Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/08/24
Area Forecast Discussion
National Weather Service La Crosse WI
505 PM CST Wed Feb 7 2024
.KEY MESSAGES...
- Record breaking warmth continues for tonight into Thursday
before a cold front arrives Thursday evening. Lows tonight
will be 15 to 20 degrees above our normal HIGH temperatures
for this time of year!
- Light rain showers move through Thursday morning, with the
potential for isolated thunderstorms Thursday afternoon.
There is a non-zero threat for a severe storm in far southwest
Wisconsin and east-central Iowa IF the ingredients can line
up correctly.
- Temperatures cool for the weekend and next week, but remain 5
to 10 degrees above normal. There are a few rogue chances for
precipitation, but impacts and potential look low.
&&
.DISCUSSION...
Issued at 230 PM CST Wed Feb 7 2024
Tonight - Thursday Morning: Warm and Windy
Broad longwave troughing exists across the western CONUS in
water vapor imagery this afternoon with multiple weak ribbons
of theta-e advection bringing clouds and even some light
sprinkles. The pressure gradient has been steadily increasing
over the Central Plains today as lee troughing along the Front
Range continues to deepen ahead of the first significant vort
lobe ejecting from the base of the longwave. As the low pulls
off the Front Range this evening, a 40-50 kt LLJ overspreads the
region and helps keep blustery winds and warm temperatures
through the night, especially at higher elevations. Forecast
lows of 40 to 45 degrees are a solid 15 to 20 degrees above the
normal highs for this time of year and set the stage for the
warmest day of the stretch on Thursday.
Low level moisture increases after midnight with most guidance
bringing in stratocumulus and showers during the morning hours.
QPF amounts from the various global and convective allowing
ensembles with this first wave remain on the low side and
impacts look minimal. Surface winds steadily increase through
the overnight and morning hours with gusts of 25 to 40 mph
expected during the morning hours at higher elevations.
Thu Afternoon: Thunderstorms, Conditional Severe Weather Risk
As if the April-like temperatures weren`t enough, we are looking
at a conditional severe weather(!) threat across east-central
Iowa and southwest Wisconsin Thursday afternoon. Being in the
left front quadrant of a 110-kt jet streak and cyclonically
curved 0-3-km hodographs would support organized updrafts and
low-level rotation, but the degree of destabilization and
heating ahead of an advancing cold front will be the key to
whether we even see convective initiation. The HRRR/RAP as well
as the EC deterministic guidance depict surface temperatures
rising into the mid to even upper 50s by early afternoon with
dewpoints in the upper 40s. Steepening low level lapse rates in
conjunction with this heating would yield SB/MLCAPE values of
500-1000 J/kg.
Forecast soundings show this destabilization happening in a
VERY narrow spatiotemporal window ahead of the front and any
cooling to the low level thermal fields would rapidly erode any
possibility of seeing thunderstorms, let alone convection strong
enough to support severe weather. The explicit reflectivity
fields from the 06/12/18Z HRRR have been steadfast in developing
convection along the front as well, which when combined with
the favorable background kinematic/shear profiles, has yielded
the issuance of a Marginal Risk for the southern portions of the
forecast area. The best window for severe weather would be
limited in time to between 21 and 00Z before cooling ensues
with the loss of solar insolation and cold air advection behind
the front.
Technically all hazards (60 mph winds, quarter size hail, and a
brief, weak tornado) are on the table with this event. It would
take a remarkable alignment of ingredients to spawn a tornado,
thus for now we are mainly messaging the hail and wind threats
with any severe storms.
Friday - Wednesday: Seasonably Mild, Low Precipitation
West to northwest flow sets in for the weekend and next week
with multiple perturbations working through over the course of
the period. Given the progressive pattern and limited moisture,
model guidance is widely spread on the timing and amounts of any
rainfall, if at all. One such wave drives through the region on
Monday with the GEFS suite being the most aggressive in any
light QPF production. Confidence in any precipitation timing
beyond Monday wanes even further and the current forecast
remains dry for the week. However, one cannot rule out some
light rain/snow at points during the week depending how the
pattern shakes out.
Lower tropospheric temperatures cool within this northwest flow
regime, but the coldest air remains confined in Canada and
several shots of moderating west to southwest flow permeate the
forecast. The end result is that temperatures are expected to
remain 5 to 10 degrees above average through the week, though
there is modest 7 to 10 degree interquartile spread in the NBM
max temperature guidance owing to the timing differences of the
aforementioned waves. Temperatures do look to slide back to near
normal by next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 505 PM CST Wed Feb 7 2024
CIGS: upper level cirrus shield persists overnight, gradually
lowering to low VFR/MVFR btwn 12-15z Thu. Short term guidances
favors holding onto the lower cigs, dropping some moving into the
afternoon. Some variability there though and could see some
fluctuations in cigs through the day. Also, potential for a clear
slot post the morning showers, but current trends holds that farther
south (IA/NW IL).
WX/VSBY: scattered -shra look to track northeast across the area Thu
morning. A few more showers (potentially an isolated storm) could
organize around a cold front for later afternoon/evening - bringing
another shot for pcpn.
WINDS: breezy southerly fetch to continue through Thu. Gusts will be
inhibited somewhat by relatively shallow inversion (1.5kft), but
this deepens during the day Thu. Above the inversion, the low level
jet still expected to blow from 45 to 50 kts with LLWS concerns at
KLSE.
