Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/14/24
Area Forecast Discussion
National Weather Service La Crosse WI
956 PM CST Fri Dec 13 2024
.KEY MESSAGES...
- Wintry mix moves into the region Saturday morning. Freezing
rain, sleet, and snow are all possible precipitation types.
Ice accumulations will be highest over northeast Iowa, up to
0.2 inches, with locally higher amounts to 0.25 inches
possible.
- A Winter Weather Advisory has been issued for much of the
forecast area on Saturday, continuing until midnight Sunday.
- An active pattern is expected next week with multiple chances
for precipitation.
&&
.UPDATE...
Issued at 946 PM CST Fri Dec 13 2024
Forecast largely remains on track for an impactful mix of
freezing rain, sleet, and snow for northeastern Iowa,
southeastern Minnesota, and western Wisconsin. Trends in 13.18z,
early arriving 14.00z, and rapidly updating guidance continue to
point toward a slower arrival time for this wintry weather, with
many locations unlikely to see precip before sunrise Saturday.
Have adjusted the onset of highest PoPs accordingly. That said,
with initial precip favored to be short- lived snow followed by
freezing rain, have kept starting times to the Winter Weather
Advisory the same as there is still a small (20-30%) for precip
arriving with the previous forecast timing.
Along with this trend toward a slightly slower arrival, a
slightly more southern trajectory of the upper low continues to
suggest that Clark/Taylor and Juneau/Adams counties may
struggle to see enough precip for impacts as best forcing fails
to arrive before conditions in the mid-levels begin to dry out.
Have therefore continued to keep these four counties out of the
Winter Weather Advisory. That said, will need to monitor what
occurs closely as 14.00z HRRR continues to suggest a brief
period of freezing drizzle may occur - provided enough low
level lift occurs - as the upper low departs Saturday evening,
including in the aforementioned counties.
&&
.DISCUSSION...
Issued at 142 PM CST Fri Dec 13 2024
Complex Wintry Mix Saturday
The wintry mix scenario expected Saturday continues to be a
complicated mess of several precipitation types stemming from
dry air intrusion, various temperature profiles, and low track
differences. Overall confidence in the specifics of the forecast
(timing, amounts, etc.) remains low, but there is high
confidence that this will be an impactful event.
Ensemble guidance continues in their agreement of the 500hPa
trough/upper low situated over the intermountain west ejecting into
the Great Plains this afternoon, approaching the upper midwest
overnight as an associated surface low pressure system follows suit.
Of note is the slowing trend that continues with the system overall,
adding to the many challenges presented with this event. Continued
to slow onset timing down, with probabilities for precipitation
beginning to increase to the 15-20% range by midnight. Along
with the trouble timing wise from system motion itself, ensemble
forecast soundings have become more adamant that dry air
intrudes the low levels early Saturday morning, with the 13.12z
HREF suggesting dewpoint depressions upwards of 9C in the
900-700hPa layer between midnight and 6am, which slowly
saturates over this time period. This drier air may evaporate
precipitation as it falls, such that there may not be any
precipitation initially overnight before this layer saturates.
However, provided we`re able to punch through this dry layer or
we trend less dry, precipitation may initially be snow as the
event begins before the warm nose nudges into the region where
melting would then lead to the freezing rain/ice pellet threat
Saturday morning and into the afternoon. The 13.12z HREF
continues to indicate northeast Iowa is going to see the highest
ice accumulations, generally up to 0.2 inches, but locally
higher amounts to 0.25 inches are possible.
The surface low tracks south of the area Saturday afternoon
such that the surface warm front will likely struggle to make it
into our area. This would lead to surface temperatures at or
below freezing in the afternoon such that the previously
expected transition to all rain seems less likely at this time
with the HREF suggesting 40-50% rain probabilities with
freezing rain and, to a lesser extent snow, probabilities
making up the rest.
As the low begins to exit to the east, dry air begins to enter the
atmosphere above 700hPa, drying out the DGZ while below 700hPa
remains saturated. This combined with warm air advection at
850hPa and various swaths of frontogenesis sets up a freezing
drizzle scenario across the area Saturday evening into the
overnight hours. Additional impacts would likely occur with this
drizzle Saturday evening.
Active Pattern Next Week
The 13.00z LREF members have come into better agreement
regarding the evolution of the upper level pattern as we head
into next week. One shortwave trough traverses the area Monday
bringing the chance for mainly rain with perhaps some snow
flakes mixed in and another trough traverses the region
Wednesday, bringing chances for snow.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 529 PM CST Fri Dec 13 2024
While VFR conditions are favored to continue for another 12
hours, expect things to deteriorate significantly west to east
as a wintry mix of precipitation, primarily freezing rain and
sleet, moves in. While exact timing is still uncertain,
conditions should reduce to LIFR across the area by the latter
part of the period.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 6 AM Saturday to midnight CST
Saturday night for WIZ032-033-041-053-054-061.
Winter Weather Advisory from 9 AM Saturday to midnight CST
Saturday night for WIZ034-042-055.
MN...Winter Weather Advisory until midnight CST Saturday night for
MNZ086-087-094-095.
Winter Weather Advisory from 3 AM Saturday to midnight CST
Saturday night for MNZ079-088-096.
IA...Winter Weather Advisory until midnight CST Saturday night for
IAZ008>010-018-019-029.
Winter Weather Advisory from 3 AM Saturday to midnight CST
Saturday night for IAZ011-030.
&&
$$
UPDATE...Ferguson
DISCUSSION...Falkinham
AVIATION...Ferguson
Area Forecast Discussion
National Weather Service Dodge City KS
525 PM CST Fri Dec 13 2024
.KEY MESSAGES...
- Fog, freezing fog, drizzle and freezing drizzle are all
possible in central Kansas this evening and tonight, along
with small chances for thunderstorms.
- After tonight, dry weather is expected for the next week.
&&
.DISCUSSION...
Issued at 307 PM CST Fri Dec 13 2024
A robust upper level disturbance will approach the high plains
this evening. Low level moisture was rapidly surging northward
into central Kansas. As mid level cooling arrives by 03z, the
RAP and HRRR indicate cap removal and marginal elevated CAPE,
with isolated thunderstorms between 03 and 07z along and east of
a line from Hays to Kinsley to Coldwater. Most locations will
stray dry even in central Kansas, with chances for storms in the
10-20% range. Low clouds will also expand this evening as the
boundary layer cools. Drizzle can`t be ruled out for a few hours
during the same time frame given the RAP soundings in central
Kansas showing saturation up to about 1 km AGL. Freezing drizzle
is possible along I-70 where temperatures may fall just below
freezing before the drizzle ends. Also, some fog and freezing
fog are possible in central Kansas later tonight after 05-06z
as winds become light northerly.
