Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/19/18
and the previous forecast discussion is below. STP
&&
.SHORT TERM...valid for Thu and Fri...
Instability and low to mid-level moisture have resulted in a
cumulus field over SE MT and altocu over the central zones. Radar
was quiet so far this afternoon and latest HRRR still showed
possible isolated showers over SE MT, but they were toned down
from previous runs. Nonetheless, will keep isolated showers over
the SE through 03Z, as the lingering vorticity from the system to
the E departs the area. On Thursday, weak jet divergence will push
N into the region as an upper low pushes E toward the four-
corners region. Other than the upper-level lift, some difluence
will move into the SW mountains, bringing a slight chance of
afternoon showers. As the low continues moving E Thursday night,
moisture will increase ahead of the low over the forecast area. A
slight chance for mountain showers will translate E overnight into
SE MT/Sheridan County WY. Temperatures in the low to mid 30s will
support snow mixing with the rain showers. Vorticity spokes N of
the low will provide some lift to the area on Friday, while jet
divergence affects the SE zones. Chances for mainly rain showers
will continue over the SE part of the area and will decrease from
N to S during the day. The system and it`s forcing will continue
moving E Fri. night and chances for showers will decrease over the
SE. Temperatures each day will average in the 50s. Arthur
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
No significant changes in the extended forecast period.
Saturday continues to look dry,with ridging work in. Saturday
appears to be the warmest day with highs up into the 60s. Sunday
still has a weak cold front moving through the region. so far this
really does not amount to much more than a bit of a cool off, as
best energy stays north.
Another lobe of energy rotates into the
region Sunday evening/night depending on your preferred model.
Timing varies by about 12hrs between the GFS and ECMWF, with ECMWF
running slower. That said, the track and progged period of
heavier precip does appear pretty consistent, bringing best
accumulations along southern tier of the CWA with lesser amounts
further north. Have continued with some chance PoPs from Sunday
evening into Tuesday morning to address potential of both models.
Coolest day at this point appears to be Monday as precip is
crossing the region.
Ridging returns following this system, beginning either Monday
night or Tuesday afternoon. This points to another round of
seasonally warm, and generally dry conditions to end the forecast
period. AAG
&&
.AVIATION...
Expect VFR conditions to prevail through tonight. An isolated
shower with brief MVFR conditions is possible near KBHK through this
evening. LLWS is possible near KSHR after 12z Thursday. RMS
&&
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
-----------------------------------------------------------
BIL 034/058 036/057 035/069 036/063 035/057 033/066 034/068
01/B 11/B 10/U 11/B 34/W 32/W 11/B
LVM 030/055 032/060 033/073 035/066 033/056 030/065 032/070
01/E 21/U 01/U 22/W 34/W 32/W 21/B
HDN 032/059 035/057 034/067 034/063 034/057 032/066 031/069
00/B 22/W 10/U 11/B 44/W 32/W 11/B
MLS 033/058 036/058 034/066 035/061 035/057 033/063 032/068
21/B 22/W 10/U 11/B 23/W 21/U 11/U
4BQ 031/056 036/054 034/065 035/061 036/054 032/061 030/065
10/B 22/W 20/U 11/B 44/W 31/B 11/B
BHK 029/052 034/050 034/062 037/059 034/057 031/058 031/062
21/B 22/W 10/B 11/B 24/W 21/U 11/U
SHR 029/060 034/055 032/071 034/069 035/054 031/065 030/068
00/B 23/W 20/U 11/B 34/W 42/W 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Louisville KY
914 PM EDT Wed Apr 18 2018
...Forecast Update...
.Forecast Update...
Issued at 910 PM EDT Wed Apr 18 2018
As of 9 pm EDT, radar shows the line of showers from near Lexington
southwest to Hodgenville, moving quickly east. Highest gusts
reported across the area with its passage has been 48 mph at SDF
with several 40-45 mph gusts across southern IN and north central
KY. Timing the line puts it through the rest of the forecast area
between 10-11 pm EDT. A few rumbles of thunder remain possible in
addition to the gusty winds.
In its wake, expect a sharp temperature drop along with gusts 30-40
mph through the rest of the evening and into the first part of the
overnight. Upstream gusts across southwest IN and southern IL have
been 35-45 mph. As a result, no changes made to the Wind Advisory at
this time.
After some clearing, clouds will fill back in overnight with a low
stratus deck that will likely persist through Thursday morning
across southern IN and north central KY. Lows tonight will be in the
upper 30s to around 40 degrees.
