Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/15/23
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
335 PM AKST Tue Nov 14 2023
.SYNOPSIS...
The active weather pattern continues across northern Alaska this
week. The next storm system moves across the Bering Sea tonight
into Wednesday and onshore Thursday, bringing another round of
strong and gusty winds to the West Coast, primarily from the
Bering Strait south. Strong northerly winds could lead to elevated
surf along north facing shorelines. Heavy snowfall expected across
the Western Interior this evening into Thursday, spreading
eastward through Friday. In addition, heavy snow is expected on
the south side of the Alaska Range near Cantwell and south of
Trims Camp. A number of warnings and advisories have been issued.
&&
.DISCUSSION...
Upper Levels and Analysis...
At 500 mb, a 480 dam (decameter) low is anchored over the Laptev
Sea with an upper level trough that encompasses Siberia, the western
Bering Sea, and extends south across the northern half of the
state and into the Yukon. A 507 dam low is over the Western Bering
Sea. Weak ridging extending from the north Pacific to the Seward
Peninsula will slide east northeast across much of mainland Alaska
Wednesday, as the low in the western Bering Sea moves to the
central and eastern Bering Sea and a 491 dam low develops in the
Chukchi Sea. By late Wednesday, the Bering low weakens into an
open wave and is absorbed by the shortwave trough associated with
the Chukchi low. The shortwave will slowly slide eastward to the
Western Interior through Thursday, bringing another round of
southwesterly flow aloft to the Interior.
At the surface, a 984 mb is low 300 NM northwest of Utqiagvik with
a front extending east over the Beaufort Sea and a front extending
south to Utqiagvik and along the northwest Arctic Coast. The low
will weaken to 986 mb as it lifts northeast to be 400 NM northwest
of Utqiaqvik, dragging the fronts with it. A low over the western
Bering Sea this afternoon deepens to 964 mb as it quickly moves
east northeast to be 150 NM northwest of the Pribilofs Wednesday
morning and then weakens to 974 mb as it moves inland to be near
Kaltag Thursday morning. The low weakens to 979 mb as it moves
northeast to be near Indian Mountain Thursday afternoon. As this
low approaches the West Coast and moves onshore, it will push a
series of fronts across northern Alaska. A 980 mb low develops
near Demarcation Point Wednesday night moving north to be 225 NM
northeast of Barter Island by Thursday afternoon.
Models...The 14/12Z model solutions initialized well both at the
surface and aloft and are in good agreement with the overall
synoptic pattern. Differences come into play with the speed and
location of the low moving across northern Alaska. The GFS was
somewhat of an outlier developing a triple point low in Norton
Sound Wednesday morning (though upper level support for it was
iffy), but was not completely discounted as the 12Z HRRR was
showing some support of that solution, while the NAM and ECMWF did
not. Moving into forecast specifics, leaned towards the NAMNEST
for winds, as they were handling the details the best. For pops,
leaned towards the AKSREF. QPF was tricky as there were some large
differences in placement and amount along the West Coast,
southwestern Interior, and over the Alaska Range, where
differences in amounts were up to eight tenths for a six hour
period. Blended GFS, ECMWF, and CONSALL to go for a middle ground
for QPF.
North Slope and Brooks Range...
A lingering front near the northwest Arctic Coast will continue
to enhance snow chances through Wednesday from Utqiagvik west,
droppingup to another 2 inches of snow. Snow becomes more
widespread late Wednesday, as the next system pushes north across
the Brooks Range through Thursday, bringing 2 to 5 inches of snow
to the Brooks Range and Arctic Plains and around 2 inches to
Nuiqsut and Deadhorse. Over the western Arctic Coast, northeast to
north winds of 25 to 40 mph will prevail through Thursday.
Elsewhere, after tonight, winds will largely be less than 15 mph,
with the exception of the passes in the eastern Brooks Range,
where southerly winds of 15 to 25 mph are expected. Temperatures
begin their downward trend Wednesday as an upper level trough
brings in colder air.
West Coast and Western Interior...