Sunshine will return Saturday in the wake of tonight`s system.
This will allow temperatures to reach into the 50s across all
of western Kansas. Weak downslope flow is expected Sunday as an
upper level disturbance approaches, allowing temperatures to
reach into the upper 50s to mid 60s from north to south. This
system is fast moving and passing north of Kansas so that rain
chances are near 0%. Another weak front will pass in the wake of
this system, knocking highs back into the 50s for Monday and
Tuesday.
Other fast moving upper level troughs will pass across the
plains Tuesday and again Thursday; but precipitation is not
expected given the lack of moisture. Probabilistically, the
various model ensemble systems indicate 0 to 10% chances for
measurable precipitation. Given the fast moving and mainly zonal
upper level flow with embedded disturbances, arctic air will
stay well to the north until a more amplified pattern develops.
Frontal passages associated with these fast moving fronts will
be weak, with only modest day to day changes in temperature on
the order of 5 to 10 degrees.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 525 PM CST Fri Dec 13 2024
Infrared satellite imagery reveals widespread overcast skies
over southwest KS, but still well within VFR at all terminals.
This will remain the case through this TAF cycle for DDC, GCK,
and LBL, but HYS will see some low stratus move in bringing
MVFR/IFR cigs during the 03-11Z time frame. Otherwise, current
light and variable winds will increase slightly out of the
west-northwest to the 10-12 kt range after 08-10Z, and continue
through 20-22Z before weakening to light and variable once
again.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Finch
AVIATION...Springer
Area Forecast Discussion
National Weather Service Des Moines IA
555 PM CST Fri Dec 13 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Winter/ice storm trending cooler and further south, leading to
prolonged period of freezing rain and/or wintry mix.
- Area- wide ice accumulation of a tenth, with highest amounts
of 0.25" to 0.30" in east central Iowa. Widespread
impacts to travel likely, especially on untreated roads.
- Impacts lingering into Saturday afternoon in the northeast,
with freezing drizzle/mist possible into the evening
throughout the area.
- Milder Sunday and into the beginning of next week.
&&
.DISCUSSION...
Issued at 333 PM CST Fri Dec 13 2024
Onset of the approaching winter storm for this evening has continued
to trend slower and colder, as the location of the low pressure
system trends further south in the guidance. This has been a
consistent trend over the last few days, and has multiple
implications to the expected impacts from the storm.
As the warm air advection wing surges north and east ahead of the
low this evening, lift will be produced by warmer air aloft
overrunning the cold air mass still in place at the surface. A good
amount of moisture will accompany this surge, steadily saturating
the layer through the evening, eventually leading to precipitation.
For much of the area, the presence of a warm nose aloft and/or the
lack of ice introduction should keep the predominant precipitation
type as supercooled liquid as it falls, rather than ice crystals.
Antecedent conditions from recent cold weather will set the stage
for ice accretion as liquid falls. Recent cold weather has grown the
frost depth here at the office from 5 inches on Wedensday to 8
inches today, suggesting very cold ground temperatures. As a result
of these cold ground temperatures, road conditions (which are in the
low to mid 20s north to upper 30s south as of 3 pm today) will cool
off rapidly after sunset and prior to the arrival of precipitation
later this evening. Finally, with the trend in recent high
resolution guidance, temperatures remain below freezing at the
surface for longer through the night and tomorrow morning, with
recent HRRR and RAP guidance not depicting above freezing surface
temperatures in the forecast area until after sunrise tomorrow
morning. This will prolong the amount of time that rain is able to
freeze and accumulate ice on surfaces throughout the area.
All of this has lead to another increase in expected ice amounts
over the area, with widespread values around a tenth, and the
highest amounts of 0.25 to 0.30 inches focused where the greatest
rain amounts are expected in east central Iowa. While forecasted ice
amounts are highest in these areas, research suggests ice
accumulation can over-perform in areas of good saturation,
lift, and wind shear, even with lower QPF. Therefore, while QPF
is lower elsewhere in the state, could still see pockets of
higher ice accumulations closer to that 0.25+ threshold due to
this collision coalescence process.
With this southerly and colder trend in guidance, have expanded the
Ice Storm Warning for tomorrow slightly further south as well. Ice
accretion will make travel hazardous throughout the forecast area
tonight into tomorrow. Breezy winds in areas with higher ice amounts
could lead to tree limb damage, potentially resulting in power
outages due to falling limbs. If you are able to avoid traveling
during this storm, it is highly recommended to do so.
While the freezing rain is the primary headline, other precipitation
types will likely be seen tonight into tomorrow as well, especially
further north. Model soundings indicate there may be a period early
tomorrow morning where deep enough saturation is achieved to
introduce ice into the profile. If the warm nose remains warm and
deep enough, this will still result in mostly freezing rain or ice
pellets as it falls. However, a few model soundings have shown
periods of heavier precipitation rates cooling this warm layer
nearer to 0C. If this were to occur along with the saturation in the
DGZ, could see periods of freezing rain flipping over to snowfall.
With this having a near isothermal layer near freezing, this
suggests a wet, but potentially efficient snow falling, with some
areas picking up a quick half inch to inch of snow or more, mainly
near the IA/MN border. That being said, with the sensitivity to only
a couple degree temperature change, this is far from a consistent
signal, and likely on the more extreme end of possibilities. But,
its worth mentioning, as a transition from freezing rain, to snow,
then back to freezing rain would make for messy conditions.
If the surface layer remains cold and deep enough, could also see
water droplets refreezing and falling as ice pellets/sleet at times.
Should this occur, this would greatly impact both ice accumulation
and/or snowfall amounts in the areas where ice pellets occur. Not
currently expecting this to be the predominant precip type at this
time, but very well could see it mixed in with freezing rain,
especially in the colder air to the north. Needless to say,
precipitation tonight into tomorrow will be fickle, but the signs
point most strongly toward widespread freezing rain, with snow and
sleet being mixed in at times, especially the further north you are.
