Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/17/24
Area Forecast Discussion
National Weather Service La Crosse WI
550 PM CST Mon Dec 16 2024
.KEY MESSAGES...
- Two rounds of accumulating snow are likely on Tuesday and
Thursday this week.
- Confidence is increasing for with measurable snow likely
(50-90%) for much of the area Tuesday and Tuesday night.
Snowfall amounts of 1" or greater will be possible (40-70%)
during this time frame.
- A secondary system moves through the region on Thursday with
accumulating snow. Probabilities for snow accumulations of 1"
or greater are high (60-80%) along and north of I-90 on
Thursday.
- Below normal temperatures are anticipated beginning Wednesday
and into the weekend with high temperatures in the teens and
20s.
&&
.DISCUSSION...
Issued at 250 PM CST Mon Dec 16 2024
Rest of Today - Tuesday Morning:
GOES-16 water vapor imagery and RAP 500mb heights show the general
synoptic pattern this afternoon with a broad troughing/closed low
situated on the border of Manitoba and Ontario. With cloud cover and
continued low-level moisture still in place across the region,
expecting gloomy skies with temperatures maintaining in the middle
30s to lower 40s. Any remaining fog will continue to diminish
throughout the afternoon as ceilings lift slightly with increasing
surface winds.
Tuesday - Wednesday: Cooling Trend and Tuesday Accumulating Snow
This week continues our active pattern with initial zonal flow on
Tuesday behind our frontal passage today keeping temperatures
seasonable with highs generally in the upper 20s and lower 30s.
Could see some attempts at clearing skies with some ever so subtle
ridging aloft working in. However, the next weather troublemaker
that approaches the region is a little shortwave that moves through
the zonal flow east towards the region. It is very dynamic
little wave that becomes more amplified into Tuesday with a
fairly strong 300mb jet streak out ahead of it to around 115-125
kts. Additionally, there remains a fairly consistent 600-800mb
frontogenesis signal in the 16.15z RAP Tuesday evening as this
shortwave moves through. Consequently, expecting a more banded
snowfall event with probabilistic guidance in the 16.12z HREF
showing fairly respectable probabilities for over an inch of
snow within the vicinity of I-90. The overall setup with
frontogenesis forcing present in the dendritic growth zone.
would not rule out some locally higher amounts of 2 to 3 inches
in some spots given the mesoscale nature of this band. Whats
important to note is how narrow this band is so slight shifts in
this band position may have dramatic implications for where the
main axis of snow falls. An additional consideration that some
of the CAMs have picked up on is some low-level forcing in
addition to marginally steeper lapse rates into the overnight
across portions of northeast IA and southwest WI which may aid
in increasing snowfall amounts in this area if this regime
verifies which is not reflected as heavily in probabilistic
guidance. As a result, have keep a wider spread in QPF forecast
for Tuesday evening due to this point of uncertainty.
Regardless, confidence is high that much of the area will see
measurable snow (50-90% chance) in the recent 16.12z HREF with
some areas where these stronger forcing mechanisms are in play
seeing amounts over an inch.
Behind this shortwave. northwesterly flow will usher in sharp cold
air advection knocking our temperatures below normal for Wednesday
with median high temperatures in the 16.00z grand ensemble (GEFS/EC
ensemble/Canadian ensemble) being in the upper teens to around 30
for Wednesday. Overnight low temperatures within the national blend
generally keep in the middle single digits to middle teens.
Thursday - This Weekend: Another Round of Accumulating Snow on
Thursday with Temperatures Remaining Below Normal
Thursday once again becomes very interesting with a shortwave
ejecting out of southern Canada into the northern Great Plains on
Thursday. As it moves southeast towards our region, a surface low
develops at the exit region of this trough and deepens with fairly
strong quasi-geostrophic dynamical lift with it. Still quite a bit
of uncertainty between the global models with different position and
warm sector/cold sector separation. This can be noted in high
temperature spread for Thursday at La Crosse with a 15 degree spread
in the 25th to 75th percentile spread from 21 to 35 degrees. So
really the million dollar question with this system is more
where the axis of snowfall will be rather than confidence on
snowfall occurring which seems highly likely. In light of this,
the probabilities in both the 16.12z GEFS and EC have very high
probabilities (60-100% chance) for over 1 inch north of I-90
and medium probabilities (30-60%) for over 3 inches across
north-central Wisconsin. Consequently, thinking this will be a
more impactful system for the area but still fairly uncertain
where the heaviest snow will fall.
Past this system northwesterly flow remains in place with
reinforcing shots of cold air advection which will keep temperatures
generally below normal into the holiday weekend. Additional pieces
of shortwave energy have been noted amongst the deterministic global
models into the weekend. However, given the larger scale differences
in timing and position with any specific feature, confidence on
precipitation chances remains low after Thursday.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 549 PM CST Mon Dec 16 2024
MVFR ceilings of 2-3kft continue to stream across the area this
evening under northwest flow. KRST may briefly see a scattering
of the OVC deck in the next hour or two based on current
satellite trends, but should quickly return to a ceiling for
the rest of the TAF period. MVFR ceilings continue into Tuesday
for much of the area, but northeast Iowa and far southwest
Wisconsin will likely vary between SCT and BKN/OVC given the
tight moisture gradient laid across this area. West to northwest
gusts of 20-25KT, occasionally up to 30KT, continue overnight,
decreasing Tuesday morning. A band of snow is then expected to
develop across southern Minnesota Tuesday afternoon before
moving across the area. Have added PROB30 groups to the TAFs to
indicated this potential.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...Falkinham
Area Forecast Discussion
National Weather Service Quad Cities IA IL
536 PM CST Mon Dec 16 2024
.KEY MESSAGES...
- Above normal temperatures are expected Tuesday before becoming
more seasonal by mid-week
- A few clipper systems could approach our area by the mid- to
late-week period, but uncertainty on timing and coverage
remains.
- Most impactful clipper will be Thursday that could bring minor
accumulating snow during the AM rush hour across our north.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 327 AM CST Mon Dec 16 2024
We start off the work week with yet another foggy morning for most,
with some dense fog reported for areas along and north of Interstate
80. This morning`s fog forecast remains tricky as the fog seems to
be transient, particularly over our southeastern areas. Latest HREF
ensemble soundings show a very stout low-level thermal inversion for
our northwestern areas which has helped trap moisture near the
surface over the last 24 to 30 hours. Fog potential south of
Interstate 80 appears to be less compared to farther north, but
there remains uncertainty on the impact of a clear slot that has
quickly developed over the last two to three hours or so. The latest
observations have shown visibilities tanking quickly under this
clear slot, which some models have and others don`t. Will
visibilities fall to 1/4 miles under this clear slot? Seems like we
will get close, if not reach that threshold. The latest HREF
exceedance probabilities of quarter mile or less visibility is
around 60 to 90% where we have the going Dense Fog Advisory, so we
will just let it ride, with the exception for Jefferson county in
southeast IA, where confidence is high enough to pull out of the
Dense Fog Advisory. The fog is expected to last through mid-morning
before drier air filters in from the west, slowly eroding it, but
lingering longest over far northeastern Iowa into northwest Illinois.