Issued at 630 PM EDT Wed Apr 18 2018
Line of low-topped showers has developed across southern Indiana and
and extreme north central Kentucky. It formed in an area of higher
dewpoints where the recent SPC mesoanalysis shows a bubble of 500
J/kg SB CAPE. It`s racing across the area in a higher shear
environment so the main concern is gusty winds mixing down over the
next few hours. So far however wind gusts have remained at or below
40 mph. Recent HRRR and other hi-res models handling this line
fairly well. Adjusted hourly PoPs to match reality and to
extrapolate the line through the evening hours. Minor other
adjustments were made.
&&
.Short Term...(This evening through Thursday night)
Issued at 315 PM EDT Wed Apr 18 2018
...Strong Winds and Gusty Showers Through This Evening...
Strong and fast-moving sfc low has filled in a little bit, now
1004mb over west-central Indiana. Main challenge through about
midnight tonight will be precip chances and wind potential. Very
high-momentum air is available aloft as the closed upper low makes
its way across Iowa and into northern Illinois. Starting to see wind
gusts around 30 mph already, and these winds will continue to ramp
up as the low passes to our north and its trailing cold front drops
in.
Deep moisture has so far been unavailable to generate precip, but
dewpoints over Kentucky have risen solidly into the 50s. Expect to
have some shallow scattered showers develop later this afternoon
through about mid-evening as the front pushes in. QPF is very light
and convection will be too shallow for any thunder, but these could
get quite gusty. Wind Advisory is already in effect for widespread
recurring 40 mph gusts, and any showers could mix down localized 50
mph gusts.
Steep low-level lapse rates in the post-frontal cold advection will
keep the gusts up around 40 mph through about midnight. Valid time
of the wind advisory looks good.
Precip ends and winds slowly diminish after midnight, and Thursday
will be as much below climo as today is above. Leaned on raw model
consensus in the chilly NW flow and substantial cloud cover, which
will limit max temps to lower/mid 50s.
Another frost/freeze on tap for Thursday night into Friday morning,
as the Bluegrass region looks to bottom out around 29-30 degrees.
Recent cold nights have not seen quite the temp crash advertised in
the models, and we don`t have to miss by much to avoid a freeze, so
will hold off on any Freeze Watch for now. However, widespread frost
is possible throughout the area.
.Long Term...(Friday through Wednesday)
Issued at 325 PM EDT Wed Apr 18 2018
Sfc and upper ridging will dominate through the weekend, with the
upper low trying to come out of the Plains remaining well suppressed
to the south. Temps will run on the low side of climo with no
sensible weather impacts beyond increasing mid/high clouds on
Saturday.
Early next week, the upper low tries to lift into the Tennessee
Valley, so precip chances will be on the increase as lobes of
vorticity pinwheel around the closed low. Expect plenty of cloud
cover and off and on precip chances, with temps close to normal for
late April.
&&
.Aviation...(00Z TAF Issuance)
Issued at 740 PM EDT Wed Apr 18 2018
The main concern for this TAF period will be the winds as a cold
front and scattered showers will move through now through 2Z. Behind
the front, winds will shift to WNW. Guidance shows some enhanced
wind gusts right behind this front, particularly at SDF, HNB, and
LEX. After 03-06Z winds will come down a bit, but still be quite
gusty through the remainder of the overnight hours. A stratus deck
will then build in tomorrow morning with MVFR ceilings likely.
Conditions are expected to improve to VFR by tomorrow afternoon with
wind gusts subsiding as well.
.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory until 2 AM EDT /1 AM CDT/ Thursday for INZ076>079-
083-084-089>092.
KY...Wind Advisory until 2 AM EDT /1 AM CDT/ Thursday for KYZ023>043-
045>049-053>057-066-067-078-082.
&&
$$
Update...ZT
Short Term...RAS
Long Term...RAS
Aviation...AMS
Area Forecast Discussion
National Weather Service San Francisco Bay Area
901 PM PDT Wed Apr 18 2018
.SYNOPSIS...A fast-moving weather system will move across the
southern coastal waters tonight bringing a chance of rain mainly
for the southern portions of the Central Coast. A warming trend
and dry weather conditions are expected late in the week and
through the upcoming weekend.
