Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/07/18
Area Forecast Discussion
National Weather Service Boston/Norton MA
959 PM EST Tue Nov 6 2018
.SYNOPSIS...
Widespread rain with embedded heavier showers and thunderstorms
pushing offshore around midnight. Drier, cooler conditions will
move in on Wednesday with gusty west winds, and will continue
into Thursday night as high pressure passes south of the region.
Low pressure approaches Friday afternoon, bringing a round of
rainfall through Friday night. The low exits early Saturday, with
dry and cool conditions returning next weekend. Another low may
work up the east coast with more precipitation early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
10 pm update...
Clearing out, drying out. Last of the rain pushing offshore around
midnight, some gusty SW winds lingering. If cold air advection
as noted below to the W can slip in, can`t rule out gusty winds
to continue overnight, mainly W as low level wind profiles remain
stout beneath the broader H5 trof regime. Best chance N/W MA and
CT, especially over the high terrain of Berkshires and Worcester
Hills as the latest RAP model notes.
Acknowledge presence of low clouds and fog W within light winds
resultant of antecedent rains, where dewpoints remain high around
the lower Hudson River Valley of NY trickling into W New England.
0z Albany sounding exhibits as to why, a dry inversion capping
low level moisture at the surface. However, upstream, blustery W
winds and lower dewpoints evident over W upstate NY and Central
and W PA. 0z Buffalo, Cincinnati, Pittsburgh soundings exhibiting
steepening lapse rate profiles and boundary layer drying. Some
stratocumulus developing at the top of the mixed layer. If the
latest RAP is correct, we`ll be contending with low cloud and/or
fog issues through roughly around midnight, but then dry air
advection should win out clearing things out towards morning,
breezy W winds in concert. Dewpoints and temperatures dropping,
lows getting down into the 40s for most locations.
Do acknowledge the second line of showers along a secondary frontal
wave, more appropriate to define as a dewpoint discontinuity. May
see some of this shower activity clip the Berkshires, losing its
punch as associated mid-level dynamics slip NE and SW dry-slot
pushes in. Chance PoPs.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Cold advection aloft Wednesday, but the flow is from the west-
southwest so much of this cold air remains just to our north.
The GFS and ECMWF show -20C air along the NH border Wednesday
Models show a fair amount of cloud-level moisture in Northern
New England and with the nearby moisture we could see some
diurnal clouds during the afternoon. But figure a mostly sunny
day especially south of the Mass Pike.
With the available sunshine, temps in the mixed layer will
support max temps in the mid 50s to lower 60s. Winds in the
mixed layer will support gusts of 20-25 mph.
Winds diminish Wednesday night while dew points fall to the
low to mid 30s. That suggests min temps reaching the 30s inland
and lower 40s along the coast.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Highlights...
* Dry and brisk Thursday
* Rain chances return by midday Friday through Friday night
* Dry conditions and cool this weekend into early Monday
* Low pressure may work up the east coast with more rain
Monday night and Tuesday
Overview and model preferences...
An active, progressive mid level steering pattern in place
across the lower 48 on Thursday. Noting a digging H5 long wave
trough across the central U.S. on Friday which swings NE to the
Great Lakes and interior northeast early Saturday as an H5 cold
pool moves into the Great Lakes and Ontario into Quebec. As the
trough lifts by 12Z Sunday, will see a return to a dry but cool
conditions into Monday. Yet another system digs, though much
further S into the Plains/central Mississippi valley early next
week. This will bring another shot of moisture as low pressure
works up the east coast, which could bring some heavier rainfall
and gusty winds Mon night into Tuesday.
12Z models in rather good agreement through the weekend, then
noting some model solution divergence mainly with the timing of
the system working out of the Gulf of Mexico, with fair
agreement between the 12Z GFS and GGEM, with the low a bit
further offshore on the ECMWF. Used a blend of available
guidance for this portion of the forecast.
Temperatures...
Overall, temperatures will run close to or slightly below
seasonal levels from Thursday through most of the weekend. May
see temps tumble, down to around 10 degrees below normal on
Sunday. Readings will rebound a bit early next week, though
continue to running around 5 degrees below normal. While
overnight lows will be mild Fri night, they fall to near or
below freezing both Sunday and Monday nights.
Precipitation...
With a slug of moisture working NE across the region late
Fri/Fri night, may see anywhere from 0.5 to 1 inch of QPF
across most areas but will taper off quickly Saturday morning.
