Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/09/24
Area Forecast Discussion
National Weather Service Bismarck ND
940 PM CST Fri Mar 8 2024
.KEY MESSAGES...
- Patchy fog is possible tonight across the northwest and north
central, especially in the vicinity of the Turtle Mountains
and Devil`s Lake Basin.
- Wide variation in temperatures Saturday with cool highs north
and where there is still snowpack to seasonably mild south,
especially areas that are snow free.
- A more substantial warmup will bring above average
temperatures Sunday and into next week, although the deeper
snowpack far north could limit the warmup.
- Dry weather is expected through early next week, with low
chances for precipitation starting midweek.
&&
.UPDATE...
Issued at 940 PM CST Fri Mar 8 2024
Minimal updates needed late this evening. Hi-res models have
backed off on the southern expansion for fog, although maintain
the possibility of fog in the north central and northwest,
mainly the Highway 2 corridor and north. Have made some slight
adjustments to patchy fog mention as a result, although the
forecast overall remains on track.
.UPDATE...
Issued at 540 PM CST Fri Mar 8 2024
Limited updates needed at this time. Mostly clear skies are
currently being found across the area. The RAP remains
aggressive in fog coverage for tonight, while most other hi-
res vis models keep the potential in the north. For now left the
forecast as is, with minor adjustments to include widespread clear
wording in cloud cover.
&&
.DISCUSSION...
Issued at 207 PM CST Fri Mar 8 2024
Most of the clouds have given way to a sunny sky across western
and central North Dakota. At the upper levels, western and
central North Dakota is under the influence of northwest flow
aloft as a weak shortwave moves off to the east and a ridge
resides to our west.
There will continue to be a wide variation of temperatures
today as much of western and central North Dakota is still
seeing observed snowpack. The exception is generally across the
southern third of the state, where there is plenty of bare
ground and the snowpack is spottier. Temperatures across the
north and where there is still substantial snowpack will max out
this afternoon only in the lower 20s to lower 30s. Further
south and where snowpack is struggling to hang on, highs will
range from the mid 30s to mid 40s. For areas with two inches of
snow or greater, we trended towards the NBM 10th percentile for
highs. For areas with less than two inches of snow, we trended
towards the NBM 75th percentile.
Tonight will see light and variable winds with an occasional
southerly component. Many of the CAMs suggest that we could see
some patchy fog overnight and into Saturday morning. The
consensus seems to keep these lower visibilities confined to the
north central and in the vicinity of the Turtle Mountains and
Devil`s Lake Basin. However, the RAP is starting to come in more
aggressive, spreading fog further south and west, covering much
of central North Dakota. For now, we will keep mention confined
to the north central.
The ridge nudges closer overnight and on Saturday, before the
axis moves across the state Saturday night. This will mean
warmer temperatures on Saturday, but with a similar variation
because of the lingering snowpack. For this reason, we decided
to use the same methodology for highs today. Saturday`s highs
should range from the mid 20s to mid 30s north, with
temperatures mainly in the upper 30s to upper 40s south central
and southeast. Southwest will see the warmest temperatures,
where we could see highs well into the 50s.
For the rest of the weekend and into the first part of next week,
the flow stays progressive and dry with the ridge flattening
and popping back up periodically as a couple weak shortwaves
move through well to the north of the International Border.
This pattern will bring even more warmth to end the weekend to
and start next week, even though areas that hang onto lingering
snowpack may remain on the cooler side. Sunday`s highs will
range from the upper 30s and lower 40s northeast to the upper
50s southwest. Monday then looks like the warmest day of the
period, when we see some lower 60s return to the forecast across
the far southwest and south central.
Models and ensembles suggest that a broad longwave trough will
move somewhere into the central US by mid to late week,
potentially leading to some more active weather and a return of
low to medium precipitation chances. Temperatures may also cool
down just a bit. For now, cluster analysis suggests that most
scenarios will keep the bulk of the precipitation well to our
south, but quite a bit can still change around a week out.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 540 PM CST Fri Mar 8 2024
VFR conditions are generally expected at all major TAF sites
through the forecast period. Some patchy fog will be possible
in the vicinity of the Turtle Mountains tonight into Saturday
morning. While the fog looks to be fairly localized at the
moment, there is a nonzero chance it could spread west and south
near KXWA, KMOT, KBIS, and KJMS before it lifts. Have not
included the mention at this time for any of the major sites due
to the high uncertainty. Westerly winds will become light and
variable tonight, then become a light south to southeast wind on
Saturday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Anglin
DISCUSSION...ZH
AVIATION...Anglin
Area Forecast Discussion
National Weather Service Columbia SC
922 PM EST Fri Mar 8 2024
.SYNOPSIS...
There will be a threat for localized flooding along with severe
thunderstorms, mainly Saturday afternoon. A cool, dry air mass
will move in behind the system for Sunday and Monday, followed
by a warming trend into the middle of next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Atmospheric moisture increases tonight with PWAT values at
their climatological maxima by morning. Isentropic lift
strengthens through the evening and overnight, leading to rain
moving into the region before midnight. As a warm front lifts
northward into the forecast area this morning, convergence will
enhance convection leading to a band of heavy rain and possibly
elevated thunderstorms. This will increase the flash flooding
potential early Saturday morning, particularly in urban areas
and near small streams. The area of highest risk at this point
appears to be the greater Augusta area and the CSRA. Therefore,
we have issued a Flood Watch for that area. Rainfall amounts
should generally range from 2 to 3 inches in the CSRA. The
probability matched mean QPF values from the HREF suggest that
localized amounts of 3 to 5 inches will be possible as well.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
By Saturday morning, the heavy band of showers and thunderstorms
will be crossing the area. The trends in the HRRR and HREF guidance
have steadily sped this line up, in association with keeping
the warm front confined to the extreme southern portion of our
forecast area through early Saturday. The NAM and hi-res NAM
are the only members of the suite that push the warm front north
of I-20 by Saturday morning, and even further north than the
global ensembles guidance. While the southeastward cold pool
propagation is likely overdone in the many of the HREF members,
the NAM and global is also likely overdone. So thinking that the
area of heaviest qpf will generally lie along and just south of
the warm front, so a swath from the Augusta metro across
through Clarendon county will likely see the highest precip
totals; a very narrow band of qpf over 3"+ inches is likely
across parts of the swath with a general 1-2" south of I-20.
Given the diurnal timing and that the warm front will remain
consolidated across the extreme southern forecast area, the
severe threat is decreasing with this event. A lack of surface
based instability will line up with the strongest moisture
convergence and synoptic forcing in the morning. The majority of
the hi- res guidance does eventually pull the warm front north
by late Saturday morning and afternoon, along with developing
some surface based convection (SB CAPE > 500 J/kg). However, the
weakening surface convergence, lack of synoptic lift, and dry
air intrusion aloft will greatly limit severe potential. So
overall, the primary threat is flash flooding and this threat is
mainly focused south of I-20; the severe threat has decreased
somewhat but isolated damaging winds are possible, again across
I-20 and south. Not to be forgotten are the gradient winds with
this developing low; wind gusts within the warm sector and close
to the triple point will gust to around 30mph, higher
confidence across the coastal plain and southern Midlands.
