Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/23/24
Area Forecast Discussion
National Weather Service La Crosse WI
535 PM CST Mon Jan 22 2024
.KEY MESSAGES...
- Wintry mix still looking likely for parts of northeast IA and southwest
WI overnight through Tue morning. A glaze of ice and under an
inch of snow possible. With the freezing pcpn threat, a
Winter Weather Adv has been issued for a small portion of NE
IA/SW WI.
- Precipitation chances return for Wed/Thu...trending toward
mostly rain.
- Mild, above normal temps through the week.
&&
.DISCUSSION...
Issued at 155 PM CST Mon Jan 22 2024
- OVERVIEW: long range guidance continues to show the swing to more
zonal/broad ridging in the upper level flow for the new week. Bits
of energy in the southern and northern parts of the flow could bring
pcpn chances (from time to time) to the region, highlighted more
from southern origin shortwaves. The ridging will promote warming
with above normal temps still on tap through the week - potentially
continuing into next week.
- WINTRY MIX CHANCES TONIGHT-TUE: bits of upper level shortwave
energy currently spinning over TX/southern plains still on track to
lift northeast tonight, moving across the mid mississippi river
valley toward the eastern great lakes. Bulk of the low level
thermodynamics progged to hold south/east of the local forecast
area, but latest RAP suggests narrow 600:700 mb Fgen band from NE IA
into southern WI tonight into Tue morning.
While not "much" in the way of cyclogenesis/storm development,
enough forcing mechanisms and available moisture for pcpn chances -
especially across the south. What falls and how much remains the
bigger questions.
Temperature profile in the vertical along with depth of
saturation/ice in cloud continue to present challenges with still
some disagreements between the variety of short term guidance in
how those will "look".
Trends that the guidance do agree on is a deepening of the
saturation from south to north tonight/Tue morning, deepest south of
I-90. Warm layer at 800:850mb could provide partial/full melting to
any frozen pcpn with a warmer, more uniform layer to the sfc
developing through the day Tue.
Resulting breakout out of QPF is under 1" of snow and potential for
a glaze of ice over parts of northeast IA and southwest WI. Will
issue a Winter Weather Adv for parts of these areas to cover mainly
the icing potential.
- WED/THU PCPN CHANCES: next shortwave trough follows quickly behind
Tue`s, taking a similar track, and perhaps a tad perkier with better
upper level jet dynamics and more shortwave energy. The better low
level thermodynamics hold southeast of the local area but there
remains a fetch of southerly moisture to provide some fuel for pcpn
chances. Pretty much all the GEFS and EPS members paint at least
light QPF from Wed into Thu, although the GEFS is more northeast
with the layout and perhaps a bit faster.
For pcpn type, mild air continues to spread northward evidenced in
north-south running x-sections and bufkit soundings. The amount of
near sfc warming would suggest rain-snow chances, leaning more into
rain. Can`t completely rule out a brief period of freezing rain Wed
morning when possible loss of ice in clouds and sfc temps could
support it. QPF currently sits around 1/4", with only a 5 to 10 % to
exceed 1/2". Little if any snow accums currently suggested, with
ratios likely closer to 6:1.
A bit of northern stream energy could quickly drop in behind the
departing shortwave for Thu night, bringing another quick shot for
pcpn. GFS currently favors some light qpf while the EC is trending
dry with this feature.
- MILDER TEMPS RETURN: Temperatures still on the upswing with height
increases/influx of milder southerly air. GEFS and EPS members are
steadfast with promoting above normal temps with mid/upper 30s highs
for most (could push 40 at some locations) while lows only bottom
out a few degrees below freezing. With differences of only a few
degrees between the 10-90% for temps, confidence remains high the
progged outcomes will be realized.
Looking ahead, SPC clusters promote anomalously strong ridge
building to the west that could start shifting east across the
northern plains/upper mississippi river valley for the start of next
week. While the spread in GEFS and EPS members increases, the trends
favor an increase in warmth - with upwards of 25-50% of the members
suggests 50+ highs could be reached. Might be wishful thinking, but
going to lose a bunch of snow cover this week and NAEFS/EPS 850mb
temp anomalies already around +1.5 that far out. Something to keep
an eye on, but don`t get too excited (if you like mild air) quite
yet.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 535 PM CST Mon Jan 22 2024
Expect deteriorating flying conditions overnight into Tuesday
as low-level moisture lifts northward across the region.
Although timing may need to be refined, followed the previous
TAF issuance trending ceilings into the LIFR/IFR range
overnight. With light flow, fog may develop with at least low to
medium chances (30-60%) for LIFR visibility, especially at
KRST, and fog could become locally dense. The higher chances for
precipitation will remain across northeast Iowa and southwest
Wisconsin, although small (10-20%) drizzle/light snow chances
could not be ruled out for a time on Tuesday for areas to the
north towards I-90. Confidence is not high enough to include in
the TAFs at this time.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 2 AM to noon CST Tuesday for
WIZ061.
MN...None.
IA...Winter Weather Advisory from 2 AM to noon CST Tuesday for
IAZ029-030.
&&
$$
DISCUSSION...Rieck
AVIATION...JM
Area Forecast Discussion
National Weather Service Denver/Boulder CO
808 PM MST Mon Jan 22 2024
.KEY MESSAGES...
- Low confidence in the development of dense fog late tonight
through Tuesday morning across far northeast Colorado.
- Seasonal temperatures with periods of light mountain snow
showers through Friday.
&&
.UPDATE...
Issued at 806 PM MST Mon Jan 22 2024
Convective driven snow showers have pretty much ended in the mtns
early this evening with some virga over the plains. Overall,
expect limited activity the rest of the night over the higher
terrain.
Meanwhile, as far as fog over the far northeast plains, the last few
runs of the HRRR have backed off on the development of dense fog
late tonight thru Tue morning. Thus, overall confidence with the
development of dense fog is currently low, so will just leave areas
of fog for late tonight thru Tue morning.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 243 PM MST Mon Jan 22 2024
Today`s weather certainly has a March-like feel to it. You could
go outside for a walk and get by with not bringing a coat. Plus,
there are convective snow showers in the mountains. Not too bad
for late January.
Radar shows snow showers have blossomed over the Front Range
mountains this afternoon with a few spots of 40 dbz. This has
been aided by weak instability as the SPC mesoanalysis shows 100
j/kg of CAPE across higher elevations in our forecast area. Under
the more intense snow showers, there will briefly be moderate
snowfall rates (0.5-1" per hour) but any snow showers will be
short-lived. Model guidance suggests the I-70 mountain corridor,
South Park, and the southern foothills will see the brunt of the
snow showers this evening. PoPs and QPF were raised such that the
expected snowfall for much of that area is between a trace to 2
inches. There won`t be any highlights issued for this snowfall but
there is some concern that I-70 and other mountain highways may
become slick and/or snow-covered this evening which would lead to
poor travel conditions.
Across the plains, there are very light radar reflectivities showing
up with no precipitation hitting the ground. Through the rest of the
afternoon and evening, there will continue to be virga showers
although some legitimate rain showers may form over the Palmer
Divide. Some runs of the HRRR having been showing up to 0.20" of
QPF falling over Douglas County. Amounts that high seem
unrealistic but that area will need to be watched this evening for
a mix of rain and snow showers.
The only other impactful aspect of the forecast will be fog across
the far northeast corner. Weak upslope flow across northeast
Colorado will pull in lower clouds and moisture from Kansas and
Nebraska overnight. Model guidance suggests that fog over
Phillips and Sedgwick Counties along with portions of Logan County
is likely this evening so the extent of the fog in the forecast
was extended. There was consideration for issuing a Dense Fog
Advisory but until there is a better indication of the visibility
associated with this fog, no highlights will be issued.
On Tuesday, there will be weak flow aloft without much in the way of
QG ascent or descent. It will be another mild day across the plains
with a mix of clouds and sun. There will again be weak instability
over the higher mountains which could create some light snow showers
but coverage and intensity will be much less than Monday. With light
winds, there will be no hazardous weather on Tuesday.
.LONG TERM...(Tuesday night through Monday)
Issued at 243 PM MST Mon Jan 22 2024
Tuesday night into Wednesday, weak and poorly organized trough over
the Great Basin, will make its way across New Mexico and into the
TX/OK panhandles by 00z Thursday. The flow aloft will be quite weak
as will the QG ascent, much of which will remain to the south of the
forecast area. Light snow showers will be possible in the mountains
with minimal accumulations possible over the higher elevations.
Across the plains, it will be dry. Southeasterly winds will advect
some low level moisture (stratus/fog) into the northeast plains, so
patchy/areas of fog will be possible late Tuesday night into
Wednesday morning. Most of this should remain to the north and east
of Denver. It`s not in the grids now, but some of the models suggest
a brief window for patchy fog in Denver from 12-15z Wednesday
morning. Otherwise, temperatures on Wednesday will be near normal.
There will a chance of snow showers in the mountains Wednesday
evening mainly along the higher north/west facing slopes. Thursday
into Friday, there will be another increase in light snow showers
over the mountains as another weak disturbance over UT Thursday
afternoon, drops into the OK/TX panhandles on Friday. This system
is closer than the first system, but it is still relatively weak
with the best lift passing to the west and south of the forecast
area. The greatest snow coverage will be Thursday night as this
system transitions to the southeast. There will be a little bit of
NNE low level upslope with this system by Friday morning, so cooler
temperatures across the plains with a chance of snow will exist
along the south of the Palmer Ridge. Over the weekend, a ridge of
high pressure will build over the Central Rockies, with the
mid/level northwesterly flow increasing over CO on Saturday. Sunday
into Monday the ridge builds into the region resulting the dry and
warmer weather along with weaker winds in the mid/upper levels.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 439 PM MST Mon Jan 22 2024
Expect mainly VFR conditions thru the period. Ceilings may be
around 8000 ft at times between 00Z and 04z, otherwise they should
be 10000 ft or above tonight. There is some potential for low
clouds/fog between 12z and 15z on Tue, however, confidence is low
that it will happen at this time.
