Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/21/21
Area Forecast Discussion
National Weather Service State College PA
1122 PM EDT Tue Apr 20 2021
A stalled front draped across northern Pennsylvania will keep a
tight temperature gradient in place across the region this
Later tonight, an approaching low pressure system will track
along the aforementioned front, bringing some accumulating snow
to the northwest mountains. Big changes arrive on Wednesday as a
strong cold front sweeps through the Commonwealth, potentially
creating a few strong to severe thunderstorms during the day and
ushering in plummeting temperatures overnight.
Near or below-freezing temperatures Thursday morning will
precede a gradual warmup through the weekend. Dry weather will
prevail Friday into the first part of Saturday. Some showers
will be possible later Saturday into Sunday. Dry weather will
return for Monday into Tuesday.
.NEAR TERM /THROUGH WEDNESDAY/...
A weak shortwave lifting into the region is supporting developing
showers along and north of a stalled frontal boundary, which
lies across the southeast part of the forecast area. The latest
RAP shows a fairly impressive low level jet overrunning the
front late this evening. All near term guidance supports bumping
POPs up this evening from the south central mountains northeast
through around KIPT.
By late tonight, surface low pressure will develop over the
middle and Upper Ohio River Valley in response to increasing
large scale lift beneath the right entrance region of a 90 kt
upper jet just to the north of PA and 130 meter 500 mb height
fall center headed our way from Indiana/Illinois. This system
will have enough cold air across the northwest mountains PA to
produce some wet snow tonight - perhaps a few locations
surpassing the 3inch mark in far NW Warren county, but probably
nothing as far south as I-80. Model soundings also indicate a
brief period of freezing rain or sleet is possible over the
northern mountains late tonight, although accumulation will be
insignificant and impacts non-existent owing to warm antecedent
As low pressure moves northeastward off the coast, a strong cold
front will sag southward across the Commonwealth during the day
on Wednesday. This cold front will traverse the Susq Valley
during the late morning hours with the western edge of any
appreciable ML CAPE likely impacting just our far eastern zones
like SE York, Schuylkill, Lancaster and Lebanon counties where a
few TSRA are expected and SPC has a MRGL Risk for SVR painted.
By the time the cold front passes through, rainfall totals are
forecast to be less than 0.10 inch across the Laurels and south
central PA, with 0.10 to 0.40 inch of precip expected north of
I-80. This precipitation should help put a dent in the ongoing
drought conditions in the northwest mountains.
In the wake of the cold front, plummeting temperatures and
gusty winds will spell a noticeably chilly afternoon. Winds will
gust over 30mph south of I-80. Daytime highs will occur ahead
of this front in the southeast zones, topping out in the low 60s
by about 11AM. By nightfall tomorrow, temperatures will range
from the mid 30s across the northwest to near 50 in the
southeast with wind chills well down into the 20s. The NW flow
will also bring in the return of lake effect showers, which will
mix with snow before nightfall in the west and turn to plain
snow showers early Wed evening.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
Lingering lake effect and upslope snow is likely to result in a
fresh coating of accum across the north and Laurels Wed night,
esp on the higher elevations.
Temps will continue to cool with mins in the mid 20s to low 30s
by Thursday morning. With another group of south central PA
counties scheduled to begin their growing season on Apr 21, we
will have to monitor low temps for freeze warning criteria Thu
AM. It does look like it will be too windy for frost formation.
Thursday will be another blustery day with gusts into the 30s
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
10 pm Tuesday update... Our various ensemble prediction systems
are in good agreement on the large-scale pattern into next week.
There will be a tendency for upper troughiness to persist over
eastern Canada and the northeastern U.S. through the upcoming
weekend, followed by height rises early next week, as an upper
low is forecast to shift eastward from the Canadian Maritimes
into the north Atlantic. In general, this set up will produce
near to below average temperatures for late April across the
Commonwealth through Sunday, with some moderation likely for
the early and middle portions of next week.
After a cold night Thursday night, Friday should feature a fair
amount of sunshine, but with readings still somewhat below
normal (highs in the 50s-lower 60s). Much of Saturday should
remain dry, with highs generally in the 60s. A period of rain
appears likely Saturday night into Sunday, as a well formed
upper trough crosses the Commonwealth, and an intensifying
surface wave rides up the eastern seaboard.
Next week, things should dry out, with temperatures on the
rebound. In fact, by Tuesday, depending on the ultimate position
of a warm frontal boundary, highs could pop back into the 70s
for at least portions of south-central PA.