&&
.CLIMATE...
Issued at 230 PM CST Wed Feb 7 2024
Based on the forecast temperatures, record highs and warm lows
will be possible today and Thursday across much of the forecast
area. Below are the records for La Crosse WI and Rochester MN.
La Crosse
Date Record High Record Warm Low Forecast High Forecast Low
----- ----------- --------------- ------------- -------------
2/7 54F(1878) 35F(1970) 52F 36F*
2/8 51F(2002) 36F(1938) 56F* 43F*
Rochester
Date Record High Record Warm Low Forecast High Forecast Low
----- ----------- --------------- ------------- ------------
2/7 52F(1987) 30F(1920) 50F 35F*
2/8 49F(2002) 34F(1966) 54F* 40F*
* - Near record to record temperatures forecast
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Skow
AVIATION.....Rieck
CLIMATE...Boyne/Skow
Area Forecast Discussion
National Weather Service Quad Cities IA IL
610 PM CST Wed Feb 7 2024
.KEY MESSAGES...
- Warm and windy Thursday, with record highs and warm lows possible.
- Chance of rain (35-55%) Thursday morning, with light QPF less than
a tenth of an inch. Low chance (< 10%) of embedded thunder.
- Conditional threat of isolated severe storms late Thursday
afternoon and evening.
- Turning colder and more seasonable this weekend and next week,
with mostly dry conditions.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 213 PM CST Wed Feb 7 2024
After a cold start with dense fog in our northeast third,
temperatures have slowly risen through the day. This was due to our
high clouds that remained broken/overcast and limited mixing.
Temperatures at 2pm were in the middle 40s to lower 50s, which is 14
to 17 degrees above normal. It has been quite the warm start to
February! In fact, the 1st 6 days of the month ranks as the 3rd
warmest start for MLI and DBQ. You need to go back to 2005 to see
a comparable start to February.
This Afternoon-Tonight...an area of low pressure will deepen to
around 990mb across the eastern Dakotas. This will keep us firmly in
the warm sector, with breezy south winds increasing through the
night. Very mild temps will be seen, with readings only dropping
into the lower 40s. A strong LLJ and moisture transport will occur
ahead of a lead shortwave currently over New Mexico. Very little to
no precip is expected prior to 12z Thursday.
Thursday...strong forcing for ascent aided by right entrance region
of 130kt jet streak will support a line of showers moving east
through the CWA in the morning hours. Latest CAMs and the 12z HREF
local probability matched mean (LPMM) reflectivity progs show
this progression moving east approx. 13-17z. Forecast soundings
show this activity to be elevated, with little to no instability
to work with. That said, the RAP 700-500mb theta-e lapse rates
approach 0, so some embedded thunder is not out of the question.
Attention then turns to how quickly the atmosphere can recover by
late afternoon. Strong winds will continue to advect moisture into
the region with dewpoints rising into the mid to upper 40s by the
afternoon. Latest NBM has only 30% of its members reaching 50 degree
dewpoints in a narrow swath from IOW to PIA by 3pm Thursday.
The 12z HREF also has 750-1000 J/Kg of MUCAPE building into
middle part of the CWA. The strongest forcing however, will be
displaced from this instability across northeast IA and
southeast MN in closer proximity to the main low. Definitely not
a slam dunk for storms and that all being noted and seeing the
latest 18z HRRR run, isolated severe storms will be possible in
the 21-02z time frame. There could be two areas to watch in our
CWA (the far eastern counties in north central IL and northwest
of CID). With strong deep layer and 0-1 km shear in place,
can`t rule out a tornado or two, along with a damaging wind
risk. Storm motion will be very fast so there will not be a lot
of residence time of storms at any one point tomorrow
afternoon. SPC has a Day 2 Marginal Risk (level 1 of 5)
northeast of a line from Iowa City to Galesburg.
Temperatures/Wind:
Our 1st 60 degree day could very well occur tomorrow with record
highs possible. See climate section below for details. The last 60
degree day we had in the Quad Cities was Dec 8th. Went just above
the NBM 50th percentile for highs and could very well be too low if
we can mix to 900-850mb. Cloud cover trends will be important to
monitor tomorrow morning for this potential. In addition, winds at
top of mixed layer on RAP/NAM soundings are near 50kts, so winds
gusting over 40mph could be possible in the afternoon. An SPS may be
needed if this becomes realized.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 213 PM CST Wed Feb 7 2024
Thursday Night-Friday...another mild night and warm day to end the
work week is forecast. 850mb temps will remain in the 2-4C range
with decreasing clouds Thursday night. Overnight lows will drop into
the upper 30s northwest to lower 40s southeast. A weak surface low
will develop over the central Plains on Friday and track east into
northern MO. This will keep us mostly dry with westerly winds
through the day Friday. Highs will range from the upper 40s to
upper 50s.