WInds will start out easterly but will shift to more southeast by
02z. Winds will become more south by 05z. By 12z Tue winds will
become light and variable in direction and then shift to a southeast
component by 19z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RPK
SHORT TERM...Danielson
LONG TERM...Cooper
AVIATION...RPK
Area Forecast Discussion
National Weather Service Burlington VT
1003 PM EST Mon Jan 22 2024
.SYNOPSIS...
A weak front dropping southward from Quebec will produce some light
snow across central and northern portions of the region tonight with
accumulations generally an inch or less. Quiet weather follows for
Tuesday before a stalled front across southern New England will move
north as a warm front late Tuesday through Thursday. Widespread
light snow is expected Tuesday night into Wednesday, and will turn
to a wintry mix of freezing rain and rain by Thursday. Temperatures
from Thursday to Saturday will be about 5 to 10 degrees above normal.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 956 PM EST Monday...The boundary has been bringing
scattered to numerous snow showers over the last 3 hours, but
it`s beginning to become much more diffuse. Radar returns are
splitting over northern New York with another round moving into
western St Lawrence County. Lighter showers should continue in
the Adirondacks with the upslope flow ongoing. Showers over the
Champlain Valley have yet to reach the ground given the very
dry surface layer, but a dusting is still possible as cloud
layers lower with flurries evident on webcameras.
Previous Discussion...The forecast is well on track with snow
falling in the St Lawrence Valley just ahead of a weakening
frontal system. The biggest question will be how much, if any
snow falls in the northern Champlain Valley. Wind speeds aloft
suggest downsloping will win out keeping chances low. However, a
dusting cannot be completely ruled out if forcing along the
boundary can remain until the boundary begins washing out as it
drops south. Biggest hazard will be periods of poor visibility
with wind-whipped snowfall over northern New York especially
along Highway 11.
Previous Discussion...Overall the main idea from the previous
forecast still holds true for the next 36 hours. A weak front on
the leading edge of an arctic high will drop across the
Canadian border tonight before fizzling out, but not before
producing some light snow showers across central/northern
portions of the region. Surface convergence will be focused
across the St. Lawrence Valley, northern Adirondacks and the
northern Greens as southwest flow persists in the low levels,
but given such dry antecedent conditions, snow accumulations of
only a dusting to 2" are expected through mid- morning Tuesday.
Dry conditions follow thereafter for the bulk of Tuesday, before
a stalled boundary draped across the PA/NY/MA border begins to
shift north as a warm front late Tuesday into Tuesday night.
Overrunning precipitation should win out over dry surface
conditions by the evening hours with light snow developing from
south to north through the night. QPF looks quite meager with no
real low-level frontogenesis to speak of, so just looking at
another round of light accumulations of 1-3" central/south and
D-2" central/north. Abundant cloud cover through the period will
keep temps relatively close to normal during the daylight hours
with Tuesday highs in the upper 20s to low 30s, but overnight
temps will be very mild with lows both nights in the teens to
20s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 343 PM EST Monday...A very challenging temp fcst and associated
light precip fcst during this period as cold arctic high pres is
lingering acrs northern Maine. Have integrated the high res NAM 3KM
and HRRR 2m temps into our fcst for Weds into Weds night. Soundings
show a very sharp and shallow llvl inversion, especially near KMSS
associated with northeast drainage down the SLV, northern Dacks
north of Route 11, and wl have to watch northerly CPV/NEK closely.
For highs on Weds have readings struggling to reach 20F northern
SLV, while Potsdam to Malone warm into the mid 30s, similar to
central/southern CPV, while east of the Greens stay mostly in the
20s. Have continued with high likely/low cat pops for Weds morning
associated with waa lift/moisture. Guidance is not overly impressive
with forcing and moisture is weakening as it encounters cold/dry
1040mb arctic high pres to our north. So mainly a dusting to 2
inches of snow, and used the word light to describe precip, given
the anticipated qpf. For Weds aftn/night, ECMWF and GFS show
secondary surge of waa lift/moisture moving from sw to ne acrs our
cwa. Thermal profiles, especially near sfc remain very complex given
position of sfc high pres. So thinking a period of freezing
rain/wintry mix is likely, especially SLV/northern NY and most of
central/eastern VT, including the NEK. A winter wx advisory wl
eventually be needed for this time frame for light icing potential,
especially given very cold ground temps. Cold air always remains
trapped longer than anticipated acrs the northern SLV and valleys of
central/eastern VT, so have tried to show that trend in the grid sfc
temps. Crnt fcst has btwn a few hundredths to two tenths of an inch
of ice, with highest ice accumulations northern SLV and east of the
Greens. Temps ranging from the l/m 20s to l/m 30s overnight on Weds,
with warmest in the CPV and western Dacks.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 343 PM EST Monday...A complex and challenging long term with
periods of occasional light precip anticipated every 6 to 12 hours,
but timing predictability of individual s/w`s decreases as we head
into the weekend, as spread in guidance increases. Large scale
pattern features a mid/upper lvl ridge off the southeast coast,
while arctic high pres is lingering over central/southern Canada,
creating a sharp thermal contrast acrs the region, especially toward
the weekend.
Have noted a large spread in temps of 12 to 15 degrees on Sunday
into Monday, as some guidance hints at low level arctic air bleeding
into our region. For now have kept very close to NBM and wl trend
toward warmer/cooler solutions as time frame becomes closer. As far
as precip, next wave in the fast confluent flow aloft arrives late
Thurs into Friday with another round of light precip likely. Thermal
profiles indicate mostly rain, but 1028mb sfc high pres is still
lingering acrs northern Maine, so the potential for light freezing
rain is possible, especially northern SLV and east of the Green
valleys where cold air remains trapped. Expect high res data wl have
a better idea of llvl thermal profiles and wl integrate as time
frame is better sampled by high res models. For now have temps
trending much above normal for Thurs into Friday with highs mid 30s
to mid 40s depending upon location/elevation, supported by progged
925mb temps 3-5C. QPF and warmup is not expected to cause any hydro
related issues thru Friday and into the upcoming weekend.
Cooler air finally filters back into the region on Sat into Sun,
with increasing spread in the guidance late weekend into early next
week. GFS shows arctic high pres and much cooler/drier air, while
ECMWF hints at additional precip with much stronger low pres
tracking from Ohio Valley into Mid Atlantic, with widespread wintry
precip acrs our cwa. Given the split flow scenario in the mid/upper
lvls and time frame, the overall predictability in temps/wx is very
low attm.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...Snow has started at MSS/OGS and is
progressing eastward as a front tracks through the region. IFR
conditions are evident with VIS down to 1SM at MSS and will
continue through 04Z when the boundary tracks southeastward.
SLK/EFK have appreciable chances of IFR through 06Z as well. For
PBG/BTV, showers will be largely shadowed out by southwesterly
flow aloft, but a dusting and periods of MVFR will be possible
through 06Z in snow showers. After 06Z, MVFR CIGs settle over
the North Country with flow turning west/northwesterly. Showers
may not continue at BTV, but upslope component of wind will keep
showers in the vicinity through 12Z. For RUT/MPV, shower
chances are lower, but additional CIGs begin to lower towards
the end of the forecast period with another system approaching
the region with widespread snow likely with periods of
IFR/MVFR.
Outlook...
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SN.
Wednesday: Mainly MVFR and IFR, with local VFR possible. Likely
SN, Slight chance FZRA.
Wednesday Night: Mainly MVFR, with areas IFR possible. Chance RA,
Chance FZRA.
Thursday: Mainly IFR, with local MVFR possible. Likely RA, Chance
FZRA.
Thursday Night: Mainly IFR, with local MVFR possible. Likely
SHRA.
Friday: Mainly IFR, with local MVFR possible. Chance SHRA.
Friday Night: Mainly IFR, with areas MVFR possible. Slight chance
SHRA, Slight chance SHSN.
Saturday: Mainly MVFR, with local IFR possible. Slight chance
SHRA, Slight chance SHSN.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Lahiff
NEAR TERM...Boyd/Lahiff
SHORT TERM...Taber
LONG TERM...Taber
AVIATION...Lahiff
Area Forecast Discussion
National Weather Service Corpus Christi TX
930 PM CST Mon Jan 22 2024
...New UPDATE...
.UPDATE...
Issued at 921 PM CST Mon Jan 22 2024
Moisture/dewpoints are running ahead of what we had in the grids,
so have updated them, however, so far the lowest inland visibility
is 3 miles, so have held off issuing a dense fog advisory. However
KRKP is down to 1/4 mile and several site along the Corpus Christ
Ship Channel are below 1 mile, so have issued a Marine dense fog
advisory as the dense fog comes and goes tonight. Water
temperatures are running the lower to mid 50s, while the dewpoints
are in the lower 60s at the Coast and around 60 much further
inland. Otherwise, the temperatures and the winds look to be in
line with the going forecast.