Finally, warmer temperatures begin to move into southern Iowa
through the day tomorrow, flipping freezing rain over to rainfall in
the south by mid-day. However, areas north of Highway 30 may
struggle to get above freezing, which would keep freezing
precipitation lingering through mid-day until the forcing and
moisture move out in the afternoon. Therefore, while prior messaging
has been for a flip to rain before precipitation ends tomorrow,
recent guidance suggests we may still see frozen precipitation
lasting through much of the day tomorrow, especially northeast. For
this reason, have extended the northeast portions of the winter
weather advisory and ice storm warning into tomorrow afternoon. Even
after headlines end, be on the lookout for freezing drizzle or
mist, as low levels remain saturated into the night.
After tomorrow night, the low levels dry out and temperatures start
to warm up as another approaching trough to the west flips flow to
more southerly. At this point, freezing impacts should begin to wane
as temperatures warm above freezing Sunday morning. Additional rain
chances are possible south and east Sunday night into Monday, with
warmer temperatures through the first part of next week.
Temperatures then cool again mid to late week.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 545 PM CST Fri Dec 13 2024
Notable changes to the TAFs in the short term with an earlier
start time for KFOD and KDSM for FZRA. KFOD may also have PL
mixed in for the initial couple of hours. Have removed LLWS
mentions as a more southward track of the main system has
reduced shear. Have inserted highest confidence for when FZRA
will transition to just RA, which should occur through the
daytime Saturday. High confidence at this time that KMCW will
see FZRA through 00z with some snow potentially mixing in
between 12z and 18z. IFR/LIFR conditions to accompany
precipitation with cigs lowering as the system progresses. Vsby
restrictions also expected to expand through the daytime
Saturday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST Saturday for IAZ004-005-
015-023>025-033>037-044>048-057>060-070>073-081>085-092>097.
Winter Weather Advisory until 6 PM CST Saturday for IAZ006-007-
016-017-026>028.
Ice Storm Warning until 3 PM CST Saturday for IAZ038-039-050.
Ice Storm Warning until noon CST Saturday for IAZ049-061-062-
074-075-086.
&&
$$
DISCUSSION...Dodson
AVIATION...Jimenez
Area Forecast Discussion
National Weather Service Grand Forks ND
947 PM CST Fri Dec 13 2024
.KEY MESSAGES...
- A light glaze of ice with snow accumulations less than one
inch late tonight into Saturday will make for slippery
conditions, mainly along and south of highway 200.
- There is about a 60 percent probability for snowfall amounts
of 2 inches or more Sunday night into Monday, mainly for the
Devils Lake region into northwest Minnesota.
- Gusty northwest winds are expected late Sunday night into
Monday, bringing minor impacts from blowing snow.
&&
.UPDATE...
Issued at 947 PM CST Fri Dec 13 2024
Model soundings still showing favorable profiles for freezing
drizzle as low level moisture starts to move into our southern
counties in the next few hours. However, upstream obs are not
too great, showing more showery snow and pretty big dew point
depressions, with little in the way of the lower ceilings that
would be more favorable for stratiform freezing drizzle. There
is some freezing rain way down in Sioux City, IA, but that area
is much closer to the southern branch low. Still, can`t
completely rule out some freezing drizzle developing, and the
HRRR continues to show some icing in the Red River Valley by
tomorrow. Will keep the advisory going, and will continue to
watch precip as it enters our southern counties.
UPDATE Issued at 632 PM CST
Fri Dec 13 2024
Still very quiet at the moment for our area with high clouds.
Good southerly winds continue, and models start to bring low
level moisture into our southern counties during the 06Z to 12Z
time frame. Still looking like there are decent chances for some
freezing drizzle and possibly light snow. In addition, the HREF
has some 40-70 percent chances for less than a mile visibility
in pockets of far southeastern ND and west central MN. Matched
neighbors and included some patchy fog mention, as moisture
could be fog, BR, or FZDZ. Otherwise no changes to what we have
going.
&&
.DISCUSSION...
Issued at 243 PM CST Fri Dec 13 2024
...Synopsis...
The FA remains between systems today, with the main impact being
gusty south-southeast winds. This may be causing some drifting
snow in open country along with wind chills of 5 below to 15
below. Another closed 500mb low will track from west to east
through the Central Plains tonight into Saturday. The flow ahead
of this system will push some light precipitation well north of
the Central Plains, basically up into at least the southern Red
River Valley into west central Minnesota. After this system
moves through, there is another northern stream shortwave that
tracks from northern California up into the Northern Plains
Sunday night into Monday.
...Mixed precipitation tonight...
Have been watching this potential system for three days now. The
NBM has been downplaying it for the past few days, and it still
doesn`t show much with it. Overall, we are generally expecting
a light glaze of ice with a dusting of snow. This would bring
minor impacts, but will affect Saturday travelers. It is the
holiday season and there are a lot of events going on. Models
have been showing a strong low level jet forming tonight, with a
lot of low level moisture streaming northward. CAMs are much
more robust on the chance of light freezing drizzle tonight
into Saturday morning. The latest HRRR has actually been
trending up slightly in amounts (although still less than 0.10
inches), and shows the area being affected expanding within the
entire RRV all the way to the Canadian border. Feel pretty good
about including southeast North Dakota up through about the
Mahnomen and Bemidji (west central Minnesota) areas for a Winter
Weather Advisory. Later shifts can monitor and adjust as need
be.
...Snowfall Sunday night into Monday...
The next northern stream wave ejects into the Northern Plains
Sunday night into Monday. The previous shift included the
mention of brief mixed precipitation on the leading edge as the
snow spreads in, and that still looks good. Overall, the
probabilities for 2 inches or more of snow have increased to
around 60 percent, mainly across the Devils Lake region,
northern RRV, into northwest Minnesota.
...Blowing snow Sunday night into Monday...
A cold front will pass through the region late Sunday night into
Monday. Therefore gusty south-southeast winds will be replaced
by gusty northwest winds, especially along and west of the RRV.
So along with some falling snow (per the paragraph above), this
wind will only compound the impacts. At this point, the
confidence in minor impacts remains about 30 percent, and mainly
for areas along and north of highway 2, where the higher
snowfall amounts are expected. However, will keep an eye on the
strength of the 850mb cold advection, surface pressure gradient,
etc., over the next few shifts. None of these look particularly
strong at this point, but it is still a few days out and could
change. Iowa State meteograms show a good cluster of sustained
winds around 20 mph, with gusts to 35 mph. If these would go up,
even slightly, impact could increase.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 632 PM CST Fri Dec 13 2024
VFR conditions for the time being with high clouds, but MVFR
stratus and then eventually IFR ceilings will move in later
tonight into tomorrow. At this point think lower visibility
will stay to the south and east of the TAF sites but will
continue to monitor. Some FZDZ and -SN will be possible by the
early morning hours at KFAR and KBJI, with a few lingering
flurries into the later portions of the day. Winds will remain
southeasterly at 10 to 15 kts with some gusts to around 20 kts
at times for some airports.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Weather Advisory until 3 PM CST Saturday for NDZ039-049-
052-053.