Friday Night-Wednesday...A cold front at the surface and aloft will
push through Friday night, with a large area of high pressure
building into the upper Midwest. 1000-500mb RH layer progs and
forecast soundings show a rather dry profile during the fropa, so am
only expecting an increase in clouds Saturday. Dry conditions and
closer to seasonable temps will be seen through the period. Expect
highs in the lower 40s and Lows in the mid to upper 20s. This is
still above normal for early February. A digging positively tilted
longwave trough will track over the desert SW and southern Plains
Saturday through Monday with 12z deterministic and ensembles still
keeping the bulk of its precip shield to our south. This is
also shown in the QPF from WPC for this period. Two northern
stream waves will track across the upper Midwest next week, but
model trends keep them to our north at this time. While we will
be colder, it seems any precip chances will be just beyond our 7
day forecast.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 552 PM CST Wed Feb 7 2024
A strong SSW low-level jet with 40-50 kt winds at 2000 ft AGL
will lead to a period of LLWS overnight into Thursday AM. Then a
band of light to briefly moderate rain is expected to quickly
cross through the area from mid to late Thursday morning, only
lasting 1-2 hours at the terminals. The precipitation will
likely be accompanied by MVFR ceilings that will linger into the
early afternoon. Very isolated thunderstorms could develop
Thursday afternoon, but have too low of confidence to mention
in the TAFs with this update. At the surface, S to SSW winds
will increase overnight into Thursday with peak gusts between 30
to 35 kts from the late morning through the afternoon.
&&
.CLIMATE...
Issued at 218 PM CST Wed Feb 7 2024
Record High Temperatures:
February 7:
KCID: 57/1987
KDBQ: 51/1882
February 8:
KCID: 57/1925
KDBQ: 55/1925
KMLI: 63/1990
February 9:
KCID: 56/2009
KDBQ: 51/2009
Record Warm Minimum Temperatures:
February 8:
KDBQ: 37/1938
KMLI: 40/1925
February 9:
KDBQ: 42/1966
KMLI: 43/1966
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gross
LONG TERM...Gross
AVIATION...Uttech
CLIMATE...Gross
Area Forecast Discussion
National Weather Service Indianapolis IN
928 PM EST Wed Feb 7 2024
.Key Messages...
- Rain chances Late Thursday Afternoon and evening.
- River flooding along the Wabash ending by Wednesday night.
- Wind gusts over around 30 mph likely Thursday with a few gusts to
40 mph possible Thursday night.
- Rain chances increase late Friday night into Saturday.
&&
.Forecast Update...
Issued at 927 PM EST Wed Feb 7 2024
Breaks in the thick cirrus, that was moving overtop the high
amplitude ridge, dry boundary layer and surface and very light to
calm winds, have allowed temperatures at a few locales to rapidly
drop to the upper 30s and lower 40s. So had to lower nighttime
temperatures a few degrees at some sheltered locations. That said,
as the surface low pressure gradient tightens overnight, ahead of
the northern Plains low pressure system, winds will become southerly
and increase in speed and should result in steady or slowly rising
temperatures. Daybreak temperatures will likely be in the upper 30s
to lower 40s, which will be a change from the previous frosty
mornings.
&&
.Short Term...(This evening through Thursday)
Issued at 255 PM EST Wed Feb 7 2024
Synopsis -
Surface analysis early this afternoon shows a broad area of high
pressure over the east coast. Influence of this high extended west
to the eastern Great Lakes, the Ohio Valley and the Gulf Coast.
Weak southerly flow was found across Central Indiana. Low Pressure
was found over WY. This was resulting in a moderate pressure
gradient across the plains states, which was slowly pushing eastward.
Aloft, water vapor showed a strong ridge in just east of the
Mississippi Valley. This was resulting in lee side subsidence across
the eastern third of the United States including Indiana.
GOES16 shows ridge riding cirrus flowing over the ridge and spilling
into Indiana from the northwest. Radar was quiet across the region.
ACARS soundings show a very dry column within the lower and middle
levels.
Tonight -
Partly cloudy and dry weather with mild temperatures are expected
tonight. Models suggest the ridge axis aloft will push to Indiana
this evening before exiting to the east overnight. This will keep
continued subsidence in play along with a lack of lower level
clouds. The controlling area of high pressure will also drift east,
allowing the pressure gradient to the west to advect into the Ohio
valley late tonight and Thursday. Models also depict late tonight
and on Thursday morning an moderate 50 knt LLJ streaming across
Central Indiana. However, overall deep moisture with this system is
lacking. Forecast soundings across the area continue to reveal very
dry lower and mid levels, due to the past few days of subsidence.
Thus we will only expect continued high clouds passing across
Indiana, advecting from the plains states. Clouds and increasing
winds allowing mixing overnight should result in mild low
temperatures with lows in the upper 30s and lower 40s.
Thursday -
The upper ridge axis will be well east of Indiana by Thursday
morning and will continue its eastward progression through the day.
Meanwhile an upper trough will be working through the northern
plains and upper Midwest. Much of the best upper forcing with this
feature looks to remain well north of Central Indiana over the
western Great Lakes before streaming farther away into Ontario.
However, the surface cold front with this feature is expected to
approach Central Indiana on Thursday before passing across the state
through the day. The previously mentioned LLJ will remain in play
through the day along with the passing cold front. However moisture
remains an issue. Forecast soundings fail to show deep saturation,
but lower and mid levels do show some saturation arriving by
afternoon. Pwats are suggested to reach near 0.77in. HRRR does
suggest some scattered precipitation across Central Indiana Thursday
afternoon...albeit light and quick moving. DESI suggests several
members pushing an area of scattered light rain across Central
Indiana from 20Z onward. The quick moving precip should be light, as
many of the hours of the day will be dry. Thus will trend toward a
dry morning and early afternoon before adding pops late in the
afternoon as the cold front and these very light shows may pass.