May see the precip end as some snow across the E slopes of the
Berkshires as well.
With the cooler temperatures in place with the late Monday into
Tuesday system, could see light snow accumulations across N
central and W Mass, possibly into N central CT Mon
night/Tuesday. However, this is quite a ways out, with a lot of
changes that could work in, but is something to monitor.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Wednesday Night/...Moderate confidence.
Rest of tonight...
MVFR-LIFR lingering over SE New England terminals with RA, some
embedded +RA, lower risk TSRA. SW gusts up around 25 kts. Last
of RA pushing offshore around 5-6z. Behind, SCT-BKN MVFR-IFR
CIGs with light winds, holes in between the cloud decks promote
BR/FG. Thinking only a brief period, as the overnight period
progresses, flow more W, becoming breezy, CIGs and VSBYs lift,
becoming VFR.
Wednesday into Wednesday night...
SCT-BKN CIGs around 4 kft. VFR. W winds, gusty at times around
20 to 25 kts, diminishing overnight.
KBOS Terminal...
Hold VFR but can`t rule out some SCT MVFR sneaking in overnight,
clearing out towards morning as W winds become brisk, gusts up
around 25 kts that continue into Wednesday.
KBDL Terminal...
SCT-BKN MVFR-IFR this evening, should erode overnight around
midnight into the morning hours as W winds become brisk.
Outlook /Friday through Sunday/...
Friday: Mainly VFR, with areas MVFR possible. Breezy. RA
likely.
Friday Night: Mainly MVFR, with local IFR possible. Windy with
local gusts to 30 kt. RA likely.
Saturday: Mainly VFR, with local MVFR possible. Windy with
areas gusts to 30 kt.
Saturday Night: VFR. Windy with local gusts to 30 kt.
Veterans Day: Breezy.
Sunday Night:
Monday: Slight chance SHRA, slight chance SHSN.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Wednesday Night/...Moderate confidence.
S-SW wind gusts have diminished below Gale Warning criteria this
evening as the low level jet has pushed away. Have converted the
Gales to Small Craft Advisories for most of the waters through
Wednesday. Winds have diminished below Small Craft on both
Boston Harbor and Narragansett Bay, so ended the headlines there
for now.
Expect the cold front to move past the waters by around midnight.
Expect showers, possibly a couple of thunderstorms until the
front moves past. Areas of fog with low vsbys.
Conditions improve overnight after the front moves through.
Partial clearing overnight.
Wednesday should feature west-southwest winds and gusts to
around 25 knots. Small Crafts may continue to be needed.
Seas will remain at 5 feet or higher on the outer waters and
RI/Block Island Sounds much of the period.
Outlook /Thursday through Sunday/...
Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas locally approaching 5 ft. Chance of rain.
Friday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 12 ft. Rain.
Saturday: Low risk for gale force winds with gusts up to 35 kt.
Rough seas up to 10 ft. Slight chance of rain.
Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas.
Veterans Day: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas.
Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Monday: Winds less than 25 kt. Slight chance of rain showers.
&&
.HYDROLOGY...
Flood Warnings continue on the CT River at Middle Haddam. Water
levels are coming down, however we are monitoring some slight
rises at times resultant of tidal influences downstream plus
rains that fell earlier today. The warming goes through Wednesday
evening.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 6 PM EST Wednesday for ANZ231>235-
237-250-254>256.
Small Craft Advisory until 1 PM EST Wednesday for ANZ251.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB/Sipprell/EVT
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...WTB/Sipprell/EVT
MARINE...WTB/Sipprell/EVT
HYDROLOGY...WFO BOX Staff
Area Forecast Discussion
National Weather Service Burlington VT
934 PM EST Tue Nov 6 2018
.SYNOPSIS...
A mild and breezy night anticipated as steadier rainfall becomes
scattered showers. Lows will be in the 40s with southwest winds 15
to 25 mph with localized gusts up to 40 mph possible, especially
Saint Lawrence Valley. Temperatures will warm into the 50s on
Wednesday with breezy southwest winds prevailing. Temperatures will
slowly trend to below normal levels by the end of this week with
mainly scattered mountains snow showers.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 932 PM EST Tuesday...Only a small area of showers remains
across the area, what`s left of the line that we were watching
earlier, and is stracking across Rutland and Windsor counties.
Winds will continue to be gusty overnight. Previous discussion
follows.