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
00z update... A broken band of showers/isolated thunder has
developed early this evening along a frontal boundary draped
across PA. A near-term threat of thunder in the vicinity of KIPT
through 01-02z, with generally VFR elsewhere.
Later tonight (after 06-08z), ceilings should lower into the
fuel alternate-IFR categories, with a period of snow early
Wednesday at KBFD.
Surface winds turn NW and become quite gusty during the day
Wednesday well behind the cold front. Frequent IFR snow showers
are foreseen at KBFD and KJST, with conditions gradually
improving to VFR elsewhere by afternoon.
Thu...Northwesterly flow, with restrictions and spotty rain or
snow showers N/W PA.
Fri...Still windy early, but mainly dry.
Sat...Restrictions possible as rain approaches from the SW late.
Sun...Widespread showers, tapering off late.
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
906 PM CDT Tue Apr 20 2021
905 PM CDT
The going forecast and message are both in good shape through
tonight and rolling into Wednesday. Did hang onto some snow
showers/flurries through later tonight, and have boosted
Wednesday afternoon PoPs further over far northeast Illinois.
Scattered showers -- primarily snow showers -- continue to fester
this evening across the area, with the greatest coverage 20 miles
east/west of I-55 as of 9 PM. These are persisting under a 500 mb
vorticity maximum and upper level jet streak moving slowly
eastward. These showers should very gradually fade into the
overnight, however some light snow/flurries may redevelop in
northeast Illinois under subtle isentropic ascent late tonight.
With near record seasonal cold 850 mb temperatures of -6C to -8C,
much of the cloud cover has been more closed-celled cumulus and
lingering longer after dark. This should prevent surface
temperatures from dropping too much, however readings are already
in the 30s in most areas so it remains on track to drop below
freezing. Some clear pockets could develop and within these holes
are where a hard freeze would be most favored, primarily in
outlying locations. So no changes made to current Freeze Warning.
Looking upstream, the well-defined closed upper low across
eastern South Dakota/western Minnesota is slowly moving southeast
with an area of moderate to briefly heavy snow showers. The 00Z
ABR sounding showed steep lapse rates through 600 mb due to 700 mb
temperatures of -20C (near or record cold for this time of year).
The forecast RAP and HRRR soundings for northeast Illinois
Wednesday afternoon resemble this observed sounding, and so would
expect similar behavior to what was observed in that area this
afternoon and early evening (scattered moderate-heavy snow
showers). Northeast Illinois remains the most favored area both
synoptically in the mid-levels (PVA) and also on the mesoscale in
the low-levels (wind convergence and surface-based positive
CAPE). Have increased the PoPs in Lake and Cook Counties since our
confidence has increased, and because of the convective nature
seen upstream and shown in guidance, have added heavy mention to
account for the likelihood of temporary very low visibility in
heavier snow/graupel rates.
325 PM CDT
Through Wednesday night...
Our primary band of frontogenetically driven moderate snow is now
shifting over my far southeastern counties in east central IL and
into parts of northwestern IN. Expect this band of snow to continue
to shift out of this area early this evening. Otherwise, some
scattered snow showers will persist this afternoon and into the
evening, primarily over inland areas of northern IL west of the
immediate Chicago area as a weak surface trough drops southward over
the area. The combination of steep low-level lapse rates and some
modest boundary layer convergence with this trough into this evening
may support some brief localized bursts of snow with these showers,
but no more than a coating on grassy surfaces is anticipated. This
activity may begin to wane overnight, before additional snow showers
develop for Wednesday.
In spite of the cloud cover across the area for most of the night,
temperatures are still expected to fall below freezing tonight in
most locations, and few areas could drop into the upper 20s. For
this reason, we have made no changes with the going freeze warning
Main concerns are with snow/graupel showers and gusty squalls
along with isolated thunderstorms during the day on Wednesday and
then another freeze late Wednesday night, mainly outside downtown
There are a few good analogs for the synoptic set-up tomorrow,
namely April 2, 2016 and October 20, 2018, which both had
scattered to numerous snow/graupel showers and squalls. A strong
500 mb vorticity lobe on the west side of unseasonably deep and
cold upper low over the eastern Lakes will pivot across the area
from the late morning through mid afternoon. 500 mb temps of -30
to -35C, essentially off the charts cold per late April sounding
climatology, and the strong mid-late August equivalent sun will
yield very steep low and mid-level lapse rates, nearly dry
adiabatic in the 0-3km layer. Forecast soundings indicate an
inverted V look roughly in that layer.