Strong cool and dry advection will push into the area by
Saturday afternoon leading to cooler night with temps falling
into the 40`s and dew points will into the 30`s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Very little change in the thinking for the long term pattern as
a very quiet weather is anticipated thanks to deep high
pressure steadily building into the eastern US. The upper
trough associated with the rain and storms on Saturday moves
over the region Sunday into Monday, bringing some cold air
advection to the area. The cold air advection and lower heights
are forecast to keep highs a bit below average for this time of
year and overnight lows Sunday night and Monday night on the
colder side, with some moderate potential (30-50%) for some
locations to get near the freezing mark each night, particularly
Sunday into Monday; given that we are in the growing season now,
a frost advisory will possibly be needed. A warming trend then
returns for mid to late week as upper ridging is forecast to
move over the area. The next chance of rain looks to be at the
end of the week ahead.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Pressure ridge extending into the area from the Mid Atlantic.
Low pressure system developing along the Gulf coast will track
northeast across the region late tonight into Saturday morning.
Ceilings are currently VFR over central SC with widespread
strato-cumulus. Ceilings are lowering across east central Ga to
MVFR. High probability of the ceilings lowering in advance of
the low pressure system. Expect widespread IFR conditions after
06z as widespread rain overspreads the area. Visibility likely
to be reduced in heavier rain toward 12z Saturday into the
morning. Strong convection possible in the afternoon with brief
restrictions but expect ceilings to improve after 18z. Winds
will be east-southeast 10 knots with higher gusts overnight
shifting to southwest by early Saturday afternoon with gusts to
near 20 knots.
EXTENDED AVIATION OUTLOOK...Ceiling restrictions possible into
Saturday evening. No significant impacts Sunday through
Wednesday.
&&
.HYDROLOGY...
Wednesday`s heavy rainfall has led to high flows along with some
minor to moderate flooding along the Congaree River downstream
from Columbia. Another round of rainfall tonight and Saturday
will likely lead to additional rises, along with additional
rivers reaching flood stage.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Flood Watch from 2 AM EST Saturday through Saturday afternoon
for SCZ030-035-041-135>137.
GA...Flood Watch from 2 AM EST Saturday through Saturday afternoon
for GAZ063>065-077.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
HYDROLOGY...
Area Forecast Discussion
National Weather Service Indianapolis IN
1001 PM EST Fri Mar 8 2024
.KEY MESSAGES...
- Rain showers will continue at times through tonight with a few
non-severe thunderstorms as well. Brief heavy rainfall is
possible.
- Rain/Snow showers with minor snow accumulations possible
Saturday Night
- Above normal temperatures return for next week
&&
.FORECAST UPDATE...
Issued at 1000 PM EST Fri Mar 8 2024
The band of moderate to locally heavy rainfall that impacted a
narrow portion of eastern counties early this evening has weakened
and mainly exited the CWA towards the Ohio border. While light to
moderate rainfall rates will continue as this patch exits far eastern
zones late this evening...attention also turns to the region`s
western half.
Rather weak cold front aligned NNE/SSW is currently beginning to
cross Indiana, with westerly winds reported behind its passage along
the Wabash Valley from Benton County down to Vincennes as of 930PM
EST. Modest forcing along this boundary will encourage slight
increase in coverage of so far lighter rain showers currently west
of I-69/US-31. Additional rainfall of up to 0.10-0.25 inches is
possible under moderate rain rates in few stronger showers...
although confidence here is not overly impressive given observations
and downward trend in most recent HRRR output.
Expect at least isolated visibility reductions in fog as cooler air
arrives from west to east...especially where heavier rainfall fell
earlier this evening over eastern/far eastern counties. Despite
antecedent unseasonably high dewpoints in the low to mid-50s,
upstream observations still suggest the somewhat-delayed frontal
zone should lead to a more distinct temperature drop by the predawn
hours over much of the region...with lows by 13z ranging from the
low 40s north/west of Indianapolis to around 50F from Washington to
Greensburg and points south/east.
&&
.SHORT TERM (This evening through Saturday)...
Issued at 255 PM EST Fri Mar 8 2024
Synopsis:
Surface analysis early this afternoon shows low pressure in place
over Central IL. A warm front extended northeast from the low,
stretching across NE IL to northern Indiana and northwest OH.
Central Indiana was within the warm sector with south to southeast
surface flow in place. Radar shows a large swath of rain over
Indiana, with some clearing found across southern IL and western KY
working northeast toward Central Indiana. Aloft, an upper trough was
found over the western plains, resulting in southwesterly flow in
place aloft across Indiana and the Ohio Valley. Water vapor
continues to show abundant moisture available ahead of the trough.
Tonight...
Models suggest broad isentropic lift will remain in place tonight as
the upper trough axis over the plains advances toward Central
Indiana. The surface low over IL is expected to continue to push
toward Michigan, and eventually begin to drag a cold front across
Central Indiana during the overnight hours. As this occurs, the
models suggest that the isentropic lift is lost and the best
moisture shifts eastward as specific humidities fall to 4 g/kg by
12Z with a drying trend indicated by subsidence. Forecast soundings
continue to show a nearly saturated column through the evening hours
with pwats still near 0.9 inches. In previous discussions, heavier
rains tonight were of a concern as a LLJ was expected to be over KY
and pushing into Indiana overnight. Regarding this, the newest runs
suggest this LLJ has shifted farther east, over OH. This will impact
our forecast amounts with lesser amounts of of rainfall expected
than previously. However, confidence still remains high for rain
tonight as adequate forcing and moisture still remains in place.
Radar trends across the area suggest a dry slot over SE MO/WRN KY
and SRN IL pushing northeast toward Central Indiana, although some
development is noted along and near the frontal boundary in south
central MO.
HRRR continues to suggest widespread light rain across Central
Indiana this evening. DESI Ensemble members also agree to widespread
rain across Central Indiana this evening. Thus will trend pops
toward 100 again during the evening hours, for generally lighter
precipitation amounts than earlier forecast.
Late overnight as the front begins to pass and isentropic lift is
lost and pops will need to be set on a decreasing trend from west
toward the east. As cold air advection begins lows will begin to
fall to the lower to middle 40s for lows.
Saturday...
Models show the upper trough axis pushing east across Indiana
through the course of the day. The axis will reach points east of
Indiana by mid to late afternoon. As mentioned earlier, isentropic
lift will be lost in the early morning hours across the western
parts of the forecast area and by the later hours of the morning
across the east. This will result in a lack of forcing and
subsidence becoming predominate across our forecast area by the
afternoon hours. HRRR suggests precip will be possible mainly in the
SE areas during the morning hours, but tries to develop some
convective showers in the afternoon. Confidence for this is low as
forecast soundings show subsidence and dry air aloft and limited
instability forcing as a strong inversion is in place aloft. Thus
confidence is high for morning precipitation across the southeast as
forcing departs, but much lower in the afternoon as the HRRR is
suggesting. For now will focus pops mainly across the southeast
parts of the forecast area in the morning hours. Cold air advection
will be in play, limiting a strong temperature rise. Look for highs
in the middle 40s to near 50.