&&
.DISCUSSION...as of 9:00 PM PDT Wednesday...The low pressure
system we have been tracking is localted 150 miles west of San
Francisco and is moving SE at 30 kts. The clouds shield associated
with the low has also tracked SE nearly parallel to the coast. It
now appears the SFO Bay Area will miss out completely on the rain.
The Santa Cruz mountains also looks less likely to get any rain as
well as the interior of Monterey and San Benito counties. The MRY
Bay Area and Big Sur coast still have a chance of getting the
fringes of the rain and even that is in question. Will continue
to monitor the progress of the low pressure system. A couple of
lightning strikes were reported over the outer waters so have
included a slight chance of thunderstorms in the southern coastal
waters but not over land.
The system will quickly move into southern California early
Thursday morning. Dry conditions with slightly warmer temperatures
are expected for Thursday. Surface high builds off the California
coast and ridges into the Pacific Northwest Thursday night and
Friday bringing a light offshore flow while an upper level ridge
moves over the western states. Temperatures will warm up more
significantly Friday and Saturday with highs getting into the mid
80s in the warmest inland locations. This weather pattern then
persists into the first part of next week.
&&
.AVIATION...As of 5:08 PM PDT Wednesday...For 00z tafs. Mid and
high cloud deck is now moving east with vfr skies over the
terminals. Incoming shortwave now expected to mainly impact areas
from kmry southward overnight. Some ifr cigs possible early
Thursday morning, then clearing trend by late morning.
Vicinity of KSFO...Forecast vfr skies this evening and overnight.
Might be some lingering ifr cigs early Thursday morning then
rapid clearing with increasing wnw winds Thursday afternoon.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Latest hrrr model runs only brush
kmry/ksns with -shra overnight, with latest trends keeping precip
just west over the ocean. VFR conditions this evening with
possible showers around 04z. Then some possible lingering low
clouds early Thursday morning before rapid clearing and vfr skies
Thursday afternoon.
&&
.MARINE...as of 3:00 PM PDT Wednesday...A storm system will sweep
through the waters later today and tonight, bringing showers and
possibly a thunderstorm. Winds will increase in the wake of the
cold front and become northwest by Thursday morning. A moderate
northwest swell train will prevail.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm from 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM
&&
$$
PUBLIC FORECAST: W Pi
AVIATION: RWW
MARINE: DRP
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Area Forecast Discussion
National Weather Service New York NY
1059 PM EDT Wed Apr 18 2018
.SYNOPSIS...
Low pressure tracks across the Ohio Valley this evening and to
just south of Long Island on Thursday. The deepening low then
quickly exits into the Canadian Maritimes Thursday night
through Friday. High pressure builds through the weekend and
into early next week. Unsettled weather may return by the middle
of next week as low pressure approaches.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Quick updated to adjust short term temperatures and dew points,
as dew points continue to fall. HRRR slower with the onset of
precipitation and lowered probabilities, especially eastern
zones, through 07Z.
Dew points have mixed out this evening, and were adjusted down
into early this evening. After 00Z dew points will then begin to
climb in the warm air advection and moisture advection ahead of
an approaching shortwave. With increasing clouds and
precipitation onset after 06Z, and continued warm advection,
temperatures look to hold nearly steady, and may even rise. Made
a minor adjustment upward for overnight lows.
Profiles inland saturated and below freezing above the surface.
There may be some wet snow mixed with the rain across the
higher elevations of Orange and Putnam counties, and added a
rain/snow mix. Then mid and upper levels dry after 12Z and
precipitation transitions to all rain.
On the heels of a departing upper low across eastern Canada, a
vigorous shortwave trough at the base of the upper trough will
pivot across the area into Thursday. This will send low pressure
over the Ohio Valley east tonight and then to the south of the
area Thursday morning. Warm advection ahead of the system will
result in increasing clouds this evening with light rain
developing from west to east after midnight.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Periods of light rain will continue for much of the day Thursday
with the highest probability being across the interior where
the better thermal forcing will prevail. As low pressure pulls
to the east by afternoon, wraparound light rain will continue,
tapering off from west to east during the late afternoon/early
evening hours. Rainfall totals for the event will range from
about a tenth to a quarter inch, with the highest amounts across
the interior. As the precipitation winds down, there is the
possibility that a few snow flakes could mix in.
It will be another unseasonably cold day with temperatures
remaining in the 40s, and then dropping into the 30s Thursday
night.
Gusty NW winds up to 30 mph will develop behind the low late
Thursday afternoon/early evening and continue through the
overnight.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Generally tranquil weather is expected during this time frame.