Water vapor shows potent short wave energy lifting across
western NY/PA this aftn with ribbon of enhanced mid level
moisture shifting into central New England. The well defined dry
slot has resulted in some clearing skies across central/western
NY, which has created a narrow axis of sfc based cape values of
100 to 300 j/kg. This instability combined with potent short
wave dynamics has produced a weak line of convection this aftn
with some lightning. Based on HRRR/NAM 3km and RAP this should
angle toward the southern SLV/western dacks with additional
showers and slight chc of thunder. Given developing 925mb to
850mb jet of 35 to 50 knots, the potential for localized gusty
southwest winds will need to be watch closely in the stronger
convective elements.
Large scale pattern shows developing mid/upper level trof with
cooling 850 to 700mb thermal profiles on brisk southwest/west winds.
Soundings show better mixing overnight as cooling aloft occurs and
this combined with aligned southwest to northeast flow in the SLV
will promote localized gusts btwn 35 to 40 knots overnight. Wind
speeds should remain below advisory levels, but given recent
rainfall and saturated soil a few minor power outages are possible
from downed small trees/limbs. Strongest core of winds will occur in
the immediate valley from near KOGS to KMSS with 30 to 35 knots
dacks and 25 to 30 knots cpv. Progged 850mb temps start btwn 6-8c
this evening, but cool to near 0c by 12z Weds, resulting in summit
temps near freezing. However, given mixing and clouds anticipate
lows in the wider valleys mainly in the mid 40s. Any additional
rainfall will be light and mainly confined to the southwest upslope
regions of the dacks/northern Green mountains.
On Weds into Weds night our attention turns for synoptic to
mesoscale features associated with lake effect showers. The
combination of cooling 925mb to 850mb thermal profiles will develop
enough low level instability with lake-air temp dif, while favorable
aligned flow wsw to ene will produce some multi-cellular lake precip
over the dacks/southern slv. The limiting factor will be the 850mb
temps only -1c to -3c and soundings show large dry layer overhead.
Better moisture and upper level dynamics arrive ahead of weak
secondary front around 00z Thursday, which may help to enhance
precip before band shifts south of fa by Thursday as colder profiles
develop on northwest winds. Sounding show good mixing to near 850mb
on Weds, progged temps btwn -1c and 1c, should support highs well
into the 50s. However, a large elevation spread in temps will be
anticipated with summits holding in the 30s. Weds night temps cool
back into the low/mid 30s nek/dacks to near 40f cpv. Mixing of bl
will once again keep temps from completely falling off, even as
850mb temps cool another couple of degrees by 12z Thurs.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 328 PM EST Tuesday...As a departing low pressure system
pulls towards Newfoundland, the upper and mid level flow will
turn more zonal across the North Country developing some lake
effect rain/snow Thursday morning off of Ontario. The flow looks
fairly uniform and should push right over the Tug and just
south of Saint Lawrence county. With modest cold air advection
expect temps to be in the low to mid 40s for high temps. The
lake effect weakens overnight as the lake induced CAPE falls off
due to temps only in the mid 30s overnight. Weak ridging builds
in during the overnight hours before clouds start to push in
ahead of our next system.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 328 PM EST Tuesday...The weekend looks quite active as an
upper level trough digs in over the eastern conus. The
deterministic runs have been fairly consistent in developing a
double barrel low pressure type solution with a low that tracks
up the Saint Lawrence and one that tracks up the Atlantic coastline
Friday into Saturday. That scenario puts the North Country right
the middle of a high convergence zone which should lead to widespread
precipitation Friday night into Saturday. P-type will be interesting
because there will be some warm air pushing in aloft but with
wet bulb effects I would anticipate much of the North Country
even to the valley floors will see snow initially. As we move
into the day on Friday expect the warm air aloft to bring snow
levels up and so rain will become the dominant p-type below 2500
feet. By mid afternoon Saturday the lows will have pushed well
to the northeast and the flow become more orographic. Precip
will become more terrain forced and showery through the
afternoon.
High pressure moves in end the weekend as quiet weather returns.
Sunday will be on the chilly side with temps barely getting
above freezing for most of the region. Cold air advection with
mostly cloudy skies will make it difficult to warm much during
the day on Sunday. Coming out of the weekend we should see a
nice day on Monday before another full CONUS trough brings
a mid latitude cyclone through the region.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...VFR at all sites currently. May have some
brief periods of MVFR in heavier rain showers as decaying line
of showers continues to move across the region. SLK briefly went
down to 2sm in +ra. Gusty southwest winds at 15 to 25 knots
with localized gusts 35 to 40 knots at mss/slk develops by 00z.