The remainder of the day looks dry, but breezy, thanks to an
approaching mid-level trough and tightening surface pressure
gradient. West winds look to gust between 20 to 30 mph. The
previously mentioned warm air advection should lead to much warmer
than average temperatures today, with highs warming to the lower 40s
north to the upper 40s south. These temperatures are nearly 10
degrees above average! Dry conditions look to continue tonight, with
lows in the 20s (coldest to the northwest).
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 220 PM CST Mon Dec 16 2024
Little change in the long term forecast as we continue to see an
active pattern with clippers through the period. Overall the
most impactful system is possible Thursday during the AM
commute. Where we could see 1 to 2 inches along the highway 20
corridor. Have included the mid shift discussion below:
For Tuesday night through Friday, the weather pattern will be fairly
active, as we continue to keep an eye on a few clipper systems that
will bring chances of snow to the region. First the Tuesday night
clipper: most of the latest global models depict the compact clipper
to largely miss us to the north as the FGEN band remains farther
north, but the parent trough should help enhance large-scale
forcing, and most model soundings have begun to suggest a saturated
dendritic growth zone concurrent with the trough, so confidence has
increased for a light snow event. NBM exceedance probabilities of a
tenth of an inch of snow shows values now around 30 to 50 percent
over our northeastern forecast area, which is trending higher, but
still not a great signal for accumulating snow. Probably the larger
impact from this clipper will be a drop in temperatures to more
seasonal values, with highs Wednesday back in the upper 20s to lower
30s.
The other, larger clipper system we are keeping an eye on is progged
to approach the region Thursday and Thursday night. Right off the
bat, there remains uncertainty with how this clipper system will
evolve, given spatial differences among the deterministic and
ensemble guidance. However, these differences aren`t as large as
they were 24 hours ago. A broad upper-level trough is progged to
dive southeastward from western Canada, making a beeline towards the
Upper Midwest. Overall, we continue to remain on the southern
periphery of the precipitation shield, but with varying paths for
the surface low among the guidance. Various ensemble guidance
suggests around 30 to 60 percent for measurable snow for areas along
and north of Interstate 80, which has been a relatively big jump
over the last 24 hours. Overall, current indications are
possibly 1 to 2 inches of snow for our far north.
Friday through the upcoming weekend: any remnant snow will cease by
the daylight hours Friday, with a dry weekend ahead. Temperatures
continue to be seasonal, with highs in the 20s to lower 30s, and a
few chilly nights, too.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 531 PM CST Mon Dec 16 2024
00z KDVN upper air flight (in progress) shows a wind speed jump
to 44 knots in the 1-1.5 kft AGL layer. RAP forecast soundings
show this jump but not as high with LLWS becoming marginal
around 06z/17. HREF probabilities show a 40-45% chance of
visibilities under 0.5 miles at KMLI but this was not included
in the 00z TAF due to uncertainty if fog would develop. Wrap
around MVFR CIGS may come close to KDBQ prior to 12z/17 but kept
CIGS VFR for now. Otherwise, expect VFR conditions through
00z/18.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...08
Area Forecast Discussion
National Weather Service Goodland KS
428 PM MST Mon Dec 16 2024
.KEY MESSAGES...
- Breezy to windy conditions Tuesday afternoon in the Tri-Border
area with gusts of 40-50 mph possible.
- Brief cool down Thursday night and Friday morning east of
Highway 25 with a back door cold front.
- Dry through Sunday with generally above normal temperatures.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 115 PM MST Mon Dec 16 2024
The upper pattern will amplify tonight and Tuesday with a ridge
building in the western CONUS and a trough in the Central
Plains. Ahead of the trough, will see increasing mid and high
clouds tonight which may trim a few degrees off morning low
temperatures. They will range from the mid 20s to lower 30s.
Tomorrow, mid and high clouds persist which may again keep
temperatures down just a tad. Still expecting highs in the 50s.
Behind the trough axis there will be a corridor of stronger
winds which will try to mix to the surface, from northeast
Colorado into the Tri-Border area, though with the cloud cover
confidence is medium at best for full mixing potential.
Nonetheless, HRRR showing gusts in the 40-50 mph range in that
area from late morning through mid afternoon. Clouds clear and
winds diminish Tuesday night with lows in the upper teens to
lower 20s. Upper ridge builds across the Rockies and adjacent
plains on Wednesday with dry conditions and highs in the upper
40s to lower 50s. Will see breezy southwest winds by the
afternoon. Lows Wednesday night will be in the upper 20s to
lower 30s. The upper ridge amplifies even further on Thursday
across the western CONUS and adjacent plains. It will be breezy
with northwest winds gusting 20 to 30 mph. Highs will be in the
mid to upper 50s. Relative humidity appears to be too high for
any fire weather concerns. Lows Thursday night will be in the
teens and 20s with a back door cold front bringing in colder air
east of Highway 25. May see some freezing fog with that front
as well.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Issued at 221 PM MST Mon Dec 16 2024
Fri-Sat: Long range guidance continues to indicate that a less-
progressive /blocked/ synoptic pattern will evolve over North
America by the end of the work week as a pronounced upper level
ridge amplifies over the western CONUS and deep troughing
/cyclonic flow aloft/ envelopes the eastern CONUS -- a pattern
often associated with Arctic outbreaks in the eastern US. In
such a setup, the High Plains (geographical area in the
immediate lee of the Rockies) will be situated at an `inflection
point` between the pronounced ridge (to the west) and
pronounced trough (to the east) -- a region characterized by NW
flow aloft and profound synoptic subsidence -- a region that`s
typically on the far western fringe of.. or altogether removed
from.. intruding Arctic airmasses. Bottom line: High confidence
in dry conditions and above average or near average temperatures.
Western portions of the area (i.e. eastern Colorado) are most
likely to see above average temperatures.
