Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/17/19
Area Forecast Discussion
National Weather Service Caribou ME
1057 PM EDT Wed Oct 16 2019
Low pressure will intensify off the Mid-Atlantic coast overnight
and quickly track north into New Hampshire Thursday morning.
The low will weaken and slide east across southern Maine
Thursday night and into the Maritimes on Friday. High pressure
will return through the weekend and into Monday.
.NEAR TERM /THROUGH THURSDAY/...
1040 PM Update... High clouds moving ne across the CWA w/lower
clouds moving into southern areas. The RAP continues to handle
this well showing deeper moisture to the south at 02z. Rain
showing up across southern Maine and spreading north. No changes
were made to the rain chances for the overnight and things
appear to be working out ok. Temps were updated to match the
latest obs. Headlines remain in place.
An upper trof/low ovr the lower great lks will be taking a
negative tilt ovrngt ovr the mid Atlc states. This will allow
rapid secondary cyclogenesis ovr the mid Atlc states this eve,
with the low movg N into W cntrl New Eng by erly morn Thu, at
which tm the sfc low will be captured by an upper low, with both
systems then movg E ovr coastal Downeast ME by Thu erly eve.
From a sensible wx perspective, this will result in increasing
cldnss for our FA this eve, with rn onset advcg SW to NE across
the FA from late tngt ovr the lower Penobscot vly to erly to
mid morn ovr the Nrn St John vly. With the low reaching max
intensity late tngt, then slowly filling durg the day Thu, best
hvy rn banding will be ovr Srn and Wrn ptns of the FA late tngt
into Thu morn, with banding weakening as it traverses further N
as the triple point of occlusion alg with the rvr of highest PWs
slides ENE away from the Rgn via the Can Maritimes. Subsequently,
Rnfl totals thru 00z Fri will be least ovr the far NE where
about a half inch can be xpctd upwards to about 1.50 inches ovr
Downeast and SW ptns of the FA.
About the same can be said regarding winds, which will be
strongest alg the Downeast coast very late tngt thru Thu morn,
where we converted the high wind watch to a high wind wrng.
Further N, a wind adv will be needed for interior Downeast and E
Cntrl ptns of the FA, with a wind adv also for the NE beginning
by mid morn Thu and contg til late aftn. Impact of strong winds
will be exasperated by many trees still holding their leaves,
spcly Downeast adding greater potential of downed trees and
power lines, than if trees where leafless. Rain and winds will
reduce in intensity from SW to NE across the FA durg the aftn
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Low pressure across southern Maine will be occluding and weakening
Thursday night as some scattered showers and drizzle remain over the
region. The low center will continue northeast across New Brunswick
Thursday night. A deep northwesterly gradient both surface and aloft
will allow a gusty northwest wind to follow the low across the area
on Friday. Some showers will linger over the area, mostly Friday
morning. Drier air circulating into the system will taper showers
down by Friday afternoon and bring a clearing trend over the region
Friday night as the low continues away to the northeast and high
pressure begins to build in. The northwesterly breeze will likely
continue Friday night. High pressure building in will bring a return
of sunshine and increasingly tranquil conditions on Saturday.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
High pressure across the area will bring a clear, calm and cool
night Saturday night with fog likely forming in many valleys.
The high will then bring a sunny to partly cloudy and tranquil
day on Sunday. A weak disturbance north of the area may bring
patchy clouds over far northern areas during the day Sunday.