&&
.LONG TERM (Saturday night through Friday)...
Issued at 255 PM EST Fri Mar 8 2024
A significant warming trend is expected to begin this week, with
high temperatures climbing to near 70 by Thursday.
To begin the period, we`ll find ourselves in northwesterly flow
which may become blustery at times. Strong cold air advection,
albeit brief, will allow temperatures to drop below freezing
Saturday night and Sunday night.
Additionally, enough low-level instability may be present for
scattered snow showers Saturday evening/night. RAP/HRRR/NAM show
between 25 to 50 J/kg SBCAPE, which is sufficient for snow showers
under cold upper-level troughs. The only caveat is moisture
availability. In this case, model soundings show saturation below
750mb so this may not be too much of a problem. Furthermore, a
shortwave trough diving out of Canada may allow for some broader
lift which may aid in snow shower development. Most of the activity
is expected to be light...flurries at best, but a few heavier bursts
of snow are not out of the question.
After that, surface high pressure arrives Sunday and quickly moves
off to the east. Lingering northwesterly winds diminish rapidly
Sunday evening leaving us with clear skies and calm conditions as we
head into Monday. Clear skies and calm winds this time of year after
recent rainfall raises the question of fog development. Most
guidance shows a very dry column, but some of the higher-res
guidance have RH above 90 percent by Monday morning. Widespread fog
doesn`t appear likely...but some isolated instances of patchy ground
fog are possible. Additionally, frost formation appears likely
Monday morning.
Despite the cold and potentially frosty start, Monday begins our big
warm up as ridging builds just to our west. Return flow on the back
side of the departing surface high will lead to southerly winds
through much of the coming week. Readings in the upper 50s to near
60 are possible Monday, then mid 60s Tuesday and finally upper 60s
Wednesday. Temperatures near 70 are in play, but influence from
broad troughing over the Pacific Northwest may throw a wrench in
things.
A few shortwaves look to eject out of the parent trough mid week,
leading to rain chances beginning Wednesday. Rain chances continue
on and off through the remainder of the period as troughing remains
to our west. Low-level moisture looks to gradually build in from the
south as well, with greatest rain chances towards the end of the
week.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 639 PM EST Fri Mar 8 2024
Impacts:
- Widespread SHRA this evening...tapering off west to east pre-dawn
- Ceilings deteriorating to IFR by 7z tonight...improving thru MVFR
Saturday afternoon; CIGs to bounce between categories this evening
- Visibility in VFR/MVFR dropping to MVFR at times in RA/BR thru 7z
- Frontal passage through middle of overnight to veer winds to
westerly by 06Z...sustained at 7-10KT through 09Z...increasing SAT
Discussion:
Rain with embedded stronger showers will increase in coverage this
evening, although low confidence in any downpours over any
individual terminal. Ceilings will vary, with VFR possible at times
over KLAF/KHUF through 3z...MVFR expected to prevail over all TAF
sites by late evening...and mainly IFR expected to arrive from NW to
SE by 7z. CIGs to slowly improve to low MVFR by early afternoon
Saturday.
Expect visibility to be mainly VFR/MVFR with steadier rain and/or
subsequent mist promoting MVFR. Winds from the SSE around 00z will
veer this evening...first slowly through southerly directions ahead
of an approaching cold front...and then quickly to westerly by 06z
behind the boundary. Surface flow sustained around 7-10KT this
evening may diminish slightly behind the front...before increasing
to 9-12KT from the NNW by 12z. Northwest flow Saturday will gust to
around 20KT at times.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...AGM
SHORT TERM...Puma
LONG TERM...Eckhoff
AVIATION...AGM
Area Forecast Discussion
National Weather Service Key West FL
1019 PM EST Fri Mar 8 2024
...New DISCUSSION, MARINE, AVIATION...
.DISCUSSION...
Issued at 1019 PM EST Fri Mar 8 2024
All is quiet once again across the Florida Keys. Ridging aloft is
slowly shifting eastward in response to an upper level trough
driving a cold front through the north Gulf coast and southeast
U.S. In the lower levels, we remain on the western periphery of
the ridge that is also being shunted eastward in advance of the
aforementioned front. This has been leading to a gradually
increase in winds across the island chain and surrounding coastal
waters. Currently see all marine observation platforms registering
10 to 15 knots from the southeast. Meanwhile, high level cirrus
continues to stream in overhead due to upper level ridge. Some low
level moisture in the form of clouds could be seen on infrared
satellite imagery prior to the cirrus moving in overhead.
Temperatures are in the upper 70s with dew points in the mid 70s,
making it quite muggy!
For the overnight, we expect winds to continue to increase,
especially across the eastern waters. There is some uncertainty as
to how strong winds will get overnight. The HRRR was the most
aggressive showing a swath of 15 to 20 knots moving across the
waters east of the Seven Mile Bridge. This may possibly be
supported by a ship observation passing through the central
Straits of Florida over an hour ago that registered a wind gust of
20 knots. While it remains to be seen if we will get enough
coverage of 15 to 20 knots, have at least upped winds a tad in the
coastals for the overnight. Otherwise, dry air noted above 850 mb
in combination with the deep layer ridging and a notable
subsidence inversion centered near 700 mb, should shutdown any
precipitation chances and therefore we can continue with near nil.
&&
.MARINE...
Issued at 1019 PM EST Fri Mar 8 2024
A Small Craft Exercise Caution headline in effect for the Straits
of Florida for increasing winds overnight. Otherwise, generally
expecting gentle to moderate breezes to continue overnight, then
weaken by Saturday afternoon. Breezes will veer from south to west
Saturday night and Sunday, then a weak cold front will bring
gentle to moderate northwest to north breezes into the Keys waters
Sunday night. Moderate to fresh northeast to east breezes return
early next week as high pressure slowly moves eastward across the
Southeastern states.
&&
.AVIATION...
(00Z TAFS)
Issued at 1019 PM EST Fri Mar 8 2024
VFR conditions will prevail with dense cirrus at times streaming
overhead. Southeast winds will prevail and gradually become more
southerly through the day on Saturday. At this time, not
expecting a crosswind magnitude to exceed 15 knots.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...LIW
Aviation/Nowcasts....LIW
Data Acquisition.....JAM
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Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
547 PM CST Fri Mar 8 2024
.KEY MESSAGES...
- Precip may end as a little snow across northern IL late
tonight. No accumulations.
- Isolated to scattered rain/snow showers expected on Saturday,
mainly during the afternoon and evening.
- Warming trend begins Monday with above average temperatures
through midweek.
- Active weather pattern returns towards the later part of next
week.
&&
.DISCUSSION...