Given the good mixing and warm southerly flow ahead of the front,
highs in the middle and upper 50s should be reached.
&&
.Long Term...(Thursday night through Wednesday)
Issued at 255 PM EST Wed Feb 7 2024
SYNOPTIC OVERVIEW
Upper-level flow across the CONUS can be described as highly
amplified, with a ridge axis over the Plains bounded by deep
troughing on either side. Indiana resides downstream of the ridge as
of this writing. High clouds have increased today ahead of an
approaching trough, currently over the Intermountain west. This
trough will induce cyclogenesis in the lee of the Rockies today. The
resulting low pressure center then races off to the northeast.
The low should pass far enough to our north that any significant
dynamic forcing bypasses Indiana. As a result, confidence in rain
continues to decrease. A few showers or sprinkles may still be
possible, especially Thursday night into Friday morning...but
overall rain threat appears minimal with perhaps a trace to a few
hundredths at most. Guidance shows a tight MSLP gradient with this
system, which may bring some warm yet gusty southwesterly winds
Thursday night into Friday. Gusts over 30mph are likely at times,
with a few gusts exceeding 40mph not out of the question. Such
strong warm southwesterly winds look to bring our warmest day in a
while, with highs reaching into the low 60s Friday.
As the low pulls away, it will drag a weak cold front into the
region which looks to stall out north of us near Chicago. This
boundary will set up a baroclinic zone that another upstream wave
will traverse. Uncertainty remains regarding this wave, with some of
the global models keeping it a bit more compact and potent...while
the NAM for instance keeps it elongated and weaker. Nevertheless,
they all show precipitation developing ahead of the fast-moving
system. Timing-wise, precipitation onset late Friday night or early
Saturday morning is most probable. Thermal profiles suggest that
rain is easily the only realistic precipitation type.
As the second system exits, only a slight southward push of colder
air ensues. The aforementioned baroclinic zone shifts southward as a
result, but not by much. The west coast trough looks to send one
final wave our way, which should arrive on Monday. Given the
baroclinic zone stretching further south, model soundings indicate
precipitation type may be a concern with this system...especially
near and north of the system`s center. Greater uncertainty in
guidance exists with this system, both in run to run consistency and
in system magnitude and location.
Beyond that, ensembles show a return to northwesterly flow and
potentially colder weather.
FORECAST CONFIDENCE
Confidence is increasing regarding Thursday night`s rainfall
potential. Trends have been drier, and now the vast majority of
guidance shows little in the way of measurable precip across
Indiana. Confidence for wind gusts over 30mph is high. Per DESI,
probability for gusts reaching 30mph is near 100 percent, with gusts
over 40mph rather high across our northwest at over 75 percent.
Additionally, very little spread exists amongst the various ensemble
members which indicates greater certainty in a particular scenario.
DESI probability drops significantly when looking at potential for
45mph gusts, indicating a much lower probability of reaching this
threshold.
Regarding Saturday`s system, confidence is moderate in terms of its
timing but low regarding precipitation amounts. Much of the
variability in guidance primarily resides in system strength, which
in turn affects how much precipitation develops ahead of it.
Regarding Monday`s system, confidence is quite low. Much variability
remains in model guidance and until a consensus emerges it is too
soon to talk about potential affects. The only thing with this
system where at least some confidence exists is its Monday arrival
time.
&&
.Aviation...(00Z TAF Issuance)
Issued at 611 PM EST Wed Feb 7 2024
Impacts:
- Non-convective low level wind shear possible 08z-15z
- Winds 170-210 degrees to 20+ knots and gusts to 30+ knots
after 15z Thursday
- MVFR ceilings and showers possible after 22z Thursday
Discussion:
Thick cirrus will stream in ahead of a departing high amplitude
ridge, that was extending from northern Ontario to the Gulf of
Mexico. Then, a low level jet will move overhead overnight and
Friday morning, ahead of a low pressure system. This will also
result in a strengthening surface pressure gradient and HI-Res model
soundings are suggesting 30+ knot winds may mix down aloft from the
2K foot inversion, Thursday afternoon. Otherwise, winds will be
southeast less than 10 knots tonight and south winds will sustain to
20+ knots Thursday afternoon. Finally, a few showers and maybe even
MVFR ceilings are possible late Thursday afternoon and evening.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Puma
Long Term...Eckhoff
Aviation...MK
Area Forecast Discussion
National Weather Service North Platte NE
528 PM CST Wed Feb 7 2024
.KEY MESSAGES...
- A fast moving system will bring the potential for rain
showers/isolated non-severe thunderstorm(s) this evening into
tonight across western and north central Nebraska. High
confidence (>70%) for minimal rain accumulations (0.1" or
less).
- The potential for a transition to snow overnight exists across
the Pine Ridge into the northwest Sandhills with high
confidence (>80%) for any accumulations to remain 0.5" or
less.
- Widespread, strong northwest wind gusts (35 to 45 mph) are
likely (>80%) on Thursday.
- Cooler temperatures this weekend into early next week, though remaining
at or slightly above normal for this time of year.
&&
.SYNOPSIS...