This increase in sfc mixing should allow cigs to lift into
mvfr/vfr categories with rainfall quickly decreasing in areal
coverage. These conditions will prevail overnight with some
lowering of cigs at slk as lake moisture is advected into the
dacks. Some periods of ifr cigs are possible toward 09z Weds,
while downslope flow off dacks results in vfr conditions at
btv/mpv.
Outlook...
Wednesday Night: VFR. Slight chance SHRA.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Likely RA, Likely SN.
Friday Night: Mainly VFR, with areas MVFR possible. Definite RA.
Saturday: Mainly VFR, with areas MVFR possible. Chance RA, Chance
SHRA, Chance SHSN.
Saturday Night: VFR. Slight chance SHSN.
Veterans Day: Mainly VFR, with local MVFR possible. NO SIG WX.
&&
.MARINE...
Lake wind advisory in effect tonight for southwest winds 20 to
30 knots, becoming 15 to 25 toward Weds morning. These winds are
likely to persist for Weds with seas 1 to 3 feet, except
localized waves near 4 feet in the open waters.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Neiles/Taber
SHORT TERM...Deal
LONG TERM...Deal
AVIATION...Neiles/Taber
MARINE...
Area Forecast Discussion
National Weather Service Grand Rapids MI
649 PM EST Tue Nov 6 2018
LATEST UPDATE...
Update/Aviation
.SYNOPSIS...
Issued at 300 PM EST Tue Nov 6 2018
It will be breezy and turn colder tonight with lingering rain
showers into the evening that will gradually taper off overnight.
A progressively colder airmass will continue to move in late this
week through the week into early next week. In fact high
temperatures Friday through the weekend into early next week will
only reach the 30s with occasional snow showers as even colder
air moves in.
&&
.UPDATE...
Issued at 650 PM EST Tue Nov 6 2018
The rain showers over the area have not been all that quick to
diminish. I increased the pop over the western sections to near
100% (since it is raining) for this evening.
The latest RAP model shows the deep moisture not pulling out until
after 9 pm, so that is when I allowed the pop to decrease to
chance over most of our western CWA.
Otherwise the on going forecast looks good (temperature and wind).
&&
.DISCUSSION...(This evening through next Tuesday)
Issued at 300 PM EST Tue Nov 6 2018
At 18Z KGRR radar trends show showers continue in progress across
much of our fcst area. Those will continue through late afternoon
before tapering off this evening. However some drizzle and lighter
rain showers will then linger overnight.
Peak wind gusts of around 30 to 40 mph have been reported across
our southern fcst area with gusts mainly in the 25 to 30 mph range
up north. A consensus of latest high res model guidance such as
the latest HRRR and namnst suggest that gusts in this range will
continue through around 21Z late this aftn.
Westerly flow lake effect mixed light rain and flurries will
develop during the early morning hours Wednesday as h8 temps fall
to around -6 to -8 C by 12Z Wed yielding delta t/s into the lower
teens with ample low level moisture in place. However a lack of
deeper moisture through the dgz is noted in model fcst soundings.
So we expect scattered light rain showers/patchy drizzle and
scattered flurries tomorrow into tomorrow night.
A sfc high pressure ridge will build in Thursday and bring
briefly tranquil weather.
A sharp upper level trough will approach from the northwest
Thursday night and cause increasing clouds and moisture. Pcpn will
develop during the early morning hours Friday and then likely
continue through most of the day as the upper trough axis moves
overhead. Thermal profiles by then look sufficiently cold for
snow as p-type. Some light snow accumulations on the order of an
inch or two seem possible especially on grassy surfaces.
Several rounds of lake effect snow showers are then expected
late in the weekend into early next week as a deep upper level
trough becomes entrenched and amplifies over the Great Lakes
region. Due to progressively colder air/ground temps this weekend
into early next week some hazardous travel conditions due to lake
effect snow showers are likely to develop from late Sun- Tue.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 650 PM EST Tue Nov 6 2018
Due to the strong winds and lake enhanced clouds expect some
light to moderate turbulence and light to moderate in cloud icing.