Issued at 203 PM CST Fri Mar 8 2024
Through Saturday Night:
Steady, mainly light rain with hourly rates under one quarter
inch per hour will continue this afternoon and into the
evening. Beginning to see the development of a few more
convective elements embedded within the stratiform rain shield
across central Illinois. These will pivot northward through this
afternoon and look to focus in the vicinity of the I-55/57
corridors where isolated additional rainfall amounts near an
inch or so will be possible.
Dewpoints are inching up through the mid and even upper 50s in the
vicinity of a northward-moving warm front which will stall in
the vicinity of a Pontiac to Valparaiso line later this
afternoon. Recent objective analysis indicates that 0-3 km
MLCAPE on the order of 50 J/kg is developing within the vicinity
of this boundary. Dense overcast and persistent showers will,
however, inhibit low-level lapse rates from steepening
significantly. That said, noting a subtle uptick in the
convective "look" to cells pushing into NWS Lincoln`s area, and
with decent clockwise turning in the lowest 1 km, it`s not
surprising to see hints at very modest low-level rotation in
these. While we expect that low-level static stability will
probably remain too high for surface-based inflow given the
dense overcast, we`ll keep an eye on these cells as they meander
across areas SE of a Pontiac to Rensselaer line later this
afternoon as brief tornado spin-ups have occurred in less
favorable environments.
The main precip shield will pull away this evening and overnight.
Before it does, the mid-level deformation axis may keep precip
lingering a bit deeper into the overnight hours across far
northern and northwest Illinois. As the column cools, there is
some potential for lingering precip to mix with or even change
to a little snow after midnight, although this window will be
extremely brief with no accumulations given above-freezing air
temperatures. Finally, favorable set up for at least
intermittent/spotty drizzle for locales roughly south of I-80 late
tonight.
The main conundrum for tomorrow is whether enough low-level
moisture will remain in place for the development of diurnally-
driven rain and snow showers. An intense vort max--currently
diving out of southern Manitoba--is forecast to amplify as it
digs southeastward across our region during the day. While most
global guidance produces no precipitation, the HRRR and RAP
remain steadfast in the development of sufficient low-level
instability to drive scattered convective showers. If these
materialize, wetbulb zero heights falling to near 1000 feet
support a rain/snow mix, or even all snow, in the most robust
convective elements even with air temperatures well-above
freezing. Didn`t see a reason to stray from the inherited chance
PoPs for tomorrow given the robust nature of the incoming vort
max. If trends continue, a further increase in PoPs could be
justified. Regardless, no accumulations are expected given the
well above-freezing conditions.
Activity will diminish through Saturday evening. As colder air
spills down the lake, there is some potential for lake effect snow
shower development, focusing predominantly into Porter but also
perhaps parts of Lake and Jasper/Newton counties. While not off
the charts by any means, lake parameters would be sufficient, with
ELs briefly nearing 8-9 kft and lake-induced CAPE around 100-150
J/kg. Have increase LES pops just a bit Saturday night as a
result, with some very minor slushy accumulations not out of the
question away from the lakefront.
Carlaw
Sunday through Friday:
The upper low that is forecast to bring us a chance of showers
on Saturday (see short term discussion above for details) is
expected to be exiting the area during the day on Sunday. This
means that dry and sunny conditions will make a return to the
area, but the continued northwest winds will keep temperatures
seasonable with highs in the 40s and lows Sunday night in the
upper 20s and lower 30s. However, upper-level ridging will begin
to build into the Great Lakes late Sunday into Monday which
will shift winds out of the south and begin to advect in warmer
air. As a result temperatures are expected to warm through the
middle of next week with highs in the 60s each afternoon and
overnight lows in the 40s.
While the above normal temperatures are forecast to persist
into Thursday, the dry weather looks to be rather short lived.
The reason is a broad upper trough is forecast to dig across
western CONUS heading into Wednesday which guidance suggests
will force several disturbances towards the Great Lakes and Ohio
River Valley through the end of next week. Details on exact
timing and intensity of these waves remains fluid at this time,
but there is a good signal that rain chances (and perhaps even
some thunderstorm chances on Thursday) should return to the area
for the later half of the week.
Looking beyond this system, guidance is starting to develop a
signal that a cooler and more active pattern may develop heading
into the second week of March which could yield periods of
wintry weather if this trend continues. Obviously confidence on
this pattern change is still somewhat low, but something we will
be keeping an eye on going forward.
Yack
&&
.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 545 PM CST Fri Mar 8 2024
- Rain continues this evening with associated vsby/cig
reductions (lowest at ORD/MDW/GYY)
- Breezy NNE winds turn NNW this evening in the 12-15kt range
with gusts to 20-25kt at times.
- Period of rain and snow showers Saturday afternoon (30% chance)
Widespread rain continues early this evening across the area.
Cloud bases have been lowest near the lake, with 400-500ft
observed at ORD/MDW/GYY and IFR to MVFR further west at DPA and
RFD respectively. Expect IFR cigs at all terminals for much of
the overnight hours as the rain begins to taper, perhaps at
times transitioning to more of a drizzle. A return to MVFR
likely occurs toward daybreak Saturday, earliest at RFD and
latest at GYY as the system exits to the east.
Winds will increase out of the ENE early this evening as they
gradually turn N and then WNW as the surface low shifts to the
east. Speeds will increase steadily to 12-15 kt sustained with
some gusts to 20-25kt are possible at times late this evening.
Speeds as well as gusts should ease some by Saturday morning.
There remains a signal for widely scattered gusty rain and snow
showers to develop sometime mid afternoon Saturday that could
then persist into early evening. The PROB30 group covers this
well but did tack on SN as well as extend the time through 2Z
for the 30-hr TAF sites. No snow accumulation is expected.
Winds could become gusty again in the afternoon, especially in
and near any showers that develop.
Petr
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 10 AM CDT Sunday for the IL
nearshore waters.
Small Craft Advisory from 9 PM CST this evening to 10 PM CDT
Sunday for the IN nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Marquette MI
526 PM EST Fri Mar 8 2024
.KEY MESSAGES...
- Light snow, mixed with rain, to brush areas mainly from
Menominee to Grand Marais eastward tonight. Light lake effect
snow showers, not much more than flurries, will develop toward
sunrise west to north central.
- A period of lake effect snow Saturday into Sunday brings a few
inches of snow to the north wind snow belts, mainly over the
east half of the U.P.
- Strong north to northwest winds expected Saturday and Sunday.
Winds may approach 35 mph, particularly east and near Lake
Superior.
- Cooler air builds in this weekend, bringing high temperatures
closer to normal for early March. Well above normal temperatures
return early next week though.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 332 PM EST Fri Mar 8 2024
Water vapor imagery and RAP analysis show mid-level troffing from
central Canada across the Plains to the Southern Rockies. Flow in
the trof is split. Northern stream has 2 waves, one over Manitoba
and the other moving over southern Hudson Bay. In the southern
stream, several shortwaves are noted from the Southern Rockies to
the Mid-Mississippi Valley. With the Mid-Mississippi Valley wave,
sfc low pres is beginning to organize over central IL, and radar
imagery shows an associated wide shield of pcpn over eastern
IA/IL/se WI into Lwr MI and IN. This pcpn is nearly to Green Bay.