Issued at 331 PM CST Wed Feb 7 2024
Recent GOES-16 WV and RAP 500-mb analysis showed a ridge of high
pressure extending from the Gulf of Mexico north into the Great
Lakes region. Further to the west of this feature, an upper-level
trough across the Desert Southwest with a shortwave was noted
across Colorado. A potent upper-level shortwave was moving
southward across the offshore coastal waters of southern Oregon
and northern California. At the surface, a leeside trough was
apparent across northeast Colorado with an associated cold front
extending south-southwest across the southern Plains. Another
surface low pressure system was noted across northern South
Dakota with a Canadian cold front extending southwest into
southwest South Dakota. Southerly winds have increased this
afternoon for areas generally east of Highway 83 due to the
strong (50+ kt) low-level jet (LLJ) winds mixing down to the
surface with recent area observations of 25 to 35 mph. Well
above normal temperatures are being felt across western and
north central Nebraska with 3 PM CT readings ranging from 41
degrees at Gordon to 63 degrees at Imperial.
Visible satellite depicts a narrow band of clear skies extending
from northeast Colorado, northeastward into Rock, Brown, and
Keya Paha Counties. This corridor will be the focus for the
potential of an isolated thunderstorm or two this evening.
Convection was observed upstream in northeastern Colorado
a few hours ago with abundant cumulus clouds.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 331 PM CST Wed Feb 7 2024
The upper-level shortwave will continue to shift northeastward into
the northern Plains through tonight with strengthening southwesterly
mid/upper-level flow. The strong LLJ combining with robust
instability (SBCAPE ~250 J/kg) and steepening mid/upper-level lapse
rates (8+ C/km) will create an environment supportive of an
isolated non-severe thunderstorm or two. The main component we
are missing is moisture/buoyancy and with dew points in the mid
30s to mid 40s the threat for severe thunderstorms is rather
low. With all that said, occasional gusty winds will be possible
in any thunderstorms that develop. The potential for
thunderstorms will be highly diurnally driven with the main
"threat" area being across the Sandhills and southwest Nebraska.
Outside of the thunderstorm potential, rain showers are the
more likely scenario for most areas this evening into the
overnight period. The aforementioned Canadian cold front will
begin to advance southeastward into the northwest Sandhills
tonight/early Thursday morning with a push of colder air behind
it. Overnight low temperatures falling below freezing across the
Sandhills will support a transition from rain to snow which may
result in a dusting of snow primarily across the Pine Ridge and
northwest Sandhills. The NBM probabilities for >0.1" of snow
indicates a 30% or lower probability across the northwest
Sandhills with probabilities for >0.5" of snow dropping down to
10% or lower. While the potential for >0.5" is non-zero, there
is high confidence (>80%) that any snow that does accumulate
will remain a few tenths of an inch at best. Anticipate the
bulk of precipitation to have ended Thursday morning, though
some lingering showers will be possible into the afternoon
hours. There is also low potential for fog development tonight
across the the northwest/northern Sandhills, however, it is non-
zero. Should any fog develop, it should remain localized with
minimal impacts anticipated. With the frontal passage (FROPA),
winds will strengthen and veer towards the northwest Thursday.
Strong pressure rises (2 to 4 mb/3 hour) and strong cold air
advection (CAA) behind the front will result in widespread,
strong northwest wind gusts of 35 to 45 mph to encompass western
and north central Nebraska. These strong winds decrease around
sunset Thursday as the surface low over Dakotas continues
northeast into the Upper Midwest and the LLJ subsides across the
area. High temperatures will be cooler as compared to previous
days in the 40s (along and north of I-80) to mid 50s (south pf
I-80), though still remaining 5 to 10 degrees above normal for
the beginning of February.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 331 PM CST Wed Feb 7 2024
The upper-level pattern for the start of the long term period will
be defined by low pressure situated across Ontario with a trough
extending south into the Upper Midwest and Great Lakes regions. An
embedded shortwave within this main trough will exit from Colorado
into Kansas, passing just to the south of our forecast area. Behind
this system comes the next main trough digging southward out of the
Great Basin into the Desert Southwest on Saturday. This system
appears to clip far southwest Nebraska, however, the best forcing
and moisture will remain to our south. There may be just enough to
bring light snow showers to southwest Nebraska, though low
probabilities of 20 to 40% exist. Confidence is rather low on this
weekend`s precipitation chances, thus cannot argue with the NBM`s
forecast of slight chance/chance (20 to 35%) PoPs.
For Sunday into the middle of next week, dry conditions with
seasonal temperatures in the 40s settle into the region with
northwest/westerly flow aloft expected.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 527 PM CST Wed Feb 7 2024
A few aviation weather concerns exist across western and north
central Nebraska terminals during the forecast period. Showers
with a few thunderstorms will continue to develop along a cold
front this evening, while southerly winds gust 25+ kts ahead of
the boundary. Precipitation grows in coverage this evening as
the front pushes east, also resulting in lower ceilings and a
rapid transition to northwest winds. In addition to widespread
MVFR to IFR ceilings, fog will also develop in northwest
Nebraska overnight. Clouds lift toward midday Thursday, but
gusty northwest winds remain.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Snively
Area Forecast Discussion
National Weather Service Melbourne FL
1000 PM EST Wed Feb 7 2024
...New UPDATE, MARINE, AVIATION, HYDROLOGY...
.UPDATE...
Issued at 1000 PM EST Wed Feb 7 2024
Winds continue to decrease this evening as RAP analysis indicates
a weakening of the surface pressure gradient over the area.