Sun-Tue: Long range guidance indicates a dichotomous synoptic
pattern over North America early next week.. in the sense that
(1) a pronounced ridge /block/ will remain in place over
western-central Canada as (2) periodic shortwave energy -- on
the southern and eastern periphery of a large cyclonic
gyre/vortex in the northern Pacific (over the Bering Sea,
Aleutian Islands and Gulf of Alaska) -- moving ashore the
Pacific Northwest erodes, and ultimately supplants, the western
CONUS ridge.. resulting in a more progressive pattern over the
western-central CONUS (beneath the ridge over western-central
Canada). If this is the case, one would expect a relatively
greater potential for active weather over the Central Plains by
mid-week (Xmas Eve-Day). It`s important to note that, a
pronounced and persistent ridge over western-central Canada
would act as a blockade against Arctic airmasses.. resulting in
above normal temperatures and little, if any, potential for
winter weather. Dry conditions and above normal temperatures are
presently anticipated.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 422 PM MST Mon Dec 16 2024
VFR conditions will prevail through the period, but both KGLD
and KMCK will see gusty winds throughout the period. Overnight a
southerly low level jet will strengthen. At KGLD, the winds are
more likely to mix down to the surface and cause some 20 kts
gusts around 6-11Z. KMCK is less likely to mix to the surface,
causing Low Level Wind Shear (LLWS) concerns from 8-13Z. A cold
front will move through in the morning and stronger
northwesterly winds will following the mid-day and afternoon.
Gusts around 25-30 kts are forecast, but gusts up around 40 kts
are possible around 20-23Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...024
LONG TERM...Vincent
AVIATION...CA
Area Forecast Discussion
National Weather Service Houston/Galveston TX
543 PM CST Mon Dec 16 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday Night)
Issued at 257 PM CST Mon Dec 16 2024
Temperatures are warming up into the low 80s early this
afternoon. This is roughly 10 to 20 degrees above normal for this
time of year. Will continue to monitor sites as some of them may
be close to records in the next few hours. As of 2 PM this
afternoon, the City of Houston (IAH) observed a high near 80F,
which is close to its today`s record high of 83F set back in 2021.
With continued onshore flow and decent PWs across the region,
scattered showers with a few lightning strikes will continue to
move inland through early this evening.
Overall, no significant changes were made in the short-term period
as surface low and associated front remains somewhat stalled along
north-central TX. This pattern will continue to bring persistent low
to mid level warm air advection and healthy isentropic lift on the
300K surface. As result, another mild night is expected with low
clouds/stratus and areas of fog, some locally dense. Most Hi-Res
guidance and CAMS suggest high probabilities on low ceilings and
visibility below 1 mile across most of the region overnight. Dense
Fog Advisories will likely be issued later tonight. Areas of fog and
low clouds should gradually dissipate/lift by mid-late Tuesday
morning. Look for another warm day with well above average
temperatures. Isolated to scattered light rain showers and storms
will be possible, mainly in the afternoon.
JM
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 257 PM CST Mon Dec 16 2024
Wednesday is cold front day, but most of us will have to deal with
one more round of unseasonable warmth and mugginess. The general
timing for the front still looks to be in the late morning for the
Brazos Valley, early afternoon for the Houston metro area, and near
the coast or offshore by sunset. Compressional heating ahead of the
frontal boundary will allow for high temperatures to reach the mid
to upper 70s for areas along and south of I-10. Northern areas will
have FROPA before peak heating, so high temperatures there will
mainly be in the low 70s. Just keep in mind that the temperature
forecast is HIGHLY dependent on FROPA timing, so there could be some
further fluctuations as we get in the range of high-res guidance.
The last frames of the 12Z CAMs/18Z HRRR catch the beginnings of
FROPA in Southeast Texas and they depict a line of widely scattered
showers with a few embedded thunderstorms. The potential for
thunderstorms is a bit higher across the Brazos Valley/Piney Woods
along the frontal boundary.
Low temperatures on Wednesday night will be about ~15-20F colder
compared to Tuesday night as we drop into the low to upper 40s. It`s
actually going to FEEL like Christmas is next week, which is a plus
for those that want to get some more wear out of their sweaters. The
forecast going into the weekend is a cool and dry one with high
temperatures mainly in the 60s and low temperatures in the 30s/40s.
A reinforcing front pushes through late Friday and brings even drier
air that prevails into the weekend. Saturday looks to be coldest in
the daytime with high temperatures in the upper 50s to low 60s. High
pressure slides off to the east late in the weekend leading to a
warming trend that takes us into early next week. For an ever so
slight sneak peek into the Christmas forecast, that gradual warming
trend looks to continue into midweek...
Batiste
&&
.AVIATION...
(00Z TAF Issuance)
Issued at 537 PM CST Mon Dec 16 2024
Widespread IFR/LIFR conditions are expected to develop over the
next 3-6 hours, with dense fog and low cigs expected to continue
throughout the overnight period and into the early morning hours.
Dense fog with visibilities of a quarter mile or less is possible
at times, particularly near the immediate coast. BKN/OVC decks
between 200-500ft are expected to accompany the period of fog.
Conditions should improve after sunrise, though MVFR conditions
could prevail into the late morning/early afternoon. Guidance
continues to favor yet another period of fog and low cigs tomorrow
night ahead of a cold front during the day on Wednesday.
Cady
&&
.MARINE...
Issued at 257 PM CST Mon Dec 16 2024
Light southeasterly winds and intermittent periods of sea fog will
persist into the midweek. Water temperatures at buoy 42035 (~20 nm
south of Galveston Bay) and in most of Galveston Bay are currently
around 63F. Dew points will remain in the mid 60s, so the potential
for sea fog (dense at times) continues especially during the
overnight to mid-morning hours. Water temperatures could warm over
the next day or so and make the sea fog more patchy closer to
midweek. A cold front pushes offshore on late Wednesday with
moderate northerly to northeasterly winds and elevated seas
prevailing in its wake, and may necessitate the issuance of caution
flags and/or advisories. Winds and seas gradually diminish on
Thursday, but northeasterly flow will prevail going into the weekend
with a reinforcing cold front pushing offshore late Friday.
Batiste
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 63 77 62 71 / 10 20 10 40
Houston (IAH) 65 76 63 76 / 10 20 0 40
Galveston (GLS) 68 77 65 71 / 10 20 0 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...JM
LONG TERM....Batiste
AVIATION...Cady
MARINE...Batiste
Area Forecast Discussion
National Weather Service Jacksonville FL
925 PM EST Mon Dec 16 2024
...New UPDATE...
.UPDATE...