High pressure will remain over the area Monday bringing another
very tranquil day with plenty of sunshine across the entire area
as upper level ridging, supporting strong subsidence, builds in
from the west. This will be followed by a mostly clear night
Monday night. Tuesday will likely begin mostly sunny. Clouds
will then begin to rapidly increase Tuesday afternoon ahead of a
narrow but strong occlusion approaching from the west. As the
occlusion pushes into our area Tuesday night, a strong gradient
between the big high to the east and the lower pressure in the
approaching front will bring a period of potentially strong
southeasterly winds and a band of heavy rain Tuesday night. The
narrow but intense front will continue east into the Maritimes
early Wednesday morning allowing clearing Downeast and partial
clearing across the north with a light westerly wind in its wake
on Wednesday. Dry weather should last into Thursday with a
tranquil night Wednesday night, then an increasing southerly
breeze on Thursday ahead of the next front.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
NEAR TERM: CIGs will continue to thicken and lower late this
afternoon into tonight ahead of the approaching storm system.
Short range guidance is more aggressive with an earlier lower
level cloud deck at BHB and BGR, which corresponds with the
advection of PWAT values well over 1 ahead of the front.
Adjustments were made to show a faster onset of MVFR CIGs at BHB
and BGR compared to model blends.
LLWS will be significant over the lowest 2kft AGL in the
vicinity of the occluded front and heaviest precipitation
Thursday morning. Wind shear and turbulence will also be
possible at higher flight altitudes, particularly in and near
the frontal precipitation band. Winds will turn from SSE to
E/ENE by early Thursday afternoon. The strongest winds will
occur along the coast and near the occluded front Thursday
morning, with peak gusts up to around 45-50 knots. See the rest
of the discussion and hazards for more details regarding the
SHORT TERM: Thursday night: IFR to MVFR. Gusty NW wind.
Friday: MVFR, improving to VFR Downeast. Gusty NW wind.
Friday night: Becoming VFR across the area. Gusty NW breeze.
Saturday: VFR. Light NW breeze.
Saturday night: VFR, locally MVFR or IFR in fog late. Calm air.
Sunday: Locally IFR in any fog early. VFR. Calm air.
NEAR TERM: We went ahead and converted the stm watch to a stm
wrng for all of our coastal marine zones. E winds, which are
currently lgt, will ramp up quickly ovrngt ahead of the
deepening sfc low apchg from the mid Atlc states, likely
reaching stm force gusts prior to daybreak Thu and contg thru
most of the morn ahead of an occluded front. Behind the front by
aftn, winds will shift to the SSW and diminish to gale force.
Initially went with WW3 guidance, then went with 120 percent of
WW3 wv guidance late tngt into Thu, with WW3 tending to underestimate
wv hts ovr outer MZs with fcst strong winds from the S thru E
wind quadrant. Gerling Hanson plots for our outer buoys indicate
short fetch 4 to 6 sec wv pds giving way to storm wvs late tngt
thru Thu with pds of 11 to 14 sec.
SHORT TERM: A gusty NW wind Thursday night through Friday night
may require a SCA. Winds should then diminish Saturday as high
pressure builds in, becoming tranquil Saturday night through
Monday as high pressure crests the area.
Coastal wave heights will rapidly increase overnight from 3 to
4 feet to 10 to 18 feet by Thursday morning, aided by winds
building to Storm force. Rapidly intensifying low pressure, with
an expanding low level wind field, will track into the Gulf of
Maine Thursday afternoon with an increasing fetch to support 10
to 14 sec period swell. Wave and wind direction perpendicular
to the Downeast coast during the high tide cycle, w/sustained
southerly winds 20-30 kts, will increase surge and chances of
minor overwash in prone areas along the Downeast coast. However
the best storm surge potential may be out of phase with the tmg
of high tide erly Thu aftn. A Coastal Flood Statement may be
needed for 1pm high tide Thursday.
ME...Wind Advisory from 8 AM to 4 PM EDT Thursday for MEZ002-005-
Wind Advisory from 4 AM to noon EDT Thursday for MEZ011-
High Wind Warning from 4 AM to noon EDT Thursday for MEZ029-
MARINE...Storm Warning from 4 AM to noon EDT Thursday for ANZ050>052.
Area Forecast Discussion...UPDATED
National Weather Service Hanford CA
339 PM PDT Wed Oct 16 2019
.UPDATE...Updated air quality section.