&&
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 319 PM CST Mon Jan 22 2024
Key Messages:
▶ Marginal to Slight Risk of Flash Flooding through Tuesday Night
▶ Marginal Risk of Severe Weather Tuesday Evening through
Wednesday Morning
▶ Minor coastal flooding through this evening
▶ High risk of rip currents through Tuesday
Showers and rain chances have shifted eastward over the waters and
HGX along with the mid-level shortwave disturbance and upper trough.
There will remain a lull in rain chances through early this evening
until another mid-level disturbance pushes through enhancing
positive vorticity late in the evening into the overnight period.
Due to this mid-level support combined with 99th percentile PWAT
values near 1.50" have a moderate chance (30-50%) of showers and
thunderstorms. In addition, in areas that are absent from rain
activity, light winds with increasing dewpoints and saturated soils
may become favorable for patchy to areas of fog development.
Greatest chances for areas of fog will be over the inland Coastal
Plains and northern Brush Country.
Rain chances will diminish west to east Tuesday morning as
favorable conditions focus north of the CWA and extend into the
Victoria Crossroads Tuesday afternoon.
Our greatest concern is late Tuesday evening into the overnight
hours with SPC issuing a marginal risk of strong to severe storms
and a marginal to slight risk of flash flooding. Another ejecting
shortwave with notable positive vorticity from 850-700mb
collocated with the right entrance divergent region of the jet
stream and near record PWAT values will aid in redevelopment of
convection. Rain chances become high overnight (60-80%) with
isolated elevated supercell development possible as mentioned by
SPC. Just looking at HRRR soundings around 09Z Wednesday, MUCAPE
near 1500 J/kg, effective shear over 50 knots, and a long
hodographs support severe hail and isolated tornadoes. We`ll
continue to closely monitor. Although it`s winter, be sure to have
multiple ways to receive warnings.
Lastly, long period swells and swell wave heights have led to
minor coastal flooding along area beaches and have resulted in a
Coastal Flood Advisory through 8 PM this evening. In addition,
there is a HIGH risk of rip currents through Tuesday.
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 319 PM CST Mon Jan 22 2024
Key Messages:
- Periods of heavy rainfall through mid week could lead to isolated
flash flooding.
- Isolated strong to severe thunderstorms possible through Wednesday
night across the Victoria Crossroads.
A couple of mid to upper level troughs are progged to move across
the Southern Plains mid to late week, which will combine with the
available moisture to continue to generate showers and thunderstorms
over the area. Rain chances will be highest Wednesday into Wednesday
night with PoPs around 50-90% over locations east of I-37 during the
daytime hours, and near 40-60% overnight. Energy ahead of the first
passing upper level disturbance will maintain a Marginal risk for
severe thunderstorms across portions of the Victoria Crossroads
Wednesday into Wednesday night as the associated boundary slides
through. In addition, a Marginal to Slight ERO remains in place for
the eastern half of the CWA during that same time frame. Localized
flooding will continue to be possible as soils become saturated from
the rain earlier in the week.
The secondary trough and associated frontal boundary will push
across the area by the end of the week, with the front arriving
Friday night into early Saturday. Although enough moisture will
linger around to provide a slight chance (15-25%) for showers
through Saturday, most locations will remain dry. Drier and cooler
conditions will then follow into the weekend as ridging builds
over the area.
Highs will fall from the mid 60s to mid 70s range mid week into the
50s and 60s over the weekend behind the secondary boundary.
Overnight lows are forecast to drop into the 30s again Sunday night
into Monday morning.
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM CST Mon Jan 22 2024
VCTS returning overnight. IFR/LIFR ceilings return overnight into
tomorrow morning as moisture saturates in the lower levels due to
the nocturnal inversion. VSBYs will be restricted to MVFR/IFR
likely. Rain and thunder chances continue Tuesday, with the focus
over the Victoria Crossroads going into the evening. Tried to
limit the thunder to the most likely time frame Tuesday, but it
thunder is possible going past 00z/Wed. Fog will also be an issue
as we continue an inversion that keeps moisture trapped into
Tuesday night as well.
&&
.MARINE...
Issued at 319 PM CST Mon Jan 22 2024
Moderate onshore flow will continue through Tuesday, then become
weak Tuesday night. The Small Craft Advisory has been extended
through Tuesday morning over the offshore waters for wave heights
over 6 feet. Scattered showers and thunderstorms are expected
tonight through Tuesday night with a lull in activity during the
day on Tuesday. Sea fog will also be a concern during the early
mornings with warmer dewpoints overrunning cooler water
temperatures. Numerous to widespread showers and thunderstorms
are expected through the middle of the week, becoming isolated to
scattered late this week. Weak to moderate winds will shift to the
east and northeast Thursday, and remain out of the east through
Friday. A cold front will move through the area Friday night with
the flow becoming northerly behind it.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 61 74 64 74 / 40 20 70 60
Victoria 58 72 61 71 / 50 50 80 90
Laredo 59 75 61 74 / 40 20 60 20
Alice 60 76 63 75 / 40 30 70 40
Rockport 58 68 61 67 / 40 30 70 70
Cotulla 57 72 59 70 / 50 40 60 30
Kingsville 61 76 65 75 / 40 30 70 40
Navy Corpus 60 69 63 70 / 40 20 70 70
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Tuesday afternoon for TXZ345-442-
443-447.
GM...Dense Fog Advisory until 7 AM CST Tuesday for GMZ231-232-236-237-
250-255.
Small Craft Advisory until noon CST Tuesday for GMZ270-275.
&&
$$
SHORT TERM...EMF
LONG TERM....ANM
AVIATION...JSL
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
432 PM MST Mon Jan 22 2024
...New AVIATION...
.SYNOPSIS...
Issued at 222 PM MST Mon Jan 22 2024
Moisture continues to stream in off the Pacific Ocean and across
the Borderland over the next several days. Showers and mountain
snow will develop again late this evening and continue into
Wednesday before tapering off. Heavy Some flurries are possible
over the mountains into Thursday and Friday with other impulses.
An upper ridge will move in over the Desert Southwest for the
weekend, with mostly clear skies and above normal temperatures.
&&
.DISCUSSION...
Issued at 222 PM MST Mon Jan 22 2024
Next series of Pacific impulses are on schedule to arrive tonight
and last into at least Wednesday. WV imagery shows exiting trough
now over east Texas with main circulation back over the Texas
Panhandle. Any wrap around moisture from this feature has also
cleared our area to the northeast. Next system is now moving into
SoCal and the Baja, with higher clouds already moving over our
area. HRRR looks good with the timing, beginning showers out west
around 04Z and then spreading east and north, with all the area
seeing a chance by 12Z. Models showing another decent shot of snow
for the mountain zones. Went with snow advisory for the higher
mountain zones beginning late this evening into Wednesday morning.
Models begin time for this event is pretty similar but the ending
differs some. GFS/NAM12 hold on to some pcpn through Wednesday
night, while the ECMWF is done by Wednesday afternoon. All 3 of
these models do show weak disturbances floating by north of the
CWA, so the mountain zones could see a few flurries on Thursday
and Friday. Snow levels will remain around 6500 to 7000 feet
through this entire period.
Otherwise the weekend looks pleasant as upper ridging builds in.
Seasonable temperatures through Friday should warm back up above
normal for Saturday through Monday. GFS shows some promise mid
part of next week for some rain but ECMWF not buying it at this
time.
&&
.AVIATION...
(00Z TAFS)
Issued at 428 PM MST Mon Jan 22 2024
Clouds continue to increase with showers approaching the area
ahead of a wet upper-level system. Ceilings will likely lower to
the 030-050 range as rain starts sometime after 05z for DMN, 06z
for LRU and ELP, and 10z for TCS. Rain looks to be near continual
through morning with SCT SHRA possible through the afternoon. A
few rumbles of thunder are also possible. Periods of MVFR are
possible within heavier showers, both from VIS and CIG reductions.
IFR cannot be ruled out either, but generally not expected. Winds
will gradually shift from the west to south throughout the period
with speeds around 10 knots and a few gusts to 20 knots.
&&
.FIRE WEATHER...
Issued at 222 PM MST Mon Jan 22 2024
No fire weather issues on the horizon as we head into a two day
west period (Tuesday and Wednesday) and only slow drying out by
Friday and Saturday. Temperatures seasonable through Friday then
warming up above normal for the weekend. No significant winds
expected during this period.