Issued at 925 PM EST Mon Dec 16 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
A pretty messy pattern with sfc troughing offshore and cool and
moist low level airmass. This is thanks to the persistent onshore
flow and moisture advection. The JAX sounding shows veering in
the low levels which is resulting fairly widespread stratus and
stratocumulus that extends well inland. As for the precip, the
HRRR model is slowly catching up to the numerous showers affecting
parts of Flagler and eastern Putnam. In fact, have added some
isolated t-storms this evening for Flagler county, with recent cloud
tops on IR imagery around -55 to -58C. For the update, the
convective nature of the precip and the persistent cloud cover is,
at least for now, preventing some of the areas to widespread
fog from developing. However, with the forecast calling for the
shower activity over northeast FL to slowly decrease tonight and the
stratus to build down, fog is expected to develop. It is noted that
most of the guidance is not in good agreement with the fog or
the convection. The fog will last into Tuesday morning with slow
improvement. We increased the cloudiness for Tuesday given the moist
low levels which should produce scattered to broken cumulus
through the aftn hours.
For the marine forecast, little change to the wind and sea forecast
and continued to mention fog in the forecast through Tuesday
morning. Some of fog and stratus will linger into the aftn mainly
over the nearshore waters.
&&
.SYNOPSIS...
Issued at 308 PM EST Mon Dec 16 2024
Late afternoon surface analysis depicts gradually weakening high
pressure (1037 millibars) centered over the Canadian Maritime
Region. Meanwhile, coastal troughing situated over our near shore
waters continues to generate scattered showers. Otherwise, a cold
front extends from the western Great Lakes southward through the
southern Plains, with a reinforcing front diving southeastward
from the Canadian Prairies through the northern Plains states.
Aloft...ridging was positioned over the FL peninsula and the
Bahamas, while a trough was progressing eastward from the Upper
Midwest towards the Great Lakes states. A few sprinkles were
occasionally reach coastal St. Johns and Flagler Counties, with
low level onshore flow advecting stratus and stratocumulus clouds
westward across the Suwannee Valley and northward through the
Okefenokee Swamp. Breaks in this cloud cover have allowed
temperatures to climb into the 70s at most inland locations, while
breezy onshore winds and lower stratus ceilings have kept
temperatures in the mid to upper 60s at coastal locations today.
Dewpoints at 20Z ranged from the upper 50s to mid 60s.
&&
.NEAR TERM...
(through Tonight)
Issued at 308 PM EST Mon Dec 16 2024
Coastal troughing will tend to shift slightly northward overnight
as ridging aloft begins to flatten and shift just offshore of the
FL peninsula. Strong surface ridging over the Canadian Maritime
region will also gradually weaken while shifting eastward,
allowing our local pressure gradient to loosen overnight. Dense
sea fog over the near shore waters from St. Augustine northward
will likely move back over coastal locations early this evening,
with this bank of dense fog then migrating inland overnight
through the predawn hours on Tuesday. Coverage of coastal showers
should decrease overnight, but isolated activity may continue
from St. Augustine southward. Developing southwesterly flow aloft
and warm air advection will keep lows in the mid to upper 50s for
southeast GA and the Suwannee Valley, ranging to the low and mid
60s for north central and coastal northeast FL. A loosening
pressure gradient and the low sun angle in mid December may keep
fog and low stratus in place through the mid to late morning hours
on Tuesday at inland locations and possibly through the early
afternoon hours at coastal locations.
&&
.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 308 PM EST Mon Dec 16 2024
Northeasterly onshore flow persists through Tuesday as the coastal
trough remains. The persisting onshore flow will continue to bring
isolated showers along the coast and north central Florida on
Tuesday. There will also be potential for some isolated storms to
develop during the late morning and through the afternoon, as
there may just be enough instability as temperatures rise into
the mid to upper 70s to support some storm development. By the
overnight hours on Tuesday, another night of patchy to areas of
fog will likely develop, spreading in from the coast and south-
southwest towards the inland locations of NE FL and SE GA. The
lingering coastal trough will lift northward as a warm front from
Tuesday night and through Wednesday. This will lead to showers
across more locations than just the coast on Wednesday. With
warmer temperatures on Wednesday, isolated storms during the
afternoon hours can not be ruled out. As a cold front approaches
late Wednesday, showers and storms will begin to dwindle during
the overnight hours heading into Thursday.
The warming trend continues through Tuesday and Wednesday as
daytime highs will reach near or greater than the mid 70s, with
the warmest temperatures along north central Florida with high
into the low 80s. Tuesday night will be the warmest night of the
week with overnight lows in the 60s across the board, warmer
temperatures along the coast and north central Florida counties.
By Wednesday night the approaching cold front will have
temperatures beginning to trend downward once again as lows
mainly in the mid to upper 50s, warmer lows in the lower 60s
along the coast and north central Florida.
&&
.LONG TERM...
(Thursday through next Monday)
Issued at 308 PM EST Mon Dec 16 2024
A cold and dry airmass will settle into the region after the
passage of a cold front during the early hours of Thursday.
Colder temperatures will continue through the end of the week. By
the weekend, another cold front will begin to dig into the region,
bringing another burst of cold air. We may see some of the
coldest temperatures of the season, inland freezes and frost
hazards potential may also make a return for the later half of the
weekend into next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 700 PM EST Mon Dec 16 2024
IFR to LIFR conditions already ongoing for SGJ, CRG, and VQQ and
only a matter of time when JAX, GNV, and SSI deteriorate to IFR
and lower for later tonight. Also, some isolated to scattered
shower activity is overspreading the area as a coastal trough
continues to affect the area. These showers should continue on and
off for a few more hours and then diminish by 06z-12z. Isolated
shower activity again expected Tuesday, probably more scattered
near SGJ Tuesday afternoon. Only slow improvement in cig and vsby
conditions for Tuesday morning, and finally have most of the TAFs
improving to low-end VFR cigs in the 19z-21z time frame. However,
low cigs could linger for the coastal TAFs depending on whether
the trough weakens enough. Mainly thinking that CRG and SSI could
see some low clouds (i.e., IFR) lingering after 20z. Sfc winds
will generally be light from the north- northeast tonight,
increasing only slightly on Tuesday.
&&
.MARINE...
Issued at 308 PM EST Mon Dec 16 2024
Dense sea fog will persist over the near shore waters from St.
Augustine northward, with sea fog then overspreading the waters
south of St. Augustine this evening and persisting into Tuesday
afternoon. Meanwhile, strong high pressure centered over the
Canadian Maritime region will shift eastward while weakening
through tonight, allowing for winds to diminish and seas to
gradually subside later tonight and Tuesday. Small Craft Advisory
conditions will continue throughout our local waters tonight,
with seas subsiding to Caution levels near shore on Tuesday.
A persistent coastal trough situated over our near shore waters
will continue to generate scattered showers through Tuesday night.
Coastal troughing will then sharpen on Tuesday night and
Wednesday as low pressure develops along a frontal boundary over
the Tennessee and Ohio Valleys. Showers and a few thunderstorms
will increase in coverage over our local waters on Wednesday and
Wednesday night well ahead of this approaching frontal boundary.