MN...Winter Weather Advisory until 3 PM CST Saturday for MNZ002-003-
017-022>024-027>032-040.
&&
$$
UPDATE...JR
DISCUSSION...Godon
AVIATION...JR
Area Forecast Discussion
National Weather Service Goodland KS
853 PM MST Fri Dec 13 2024
.KEY MESSAGES...
- A 10-15% chance of freezing drizzle remains possible across
Norton and Graham counties from 6pm to 11pm CT. A 5% chance
back across Red Willow, Decatur and Sheridan counties for the
same time frame.
- 30% chance of freezing fog developing overnight primarily
along and east of Highway 25. Dense fog may be possible.
- More more mild this weekend with highs in the 50s to 60s along
with currently forecasted dry weather into the start of the
new week.
&&
.UPDATE...
Issued at 737 PM MST Fri Dec 13 2024
Looking at the latest RAP40 500/700/850mb analyses overlaid on mid
level water vapor imagery, the current positioning of the 500/700mb
lows are from the Nebraska panhandle into north central portions of
the state. Current track continues a slow push E/NE through the
evening/overnight hours. There is an 850mb trough ahead of the 500mb
low extending south into western Kansas.
Down to the surface, there is a mix of clear skies and a SCT-BKN mid
level cloud cover associated with the upper systems. There is a
surface low and associated fronts south and east of the CWA. Locales
in the east are on the north side of the low and are seeing a light
northerly flow extending into the Hwy 25 corridor. T/Td spreads are
current 3 degrees or higher and with no low cloud cover currently
impacting anyone, no sign of any freezing drizzle is showing up at
this time. Will continue to monitor this evening as the surface low
lifts further northward w/ the potential to wrap-around more low
level moisture. Current guidance still puts the best potential for
precipitation east of the CWA.
Visibility guidance showing areas along and east of Hwy 83 most
prone to see some fog potential later tonight and may stretch into
the Hwy 25 area, dependent on how much low level moisture wraps into
the area coming up against the drier, colder air to the north.
The latest CAM runs of the HRRR, RAP and NamNest all show some light
precip echoes working into portions of Yuma county around 08z-11z
Saturday. Overall, only some minor tweaks to going forecast at this
time as the area awaits more low cloud to develop in the east for
any fog/precip potential.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 122 PM MST Fri Dec 13 2024
A mid level system is moving across the area which is leading
to the thick cloud cover across the area. As anticipated a lobe
of the cold air mass east of the area has broken off and is
forecast to linger across the area through the day before
progressing to the east overnight as a surface low quickly
develops. Where the clouds will linger through the day
temperatures will struggle to get above freezing with the most
likely areas to remain across east Colorado and southern
counties where a more SSW wind is forecast to develop through
the afternoon.
This evening, there remains a low chance (10-15%) for freezing
drizzle across Norton and Graham counties from around 6pm CT
through 11pm CT. The current mention of the "very light freezing
drizzle" in the forecast seems fairly on point given the weak
isentropic lift in the surface to 1km saturated layer and any
omega (lift) remaining greater than -5 micro bars which is what
is favored for potential freezing drizzle environments. The NAM
continues to be the worst case scenario with a light glaze of
ice across Norton and Graham counties as it keeps the low a
little further west. However based on the current positioning of
the developing mid and surface lows they are a little further
east than the NAM currently and closer to the GFS which keeps
any potential for wintry precipitation out of the area. Overall
given the very weak and marginal signals will forego any winter
weather products at this time. There is also a very low
potential (less than 5%) that freezing drizzle or a wintry mix
can develop a column of counties further west (Red Willow down
through Sheridan). This slight change is from cross sections
suggesting that the dry mid level layer isn`t as deep as what
was being shown yesterday so there may be a period of seeder
feeder processes ongoing with some weak lift in the above
saturated layer which is in the dendritic growth zone. Should
this occur it would be in the 6pm- 8pm CT frame.
Through the remainder night, RAP suggests some additional mid
level moisture on the back end of the developing low may lead to
some flurries or a rogue snow shower across Yuma, Cheyenne
(KS), Sherman, Dundy counties after 1am MT. Given the dry air
that it needs to work through and the weak amount of lift I`m
thinking it will be flurries at best. There is also the
potential for some freezing fog development across the east as
the low begins to depart.The fog formation appears to be from
the collision of a cold air mass from the west and warm air
advection working up from the south. At this time the favored
area for freezing fog looks to be from a Trenton to Monument
Rocks line. Confidence in fog is around 30% and confidence in
dense fog is around 15-20% at this time. Confidence would be
higher in the formation of dense fog if it wasn`t for the winds
becoming more from the NNW which is not climatologically
favored. The fog is forecast to end west to east through around
mid morning as winds become more westerly.
Saturday and Sunday will see more mild temperatures return to
the area as ridging develops across the area leading to sunny
skies and highs in the 50s to potentially 60s on Sunday. Clouds
will then begin to increase again throughout the day on Sunday
as another system approaches as a more progressive pattern
ensues. Sunday night will see a cold front and an associated
850mb jet move across the area with breezy NW winds associated
with due to a 6mb pressure rise over 3 hours. Winds are
currently forecasted to be sustained around 20 mph gusting up to
30 mph. The ECMWF is a little quicker with the jet and has it
moving into northeast Colorado during the afternoon where of
that ends up verifying then some wind gusts up to 35-40 mph may
be possible for Yuma and Dundy counties. As previously mentioned
in the prior discussion there continues to be some hints at a
some mid level moisture Sunday night and into Monday morning but
confidence continues to be to low to introduce anything into
the forecast at this time due to the anticipated drier air at
the surface in wake of the cold front.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 205 PM MST Fri Dec 13 2024
Mon-Wed: An amplified, progressive synoptic pattern with
regular/ periodic waves will prevail over the CONUS early next
week. Long range guidance continues to indicate that the main
belt of mid-latitude westerlies will be relegated to the
northern half of the CONUS (~35-50N).. and that waves therein
will be progressive /fast-moving/ in nature. In such a pattern,
low-level moisture return from the Gulf of Mexico will be
relegated to the Southern Plains and Southern-Central MS River
Valley. In other words, in this pattern.. progressive waves/
troughs are unlikely to be accompanied by precipitation in the
lee of the central Rockies. While day-to-day fluctuations in
wind speed/direction are likely.. temperatures, on the whole,
are anticipated to be near-average.
