Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/01/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
522 PM CST Thu Nov 30 2023
.UPDATE...
Issued at 521 PM CST Thu Nov 30 2023
Current forecast is on track. No major changes are planned.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 150 PM CST Thu Nov 30 2023
KEY MESSAGES:
* Dry weather with mid to high clouds moving in tonight with
temperatures around average
* Low confidence on how cold our temps get overnight due to these
clouds moving in
Mid level flow will switch from a zonal/slight northwest flow to
southwesterly flow later on tonight into Friday as a trough sets up
over the Rockies and a ridge to the north of this as a split flow
pattern continues. This trough will push east Friday into Saturday
with lots of little embedded shortwave pulses on the PVA side of
this longwave trough. No precipitation is expected per ensembles and
deterministic models with this shortwave activity causing moisture
in the form of clouds.
1000-500mb RH per RAP indicates increased moisture moving in from
the west and overtaking most of the CWA Friday. We also have
moisture in the form of clouds coming in from the south and
southeast as a low pressure system pushes east/northeast across the
Southern Plains into the Midwest. HREF cloud cover does agree pretty
well with the Rap which helps increases confidence. At the surface,
a high pressure system will be over the Northern Plains and tracking
east into Friday. This will keep the area dry. HREF tries to show
some lower clouds moving in from the west behind this high as a
surface trough sets up over the Rockies into western SD. HREF/RAP
shows this moisture moving east/northeast and out of the area with
decreasing clouds through the day on Saturday.
This high is bringing CAA as 850mb temps from 06Z-12Z Friday range
from -4 to -7C. How cold we get really depends on these clouds,
which may keep overnight lows a little warmer. We may bottom out
early once we lose the sun as winds will be light, before the
thicker clouds move in, especially the eastern CWA. Thicker clouds
will be over the western CWA little after midnight. Forecasted lows
range from the upper teens to the lower 20s. With CAA still dominant
from the high on Friday, 850mb temps at 00Z Saturday range from -2
to -5C. Average temps are expected although with collab we did bump
them up a few degrees given how the temps the past couple of days
have over preformed from the cooler biased NBM. With the clouds and
poor mixing (southeast winds), temps should not stray too high and
will remain on the cooler side than what we have seen. Forecasted
highs for Friday range in the 30s and lows in the teens and 20s.
.LONG TERM...(Saturday through Thursday)
Issued at 131 PM CST Thu Nov 30 2023
KEY MESSAGES:
- High confidence for above normal temperatures (especially end of
next week) throughout the period.
- Small chances (10-20%) for precipitation Monday/Monday night with
a quick moving system, but low confidence on track and timing.
Still rather mild temperatures showing up at 925/850mb amongst the
deterministic/ensemble guidance through the period, especially by
the middle and end of next week. NAEFS/EC Ens are at or above the
90th percentile for 850mb temps Wednesday into Wednesday evening.
Looking at straight EC/GFS deterministic output for 925mb temps at
00Z Thurs shows readings from +10C to +15C over much of the CWA,
with favorable mixing winds. Inherited NBM temps range from the
upper 40s east, to the low 60s west on Wednesday, but would not be
surprised if these are underdone by several degrees if we end up
having ample sunshine. Looking at the NBM 75th-90th percentiles and
readings are more mid/upper 50s or well into the lower 60s (central
SD), and could easily see some of these temps coming to fruition
given sunshine and good mixing.
As for precipitation, still watching the potential (becoming more
likely) clipper-like low pressure system that moves southeast across
the Northern Plains Monday into Monday night. What`s uncertain
though with this low is the track, which will be key in determining
where the stripe of most likely light QPF will occur. Also, there
seems to be potential for a tight temperature gradient with this
whole system, and track of the low will determine where the warm
sector goes. So, aside from precip chances, highs on Monday bring a
higher uncertainty than normal. The 06Z run of the EC Ensemble 24-hr
probs for measurable QPF ending at 12Z Tues show a large area of 50-
80% across north central into northeast SD and west central MN. The
12Z runs from GEFS/CMC are slightly lower, but still show an area of
50-70% over the northeast CWA. Perhaps this will be the area of most
likely light QPF as the event nears, so will have to watch these
trends in the PoPs. There`s still enough uncertainty and differences
amongst individual ensemble members (some are dry) so that inherited
NBM PoPs are giving only slight (20%) chances at this time.