This front will then cross our local waters early on Thursday,
with winds shifting to northwesterly in the wake of this front
late this week as high pressure gradually builds towards the
southeastern states.
Rip Currents: Elevated surf heights and a long period easterly
ocean swell will keep a high risk of rip currents in place at all
area beaches through Tuesday. Surf heights will diminish by
midweek, but a lingering ocean swell will likely keep a moderate
risk in place at area beaches from Wednesday through Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 56 76 60 76 / 10 10 10 40
SSI 59 70 59 72 / 20 30 20 50
JAX 60 75 60 78 / 20 30 20 50
SGJ 62 74 63 77 / 50 50 30 60
GNV 61 78 62 79 / 20 30 10 50
OCF 62 81 63 81 / 20 40 20 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Tuesday evening for FLZ124-125-133-
138.
GA...High Rip Current Risk through Tuesday evening for GAZ154-166.
AM...Small Craft Advisory until 5 AM EST Tuesday for AMZ450.
Small Craft Advisory until 11 AM EST Tuesday for AMZ452-454.
Small Craft Advisory until 1 AM EST Wednesday for AMZ470.
Small Craft Advisory until 5 AM EST Wednesday for AMZ472-474.
&&
$$
Area Forecast Discussion
National Weather Service New Orleans LA
521 PM CST Mon Dec 16 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday night)
Issued at 230 PM CST Mon Dec 16 2024
Upper ridging currently along the East Coast and over the
Intermountain West. Troughing extended from the western Great
Lakes to near El Paso. At the surface, it was pretty much a repeat
of the upper pattern with high pressure along the East Coast. Low
pressure over western Ontario had a frontal boundary southward
into Missouri, then southwest to west Texas. Under mostly cloudy
skies at mid afternoon, temperatures were in the 70s with dew
points in the mid and upper 60s.
While some brief very light rain showers can`t be entirely ruled
out, most places will likely remain dry. The main concerns over
the next 36 hours will be the potential for advective fog
development. Low clouds appear to be a bit more likely overnight
tonight with GFS and HRRR forecast soundings indicating a moist
layer between 850 and 925 mb potentially producing a low cloud
layer, with somewhat higher fog potential tomorrow night as that
moist layer will be gone. Coordinated with neighboring offices
that a pre-emptive Dense Fog Advisory isn`t currently planned for
overnight tonight, but can`t rule out an eventual issuance by the
evening or midnight shifts.
Would note that current dew points are running several degrees
above guidance, and if those trends continue, with low clouds
holding in, guidance lows are too cool. Have bumped up NBM
deterministic lows for tonight several degrees. Highs for tomorrow
should be pretty close to today`s. With fewer clouds for much of
tomorrow night, did not adjust those lows at this time.
&&
.LONG TERM...
(Wednesday through Sunday night)
Issued at 230 PM CST Mon Dec 16 2024
Strong northern stream shortwave moves across the Lower
Mississippi River Valley Wednesday afternoon and evening. This
system doesn`t have much in the way of moisture coming along with
it, and would be surprised if there`s much more than a few showers
associated with it, and that would primarily be north of the
Interstate 10-12 corridors. Forecast surface wind fields and
forecast soundings would indicate that any significant cold air
advection will not arrive until around sunset Wednesday, or a
little later. This should allow the area to get back into the 70s
on Wednesday for highs.
Once the front clears the area Wednesday night, that ends any
significant precipitation threat for the remainder of the forecast
period. Highs Thursday and Friday will be a good 10-15 degrees
cooler than the first half of the week. A second shortwave early
Friday will reinforce the colder air, so highs Saturday and Sunday
will struggle to get much past 60 degrees. Overnight lows in the
30s and lower 40s are expected Saturday and Sunday mornings, but
widespread freezing temperatures are not expected. Temperatures
are expected to warm back up to above normal levels early next
week heading toward the Christmas holiday.
&&
.AVIATION...
(00Z TAFS)
Issued at 517 PM CST Mon Dec 16 2024
Most terminals are in VFR to MVFR currently but expecting
deterioration to IFR or lower again overnight tonight into
tomorrow morning, primarily due to low ceilings. There is also a
secondary threat for fog but confidence is not as high on whether
a specific terminal will be impacted or not. Conditions should
begin to improve again around 15-16z. -BL
&&
.MARINE...
Issued at 230 PM CST Mon Dec 16 2024
In the near term, will need to monitor the fog threat in the
nearshore waters, but not confident there`s enough of a
temperature difference between the air temperature and water
temperature to promote widespread advective fog. The frontal
passage late Wednesday will likely increase winds to 15-20 knots
with Small Craft Exercise Caution headlines likely to be
necessary. The better chance of Small Craft Advisory conditions is
likely to be with the reinforcing front Friday/Friday night.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 63 74 55 71 / 20 10 0 30
BTR 66 78 58 75 / 10 10 0 20
ASD 61 75 55 75 / 0 0 0 10
MSY 63 74 58 73 / 0 0 0 10
GPT 59 72 55 73 / 0 0 0 10
PQL 56 78 55 78 / 0 0 0 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...RW
LONG TERM....RW
AVIATION...BL
MARINE...RW
Area Forecast Discussion
National Weather Service Marquette MI
524 PM EST Mon Dec 16 2024
.KEY MESSAGES...
- Westerly gales to 35 to 40 knots over Lake Superior are
expected late today into Tuesday morning; some gusts up to 45
knots are possible (25-40% chance) east half. West wind gusts
up to 40 mph are expected in the Keweenaw tonight.
- Light lake enhanced snow is possible over the west to
northwest wind snow belts late today into Tuesday.
- Lake effect snow begins to pick back up again Tuesday night
into Wednesday over the northwest wind snow belts. Snowfall
could become moderate at times Wednesday.
- Eyes are on a weakening Clipper system that could bring some
fluffy snowfall over the U.P. Thursday and Thursday night.
However, we may miss out on the system snowfall entirely
should it go too far south.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 318 PM EST Mon Dec 16 2024
Current RAP analysis on this gloomy and mild day shows the mid level
trough centered along the Manitoba/Ontario province line, extending
south into the Midwest. The sfc low is stacked fairly well below it,
over northwest Ontario at ~998mb. An occluded frontal boundary has
moved over the western UP this afternoon, with a trailing cold front
currently over northern MN expected to move over the UP this evening
into tonight. Ahead of the first frontal boundary, southerly flow
keeps the humid warm air in the upper 30s to low 40s over the east
where some fog remains, some patchy dense fog (below 1 mile vis)
supported by upslope flow still is holding on in Schoolcraft and
Luce counties. As the boundary pushes through, winds shift more
westerly and upslope flow diminishes, so fog should diminish into
this evening. Elsewhere, temps are currently in the mid to upper 30s.