Thu-Fri: Long range guidance suggests that a less-progressive
/blocked/ synoptic pattern will evolve over North America late
next week into next weekend as a pronounced upper level ridge
amplifies over the Pacific Coast and Intermountain West and deep
troughing /cyclonic flow aloft/ envelopes the remainder of the
CONUS (east of the Rockies) -- a pattern oft-associated with
Arctic outbreaks in the eastern US. In such a setup, the High
Plains would be situated invof an `inflection point` between the
pronounced ridge (to the west) and pronounced trough (to the
east) -- a region characterized by speedy NW-NNW flow aloft and
profound synoptic subsidence -- a region that`s typically on the
far western fringe (or `shore`) of intruding Arctic airmasses.
From a pattern recognition standpoint, one would expect dry
conditions and colder temperatures.. coldest in eastern /low-
elevation/ portions of the Goodland CWA.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 853 PM MST Fri Dec 13 2024
For KGLD, VFR conditions through the forecast period. Winds,
west around 10kts through 20z Saturday, then backing to the
southwest and eventually to the south by 23z. LLWS from 06z-15z
Saturday flight level 010 320@45kts.
For KMCK, MVFR/IFR fog potential from 06z-13z Saturday with a
potential range in visibility from 2-6sm. From 13z onward, VFR.
Winds, mainly light/variable through the forecast w/ a period
from 08z-13z from the NW around 10kts. LLWS from 08z-13z
Saturday flight level 010 320@40kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
UPDATE...JN
SHORT TERM...Trigg
LONG TERM...Vincent
AVIATION...JN
Area Forecast Discussion
National Weather Service Marquette MI
657 PM EST Fri Dec 13 2024
.KEY MESSAGES...
- Temperatures quickly fall back into the single digits above
and below zero after sunset, but then trend warmer into the
weekend. Record warm low temperatures are possible Sunday
night.
- Light lake effect snow possible over the west to northwest
wind snow belts Monday night through Tuesday night.
- Low-end westerly gales over Lake Superior likely (70-90%
chance) late Monday night into Tuesday.
- Stronger lake effect snow possible late this week/next
weekend via another Canadian low.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 312 PM EST Fri Dec 13 2024
The NW LES pattern finally comes to an end through this evening as
high pressure moves over the Great Lakes and mid level ridging
builds in. Current RAP analysis shows the 1040 mb high centered over
Lower MI with a mid level ridge moving into the Midwest. Sfc obs
already are showing a transition to S/SSE flow over the far western
UP and western WI. This increasing anticyclonic flow has resulted in
clearing skies; with increasing WAA, temps have warmed into the
teens to mid 20s this afternoon. The shifting and weakening low
level winds has made the lingering LES become more cellular and
unorganized on satellite and radar imagery. This will continue to
weaken into this evening as the broad mid level trough continues
eastward away from the area, low levels warm up and dry out, and
inversion heights lower. That said, a few spots yet may see up to 2"
of additional dry fluffy snow yet into this evening, but overall
impacts should remain low as the UP mainly turns dry for tonight.
While predominantly dry weather is expected, there are low chances
(15-30%) of light snow showers/flurries tonight over the east and
south-central UP, mainly between 11pm Friday and 4am Saturday EST.
Some upslope flow and marginal lake enhancement may yield a dusting
of snow at best near Lake MI. With high pressure extending overhead
and a period of clear skies over a fresh snowpack, good radiative
cooling is expected. Temps will hit minimums shortly after sunset,
falling into the single digits above and below 0. A warming trend
starts around midnight, continuing into the rest of the weekend.
Otherwise, S to SSE winds continue to increase tonight with gusts in
southerly downslope flow areas approaching 20 mph by Saturday
morning.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 300 PM EST Fri Dec 13 2024
Expect the extended period to start out pretty quiet, with clouds
building in from the southwest Saturday as warm air advection
continues to slowly build in as a shortwave low lifts from the
Central Plains. Depending on how far north the low tracks, we may
see some precipitation associated with it given enough marginal
upper-level diffluence and upsloping from Lake Michigan late
Saturday night into Sunday. Looking at the model temperature
profiles, it seems like a mix of snow, drizzle, and freezing drizzle
is on the table across the area late Saturday night through Sunday,
with a progressive trend towards drizzle throughout the day Sunday
as warm air advection continues. Overall, not much in the way of
accumulations are expected; we could see up to a dusting of snow and
a glaze of ice develop across mainly the central and east Saturday
night/Sunday morning (even over the drizzle areas as the antecedent
cold ground will be frigid enough to freeze the water on contact
initially). While this may cause some slick spots across the
untreated roads, the warmer temperatures later in the day Sunday
will melt this by the afternoon hours. Otherwise, with the lower
levels looking to be saturated, expect fog across much of the Upper
Peninsula Saturday night through Sunday, with the upslope flow off
of Lake Michigan helping to sock-in the central and east.
Expect above normal temperatures to return by early Sunday morning
as the troughing currently over the Pacific Northwest finally pushes
through the Canadian Rockies towards the Upper Great Lakes, allowing
warm air advection to continue to flow in from the Gulf early next
week. Expect high temperatures in the upper 30s to around 40, with
possibly record-breaking warm minimum temperatures on Sunday night
as much of the area is expected to remain above freezing through the
overnight hours (European ensemble showing a 90 to 100% chance of
temperatures above freezing). The very light rain/drizzle and the
patchy fog looks to continue over the U.P. early next week as we
remain in the warm sector of the approaching low. With temperatures
looking to remain above freezing from Sunday through Monday, expect
to see some significant snowmelt across the area. While most spots
in the northwest wind snow belts will still have their snowpack
intact after this warm spell, we could see some bald spots and bare
areas appear over the central U.P. outside of these belts by Monday
evening.