Departing trough to the northeast makes slow progress, with upper
level NW flow continuing across the northeast through the weekend.
Ridge builds across the upper midwest and Great Lakes region, to the
north of southern stream shortwave that passes from the Rockies
through the southern states. The southern stream shortwave, along
with northern stream energy will likely make progress toward the
east coast Tuesday-Wednesday, potentially resulting in unsettled
weather by mid week next week.
Otherwise, dry conditions along with slightly below normal
temperatures are anticipated.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
A wave of low pressure approaches tonight, and passes south of
Long Island Thursday morning, then strengthens as it continues
out to sea during the afternoon.
VFR through at least 06z. Clouds thicken and lower overnight.
There is some uncertainty in when conds drop to MVFR, however
with guidance indicating pcpn slightly delayed from earlier
thinking have sided with the hi-res solutions and delayed MVFR
conds as well. Only have conds dropping to IFR at
KHPN/KSWF/KBDR/KGON where confidence is a bit higher, although
it is a possibility at remaining terminals for at least a couple
of hours Thu. Conds improve back to VFR late from W to E.
P-type could be an issue at KSWF. Soundings indicate a few
hours of SN or RASN until mid levels dry out early Thu morning.
Light and vrb winds overnight, pick up out of the E-NE 5-10kt
towards morning. As the low passes to the south and strengthens
while departing, winds will back to the N then NW and increase
to 10-20g20-30kt in the late aftn/eve.
.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday night-Friday...VFR. NW winds G20-30KT, mainly Thu eve
and after sunrise Fri.
.Saturday-Monday...VFR.
&&
.MARINE...
Wind and seas will subside tonight as low pressure approaches
from the Ohio Valley and passes just south of the waters
Thursday morning. As the low deepens heading up into the
Canadian Maritimes Thursday night into Friday, near gale force
gusts will develop on the waters Thursday evening.
A moderate northwest pressure gradient should allow for SCA gusts 25-
30 kt to continue over the waters on Friday, before diminishing
Friday night.
A small craft advisory has been posted for all the waters
beginning Thursday night and continuing into Friday morning,
except through Friday afternoon east of Moriches Inlet.
The pressure gradient is forecast to relax over the waters this
weekend, becoming light by Saturday night. As a result, sub
Small Craft Advisory conditions are forecast over the waters
around Long Island Saturday-Monday as high pressure builds
closer.
&&
.HYDROLOGY...
Rain amounts below a half inch are expected tonight through
Thursday evening with no hydrologic impacts anticipated. Dry
weather follows thereafter.
There is the potential for significant rainfall mid week next
week.
&&
.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 PM Thursday to 6 AM EDT Friday for
ANZ330-335-338-340-345.
Small Craft Advisory from 6 PM Thursday to noon EDT Friday for
ANZ353-355.
Small Craft Advisory from 6 PM Thursday to 6 PM EDT Friday for
ANZ350.
&&
$$
Area Forecast Discussion
National Weather Service Mount Holly NJ
927 PM EDT Wed Apr 18 2018
.SYNOPSIS...
A area of low pressure will move across the area tonight into
Thursday, along with its associated occluded, warm, and cold
fronts. This low will drift into the Canadian Maritimes through
Friday, which will keep northwest flow across the area with a
couple of dry surface troughs moving across the east coast. High
pressure will build into the Mid Atlantic and Northeast
Saturday through Sunday, before moving offshore Monday into
Tuesday. A coastal low may move north along the coast and affect
the area during the middle of next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
915 pm update: Made some adjustments to temperatures and dew
points overnight, with the former being too warm and the latter
being too cold during the evening hours. Minimum temperatures
were lowered a couple degrees in spots based on input from
high-resolution guidance, though tempered this to some degree
given increasing cloud cover. Tweaked PoPs some more, with
continued trends of the precipitation falling primarily north of
the I-276/I-195 corridors. Thus, I sharpened the PoP gradient
rather considerably overnight.
700 pm update: Main changes to the forecast were to modify PoPs
tonight based on latest hi-res guidance, which generally
indicate a period of light rain/sprinkles/showers from 03Z to
10Z generally north of the I-276/I-195 corridors. The HRRR
suggests a briefer period of rain but potentially with heavier
rainfall rates, whereas the WRF-ARW/NMM and NAM Nest suggest a
longer duration of lighter precipitation. My thinking is that
the briefer duration of the precipitation is more reasonable
(especially given upstream radar trends), though I am not quite
convinced of the wetter solutions yet (despite the rather potent
look to the vort max, along with the close proximity of the
surface low).