With the approach of the next storm system winds take on a
northerly component tonight and increase with winds along the
coast in the 20 to 35 mph range with gusts of 40 to 45 mph. The
exception will be on St Lawrence Island and the Bering Strait
coasts where winds of 30 to 45 mph are expected with gusts of 60
to 65 mph. High Wind Warnings have been issued for these
locations. A mix of precip will accompany this system. Over the
Y-K Delta and into the Yukon Valley and perhaps as far north as
Unalakleet and as far east as McGrath a wintry mix is possible,
with little ice accumulation expected. Elsewhere snow is expected
to be the dominant precip type. Southwesterly flow aloft advects
plenty of moisture into the region allowing for heavy snowfall
across the Western Interior. A wide swath of 7 to 10 inches of
snow is expected from St Mary’s to Ambler east to the Dalton and
south to McGrath, with the highest amounts of up to 16 inches near
Kaltag. Confidence has increased in snow amounts for the Eastern
Norton Sound region and Nulato Hills south to Lower Yukon River.
Expecting 7 to 10 inches of snow, with lesser amounts for
Unalakleet. Winter Storm Warnings have been issued for these
locations. Conditions improve late Thursday as the system moves
east.
Central and Eastern Interior...
The next storm system moves into the region on Wednesday.
Southwest flow pushing moisture into the area will allow for a
swath of heavy snow. Snowfall accumulations of as much as 7 to
inches are expected to fall Wednesday and Thursday west of a line
from the Dalton Highway south to Tanana with a sharp west to east
gradient expected around Tanana. Snowfall amounts will be lighter
east of the Dalton Highway. Winter Storm Warnings for these areas
have been issued. Another area of heavy snow will develop over the
southern side of the Alaska Range near Cantwell and south of
Trims Camp, where 6 to 10 inches of accumulation are expected. The
Fairbanks area and east face a tougher forecast as dry air
associated with a chinook in the Alaska Range pushes over the
area, limiting snow chances. Chinook in the Alaska Range develops
tonight as southerly winds gust to 60 mph in the Alaska Range
passes, peaking midday Wednesday. At the same time, Tanana Valley
Jet winds of 20 to 30 mph with gusts to 45 mph will be blowing
across Delta Junction. At this time, expect winds in Delta
Junction to remain below Wind Advisory criteria. As the Chinook
weakens, a chance of snow returns for the Fairbanks area late
Wednesday and Thursday. High pressure building over the Yukon
southeast of Eagle Tuesday night into Wednesday will result in
southeast winds of 10 to 15 mph developing in Eagle and and being
channeled along the nearby Yukon River. These winds will diminish
Thursday as the high departs.
Extended forecast for days 4 to 7...
The extended period begins with a deepening upper level trough
moving across northern Alaska this weekend. This will bring
cooler temperatures to the region, getting closer to seasonal
norms, although this is only short-lived. As the trough exits,
ridging develops over the Bering Sea and slides eastward to the
mainland Monday. is poised to move in and strengthen across the
state by Monday, opening up the door to warming temperatures and
precip for the West Coast.
Coastal Hazard Potential Days 3 and 4...See High Surf Advisories
for ongoing coastal concerns. Winds will ramp up again out of the
north Wednesday into Thursday over the Bering Strait and Norton
Sound and along the Yukon Delta coast, bringing the potential for
elevated surf along north facing coastlines.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...High Surf Advisory for AKZ802-803.
Winter Storm Warning for AKZ812-831-832-846.
Winter Storm Warning for AKZ819-824-826-828>830-852.
High Surf Advisory for AKZ820-825-827.
High Wind Warning for AKZ821.
High Wind Warning for AKZ827.
Wind Advisory for AKZ847-849.
Winter Weather Advisory for AKZ848-850.
PK...Gale Warning for PKZ801-805.
Small Craft Advisory for PKZ802.
Brisk Wind Advisory for PKZ803.
Small Craft Advisory for PKZ804.
Heavy Freezing Spray Warning for PKZ805-807-810-856.
Heavy Freezing Spray Warning for PKZ806.
Gale Warning for PKZ806-807-856.
Heavy Freezing Spray Warning for PKZ808-855.
Small Craft Advisory for PKZ808-855.
Brisk Wind Advisory for PKZ809.
Small Craft Advisory for PKZ810-811.
Heavy Freezing Spray Warning for PKZ811-812-857>859.
Small Craft Advisory for PKZ812-858.
Brisk Wind Advisory for PKZ813.
Gale Warning for PKZ816-817-850-851-854.
Heavy Freezing Spray Warning for PKZ816-817-851.
Gale Warning for PKZ852.
Gale Warning for PKZ853.
Heavy Freezing Spray Warning for PKZ854.
Small Craft Advisory for PKZ857.
Small Craft Advisory for PKZ859.
Brisk Wind Advisory for PKZ860.
&&
$$
Area Forecast Discussion
National Weather Service Lubbock TX
806 PM CST Tue Nov 14 2023
...New UPDATE...