Eventually, the cold front of the low lifts through the U.P. late
Monday through Monday night as showers pick up over the west wind
snow belts. As the winds veer to the northwest with time late Monday
through Tuesday, expect the weak/light lake effect snow showers to
follow likewise. Given that the delta-Ts will be in the low to mid
teens, no significant snowfall accumulations are expected at this
time for this round of lake effect snow. While we can expect a break
from the lake effect snow for a short time during the middle of next
week, expect a low to bring reinforcing cold air back across the
area late this week/next weekend; this brings stronger lake effect
snowfall across the northwest to north wind snow belts to end the
extended period.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 657 PM EST Fri Dec 13 2024
High pressure moving over the forecast area will bring predominantly
VFR conditions for the TAF period. KSAW will see some MVFR ceilings
late tonight into Saturday morning due to lake enhancement off Lake
Michigan as well as southeast upslope flow. Precip is not expected,
but should this overachieve, some flurries may accompany this cloud
deck. There is chance (30%) that ceilings at KSAW will briefly drop
down to IFR during this time. Guidance is hinting (around a 30%
chance)that KCMX could briefly see visiblity drop down to IFR early
Saturday morning. Winds will be light early in the TAF period, with
southeasterly winds with gusts to around 20 kts expected on
Saturday. Cloud cover will start move into the U.P. Saturday
evening, with MVFR ceilings expected to move into KIWD at the very
end of the 00Z TAF period.
&&
.MARINE...
Issued at 300 PM EST Fri Dec 13 2024
Light winds of 20 knots or less this afternoon increase to southerly
winds around 20 knots tonight as a high pressure lifts away from the
Great Lakes region. As a low over the Central Plains continues to
lift towards the Lower Great Lakes this weekend, expect strong warm
air advection to increase the southerly winds to 20 to 30 knots over
the eastern half of the lake by Saturday, before subsiding to 20 to
25 knots over the eastern half by Sunday as the warm air advection
stalls out over the Upper Great Lakes. As a low currently moving
into the Pacific Northwest moves through the Canadian Rockies and
slides through the Canadian Prairies by early next week, expect it
to bring increasing winds from the southwest to west late Monday as
its cold front begins to move across Lake Superior; by late Monday
night to Tuesday, expect westerly gales up to 35 knots across the
open lake (the European ensemble shows a 70 to 90% chance of this
occurring). As the cold air advection and troughing weakens across
the lake Tuesday, expect the winds to weaken during the afternoon to
evening hours, eventually becoming 20 knots or less again by late
Tuesday night. However, another Canadian low looks to drop some more
Arctic air across the lake late next week/next weekend; this cold
air advection could easily bring more strong winds and possibly some
freezing spray concerns with it to end next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Jablonski
LONG TERM...TAP
AVIATION...RM
MARINE...TAP
Area Forecast Discussion
National Weather Service Omaha/Valley NE
526 PM CST Fri Dec 13 2024
.KEY MESSAGES...
- Freezing drizzle or freezing rain developing late this
afternoon and continuing into Saturday morning. Some light
snow could also occur in northeast Nebraska. Untreated roads
will become slippery.
- Ice accumulations will range from a few hundredths of an inch
to upwards of 0.20-0.25 inches, with the highest amounts
expected near or just north of Interstate-80. Snow amounts
should remain less than half an inch.
- Temperatures will trend warmer next week, with highs
predominantly in the 30s and 40s.
&&
.DISCUSSION...
Issued at 210 PM CST Fri Dec 13 2024
Late this afternoon through Saturday...
A deep-layer cyclone --evident in surface observations and water
vapor imagery-- near the WY/CO border as of midday is forecast
to develop southeast, eventually moving through portions of
southeast NE and southwest IA on Saturday. Significant height
falls/forcing for ascent attendant to that system will
overspread the area tonight into Saturday morning when highest
precipitation rates are expected. Prior to that time, 12z
regional soundings indicated a considerable amount of dry air,
generally below 10-15 kft, which will need to be overcome before
robust precipitation processes can occur.
Surface temperatures are creeping into the upper 20s with a few
low 30s observed as of 1 PM, generally along and south of I-80.
However, visible satellite imagery indicates thicker clouds
spreading into southeast NE from KS; a trend that will continue
through the remainder of the afternoon, which will effectively
slow the heating process.
Latest HRRR output suggests the potential for light showery
precipitation to develop by as early as 3 to 4 PM in southeast
NE within a steadily strengthening low-level warm advection
regime. Initial precipitation will likely evaporate owing to a
dry sub-cloud layer. However with time, precipitation will begin
to reach the surface with sub-freezing wetbulb temperatures
(even in areas where the ambient air temperature is 32 or above)
supporting freezing drizzle or light freezing rain.
Continued low-level warm advection and increasing height falls
aloft will allow the precipitation shield to increase in areal
coverage tonight with the predominant precipitation type being
freezing drizzle or freezing rain. The general consensus of the
latest CAM runs indicates a swath of higher simulated
reflectivities and associated higher precipitation rates to the
north of the surface low track beginning about 2-3 AM over
southeast NE, and continuing near and just to the north of I-80
through mid-morning Saturday. Depending on how warm the near-
ground temperature are, this could result in a corridor of
locally higher ice accumulation (0.25-0.35"), a mix of freezing
rain and rain (lower ice accumulations), or just rain. This
forecast update has leaned toward a freezing rain-rain mix. So,
while the storm-total ice accumulations have increased over the
previous forecast (peak values of 0.2-0.24"; similar to the 12z
HREF 75-80th percentile values), they would be too low in the
event that all of the precipitation falls as freezing rain
(i.e., worst case scenario).
Some light snow could mix with the freezing rain tonight over
northeast NE with less than a half inch expected at most
locations through Saturday morning.
Precipitation is expected to move out of the area on Saturday
afternoon with highs ranging from the lower 30s over northeast
NE to lower 40s in far southeast NE.
Sunday through Thursday...
The 12z global models are in reasonably good agreement in
suggesting that another short-wave trough and attending surface
frontal system will progress through the northern and central
Plains Sunday and Sunday night. The best precipitation chances
with that system are expected to remain to the north and south
of our area, and this forecast update will indicate sub-20% PoPs
during that time frame. We will see continued warming on Sunday
ahead of the surface front with highs in the 40s to low 50s.
Even behind the front on Monday and Tuesday, highs are expected
to remain in the 40s owing to the Pacific origins of the air
mass.
There is a model signal that a clipper-type system will move
through the region Tuesday afternoon into Tuesday night with a
short-lived shot of cooler air moving into the area by
Wednesday when highs will top out in the 30s.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 521 PM CST Fri Dec 13 2024
Freezing drizzle and rain are already ongoing in the KOMA and
KLNK vicinity with the expectation that KOFK will shortly join
into the fray, with MVFR ceilings currently in place expected
to turn to IFR and then LIFR over the course of the overnight
hours. Winds have been holding steady out of the east-southeast
and should slowly diminish through sunrise tomorrow. If winds
are able to hold on longer, we could see increased icing at all
three terminals. Latest TAFs have end times added in for
precipitation with the expectation that we start trending
towards better flight conditions (ceiling and visibility-wise)
at the end to just beyond the end of the TAF period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory until 9 AM CST Saturday for NEZ011-012-
015>018-030>034-042>045-050>053-065>068-078-088>093.