The result will be a couple hundred J/kg of SB CAPE and some DCAPE
as well. A strong lake enhanced convergence axis will set up
across northeast Illinois and northwest Indiana to provide a low-
level focus for the large scale lift from the vort lobe.
Anticipating convective processes to get going pretty quickly
during the morning. With wet bulb zero heights below 1kft AGL and
the very dry sub-cloud layer, despite temps getting up into the
40s outside convection, expect much of the showers to feature snow
and graupel as temperatures under them rapidly cool down into the
30s. Most widespread/numerous coverage is forecast to be in the
aforementioned lake enhanced convergence axis toward mid day and
through mid afternoon. Strong large scale and mesoscale lift and
convection will yield at least isolated embedded heavy
showers/squalls, with low freezing levels supportive of isolated
lightning strikes and graupel.
Looking back to the 2016 and 2018 events, the heaviest squalls had
brief heavy snow/graupel with very poor visibility and strong
wind gusts, along with a few lightning strikes. Primary difference
between those events and tomorrow is weaker wind fields aloft.
That said, the deep mixing, steep low level lapse rates, and DCAPE
should support gusts up to 30-40 mph in the heaviest squalls,
which would knock down visibility farther. Even with the highest
shower coverage closer to Lake Michigan, still expecting scattered
coverage inland given the good large scale lift. Wouldn`t be
surprised to see a quick couple tenths of snow under heavy
snow/graupel squalls, though mild pavement temps should keep the
impacts mainly as brief low to poor visibility and rapidly
325 PM CDT
Wednesday Night through Tuesday...
Large scale upper trough is progged to be moving off to the east of
the area Wednesday night, though with one last smaller scale short
wave rotating east-southeast into the departing trough axis. Cold
mid-level temps associated with this wave/departing upper trough
(around -22C depicted at 700 mb) combined with a deeply mixed
boundary layer (adiabatic lapse rates from the surface up to 700 mb)
will likely continue to support isolated to scattered convective
rain/snow showers early Wednesday evening.
Loss of diurnal low level instability and passage of the short
wave trough axis should allow these showers to dissipate by late
evening, with subsidence developing across the region after
midnight and inducing clearing skies. Clearing within the cold
airmass is expected to aid in producing widespread freezing
temperatures across the forecast area, with lows in the upper
(locally mid) 20s outside of the core of the Chicago metro area
by sunrise Thursday, with low-mid 30s in the city. We`ll very
likely need freeze warning headlines again for Wednesday night,
but for simplicity at this time we`re continuing to mention the
Wednesday night impacts in the additional information section of
the current headline in effect for tonight.
Mid-level short wave ridging then develops across the area Thursday
into Thursday night in the wake of the departing upper trough.
Strong 500 mb height rises in excess of 80 meters is progged across
the area initially Thursday, indicative of deep large-scale
subsidence. Along with very dry thermodynamic profiles, subsidence
should promote plenty of sunshine across the area and allow a quick
rebound of temperatures back into the mid to upper 50s, and somewhat
breezy west winds limiting lake breeze potential. Guidance remains
in general agreement in depicting a low-amplitude mid-level short
wave approaching the mid/upper Mississippi River valley later
Thursday night, which would likely bring increasing high cloud cover
into the region after midnight. Lows will likely dip into the 30s
outside of Chicago in the dry air mass prior to the arrival of
high clouds however, possibly producing some patchy frost into
This mid-level wave is then progged to dampen across the region
Friday, as it propagates into the upper ridge position. Low level
return flow develops across the Plains in association with this
feature, but becomes weaker and less-focused as the amplitude of the
disturbance decreases across our area. Lower and mid level southwest
flow does provide warm/moist advection into the region by Friday
afternoon however, with NCEP guidance depicting the potential for
spotty showers across interior northern and central Illinois
later in the afternoon. Certainly possible per ECMWF that the
lower and mid-level dry air hangs tough through the day though.
Global models continue to show some differences with a couple of
additional short waves within developing northern and southern
streams Friday night into Saturday, though the general consensus
remains for shower chances to persist into the day Saturday as
these waves move east and a cold front associated with the
northern stream wave pushes through the area. Temperatures do
continue to moderate Friday into Saturday with southwest low level
flow, though this will likely be modulated by increased cloud
cover and a potentially stronger southern stream low as again
noted in the ECMWF and ECS ensemble runs. Highs both days should
be near 60, and possibly into the mid-60s on Friday if cloud/shower
coverage are lower than forecast. A stronger southern stream low
per the ECMWF would also result in a greater potential for
onshore surface winds and cooler temps off of Lake Michigan
however on Saturday.