.SYNOPSIS...A cold front will push southward across the area on
Thursday morning bringing much cooler temperatures and increased
winds as well as a few mountain showers. Another cold front will
push cross the area on Saturday which will result in temperatures
remaining below normal through the weekend. A warming trend is
expected early next week.
.DISCUSSION...IR imagery showing high clouds from some upper
level tropical moisture streaming northeast across central CA
today which has helped mitigate pre-frontal WAA as temperatures
are running fairly close to yday at this time. Meanwhile, an
upper low off the BC coast is pushing a cold front into the PAC
NW today. This cold front is expected to push southward through
Norcal tonight then through central CA on Thursday which will
result in much cooler daytime temperatures across our area. HRRR
indicating increased winds along the ridge tops and below the
passes in Kern County from late Thursday morning through early
Friday morning as onshore p-grads strengthen. As a result, have
issued a Wind Advisory for portions of the Kern County Mountains
and Deserts from 800 am Thursday until 200 am Friday. Gusts up to
55 mph will be possible in these areas. Most of the moisture with
this system is expected to remain to the north of our area, but
isolated showers will be possible over the higher elevations of
the Southern Sierra Nevada on Thursday.
Winds are expected to decrease on Friday, but temperatures will
remain well below normal with a brisk northwest flow aloft
prevailing over our area. WRF indicating another moisture
deficient cold front will push southward through central CA on
Satruday which will bring another shot of cool air to our area
and keep temperatures below seasonal normals through Sunday.
Another impact from this second cold front will be the
possibility of another period of gusty winds over the Kern County
Mountains and Deserts on Saturday.
Medium range models and ensemble means are in fair agreement with
building a dry upper ridge into CA on Monday and Tuesday then
retrograding it slightly offshore on Wednesday. The strengthening
ridge will keep our area dry for much of next week and will
provide for a warming trend early next week with temperatures
rising to near seasonal normals by Monday and above seasonal
normals by Tuesday.
.AVIATION...Areas of MVFR and local mountain obscuring IFR in low
clouds and isolated showers over the Southern Sierra Nevada after
12Z Thu. Otherwise, VFR conditions can be expected over the
central CA interior during the next 24 hours.
.AIR QUALITY ISSUES...None.
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.
Wind Advisory from 8 AM Thursday to 2 AM PDT Friday for
Area Forecast Discussion
National Weather Service Key West FL
951 PM EDT Wed Oct 16 2019
Mostly clear and dry weather prevails across the Florida Keys on
this mid October evening. Radars detect no significant
precipitation across the service area. Temperatures along the
island chain are slowly dropping through the lower 80s, and winds
on land are mostly from the W to NW at 5 mph or less.
Surface analysis depicts a weak high pressure ridge extending from
the central Bahamas through the Straits of Florida and into the
eastern Gulf of Mexico. This high has been pushed southward
during the past 24 hours by a cold front sweeping offshore from
the mid Atlantic and Southeastern states. This front is currently
moving into north Florida, but unfortunately there is no prospect
of it bringing cooler weather to the Keys. Aloft, a deep layered
ridge is centered just south of the Keys over Cuba. The 00Z Key
West, Miami and Nassau soundings all reflect the suppressing
influence of this ridge, with inversions based between 2500 and
6000 feet, dry mid levels, and near normal PW values around 1.65
Overnight, expect mostly clear and dry weather to continue, with
only the slightest chance of a shower due to the low inversion and
suppressing ridge aloft. Isolated showers did develop late
Tuesday night near the Lower and Middle Keys under similar
synoptic conditions, and although most of the CAM guidance
including the operational HRRR does not show any shower activity
near the Keys overnight, will maintain the existing 10 percent
PoPs. Otherwise expect overnight lows to drop to between 75 and 80
degrees, with the clear skies and light to calm winds allowing
minor radiational cooling for sheltered interior island locations
such as North Big Pine Key. The existing forecast is on track, and
no updates are planned for this evening.