One other potentially impactful aspect of this clipper system would
be gusty winds on the back side as it moves on through Monday into
Monday night. EC EFI for wind gusts hitting .6 to .7 over the
northwest CWA ending 00Z Tues.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 521 PM CST Thu Nov 30 2023
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are expected through the next 24 hours.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...MMM
LONG TERM...TMT
AVIATION...Wise
Area Forecast Discussion
National Weather Service Des Moines IA
533 PM CST Thu Nov 30 2023
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Thursday/
Issued at 249 PM CST Thu Nov 30 2023
Key Messages:
- Round 1: A wintry mix overnight into Friday morning with
light accumulations mainly along and south of I-80
- Round 2: Light rain and snow Friday afternoon and evening once
again mainly along and south of I-80 with little accumulation
- Round 3: Light rain and snow manly east of I-35 on Saturday night
with little accumulation
Discussion:
We are entering an active period of wintry weather over the next
couple days. While three separate rounds of precipitation are
forecast, each will only result in light accumulation.
Round One: A low is lifting out of the southern plains and into the
central US this afternoon. By this evening the northern side of
the low will approach southern Iowa with precipitation expanding
across southern Iowa overnight. Models are in good agreement with
timing as precipitation arrives after midnight and departs by late
morning. Precipitation type gets a little messier with soundings
indicating variations in ice introduction, surface temperature,
and depth of the warm layer. With much of the lower portion of the
column near freezing, small fluctuations will be impactful for
precipitation type. The NAM remains most aggressive on freezing
rain with coldest surface temperatures. GFS and Euro suites
include better ice introduction, but with surface temperatures
near freezing, it will be a thin line on rain and snow. As this
system fights dry air north, expect that the northern cut off
could be rather sharp from dry to the wintry mix. Better chances
to any ice accumulations would be far south with rain and snow
along and south of the I-80 corridor, trending towards all rain
towards the southeast.
Round Two: As round one exits east midday Friday, a weak embedded
shortwave will follow quickly on its heels bringing another quick
shot at wintry precipitation on Friday late afternoon and evening.
With less available moisture and a little less forcing, QPF with
this round is lighter. With warmer daytime temperatures, this
round is expected as mostly rain, with some snow mixing in
especially into the evening. Primary uncertainty with this round
is timing of the second round, as some of the CAMs maintain
distinct waves while the HRRR has trended towards a more seamless
transition from round one to two. There is also some question as
to snow accumulations. With the column remains deeply saturated
thorugh the DGZ, near surface temperatures hover right at freezing
in soundings from Lamoni to Ottumwa. Given good saturation to the
surface, expect little wetbulb influence to cool the column and
push things one way or the other.
Round Three: After a lull, the parent trough axis passes across the
area Saturday evening and overnight. Precipitation here reaches
further north, but recent model runs have pulled the system
further east with main QPF along and east of the I-35 corridor.
The primary precipitation type here will be rain, however some
light snow may mix in overnight Saturday as the column cools and
ice introduction increases. Any accumulations with this final
round would be very light, a dusting or so.
Into next week a quick moving shortwave swings across the area on
Tuesday, delivering another shot at at wintry precipitation. This
will be followed by a warming trend to finish out the week with
above average temperatures.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 531 PM CST Thu Nov 30 2023
Conditions will deteriorate across southern Iowa overnight and
into Tuesday and will impact KOTM with lowering cigs and
increasing chances for rain and snow. Conditions are expected to
reach IFR or lower at times. KDSM likely will have cigs lower to
MVFR for a period on Friday and those conditions could briefly
reach KALO. Otherwise VFR at KFOD/KMCW for the period. Northern
wind will become northeasterly overnight. The wind may become
breezy to gusty at times Friday, especially in the vicinity of
KOTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to noon CST Friday
for IAZ062-073>075-082>086-092>097.
&&
$$
DISCUSSION...Hagenhoff
AVIATION...Donavon
Area Forecast Discussion
National Weather Service Grand Forks ND
709 PM CST Thu Nov 30 2023
.UPDATE...
Issued at 703 PM CST Thu Nov 30 2023
Stratus continues working southward into the region this evening,
with near overcast skies from Highway 200 and points north.