Min RHs: Lowlands 40-50% through Thursday, then 20-30% into the
weekend. Mountains 55-75% through Thursday, then 30-45% into the
weekend. Vent rates poor-fair Tuesday and Wednesday, then mostly
good Thursday and Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 45 59 42 59 / 80 100 50 40
Sierra Blanca 42 57 37 55 / 80 100 50 20
Las Cruces 41 56 38 57 / 80 100 50 30
Alamogordo 37 54 35 53 / 40 100 40 30
Cloudcroft 25 35 23 36 / 40 90 60 40
Truth or Consequences 38 52 36 55 / 50 100 30 20
Silver City 37 46 36 47 / 90 100 60 40
Deming 40 56 37 57 / 90 100 50 40
Lordsburg 40 54 38 53 / 100 100 70 60
West El Paso Metro 45 58 40 57 / 80 100 50 40
Dell City 38 58 34 57 / 50 80 30 20
Fort Hancock 42 61 37 59 / 80 100 50 30
Loma Linda 40 52 37 52 / 70 100 40 30
Fabens 44 60 39 58 / 80 100 40 30
Santa Teresa 42 57 37 56 / 80 100 50 40
White Sands HQ 45 57 43 58 / 70 100 60 40
Jornada Range 39 54 37 56 / 70 100 50 40
Hatch 39 57 36 59 / 70 100 40 30
Columbus 44 58 40 57 / 90 100 50 50
Orogrande 40 54 38 55 / 60 100 50 30
Mayhill 30 49 28 49 / 40 80 40 40
Mescalero 29 44 28 45 / 40 100 60 30
Timberon 27 43 26 44 / 50 100 50 30
Winston 30 47 29 50 / 50 100 30 20
Hillsboro 35 52 32 55 / 70 100 40 30
Spaceport 37 53 35 55 / 50 100 30 20
Lake Roberts 32 45 31 47 / 90 100 50 60
Hurley 35 50 35 51 / 90 100 50 40
Cliff 38 52 37 53 / 90 100 50 50
Mule Creek 37 48 37 49 / 90 100 50 50
Faywood 37 49 35 52 / 80 100 40 40
Animas 41 55 37 55 / 100 100 70 60
Hachita 41 56 38 54 / 100 100 50 50
Antelope Wells 42 56 38 55 / 100 100 60 60
Cloverdale 40 48 38 49 / 100 100 70 60
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...Winter Weather Advisory from 11 PM this evening to 5 AM MST
Wednesday for NMZ426.
Winter Weather Advisory from 3 AM Tuesday to 8 AM MST Wednesday
for NMZ414-415.
&&
$$
FORECASTER...34-Brown
Area Forecast Discussion
National Weather Service Houston/Galveston TX
539 PM CST Mon Jan 22 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday Night)
Issued at 343 PM CST Mon Jan 22 2024
We did manage to get some thunder with this last batch of activity
that is currently tracking east out of the CWA. There`s still some
lingering development in the wake of that main line, but the over-
all trends are indicating that we`ll get a break this evening from
the rain. However, with the persistent WAA in place, patchy fog as
well as spots of drizzle will be possible tonight over the region.
At the coast, sea fog could make a return. Overnight lows will run
warmer given the onshore flow, with temperatures ranging in the low
to mid 50s across the northern counties and upper 50s to around 60
for the central/southern counties.
As we head into early Tues morning, models are pointing to another
round of rain/storms forming over Central/South Central TX that is
then expected to track east into our CWA. This appears to be cour-
tesy of yet another upper jet streak (with SE TX in the RRQ) along
with the development of another LLJ intensifying across the Brazos
Valley/Piney Woods portions of the CWA. Additional shortwaves will
also be possible. As such...SE TX is in a Marginal Risk for Severe
Weather (level 1 of 5) for both Tues and Weds. However, the better
chances will likely be across the aforementioned northern counties,
closer to the stronger dynamics.
Additionally...SE TX is also going to remain in a Slight Risk for
Excessive Rainfall (level 2 of 5) tonight through (at least) Weds.
Progged PWs for these next couple of days will range from 1.3-1.8
inches. Rainfall amounts should average from 0.25-0.50 inch over-
night...but totals could be higher tomorrow: 1 inch or less south
of I-10 and 2-3 inches north. 41
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 343 PM CST Mon Jan 22 2024
Guidance maintains a messy swly flow aloft into Friday. Latest
18z HRRR run shows what should be another round of shra/tstms
ongoing across the southern 2/3 of the CWA Wed morning. Depending
on environmental conditions, this might be a bit more convective in
nature than what we saw today. As such, higher rain rates and
saturated grounds would be a concern in regards to runoff and/or
any potential flood concerns. In addition, we may see a very diffuse
frontal boundary or wind shift in the area to work off of. Details
are still too preliminary to make blanket statements just yet...but
something to monitor in future forecasts.
Mixed messages in regards to whether this wind shift makes it off
the coast or not Wed night and takes better precip chances with
it. Prevalent sw flow aloft and any additional embedded impulses
could generate some scattered activity into Thurs-Fri if not. By
Friday night, the western upper trof should make far enough
eastern progress to allow for a slightly stronger front, and one
last round of rain, to push across the area Fri night into Sat
morning. The rest of the weekend looks dry and uneventful behind
the front. 47
&&
.AVIATION...
(00Z TAF Issuance)
Issued at 528 PM CST Mon Jan 22 2024
We are gonna see some messy flying conditions over the next few
days. For today, scattered showers will persist through this
evening, and then a brief lull in precipitation will occur during
the early overnight hours. However, expect IFR to LIFR conditions
with CIGs down to 300-500ft with patchy fog and light drizzle
bringing visibility down to 1 to 2 miles. There will be a
resurgence on showers in the predawn hours tomorrow with showers
persisting across the region through the rest of the day. There
will also be a chance for isolated thunderstorms to develop with
the best chances being north of IAH during the mid morning to
early afternoon hours. Locally heavy rainfall will be possible
with the showers and storms that may further reduce visibilities
at times. Winds will generally be from the southeast around 8 to
12kt with occasional higher gusts to near 20kt - especially near
stronger storms. The LIFR to IFR CIGs and reduced visibilities
will persist through Tuesday night.
Fowler
&&
.MARINE...
Issued at 343 PM CST Mon Jan 22 2024
Moderate onshore winds and elevated seas will persist for the next
couple days. Though speeds should be on a slow downward trend,
seas are still 10ft and will take a while to fall below 7ft. Will
maintain small craft advsy in the nearshore waters til 9pm and
the waters beyond 20nm into mid morning. A series of upper level
disturbances will move overhead into mid to late week bringing
some rounds of rainfall and isolated storms. When it is not
raining, sea fog...some dense, will be a threat with somewhat
warmer air situated over the cold nearshore waters. Fog will
remain an intermittent problem until the next front moves off the
coast later in the week. 47
&&
.HYDROLOGY...
Issued at 343 PM CST Mon Jan 22 2024
Rivers are mostly behaving themselves after today`s 1-3", isolated
4", rainfall today. There`s a few creeks that are a bit elevated
that we`ll continue to monitor for a while. No widespread
imminent problems are anticipated, though with increasing ground
saturation, we`ll need to keep an eye on things in the days to
come. Runoff with additional rounds of any moderate-heavy rain
would be an increasing concern as time evolves. 47
&&
.CLIMATE...
Issued at 307 AM CST Mon Jan 22 2024
Here are some rainfall records (and year set) for today (22nd),
Tuesday (23rd) and Wednesday (24th)...
Today (22nd) Tuesday (23rd) Wednesday (24th)
CLL: 2.90 (2015) 2.72 (1938) 2.29 (2004)
IAH: 2.52 (2019) 2.62 (1920) 4.05 (2023)
HOU: 2.35 (2015) 1.42 (1984) 2.30 (2011)
GLS: 5.38 (1923) 2.17 (1924) 2.60 (1882)
PSX: 2.66 (2015) 1.88 (1958) 2.44 (2007)
42
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 53 65 56 66 / 80 100 80 80
Houston (IAH) 59 70 62 68 / 70 80 90 100
Galveston (GLS) 58 64 60 65 / 60 60 80 90
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Tuesday morning for TXZ436>439.
GM...Small Craft Advisory until 9 PM CST this evening for GMZ350-355.
Small Craft Advisory until 9 AM CST Tuesday for GMZ370-375.
&&
$$
SHORT TERM...41
LONG TERM....47
AVIATION...Fowler
MARINE...47
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
827 PM CST Mon Jan 22 2024
.KEY MESSAGES...
* Winter Weather Advisory remains in effect everywhere north of
the I-70 corridor through this evening and north of the I-74
corridor through Tuesday morning.
* Additional ice accumulations of up to one tenth of an inch in
the advisory area.
* Above normal temperatures with periodic rain chances for the
remainder of the forecast period.
&&
.UPDATE...
Issued at 823 PM CST Mon Jan 22 2024
Next round of precipitation is overspreading central Illinois this
evening and will be in place for much of the evening and overnight
hours. Temperature and dewpoints, meanwhile, continue to straddle
the freezing mark (31 to 33 degrees) north of I-70 continuing the
threat for freezing rain. MRMS probability of subfreezing road
temps for the next hour generally runs between 40 to 70 percent
north of I-70 supporting the ongoing Winter Weather Advisory for
freezing rain despite a number of locations reporting 2m temps
just above freezing. Temperatures will generally hold steady if
not tick up a degree or so overnight. Latest HRRR/RAP runs
indicate that p-type will transition to rain south of I-74 by
midnight, and with that in mind, the southern tier of the advisory
south of I-74 appears to remain on track to expire at midnight.
With that said, it will probably be a last minute decision based
on observational temp/dew point trends to see if that will fully
or partially happen. Road conditions as reported by IDOT and other
publicly available sources indicate that slow/hazardous
conditions persist in the meantime for most of the advisory area.
Deubelbeiss
&&
.DISCUSSION...
Issued at 329 PM CST Mon Jan 22 2024
A long fetch of moisture continues to flow northward from the
Lower Mississippi River Valley this afternoon...resulting in
ongoing light precipitation along/east of the Illinois River.