No watches, warnings or advisories are currently in effect, and
none are anticipated during the next couple of days. Evening
C-MAN and Weatherflow observations show light mostly W to NW
breezes of 5 knots or less over most of the Keys waters, while
slightly stronger W/SW breezes continue over eastern Florida Bay
and east of the Upper Keys. Expect these winds to die down during
the next few hours, with light flow then prevailing across the
entire area late tonight into Thursday. Winds on Thursday should
be quite similar to those observed today, including the slightly
stronger breezes off the far Upper Keys in the afternoon. No
significant changes are planned for the late evening forecast
VFR conditions will prevail at the EYW and MTH island terminals
overnight and Thursday, with mostly clear skies and little or no
shower activity in the area, as dry and stable mid levels continue
to suppress convection. A shallow cloud line will probably
develop near the island chain again on Thursday afternoon, but
expect little if any impact from this. Surface winds will remain
mostly from the W/NW at less than 5 knots overnight, becoming
light from the SW on Thursday morning.
Positive water level anomalies are running about one foot above
predicted levels at the Key West and Vaca Key tide gauges this
evening. Total water levels during the overnight high tide cycle
should be very similar to those observed on Tuesday night. The
Blackwater Sound gauge also continues to run above predicted
levels. A Coastal Flood Advisory remains in effect for the Middle
and Upper Keys, while a Coastal Flood Statement remains in effect
for the Lower Keys.
FL...Coastal Flood Advisory for FLZ076-077.
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Area Forecast Discussion
National Weather Service Melbourne FL
904 PM EDT Wed Oct 16 2019
Weak frontal boundary across north Florida will push southward
over the area overnight, with west-southwest winds decreasing to
around 5 mph and becoming northwest. Between passing bands of
cirrus and an increase in low level clouds ahead of this boundary,
skies will be partly cloudy with lows dropping into the upper 60s
to lower 70s. Hi-res guidance showing more shower activity than
is actually occurring, and prospects for additional rainfall
overnight with the frontal passage looks minimal so have removed
rain chances from the forecast overnight, except over the offshore
coastal waters where a few showers may still develop.
.AVIATION...Mainly VFR. Low level winds decrease as weak front
moves across the area overnight. Could see some brief MVFR cigs
develop along/ahead of the front, and local WRF hinting at some
fog development as well late tonight. However, MOS and HRRR
guidance not showing any cig/vis reductions at this time, so will
leave it out of the TAFs for now.
.MARINE...Small craft should exercise caution offshore tonight as
westerly winds increasing up to 15-20 knots become northwest as a
weak front moves across the waters. These increasing winds will
build seas up to 5 feet offshore.
.PRELIMINARY POINT TEMPS/POPS...
DAB 67 80 62 77 / 10 10 0 20
MCO 71 85 67 81 / 10 20 10 30
MLB 71 84 69 82 / 10 30 10 30
VRB 70 84 70 84 / 10 30 20 40
LEE 70 85 66 79 / 10 10 10 20
SFB 70 83 66 79 / 10 10 10 20
ORL 71 85 70 80 / 10 10 10 20
FPR 69 84 70 84 / 10 40 20 40
Area Forecast Discussion
National Weather Service San Francisco Bay Area
850 PM PDT Wed Oct 16 2019
.SYNOPSIS...Scattered light rain showers will be possible across
much of the region from later this evening through early Thursday
morning as a weak cold front moves through northern and central
California. Cooler, breezy conditions will develop in the wake of
the frontal passage by Thursday afternoon and will continue into
Saturday. A warming and drying trend is then forecast late in the
weekend and into early next week.
.DISCUSSION...As of 8:50 PM PDT Wednesday...Widespread cloud
cover developed across our region today ahead of an approaching
frontal system. Mostly cloudy skies, along with stronger onshore
flow, resulted in cooler temperatures today. Highs today were
anywhere from 3 to 7 degrees cooler than normal.