Isolated flurries remain possible, primarily along and just south
of the International Border in northwest Minnesota. Given the
thicker cloud cover, temperatures are holding steady in the 20s
for many areas north of Highway 200, with temps falling into the
teens to low 20s across the I-94 corridor in eastern North Dakota.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 232 PM CST Thu Nov 30 2023
Key Message:
- Chance for a few flurries in northwestern MN this evening,
otherwise quiet and dry through the end of the work week.
West to northwesterly flow aloft continues across the region, with
one weak shortwave from this morning exiting through the MN
arrowhead and another subtle shortwave digging through southern
Saskatchewan. This weak shortwave will head off into southwestern
Ontario tonight. Plenty of cloud cover upstream, with at least the
northern counties staying socked in overnight. Around a 20 percent
chance for clouds lower than 3000 ft by the early morning hours.
The HRRR brings some very light precip into portions of
northwestern MN this evening. Think chances for anything
measurable are very low, but could see a few brief flurries along
the international border as the shortwave moves through. Included
a mention but no impacts are expected.
Flow becomes west to southwesterly tomorrow as the next upper
trough digs into the Rockies. Weak surface high pressure moves to
the east and winds return to the south to southeast. Clouds in the
north should be decreasing a bit by daytime tomorrow but more
clouds coming in across the south with waves going through the
Central Plains. Temps will be on the warmer side of average in the
upper 20s to mid 30s, and lows Friday night around 20 degrees.
.LONG TERM...(Saturday through Thursday)
Issued at 232 PM CST Thu Nov 30 2023
Ahead of an upper wave arriving in the northern plains late this
weekend dry westerly upper level flow will switch to
southwesterly. As a sfc low develops to our south increasing cloud
cover with help to limit highs this weekend to the low to mid 30s
which is still near to slightly above average. With the expected
track of the sfc low we are not anticipating any precip across the
area. As the upper low and attendant sfc low track east by monday
flow begins to turn more northwest/northerly ahead of building
western ridging. However this northwest flow is expected to be
relatively short lived as the the ridge flattens allowing more
zonal flow latter in the week. It is in the in between period of
Late Monday into Wednesday that ensemble guidance continues to
show chances for precip across the Dakotas and Minnesota though
with a large spread in possible outcomes confidence is low. The
overall consensus averages out to a fairly light event anyways.
Past wednesday when flow becomes more zonal aloft there is good
agreement on highs reaching the mid 30s in the north and low 40s
in the south with the NBM percentile reflecting this. This trend
of above normal temps looks to continue well in the December with
ridging likely being the dominant feature in the west with short
duration breaks.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 525 PM CST Thu Nov 30 2023
VFR conditions prevail at all sites this evening. Low to mid-level
stratus continues to push southeastward, and could bring MVFR CIGs
to the area for the overnight period and into early Friday
morning; however, Upstream observations are mainly VFR.
Otherwise, generally light westerly winds are expected through the
period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Lynch
SHORT TERM...JR
LONG TERM...TT
AVIATION...Lynch
Area Forecast Discussion
National Weather Service North Platte NE
535 PM CST Thu Nov 30 2023
.KEY MESSAGES...
- Minor threat for flurries/sprinkles Saturday across southern
Nebraska with no accumulations or impacts expected.
- Dry conditions with unseasonably warm temperatures in the 50s
and 60s return next week with breezy winds (gusts of 20 to 35
mph) at times.
&&
.SYNOPSIS...
Issued at 245 PM CST Thu Nov 30 2023
Recent GOES-16 WV and RAP 500-mb analysis showed a closed low
pressure system centered over the Hudson Bay with a trough extending
into the Great Lakes region. Another upper-level low was tracking
into the central Gulf of Alaska. Downstream of this feature, an
elongated shortwave trough was noted off the coast of British
Columbia, extending south-southeast off of the West Coast of the
United States. In between the Hudson Bay low and the west coast
shortwave, an upper-level ridge was apparent over southern British
Columbia, extending north into the Northwest Territories. South of
this feature, a southern-stream upper-level shortwave was centered
across the New Mexico/Texas border. At the surface, low
pressure was centered over the northern Michigan with an
associated cold front extending southwest into southern Kansas,
where it meets another surface low pressure situated across
northern Oklahoma. This surface cold front swept through the
local area last night resulting in colder afternoon temperatures
today as compared to yesterday, ranging from 34 degrees at
Gordon to 41 degrees at North Platte as of 2 PM CT.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 245 PM CST Thu Nov 30 2023
Tranquil and dry will be the story in the short term period for
western and north central Nebraska. Cloud cover will continue to
increase this evening with mostly cloudy to overcast skies
expected tonight through Friday evening. Unfortunately, these
cloudy skies will hinder any potential aurora viewing across
western and north central Nebraska tonight. Refer to the Space
Weather Prediction Center (SWPC) for more information on the
aurora forecast for tonight. These clouds will also keep
overnight lows on the warmer side of things, falling into the
teens.