North-northeast winds decrease further overnight and up to
daybreak Thursday. A low to mid-level marine cloud layer is
streaming from northeast to southwest, reaching areas along and
east of Interstate 95. This will continue to be the trend, and
while a few sprinkles are possible through midnight or so, most
locations, including at the coast, should remain dry.
The remainder of the forecast remains on track with temperatures
expected to fall into the mid to upper 40s inland and the low to
mid 50s nearer to the coast.
&&
.MARINE...
Issued at 1000 PM EST Wed Feb 7 2024
Buoy observations over the Atlantic indicate lingering rough seas
of 7 to 12 feet, despite a gradual downturn in wind speeds. Buoy
41070 is still gusting around 25 kt but the trend will be for
northeast winds to decrease through daybreak Thursday. A Small
Craft Advisory remains in effect for all of the local Atlantic
waters tonight.
&&
.AVIATION...
(00Z TAFS)
Issued at 1000 PM EST Wed Feb 7 2024
VFR continue with very brief periods of MVFR CIGs possible at
coastal terminals, as a low-mid level marine cloud layer brushes
the coast. Winds generally 5-10 kt with gusts around 15 kt,
decreasing into the day Thu. NE winds veer to the east thru Thu.
afternoon around 5-10 kt. Expect FEW-SCT mid level clouds during
the afternoon as well.
&&
.HYDROLOGY...
Issued at 1000 PM EST Wed Feb 7 2024
The St Johns River at Astor is around 2.5 feet and is forecast to
begin a slow decline through Minor Flood Stage into Thursday. The
river is forecast to fall into Action Stage by Thursday night,
where it will remain through late week, before declining further
this weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 50 71 53 74 / 10 0 0 10
MCO 50 74 55 76 / 10 0 0 10
MLB 55 72 58 75 / 20 0 0 10
VRB 56 74 59 76 / 20 0 10 10
LEE 47 74 53 76 / 0 0 0 0
SFB 50 75 53 77 / 10 0 0 10
ORL 50 75 55 76 / 10 0 0 10
FPR 56 74 59 76 / 20 0 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...High Surf Advisory until 10 AM EST Thursday for FLZ141-154-159-
164-347-447-647-747.
AM...Small Craft Advisory until 4 PM EST Thursday for AMZ550-552.
Small Craft Advisory until 4 AM EST Friday for AMZ555-570-572-
575.
&&
$$
UPDATE.......Schaper
LONG TERM....Watson
AVIATION.....Schaper
Area Forecast Discussion
National Weather Service Marquette MI
730 PM EST Wed Feb 7 2024
.KEY MESSAGES...
- Chances for rain increase from west to east on Thursday,
then pcpn gradually transitions to snow this weekend as a low
pressure system tracks northeast through Ontario and cold air
arrives behind the low.
- After the passage of the low, scattered light LES showers will
likely prevail for mainly NW lake effect snow belts this weekend
into early next week.
&&
.UPDATE...
Issued at 730 PM EST Wed Feb 7 2024
Quiet and mild weather continues this evening, with much of the area
still seeing temperatures in the upper 30s and lower 40s. The
exception to this is across the eastern UP, where more breaks in
the cloud cover have allowed a few spots to drop into the lower to
mid 30s. Minor adjustments have been made to the forecast to allow
for greater coverage of sprinkles across the western UP through the
first half of the night. Reflectivity remains weak, and little
appears to be reaching the ground, but satellite is showing another
burst of cooler cloud tops moving northward from NW WI behind the
first round of sprinkles currently moving towards the north-central
UP.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 302 PM EST Wed Feb 7 2024
Water vapor imagery and RAP analysis show an amplified pattern
across the U.S., featuring a trof over the western U.S. and a ridge
from the western Gulf of Mexico into se Canada. In the resulting sw
flow into the Upper Great Lakes today, it`s another warm day for
Upper MI, especially across the w. Temps at some locations have
risen to around 50F there despite plenty of high cloudiness. With
southerly sfc winds off of Lake MI, it`s cooler to the e with temps
generally 35-40F. To the w and sw of Upper MI, a band of radar
returns is showing up from northern MN to WI. So far, based on obs,
not much more than sct sprinkles are reaching the ground.
The aforementioned band of radar returns corresponds with a band of
moist isentropic ascent around the 300k sfc (roughly 700-750mb).
That ascent continues to sweep ne this evening. The antecedent dry
low levels need to be overcome, but given the few obs of sprinkles
upstream, opted to carry a mention of sprinkles lifting across the
western counties btwn 22-04z. Potential of sprinkles won`t last more
than 2-3hrs at any location. Outside of that, expect a dry night.