Evening satellite and radar data show the incoming frontal
boundary moving through northwest California and extending as far
south as Point Arena. The southern part of the frontal boundary
appears weak and disorganized and recent model trends indicate
less potential for measurable rainfall in our area overnight. The
latest NAM and HRRR models forecast only widely scattered light
rain overnight and it appears most locations will see nothing more
than sprinkles or brief light showers. Rainfall is expected to
end in most areas before the morning commute, although isolated
light showers may continue in the hills of northern Monterey
County until a few hours after sunrise Thursday.
Skies are expected to clear from northwest to southeast on Thursday
morning. Locally gusty west to northwest winds are forecast
behind the front tomorrow, especially in the afternoon. Strongest
winds are expected near the coast and locally in the hills where
gusts up to 35 mph are possible during the late afternoon and
early evening. A cooler airmass moving in behind the front will
keep our temperatures on the cool side of normal. Very little
change is forecast for Friday as cool northwest flow persists.
Locally breezy conditions will continue, but winds on Friday are
not expected to be as strong as tomorrow.
A weather system moving inland to our north late Friday night and
Saturday may produce a brief period of light rain as far south as
the North Bay. The rest of our area is expected to remain dry.
After that system passes inland, an upper ridge is forecast to
build near the West Coast and result in a warming trend from
Sunday into early next week. A brief period of dry offshore winds
are possible late Sunday night into early Monday, but winds then
are not expected to be all that strong.
Longer range models develop a strong upper ridge over California
during the second half of next week, which would result in much
above normal temperatures. The late week warm-up may be preceded
by a brief period of gusty offshore winds in the hills around
Wednesday night which will need to be monitored for potential fire
weather concerns. Otherwise, the warm weather late next week
should occur in conjunction with light winds.
.AVIATION...as of 4:45 PM PDT Tuesday...Based on metars and
webcams low clouds have cleared out even from the coastal areas.
Models in general agreement bringing low level moisture back in at
around 06Z so this is about the time lower cigs should return.
Some light rain within the low cigs getting as far south as the
SFO Bay Area. Winds becoming southwest after 03Z.
Vicinity of KSFO...MVFR cigs after 06Z with bases around 1200-1500
feet. Light rain may accompany the low clouds. West winds 10-15
kt with a gradual turn to the southwest at around 10 kt after
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Low clouds have cleared from the MRY Bay
Area. Models show low level moisture returning by 05-06Z which
should bring IFR cigs to MRY and SNS. Slight chance of showers
early in the morning.
.MARINE...as of 04:28 PM PDT Wednesday...Light northwesterly winds
will persist over the coastal waters this afternoon. Winds will
then briefly turn southerly from north to south late this
afternoon and tonight as a weak cold front moves through the
waters bringing some light rain. Northwest winds will return and
gradually increase behind the front tomorrow. Expect locally
stronger winds along the Big Sur Coast through much of the
weekend. A large northwest swell will arrive tomorrow and build
into Friday. These swells will create hazardous seas over the
waters tomorrow and Friday.
.Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm from 3 AM
SCA...Pt Reyes to Pigeon Pt 0-10 nm from 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 3 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
PUBLIC FORECAST: Dykema
AVIATION: W Pi
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Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
805 PM EDT Wed Oct 16 2019
The round of showers that have been lingering around the region
have now fallen apart. With the frontal boundary draped across
the Florida Panhandle Big Bend region, some instability will be
present overnight. Most notably, the HRRR is very adamant about
developing another round of weak showers in the next few hours
that may make their way onshore around the Tampa Bay region, and
then quickly dissipate. In general, model guidance does support
the development of some showers overnight, but this is expected to
be primarily offshore. Conditions are conducive to support these
weak updrafts, in the event that enough surface convergence can
take place to force the air to rise. With the sun now set, there
is some skepticism as to whether this will actually occur.