The freezing level will fall below 3000 ft by 04z or so with cloud
bases mostly in the 2000 to 3000 ft range and cloud tops will
mostly be in the 6000 to 8000 ft agl level, you should expect
light to moderate icing in the clouds through Wednesday. The
turbulence will subside some tonight as the winds decease some.
However I expect gusty winds (15 to 25 knots) to continue through
the day on Wednesday.
MVFR cigs will prevail through Wednesday. The rain showers are
expected to diminish by 04z or so but during the day Wednesday
another disturbance may cause some light snow showers or mixed
rain and snow showers. I put VCSH in the TAF since the coverage
tomorrow will be in the 20 to 30% range unlike this evening where
it is near 100% near I-96.
&&
.MARINE...
Issued at 300 PM EST Tue Nov 6 2018
A gale warning remains in effect through 1 am late tonight for
gale force winds in the 35 to 40 kt range that will result in wave
heights of up to around 7 to 11 feet. Winds should subside a bit
to below gale force very late tonight at which point a transition
to a small craft advisory will be needed through Wednesday evening.
&&
.HYDROLOGY...
Issued at 1207 PM EST Tue Nov 6 2018
River levels are generally above normal for the time of the year
with rises ongoing on many rivers, but none are expected to rise to
flood stage. We will see some ponding of water in low-lying and poor
draining areas however, due to the recent and ongoing rainfall.
Lake-effect showers will occur from tonight into the weekend with
fairly light rain and snow amounts. We may see some snow
accumulations Friday and Saturday. This should have little impact on
area rivers, and temperatures will not yet be cold enough to worry
about rivers freezing or ice jam formation.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Gale Warning until 1 AM EST Wednesday for LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...Laurens
DISCUSSION...Laurens
AVIATION...WDM
HYDROLOGY...63
MARINE...Laurens
Area Forecast Discussion
National Weather Service Gray ME
1043 PM EST Tue Nov 6 2018
.SYNOPSIS...
Low pressure exits through eastern Canada tonight and Wednesday,
with high pressure building towards New England from the Great
Lakes on Thursday. Low pressure will form along the Mid Atlantic
coastline Friday, before heading up the coast, reaching the
coast of Maine Friday night. This system will exit to our east
over the weekend as cold high pressure follows. Yet another
coastal low will move northeast along the Eastern Seaboard early
next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
1020 pm Update: Areas of dense fog across the NH valleys and
expect it to work into areas of ME as clearing occurs and
residual low level moisture persists. Not enough ventialation
will occur until very late tonight to prevent fog development.
Made adjustments to forecast to include fog.
915 PM Update...
A few changes to the forecast to account for precipitation
ending over much of the region. The Mid Coast will see rain
ending within the hour. Low clouds and fog are still entrenched
over the area, but westerly winds should increase overnight
helping to scour some of the moisture out.
545 PM Update...
Much of the precipitation has moved offshore, but another
healthy round is currently moving through northern Maine and
central/southern NH and shifting southeast. The actual cold
front is well behind and delineated by a line of convection
moving through NY state from Whippleville to Griffiss AFB to
near Cortland NY and moving east- with a couple healthy looking
cells where highs were in the 60s today. This line will diminish
as it does so but will bring additional rain and perhaps a flake
or two to the higher elevations later tonight. Have adjusted
PoPs to drop off quickly after 9 PM outside of the mountains in
line with latest CAMs. Temperatures are on track for the evening
and will drop into the 40s with a few 30s showing up in the
higher elevations.
Previous discussion...
Bands of precipitation continue to move quickly northeast across
the region, with roughly half to 3/4 inch precipitation still
expected in most areas through this evening. This precipitation
will be triggered by a fast moving system and a surface
occlusion that will race through eastern Canada tonight. Any
leftover areas of steady rain this evening will tapper to
showers.
Latest HRRR indicates the showers will move off the coast
before midnight. Thereafter, a well aligned and strengthening
northwesterly flow will allow for upslope conditions to develop
in the higher terrain of the mountains. Blended timing of
transition from steady rain this evening to more of a showery
nature with our neighbors.
Overnight lows expected to be in the 40s in all areas, due to a
well mixed lower atmosphere.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Cold air advection continues over the northern high terrain on
Wednesday into Wednesday evening with scattered snow showers
over the higher terrain. It will remain below normal for this
time of the year with highs between 45 and 55 over the region
Wednesday and readings in the 30s Wednesday night.