Upslope sse sfc flow off of Lake MI is supportive of fog
redevelopment tonight into central Upper MI. However, much more wind
thru the lower levels compared to recent nights in addition to high
cloudiness will limit radiational cooling that would make dense fog
more likely. Thus, not anticipating any dense fog development. Will
be yet another unseasonably warm night, something that has been
common this winter. Expect min temps in the mid to upper 30s F. A
few spots may slip to 32F.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 337 PM EST Wed Feb 7 2024
Thursday, a 500mb trough will be over much of the Great Plains
including a closed low segment straddling the North Dakota/Canada
border. This will support a 12Z GEFS mean 989mb surface low
over the ND/MN state line that will pass along the northern
shores of Lake Superior through midday Friday. The advancement
of PoPs into the UP has slowed with each forecast package and
this one is no exception, with 12Z HREF probabilities of
measurable precipitation remaining below 20% until after 18Z
Thursday. The rain that does arrive will be light, with the HREF
maximum QPF through Friday morning being between a tenth and a
half inch, with the mean being around a quarter inch. The rain
will also be scattered in nature until around 18Z according to
HREF reflectivity paintball plots. Then, HREF members are
consistent with a line of showers passing through until 00Z when
showers become scattered in nature once more. A novelty in the
forecast may be the outside chance of thunder, as the SPC notes
a steep enough lapse rate above the surface inversion to
support some isolated elevated thunderstorms. With soundings
struggling to reach 100 J/kg of MUCAPE, thunder will be left out
of this forecast package, but it is not completely out of the
realm of possibility that a lightning strike or two may be seen
or some thunder heard over the UP.
Once the cold front swings through the area Friday, rain will
transition to snow as surface temperatures widespread fall below
freezing by Friday night. Synoptic precip will be limited to any
wraparound moisture, but also arriving with the cold front will be
strong cold advection aloft, enough to drive the lake surface to
850mb temperature gradients to -15 C by midday Saturday. Nearly
every member of the Grand Ensemble keeps a supportive thermodynamic
profile for lake effect snowshowers over the UP through early Monday
morning, when shortwave ridging will put a damper on the showers.
PWATs below a quarter inch should contribute to the lake effect snow
totals being mostly low-impact, though confidence is low at
mesoscale-driven showers at Day 3+ timeframes.
Beyond Monday, uncertainty grows significantly as ensemble spread
grows. However, cluster analysis gives us a hint of the pattern to
come as generally speaking, the CONUS looks highly likely to settle
into a ridging over the west and troughing over the east pattern.
This will put the UP under northwesterly flow, cooling off the UP,
but only to near-normal temperatures, per ECMWF weeklies and CFS
temperature anomalies. This will also favor periodic weak clipper
shortwaves transiting the Upper Great Lakes, for example, the 12Z
GFS shows such troughs passing through on a nearly daily basis next
week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 616 PM EST Wed Feb 7 2024
VFR will prevail at all terminals through the evening, and likely at
IWD and CMX the rest of the night. At SAW, upslope southerly winds
will likely bring a return of LIFR conditions tonight - likely an
LIFR stratus deck with vis only falling back to MVFR. CMX may see
MVFR 3-5SM vis in BR during tonight as well. LLWS develops at
IWD/CMX tonight, continuing into Thu morning. After an improvement
to VFR at SAW by late morning, VFR ceilings lower to MVFR at all
terminals into the evening while rain chances move in.
&&
.MARINE...
Issued at 337 PM EST Wed Feb 7 2024
20-25 kt southeasterly winds will increase to 25-30 kt through
tonight and Thursday. As a low pressure passes along the northern
shore of Lake Superior through the end of the week, southwesterly
gales to 35 knots are expected over western Lake Superior with an
approximately 20% chance of localized gales to 40 kt Friday between
the Keweenaw Peninsula and Isle Royale. Winds fall below gales early
Saturday morning, veering northwesterly as they fall. Wind gusts
remain above 20 kt until midday Sunday, with no other significant
wind events forecast for the remainder of the forecast period.
During the period of gales Friday, waves will increase to 8-12 feet,
falling below 8 feet early Saturday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Friday morning through late Friday night for
LSZ162-240>244-263-264.
Lake Michigan...
None.
&&
$$
UPDATE...LC
SHORT TERM...Rolfson
LONG TERM...GS
AVIATION...LC
MARINE...GS
Area Forecast Discussion
National Weather Service Salt Lake City UT
401 PM MST Wed Feb 7 2024
.SYNOPSIS...Intermittent wet weather will continue through
Saturday along with a trend towards colder temperatures. Dry
conditions are then likely from the latter half of the weekend
into next week with temperatures slightly below normal.
&&
.SHORT TERM (Through 12Z/5am Friday)......While the inland-
penetrating atmospheric river event from earlier this week has
shifted east of our area, lingering moisture combined with a deep
longwave trough over the western US has led to a wet day across
much of Utah and southwest Wyoming. Precipitation type has been
extremely challenging for valleys of northern Utah; thermal
profiles are marginal for snow to valley floors, but precipitation
intensities are locally pushing snow levels down to valley
floors. This has led to a wide range of snow observations from
nothing to several inches. Roads have remained generally wet,
except for some benches at around 4700` and higher where slush-ups
have been observed on cameras. Areas that have overperformed
include Ogden, Davis/Weber benches, U of U district, and the West
Jordan Bench. Meanwhile, mountain locations throughout the state
have seen healthy totals, especially the southern mountains and
areas favored by southwest flow. Bryce Canyon COOP set a daily
record of 15.5" and automated observations from the upper
elevations of Provo Canyon have suggested snow rates of 2-3" per
hour for multiple consecutive hours! Area radars show a definitive
back edge to the current round of stratiform precipitation,
moving generally west to east and about to reach the I-15 corridor
as of this writing.