Temperatures have climbed to around 32F across much of the KILX
CWA, but have pushed into the upper 30s and lower 40s south of
I-70 where little or snow cover remains. Given the surge of warmer
air, have cancelled the Winter Weather Advisory for Effingham,
Jasper, Crawford, Clay, Richland, and Lawrence counties. Further
north, light rain continues to fall onto frozen/snow-covered
ground, creating slick roadways and sidewalks. 21z RAP forecast
soundings show a pronounced elevated warm layer with maximum temps
of around 5C at KSPI and 2C further north at KBMI/KCMI. As this
layer continues to warm into the 3-5C range across the board this
evening, the warm raindrops will begin to warm surfaces and
further ice accumulations will become increasingly difficult to
achieve. Actual air temps will hover around 32F through the
evening, then will rise a couple of degrees overnight. Think
additional ice accumulations of less than one tenth of an inch are
likely south of the I-74 corridor...with around one tenth
along/north of I-74. Winter Weather Advisory will continue through
midnight for much of the area...and through 9am Tuesday across the
far N/NE CWA. Given warming at all levels of the atmosphere, think
main impacts will occur on untreated and secondary roadways, as
well as parking lots and sidewalks.
Precipitation will quickly come to an end from south to north
across the area early Tuesday morning: however, with warm/moist
air continuing to flow over the frozen ground and winds becoming
lighter, it appears a low overcast and areas of fog will prevail
throughout the day Tuesday. High temperatures will top out in the
middle to upper 30s, with lower to middle 40s south of I-70.
With the Midwest/Ohio River Valley locked into a deep-layer
southwesterly flow pattern, the next in a series of disturbances
will spread light rain back into central Illinois Tuesday night
into Wednesday. Once this wave passes, things will dry out
Thursday afternoon through Friday. The warmest day of the forecast
period will be Thursday when highs soar into the 50s along/southeast
of a Champaign to Springfield line. After that, a minor disturbance
may pass south of the region over the weekend...potentially
bringing some light rain to at least the southern half of the CWA
on Saturday. Confidence in this scenario remains low at this
point, so have only featured low chance PoPs along/south of a
Danville to Jacksonville line. Main weather story will be the
continued mild conditions as highs continue to top the 40-degree
mark right through the weekend.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 530 PM CST Mon Jan 22 2024
Light freezing rain and freezing drizzle will continue across
central Illinois through tonight, then should begin to taper off
from the southwest Tuesday morning. Southern sites (SPI/DEC) may
transition to plain rain overnight but with temps/dewpoints
straddling the freezing mark much of the night, confidence is low
on if and when this occurs. Ceilings meanwhile will drop to
IFR/LIFR if not already there and likely remain down the remainder
of the period. As precip tapers off Tuesday morning and dew points
continue to rise, fog will be possible, though minor improvement
is possible once winds veer to the SSW late morning and afternoon.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM CST Tuesday for ILZ027>031-
037-038-043>046-055-057.
Winter Weather Advisory until midnight CST tonight for ILZ036-
040>042-047>054-056-061>063.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1005 PM EST Mon Jan 22 2024
.Key Messages...
- Winter Weather Advisory for most of central Indiana for freezing
rain through Tuesday morning
- Ice accumulations of up to 0.10-0.20" in Winter Weather Advisory
area along and north of I-70
- Glaze to 0.05" ice accumulation south of I-70 in South Central
Indiana
- Fog likely Tuesday into Wednesday, possibly dense at times.
- Much warmer with multiple rounds of rain through the rest of the
week with river flooding and ice jams possible
&&
.Forecast Update...
Issued at 1005 PM EST Mon Jan 22 2024
Stubborn warm air is helping lower confidence in freezing rain
impacts, mainly in the south.
Reports of freezing rain and slick roads across the northwest
forecast area continue to come into the area this evening. These
areas are around 32 degrees with dewpoints not much lower. Expect
these conditions to persist into the overnight as more precipitation
falls.
Warm air continues across much of the southeast two thirds of the
area with temperatures in the mid and upper 30s persisting with
light south to southeast winds. Dewpoints depressions remain pretty
high, with depressions in the 10 to 20 degree range even when rain
has been falling lightly for a bit.
This warm and drier air will delay the onset of predominant freezing
rain. This may have an impact on ice amounts. In the south, overall
warmer temperatures overnight combined with the above will also have
an impact on freezing rain impacts there. However, questions remain
in how the cold ground will affect freezing on surfaces, especially
untreated ones.
Given the uncertainty, am not comfortable changing the Winter
Weather Advisory at this time. Will continue as is, but with lower
confidence. Have lowered ice amounts some though. Any ice on roads
will have an impact, as has been seen in the northwest forecast area
so far tonight.
Will continue to monitor the development closely and will make
further adjustments later tonight.
&&
.Short Term...(This evening through Tuesday)
Issued at 259 PM EST Mon Jan 22 2024
Radar returns continue to drift across the northwest half of the
forecast area this afternoon but it appears any precip that is
reaching the ground at the moment is confined to the northern Wabash
Valley. Clouds continue to thicken but the warm advection into the
region is doing work this afternoon. Temps have warmed more than
anticipated over a good portion of the forecast area likely due to
how dry the lower levels remain. Even as temps rise into the mid and
upper 30s currently...dewpoints remain largely in the teens and
lower 20s.
Model and Mesoscale Analysis...
While temps are warmer than anticipated by a few degrees this
afternoon...that does not necessarily mean the freezing rain threat
has diminished for later. As progressively deeper moisture advects
into the region over the next several hours...evaporative cooling
and wet bulbing within the boundary layer will pull surface
temperatures back to or just below freezing across much of the area
by this evening. Model guidance was struggling with precip type due
to incorrectly capturing the ground temp impacts and that has not
changed within the hi-res solutions this afternoon. Even the HRRR
now is having trouble with precip type and is likely doing what the
other models are...classifying precip type as rain with surface
temps in the 32-34 range. If we were not coming out of a deep freeze
over the last 10 days and dealing with ground frozen to a depth of
10-11 inches...this would not be an issue. However as we have
discussed over the last few days...the influence of the frozen
ground will enable efficient icing on roads and other untreated
surfaces likely until temps can warm above 34 or so.
These situations are sometime almost more dangerous because even a
small amount of precip of a few hundredths can leave a thin layer of
black ice that looks just wet and makes travel very hazardous. And
this will not be a classic icing scenario where there is concern for
power lines and trees becoming icy and falling. The bulk of the
impacts will be to the ground surfaces due to the frozen nature of
the soils.
Through Tuesday...
Precipitation will expand east into the evening as a combination of
freezing rain and rain but ultimately the northern 2/3 of the
forecast area are still in line to transition to predominantly
freezing rain for several hours into early Tuesday. Expect
temperatures to drop into the 30 to 33 range this evening into the
early overnight before slowly rising late tonight and Tuesday
morning from the south as warm advection strengthens.
Should see a gradual transition to rain in most areas south of I-70
by 12Z Tuesday with improvements further north not occurring until
after daybreak. Most of the precipitation will fall from the predawn
hours through early afternoon Tuesday before the deeper moisture
shifts off to the east. The boundary layer however will remain
saturated with a thick...low stratus deck for the afternoon and the
potential for increasing visibility restrictions as fog forms with
warmer air overtop of the lingering frozen ground. This is likely to
become a bigger issue for Tuesday evening and night prior to a
resumption of more widespread rain and will be addressed further in
the Long Term discussion below.
Headlines...
No changes to the Winter Weather Advisory will be made with the
afternoon forecast package. The decision to move the headline start
times forward by several hours earlier today was made due to the
eastward extension to the initial wave of moisture impacting the
Wabash Valley and the arrival of the second and broader wave of
moisture this afternoon. For simplicity...the eastern segment to the
Advisory was started earlier as well although the bulk of the
impacts will hold off for most areas along and east of I-69 until
this evening and beyond. Expect the primary impacts will come this
evening after dark continuing through daybreak Tuesday...especially
along and north of I-70. Overall amounts falling as freezing rain
will range from a few hundredths over southern portions of the
forecast area to 0.10-0.20 inches north of I-70. Highest icing
amounts will focus near Lafayette and the northern Wabash Valley
which have already seen light icing earlier today.
Temps...
As mentioned above...we were expecting much of the area to warm
above freezing this afternoon but rises have outpaced model
projections in general by a few degrees. Still anticipate temps fall
back into the lower 30s this evening as evaporative cooling and wet
bulbing processes take place within the boundary layers. Temps then
should remain steady or slowly rise overnight in response to the
warm advection. Highs on Tuesday will range from the upper 30s to
the mid 40s.
&&
.Long Term...(Tuesday night through Monday)
Issued at 259 PM EST Mon Jan 22 2024
The primary forecast challenge through the long range is the
potential for dense fog Tuesday evening into Wednesday, and for ice
jams and associated river flooding. Additionally, periods of
rainfall are possible at times this week.
SYNOPTIC OVERVIEW
Split flow currently exists across the CONUS in the upper levels.
The just stream splits over the west coast, with northern stream
ridging situated on top of southern stream troughing. The southern
stream trough resides over the Four Corners region, and combined
with ridging over the southeast US...our position relative to these
two features places us within broad southwesterly flow.
As such, the persistent arctic air mass that has been in place for
the past 10 days is quickly eroding away. It will be replaced by a
much warmer and wetter air mass originating out of the Gulf.
This flow pattern should persist for the majority of the week, with
a bit of a shift occurring over the weekend. Split flow aloft will
remain, though the northern stream ridge becomes the more prominent
feature placing us within northwesterly flow aloft towards the end
of the period.
WEATHER HAZARDS AND EXPECTED IMPACTS
The first potential impactful weather is dense fog beginning
tomorrow and continuing into Wednesday. Fog will be advective in
nature, as a warm moist air mass advances over still-frozen ground.
Any lingering snowpack could exacerbate the effect. Fog may become
dense at times, and potentially widespread.
Second, periods of rain will be likely at times this week.