This evening into tonight, the mid level trough pivots over the UP
and the cold front moves through. This results in an uptick in PoPs
over the west this evening and then over the northeast a bit later
tonight as 850 mb temps drop to -6C to -7C behind the cold front.
With Lake Superior sfc temps averaging around 4.8C, this will
support scattered lake enhanced snow showers over the west to
northwest wind snow belts. Also, the destabilization and associated
mixing from CAA will lead to blustery west winds tonight into
Tuesday morning, particularly in the Keweenaw where gusts up to 30-
40 mph are expected; gusts are expected between 20-30 mph elsewhere.
Although some model soundings show the potential for isolated gusts
up to 45 mph in the Keweenaw and 35-40 mph along the Superior
lakeshores, HREF and ECMWF gust probabilities have either remained
the same or diminished 10-20% over much of the CWA. Opted to not
issue a Wind Advisory. Lows settle into the 20s to low 30s.
The pressure gradient slackens on Tuesday as the sfc low continues
to depart and a sfc ridge moves to the south during the day,
resulting in a gradually relax in west to northwest winds. Drier air
working in will also work against the already marginal lake enhanced
snowfall, diminishing coverage and likely providing a dry period for
the west. Some low level convergence and longer fetch over Lake
Superior could bring better, albeit still marginal, snow to areas
along the lakeshores in the east. For the most part, snow totals
through Tuesday should mainly hold below 1". Otherwise, highs will
be colder on Tuesday in the upper 20s to mid 30s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 218 PM EST Mon Dec 16 2024
Lake effect snow looks to pick back up again Tuesday night as
reinforcing cold air advection moves across Lake Superior Tuesday
night into Wednesday. This will allow light to occasionally moderate
snowfall to occur across the northwest wind snow belts by Wednesday
morning, with light snowfall possible across the rest of the U.P.
Wednesday as a weak shortwave low tries to develop across the Great
Lakes region. With winds picking up throughout the day Wednesday, we
could see a return of some patchy blowing snow along Lake Superior
Wednesday into Wednesday evening, mainly in the east near Munising.
Overall, while most of the area will at least see a dusting or some
snowflakes, the northwest snow belts could see 1 to 3 inches of new
fluffy snow, with the highest amounts expected in the east near
Munising.
The main event for the extended period looks to be a Clipper system
dropping southeast towards the Great Lakes Wednesday night to
Thursday. Currently, guidance has the low`s track going as far north
as Central Wisconsin to as far south as the middle of Illinois.
Should the more southerly solutions play out, we shouldn`t see much
of anything save for maybe some light lake effect snow over the
north to northwest snow belts, mainly as we approach Friday as weak
cold air advection moves into the region. However, should the more
northerly solutions be correct, we could see some system snowfall
from the Clipper as well as upslope/lake enhancement ahead of and
behind it too; the largest snow totals look to be over the central
U.P. in the more northerly solutions given the upslope and possible
lake enhancement off of Lake Michigan ahead of the low, and then
upslope flow/lake enhancement off of Lake Superior immediately
behind the low. This will need to be monitored for now in the future
forecast packages, as the more north solutions could have us issuing
winter weather headlines across much of the area. However, with
guidance trending the low further south with time, I`m rather
unsure if this will occur or not.
Behind the Clipper low, some light lake effect snow is expected to
develop behind the it Friday as winds veer more towards the
northwest with time. The light lake effect then looks to become more
northerly early this weekend before ending late this weekend as a
high pressure moves through the Upper Great Lakes. As we head into
early next week, model spread becomes high. However, chances do seem
be to increasing for possible snowfall event come the end of the
extended period into Christmas Day. Regardless, with temperatures
looking to be around to slightly below normal the rest of this week
to Christmas, chances are high (I`m thinking around 70%+) that most,
if not all, of the U.P. will see a `White Christmas` this year given
the possible Clipper snowfall, lake effect snowfall, possible
snowfall event near Christmas Day, and temperatures below freezing
from Tuesday night onwards.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 523 PM EST Mon Dec 16 2024
MVFR/IFR conditions will dominate for this forecast period at all
sites. Some brief periods of IFR/LIFR conditions are possible in
snow showers this evening and tonight as a cold front passes over
the UP. Best chances for showers are at IWD and CMX with some rain
possibly mixing in initially at IWD. Shower coverage diminishes
overnight as ridging builds in from the southwest.
Otherwise, gusty west winds will be a concern at all sites,
especially at CMX where gusts between 30-40 kts are expected
overnight into Tuesday morning. IWD should observe gusts between 20-
30 kts and a bit lower at SAW between 20-25 kts.
&&
.MARINE...
Issued at 218 PM EST Mon Dec 16 2024
Winds are increasing to westerly gales of 35 to 40 knots this
evening into tonight behind a cold front pushing through the lake.
The winds weaken to 20 to 30 knots over the east half by Tuesday
afternoon as the cold air advection behind the front weakens,
eventually becoming 20 knots or less by Tuesday evening across the
entire lake. However, expect the light winds to only last for a
short while, as northwest winds of 20 to 30 knots returns over Lake
Superior by Wednesday as an additional shot of cold air advection
moves over the Upper Great Lakes. Behind this, winds do look to
weaken to 20 knots or less as high pressure moves over northern
Ontario and a Clipper dives towards somewhere between central
Wisconsin and central Illinois. Should this more northerly solution
prove true, we may see some higher winds of 20+ knots back across
Lake Superior Thursday and Thursday night; if not, then we may have
the light winds of 20 knots or less remain through this weekend.
Even if the more northerly solution for the Clipper is true, winds
look to be 20 knots or less by Saturday as high pressure moves
through the Upper Great Lakes behind the Clipper. The light winds
look to continue until possibly next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 10 AM EST /9 AM CST/ Tuesday for LSZ162-
240>242-263.
Gale Warning from 10 PM this evening to 10 AM EST Tuesday for
LSZ243-244-264.
Gale Warning from midnight tonight to 1 PM EST Tuesday for
LSZ245>250-265-266.
Gale Warning from 2 AM to 10 AM EST Tuesday for LSZ251-267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Jablonski
LONG TERM...TAP
AVIATION...07
MARINE...TAP
Area Forecast Discussion
National Weather Service Phoenix AZ
106 PM MST Mon Dec 16 2024
.SYNOPSIS...
Dry conditions and above normal temperatures will persist through
the next 7 days. With high pressure building over the Interior West
during the latter half of the workweek, afternoon highs will near 80
degrees starting Wednesday and into this weekend for some of the
typically warmer lower desert locations such as the Greater Phoenix
Area. These forecast highs are near records for this time of year.
&&
.DISCUSSION...