Well aligned gradient in cold air advection pattern will allow
for increasing wind gusts throughout the day. A few gusts
between 30 and 35 knots possible.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
We remain in a familiar pattern with a trough over the central
to eastern United States with our area on the downstream side of
it. Thus we get all the waves exiting the trough, with another
round of precipitation every couple of days. A more potent wave
drops down the back side of the trough over the northern plains
on Thursday then rounds the bottom of the trough and pulls east
through the Great Lakes and southeast Canada this weekend. With
the relatively recent Arctic origin of this air mass, we can
expect some cold air to punch in behind the departing low as
well. This gives way to brief ridging in advance of the next
trough digging through the center of the country next week.
Broad high pressure will slide east across the Great Lakes
Thursday and Friday with a cool northwest flow over New England
on Thursday. The center of the high drifts across into our area
by Friday morning, so we should see temperatures bottoming out
below freezing.
The next storm system arrives on Friday with the energy split
into two parts. The initial wave moves into Canada while a
secondary low spins up over the Mid Atlantic and southern New
England coastline. This will keep us on the cold side of this
system, so we will have to pay attention to precipitation type.
The temperature profile of the atmosphere looks to favor a rain
or snow type of situation depending on the near-surface
temperature as opposed to a freezing rain or sleet type of
situation. The timing of this storm arriving late in the day
Friday favors more in the way of rain as the sun has had all day
to warm the ground layer even through increasingly thick
clouds. However, dry air on the front end could favor
evaporational cooling and a snowy start. At this point, most
likely areas for snow will be mainly in the mountains and
foothills, with coastal and southern areas staying rain. There
could be significant accumulation of snow in the north where it
may never transition to rain. Still a bit of uncertainty on how
much moisture gets wrung out with this one, though the GFS and
ECMWF have both come in fairly wet. If our rivers haven`t had
time to recede some more by then we will have to also be alert
for renewed flooding.
Precipitation should move out Saturday morning with high
pressure building in for the weekend. It will be colder as the
air behind this storm has origins in the Arctic. Currently
looking at highs in the 30s to low 40s on Sunday and Monday.
Saturday night won`t be as cold due to the pressure gradient
behind the departing system keeping the nighttime atmosphere
fairly well mixed. However, the bottom may fall out Sunday
night when high pressure moves through. Low level dewpoints in
the single digits suggest we have a good ways that we could
fall. For now have indicated widespread teens for lows, but it
could be a little colder if it stays clear and calm all night.
Next wave comes into our area on Tuesday. With a track a bit
further south and east than previous storms, there is a chance
it could have more snow with it.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
Short Term...1020 pm Update to reflect dense fog across some of
the TAF sites in NH attm and will likely develop into ME over
the next few hrs. An AWW has been issued for dense fog until
3am.
Previous Discussion:
IFR and LIFR conditions will continue into early
this evening. LLWS expected as well early. Conditions improve
tonight and will continue through Wednesday and Wednesday night
with VFR conditions outside the mountains.
Long Term...Should see VFR conditions for most areas Thursday,
though MVFR could linger in westerly upslope areas into Thursday
evening. Expect increasing clouds and lowering ceilings on
Friday with precipitation beginning late in the day. Southern
and coastal areas likely to see rain, while northern areas get
some snow. Should see at least IFR conditions lasting into
Saturday morning before a westerly flow brings clearing to the
coastal plain while the mountains hang on to some MVFR ceilings
and snow showers.
&&
.MARINE...
Short Term...SCAs will remain in effect through Wednesday.
Long Term...Westerly winds are likely to stay strong into
Thursday before diminishing with the arrival of high pressure.
Coastal low pressure tracks near Cape Cod Friday evening, with
an easterly flow over the Gulf of Maine likely increasing back
into the Small Craft Advisory range again. Once this low passes
by, a westerly flow moves in behind a front and could reach gale
strength.
&&
.HYDROLOGY...
Rivers in southern NH, particularly but not limited to the
Merrimack basin, are running at high levels for this time of
year. Given the potential for a half inch to 1 inch of rain with
locally higher amounts into this evening, we will have to
continue to monitor this area for potential minor flooding. A
river flood warning has been issued for North Chichester.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 6 AM to 5 PM EST Wednesday for
ANZ153.
Small Craft Advisory until 5 PM EST Wednesday for ANZ150>152-
154.
&&
$$
NEAR TERM...Marine