IA...Winter Weather Advisory until 9 AM CST Saturday for IAZ043-055-
056-069-079-080-090-091.
&&
$$
DISCUSSION...Mead
AVIATION...Petersen
Area Forecast Discussion National Weather Service Reno NV 307 PM PST
Fri Dec 13 2024
.SYNOPSIS...
* A wetter, warmer, and windier storm with mountain snow and gusty
to strong winds expected for tonight going into tomorrow.
* The heaviest snow rates and strongest winds will be tomorrow
morning, where we will see some spillover into western NV valleys.
* Following a brief respite on Sunday, a much weaker storm will pass
through on Monday bringing additional mountain snow and breezy
winds.
&&
.DISCUSSION...
With the latest RAP analysis showing a low pressure system off the
coast of WA this afternoon, Sierra snow along with gusty to strong
winds are expected tonight and tomorrow. Due to these conditions, a
Winter Storm Warning is in effect for the Sierra Mountain portion of
the CWA that is a bit staggered in its starting points from north to
south. For more specific details in timing and snowfall amounts
along with expected winds, please see the latest Winter Storm
Warning products. When looking at the latest Winter Storm Severity
Index, moderate to major impacts are seen for today and tomorrow in
the Sierra Mountains which means that travel across this area will
be very hazardous (particularly tomorrow morning and afternoon with
increasing snow rates). Please use caution if you must travel
through the area and check out CalTrans and NDOT websites for the
latest road conditions as snow amounts look to be the primary factor
with this storm. Another factor looks to be the blowing snow
potential especially with increased winds expected that will lower
visibilities. When looking at the latest run of the HREF, winds in
the Sierra start to pick up late tonight and peak tomorrow morning.
While not seeing the as much of a snow threat that the Sierra is
expecting, NV counties along the state line will see increased winds
as well. Please see the Wind Advisory and newly issued High Wind
products for more specific details on this as this will cause
hazardous traveling conditions in these areas especially with high
profile vehicles. A Lake Wind Advisory is also in effect for Pyramid
Lake tomorrow with these increased winds. Wintry precipitation
chances do spread east of the CA/NV border this evening into
tomorrow with P-type being mostly rain though there may be some
snowflakes mixed in overnight when snow levels drop. Conditions
expect to start to improve region-wide by tomorrow evening as the
system departs northeastward.
Forecast guidance shows a high pressure ridge moving over the region
on Sunday allowing for dry conditions and cooler daytime
temperatures in the 30s and lower 40s across the region. A much
weaker and drier system looks to move into the area on Monday
bringing back Sierra snowfall chances. When looking at the latest
NBM probabilities, the chances for 3 inches of snow or more with the
Monday system looks to be 30-50% within the Sierra Crest with Donner
Pass seeing the upper portion of this range. Will continue to watch
this in future forecasts as details become more clear in case snow
amounts start to increase. Beyond Monday, an upper air ridge expects
to progress over the region allowing for dry conditions through
Thursday with a very slight warming trend. -078
&&
.AVIATION...
* A stronger winter storm will impact the Sierra today through
Saturday, bringing accumulating snowfall to Sierra terminals, IFR
conditions, mountain obscurations, strong LLWS, and mountain wave
turbulence.
* Expect Sierra terminals to see a total of 5-8" of snow by Saturday
afternoon. Lower terminals like KRNO/KCXP/KMEV are expected to see
just a couple tenths of rain Saturday morning though there may be
some snowflakes mixed in.
* Increased winds will also accompany this system across northeast
California and western Nevada. FL100 winds will peak Saturday 15-
18Z around 60-70 kt out of the S-SW. Terminals in the Sierra and
along the Sierra Front will see strong winds gusting up to 40-45
kt late Saturday morning. -Justin/078
&&
.AVALANCHE...
Today through Saturday`s storm has shifted farther south, overall
increasing precipitation totals and wind potential.
* SWE: Increased notably across the entire Sierra. Greater than 2"
of SWE likely along the Sierra crest from the Tahoe Basin
northward. Greater than 1.5" of SWE likely for the Sierra crest in
Mono County.
* Snow rates: This storm will continue to bring steady snow in the
Sierra through this evening, with rates generally remaining less
than 1"/hr. A heavier band moves into the Sierra generally north
of I-80 around roughly 9-10 pm tonight, invigorating snow rates to
around 1-2" per hour, remaining in place through mid-Saturday
morning. This first band reaches the Sierra in Mono County early
Saturday morning, invigorating rates to 1-2"/hr. Snow rates taper
across Mono County from mid-to-late morning. Another even heavier
band arrives to the northern Sierra mid-Saturday morning,
invigorating rates 2+"/hr through late morning to early afternoon.
2+"/hr rates reach Mono County by late Saturday afternoon. Snow
gradually tapers down to lighter showers across the entire Sierra
early-mid afternoon on Saturday.
* Snow levels: Between 7000-7500 feet across Mono County through
around 10 pm tonight, dropping to 5500-6000 feet early Saturday
morning as the first heavy band arrives. Snow levels to remain
below 6000 feet for the Sierra from the Tahoe Basin northward
through the remainder of this storm.
* Snow amounts: Please see our Winter Storm Warning for more
information.
* Winds: Strong southwesterly winds expected along ridgelines, with
gusts exceeding 120 mph this evening through Saturday afternoon.
Expect a weaker/drier storm Monday, with details to come as we get
closer to this event. -Whitlam
&&
.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 7 PM this evening to 4 AM PST Saturday
NVZ005.
Winter Storm Warning until 10 PM PST Saturday NVZ002.
High Wind Warning from 10 PM this evening to 4 PM PST Saturday
NVZ001.
Wind Advisory from 10 PM this evening to 4 PM PST Saturday
NVZ003.
Lake Wind Advisory from 10 PM this evening to 4 PM PST Saturday
NVZ004.
CA...Wind Advisory from 7 PM this evening to 4 AM PST Saturday CAZ070.
Winter Storm Warning until 10 PM PST Saturday CAZ071-072.
Winter Storm Warning from 1 AM to 10 PM PST Saturday CAZ073.
