to gradually lessen
as the forcing weakens. Some showers still can`t be ruled out on
Friday as the low tracks out to sea.

A quick shortwave ridge likely passes through on Saturday, but
the next system will be quick on it`s heals with moisture
spreading in from the southwest. It`s still unclear whether this
ridge will pass through during the day on Saturday, or if it
moves through a bit more quickly and allows showers to move in
by the afternoon hours. We`ll need to wait a little longer to
iron out these details, but that looks like the set up at this
point.

&&

.AVIATION /16Z MONDAY THROUGH FRIDAY/...
Short Term...Patchy fog may develop in areas through 12Z this
morning where clouds manage to clear out. Otherwise, VFR
conditions today, but approaching low pressure will bring a
round rain showers to the region from early this evening into
Tuesday morning. MVFR to IFR cigs and MVFR vsbys are possible
with this activity before a break and return to VFR conditions.
Outside of showers, patchy fog is possible as well. Additional
showers along with thunderstorms are then expected to develop
Tuesday afternoon. Highest potential for impacts with these look
to be generally along and north of a LEB-AUG line with IFR
cigs/vsby possible. Marine fog may also impact PWM and RKD late
Tuesday afternoon.

Long Term...Ceilings lower at all terminals with showers
Tuesday night, with MVFR conditions likely and periods of IFR
possible. These conditions continue on Wednesday, and then
gradually improve into the day on Thursday. VFR likely doesn`t
return fully until Friday.

&&

.MARINE...
Short Term...Broad high pressure moves into the western Atlantic
today, centered just offshore of the Carolinas. This will bring a
gradually increasing southerly flow through Tuesday, possibly
bringing SCA conditions over the outer waters by late in the day
Tuesday with wind gusts nearing 25 kt as low pressure and cold
front approach the region. Shower chances will increase across
the waters tonight into Tuesday.

Long Term...The cold front continues to slowly approach the
waters Tuesday night, and stalls near the coast or just inland
from the coast by Wednesday. A slow moving low pressure system
passes south of the waters Wednesday and Thursday. These two
features bring freshening southerly flow, becoming easterly by
Wednesday and Thursday, with SCA conditions possible during this
time frame. This system slowly moves eastward on Friday, with
waves likely lingering near 5ft on Friday.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...Arnott
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...