Closer to home, a narrow band of -ra/sprinkles lifted across
portions of the eastern fcst area this morning. Otherwise, it`s been
a dry day with considerable high cloudiness. Lake aided stratocu
developed into far western Upper MI this morning under convergent
low-level northerly flow. Some of this cloudiness still lingers, but
coverage has diminished. Current temps range from around 30F in
Keweenaw County to the low/mid 40s s central and e.
As Mid-Mississippi Valley wave lifts ne tonight with associated sfc
low tracking toward Lake Huron, the nw edge of of the isentropic
ascent regime around 700mb will brush areas from Menominee County ne
across the eastern fcst area. Thus, expect a mix of light rain/snow
in that area, though pcpn will likely be predominantly snow for most
of the time. Any snow accumulation will be less than 1 inch.
Increasingly cyclonic low-level northerly flow late tonight will
support a westward development of -sn across Alger County, but
conditions won`t quite be supportive of lake enhancement as lake
850mb delta-t won`t reach 8C by 12z. Farther w, pocket of colder air
(850mb temps down to around -11C over western Lake Superior) should
lead to some lake effect flurries/-shsn developing toward sunrise.
Low temps will range from the upper teens interior w to around
30F e.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 424 PM EST Fri Mar 8 2024
The extended forecast begins with a trough digging into the Upper
Great Lakes yielding a surge of colder air. This will bring near
normal temps and some LES this weekend. The LES diminishes Sunday
morning as ridging builds in. A dry period with warmer than normal
temps follows until the middle of next week when model guidance
begins to diverge. As the mid level ridge continues eastward Tuesday
and Wednesday, a shortwave trough/frontal system quickly pushes
eastward off the Rockies, passing over the Upper Great Lakes Tuesday
night into Wednesday. Another low pressure system looks to follow
behind it late next week, tracking to the south of our CWA. Overall,
not much precip is expected in the U.P. next week.
Starting with Saturday, a trough over northwestern Ontario will dig
southeast into the Upper Great Lakes. This cold air intrusion will
support LES over the north wind snow belts as Lake Superior sfc
temps are around 2-3C and 850mb temps drop to around -8 to -12C;
coldest temps are expected over the north/east portions of the lake.
Model soundings do not show an ideal thermal profile as inversion
heights mainly stay below 5kft, inhibiting the limited moisture
profile from extending very far into the DGZ. The better set up is
over the eastern U.P. where the deeper moisture, higher inversion
heights and better exposure to the DGZ is located for a longer
period of time going into Saturday night. The other things working
for the east is the longer fetch length over the lake, the better
lake sfc-850mb delta-t, and low level convergence. Overall, this is
not an impressive set up. Low confidence in snow accumulations above
0.5" over the west half of the U.P. Around 0.5-2" is forecast
through early Sunday morning over the east half; a few isolated
spots may get up to 4" in persistent LES bands. The CAA will also
promote increased instability/mixing and with the tightening of the
pressure gradient across the area, should support blustery north
winds gusting to 20-30 mph Saturday and Saturday night. Highest
gusts are expected in the east, with some 35 mph gusts possible
along the Lake Superior shorelines.
LES tapers off early Sunday morning as ridging builds in over the
Great Lakes. This mid level ridge will persist through Tuesday
bringing a couple days of dry weather. Mostly clear skies Sunday
night sets the U.P. up for some good radiational cooling bringing
lows into the mid teens to low 20s save for near the lakeshores
where mid 20s are expected. Increasing WAA and positive height
anomalies will bring temps back to well above normal next week with
highs on Monday in the 40s to mid 50s. Tuesday will see even warmer
temps with most highs in the upper 40s to 50s, low 60s are possible
on Tuesday over the interior west.
A weak, shortwave moving through Tuesday night/Wednesday will yield
some isolated showers at best. Following this system, ensemble
guidance is hinting at a low pressure system for late next week.
Currently there is significant spread in the track of this system,
but with above normal temps, mainly light rain is the favored p-
type.
Overall, not much precip is expected in the U.P. next week as
temps remain well above normal into next weekend. That being said,
there does look to be a trend toward near normal and possibly below
normal temps as we progress into the middle/end of March.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 525 PM EST Fri Mar 8 2024
At all sites, VFR will continue thru this evening. Then,
increasingly colder air moving into the area tonight along with
developing low-level cyclonic flow will lead to developing/expanding
lake effect cloudiness/MVFR cigs at all terminals later in the
night. Northerly winds will become gusty to 20-30kt late tonight
thru Sat at CMX/SAW, strongest at SAW. VFR conditions will redevelop
later Sat afternoon at IWD and CMX.
&&
.MARINE...
Issued at 424 PM EST Fri Mar 8 2024
North winds generally remain below 20 kts the rest of the afternoon.
North winds will increase tonight into Saturday as the pressure
gradient tightens and colder air begins pouring across the lake in
the wake of an exiting low pressure system. Internal probabilistic
guidance suggests around a 40-60% chance for gales across the
eastern third of the lake Saturday through early Sunday morning. The
Gale Watch for zones 266-267 from 18Z Saturday to 18Z Sunday has
been upgraded to a Gale Warning. North winds will die down below
gales Sunday afternoon as surface ridging builds in from the west.
Winds across the lake drop to 20 kts or less Sunday night as the
surface ridge axis moves overhead. These lighter winds look to
continue through the early part of next week as ridging remains the
dominant feature.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Small Craft Advisory from 1 AM Saturday to 2 PM EST Sunday for
LSZ243>245.
Small Craft Advisory from 1 AM EST /midnight CST/ Saturday to
8 AM EST /7 AM CST/ Sunday for LSZ240>242.
Small Craft Advisory until 2 PM EST Sunday for LSZ248.
Small Craft Advisory until 1 PM EST Saturday for LSZ249.
Gale Warning from 1 PM Saturday to 2 PM EST Sunday for
LSZ249>251-266-267.
Small Craft Advisory from 1 AM to 1 PM EST Saturday for LSZ250-
251.
Lake Michigan...
Small Craft Advisory from 1 AM Saturday to 2 PM EST Sunday for
LMZ221-248-250.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Jablonski
AVIATION...07
MARINE...Jablonski
Area Forecast Discussion
National Weather Service Phoenix AZ
450 PM MST Fri Mar 8 2024
.UPDATE...Updated 00z Aviation Discussion...
&&
.SYNOPSIS...
Showers and isolated thunderstorms are favored primarily north and
east of the Phoenix area through the rest of the afternoon into
the evening, with gusty winds and small hail being the primary
impacts. Drier conditions will prevail going through the weekend
with temperatures warming back up near to slightly above normal by
Sunday and persisting into the first part of next week.
&&
.DISCUSSION...