&&
$$
Area Forecast Discussion
National Weather Service Tallahassee FL
910 PM EST Fri Dec 13 2024
...New UPDATE, MARINE, HYDROLOGY...
.UPDATE...
Issued at 857 PM EST Fri Dec 13 2024
No major changes to the forecast were required. Expect a notably
milder night compared to the previous two thanks to prevailing
easterly flow on the southern periphery of strong high pressure.
Evening regional radar shows light reflectivity returns spilling
westward from near KJAX`s locale. However, Precipitable Water
values are barely 1", so "silent PoP" are maintained invof of
KVLD/KVAX for a very low chance of stray sprinkles. Otherwise, the
only tweak of note was overnight dew points across the northern
tier portions of the Tri-State where northeasterlies advect
mid-30s Td`s.
&&
.NEAR TERM...
(Through Saturday)
Issued at 250 PM EST Fri Dec 13 2024
High pressure remains over the eastern Great Lakes with the
surface ridging nosing into the southeast along the spine of the
Appalachians. Additionally, a mid-level shortwave will skirt
across the area through the overnight hours. In fact, a LLJ
develops overnight with 30 to 40 knot winds in the 925-850 mb
layer. These in tandem will keep winds up, advect warm air into
the region, and bring in some additional cloud cover. This all
will keep our overnight lows from being nearly as cold as the last
couple nights with lows only in the mid-40s to lower 50s.
Additionally, riding on the warm and moist air advecting in, I
can`t completely rule out a couple sprinkles or shallow light
showers moving across south central Georgia overnight. However,
chances for measurable rainfall are very low, and these would
likely only result in a trace at best. Thus, have kept rain
chances less than 10 percent.
With the low-level jet still in place into Saturday morning, it
may become a bit breezy at times with wind gusts of 20-25 mph
possible as the winds mix down. With some wedging along the spine
of the Appalachians, have opted to bring high temperatures
downward a skosh across our northernmost counties. But, it will
still be nice for mid-December with highs in the mid-60s to lower
70s.
&&
.SHORT TERM...
(Saturday night through Sunday night)
Issued at 250 PM EST Fri Dec 13 2024
Another stronger shortwave moves across the Great Lakes and Ohio
Valley into Saturday night, though strong high pressure remains
entrenched across New England. Any appreciable moisture and
consequent rain chances will be confined to the Gulf waters. The
easterly flow piles up against the Appalachians and noses
southeastward again. There is some uncertainty though as to how
far south the cooler air along the Appalachians can get. Have
blended a little bit of MOS guidance to account for the
possibility of a slightly more southward extension of the cooler
air with highs in the mid to upper 60s in AL and GA with 70s in
FL. Lows both Saturday and Sunday nights will be in the lower to
middle 50s.
&&
.LONG TERM...
(Monday through Thursday)
Issued at 250 PM EST Fri Dec 13 2024
Mid-level ridging takes hold during the first part of the long
term, continuing our warming trend with highs climbing well into
the 70s with even pockets of lower 80s in the Big Bend counties
Monday and Tuesday. Ridging breaks down mid-week as a deep trough
plunges into the southeast US Thursday. This will send a cold
front through our area sometime Wednesday night or Thursday.
Moisture return ahead of the front is not significant and only
scattered showers and a couple thunderstorms are expected.
Following behind the front, much colder air will likely filter in
for the latter part of the week.
&&
.AVIATION...
(00Z TAFS)
Issued at 612 PM EST Fri Dec 13 2024
Low level easterly winds will bring in lower cloud decks from the
Atlantic streaming into the tri-state area this period. Cloud deck
should remain VFR through much of the period (035-050) though
decks may approach MVFR at times overnight then an increasing
probability at VLD beginning late in the TAF period. LLJ
increases to AOA 40 knots from the southeast which will lead to
LLWS overnight through mid morning, then mixing down to gusty
surface winds to around 20 knots into the afternoon hours.
&&
.MARINE...
Issued at 857 PM EST Fri Dec 13 2024
From CWF Synopsis...The West Tampa Buoy (42036) was reporting a
sustained ENE wind around 21 kts with gusts in excess of 25 kts,
5-ft waves, and dominant period of 5 seconds this evening. A blend
of the latest HRRR & local CAMs were used on overnight winds,
followed by a manual upward nudge to better reflect the Small
Craft Advisory currently in effect.
Strong high pressure remains in place over the northern
Appalachians, promoting fresh east to northeast winds. A
nocturnal wind surge tonight should help prolong advisory-level
winds overnight into Saturday morning with perhaps another round
Saturday night. As high pressure weakens and the pressure gradient
relaxes, winds and seas should subside late in the weekend into
early next week.
&&
.FIRE WEATHER...
Issued at 250 PM EST Fri Dec 13 2024
Strong easterly transport winds around 15-25 mph on Saturday will
decrease Sunday and Monday to around 10 mph. Mixing heights will
remain around 2-3 kft each afternoon. This will lead to good
dispersions across the area with areas of high dispersions in the
southeast Big Bend. Rain is not expected over the next 3 days.
&&
.HYDROLOGY...
Issued at 857 PM EST Fri Dec 13 2024
The Flood Warning for Pea River at Ariton was cancelled this
evening as the latest observations now show action stage with a
continued downward trend. Releases from Woodruff Dam has now
resulted in the Apalachicola River at Blountstown reaching minor
flood stage. However, this development should be short lived as
the latest forecast gets below 17 ft by 6Z. The FL.W therefore
continues for tonight. No other concerns are expected on area
rivers. Rainfall will wait until mid to late next week, and only
light rainfall is currently anticipated. Thus, no flood concerns
are looming on the horizon.
&&
.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 50 69 55 71 / 0 0 0 0
Panama City 51 71 56 71 / 0 0 10 0
Dothan 47 67 53 67 / 0 0 0 0
Albany 46 66 52 66 / 0 0 0 0
Valdosta 50 69 55 70 / 0 10 0 0
Cross City 51 74 58 76 / 0 0 0 0
Apalachicola 53 69 58 70 / 0 0 10 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Saturday evening for FLZ115.
GA...None.
AL...None.
GM...Small Craft Advisory until 10 AM EST Saturday for GMZ730-765.
Small Craft Advisory until 1 PM EST /noon CST/ Saturday for
GMZ750-752-755-770-772-775.
&&
$$
UPDATE...IG3
NEAR TERM...Young
SHORT TERM...Young
LONG TERM....Young
AVIATION...Scholl
MARINE...Young/IG3
FIRE WEATHER...Young
HYDROLOGY...Young/IG3