Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/07/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
751 PM CST Fri Jan 6 2023
.UPDATE...
Issued at 750 PM CST Fri Jan 6 2023
Added some counties to the current Dense Fog Advisory and extended
it through mid morning Saturday based on latest area webcams,
observations, and satellite trends.
UPDATE Issued at 517 PM CST Fri Jan 6 2023
No major changes planned to the forecast this evening at the
moment. Monitoring expansion of stratus/fog field and will
determine any adjustments that may become necessary to the current
dense fog advisory.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 146 PM CST Fri Jan 6 2023
The main forecast challenge continues to be fog.
At 1 PM CST, some areas of the CWA have seen the fog and low clouds
burn off, while other areas remain socked in. And, satellite
imagery/webcams do not suggest the fog/low clouds are in any hurry
to burn off/dissipate. Temperatures are in the upper single digits
to upper teens. And, winds are light and variable.
The latest HREF along with the RAP model and the NAM model in BUFKIT
all support the potential for more fog/low stratus tonight. Several
visibility guidance products also have visibility dropping to zero
or near zero overnight. Opted for a blend of the RAP13TL and
CONSshort for the visibility grids (for aviation and for creating
fog grids for the forecast) for tonight through Saturday night.
Depending on how things go for the rest of this afternoon, there may
be some additional counties cleared from the Dense Fog Advisory.
There has been some improvement across portions of north central and
northeast South Dakota. Otherwise, if it`s still "very" foggy at 3
PM CST, the plan is to continue the Dense Fog Advisory until 9 PM
CST this evening. At that point, the next shift should have a decent
feel for if/where to re-introduce or extend in time a Dense Fog
Advisory, or cancel altogether, for the overnight hours into
Saturday morning.
Everything else in the dry short term forecast period was NBM4.0
guidance, which includes a light south or southwest wind developing
later tonight and persisting through Saturday night, and
temperatures tonight and Saturday night generally in the single
digits above zero and during the day on Saturday rebounding into
the teens and 20s.
.LONG TERM...(Sunday through Friday)
Issued at 146 PM CST Fri Jan 6 2023
The long term portion of the forecast will feature mostly dry
conditions with seasonal average temperatures.
The period begins on Sunday with an trough of low pressure crossing
the region, bringing a weak wind shift and warmer temperatures into
the area. Temperatures at 925 mb could reach above the 75th
percentile, leading to the possibility of warmer highs on Sunday.
Slightly better mixing winds, with a west to northwesterly component
would help overcome the deep snow pack across much of the CWA.
Dry conditions with seasonal temperatures will continue through the
first half of the work week, Monday through Wednesday. A deep upper
level trough should slide across the central Conus Wednesday night
through Thursday, with the main surface low passing well south and
east of the CWA. While the GFS and Canadian support dry conditions
during this time period, the ECMWF suggests light, accumulating
snowfall, mainly associated with the upper level trough. The ECMWF
also suggests a tight pressure gradient across the region, Thursday
into Friday, which may promote patchy blowing snow. Since the storm
system may occur on day 6 and 7, overall forecaster confidence is
low.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 517 PM CST Fri Jan 6 2023
Terminals KABR,KATY,KPIR,KMBG
All sites except KPIR have fallen to IFR in fog and stratus
already. The stratus is closing in on KPIR and will likely fill in
within the next few hours. The IFR conditions will linger into and
through Saturday morning.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Dense Fog Advisory until 10 AM CST /9 AM MST/ Saturday for
SDZ003>011-015>023-037.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...Dorn
LONG TERM...SD
AVIATION...Wise
Area Forecast Discussion
National Weather Service Quad Cities IA IL
535 PM CST Fri Jan 6 2023
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 215 PM CST Fri Jan 6 2023
High pressure and dry air has kept things quiet across the region.
We continue to see mostly cloudy skies, thanks to lingering cyclonic
flow over the western Great Lakes, and a mid-level shortwave that
has brought a mid-level stratus deck across the southern half of the
region. Temperatures have remained cold over northeastern Iowa, with
temperatures hovering in the upper teens, with areas over our far
south where more sunshine was seen warmed up to the middle 30s,
under generally light northwest winds.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 215 PM CST Fri Jan 6 2023
Key Messages...
1) Dry conditions expected for tonight through Saturday morning,
with some patchy fog possible
2) Chances of light accumulating snow will increase Saturday
afternoon, lasting through Sunday morning
Dry conditions will continue tonight through Saturday morning,
thanks to an area of surface high pressure and confluent flow aloft.
Latest NAM and RAP model soundings are suggesting that a rather
stout low-level thermal inversion, with lots of dry air overhead,
will develop tonight, which should result in at least some patchy
fog tonight. Some of the high-res guidance are even hinting at
perhaps some locally dense fog in some places tonight, but the NBM
v4.1 probability of visibility reductions of 3 miles or less are
around 30 to 60 percent - highest over Cedar Rapids and points
north. Still thinking some patchy fog tonight is likely, but
uncertainty remains on how widespread/dense it will become.
Eventually, fog will dissipate after sunrise Saturday. Attention
then turns to increasing chances of light snow Saturday afternoon
into the morning hours Sunday. This is developing ahead of a mid-
level shortwave trough, where 850-700 mb layer warm air and moisture
advection looks to increase.
Light accumulating snow will continue through Sunday morning,
especially across our southern areas. As the aforementioned mid-
level shortwave makes its way across central Iowa, the attendant
upper-level trough will amplify slightly, leading to a bit of a
stronger cyclonic circulation. Global models are progging a few
positive vorticity maxima that will churn around the shortwave,
with the strongest forcing expected across the southern forecast
area. However, with this forecast package, the model spectrum is
indicating a trend to lower QPF, and thus, lower snowfall amounts,
with the 25th and 75th quartiles indicating between 0.01" to
0.05" possible of total QPF. Translation: not a whole lot of
moisture to work with. Ultimately, with low snow-to-liquid ratios,
this results in only between 0.1" to 0.5" of new accumulations -
heaviest over our far southern counties.
.LONG TERM...(Sunday through Friday)
Issued at 215 PM CST Fri Jan 6 2023
Key Messages...
1) Overall, relatively dry long term period with above normal
temperatures in the 30s to mid 40s
Sunday, some lingering light snow is possible during the morning
hours across areas east of the MS River and mainly south of I-80
with a dusting of additional snow accumulations at best. Sunshine
will return area wide by afternoon as high pressure builds into
the area. Highs will be in the lower and middle 30s.
Monday through Wednesday, dry conditions will prevail as high
pressure dominates. A weak system will move across the area Monday
into Tuesday, but moisture is lacking so only expect a slight
increase in southerly flow and some warmer temperatures. Highs
Monday, Wednesday and Thursday will be in the upper 30s to mid 40s,
with Tuesday being a bit cooler behind the fropa with readings in
the mid 30s to low 40s.
Thursday into Friday, a low pressure system is forecast to move
across MO and IL bringing rain and then a switch over to snow as it
exits. There remains some timing and location differences, and
therefore confidence remains low.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 530 PM CST Fri Jan 6 2023
Starting out the TAFs with VFR conditions. However, later tonight
into Saturday morning anticipate radiational fog developing with
MVFR to IFR visibilities and areas of LIFR/VLIFR. Some stratus and
IFR/LIFR CIGs are also possible but confidence is lower on this.
A system may begin to spread some light precipitation into BRL
late in the period, but being in the last 6 hours and low confidence
I`ve left out mention.
&&
.HYDROLOGY...
Issued at 1015 AM CST Fri Jan 6 2023
The River Flood Warning for Joslin on the Rock River has been
cancelled. The river level is expected to slowly fall. The river
level may fluctuate due to ice presence.
The Flood Warning for an ice jam near River Road in East Moline,
Illinois has been cancelled. While the ice jam is expected to
continue, the impacts from the flooding are not expected to
change in the near future. Please continue to heed remaining road
closures.
&&
.CLIMATE...
Issued at 300 AM CST Fri Jan 6 2023
No changes were made to the 3 AM issuance.
Week 2: The Climate Prediction Center has above normal temperatures
favored across the Upper Mississippi Valley region for the third
week of January (13th - 19th); above normal precipitation is
slightly favored. This could mean several days with highs well above
freezing, right during the coldest time of the year.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Schultz
SHORT TERM...Schultz
LONG TERM...14
AVIATION...McClure
HYDROLOGY...14
CLIMATE...Uttech
Area Forecast Discussion
National Weather Service Lincoln IL
741 PM CST Fri Jan 6 2023
.SYNOPSIS...
Issued at 302 PM CST Fri Jan 6 2023
Quiet weather will prevail across central and southeast Illinois
tonight and Saturday, before an area of low pressure brings light
wintry precipitation Saturday night into Sunday morning. Snowfall
amounts of less than 1 inch are anticipated along and north of
I-72, with little to no snow accumulation further south toward
I-70.
&&
.UPDATE...
Issued at 741 PM CST Fri Jan 6 2023
A narrow clear slot has spread across the center of the forecast
area generally between I-74 and I-72 this evening. Model cross-
section would suggest this should persist a good portion of the
night. A ribbon of mid-level clouds from Peoria northwest also is
fairly narrow. Question will be with the area of stratocumulus
that appears to be oozing southwest out of northern Illinois.
Latest HRRR is backing off some on the speed, though it does show
it spreading south to near I-74 by 3-4 am. Did some tweaking of
the sky forecasts to back off a bit on the cloud cover across the
heart of the forecast area overnight, but increasing it again late
tonight from the north.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 302 PM CST Fri Jan 6 2023
High pressure will dominate the weather across central Illinois
over the next 24 hours...bringing partly cloudy skies and very
light winds. Several CAMs suggest patchy fog development
along/north of a Macomb to Bloomington line tonight, so have added
fog to the northern KILX CWA accordingly. After any early morning
fog dissipates, partly sunny skies will prevail until late
afternoon when clouds begin to increase/thicken from southwest to
northeast across the area. Lows tonight will mostly be in the
middle to upper 20s, with lowers 30s south of I-70. Highs on
Saturday will range from the middle 30s far north around
Galesburg...to the middle 40s south of I-70.
&&
.LONG TERM...(Saturday night through Friday)
ISSUED AT 302 PM CST Fri Jan 6 2023
Short-wave trough evident on 20z/2pm water vapor imagery over
Colorado will track slowly eastward over the next 24-36 hours,
eventually passing through central Illinois during the day
Sunday. The corresponding surface low will track well to the
south...from southeast Colorado presently to western
Kentucky/Tennessee by Sunday morning. Light wintry precipitation
associated with this system will begin to spread into parts of
central Illinois late Saturday afternoon into the evening:
however, it will be battling a dry E/NE boundary layer flow, so
think it may not precipitate along/north of I-74 until around
midnight at the earliest. The most widespread precipitation will
hold off until stronger forcing associated with the short-wave
arrives Sunday morning. Thermal profiles initially support very
light snow or a rain/snow mix during the evening before a
transition to mostly snow overnight into Sunday morning. As an
elevated warm layer aloft pivots northward, a zone of mixed precip
may develop near the I-70 corridor by morning. Any freezing rain
that occurs will be light, short-lived, and falling in borderline
temps. As a result, am expecting little to no icing. Further
north, snowfall amounts look to remain under 1 inch along/north of
I-72. Will need to keep an eye on possible banding, with isolated
amounts possibly exceeding 1 inch. The wintry precip will taper
off from west to east during the afternoon with high temps
climbing well above freezing everywhere. Think there will be slick
spots on untreated and secondary roads Sunday morning, but any
snow/ice on the roads will melt by midday as temps rise above
freezing.
Once the short-wave departs, a period of mild and dry weather will
prevail Monday through Wednesday before a more significant storm
system takes shape for the end of the week. Temps will be well
above normal for this time of year in the middle to upper 40s
throughout the extended. As a result, rain is anticipated
Thursday/Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 524 PM CST Fri Jan 6 2023
Main aviation concern will be with potential for MVFR ceilings
toward early Saturday morning. Currently seeing ceilings below
2,000 feet across northern Illinois, with some of the high-res
models suggesting a southwest push overnight. NBM and HREF show
probabilities of ceilings below 3,000 feet around 40% from KPIA-
KCMI toward 11-12Z, though the HRRR cloud height guidance is much
faster and further south. Will only include that particular
corridor for now with TEMPO potential for ceilings around 2500
feet, but will continue to monitor trends the next several hours.
Improvement is likely toward late morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...Barnes
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Memphis TN
851 PM CST Fri Jan 6 2023
...New UPDATE...
.UPDATE...
Issued at 835 PM CST Fri Jan 6 2023
A band of cooler dewpoint temperatures is currently in place
stretching from Memphis to Jackson, TN. As a result, dewpoints
were lowered in this area through 06Z. In addition, cloud cover
has increased west of the Mississippi River as a deck of mid-
level clouds moves in from the west ahead of a cold front.
Overnight, rain chances will increase with areas in northeast
Arkansas and northwest Tennessee likely to see showers by morning.
Showers will continue to move south tomorrow, with a few rumbles
of thunder possible south of the Tennessee / Mississippi
stateline. Otherwise, temperatures Saturday will vary as the cold
front pushes through. Upper 40s to low 50s are forecast for
northeast Arkansas and northwest Tennessee. Southwest Tennessee
and north Mississippi will trend warmer, with highs in the upper
50s to low 60s.
ANS
&&
.SYNOPSIS...
A few rounds of showers, and perhaps a few thunderstorms, are
expected across the Mid-South this week. One system will affect
the area beginning tonight and continuing into early Sunday as a
cold front moves through the region. The next significant
potential for rain will be late next week. Seasonal temperatures
are expected much of the next 7 days.
&&
.DISCUSSION...
(This evening through next Thursday)
Issued at 236 PM CST Fri Jan 6 2023
The CONUS remains within a split flow pattern this afternoon with
fast, quasi-zonal flow aloft over the Mid-South. A slow-moving
trough is traversing the Southern Rockies, passing beneath an
upper-level ridge nosing into the Prairie Provinces. A weaker
shortwave trough is approaching the Baja Peninsula with a strong
subtropical jet emanating across the Southwest. Large-scale
forcing for ascent will overspread the area tonight, aiding in the
development of light rain showers after midnight. Mesoscale
forcing will be enhanced via low-level frontogenesis beneath a
convectively unstable layer around 700 mb. This precipitation will
move gradually south late tonight into Saturday morning. A few
rumbles of thunder are possible on Saturday, mainly from Memphis
south, though the severe weather threat remains very low.
A surface low will move across the Mid-South Saturday night as the
upper-level trough over the Rockies sweeps across the Midwestern
states. Showers and thunderstorms will be most likely along and
south of a cold front attendant to the surface low, primarily
over north MS and portions of West TN. Total QPF is expected to
remain less than 1" in most areas, though localized higher amounts
will be possible within any convective elements that develop.
Most of this activity will clear the CWA by Sunday morning,
leaving generally benign weather heading into early next week as
shortwave ridging develops over the region.
Another shortwave trough will move across the area Monday night
into Tuesday, pushing another weak cold front through the Mid-
South. Ensemble guidance isn`t exactly bullish on rain chances
with this system but both the deterministic GFS and ECMWF offer
light QPF Tuesday morning. This was worth a slight chance for
showers across north MS and portions of West TN. Regardless, QPF
looks to be fairly light given the general dearth of moisture
(precipitable water ~0.50"). Once this system passes, we`re
looking at 36 hours or so of pleasant weather with system
temperatures. However, a late week trough will bring rain chances
back into the forecast by Thursday, continuing into Friday. This
system currently appears to lack in instability, keeping the
potential for significant convection low.
&&
.AVIATION...
(00Z TAFS)
Issued at 553 PM CST Fri Jan 6 2023
VFR to prevail for the better part of tonight, as mid and upper
level moisture spreads through the region, in advance of an upper
level disturbance lifting through the Ozarks. Marginal LLWS will
precede this disturbance, affecting all but TUP overnight.
MVFR potential will increase at all but TUP following sunrise
Saturday, as showers become more widespread.
TSRA potential should hold off until late Saturday afternoon. 18Z
HRRR model depicts TSRA in the southern MEM TRACON by 00Z/08, with
the terminal dropping to IFR on the cool side of a surface front.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...MJ
AVIATION...PWB
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
611 PM CST Fri Jan 6 2023
.DISCUSSION...(This evening through Friday)
Issued at 234 PM CST Fri Jan 6 2023
KEY MESSAGES: (Same as previous discussion)
- Light winds and a stagnant airmass will allow for the potential
development of fog and low stratus each day into early next week.
- Next chance of snow arrives mid to late next week, though nothing
major at this time.
TODAY AND THROUGH SATURDAY NIGHT - Early afternoon satellite imagery
with metars and RAP surface analysis showed partly cloudy skies
across the Upper Midwest, with a few areas of fog and light snow
showers beneath a very thin stratus deck in some locations. Surface
high pressure was in place, meaning very light winds and seasonably
cool temperatures.
The main story over the next 36 hours is the high likelihood of fog
develop again later this evening into Saturday morning given the
synoptic setup outlined above. HiRes models are in good agreement
that visibility will drop down to near 1/4 mile in a few locations,
so have continued with expansive fog wording in the weather grids,
and should have low stratus expand as well. There is a chance a
dense fog advisory may be needed, but since this is radiation fog
will hold off and wait for more guidance in order to see the trends.
This fog will be slow to clear out on Saturday as high pressure
remains in place but southerly winds will start to develop later in
the day which should promote some mixing. There is a chance for some
fog to redevelop again Saturday night, with the greatest chance east
of I-35.
SUNDAY THROUGH FRIDAY - A prolonged stretch of dry weather with
warmer temperatures continues Sunday into early next week. Winds
still remain light, so as mentioned in the previous discussion,
could see a repeat of fog/stratus into early next week. Temperatures
moderate a bit, with highs on Monday in the 20s west, and near 30
east. Looking ahead, a split upper level trough will approach the
region Wednesday, and this will bring a chance for some rain/snow
chances later in the week. Chances are small (10 to 30 percent) with
the highest percentage in eastern Minnesota and western Wisconsin.
Temperatures will remain in the mid 20s to lower 30s, with lows
generally in the teens.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 547 PM CST Fri Jan 6 2023
We will have a moist and stagnant airmass again tonight, with
freezing fog again likely. How widespread it will be, when it will
set in, how long it will last are all a bit unknown. At this point,
we already have a good collecting of MVFR or low VFR vsbys out there,
so decided to lean toward the short term guidance, which are all
really aggressive with fog development tonight. Like this morning,
any fog we do see will be slow to improve given the light winds and
low sun angle leading to an environment with weak mixing. Saturday
night looks to be more of the same with the exception of western MN,
where a weak return flow will be setting up.
KMSP...Decided to lean toward the HRRR/LAV in bringing fog into MSP,
this is not a high confidence forecast, but we`re certainly primed to
see dense fog really slow things down the start to Saturday and
Sunday as well...
/OUTLOOK FOR KMSP/
SUN...VFR. Chc MVFR/IFR w/AM FZFG. Wind S 5-10kts.
MON...VFR. Wind SW 5-10kts.
TUE...VFR. Wind NE 5-10kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...JRB/BPH
AVIATION...MPG