The forecast remains quiet as we head into the end of the work
week on Friday with another day of below normal temperatures and
dry conditions expected. Daytime highs will remain in the 30s
across the area, though on the bright side (at least for those
who dislike the cold), much warmer temperatures are on tap as
we head into the long term period for next week.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 245 PM CST Thu Nov 30 2023
The upper-level shortwave currently over the west coast will emerge
across the Plains early Saturday with a surface trough moving
through western Nebraska and associated warm front across northern
Oklahoma. It continues to appear there may be just enough moisture
and forcing to squeeze out some flurries and/or sprinkles across
southern Nebraska Saturday morning into the early afternoon.
However, recent trends amongst deterministic and ensemble solutions
continue to back off on the potential for precipitation with the
outliers being the NAM12 and GFS deterministic solutions, with
both continuing to be rather optimistic on "some" measurable
precipitation occurring. When looking at the GFS Ensemble
solution, less than 10% of the 30 members highlights the
potential for flurries/sprinkles. This forecast challenge will
continue to be monitored with subsequent forecasts where the
mention of any precipitation may need to be removed completely or
increased some based on model trends.
Dry conditions return with a gradual warm up beginning on
Sunday as an upper-level ridge takes hold over the region (and
bulk of the CONUS at that). This will result in highs climbing
into the 50s and 60s by the middle of next week which are 20 to
25 degrees above normal for the beginning of December. This
signal for unseasonably warm temperatures is supported by both
the NAEFS and ECMWF ensemble guidance which is suggesting that
the mean temperature at H85-5 will meet or exceed the 90th
climatological percentile Wednesday, Thursday, and Friday.
Furthermore, the ECMWF EFI (Extreme Forecast Index) has begun to
show increased confidence of anomalous event, such that the SoT
(Shift of Tails) is nonzero across portions of the northern
Plains.
In addition to warmer temperatures, breezy winds with gusts of 20 to
35 miles per hour will be felt at times in response to a tightened
surface pressure gradient (SPG) across the area. The strongest
of winds are forecast to occur late Sunday into Monday,
primarily focused over the Panhandle into the western Sandhills
where an increased potential for gusts over 35 miles per hour.
This potential is highlighted by the ECMWF EFI/SoT which has
begun to show increased confidence in an anomalous event
potentially impacting portions of the region. Though the
strongest of winds will impact our neighbors to the west,
coinciding with where the tightest gradient is, these locally
breezy winds may result in holiday decorations or loose
objects/trash cans to be blown around.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 534 PM CST Thu Nov 30 2023
Increasing clouds are expected tonight with ceilings lowering to
near 8000 feet. Overcast skies continue through Friday afternoon,
however, winds remain below 10 knots.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Kulik
Area Forecast Discussion
National Weather Service Marquette MI
915 PM EST Thu Nov 30 2023
.SHORT TERM...(Through Tonight)
Issued at 226 PM EST THU NOV 30 2023
Key Message:
- Isolated to scattered light lake effect snow showers/flurries in
areas favored by northwest winds off of Lake Superior tonight,
mainly e.
Water vapor imagery and RAP analysis show a deep mid-level low
centered over southern Hudson Bay. In the circulation around this
feature, a shortwave has been streaking across northern
Ontario/northern Lake Superior today. Its associated sfc cold front
has cleared the fcst area recently. In its wake, nw winds and caa
have resulted in stratocu developing off of Lake Superior, and a few
flurries/sprinkles have also occurred from nw Upper MI eastward.
Current temps are in the mid 30s to lwr 40s F.