Isentropic lift associated with the moist warm advection combines
with forcing from embedded shortwaves aloft. Guidance shows two
waves in particular which are expected to each bring a heavier round
of rainfall. One arrives Wednesday and another is expected on
Thursday, though the Thursday wave may pass largely to our south and
east. Combined with another wave on Tuesday...weekly precip totals
may end up between 1 and 2 inches.
This rainfall over frozen ground may lead to enhanced runoff and
localized flooding/ponding of water. Additionally, frozen rivers
begin to break up and ice jams are possible at times as
well...leading to additional flooding potential.
FORECAST CONFIDENCE
Confidence is high in the overall pattern through the week. Ensemble
forecasts remain locked in on the southwesterly flow and associated
moisture advection. In fact, NAEFS/ECMWF ensemble situational
awareness tables remain at or over the 99th percentile in terms of
available moisture and 500mb heights. GEFS spaghetti plots remain
tightly clustered through Saturday. Strongly positive
teleconnections add weight to the idea of a warm pattern continuing.
Confidence for fog and rainfall amounts are moderate, as some
questions remain regarding areal extent and thickness/intensity.
Regardless, both appear likely for portions of the CWA at the very
least.
Regarding ice jams and flooding, confidence is high of ice jam
occurrence because we have already seen a few within the CWA. More
are likely to occur as melting/breakup accelerates. Confidence in
flooding is moderate, since the ice jams we have seen have yet to
cause any flooding. Though a few spikes in the hydrographs have been
noted as a result...these have remained under flood limits. With the
added rainfall and melt this week, that may change.
&&
.Aviation...(00Z TAF Issuance)
Issued at 614 PM EST Mon Jan 22 2024
Impacts:
- Freezing rain will become widespread at all terminals this
evening
- Gradual transition to rain from south to north Tuesday morning
- IFR and lower ceilings developing predawn Tuesday and persisting
through the end of the forecast period
Discussion:
Light freezing rain will continue at KLAF. At the other sites,
precipitation will overspread them during the evening. Initially
there could be rain with temperatures starting above freezing, but
cooling will occur and transition to all freezing rain during the
evening.
Freezing rain will continue during the night, and a transition to
rain will occur from south to north during Tuesday morning.
Confidence in the timing of transition is medium at best.
Flying conditions will deteriorate through the period, with IFR and
worse expected for Tuesday. Dense fog may develop toward the end of
this period and for the KIND 30 hour TAF.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM EST Tuesday for INZ021-
028>031-035>049-051>057-060>065.
&&
$$
Update...50
Short Term...Ryan
Long Term...Eckhoff
Aviation...50
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1007 PM EST Mon Jan 22 2024
.UPDATE...
Issued at 1007 PM EST MON JAN 22 2024
Challenging forecast this evening. Questions persist on how cold
it will get tonight and what time precipitation arrives tomorrow.
Latest run (0Z) of the hrrr and nam both keep our area precip
free through and until tomorrow afternoon at the earliest.
Temperatures fell quickly through the evening but have leveled off
since. Coldest temperatures are found in areas where decoupling
(very light or no winds) has taken place, sheltered valley
locations are in the mid 20s. Otherwise, thermal belt temps have
been very slow to drop, still around 40 or higher at this hour.
Temperatures are still expected to respond to increase in cloud
cover later tonight, from west to east. Western areas will reach
their lows sometime after midnight, but a little later in the
east. We are already seeing signs of leveling off, even a rise in
a couple places. Expect this up and down will continue for several
more hours before rising solidly through the pre-dawn time frame.
While fairly confident we will not see precipitation before
temperatures have risen above freezing in the morning, can not
guarantee no precipitation. Thus will allow the SPS for the
possibility of light freezing rain across our northern zones to
continue. Incoming shift will be able to digest the full suite of
0Z output before making a decision on whether to continue it
through tomorrow morning.
Will update the zones to freshen up wording, bring grids in line
with latest obs, and possibly tweak our overnight lows up slightly
across the thermal belt and locations where winds are strong
enough to keep the boundary layer mixed out and in turn
temperatures up. May drop our coldest valleys a degree or two
more since a couple locations are approaching or have already
reached advertised lows.
UPDATE Issued at 750 PM EST MON JAN 22 2024
No major changes to the forecast at this time. Main adjustments
were to hourly temperatures. A light southerly gradient is helping
to keep temperatures up, with the exception being our colder
sheltered valley locations. Here temperatures have dropped
precipitously and have already fallen into the upper 20s. Clouds
will be on the increase overnight, lowering and becoming thick
enough to influence surface temps during the pre-dawn hours. Thus
expect our lows to be hit shortly after midnight in the west, a
bit later in the east, with a leveling off and increase thereafter
from west to east as the more substantial cloud cover overspreads
the forecast area. Just the same, may wind up having to drop
overnight lows just a bit more for our typically colder valley
locations.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 334 PM EST MON JAN 22 2024
Key Points:
* An approaching disturbance brings a low end threat of freezing
rain in deeper valleys early 6Tuesday morning, mainly near and
north of I-64.
* Warming temperatures Tuesday morning will allow precipitation to
transition to all rain, with scattered to widespread rain showers
forecast through the remainder of the period.
* Temperatures are expected to continue on their incline, with above
average values anticipated Tuesday.
It has been a quiet and an overall warmer day across Eastern
Kentucky, with early afternoon temperatures varying from the mid 40s
near the TN border to the upper 30s under departing cloud cover in
the far northeast. Regional satellite, along with local obs, depict
high clouds passing through the area now, with lingering snow on the
ground across much of the area. The latest surface analysis
highlights high pressure centered near the Outer Banks. Return,
southerly flow, has given us a boost in temperatures today, with a
few more degrees higher likely before entering this evening. Those
under cloud cover, generally along the Mountain Parkway, should see
the greatest increase over the last couple of hours of peak heating.
Through the short-term period, guidance is in fairly good shape.
Starting aloft, a stout ridge is centered just east of the
Caribbean, with its ridge axis extended through the Ohio River
Valley. This will generally rule aloft through the short term
period, though a ridge riding shortwave will progress from the
Southern Plains to Great Lakes tonight to Tuesday night. With a tap
into better moisture out of the Gulf, chances for precipitation will
begin to overspread the area from the west early Tuesday morning.
There is some low end concerns for freezing rain, particularly in
deeper valleys, near to just after sunrise. With clearer skies,
particularly in the east, expected this evening into early tonight,
sheltered valleys will fall quickly. That said, with cloud cover
thickening up tonight into Tuesday, low temperatures along and west
of the Mountain Parkway are likely to slowly rise the later half of
the night. CAM`s have trended slower in the progression of the
system, with measurable PoP (20-30%) not arriving in the Bluegrass
to Cumberland Basin until near dawn. As such, the confidence in
freezing rain is low but not entirely ruled out- specifically near
and north of I-64. The concerns come with two main caveats. One- if
the timing in PoP arrives sooner the concern would be larger, while
the current forecast (or even a slower trend) should largely
mitigate the risk. Two- lingering snow and/or ice on the ground.
With temperatures across the CWA well above freezing this afternoon,
snowpack melting is expected. However, as temperatures fall below
freezing into tonight, lingering moisture on roadways could freeze
causing some slick spot and could impact ambient temperatures during
initial precipitation. Thus, localized freezing rain is possible in
deeper sheltered valleys or common cool spots (bridges/overpasses).
Have covered this threat with an SPS from a line from Estill Co to
Elliott Co and north early Tuesday morning.
Any early morning freezing rain will diminish to all rain with
warming temperatures Tuesday morning. PoP will be highest in the far
west/northwest coinciding with a nosing ~925mb 30-40 kt jet. As this
departs north into Tuesday afternoon, shower chances diminish across
the SE and will stay confined to the chance category mainly along
and north of the Hal Rogers Parkway into Tuesday night. A deeper
wave out of the Southern Plains will then slide east, where a
supported surface low and building warm front approach at the end of
the period. Shower chances will increase from NW to SE ahead of this
next approaching system into the pre-dawn hours of Wednesday. As
with highs, low temperatures Tuesday night will fall to above late
January norms, in the upper 30s to low 40s.
.LONG TERM...(Wednesday through Monday)
Issued at 623 PM EST MON JAN 22 2024
Key Messages:
- A prolonged wet period through the end of the week.
- Moderate to heavy rainfall midweek with flooding possible.
- Well above normal temperatures through Saturday.
- Colder the second half of this weekend and early next
week...but still near normal for late January.
Broad troughing will start out positioned over the central and
southern Rockies, with southwest flow in place through the
Mississippi, Ohio, and Tennessee valleys. A lead short wave
trough will very gradually lift east northeast through the middle
Mississippi Valley Thursday and then the Ohio Valley into Friday.
The trough will then get reinforced over the Plains, as stronger
short wave energy digs in from the eastern Pacific. A low will
cutoff over the southern Plains and then moves east northeast
through the Ohio Valley early this weekend, before exiting off to
the East by Sunday. This will result in a prolonged period of wet
weather across eastern Kentucky, with well above normal
temperatures. Northwest flow will follow into early next week,
with colder air returning with some light upslope snow, although
temperatures will be near normal by late January standards.