Current 500 mb RAP analysis shows an upper level trough moving into
the Pacific Northwest, acting to flatten out the weak ridging in
place over the Western US. As a result, heights aloft will be
maintained only slightly above the seasonal average into Tuesday,
and quasi-zonal flow persists over the Desert Southwest. Upper level
moisture wrapping around the base of the trough has led to rather
abundant cirrus over the forecast area so far today. The combination
of zonal flow and cloud cover will act to keep afternoon highs only
5-10 degrees above normal for the date, in the low-to-mid 70s across
the lower deserts today. HREF mean cloud cover depicts much lower
coverage of high level clouds tomorrow, and thus afternoon highs in
the middle 70s look to be more widespread Tuesday compared to today.
A second upper level shortwave is evident in wv imagery further
west of the one currently over the Pacific Northwest, which will
pump up heights aloft downstream along the West Coast starting
Tuesday as it draws nearer. The area of ridging/strong positive
height anomalies will continue to shift east, eventually settling
over the Interior West midweek, and will be a persistent feature
into the weekend.
.PREVIOUS DISCUSSION...
The aforementioned ridge of high pressure will build further on
Wednesday, encompassing much of the Interior Western US allowing 500
mb hghts to climb to around 583-585 dam. This pattern will lead to a
continuation of unseasonably warm temperatures across the region. In
fact, we are expected to see near record highs in Phoenix Wednesday
afternoon with latest NBM probability of setting a new record
currently around 50-60%. By Thursday and Friday, NAEFS mean 850 mb
temperatures are expected to exceed the 90th percentile of
climatology at 16-17C across the forecast area. This would equate to
widespread highs in the mid-to-upper 70s across the lower deserts
with the warmest locations including the Phoenix Metro reaching 80F-
81F. These forecast highs would be 10-15 degrees above average.
Considering record highs are in the upper 70s at Phoenix Sky Harbor,
there is a decent chance (40-70%) of either tying or breaking record
highs in Phoenix from Wednesday through Saturday.
By late next weekend, cluster analysis does indicate that 500 mb
hght anomalies will reduce slightly as a series of weak upper-lvl
disturbances passes through the Intermountain West. Therefore, the
NBM does show high temperatures will gradually cool starting on
Sunday. Although, highs will still remain around 10 degrees above
normal heading into early next week. Along with above normal
temperatures, confidence is high that a dry forecast will continue
for the next several days, likely extending into Christmas week.
&&
.AVIATION...Updated at 1710z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Quiet conditions will prevail across the region under periods of
FEW-SCT high clouds. Overall typical diurnal wind shifts are
expected with periods of very light and variable winds,
especially during the shifts.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns will exist through the forecast
period with FEW-SCT high clouds passing overhead. Light winds out
of the west northwest will prevail through the period.
&&
.FIRE WEATHER...
Dry conditions with well above normal temperatures will transpire
for the next several days. Winds will likely not be an issue this
week, despite some breeziness during the morning hours across the
higher terrain of southcentral AZ. Minimum relative humidity will
fall to around 10-20% each day with overnight recovery remaining
mostly in the poor category. High pressure will continue to build
through the latter half of this week, keeping dry conditions in
place with very little cloud cover anticipated.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Whittock
PREVIOUS DISCUSSION...Salerno
AVIATION...Young/Kuhlman
FIRE WEATHER...Salerno
Area Forecast Discussion
National Weather Service Raleigh NC
923 PM EST Mon Dec 16 2024
.SYNOPSIS...
High pressure and associated cold air damming will extend across the
Piedmont of the Carolinas, while gradually weakening, through
Tuesday. A series of cold fronts will progress across the region
Wednesday night through Saturday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 923 PM Monday...
Dense fog has largely remained west and southeast of central NC this
evening. A few sites across the northern Piedmont have developed
some reduced visibility, but nothing near DFA criteria at this
point. Latest HRRR runs have trended a bit more towards perhaps
keeping the most dense fog mostly out of our area tonight. Best
chances for areas of dense fog would remain across the western
Peidmont and also down in the far southeastern Coastal Plain.
Regardless, patchy fog is possible anywhere tonight. Make sure to
practice fog safety if encountering any fog tonight/early Tuesday
morning.
Previous discussion as of 220 PM:
* Threat for dense fog will be most probable across the southern
Piedmont and Sandhills tonight into early Tuesday morning.
Regional satellite imagery along with 19z surface observations show
the CAD wedge boundary has lifting through the Sandhills and the
central/southern Coastal Plain with pockets of thinning/clearing
forming between the Triad and the Triangle. This boundary will have
a few more hours of poleward mixing before it is stunted by boundary
layer stability from nocturnal cooling. Optical depth satellite
imagery from GOES16 and periodic pilot reports suggest the thickest
cloud layer still remains over the heart of the hybrid CAD regime
across the NC Foothills into portions of the northwest Piedmont.
This suggests INT/GSO will likely remain locked into the low
overcast through the remainder of the daylight hours with gradual re-
thickening and lowering through the overnight period.
A lobe of the CAD surface high analyzed at 15z over the Charlotte
area will settle south over central SC and elongate across the
southern Piedmont and Sandhills through tonight. Calm winds within
the high and residual high boundary layer moisture will be the
favored region for fog, potentially dense. Elsewhere, light
stirring on the northern periphery of the surface high will likely
keep the low overcast that redevelops from reaching the surface and
producing any visibility concerns, although visibility of 1 to 2
miles will certainly be possible. Overnight lows will be mild and
settle in the mid/upper 40s to low 50s.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 240 PM Monday...
Upper level deepening trough moving across CONUS Tuesday and
Wednesday with the axis over the Mid-Atlantic region late Wednesday
night early Thursday. At the surface, a cold front extending from NY
down across the OH and TN valley into the Southern Plains will
continue to slowly shift south and east through the day. While
Tuesday is expected to be mostly dry across the region, calm to
light SW winds in the morning on Tuesday will result in patchy dense
fog across the western Piedmont and portions of the Sandhills
region. Most the of the region will be blanketed with clouds during
the day, except some clearing in the afternoon across the southern
Coastal Plain and portions of the Sandhills could result in
temperatures reaching the low to mid 70s in those areas. Otherwise,
elsewhere temps are only expected to reach the mid/upper 60s. Late
Tuesday night the frontal boundary is expected to move east of the
mountains with increasing rain chances from west to east. Isolated
to scattered showers are expected early Wednesday morning along with
another round of patchy dense fog and low stratus early Wednesday.