Nevertheless, POPs were updated somewhat overnight to account for
the possibility of developing showers. The same trend could
continue into tomorrow, but confidence is still pretty low. As
such, no adjustments have been made after 12Z.
Generally VFR conditions are expected throughout the forecast
period at all terminals. The exception to this is KLAL, where some
low ceilings/fog are included for tomorrow morning. There is also a
possibility for low ceilings tomorrow morning at southern
terminals, most notably KPGD, KFMY, and KRSW, but confidence at
this point remains too low to include in the TAFs. A passing
shower also cannot be ruled out at northern terminals overnight
and during the day tomorrow as weak instability remains over the
area. This could lead to brief MVFR conditions. However,
confidence remains too low at this time to include any TEMPO
groups or VCSH in the forecast at this time.
Some weak showers are possible overnight and during the early
morning hours in coastal waters as a frontal boundary remains over
the region. Winds remain NNW tonight, becoming NNE tomorrow, with
seas of 1-2ft.
.Prev Discussion... /issued 149 PM EDT Wed Oct 16 2019/
Zonal flow remains in place aloft over the region with a low moving
over the Great Lakes region and high pressure to our south. At the
surface, weak high pressure extends over the southern half of the
Florida peninsula with a nearly stationary frontal boundary draped
to our north. This setup is keeping a generally southwest flow in
place across the region. Showers and a few thunderstorms have been
ongoing since this morning, especially across our northern counties,
closer to the frontal boundary, and these will continue to slowly
expand southward but also diminish in coverage as the boundary sinks
southward through tonight.
Thursday will bring a brief shot of cooler and drier air as high
pressure builds over the southeast. These nicer conditions will be
most felt across the Nature Coast region, where some 50s dew points
are forecast. This will be short-lived as an area of low pressure
develops over the central Gulf of Mexico and starts to head toward
Florida on Friday. Flow becomes southeast, with plenty of tropical
moisture spreading over the region. This area of low pressure
currently has a percent chance of becoming a tropical system within
the next 5 days and bears watching. Global models are in general
agreement that this system will make its way toward the region
through the weekend, but the overall evolution still needs to be
refined and these details will obviously play a large part in our
local impacts. For now, those impacts include cloudy and showery
conditions for Saturday and into Sunday. We will also need to keep a
close eye on possible severe weather, mainly Friday night into
Saturday, as well as the possibility of some coastal flooding issues
into the weekend. Still have a couple of days to hopefully nail down
some details, so stay tuned to future forecasts.
High pressure will build back over the area late Sunday or Monday,
although we are not currently forecast to completely dry out. Then
another low pressure system will bring a cold front near the region
toward the middle part of next week.
Will keep VCSH in the forecast for all sites through tonight as a
frontal boundary sinks southward and weakens. Some brief MVFR cigs
will be possible, but otherwise VFR conditions are expected. Light
and variable winds tonight will become generally northwesterly on
A frontal boundary will continue so sink southward across the region
through tonight, with some shower activity possible. Southwest winds
today will become more northwest and then north tonight through
Thursday. A low pressure system will approach the area Friday
through the weekend, with increasing rain chances as well as winds
A frontal boundary will continue to sink southward across the region
through tonight, bringing a few showers to the area. Some drier air
will move into mainly the Nature Coast for Thursday, but relative
humidity values are expected to remain above critical levels. A low
pressure system will approach the area Friday through the weekend,
bringing increased rain chances. No significant fog is expected.
.Preliminary Point Temps/PoPs...
TPA 87 73 85 68 / 60 30 10 0
FMY 88 75 88 73 / 20 10 20 10
GIF 89 72 86 68 / 60 20 20 0
SRQ 88 75 87 71 / 40 30 10 10
BKV 88 69 84 63 / 70 30 10 0
SPG 88 75 85 71 / 60 30 10 10