.UPDATE...
Issued at 753 PM CST Tue Nov 14 2023
Minor update to start the fog mention a few hours earlier tonight
over much of the Caprock. We have also included a dense fog
mention given the HRRR, RAP and NAM showing areas of dense fog
developing near the TX/NM line around midnight, then expanding
over much/all of the Caprock through the early morning hours. This
scenario seems a good bet with mostly clear skies and
temperatures already approaching the dewpoint near the state line,
where Denver City and Hobbs are already reporting minor visibility
reductions (6 and 5 miles, respectively). We could also see
patchy fog, potentially dense, develop further east off the
Caprock toward daybreak, though light downslope winds may
mitigate this potential somewhat. Otherwise, the ongoing forecast
remains on track. We will continue to watch current observations
and trends and issue a Dense Fog Advisory should conditions
warrant later tonight or early Wednesday morning.
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 208 PM CST Tue Nov 14 2023
Stratus continues to erode across the forecast area late this
afternoon with an axis hanging on tough from Plains to Post
northeastward to Plainview and Floydada. Further erosion will occur
with mostly clear skies expected by sunset. However, mixing is not
drying out the surface much, if any, and this prompts concern for
fog and stratus redevelopment later this evening as temperatures
fall, in addition to the threat for advection fog/stratus across the
southwestern quadrant of the forecast area from the stratus that
will be poised not too far into the Permian Basin. Will continue
with a forecast that promotes overcast skies and patchy to areas of
fog during the overnight through Wednesday morning hours. Will leave
out dense fog mention at this time, but that will be something
watched closely as the night progresses. Models seem to be overdoing
the late day and evening surface drying and will tweak tonight`s
lows up a degree or two most areas to account for this. Wednesday`s
highs will be on the tricky side, again predicated on how quickly
stratus clears. Models are likely a bit on the fast side, especially
the GFS, and will trend toward the cooler WRF-NAM and short term
model blends.
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 208 PM CST Tue Nov 14 2023
The models are struggling a bit in the long term portion of the
forecast, specifically with the split flow pattern over North
America mainly from the weekend to early next work week and in
relation to the evolution and progression of an upper level
trough/low progged to replace the low-amplitude ridge that will be
in place over the southern Plains through much of the first third of
the long term period. Significant energy in the southern jet stream
will move across the southern tier of the CONUS during the period,
but it is the energy diving into the western side of this trough
that will have a large bearing on how the main trough develops and
evolves. A significant shift to less of a dominant initial wave on
Saturday as the ECMWF and Canadian were showing to an initially more
progressive movement before significant backside jet energy
amplifies the trough and cuts off a low, although there is far from
agreement on the latter point. The gist of the matter is that
confidence remains low, particularly regarding precipitation
chances. Those chances were already low, and the latest NBM is just
as low, if not lower in a few forecast periods. For now this is the
most reasonable tack to take and will run with no change from the
blend.
Early in the long term periods looks to be fairly quiet, although
Thursday morning could see another round of stratus and fog as the
surface and low levels hang onto moisture. That should begin to
change Friday with a frontal passage late Thursday night, although
some post-frontal stratus cannot be ruled out in the first few hours
behind the southward-moving front. Have made a slight upward
adjustment to the low temperature grids Thursday as models seem to
be underestimating low level moisture, specifically in the surface skin.
&&
.AVIATION...
(00Z TAFS)
Issued at 539 PM CST Tue Nov 14 2023
MVFR ceilings have been stubborn to exit LBB today, though we
could still see a few hours of VFR here later this evening. After
that, low stratus and fog will redevelop, bringing a prolonged
period of LIFR conditions to LBB and PVW from after midnight to
mid-late Wednesday morning. Conditions will gradually improve
thereafter, with a return to VFR early to mid-afternoon. CDS is
more likely to remain VFR this TAF cycle, though there is a chance
of stratus/fog around daybreak Wednesday, despite light downslope
winds.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...07
LONG TERM....07
AVIATION...23
Area Forecast Discussion
National Weather Service Tallahassee FL
858 PM EST Tue Nov 14 2023
...New UPDATE, MARINE...
.UPDATE...
Issued at 856 PM EST Tue Nov 14 2023
No major changes to the forecast were required outside of blending
in tonight`s inland winds with the latest HRRR to account for
current observations and the latest trends. Expect overcast skies
with on and off rain.
&&
.NEAR TERM...