Both of these short waves and their developing larger scale upper
trough are progged to move off to the east of the area Saturday
night with a broad, flat upper ridge depicted across much of the
central CONUS by Sunday. Associated surface high pressure moves
across the forecast area during the day, allowing dry weather and
likely some lake cooling (upper 40s to around 50) with temps in
the 50s to near 60 inland expected to round out the weekend. Upper
ridge is then progged to amplify across the central CONUS/Midwest
early next week, in response to an upstream long wave trough
moving into the West Coast. Developing southerly flow behind a
warm front lifting into the region should support warmer temps
(perhaps 70s) by Monday, with the best potential for warm
advection showers/storms currently looking to remain off to our
northwest through the day on Tuesday. That said, precip chances
aren`t zero on Monday, with ECMWF showing spotty elevated
convection tied to the lifting warm front.
At this vantage point, Tuesday currently looks breezy and warm
(near/around 80F) and most likely capped to convection through
the daylight hours. A rather potent system could take shape from
the ejecting western trough beyond day 7, with shower/thunderstorm
chances a decent bet.
For the 00Z TAFs...
Aviation weather concerns this period consist of:
* Low threat for BR/low cig re-development late tonight, as well
as a -SHSN or two
* Developing gusty northwest winds through Wednesday morning and
* Convective rain/snow/graupel showers into Wednesday afternoon,
especially across northeast IL/northwest IN with some lightning
* Northeast winds into ORD/MDW/GYY late in the afternoon
Spotty -SHSN continue away from the terminals early this evening,
and anticipate this will remain the case as drier air has filtered
across the Chicago-area sites. Hi-res guidance is suggesting that
some of the low cigs currently across central Illinois may drift
back northward late tonight/Wednesday morning as the low-level
flow veers. Confidence in this occurring, or resulting in low cigs
and some light BR was too low to justify a formal mention in the
outgoing TAFs, but we`ll continue to keep an eye on trends.
A weak disturbance will pass overhead in the 10-15z time frame.
It`s possible this results in some very spotty precipitation
(-SHSN) but again coverage and confidence remains under 30% at
this time. Breezy northwest winds will develop through Wednesday
morning and afternoon, with a lake-enhanced boundary expected to
develop with time. As a result, a northeast wind shift will likely
remain in very close proximity to ORD/MDW, lending low confidence
in the wind trends into the early afternoon, with better
confidence in a northeast wind shift late in the afternoon.
A deeply-mixed environment will result in pockets of sufficient
instability for electrification as precipitation develops
Wednesday morning and afternoon. Have maintained the inherited
VCTS during the 18-23z window due to this potential, as well as
the likelihood of convective tops in the vicinity. Temperatures
will warm into the 40s, but the convective nature of activity will
likely support frozen precipitation, but little/no accumulations
are expected given the temperatures. Precipitation will wane into
Wednesday evening with the loss of daytime heating.
ILZ108...midnight Wednesday to 9 AM Wednesday.
Wednesday to 9 AM Wednesday.
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Updated for 00Z Aviation Forecast Discussion below.
PREV DISCUSSION... /issued 250 PM CDT Tue Apr 20 2021/
Much of the CONUS will remain under the influence of a longwave
trough over the next several days. This trough will bring near
record cold and a potential frost/freeze to portions of the Mid-
South late tonight and possibly again Wednesday night. A sharp
cold front currently extends from west-central AR, across
southeast AR, and along the OH River. Temperatures behind this
front are in the 40s and 50s, while areas in the warm sector are
currently in the 70s.
This front will sweep across the Mid-South overnight. Gusty
northwest winds are expected in the wake of this boundary with
gusts of 25-30 mph for a few hours. Strong cold advection will
usher in much colder air, with temperatures falling into the 30s
across most of the CWA by sunrise. A light freeze is expected
across northeast AR into far northwest TN, but it does look to be
confined to a brief period around 12z. Surface winds of 5-10 mph
may result in sufficient mixing to limit significant damage to
vegetation, but protective actions are recommended. This freeze is
marginal and all areas in the warning may not reach 32F, but I
prefer to err on the side of caution given the given the state of
the vegetation and the date.