CAA will send 850mb temps down to about -10C tonight, and with Lake
Superior sfc water temp 5-6C on avg, temp difference supports the
potential of wnw to nw flow LES. That said, incoming air mass is
dry, inversions are low at 4-5kft and low-level flow becomes
increasingly anticyclonic. RAP/HRRR show a higher inversion based
upwards of 6kft, but they are even more pronounced with the
drying/inverted-v profile look blo cloud base. The DGZ is at or
above the inversion base as well. Put it altogether and any LES
tonight will be light, much of it may not be much more than
flurries. Will keep pops in the schc/low chc range of 15-30pct,
mainly across the e where longer nw fetch across the lake works to
offset the dry air. With regard to the potential aurora tonight,
lake effect clouds under wnw to nw flow will pose viewing issues. S
central Upper MI will likely have the least cloudiness. Some areas
where wnw to nw winds are downsloping will also see more breaks in
the clouds. Expect min temps in the mid teens to mid 20s F in
general, coldest interior w vcnty of MI/WI stateline.
.LONG TERM...(Friday night through Thursday)
Issued at 311 PM EST THU NOV 30 2023
Key Messages:
-Dry Friday and Saturday under high pressure
-Periodic light snows next week, best chance on Sunday.
-Normal to above normal temps to prevail over the next week with
warmest conditions late next week.
The forecast ahead will be characterized by normal to above average
temperatures with a few shots of snow, but nothing impactful
expected. Starting with Friday, the 500mb trough over Hudson Bay
that has been the driver of the local weather lately will retreat
northwards. A shortwave trough will be quickly ejecting northeast
out of the Southern Plains, but a 12Z GEFS-mean 1017mb surface high
over western Lake Superior will force the low associated with the
shortwave trough to remain too far south to bring any precipitation
to the UP. The cloud shield from the low is forecast to reach over
the UP, which may have some implications for aurora spotting, but
confidence is low as there is considerable spread in the NBM members
for sky cover through Saturday. Another question will be whether or
not any lake effect clouds or snow showers will develop. Some CAMs
are picking up on a potential southwesterly lake effect band over
the western Lake Superior waters though not much over land. With
plenty of dry air in the moist-biased NAM soundings and anticyclonic
flow at the surface due to the surface high, PoPs have been removed
from the forecast through Saturday evening. The CAMs do bear some
monitoring going forward for the next couple of forecast packages as
the temperature gradient from the lake to 850mb is right on the
margins for lake effect to occur.
Going into Sunday, a pair of troughs will move towards the Upper
Great Lakes. One of these will take a fairly typical clipper track
while the other looks to take a very similar track and intensity to
the Friday shortwave. Depending on how the surface lows and upper
troughs interact and phase, some light snow showers are possible
with perhaps a little rain mixing in as highs in the south have a
greater than 90 percent chance of going over the freezing mark per
the NBM. Once this passes, ridging overhead for Monday should keep
the forecast dry before precip chances return for Tuesday with
another clipper shortwave diving south from Canada. From here,
ensemble and deterministic guidance spread increases, but the
general pattern is the same: a continued train of weak shortwaves
passing approximately every other day with sub-advisory snowfall
amounts. 12Z GEFS meteograms only show one member with more than
half a foot of snow total through December 10th, and the GEFS mean
snowfall total is under a half foot well into mid-December, so
confidence in a big winter snowstorm is low for the foreseeable
future. Additionally, GEFS mean 850mb temperatures are also too warm
for lake effect snow.
The most notable weather feature this forecast package may be the
potential for record warmth next Thursday. The operational NBM has
fluctuated throughout today regarding whether the record December
7th high of 38 in 1968 will be tied or broken, though the latest NBM
25th-75th percentile range for MaxT that day is 33 to 40, so a wide
range of outcomes is still possible. Nevertheless, with cluster
analysis showing ridging being preferred by ensembles going into mid-
December, unseasonable warmth is the most likely outcome for
temperatures to begin December.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 915 PM EST THU NOV 30 2023
VFR conditions are expected to prevail through the TAF period.
Periods of bkn/ovc stratus will be likely with cigs around 3.5-5kft
for the first 6 hours of the TAF period. Low (30%) chance that a
lowering inversion could support brief MVFR cigs at IWD/SAW through
12Z. Lower clouds should scatter out late tonight into Friday.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 311 PM EST THU NOV 30 2023
Northwest wind gusts of up to 25 knots will fall below 20 knots
overnight and with high pressure approaching, winds will remain
light and variable into the weekend. Weak troughs aloft are expected
to pass through the Upper Great Lakes to end the weekend and through
the midweek forecast, keeping winds under 20 kts. The next chance
for wind gusts over 20 knots will be late Wednesday as southwesterly
winds gust to 25 knots. Significant wave heights should remain at 5
feet or below through the forecast period and no heavy freezing
spray is expected.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...GS
AVIATION...Thompson
MARINE...GS
Area Forecast Discussion
National Weather Service Tallahassee FL
901 PM EST Thu Nov 30 2023
...New UPDATE, MARINE...