Increased PoPs slightly to the north of the I-276/I-195
corridors, but reduced them to the south (and remaining
unmentionable south of an Easton, MD, to Wildwood, NJ, line).
Other main change was to include some chances for (light) snow
to mix in with the rain late tonight in the Poconos (and far
northwest New Jersey), where temperatures will become cold
enough (and profiles will cool sufficiently) for the white stuff
to show up.
Will update storm total snow grids accordingly, though amounts
are expected to be very light (and generally only at the highest
elevations).
Previous discussion...
Surface low pressure will approach the region from the west
tonight, moving into our area late tonight. Cloud cover will
increase quickly tonight as the low moves closer to the area.
Some light rain will fall, in advance of the approaching low but
amounts are expected to remain light, with southern areas
likely remaining dry through daybreak.
Overnight lows will drop into the mid to upper 30s across the
northern zones to mid to upper 40s across the southern zones.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
915 pm update: Lowered temperatures in the northern CWA some
more and increased PoPs north of the I-76 corridor tomorrow, as
there is an increasing signal for scattered to numerous showers
tied to the cold pocket of air aloft collocated with the main
trough moving through. Think the colder model simulations make
more physical sense given the expected regime (and cloud cover).
700 pm update: As the surface low moves offshore tomorrow
morning, should see a brief break in precipitation before
instability showers/sprinkles move in during the late morning
and afternoon as the main trough/vort max move(s) into the
region. Precipitation amounts should be very light (and will
likely be a mix of rain and snow in the Poconos), but would not
be surprised to see some snowflakes mix in with the showers
farther southeast. Trended forecast in that direction a little
bit, but not too much given the expected temperatures/low-level
thermal profiles.
Tweaked PoPs to match the timing of the instability showers, as
depicted by the NAM Nest, WRF-ARW/NMM, and HREF. Also slowed the
onset of the stronger winds by a couple of hours, but did not
change the magnitudes that much given the model-derived mixing
profiles.
Previous discussion...
Low pressure will cross the region tomorrow, dragging a cold
front through during the late morning/early afternoon. Some
light rain will fall across the region as the low crosses the
area. Amounts will be fairly light, especially across southern
areas, with only a tenth of an inch or less expected. As
temperatures cool across the higher terrain, a few flurries or
light snow showers may occur as the precipitation starts to come
to an end toward Thursday evening.
Extensive cloud cover across the northern half of the forecast
area will keep much cooler and only into the upper 30s to mid to
upper 40s. Once you get down towards Philadelphia and points
south, skies should see a few breaks. Highs into the upper 50s
to lower 60s are expected.
Even with the sun peeking out, it will feel cooler through the
day as the winds will really start to ramp up by late
morning/early afternoon. Winds will be our of the north to
northwest at around 15 to 25 mph with gusts up to 35 mph
possible.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
A quiet start to the extended forecast for the end of the week,
through this weekend, into early next week. A return of
unsettled weather is possible by the middle to end of next week.
On Thursday night, the low pressure that affects the area
during the day will continue to move northward into the Canadian
Maritimes. Most of any precipitation associated with the low
will move to our north with the low pressure. However, there
could continue to be some snow showers across the higher
elevations, especially during the evening hours as the low-mid
level lapse rates may be high enough to interact with some left
over moisture and the passing short wave. These showers will
dissipate through the night into Friday morning as the moisture
dissipates across the area.
On Friday, the low will remain across the Canadian Maritimes,
while surface trough will likely cross the area. The trough will
be dry, and only present a shift in wind direction and possibly
some cloud cover, as it will likely not having much of an
airmass change. Winds during the day will be generally out of
the northwest, and gust 25- 30 mph, occasionally up to 35 mph at
times. Dry and breezy conditions will continue into Friday
night as well.
On Saturday, dry conditions will continue as another dry
surface trough will move across the area, before high pressure
builds into the area overnight. Winds will gust around 20 mph at
times, but it will not be as windy as Friday.
High pressure builds across the Mid Atlantic and northeast
Sunday, before moving offshore my Monday. Dry conditions will
continue for Sunday and Monday.