Climatologically very high PWATs (99th percentile or greater)
will build in across our area through mid-week, as intermittent
moderate to strong 850 mb jet streaks pump in this moisture
continually through the period. Widespread rain moves in Wednesday
through Thursday night, with the heavier amounts generally
falling from late Wednesday afternoon through early Thursday
morning, and then picks up once again Thursday night, as a cold
front passes through the region. There is still plenty of model
spread regarding rainfall amounts and where the axis of heaviest
rainfall aligns. For now, have allowed for a blend of the majority
of the guidance to dictate the forecast amounts, generally 1.5 to
3 inches, with higher amounts nearer the Tennessee and far
southwest Virginia borders, and lesser amounts closer to the I-64
corridor.
Model guidance does continue to support some pockets of instability
at times through this period. Thunderstorm placement becomes more
critical for the higher rainfa6ll totals and those inevitable
potentially higher amounts of greater than 3 inches. At this
time, there appears to be a somewhat better chance at this
occurring near the Cumberland River Basin, particularly the lower
portion, making this area more susceptible to creek and stream
flooding, and eventually some river flooding, should the
precipitation amounts materialize. Given the saturated soils that
will be in place leading into this event, runoff will be
particularly efficient. On the other hand, streams across the
entire forecast area are running below to well below normal for
this time of year, which helps. Given the ingredients at play
here, have hoisted a Hydrologic Outlook for most locations south
of I-64, with more emphasis on the Cumberland River Basin. Will
await the HREF guidance tomorrow to see how much of the convective
component evolves regarding the potential for better rainfall
totals for Wednesday evening.
A cold frontal passage will bring a temporary end to the steadier
rains early Friday morning; however, as the next mid-level low and
surface low gen up across the Ark-La-Tex region and lifts
northeast, another round of moderate to perhaps briefly heavy
rainfall occurs Saturday into Saturday night. There is even more
uncertainty with this second rainfall event, still being several
days out, but the model guidance has been fairly consistent with
showing this round as more progressive in nature, and PWATs would
be lower by that time. As such, the rainfall may wind up either
just slowing receding river flows or resulting in a secondary
rise, but more likely of a lesser magnitude. As this system pulls
away Sunday into Monday, colder air will move in on northwest
flow, with a chance of some light snow hanging on the more favored
upslope areas over southeastern Kentucky into early next week.
High temperatures will average well into the 50s each day through
Saturday, with the warmest overall day looking like Thursday, as
temperatures top out in the lower 60s. Highs will then retreat to
the 40s by Sunday and Monday.
&&
.AVIATION...(For the 00Z TAFs through 00Z Tuesday evening)
ISSUED AT 750 PM EST MON JAN 22 2024
With the exception of KSYM, VFR conditions are expected to
prevail through much, if not all, of the forecast period. A
passing upper level disturbance will look to bring increased
cloud cover tonight through Tuesday, with CIGS gradually lowering
into Tuesday. Winds aloft will increase into tonight as well, as
a 30-40 kt LLJ takes shape. This will pose LLWS concerns across
mainly western sites (SME, LOZ, and SYM) late this evening and
through part of the day Tuesday. Showers will also begin to
develop across the area through the day Tuesday. Went with a
prevailing weather group for SYM...rain by mid-day Tuesday, and
generally VCSH elsewhere. Winds will remain 10 kts or less
through the period, mainly from a south-southeast direction.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...BB
LONG TERM...GEOGERIAN
AVIATION...BB/RAY
Area Forecast Discussion
National Weather Service North Platte NE
536 PM CST Mon Jan 22 2024
.KEY MESSAGES...
- A dense fog advisory is in effect tonight through Tuesday
morning across all of western and north central Nebraska. With
temperatures falling below freezing, slick spots may develop
in areas of dense fog, especially on elevated surfaces.
- Fog concerns continue Tuesday night into Wednesday, with dense
fog expected, especially across the south and west.
- Mainly slight chances for light rain across the far southeastern
zones Wednesday, with light freezing rain possible in the
morning.
- Quieter weather conditions and a return of near to above
average temperatures Thursday through Monday, with upper
ridging amplifying over the Rockies.
&&
.SYNOPSIS...
Issued at 325 PM CST Mon Jan 22 2024
Temperatures have reached or exceeded 50 degrees across
portions of western Nebraska. North Platte had reached 50
degrees and Imperial 51 degrees at 3pm CST. O`Neill remained
colder at 30 degrees. Skies were sunny to mostly sunny. Stratus
and fog were widespread to our southeast mainly east of a line
from Norton KS through Kearney and Wayne NE.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 325 PM CST Mon Jan 22 2024
A backdoor cold front will drop southward into the area tonight
as low level moisture is advected into the area. The latest
mesoscale models HRRR and RAP as well as HREF ensemble
probabilities all support areas of dense fog/freezing fog
across all of western and north central Nebraska. Some weak lift
would also support a slight chance for freezing drizzle later
tonight into Tuesday morning across central and southwest
Nebraska. A Dense Fog Advisory has been issued for all of
western and north central Nebraska tonight through Tuesday
morning. Slick spots on elevated surfaces are tonight as
temperatures fall below freezing in the overnight hours.
Areas of dense fog and freezing fog, possibly light freezing
drizzle will linger Tuesday morning as stratus will persist into
the afternoon. This will keep temperatures on the cool side
mainly in the mid 30s.
A southerly flow in the lower levels Tuesday night will
maintain moisture advection. The HREF ensemble probabilities
again support the likelihood for fog development. Dense
fog/freezing fog is possible, especially across the south and
west. Lows not as cold in the mid 20s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 325 PM CST Mon Jan 22 2024
Fog is expected to continue Wednesday morning. A Southern
Stream system will lift northeastward Tuesday night across
Kansas and across central and eastern Nebraska Wednesday into
Wednesday evening. Mainly a slight chance for light rain,
possibly light freezing rain Wednesday morning. With expected
stratus and fog, highs Wednesday mainly 35 to around 40.
As moist low level advection persists atop lingering snowpack,
fog will again be possible Wednesday night into Thursday
morning. With clearing from west to east through the day, highs
Thursday from the mid 30s northeast to the low to mid 40s west
and southwest.
Patchy slick spots on elevated surfaces are possible each night
into the morning hours, as temperatures fall below freezing in
the overnight hours.
By Friday and Saturday, the upper trough is expected to be
positively tilted from the Central and Southern Plains across
the Great Lakes. While dry conditions are expected, some
cloudiness will persist with highs near to above seasonable in
the mid 30s to mid 40s (warmest across the west).
Sunday and Monday, dry conditions as upper ridging builds
across the Rockies with northwest flow to the east across the
Northern and Central Plains. The colder airmass will remain well
to our east across the Great Lakes and Ohio Valley. Highs
across western Nebraska are likely to range in the upper 40s
Sunday and even some low 50 Monday.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 522 PM CST Mon Jan 22 2024
A deep low-level cloud deck will encompass the area in the next
few hours resulting in rapidly deteriorating aviation
conditions bringing IFR/LIFR ceilings to all terminal sites. In
conjunction with the low-level clouds, fog will develop late
this evening and continue into the morning on Tuesday.
Visibility restrictions down to 1/2SM are likely with some
locations seeing visibility down to 1/4SM or lower. Fog will
begin to lift back Tuesday afternoon, though the low ceilings
(below 700 ft) persist for much of the area. Shortly after the
valid period, very low ceilings and widespread dense fog returns
for all of the area, impacting KLBF and KVTN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until noon CST /11 AM MST/ Tuesday for
NEZ004>010-022>029-035>038-056>059-069>071-094.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Viken
Area Forecast Discussion
National Weather Service Pittsburgh PA
932 PM EST Mon Jan 22 2024
.SYNOPSIS...
Freezing rain is possible in eastern Ohio and north of
I-70 in Pennsylvania and West Virginia for the Tuesday morning
commute. Intermittent rain chances and a warming trend is expected
into late week with river rises into the weekend.
&&
.NEAR TERM /THROUGH TODAY/...
KEY MESSAGES:
- Up to a tenth of an inch of ice accumulation is possible through
tomorrow morning in freezing rain for the area highlighted by a
Winter Weather Advisory.
---------------------------------------------------------------
Added some low PoPs for light initial activity north of I-80,
which is likely having trouble becoming measurable with T/Td
spreads still around 20 degrees. This initial activity may fall
as snow or very light freezing rain/drizzle, followed by a brief
break before the main precipitation shield arrives later.
Earlier, the main changes to the overnight forecast included
pushing precipitation onset a touch later and a touch further
north than the previous forecast. Much of the hi-res model
guidance like the HRRR and NamNest have been showing a slight
northward shift in the precipitation footprint across the
region, not surprising given the low-level dry air in place, and
the fact that modest forcing for ascent remains mainly north of
Pittsburgh. There is still little doubt that the vast majority
of the precipitation that arrives past 06Z will be in the form
of freezing rain. This notion is reinforced by the fairly
substantial warm layer that is already present on the 00Z PBZ
sounding between 925mb and 800mb, and by the cold surface still
in place after nine days of subfreezing temperatures. For now,
little adjustment was made to event ice totals, and the ongoing
Winter Weather Advisory remains in place. Still, confidence in
ice accretion totals in the southern portion of the advisory
area, particularly in the I-70 corridor, remains low overall.
Previous discussion...
The east coast remains under the influence of high pressure as upper
moisture advection increases clouds into this evening. Westerly to
southwesterly flow aloft will continue to bring in higher
moisture, warmer air from the southeastern CONUS. These two
factors will come together to maintain dry, above average
temperatures tonight in the low-levels, with saturated
conditions above roughly 800mb.