.UPDATE...
Issued at 900 PM EST Thu Nov 30 2023
Adjusted temperatures to start the evening a little cooler but
still expected to be warmer than last night with lows only making
down to the upper 40s and low 50s due to cloudy skies preventing
the radiational cooling events we`ve experienced over the last
couple of nights.
&&
.NEAR TERM...
(Through Friday)
Issued at 333 PM EST Thu Nov 30 2023
Much warmer overnight low temperatures are expected across the
forecast area as surface high pressure moves off to the east.
Easterly flow will bring increasing dewpoints overnight and through
Friday ahead of our next period of active weather. Overnight low
temperatures will generally range roughly 15 to 20 degrees warmer
than Thursday morning values. The only forecast concerns overnight
will be patchy fog across south-central GA and the eastern Florida
Big Bend as low-level moisture return and cool temperatures keep a
potential for fog around.
The warming and moistening trend continues into Friday ahead of our
next weather system. A band of elevated southwesterly flow will lift
north over the region as a weak frontal boundary lingers over the
region. With a steady supply of warm air advection, a broad area of
showers and storms will develop by later in the afternoon and
evening hours across the western portions of the forecast area. The
Storm Prediction Center currently has the western half of the
forecast area under a marginal (level 1 of 5) risk for severe
weather. The main concerns will be the potential for a few isolated
strong/damaging wind gusts and possibly a few tornadoes due to the
enhanced low-level shear near the weak frontal boundary. A lack of
sufficient instability will keep the overall severe weather threat
low, especially given the best kinematics lifting quickly off to the
north in the evening hours. Regardless a very isolated severe threat
could linger into the early hours of Saturday morning before our
next wave arrives and brings more active weather into the rest of
the weekend.
&&
.SHORT TERM...
(Friday night through Saturday night)
Issued at 333 PM EST Thu Nov 30 2023
A warm front pushing north of the region puts us solidly in the
warmer sector Friday night. This should keep temperatures quite mild
with lows only expected to drop into the middle to upper 60s Friday
night into Saturday morning as dew points surge into the 60s area-
wide.
A low-level jet (LLJ) at 850mb is forecast to strengthen over
southern Alabama, western Georgia, and the Florida Panhandle during
the day Saturday. As such, there is ample shear around the region.
However, instability appears to be lacking on guidance at the
moment. In other words, another potential high-shear/low-CAPE event
is possible during the period. The better environment for storms
appears to be over southeastern Alabama, the Florida Panhandle, and
into southwestern Georgia Friday night into Saturday. The Storm
Prediction Center (SPC) has maintained a Marginal Risk (level 1 out
of 5). Isolated damaging wind gusts are the primary concerns, while
a tornado or two cannot be ruled out at this time. The main limiting
factors are the lack of upper-level support and relatively low
instability thanks to ample cloud cover expected.
Rain, and quite a bit of it, is possible during this period; more
information on this in the Hydro section below. Some of the
latest Convection Allowing Models (CAMs) continue to advertise a
couple of distinct waves of rain. For instance, the 12Z HRRR has
the first wave of rain in the period could be coming ashore along
the Florida Panhandle before heading into southeastern Alabama
Friday night into early Saturday morning. Other CAMs, like the
WRF-NSSL, FV- 3, and the experimental RRFS, keep the same batch
over the Gulf of Mexico. Due to the potential for locally heavy
rain, the Weather Prediction Center (WPC) has maintained a
Marginal Risk (Level 1 of 4) for Excessive Rainfall across the
western 3/4 of the region through 12Z Saturday. Another wave of
rain, which most CAMs agree on based on the 12Z HREF paintball, is
forecast to arrive Saturday morning. Yet another wave of rain is
possible later Saturday afternoon into Saturday evening. This
warrants some concerns for heavy rainfall producing localized
flooding. This has led to WPC issuing a Marginal Risk (level 1 of
4) for Excessive Rain for Saturday into Saturday night for all but
the southern FL Big Bend.