Much quieter conditions are seen around the Valley early this
afternoon compared to this time yesterday with only some CU
development over the south-central Arizona lower deserts thus far.
Visible satellite imagery shows a remnant weak circulation, which
brought some showers to parts of the Valley this morning, now
over Pinal County this afternoon. North of Phoenix across the Rim,
satellite and radar show convection developing with a few showers
and an isolated thunderstorm across parts of northern Maricopa
County and across southern Gila County.
Objective analysis this afternoon shows the Desert Southwest
remaining under a broad troughing pattern with northerly flow aloft
over the region while ridging builds in along the West Coast.
Northerly flow will help steer showers and isolated thunderstorms
off the Rim going through this afternoon, however, the bulk of HREF
members show this activity quickly dissipating as it moves into the
lower elevations. Meanwhile, the last few iterations of the HRRR
have become more aggressive with pushing a gusty outflow into the
Valley from the north with additional shower development potentially
making it into parts of the Phoenix area (best chances to the north)
going into this evening. Can`t rule out an isolated thunderstorm
with CAMs indicating a few hundred J/kg of CAPE. Any thunderstorm
that were to develop may produce small hail and gusty outflow winds,
which may produce some localized areas of blowing dust.
For Saturday, a weak shortwave will dive south into northern Arizona
and will aid in shower development across parts of the Rim over to
the White Mountains and into portions of southern Gila County.
Drier, tranquil weather will then prevail by the latter part of
this weekend as weak ridging shifts eastward into the Southwest.
This will lead to temperatures warming back up near to slightly
above seasonal normals as lower desert highs warm into the upper
70s to low 80s Sunday. An overall quasi-zonal flow pattern will be
favored during the first part of next week with a trough passing
to our north early in the week. Dry conditions will persist during
this time while daytime highs maintain reading in the upper 70s
to low 80s across the lower elevations. Going into the mid to
latter part of next week, ensembles are showing an area of low
pressure cutting off over the Southwest, though cluster analysis
show continued uncertainty in how this pattern will evolve. The
inland trajectory of this low suggested by ensembles would favor
limited moisture for our area with increased winds and cooler
temperatures being the primary sensible weather impacts for our
area.
&&
.AVIATION...Updated at 2345Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT;
The main aviation weather concern this evening will be the
potential for a gusty outflow boundary moving through associated
with shower and isolated thunderstorm activity north of the
terminals. Winds for the next couple of hours will be out of the
west, however, winds with the outflow boundary will likely switch
out of the north at mainly KDVT, KSDL, and KPHX with some gusts
briefly touching 20 kts. With respect to the any SHRA activity
directly affecting the terminals, it remains <30%. Main time
period for outflow impact will be between 02-05z. By late evening,
conditions will be mainly tranquil with mainly easterly winds
prevailing with light speeds aob 8 kts. Based on the majority of
model guidance, winds throughout the day Saturday are likely to
stay out of the east with a low chance (20%) of a west shift. SCT
cloud decks at around 6 kft will prevail through this evening
before becoming FEW at 8-10 kft later this evening and throughout
the day on Saturday.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns under mostly skies are expected
through the TAF period. AT KIPL, winds this evening will gradually
switch out of the west and become variable by the mid to late
morning hours on Saturday. At KBLH, winds will mostly be out of a
northerly direction. Wind speeds will generally be aob 8 kts
throughout the period.
&&
.FIRE WEATHER...
Starting today, the region will undergo a drying and warming
trend lasting through the weekend. With temperatures at or just
below normal today, expect breezy northerly daytime winds across
the Lower CO River Valley along with MinRHs dipping to around 20%.
MinRHs for the eastern districts will remain elevated today at
30-50% with light winds. The weekend will see temperatures rise to
above normal with MinRHs falling to 10-15% over the western
districts starting Saturday to 15-20% over the eastern districts
starting Sunday. The above normal temperatures and dry conditions
are likely to persist through the first half of next week with
overall light winds, but winds are likely to become breezy to
windy late next week as a dry weather system dips southward into
the region.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Smith
AVIATION...Lojero
FIRE WEATHER...Kuhlman
Area Forecast Discussion
National Weather Service Raleigh NC
856 PM EST Fri Mar 8 2024
.SYNOPSIS...
A storm system will cross the region tonight through Saturday night.
Cool high pressure will follow for Sunday and Monday, then a warmer
air mass will arrive Tuesday, lasting much of next work week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 856 PM Friday...
Water vapor imagery this evening depicted a long-wave southern
stream trough extending anomalous moisture from the GOM into the
deep south/southern Appalachians. This enhanced moisture will begin
to migrate into our area overnight as the trough migrates eastward.
Increasing mid-level height falls and isentropic upglide will
promote widespread rain filling in from west to east through sunrise
Saturday morning. However, the heaviest rain associated with a
passing low pressure system will likely hold off until after 12Z
Saturday. Forecast soundings indicate primarily stable conditions
tonight, but some elevated instability may creep into the southern
Piedmont towards sunrise tomorrow. Overall though, expecting
stratiform rain to dominate the rest of tonight through 12Z
Saturday. Overnight lows will drop into the mid 40s (N) to lower 50s
(S).
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 300 PM Friday...
The primary weather maker over the next seven days will come from a
system ranging from the Great Lakes to the Gulf of Mexico. A low
near the Great Lakes Friday night, a cold front will trail to the
southwest, and another wave of low pressure along the front will be
located near the Gulf of Mexico. As the entire system moves
northeast, a warm front should rise from south to north across North
Carolina during the day on Saturday, followed by the cold front
Saturday evening. Widespread showers will occur Saturday, then the
chance for rain will decrease Saturday night.
There is still quite a bit of uncertainty as to how the severe
weather will pan out tomorrow. The 12Z HRRR and 12Z NAM Nest show
two very different scenarios. The HRRR shows the strongest
convection remaining mostly across South Carolina, only narrowly
edging into North Carolina, and the bulk of the showers moving east
by sunset. However, the NAM Nest brings the axis of heaviest radar
reflectivities across much of North Carolina Saturday afternoon,
with another line of storms along the cold front moving through
around 00Z Sunday.
With their afternoon update, SPC has kept only the southern part of
the forecast area in a slight (level 2 of 5) risk for severe
weather, with the primary threat coming from damaging winds with a
secondary threat of an isolated tornado. The marginal (level 1 of 5)
risk has also been trimmed, generally from I-85 to the south with
locations north of the interstate just in a general thunderstorm
category. In addition, WPC still has most of the region under a
slight (level 2 of 4) risk for excessive rainfall. Storm total QPF
(0.75-1.5", which is 18-24 hours worth of rainfall) still remains
less than flash flood guidance for 6 hours (2-5"), so at this time
do not have enough confidence to issue a flood watch anywhere. The
severe weather threat will be conditional on where the axis of
heaviest rain develops, especially considering the differences
between the HRRR and NAM Nest outlined above. While SPC has lowered
the threat of severe weather across our area, it still remains a
possibility at all locations.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 205 PM Friday...