As we move into Tuesday and Wednesday of next week, a coastal
low is forecast to lift northward along the east coast. There is
timing differences between the GFS, ECMWF, and Canadian. With
the timing differences, there is the potential for rainfall
starting as early as Tuesday, with the most likely period
looking to be Wednesday Wednesday night. Temperatures across the
area are forecast to be above freezing, so the precipitation
would be all rain.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...VFR to start with, but CIGs are expected to develop
rapidly and descend after 03Z. By 09Z, may see RDG/ABE flirt
with MVFR criteria. Light rain or showers are forecast
near/north of RDG/ABE/TTN, but may have a difficult time
reaching PNE/PHL/ILG and are not expected to affect MIV/ACY. Low
VFR to MVFR expected at most sites by daybreak. Winds will
become light/variable quickly this evening. Moderate confidence.
Thursday...Low VFR to MVFR conditions are anticipated at most
sites, especially during the morning, as drizzle/patchy fog may
occur near RDG/ABE/TTN and light showers subsequently move
through the Philly terminals northward and westward through mid
afternoon. CIGs will likely rise a little bit during the
afternoon as winds become westerly/northwesterly and gusty by
late morning and continuing during the afternoon (10-20 kts with
gusts 25-30+ kts). Moderate confidence.
OUTLOOK...
Thursday night...MVFR conditions possible early, before
improving to VFR overnight. Gusty northwest winds 20-30 knots.
Friday-Monday...VFR through the period. Gusty northwest winds
20-30 knots Friday; 20-25 knots Friday night; and 15-20 knots
Saturday.
&&
.MARINE...
Gale watch for southern NJ/DE Atlantic coastal waters and for
Delaware Bay was upgraded to a gale warning from 2 pm Thursday
to 8 am Friday. Gale watch remains in effect for the
northern/central NJ waters, where confidence is a little lower
on gusts meeting criteria (and potentially for a little bit
later of an onset, given the latest model guidance).
Previous discussion...
Tonight...Quiet conditions on the area waters with southerly
winds around 10 to 15 knots and seas around 2 to 4 feet.
Thursday...Winds will pick up out of the northwest on Thursday
and become particularly gusty during the afternoon and evening.
Soundings show a strong, deep layer of 35+ knots over the area
waters and mixing should be fairly efficient by the afternoon.
Sustained winds of 15 to 25 knots with gusts up to 35 knots.
Seas will also increase to around 4 to 5 feet by Thursday
afternoon.
OUTLOOK...
Thursday night...Winds could gust up to 35 knots through the
night.
Friday-Friday night...Small Craft Advisory conditions likely.
Saturday-Monday...Sub Small Craft Advisory conditions exected.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Gale Watch from Thursday afternoon through Friday morning for
ANZ450>452.
Gale Warning from 2 PM Thursday to 8 AM EDT Friday for ANZ430-
431-453>455.
&&
$$
Synopsis...Robertson
Near Term...CMS/Meola
Short Term...CMS/Meola
Long Term...Robertson
Aviation...CMS/Robertson/Meola
Marine...CMS/Robertson/Meola
Area Forecast Discussion
National Weather Service Blacksburg VA
944 PM EDT Wed Apr 18 2018
.SYNOPSIS...
Low pressure will move through the middle Atlantic region and
push a cold front through the Appalachians and central mid
Atlantic region. This will bring very windy conditions, along
with much colder temperatures, along with some showers west of
the Blue Ridge and even some west snow for the higher
elevations. High pressure then builds in with fair conditions
and slightly warmer temperatures into the weekend.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 944 PM EDT Wednesday...
Modified temperatures this evening into tonight utilizing the
latest surface obs, their trends and shaped towards GLAMP.
Made some minor changes in pops and weather blending in the
HRRR. Timing of showers by 06z in the west, stills looks
reasonable. However, convection will weaken as it moves
towards our forecast area. Wind advisory on track for
overnight into Thursday along and west of the BLue Ridge.
Post frontal winds will be gusty supported by strong cold
advection.
As of 744 PM EDT WEdnesday...
Wind advisory for post frontal winds from the Blue Ridge
westward looks good. Made some minor adjustments in temperatures
for this evening into tonight. Convection along the cold front
appears limited this evening. However, HRRR and Highres models
still support current pops in the west. The best chances are
along the far west mountains with upslope enhancement late
tonight into Thursday.
As of 225 PM EDT Wednesday...