Looking forward to tonight and beyond, models depict a weak
shortwave trough exiting the area late this afternoon while a
closed low forms over the southern Great Basin tonight and pushes
eastward along the UT/AZ border through tomorrow night, bringing
synoptic ascent to southern and central Utah. For northern Utah
and southwest Wyoming, it is difficult to pinpoint defined areas
of synoptic forcing for the next 24-48 hours as the region lies
under general cyclonic flow. Thus, forecast confidence varies
significantly across the forecast area.
For southern/central Utah, there is high confidence in
significant mountain snow, with HREF ensemble members showing high
likelihood (>70% chance) of exceeding inch/hour snowfall rates
tomorrow and totaling over a foot of snow for the Brian Head
region, Pine Valley Mountains, and other nearby high terrain
extending as far north as the Wasatch Plateau. Valleys will see
lighter accumulations of a few inches, with potential for snow
around the morning commute (especially from Cedar City south to
the upper elevations of I-15 between St George and Cedar City.
Snow will taper off by the afternoon west to east. Winter Storm
Warnings continue for the mountains and Winter Weather Advisory
has been reissued for Bryce Canyon. We will continue to monitor
for any needed alerts for valley areas.
For northern Utah and southwest Wyoming, CAMs continue to suggest
a low-end chance (<30%) of several inches overnight in the
southern Wasatch Front, especially the benches of Utah County.
Global models meanwhile show intermittent precipitation continuing
for much of the night. The current forecast is closer to the most
likely outcome which is a few showers and minimal impacts, but
worth noting a low-end potential for more impactful snow,
especially areas near 5,000 feet and higher such as Nephi. Another
change to northwest flow late in the day may provide a convergence
boundary for another period of more organized light snow by the
evening. Combined with colder temperatures filtering in, there is
some potential (<50%) for valley snow impacts for the evening
commute. All of this will require continued monitoring of high-res
models coming in to hopefully gain better forecast confidence.
Worth noting that global models are generally bullish throughout
the period, and thus the spread in our probabilistic snow products
(which include many global ensembles) is much higher than normal.
Cannot completely discount the higher-end amounts, though CAMs
would strongly suggest that that scenario is unlikely. Ongoing
mountain warnings and advisories continue through 5am tomorrow,
and future shifts will monitor whether any extensions of these are
needed.
.LONG TERM (After 12Z/5am Friday)...The long term period consists
of a closed low exiting to our east on Friday which will keep
some lingering high elevation snow for the central mountains up
through the Uintas. One final wave moves through the Great Basin
Friday evening that could bring more snow all the way down to
valley floors, potentially even in lower Washington county. After
this wave exits Saturday evening we will enter a dry period,
likely through the middle of next week. There is still 40% of
ensemble members that do suggest a trough moving through the
region by midweek, but the other 60% of solutions keep the pattern
dry with a ridge over the west.
The exiting closed low on Friday will keep snow showers going
through the central mountains up through the Uintas that could
deliver a few more inches of high elevation snow through Friday
afternoon. There is one caveat to note, the latest run of the nested
NAM and RAP are advertising a wave that pushes through northern Utah
Friday morning that could deliver several inches of valley snow for
the Friday morning commute, however these are the only guidance
members that are depicting this. The rest of the guidance keeps
conditions dry Friday morning.
Quickly on the heels of the exiting low, a continental airmass will
be moving south from interior Canada on Friday evening. The
associated airmass will bring colder air that will drop snow levels
to all valley floors, potentially even lower Washington county. The
limiting factor with this airmass will be the relatively dry air
associated with it. Flow will turn northerly behind the passage of a
cold front and widespread light snow will develop with an inch or
two of valley accumulation possible along with several more inches
of mountain snow. The exact trajectory of this snow currently looks
to be across central and southern Utah, but northern Utah can`t be
ruled out as ~20% of members keep the wave slightly further east as
it drops south, which would bring light snow to northern Utah.
Conditions begin to dry out on Sunday as a ridge builds out west.
Temperatures will remain a few degrees below normal before a gradual
warming trend through midweek as conditions likely remain dry (60%
chance).
&&
.AVIATION...KSLC...Lower end MVFR to high end IFR conditions are
expected over the KSLC terminal through about 03Z before BKN to OVC
CIGs break to a SCT layer, and area snow showers gradually taper
off. Winds will remain out of a southerly direction, with a 20%
chance of becoming northerly before 01Z. There is a 40% chance that
MVFR CIGs remain in place through the overnight hours. Another area
of showers will push into the airfield around 12Z tomorrow morning,
with a 30-40% chance of bringing MVFR VIS to the airfield.
.REST OF UTAH AND SOUTHWEST WYOMING...Widespread MVFR to IFR
conditions with localized LIFR conditions are expected through the
next 24 hours as a storm system impacts the region. Snowfall along
the I-15 corridor will gradually ease up through the evening,
leaving mostly low level cloud cover. A few lingering snow showers
are expected over West-Central Utah overnight, and will push into
the Wasatch Front by early morning (10-12Z). Another area of
widespread rain/ snow will push into southern and central Utah
tomorrow morning, bringing widespread MVFR to IFR conditions, with
localized LIFR conditions in heavier precipitation.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory until 5 AM MST Thursday for UTZ110.
Winter Storm Warning until 5 AM MST Thursday for UTZ111-112.
Winter Storm Warning until 5 AM MST Friday for UTZ113-117-125.
Winter Weather Advisory until 5 PM MST Thursday for UTZ127.
WY...None.
&&
$$
Van Cleave/Mahan/Webber
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity