Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/24/23
Area Forecast Discussion
National Weather Service North Platte NE
705 PM CDT Mon Oct 23 2023
.SYNOPSIS...
Issued at 241 PM CDT Mon Oct 23 2023
Key Messages:
- Seasonable temperatures on Tuesday, then slightly warmer Wednesday.
- Potential for showers and embedded thunderstorms Tuesday night/Wednesday
morning and again Wednesday night/Thursday morning across
southeastern areas.
- Low forecast confidence in timing of precipitation, mainly in
the form of light snow Friday night through Sunday. Much colder
air due to arrive by Friday through the weekend.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 241 PM CDT Mon Oct 23 2023
Tonight...An upper trough moving across the Great Basin will form a
cutoff low over Baja Mexico by this evening. A weak cold front will
drop through most of the forecast area. The main concern tonight
will be the development of stratus and patchy fog behind the front.
The latest HRRR, RAP and SREF probabilities indicates fog development
is expected to be across the northwest Sandhills into portions of
the central Sandhills.
Tuesday and Tuesday night...Stratus will slowly erode behind the
weak cold front Tuesday morning. This will limit highs across the
area to the upper 50s to lower 60s across all of the Sandhills, with
65 to 70 far southwest. An upper trough and closed low will deepen
across the Pacific Northwest as an upper ridge remains centered
across the southeastern U.S. Moisture will increase across the
Southern Plains into the Central Plains downstream of a cutoff low
moving into southern New Mexico. This will bring chances for showers
and a few thunderstorms, primarily across the southeastern half of
the area for Tuesday night. Total rainfall amounts up to a tenth of
an inch are forecast across the far southeastern zones, with little
or no rainfall expected elsewhere.
.LONG TERM...(Wednesday through Monday)
Issued at 241 PM CDT Mon Oct 23 2023
Wednesday, Wednesday night into Thursday...Highs have trended up
slightly with near 65 north and the upper 60s to low 70s south. A
closed low ejects from eastern New Mexico into an open trough across
Kansas by daybreak Thursday. This will also draw a cold front into
the area. Another opportunity for showers and embedded thunderstorms
especially across the southeast Wednesday night/Thursday morning as
PWATs increase to 1-1.25 inches across the southeast. If an H7 low
becomes closed off, as shown by the GFS, rainfall amounts will be
higher and would extend further west.
Due to the main upper trough still back across MT and WY Thursday,
the coldest air will still reside across that region. Highs Thursday
are forecast to range from near 40 far northwest Sandhills to the
low to mid 60s far southeast.
Low confidence Friday night through Saturday night regarding timing
and location of light snow. A positively tilted upper trough will
extend from Hudson Bay Canada southwest across the West Coast. This
will bring a good chance for precipitation to WY and SD Friday
night, with a chance into north central Nebraska. Temperatures are
cold enough for snow, with light accumulations favored across the
northwest Sandhills. Chances for snow Saturday through Sunday as the
main upper trough progresses eastward, with the highest chances
Saturday night. Since this will be a strongly positively tilted
upper trough, precipitation chances will quickly lower or end by
Sunday into Monday as drier air works southward from the Northern
Plains, and the main focus becomes located across the Southern Plains
into the Midwest. Higher confidence in temperatures with highs in
the 30s to low 40s Friday and Saturday, and mainly the 30s Sunday
and the mid 30s to low 40s on Monday. Lows in the teens to lower
20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 705 PM CDT Mon Oct 23 2023
Increasing clouds and lowering ceilings are expected throughout the
TAF period as the next shortwave moves into the region. Ceilings
will drop to below 3000 feet by mid-morning for all sites. Winds
remain light, though with gusts under 10 knots.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Kulik
Area Forecast Discussion
National Weather Service New Orleans LA
748 PM CDT Mon Oct 23 2023
...New UPDATE...
.UPDATE...
Issued at 719 PM CDT Mon Oct 23 2023
Performed a gridded update for the next 18-24 hours to pull in the
latest guidance matched with trends. Main focus will clearly be
attention given to fog potential early AM. Did a thorough analysis
into changing conditions and fog probabilities going into daybreak
which reveals a few notes to mention. Observed 12Z KLIX sounding
from this morning compared to the latest HRRR valid 12Z Tue shows
a few changes in the sfc to low-level environment. Namely,
slightly stronger sfc winds due to tightening SLP and an increase
in boundary layer/low-level winds (100-300ft AGL from 5-10kts 12Z
Monday to forecast 15-20kts early Tuesday). Definitely a
noticeable increase in SE flow which will be a factor against
widespread dense fog production, reducing radiational fog
component due to mixing.
However, the complications lie in smoldering marsh fires ongoing
near Bayou Sauvage and Lafitte, blowing/advecting NW. The presence
of smoke nuclei can aid in quick, dense fog production sometimes
zero, or near- zero VIS at times and we saw that with terrible
impacts this morning. Question now lies in how much lingering
smoke can still cause issues for this morning.
HRRR soundings again displays a radiation inversion, albeit not
as deep given mixing for this morning across the Southshore.
Unfortunately, HRRR Vertical Integrated Smoke and Above Ground
Smoke Density is not helping much given the smoldering nature of
the smoke release not being captured distinctly in the models.
Anticipating smoke to still enhance the dense fog potential this
morning but may be more in a plume/corridor stretched NW due to
increase in SE winds. Didn`t get cute on exact location but did
decide to add in smoke along with areas of dense fog generally
across the Southshore, across the lake and into the marshes
getting close to Baton Rouge to Hammond. How far north and west
will remain in question, but be watched closely.
Continuing the message of dense fog/superfog potential and do see
somewhat less of an overall threat given the mentioned conditions
different from yesterday, but don`t want to steer away too far
from the possibility of impacts. Because of that, didn`t change
anything from the current advisory highlights this evening. If
anything, will need to monitor areas to the north with overall
greater <1sm probabilities up to SW MS. Expect more updates as we
continue to closely monitor these conditions overnight and into
early Tuesday.
Otherwise, conditions improve after early/mid morning with another
warm day (or should say hot for this time of the year). Did
include some coastal/marine highlights due to the increase in SW
flow making it breezy over the water today, but should be another
nice day overall. KLG
&&
.SHORT TERM...
(This evening through Tuesday night)
Issued at 325 PM CDT Mon Oct 23 2023
Fog was the problem this morning and remained quite stubborn
through the morning finally completely mixing out shortly after
noon. Multiple things came into play for this as fog develop with
areas of dense fog that mixed with smoke from multiple local marsh
fires the main two in East Orleans and Jefferson parish near
Lafitte. This led to Super Fog which hammered the I-55 corridor
between Ponchatoula and LaPlace where visibilities were near zero
and multiple pile ups occurred. Outside of that conditions
quickly improved with a sunny warm day across the region.
So the main question is, will fog occur again tonight and will it
be as bad as last night. This is not as easy an answer as it
seemed the last few days and even as late as early this morning.
High pressure centered to our NNE will continue to slide east
overnight and off the Mid Atlantic coast by tomorrow afternoon.
Broad low pressure will already be developing along the lee of the
Rockies and this will tighten the pressure gradient over the
region leading to stronger winds. This will help to mix the
atmosphere and thus keep the fog potential down to near zero but
at what point the winds respond is now the bigger question. Winds
were initially expected to ramp up quickly tonight possibly
before midnight, especially just off the deck where h925 winds
would be approaching 20kt but latest guidance is now a little
slower with the wind response. This is opening the potential for
fog again. With light LL flow still in place moisture has been
increasing but at a slow rate and because of that we have mixed
in some drier air aloft. This allowed dewpoints to drop into the
50s to mid 60s again which like last night is providing favorable
conditions to allow for one more cool night. A crossover temp in
the lower to mid 60s is right around where we could see
temperatures drop to again and this would allow for some fog
production just before sunrise. The other question is just off the
deck now. Winds around h925 are still expected to increase
through the night and should approach 20 kts by 12z and could even
approach 25kt in a few areas. Winds of that magnitude would be
more than sufficient to mix the BL up and thus hurting the
potential for fog to develop leading more to a layer of stratus.
Models still are stronger with the LL winds but try to decouple
the sfc winds and seems to slow things up by about 3-6 hrs making
this a tricky forecast. Now adding the smoke that is being
produced by the multiple fires and we have a more difficult
forecast now.
With this we have issued a dense fog advisory mainly for areas
around the tidal lakes and where the smoke is likely to be
transported. That said not all areas in the advisory will see
dense fog and there is probably a good chance most of the area
doesn`t see dense fog but the problem is the potential is there.
Main concern is the immediate southshore of Lakes Pontchartrain
and Maurepas, especially Pontchartrain as once the evening
inversion develops the smoke will initially begin to be contained
near the sfc and move more west directly over the southern
3rd/half of Lake Pontchartrain and into Orleans, Jefferson, St
Charles and St John parishes. Also additional smoke from the fire
near Lafitte could make hazardous conditions more localized in
Jefferson parish. Things could begin to spread towards the
northwest into Livingston and Tangipahoa parishes a little later.
Also directly over most of the Lake fog likely will not be an
issue as winds should be stronger and thus the center and north
side of the causeway will probably be mostly fog free. That would
also translate into St Tammany and portions of Tangi until you
get farther inland closer to I-12 where the low clouds may drop to
the sfc. This is also why coastal MS is not in the adv because
much stronger winds coming off the Gulf will lead to a low cloud
issue. The probability of fog is not very high and the highest
probs are closer towards BTR but the impacts are quite high is fog
develops as the fog mixing with smoke could cause extremely
hazardous conditions again. Interesting aspect is that I-10 in
East Orleans likely wont have as great an impact as I-10 from the
CD towards Gonzales and this is likely because there will
probably be strong enough winds coming off of Lake Borgne
After fog dissipates tomorrow morning, if it develops, conditions
are rather benign with breezy and warm conditions across the
region and no fog concerns after tomorrow morning. /CAB/
&&
.LONG TERM...
(Thursday through Sunday night) Issued at 325 PM CDT Mon Oct 23
2023
Thursday through the end of the period sees conditions dominated
by upper level high pressure centered over the north central GOM
and the related surface high over the mid Atlantic coast. This
gives us little, if any, chance for rain in the forecast period.
The clockwise rotation around the high will keep winds generally
out of the southeast to east southeast. High temperatures look to
be solidly in the 80s and lows in the mid 60s to mid 70s...both
are 5- 10 degrees above normal. As far as forecast grids go, saw
no reasons to deviate from the NBM. /DSS/
&&
.AVIATION...
(00Z TAFS)
Issued at 633 PM CDT Mon Oct 23 2023
Mainly quiet/VFR this evening through around 06-08Z for all TAF
sites. Main focus for after 08Z thru 14Z will be fog production.
Anticipating slightly more SE SFC winds at around 04-07KT this
morning to around 10-15KT at 100-300ft AGL, which may help to
reduce the widespread production of dense fog. However, smoke from
nearby wildfires may still aid in FG development with an inversion
settling in near the ground, primarily from 10-13Z for TAF sites
surrounding the tidal lakes. Will be closely monitoring KNEW, KMSY
for where smoke advects, and how far downstream fog will develop
and spread to KBTR to KHDC. Confidence is low at this time, but
did keep mention of LIFR/IFR conditions for a few hours due to
this potential. Conditions do improve after the 14Z hour thru the
rest of the day with VFR prevailing. KLG
&&
.MARINE...
Issued at 325 PM CDT Mon Oct 23 2023
High pressure to the northeast will continue to slide east as
broad low pressure develops along the lee of the Rockies. This
will start to tighten the pressure gradient tonight but more so
tomorrow and into Wednesday. Winds will respond overnight and by
tomorrow moderate to strong onshore flow should be impacting all
of the area. SCS or SCY headlines will be needed tomorrow and
likely needed through Wednesday. /CAB/
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 60 87 62 83 / 0 0 0 0
BTR 65 88 67 88 / 0 0 0 10
ASD 63 85 64 83 / 0 10 0 10
MSY 69 86 70 83 / 0 0 0 10
GPT 63 82 66 80 / 0 0 0 0
PQL 60 84 62 82 / 0 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Dense Fog Advisory from 3 AM to 10 AM CDT Tuesday for LAZ048-057-
058-060-076>088.
GM...Dense Fog Advisory from 2 AM to 11 AM CDT Tuesday for GMZ530.
Small Craft Advisory from 7 AM to 7 PM CDT Tuesday for GMZ575-
577.
MS...None.
GM... Small Craft Advisory from 7 AM to 7 PM CDT Tuesday for GMZ577.
&&
$$
UPDATE...KLG
SHORT TERM...CAB
LONG TERM....DS
AVIATION...KLG
MARINE...CAB
East Central Florida Forecast Discussion
National Weather Service Melbourne FL
912 PM EDT Mon Oct 23 2023
.DISCUSSION...
Currently...Increasing winds over the marine area have brought some
isolated radar returns. A broken line of showers earlier moved
across the Treasure Coast from late afternoon past nightfall,
responsible for a few hundredths of an inch of coastal pcpn in some
spots. Based on some recent HRRR guidance and current radar and sat
depiction, gridded PoP was raised slightly along the coast overnight
to reflect a slight chc of brief sprinkles mainly south of
Melbourne.
from prev disc...
Tonight-Tuesday...The area of surface high pressure will remain in
place along the Atlantic seaboard just north of the peninsula
tonight into tomorrow. Amplification aloft of the mid-level ridge
will lead to strengthening of the high at the surface, resulting in
a tighter pressure gradient locally, leading to increasing easterly
winds. As a result, moisture will continue to be advected toward
east central Florida tonight into tomorrow, resulting in the
development of scattered cloud coverage tonight into Tuesday. Cannot
rule out a stray shower or two developing across the local Atlantic
waters. Overall though, the forecast remains dry through Tuesday.
Temperatures will remain seasonable, with afternoon highs in the low
80s and overnight lows in the mid 60s across the interior to the low
70s along the coast.
Wednesday...Stout ridging persists over the eastern US, with
surface high pressure meandering around the Mid-Atlantic, mid-
level high pressure over the northern Gulf Coast, and upper level
ridging over the GOMEX. Thus, breezy to windy onshore flow will
continue, as the pressure gradient remains tight, with ESE winds
around 15mph and gusts to around 25mph. Though rainfall is not
expected, with PoPs around 5-10%, a few isolated light showers
cannot be ruled out in the marine stratocu. Any accumulations will
be minimal.
Onshore flow will keep temperatures near-normal, with highs in the
lower 80s. However, overnight lows will be slightly above normal, in
the upper 60s inland and lower 70s along the coast.
Thu-Mon (modified previous)...The mid/upper level ridging will
weaken slightly into the extended with center of mid-level high
pressure sinking slowly into the eastern Gulf. While the pressure
gradient does gradually weaken during this time (into late work-
week), the fairly deep onshore flow will continue across the region.
Will keep conditions mostly dry thru Sat night (still cannot rule
out an isolated sprinkle/shower, especially along the Treasure
Coast), but may see a 20-30pct chance for shower activity as we head
thru the weekend and into early next week, as moisture increases
slightly. Though most locations will still remain dry and any QPF
will be light. High temps continue in the L-M80s, but could see some
U80s later in the period. Lows continue in the M-U60s to L70s
(toward coast).
&&
.MARINE...
Issued at 331 PM EDT Mon Oct 23 2023
Tonight-Tuesday...Boating conditions deteriorate through the next
couple of days. ENE winds between 15 to 20 knots will develop as a
result of a tightening pressure gradient across the Florida
peninsula and the local Atlantic waters, with gusts up to 30 knots
possible. As a result of this increasing onshore flow, seas are also
forecast to build to 4 to 8 feet tonight into Tuesday. As a result,
Small Craft Advisories have been issued for the offshore waters and
nearshore Treasure Coast waters starting at 4 AM Tue. Elsewhere,
small craft should exercise caution.
Wednesday-Friday...High pressure over the area will maintain
breezy to windy conditions over the local Atlantic waters. Current
Small Craft Advisories in effect through Thursday morning will
likely need to be expanded and extended, as hazardous boating
conditions persist into the weekend. Onshore winds 20-25kts at
times, with seas up to 8-10ft, likely through the period. Though
will start to see winds decrease on Friday as the high pressure
begins to weaken. Isolated, light showers cannot be ruled out,
especially later in the week.
&&
.AVIATION...
(00Z TAFS) Issued at 912 PM EDT Mon Oct 23 2023
VFR conditions. ENE winds will persist through the period between 10
and 15 knots coastal sites and 5 to 10 knots inland tonight,
increasing to 15 to 20+ knots Tuesday. Wind gusts up to 25 knots
will be possible during Tue afternoon. FEW to SCT clouds around 4 to
5kft will persist. Dry at the terminals.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 68 80 70 80 / 10 10 10 10
MCO 66 82 68 83 / 10 10 0 10
MLB 71 82 71 82 / 10 10 10 10
VRB 70 82 71 83 / 10 10 10 10
LEE 65 83 65 83 / 0 10 0 0
SFB 66 82 67 83 / 10 10 0 10
ORL 67 83 69 84 / 10 10 0 10
FPR 70 82 72 83 / 10 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 10 AM Tuesday to 10 AM EDT Thursday
for AMZ555.
Small Craft Advisory from 4 AM Tuesday to 10 AM EDT Thursday for
AMZ570-572-575.
&&
$$
JP/BS
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1044 PM CDT Mon Oct 23 2023
.UPDATE...
Issued at 857 PM CDT Mon Oct 23 2025
A warm front along the IA/MN border will continue progressing
northward overnight in tandem with a strengthening 45 kt LLJ over
eastern NE and western/northern IA. This forcing, combined with very
steep lapse rates in excess of 8 C/km, 1500 J/kg MUCAPE, and a plume
of seasonably top-end pwats near 1.5 inches, will create a favorable
environment for thunderstorm development overnight across
southern/east central MN and WI. Initiation is expected to take place
between 10 and 11 PM across northern IA and build northeastward with
time. Elevated multicell clusters capable of large hail will be the
main threat. SPC has introduced a slight risk along the IA/MN border.
After the activity passes off to the east/northeast with the nose of
the LLJ early Tuesday, CAMs suggest a lull in precipitation until
Tuesday afternoon. However, a persistent 25-35 kt LLJ and lapse rates
remaining in the 7.5-8.5 C/km range on the warm side of the front
could allow isolated to scattered thunderstorms to persist from
southwest to east central MN and northern WI through the morning.
Further growth of convection will then take place in the afternoon
within the same corridor and southeast as a subtle shortwave ripples
along the front. Some areas of heavy rainfall totals could
materialize given the orientation of the front and northeastward
storm motions.
&&
.DISCUSSION...(This evening through Monday)
Issued at 300 PM CDT Mon Oct 23 2023
KEY MESSAGES:
- Marginal Risk for hail potential tonight and again Tuesday
afternoon and evening across southeastern Minnesota and western
Wisconsin.
- Widespread rain likely Thursday afternoon through Thursday night, with
the heaviest rainfall again expected across southeast Minnesota
and western Wisconsin.
- Much colder by late week, with highs in the upper 30s/low 40s and
lows near or below freezing. Precipitation signal remains
uncertain, however the first snowflakes of the season may fly this
weekend.
Discussion...
Skies are mostly sunny across most of central and
southern Minnesota after a round of rain and storms early this
morning. Lingering clouds from the early round of convection remain
over western Wisconsin, thus heating will be limited. Afternoon
highs appear to be on track, in the low to mid 60s in Minnesota and
the 50s in western Wisconsin.
After a brief lull in the activity, showers and thunderstorms will
return to the forecast this evening. The Storm Prediction Center has
placed southeastern Minnesota and west central Wisconsin under a
Marginal Risk for the potential of hail producing thunderstorms
overnight. A 30 to 40 knot LLJ will advect in from the southwest
late this evening, which will will be the main forcing mechanism
behind tonight`s convective chances. RAP forecast soundings depict
an environment favorable for elevated convection, supported by 1500-
2000 j/kg of MUCAPE shown on the 12z HREF. The latest CAM suite is
in fairly good agreement when it comes to the timing of convective
initiation, with most guidance developing storms between 04-06z.
Showers and storms are forecast to move to the east northeast on the
nose of the advancing LLJ, ending in western Wisconsin around
daybreak.
The eastward shift of Tuesday`s baroclinic zone was again noted on
the latest guidance suite, so have again lowered temperatures
slightly from the Twin Cities metro area to the northwest. Highs are
forecast to range from the mid 50s in western Minnesota, to the
upper 60s/near 70 degrees in southeastern Minnesota. Broad synoptic
lift in association with convergence along the surface boundary will
aid in the development of likely PoPs Tuesday afternoon and evening.
A second Marginal Risk has been placed over virtually the same
locations in southeastern Minnesota and western Wisconsin, where a
few storms may produce large hail. The overall setup for severe hail
appears conditional, with lower instability present (500-1000 j/kg
of MUCAPE per the 12z HREF). Despite limited potential for severe
storms, general t-storm PoPs do appear likely for most locations,
with the heaviest rain forecast to fall across south central
Minnesota into western Wisconsin. The axis of heaviest rainfall, say
0.5"-0.75", will be supported by 1.4" PWATs. Communities to the far
northwest of the Twin Cities currently have slight chance PoPs, thus
significantly lower rainfall expectations. Once this round of
convection departs, drier weather can be expected for much of
Wednesday with highs in the mid 60s.
The active pattern picks right back up Thursday, as a shortwave
originating in the southern Great Plains is forecast to eject to the
northeast. Moisture transport via large scale southerly flow will
quickly work to moisten the atmosphere, with anomalous PWATs
forecast to climb well into the 90th percentile per MPX sounding
climatology. GFS, ECMWF, and GEM all illustrate a quick progression
of this wave through Minnesota and Wisconsin, which means that while
heavy rain is likely to occur, the duration of the heavier rates
will be limited. Southeastern Minnesota and western Wisconsin will
yet again be the areas of focus for the most significant rainfall
accumulation. Model soundings remain too warm for a change in p-type
during the expected period of precipitation.
The coolest air of the season to date will drop temperatures to near
Thanksgiving normals this weekend. Highs will top out in the upper
30s and low 40s, with overnight lows set to fall below the freezing
mark. PoPs are forecast to return at some point over the weekend,
though variability in timing of this potential system is adding to
forecast uncertainty at this distance. Thermal profiles will be
favorable for the first snowflakes of the season to develop should
PoPs remain in the forecast.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1044 PM CDT Mon Oct 23 2023
Showers and thunderstorms are beginning to develop across
southern MN. These storms will expand northeast through the
overnight. Cigs are expected to deteriorate toward morning area wide
to MVFR or IFR. A break in precip should occur Tuesday morning,
although some isolated-scattered activity could continue across the
same corridor as the storms overnight. Additional storms will become
widespread by afternoon along and southeast of a line from RWF to
MSP. Cigs should deteriorate further Tuesday evening.
KMSP...TS is most likely to occur between 8-11Z tonight, then 18-24Z
Tuesday, but it is still possible outside of the range Tuesday. VFR
this evening, with deteriorating conditions overnight and following
the TS.
/OUTLOOK FOR KMSP/
Wed...VFR. Chc -SHRA/IFR in the overnight. Wind N 5-10 kts.
Thu...MVFR. Chc -SHRA/IFR. Wind NE 10-15 kts.
Fri...VFR. Chc -SHRA/IFR in the morning. Wind N 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...Borghoff
DISCUSSION...Strus
AVIATION...Borghoff