Scattered showers are likely ahead of this front from late this
afternoon into the overnight hours. mPing reports upstream over
the higher terrain of the Ozarks are either all snow or a mix of
rain/snow. Point soundings along the northern tier of counties in
the Mid-South are supportive of a mix of rain/snow overnight.
That said, warm ground and low QPF will result in no accumulation.
This activity will end from west to east overnight, with nil PoPs
Transient shortwave ridging behind the departing trough will lead
to dry weather on Wednesday and Thursday but temperatures will
remain well below climatology. Highs on Wednesday are expected to
remain in the 50s with many areas warming back into the low/mid
60s for Thursday. A frost is possible for some areas across the
Mid-South early Thursday morning. A 1028 mb anticyclone will
build over the Mid-South, resulting in light winds and dry air.
However, increasing mid/upper-level cloud cover could preclude a
full decoupling of the boundary layer and may keep temperatures
just warm enough to limit this frost potential. The main area of
concern will west TN and northeast MS where cloud cover would
arrive later. MOS continues to indicate minimum temperatures of
32-36F while the blends favor a warmer solution. Given the track
record of model guidance in radiational cooling scenarios, I`m
trending in the cooler direction (at least for the areas that
remain mostly clear). No headline will be issued at this time for
Thursday morning, but one may be necessary eventually.
The trough that is forecast to affect the Mid-South late week
looks to weaken as it moves across the area before eventually
phasing with the northern stream over the Mid-Atlantic region.
Showers, and a few thunderstorms, are expected Friday into
Saturday, but the severe weather threat will likely be confined
to the Gulf coast. Rainfall amounts exceeding 1" are most likely
across north MS. The air mass associated with this wave will be of
Pacific origin and should actually be warmer than what it is
replacing. Thus, expect pleasant weather Sunday into Monday with
temperatures climbing back above climatology by the latter.
A deep trough is poised to affect the area midweek. The 12z
deterministic global models (as well as their ensemble means)
build a ridge up the east coast ahead of this trough. This causes
the trough to slow and lift more northeast as it moves out of the
Plains. We`re looking at an increasing potential for showers and
thunderstorms to round out the forecast period, but the severe
weather threat will be significantly influenced by the strength of
the East Coast ridge. We`ve got plenty of time to assess this
Primary concern is winds this evening. Following frontal passage,
observed gusts have been in line with guidance. KNQA VAD wind
profiler showed winds 34030KT between FL020-030. This should
represent the maximum gust potential through 03Z or so.
Thereafter, low level pressure gradient and pressure advection
will ease up, likely limiting MEM gust potential by 08Z.
A narrow band of MVFR ceilings may be accompanied by -SHRA at
MEM, and perhaps a brief -SHRA/SN mix at MKL late this evening.
AR...Freeze Warning from 3 AM to 9 AM CDT Wednesday for Clay-
MO...Freeze Warning from 3 AM to 9 AM CDT Wednesday for Dunklin-
TN...Freeze Warning from 3 AM to 9 AM CDT Wednesday for Dyer-Lake-
Area Forecast Discussion
National Weather Service San Francisco Bay Area
625 PM PDT Tue Apr 20 2021
.SYNOPSIS...A slight chance of showers or an isolated thunderstorm
across the hills of Napa and northern Sonoma county late this
afternoon through sunset. Otherwise clear to partly cloudy and
seasonably cool overnight. Dry and seasonal weather returns
Wednesday through Friday. Increasing clouds Saturday leading to a
chance of rain by Sunday.
.DISCUSSION...as of 2:21 PM PDT Tuesday...Low clouds have
lingered into the afternoon around SFO as well as coastal San
Mateo and the Monterey Bay region. Inland skies have cleared but
temps remain coolish in the 60s and lower 70s with brisk onshore
winds. The onshore winds are being amplified as a potent shortwave
trough drops southward over the Central Valley this afternoon.
SFO has been gusting in excess of 35 mph with gale force gusts
noted at several of the coastal buoys. This upwelling has dropped
sea surface temps into the upper 40s, thus the chilly temps at
area beaches as clouds and onshore breezes persist.