(Through Wednesday)
Issued at 241 PM EST Tue Nov 14 2023
Gulf low will continue moving east toward the CWA over the open
Gulf through the near term bringing much needed wet conditions to
most of the area. Surface high pressure slowly traversing east off
the East Coast will interact with the aforementioned low,
creating a tight pressure gradient over much of the area. Breezy
conditions are expected inland with the highest gusts remaining
confined to the FL Panhandle coast ranging from 30-35kts with some
perhaps as high as 40kts. Thus, a wind advisory is in effect for
the coastal regions of the FL Panhandle. Additionally, strong
winds with large swells will lead to dangerous surf along the
Walton and Franklin county coastlines with waves up to 6ft
possible, prompting the issuance of a high surf warning. These
strong winds out of the ENE will also pose a coastal flooding risk
spanning from coastal Walton county to coastal Jefferson county.
Walton and Bay county may see up to 2 feet of inundation while
coastal Gulf county to coastal Jefferson county may see up to 2.5
feet due to onshore winds over Apalachee Bay. Lastly, a high risk
for rip currents will be in effect all day tomorrow for all of our
beaches. By tomorrow evening, the low will begin to occlude and
take a southeastern track away from the area.
Currently, rainfall totals sit around 1-2" for SW GA, 1.5-2.5" for
SE AL, 1-2" in the FL Big Bend, and 2-3" for the FL Panhandle with
the highest amounts expected along the Emerald Coast to Indian Pass.
With persistent cloud cover and stable conditions inland,
thunderstorms are not expected with this system. The overall flood
threat remains low given the dry conditions lately, though training
storms over urban areas may result in localized nuisance flooding.
Persistent cloud cover this evening will prevent radiational cooling
across the area with temperatures dropping to the low 50s in our SE
AL and northernmost SW GA counties. Our southernmost SW GA and FL
Panhandle counties will drop to the mid to upper 50s with our FL Big
Bend counties dropping to the low 60s. Daytime highs tomorrow will
also be quite cool amidst persistent ENE flow and rainy conditions.
Our SE AL and northernmost SW GA counties will remain in the low 50s
to upper 60s. Our southernmost SW GA and FL Panhandle counties will
reach the upper 60s with our eastern FL Big Bend counties possibly
breaking into the low 70s.
&&
.SHORT TERM...
(Wednesday night through Thursday night)
Issued at 241 PM EST Tue Nov 14 2023
The surface low that occludes Wednesday afternoon will slowly
meander south and east through the period while rain continues to
affect the area along and north of the occluded front in the
northern Gulf of Mexico. With a large pressure gradient remaining
in place, despite a slow weakening of the surface low, winds will
remain high and with this update we extended the gale warning in
place over our marine zones given the potential for windy
conditions to continue into Thursday morning. Wind speeds and
gusts will be much less over inland areas given the widespread
rain and ascent, but still breezy (around 15 to 20 mph) through
much of the night. With the uncertainty in the surface low
position, and strong maritime winds, the threat for coastal
flooding should persist into the the early hours of Thursday with
the high tide cycle. No significant coastal flooding is expected
but with high tide and elevated water levels from this Gulf low,
a minor coastal flooding will remain into early Thursday.
Rain is expected to continue through the period and another batch
of heavier rain can`t be ruled out overnight night Wednesday and
into Thursday, especially along the coastal communities. The main
challenges with the forecast is how far north any embedded storms
along the front lift north. The heaviest rainfall amounts will
likely remain just offshore, but any subtle northward jogs in the
surface low and attendant occluded front Wednesday evening into
Thursday could bring the risk for training storm northwards into
portions of the Panhandle and Forgotten Coast. While this chance
is quite low, its still worth paying attention to overnight as
amounts in this band could bring an additional 3 to 6 inches of
rain in the span of a few hours if it happens. While the area
could mostly support these rainfall totals due to recent drought
conditions, these amounts falling in urban areas or in drainage
poor regions would likely result in localized flooding.
Rain, along with winds, will begin to taper off by Thursday
afternoon and evening as the upper level low continues to fill
and translate east while the surface low continues to weaken. This
will allow low-level winds to begin to decrease leading to seas
slowly improving. With how things have slowed down some in recent
days, we wouldn`t be surprised if rain chances stuck around a
little longer into the evening hours on Thursday.
&&
.LONG TERM...
(Friday through Monday)
Issued at 241 PM EST Tue Nov 14 2023
The upper level trough pulls out of the region and behind it
northwesterly flow will take over. This will bring cooler and
drier conditions to the region and a break from the cloudy and
rainy conditions we saw over the previous week. However, looking
ahead, most guidance is indicating a fairly active and progressive
weather pattern so at some point early next week we`ll likely see
another front and a chance for rain.