Low pressure will move through the middle Atlantic region and
push a cold front through the Appalachians and central mid
Atlantic region. This will bring an abrupt end to our one day
of spring as much colder air moves in on strong gusty northwest
winds. Expect rain showers with the front west of the Blue Ridge
to transition to upslope rain/snow showers on Thursday with
some minor snow accumulation for the higher elevations. The
upslope precipitation will be decreasing during Thursday
afternoon.
The winds behind the front will become quite strong as cold air
advection creates efficient downward momentum transfer with
gusts around 50MPH at the higher elevations from the Blue Ridge
westward starting around Midnight and continuing through
tomorrow. Gusts will not be quite as strong east of the Ridge
and will generally wait for the arrival of netter mixing with
diurnal heating by mid/late morning.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 300 PM EDT Wednesday...
Models agree on continuation of stronger winds at least until
midnight Thursday night, especially along the Blue Ridge as 45 kt
jet shifts toward the southern Shenandoah Valley.
Expect some linger flurries in western Greenbrier, then dry, sunny
and cool Friday. May have some freeze issues late Thursday night but
no frost as RH only recovers to 60-65 percent and winds will be
blowing.
Highs Friday will be in the 50s in the mountains, with even some 40s
in the higher ridges of the Alleghanys, to lower to mid 60s across
the foothills/piedmont.
May have more of a freeze/frost issue late Friday night, especially
in the southern Shenandoah Valley as winds drop off and temps drop
to near freezing. No headlines at this point.
Saturday, the surface high continues to build in from the Great
Lakes providing sunshine and warmer highs in the 60s.
Clouds increase ahead of the upper system moves into the lower MS
valley.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 145 PM EDT Wednesday...
Going to be wet/cool but not cold period, as upper low develops over
the lower MS Valley Sunday and pushes across the northern tier of
the Gulf Coast states Sunday afternoon into Tuesday. Models have
trended north, but would like to see more consistency in them, as a
further south track would lead to dry/cool with more sun while north
would be wetter/cloudier but still a bit on the cool side.
For consensus, models are showing more of cloudy pattern with threat
of rain each day. As the low moves off the coast Wednesday, a
northern stream front shift in from the northwest with another
threat of showers.
Sunday appears the drier of this period with increasing clouds.
Highs will range from the mid 50s to lower 60s mountains, with mid
to upper 60s in the piedmont/foothills, which is about 5 degrees
below normal.
Lows will be close to normal during the week with mid 30s to lower
40s west, to lower to mid 40s east.
Highs Monday-Tuesday will be around 10 degrees below normal, ranging
from the lower to mid 50s west, to upper 50s to lower 60s east.
May be a little warmer Wednesday ahead of next front with upper 50s
to lower 60s mountains, to mid to upper 60s east.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
As of 730 PM EDT Wednesday...
Low pressure with a trailing cold front will move east though
the Mid Atlantic region tonight into Thursday. VFR condition
will continue this evening into tonight. Overnight into Thursday
Taf locations west of the Blue Ridge will trend to generally
MVFR, possibly IFR, as the front brings upslope showers to the
region. Colder air moving in will gradually mix/change to snow
showers. Don`t expect much spill over past the Ridge so will
maintain a VFR forecast in the east.
Conditions will become quite windy behind the front as cold air
moves in and makes for efficient momentum transfer of vigorous
low level winds to the surface. Expect the strong gusts to make
their way east of the Blue Ridge primarily with onset of heating
and better diurnal mixing. Gusts AOA 40kts can be expected
along/west of the Blue Ridge, around 30kt to the east.
High confidence in ceilings, visibilities and winds during the
taf period.
Extended Aviation Discussion...
VFR returns Friday although gusty north winds to persist as
high pressure slowly builds in from the northwest. Winds should
diminish by Saturday with VFR ceilings and visibilities.
Clouds will begin to creep back into the area on Sunday in
advance of an approaching low in the Lower Mississippi River
Valley. However, cigs should remain VFR while the ceiling heights
lower and clouds thicken. SCT MVFR showers are possible in
southern Virginia and northern North Carolina Sunday night into
Monday morning.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Wind Advisory until 6 AM EDT Friday for VAZ007-009>020-022>024.
NC...Wind Advisory until 6 AM EDT Friday for NCZ001-002-018.
WV...Wind Advisory until 6 AM EDT Friday for WVZ042>044-507-508.
&&
$$
SYNOPSIS...MBS
NEAR TERM...KK/MBS
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/KK/MBS