The combination of a rapidly deepening area of low pressure as it
tracks through the Northeast and a moderately strong surface high
over the Southern Plains will result in a tight pressure gradient
over central NC in the post-frontal regime. Early Fri morning the
surface winds will start around 10 to 15 mph and will quickly
increase to 15 to 20 mph with gusts 30 to 35 mph through most of the
day on Sun. Dry downsloping flow through the deeply mixed boundary
layer with flow orthogonal to the mountains will promote rapid
drying behind the front with dew points falling into the teens by
midafternoon. Sufficiently wet soils from the widespread rain of 1
to 2 inches will greatly limit the Fire Weather risk. Afternoon
cumulus bubbling up over the northern Coastal Plain may temper highs
across this area into the low to mid 50s while other locations
should rise into the upper 50s to low 60s.
The remainder of the extended remains dry as surface high pressure
builds through the region with only some weak low-amplitude
disturbances bringing waves of thin high clouds. As the surface high
slips offshore Tues, steady mid-level height rises and increasing
low-level thicknesses will support well above normal temperatures
Wed into Thurs as temperatures rise into the mid/upper 70s and
bottoming out overnight in the mid/upper 40s. The next system to
watch will again be heading into the weekend as a low-amplitude wave
aloft develops an area of low pressure along a stalled front from
the ArkLaTex region up through the lower Ohio Valley. Ensemble
guidance is surprisingly in relatively good agreement given the low
predictability features in play, but have capped PoPs at high chance
for now to see how the forecast trends with subsequent updates.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 725 PM Friday...
Current VFR conditions across the area will deteriorate overnight,
as a storm system moves in from the west and southwest. A trend to
MVFR cigs/vsbys is expected starting around 05z/06z in the west
(INT/GSO) and by around 07z-08z in the east (RDU/RWI/FAY), with a
quick trend to IFR cigs/MVFR vsbys within 2-4 hours after, all with
steady rain moving in W to E. IFR cigs and MVFR vsbys in rain are
expected to persist, with high confidence, across all TAF sites from
around 11z until around 21z, after which time a gradual W to E
ending to rain and improvement back to MVFR is expected very late in
the TAF valid period. An isolated thunderstorm or two is possible
Sat after 16z, mainly at FAY, but most of the storm activity with
this system will slip by to our south, and confidence is not high
enough to include this mention at FAY at this time. Low level wind
shear will be a concern areawide late tonight through much of Sat
morning as a 40-50 kt low level jet tracks across the region, with
the strongest winds aloft over our southeast (FAY). Surface winds
from the E and SE will become predominantly from the SE/S Sat
morning, increasing to 8-15 kt by afternoon with a few sporadic
gusts up to 20 kt possible. Wind will shift to be from the SW and W
late in the period as a cold front crosses the area from 19z to 23z.
Looking beyond 00z Sun, all central NC terminals will trend back to
VFR between 00z and 05z as high pressure begins to spread in from
the W. VFR conditions are likely from Sat night through Wed,
although brisk gusty winds are expected Sun. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...Green
LONG TERM...Swiggett
AVIATION...Hartfield
Area Forecast Discussion
National Weather Service Springfield MO
523 PM CST Fri Mar 8 2024
.KEY MESSAGES...
- Scattered showers and occasional drizzle into tonight. A few
non-severe thunderstorms across south-central Missouri through
dark.
- Cooler this weekend, then quieter and warmer weather returns
for the start of next week.
- Unsettled for the last half of next week with multiple rounds
of showers and thunderstorms across the region.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 228 PM CST Fri Mar 8 2024
Synoptic Scale Pattern and Current Conditions:
Water vapor imagery nicely depicts a long wave trough extending from
Ontario to the Four Corners region. At the surface, low pressure is
tracking east across central Illinois with a cold front trailing
southwest from the low. As of 2 PM, the front had made it into
the Winona and West Plains area.
Along and behind the front, we have seen scattered showers for
much of the morning and afternoon. Additionally, areas of
drizzle have developed along and north of the Ozark Plateau
where upslope flow is occurring.
Conditions behind the front have become blustery thanks to
increasing northerly winds and slowly falling temperatures.
Temperatures range from the upper 40s and lower 50s behind the front
to the lower 60s across far south-central Missouri.
Late this Afternoon and this Evening:
That cold front will continue to push southeast and will clear south-
central Missouri by sunset. Short term models continue to advertise
300-600 J/kg of MUCAPE ahead of the front. This will be enough
for isolated thunderstorm potential, mainly southeast of a
Winona to Branson line. No severe storms will occur given the
meager instability. The threat for thunderstorms will end by
around sunset.
Meanwhile, we do expect scattered showers and areas of drizzle to
persist into the evening. The greatest coverage of drizzle will
again be along and north of the plateau. We may then see more of a
transition to scattered showers across southwest Missouri as we see
a more substantial return to cloud ice after 03Z.
Late Tonight and Early Saturday Morning:
The 500 mb trough axis will swing southeast through the region. The
potential for scattered showers and perhaps some drizzle (where
cloud ice is lacking) will continue. The most likely area for more
organized precipitation will be along and south of the Highway 60
corridor along a 700 mb front.
Some short term models including the last few runs of the RAP and
the 12Z NSSL WRF depict a band of light to briefly moderate
precipitation in association with an area of enhanced
frontogenesis in the 09-16Z time frame. Interestingly,
temperature profiles by this time may be cold enough to support
a rain/snow mix or a transition to all snow. The main area of
focus is between I-49 and Highway 63 along and south of the
Highway 60 corridor.
We currently have 30-50% PoPs in place to cover this potential
banded precipitation scenario. However, confidence is a bit
lower for a transition to snow (20-30%). If we do see the snow,
no accumulations are expected.
Remainder of Saturday:
Precipitation will exit south-central Missouri by midday with skies
clearing from northwest to southeast. The 12Z HREF has most areas
returning to sunny skies by 18Z on Saturday.
Winds will start off rather brisk out of the northwest on Saturday
before diminishing in the afternoon. Despite the sunshine, there is
strong model consensus that highs will only warm into the lower 50s
for most areas. Areas of south-central Missouri will likely warm
into the middle 50s thanks to downslope flow off the plateau.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 228 PM CST Fri Mar 8 2024
Global ensemble scenarios show good consensus that an upper level
ridge will translate east into the upper Mississippi Valley. An
upper level low is also forecast to move east in the Red River
Valley region of Oklahoma and Texas before lifting towards the
Tennessee Valley.
Despite the track of the upper level low, moisture looks very
limited. Thus, we are expecting dry conditions for the period with a
warming trend. We may see elevated fire weather conditions Monday
afternoon as southerly winds increase if finer fuels can dry out
from the recent rainfall.
Highs by Monday will again return into the middle to upper 60s over
most areas. Some locations may warm into the lower 70s if 850 mb
temperatures can warm into the 7-9 C range. NBM 75th percentile
data supports this potential.