&&
.AVIATION...
(00Z TAFS)
Issued at 641 PM EST Tue Nov 14 2023
A mix of VFR/MVFR conds are being observed with lgt rain, overcast
skies, and NE winds 5-10 kts this evening. Meanwhile, the
KTLH/KEVX VWPs show ~45 kts at 2kft, so moved the LLWS line to the
current prevailing group to acct. Remaining sites get impacted by
LLWS beginning overnight/early AM. Main concerns going forward are
gusty winds, low cigs, and bouncing vsbys from RA/-RA. Latest
guidance depicts IFR to LIFR restrictions in the latter part of
this TAF cycle with the earliest onset at ECP/TLH/DHN (6-12Z).
&&
.MARINE...
Issued at 856 PM EST Tue Nov 14 2023
Offshore buoys are reporting sustained east winds around 25 knots
with recent gusts to 35 knots and seas near 10 feet this evening.
The increasing pressure gradient ahead of an approaching Gulf Low
will make for continued and prolonged dangerous boating in the
form of strong sustained easterly winds at or near gale strength
with frequent gusts of 40 knots or greater. Small Craft Advisory
conditions are expected for the waters east of the Ochlockonee
River. Conditions improve by Friday.
&&
.FIRE WEATHER...
Issued at 241 PM EST Tue Nov 14 2023
Fire weather concerns remain low at this time as a wetting
rain is forecast for the majority of the CWA. Dry conditions return
on Friday with pockets of borderline low dispersions.
&&
.HYDROLOGY...
Issued at 301 AM EST Tue Nov 14 2023
Storm total rainfall amounts through Thursday are expected to range
from 1 to 3 inches across the Florida panhandle and western big bend
with localized higher amounts possible near the coast. Across
southeast Alabama, amounts are expected to be mainly between 1 and 2
inches. For southwestern Georgia and the southeast big bend, amounts
mostly between 0.5 and 1.5 inches are expected. Given the recent dry
conditions, this rain will be beneficial overall, and flooding is
not expected to be a big concern. The only potential flooding
concern from rainfall would be urban areas right along the coast if
a heavier convective band sets up over those areas, but confidence
in pinpointing that is low. Latest 12z model guidance still
indicates a non-zero chance of this happening overnight and again
on Wednesday night into Thursday. Amounts in these bands could
range from 3 to 6 inches if they occur, but again confidence in
these bands moving on shore is low and they`re more likely to stay
offshore through this event.
The other concern is for minor coastal flooding along the Wakulla
and Franklin county coasts with persistent strong easterly flow.
With guidance coming up on winds this afternoon somewhat, and the
higher end of the PETSS guidance indicating the potential for
minor flooding, we have issued a coastal flood advisory from
Jefferson county west into Walton county. The highest chances for
minor coastal flooding will likely be the Ochlockonee Bay with
it`s east facing aspect, and if we see these minor inundations
along our coastal communities, it`s likely to occur with the next
few high tide cycles beginning late tonight.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 56 67 61 70 / 90 80 70 50
Panama City 56 68 60 70 / 100 90 80 60
Dothan 51 60 55 67 / 90 90 70 50
Albany 52 61 55 67 / 80 90 70 50
Valdosta 56 66 60 69 / 70 80 60 50
Cross City 61 73 64 74 / 70 50 60 50
Apalachicola 60 69 64 70 / 100 90 80 60
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late Thursday night for FLZ108-112-
114-115.
Wind Advisory until 1 AM EST /midnight CST/ Thursday for FLZ108-
112-114-115.
High Surf Advisory from 1 AM EST /midnight CST/ Wednesday to 1
PM EST /noon CST/ Thursday for FLZ108-115.
Coastal Flood Advisory from 7 AM EST /6 AM CST/ Wednesday to 1
PM EST /noon CST/ Thursday for FLZ108-112-114-115-118-127.
GA...None.
AL...None.
GM...Small Craft Advisory until 1 PM EST Thursday for GMZ730-765.
Gale Warning until 1 PM EST /noon CST/ Thursday for GMZ750-752-
755-770-772-775.
&&
$$
UPDATE...IG3
NEAR TERM...DVD
SHORT TERM...Dobbs
LONG TERM....Dobbs
AVIATION...IG3
MARINE...Dobbs/IG3
FIRE WEATHER...Worster
HYDROLOGY...DVD