Short term focus from now through about sunset will be possibility
of showers and isolated t-storms, mainly around Mt Saint Helena
and the higher terrain of northern Napa county. Satellite imagery
shows cumulus clouds rapidly starting to develop as potent
shortwave and associated steep lapse rates will allow for rapid
destabilization over the next several hours. Usually under these
type of events the precip stays over Lake County and points
northward. However, the shortwave is progged to drop right down
the Central Valley. Thus orographics, afternoon heating and
dynamic forcing all coming into play. Mesoscale model simulations
such as HRRR and RAP keep showing activity this evening so
confidence is higher than normal that well see some
showers/t-storms. Rainfall amounts shouldn`t be too heavy with
main concerns for some small hail, gusty outflow winds and
possible lightning strikes. Cant completely rule out new fire
ignitions with any strikes but that is remote possibility and low
chance scenario. Again, nearly all areas will remain dry and the
above covers mainly the higher terrain of Napa and extreme
northeast Sonoma county through sunset.
The shortwave will quickly move east of the region by Weds
morning. This will leave the area in a seasonable weather pattern
with dry weather except for coastal drizzle. Northerly flow behind
the trough may bring the most warming to the North Bay with temps
back into the 70s and lower 80s. Other portions of the Bay Area
may not be quite as warm as westerly onshore winds will prevail
through the end of the work week with highs 60s and 70s.
Saturday should see increasing clouds with onshore winds as
temperatures cool slightly ahead of incoming late season trough.
Ensembles and deterministic models in good agreement that a fairly
strong late season cold front will bring rain to the region on
Sunday. System will be dropping out of the Gulf of Alaska and be
fairly fast moving which will limit rainfall totals. Nonetheless
early estimates suggest 0.25-0.50 potential for much of the Bay
Area with higher amounts North Bay hills and Santa Cruz mountains.
No, not nearly enough to make much of a dent for the ongoing
drought. However, snow in the Sierra with a solid wetting rain
would at least slow the onset of fire season which is a good
thing. Will continue to monitor and update over the coming days.
.AVIATION...As of 06:30 PM PDT Tuesday...For the 00Z TAFs.
Widespread MVFR at several of the Bay Area and Central Coast
terminals this afternoon with cigs between 1500-2000ft. Strong
onshore flow also being observed regionwide as a low pressure from
the north increases the north-south gradient and produces 20-25kt
winds with occasional gusts >30kts along the San Bruno Gap.
Thunderstorms have also been approaching the KAPC terminal this
afternoon but have gradually weakened on their approach so only
expecting VCSH at KPAC along with a slight chance for some
isolated showers to approach KSTS. Showers are not expected to
survive beyond the North Bay terminals this evening. Marine
stratus will persist this evening and reintroduce MVFR to many of
the coastal and interior terminals tonight and into tomorrow
morning owing to the enhanced onshore flow from the low pressure
system to our north increases the SFO-ACV gradient. The exception
will be the North Bay terminals, as drier offshore winds (N/NE)
following the passage of the low pressure system will impede
marine stratus development and intrusion north of the Golden Gate.
Vicinity of KSFO...MVFR conditions with BKN skies at the KSFO and
KOAK terminals along with strong onshore winds between 20-25kts at
KOAK and gusting to 40-45kts at times at KSFO. Will see a gradual
decrease in wind intensity after 9Z as the low pressure to our
north begins to exit the region, but the strong onshore push from
the day will allow for the continuation of stratus intrusion
through the overnight and into tomorrow morning. Ceilings will
improve by daybreak (mixed MVFR and VFR) and will observe a lull
in winds through much of the morning but winds onshore flow will
pick up to 10-15kts by the end of the TAF period.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...MVFR/IFR with clouds likely remaining
around terminals through the day. -RA/DZ will be intermittent
this afternoon for KMRY. Winds will be onshore and gusty through
most of the TAF period. Winds will eventually subside late in the
TAF period and any terminals that saw brief clearing will return
to MVFR conditions with cigs between 1000-1500 feet.
.MARINE...as of 01:17 PM PDT Tuesday...Currently strong northwest
winds with gale force gusts over the northern waters and down the
Big Sur coast today. These strong winds in the northern waters
will combine with a northwest swell to produce steep seas 11 to
13 feet at 11 seconds this afternoon and evening, resulting in
hazardous seas conditions particularly for smaller vessels. The
gusty winds are expected to persist through tonight. The
northwest swell continues through the week.
.Tday...SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
GLW...Pt Arena to Pigeon Pt 10-60 nm
GLW...Pt Arena to Pt Reyes 0-10 nm until 9 PM
GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm until 9 PM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 9 AM
SCA...Mry Bay until 9 PM
SCA...SF Bay from 2 PM
PUBLIC FORECAST: RWW
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