The best chance for rain will be in the afternoon and overnight
hours. Latest model data has shown an uptick in thunder potential
across the southeastern portion of the CWA. The potential is low
however, with only 300-500 J/kg of SBCAPE, but cant rule out a
couple of isolated thunderstorms especially in areas across the
south where temperatures are expected to be in the low 70s and dew
points in the mid/upper 60s. SPC does not have our area in any kind
of severe threat for now, but wouldn`t be surprised if they
introduced at least general thunder across our area for late
Wednesday. The front is anticipated to move across the region pre-
sunrise Thursday morning with cool dry air moving in quickly behind
it. Temperatures will promptly drop early Thursday morning after the
front moves through with lows ranging from the low 40s north to low
50s southeast.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 232 PM Monday...
After the front exits the region on Thursday, temperatures will
start to cool, with maximum temperatures in the mid to upper 50s and
lows in the mid to upper 30s Thursday night. Friday, an upper level
trough will pass through the area which will bring a low-end chance
of a few very isolated showers in the Coastal Plain in the
afternoon, however, PoPs are limited due to a lack of moisture and
instability across the area. This system will further cool
temperatures through the weekend as cool high pressure builds in.
Maximum temperatures on Friday will be in the low to upper 50s
before cooling to the 40s on Saturday and cooling further to upper
30s on Sunday. Minimum temperatures follow a similar cooling trend
with temperatures on Thursday night in the 30s, cooling to upper 20s
to low 30s on Friday night, low to mid 20s on Saturday night, and
upper teens to low 20s on Sunday night. Temperatures will begin to
moderate Monday, with highs in the 40s and lows in the low to mid
20s.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 805 PM Monday...
KINT and KGSO: Lingering CAD regime in place at KINT and KGSO will
be especially vulnerable to a period of dense fog and restrictions
at airport minimums tonight and Tuesday morning. There is also
threat for LLWS at these two TAF sites as a 35-40kt LLJ moves
through the region. Conditions will be very slow to improve during
the day on Tuesday, potentially not lifting to VFR until late in the
afternoon(~21z).
At the remaining TAF sites: IFR-LIFR restrictions are expected to
develop across the area between 06 to 12z before lifting to VFR
~15z.
Outlook: Flight restrictions at INT/GSO will likely fluctuate
between IFR-MVFR by day and LIFR-IFR by night through Wednesday
morning, as cold air damming holds over the nw NC Piedmont.
Meanwhile to the east, flight restrictions are likely to be confined
mainly to the late night-morning hours through the same time.
Additionally, showers and possibly a few thunderstorms are expected
to accompany a frontal passage Wednesday afternoon and into
Wednesday night.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...Luchetti/Swiggett
SHORT TERM...CA
LONG TERM...Helock
AVIATION...CBL/MWS
Area Forecast Discussion
National Weather Service Tallahassee FL
919 PM EST Mon Dec 16 2024
...New UPDATE, MARINE...
.UPDATE...
Issued at 911 PM EST Mon Dec 16 2024
The main changes to tonight`s forecast were introducing slight
chance PoP (around 20%) for portions of the Eastern FL Big Bend,
and refining fog placement for the wx grids. For rain chances, the
0Z HRRR develops isolated showers east of Tallahassee that
extend into Apalachee Bay towards sunrise. Evening guidance has
backed off slightly on fog coverage, which now shows the best
potential along/north of the western I-10 corridor after 6Z where
clear skies are currently in place. Locally dense fog of quarter-
mile visibility or less cannot be ruled.
&&
.NEAR TERM...
(Through Tuesday Night)
Issued at 239 PM EST Mon Dec 16 2024
We remain under the influence of high pressure through Tuesday
night, leading to pleasant weather conditions as high temps reach
the mid to upper 70s. Fair weather clouds leading to partly cloudy
skies expected. Overnight conditions remain favorable for patchy to
widespread fog with light to calm winds and clear skies. Overnight
low temps are generally expected to be in the 50s.
&&
.SHORT AND LONG TERM...
(Wednesday through Sunday)
Issued at 239 PM EST Mon Dec 16 2024
A deep trough is expected to move across eastern CONUS Wednesday and
Thursday. However, it`ll be lacking good moisture return with PWATs
struggling to reach 1.25 inches across most of the region. Our
easternmost counties may briefly reaching 1.5 inches and this will
line up with where our best precip chances will be. Otherwise, low
precip chances are expected across most of the region, with around
0.5 inches or less of rainfall expected. Behind the cold front temps
will once again dip as cold and dry cP air bulldozes through the
region this weekend.
Expect overnight temps to be in the 30s post-frontal with daytime
highs being in the 50s post-frontal.
&&
.AVIATION...
(00Z TAFS)
Issued at 641 PM EST Mon Dec 16 2024
The concerns for tonight-tmrw morning are fog/low stratus under
lgt/vrb winds. As of this evening, a borderline MVFR deck is
affecting VLD/TLH while mostly SKC are evident to the west. Fog
aims to develop nearly areawide overnight with the greatest
coverage from 9-13Z. Cannot rule out locally dense fog, especially
at DHN/ABY where this TAF has a tempo for 1/2SM. Amendments may
be needed depending on the evolution. Expect improvements after
14Z, though stratus may linger invof VLD into the aftn.
&&
.MARINE...
Issued at 911 PM EST Mon Dec 16 2024
The West Tampa Buoy (42036) was reporting a sustained NE wind
around 15 kts with 3-ft seas, and a dominant period of 5 seconds
this evening. Isolated showers are possible over parts of
Apalachee Bay early tomorrow morning.
CWF Synopsis...Generally fair boating conditions are expected
through midweek. A cold front moving across the northeast Gulf
waters in the second half of the week looks to elevate winds to
Cautionary conditions, borderline SCA conditions possible.
&&
.FIRE WEATHER...
Issued at 239 PM EST Mon Dec 16 2024
Low dispersions due to light transport winds are expected through
Wednesday. A cold front midweek will bring fair to good
dispersions and minimal rainfall. Temps cool down behind the cold
front.
&&
.HYDROLOGY...
Issued at 239 PM EST Mon Dec 16 2024
Rainfall amounts will generally be around half an inch or less
through the next week. There are no flooding concerns.
&&
.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 57 78 62 76 / 10 20 10 30
Panama City 58 76 60 74 / 0 0 10 20
Dothan 52 75 57 76 / 0 0 0 20
Albany 52 76 58 76 / 0 0 0 20
Valdosta 57 79 62 77 / 10 10 10 40
Cross City 59 80 63 78 / 0 20 10 30
Apalachicola 58 72 61 70 / 10 10 10 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...IG3
NEAR TERM...Oliver
SHORT TERM...Oliver
LONG TERM....Oliver
AVIATION...IG3
MARINE...Oliver/IG3
FIRE WEATHER...Oliver
HYDROLOGY...Oliver