As far as temperatures are concerned for Saturday, clouds and a
couple waves of rain should keep temperatures in the lower to middle
70s for daytime highs. Another night in the lower to middle 60s is
forecast Saturday night.
&&
.LONG TERM...
(Sunday through Wednesday)
Issued at 333 PM EST Thu Nov 30 2023
With a robust plume of moisture still in place during Sunday
afternoon and evening (PWAT >= 1.5"), an additional 0.25" to 0.5" of
rain is possible areawide to cap off the weekend. The front should
fully clear the region by early Monday morning, with some light
shower activity possible through late Monday morning in the front`s
wake. Temperatures should noticeably cool after the front`s passage,
with highs decreasing from low-to-mid 70s on Sunday to mid-60s to
low-70s on Monday.
The dry air that filters in behind the front on Monday should
persist throughout the week, keeping rain chances near-zero through
the end of the week. Temperatures gradually decrease throughout the
rest of the week, with highs reaching into the low-60s to upper-50s
and lows settling into the low-40s to upper-30s by Thursday.
&&
.AVIATION...
(00Z TAFS)
Issued at 706 PM EST Thu Nov 30 2023
The air mass is currently undergoing a rapid transition from dry
and stable, to moist and less stable. Just above the surface,
southerly low-level flow will increase through tonight, advecting
increasing amounts of moisture from the Gulf. The southerly low-
level jet will increase enough over ECP and DHN around sunrise to
include a mention of low-level wind shear in those TAFs.
As increasingly moist air interacts with the cool nearshore Gulf
waters on Friday, low stratus will develop and thicken along the
coast during the day, with southerly flow spreading it inland to
ECP, TLH, DHN and possibly ABY toward sunset tomorrow. Stratiform
rain will spread in from the west late in the TAF period,
affecting ECP and DHN, and possibly reaching TLH and ABY during
the valid period.
&&
.MARINE...
Issued at 900 PM EST Thu Nov 30 2023
Winds will become more southerly and increasing to about 20kts
overnight for our offshore western legs as the next frontal system
approaches from the west. Small Craft Advisories remain in effect
for the offshore Gulf waters west of Apalachicola tonight through
Friday morning. Chances for showers and thunderstorms increase
Friday afternoon and will continue through the weekend before
clearing out following a cold front Sunday night into Monday
morning.
&&
.FIRE WEATHER...
Issued at 333 PM EST Thu Nov 30 2023
Fire weather concerns will be low through the weekend with high
chances for wetting rains expected to move in beginning Friday
evening and into the weekend. The greatest confidence in these
wetting rains will be across southeast Alabama and the Panhandle.
Drier conditions are not likely to arrive until next week.
&&
.HYDROLOGY...
Issued at 333 PM EST Thu Nov 30 2023
Wetter weather is on the way for the first weekend of December
Latest forecast amounts have come down slightly but are still in the
general 1" to 4" range with higher amounts possible in the Florida
Panhandle and southeastern Alabama. Localized flooding is possible,
especially in urban, low-lying, and poor drainage areas. Locations
that experience heavy rain rates in a short period of time or
training convection are also vulnerable, which current models
suggest would be along the coast of the Florida Panhandle.
Flash Flood Guidance (FFG) shows that between 2.5" to 4" in 1 hr
would be needed to induce flash flooding, 3" to 5" in 3 hrs, and
4" to 6" in 6 hrs. Given the ongoing, but slightly improving
thanks to last weekend`s rain, drought, and low to very low local
river levels, significant flooding is not anticipated.
Drier weather looks to return early next week.
&&
.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 52 74 66 74 / 10 40 60 80
Panama City 53 75 68 75 / 10 80 80 90
Dothan 49 73 65 72 / 20 80 90 90
Albany 47 74 64 73 / 10 50 80 90
Valdosta 49 79 64 76 / 0 30 50 70
Cross City 52 80 64 79 / 10 10 30 40
Apalachicola 58 72 69 74 / 10 50 70 80
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk from 1 AM EST /midnight CST/ Friday
through late Friday night for FLZ108-112-114-115.
GA...None.
AL...None.
GM...Small Craft Advisory until 9 AM CST Friday for GMZ770-772.
&&
$$
UPDATE...Montgomery
NEAR TERM...Dobbs
SHORT TERM...Reese
LONG TERM....Szot
AVIATION...Haner
MARINE...Montgomery
FIRE WEATHER...Dobbs
HYDROLOGY...Reese