Ensemble scenarios then indicate decent agreement that a short wave
trough will move east across the central Plains and into the Ozarks
region from late Tuesday into Wednesday. It should be noted that
there are timing differences. If enough moisture can advect into the
region, there will be some potential for showers and thunderstorms.
We currently have 20-30% PoPs to cover this potential scenario.
Unsettled End to Next Week:
Ensembles show good consensus that upper level short wave energy
will dig southeast across the western U.S. and eventually carve out
a long wave trough. This will put the Missouri Ozarks into a
southwesterly flow aloft with increasing potential for showers and
thunderstorms.
Interestingly, both the CIPS and CSU Machine Learning products
depict 5-15% probabilities for severe thunderstorms in the general
vicinity of the Missouri Ozarks. The potential for severe storms as
well as heavy rainfall will be monitored over the coming days.
Above normal temperatures will persist through Thursday or Friday of
next week. We will likely then see at least a modest cool down by
next weekend as most ensemble members show a cold front passing
through the area.
Five-wave charts do show a fairly deep trough setting up over
roughly the eastern half of the U.S. as we get into late next
weekend. This would support the potential for a frost/freeze
sometime late next weekend or early the following week (March
17th-18th). This is something to keep in mind for anyone
wanting to get an early jump on spring planting.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 520 PM CST Fri Mar 8 2024
For the 00z TAFS, We are expecting MVFR and IFR conditions to
continue tonight into Saturday morning before the clouds break
up on Saturday morning. Some drizzle or light rain will be
possible with the lower ceilings. Gusty winds will develop
around the time of clearing for the afternoon hours Saturday.
&&
.CLIMATE...
Issued at 230 PM CST Wed Mar 6 2024
Record Precipitation:
March 8:
KSGF: 1.58/1908
KJLN: 1.39/1999
KVIH: 0.95/1958
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.
&&
$$
SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Lindenberg
CLIMATE...Schaumann
Area Forecast Discussion
National Weather Service Shreveport LA
1001 PM CST Fri Mar 8 2024
...New UPDATE...
.UPDATE...
Issued at 1001 PM CST Fri Mar 8 2024
The mid-evening sfc analysis indicates our cold front just now
entering the the Wrn sections of E TX into extreme SW AR,
extending from near a MEZ/DEQ, to OSA, to JXI to E of a TYR to JSO
and PSN line as of 0330Z. Scattered convection has increased this
evening near and just behind the front, with the greatest forcing
largely confined along the H925 front and just ahead of a positive
tilt upper trough extending from the Ozarks SW through Cntrl OK
into N TX. The latest mesoanalysis indicated that the air mass
farther E across our region is a bit more stable than farther W
closer to the colder trough axis, but lapse rates are still steep
enough and bulk shear of 60-70kts still strong enough to support
isolated thunder as the convection continues to develop/spread E
over the Nrn half of the area overnight. The short term progs all
vary with the placement and extent of the convection development,
but general agreement exists amongst the 00Z NAM and latest HRRR
that convection may be a bit more scattered than earlier thought
as the trough axis progresses E through the region.
Thus, have increased pops to mid and high chance generally along/N
of I-20 across E TX/NW LA, while also maintaining low
chance/slight chance pops farther S, except dropping mention of
pops across the far SE zones in Cntrl LA. Some residual -SHRA may
linger just beyond 12Z Saturday across portions of SCntrl
AR/NCntrl LA, where slight chance pops persist, but any remaining
-SHRA should diminish as subsidence increases in wake of the
departing trough. Did not make many changes to the forecast min
temps, as increasing cold advection overnight will lead to
falling temps which will continue through even after daybreak
through much of the morning Saturday. Little warming is expected
even through the afternoon as the post-frontal cloud cover will
linger through a better part of the day before diminishing from
NW to SE late.
Zone update already out...grids will be available shortly.
15
&&
.SHORT TERM...
(This evening through Saturday Night)
Issued at 1230 PM CST Fri Mar 8 2024
Still dealing with some sfc based instability and associated
strong storm activity across our far south and southeast zones but
this convection will likely have just about exited our southeast
parishes by the time the forecast becomes valid. Dry-slotting
aloft has allowed for much of the precipitation to come to an end
across our southwest half and this trend should quickly continue
across our northeast half this evening even though the trough axis
remains to our west. CAMS are indicating the possibility of some
redevelopment along the true cold front coming into our western
zones this evening and as the upper trough itself moves ovhd
overnight, cannot rule out some isolated activity continuing
overnight across mainly our far northern zones so held onto some
small pops this evening across our region, ending from the
southwest after midnight and ending early Saturday Morning across
our extreme northeast. Cold front will usher in strong northwest
winds and rapidly falling temperatures overnight but winds speeds
should remain just below Wind Advisory criteria overnight.
Skies will try to clear across our far west and northwest zones
late in the day Saturday and areawide Saturday Night. With the
sfc pressure gradient decoupling, this will allow for winds to
drop off rapidly after sunset on Saturday but the sfc ridge axis
should remain just to our west through sunrise Sunday Morning.
Overnight low temperatures Sat Night will range from the lower 40s
south to near freezing across the foothills of the Ouachitas in
SE OK and SW AR.
13
&&
.LONG TERM...
(Sunday through next Thursday)
Issued at 1230 PM CST Fri Mar 8 2024
In the wake of this current trough, the second piece of the trough
will eject out across our region Sunday Night into Monday with
little if any impacts. In fact, a warming trend will commence
during the day Monday with the aid of returning southerly winds.
That warming trend will continue through the work week but did
have to introduce some small pops Tue Night north of the I-20
Corridor due to a weak shortwave moving quickly across the plains
as there may be enough forcing to generate some precipitation
during this time frame. No surface reflection to this upper
trough, thus the warming trend continues as a much deeper and
significant longwave trough drops south into the southwest Great
Basin Thu into Fri of next week. This system has the potential to
be a big rain maker for us once timing discrepancies work their
way out in the medium range. For now will continue advertising
increasing rain chances beginning late Wednesday and especially
Thu into Fri of next week.
13
&&
.AVIATION...
(00Z TAFS)
Issued at 517 PM CST Fri Mar 8 2024
For the 09/00Z TAFs, a few more showers and storms will be
possible as the frontal boundary moves into our east Texas
airspace this evening. CIGs will return to MVFR levels and
continue through the morning hours, climbing back to VFR during
the afternoon tomorrow, as skies begin to clear by the end of this
forecast period. Variable winds will become northwesterly
areawide by 09/06Z and increase to sustained speeds of 10 to 15
kts with gusts of up to 25 kts possible throughout.
/26/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 49 63 42 66 / 40 10 0 0
MLU 56 63 41 62 / 30 20 0 0
DEQ 44 60 32 64 / 40 10 0 0
TXK 48 60 37 63 / 50 10 0 0
ELD 50 60 37 63 / 40 20 0 0
TYR 46 61 39 64 / 40 10 0 0
GGG 48 62 40 65 / 40 10 0 0
LFK 51 63 42 66 / 30 10 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...15
AVIATION...26