An area of mid-level ascent ahead of a passing shortwave low
will generate precipitation aloft, most likely in eastern Ohio
and north of I-70 in Pennsylvania and West Virginia. The main
question with this initial wave will be 1) the positioning of
it, and 2) whether precipitation is able to make it through the
surface dry layer. Should precipitation occur and make it to
the surface before roughly 9am, it should have no issues
accruing on surfaces given cold surface temperature after the
recent cold snap, even if air temperatures are slightly above
freezing. Both of these factors remain more likely north of US
Highway 22 in eastern Ohio in the northern Panhandle of West
Virginia, as well as north of the Pittsburgh metro in western
Pennsylvania.
In the area immediately south of this, including the Pittsburgh
metro, confidence in ice accretion lowers with the initial
precipitation wave. It is missed by the strongest forcing and
precipitation will fight low-level dry air. Given the high-impact,
low-confidence forecast, opted to go south with the Winter Weather
Advisory to cover ANY areas that my be potentially impacted. If
this secondary area is missed by the initial wave, it is more
likely to be hit with a precipitation onset time in the late
morning and afternoon; this will fall as rain. This adds a good
bit of uncertainty in the ice accretion forecast for this area.
Morning freezing rain will transition to scattered afternoon rain
showers with high confidence. Temperatures will warm to seasonable
averages, keeping any travel impacts limited-to-none for the evening
commute. Additional QPF in rain will remain less than 0.10".
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:
- A wet period with above average temperature will prevail.
---------------------------------------------------------------
The initial push of moisture on a shortwave will depart early
Tuesday night, followed by unsettled weather with saturated low
levels in a transition zone ahead of the next passing
disturbance into the day on Wednesday.
Probabilities of QPF accumulations greater than an inch are
generally less than 25% for this period. Around 0.5" of accumulation
is more likely, with the highest potential for accumulations
exceeding this south of I-70.
Temperatures will continue to moderate with temperatures 15-20
degrees above average and PWATS near all-time record levels.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
KEY MESSAGES:
- Temperatures warm up through the end of the week
- River rises are increasingly possible by late week
- Unsettled pattern with rain chances continues through the weekend
---------------------------------------------------------------
Unsettled weather with an amplified pattern will continue into the
weekend with a persistent upper trough situated across the central
CONUS. The trough will gradually flatten a building, but weak, ridge
axis overhead and maintain rain chances to close out the week as a
couple rounds of low pressure track up the East Coast.
The first one looks to ride through the Great Lakes on Thursday and
provide perhaps our best chance for widespread rainfall and the
warmest temperatures of the week. QPF amounts from Thursday through
Friday night range from around a tenth of an inch on the low end to
an inch on the high end. NBM probabilities of exceeding 55 degrees
on Thursday reach 70-90% areawide, save areas north of I-80.
This final wave is most likely to fall on the existing
snowpack, bringing snowmelt and QPF downstream in high-PWAT,
warm air. This will bring hydrological concerns to rivers
through the late-week and weekend period. The OHRFC forecast has
a fairly widespread 30% probability of many gauges reaching
action stage.
Another upper wave diving into the central CONUS will reinforce the
trough into the weekend as another low pressure system develops,
though uncertainty amongst the ensembles with the strength of the
trough and ridge lends lower confidence in rain chances for the
latter half of the weekend, so stuck with chance NBM PoPs through
Sunday.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Moisture transport is strongest currently through AR MO IL and
northern portions of IN into NW Ohio. Clouds are spreading
across northern Ohio and expect VFR ceilings to spread across
area during the night in warm advection regime. Therefore
confidence is highest that moisture will return to northern
ports first before sinking south Tuesday and Tuesday night.
Temperatures are currently near or above freezing but dewpoints
are in the teens so wet bulb cooling with turn any precipitation
to freezing rain when it arrives late tonight and early Tuesday.
High confidence in freezing rain with glaze accumulations to
about a tenth of an inch at FKL and DUJ. Precipitation could mix
with sleet and snow during the morning in those areas but
freezing rain will be primary precipitation type. Freezing rain
also likely at ZZV and BVI. Farther south possibility of
freezing rain at the ports with exception of MGW where it will
remain dry until late afternoon when temperatures have warmed
well above freezing.
Precipitation will eventually transition to rain by the midday
hours. However, given the recent cold spell, roadway sfc
temperatures will likely lag air temperatures rising to above
freezing by 2-4 hours.
.OUTLOOK...
Restriction potential will persist through the week with
persistent low/mid-level moisture and periodic disturbances
crossing the region. IFR to LIFR ceilings and IFR visibilities
are likely Wednesday and Thursday due to rain and fog with
melting snow cover enhancing the potential for fog.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 1 AM to noon EST Tuesday for
PAZ007>009-013>016-020>022-029-073-077-078.
OH...Winter Weather Advisory from 1 AM to noon EST Tuesday for
OHZ039>041-048>050-057>059-068.
WV...Winter Weather Advisory from 1 AM to noon EST Tuesday for
WVZ001>003.
&&
$$
SYNOPSIS...Milcarek
NEAR TERM...CL/Milcarek
SHORT TERM...Milcarek
LONG TERM...MLB/Milcarek
AVIATION...Craven
Area Forecast Discussion
National Weather Service Pocatello ID
257 PM MST Mon Jan 22 2024
.SHORT TERM...Today and Tuesday.
Currently, the flow aloft is southwesterly. Moisture from a
filling upper level low will move over our area tonight through
early Wednesday morning. This trough/wave coming through tonight
will bring mostly south southwesterly flow to the area, especially
favoring the southern Central mountains and the Montana Divide.
Look for 1 to 3 inches with up to 4 to 5 inches for higher
elevations for these areas today through Tuesday. Look for around
1 inch elsewhere mainly above 5500 feet through early Wednesday
morning.
Temperatures will continue to be above normal with highs in the 30s
to near 40 in the valleys. The valleys will continue to see
overnight lows falling to near or below freezing. With melting/rain
falling during the day, the threat for untreated surfaces refreezing
at night will continue. Our western areas like the Eastern Magic
valley, Shoshone, and the Sun Valley region could see freezing
rain tonight. However, the chance is low. Precipitation starts
earlier, around midnight. With cloud cover temperatures may not
drop below freezing. The best chance of freezing rain Tuesday
morning will be across the Arco Desert and Upper Snake Plain
around 4 to 10 am when rain moves into the area and temperatures
have had a chance to drop below 32 degrees. Wednesday morning most
of the precipitation will be exiting our eastern areas where
temperatures will likely be low enough where all precipitation
will be snow.
TW
.LONG TERM...WEDNESDAY THROUGH NEXT MONDAY...
An unsettled, moist, showery, mild airmass will remain in place
across SE Idaho throughout the rest of the week and into next
weekend, with one more organized shortwave trough on the menu. This
feature will push through late Wed night through Thu and Thu night,
"focusing" another round of more organized rain/snow shower
activity. With winds trending from S to NW over the course of this
trough, precip will favor the mntns, especially across the srn/ern
highlands, with very marginal temps yet again supporting a mix of
rain and snow depending on time of day and location. Overall QPF
amounts continue to look modest with this system, with perhaps a
light coating of snow in the valleys and 2-4 inches in the srn/ern
highlands. We`ll have to continue watching for freezing rain
potential as well in the Snake Plain corridor and adjacent valleys,
similar to the last few days. Daytime high temps will continue to
live in the 30s throughout the week, with both highs/lows perhaps
losing a few degrees for Fri and Sat as we see a weak frontal
passage with this shortwave. From Fri through the weekend and into
early next week, both 500mb height cluster analysis and the long-
range deterministic models continue to support amplifying high
pressure ridging becoming the dominant synoptic feature for our area
(which would support drier conditions and a slight warming trend),
while all of these guidance sources also continue to hint at
significant moisture passing VERY close to our CWA, especially the
Central Mntns. Any given day, at least one cluster of ensemble
members (as high as 30% of the total ensemble space) leans wetter
than the multi-model mean for at least western portions of the CWA,
with one cluster even inching a 0.10" QPF line into the Central
Mntns, and deterministic models bring significant waves of moisture
crashing into the PacNW coast on the west side of the ridge
throughout the period (generally "washing out" before making it this
far east). SO...looking at about a 30% chance scenario of continued
shortwave/moisture penetration, and about a 60% most likely scenario
of more organized/sustained drier wx...a break!
KSmith
&&
.AVIATION...
An unsettled, moist, showery, mild airmass remains in place
across SE Idaho, with our next shortwave trough forecast to cross
the region tonight and Tue. This trough will serve to "focus" a
period of more organized, predominant rain/snow within the overall
showery pattern. Tweaked start times just slightly in some of the
12z TAFs based on the latest HREF suite of CAMs...with snow
arriving at KSUN around 04z/9pm, and then spreading across KBYI,
KPIH, and KIDA from west to east between 07-11z/12-4am. Temps will
be VERY marginal and near freezing, with a slight proclivity to
favor slightly warmer air just above the sfc, which may support
some FZRA at these 3 latter terminals. HREF probability of
freezing rain generally ranges from 20-40%, close to or slightly
lower than earlier guidance, but all data considered including
forecast soundings, and given that mixed precip continues to be
advertised by the NBM, we have absolutely no confidence in
suggesting the risk has abated and continue to carry FZRA in the
TAFs via TEMPOs at KBYI/KPIH, and via a predominant group at KIDA
as sfc temps will be slightly colder there. (Also, we HAVE seen
brief instances of freezing rain/drizzle in this pattern over the
past 2 days.) The risk will continue for much of the AM, ending
last at KIDA toward noon or 1 PM Tue assuming sfc temps warm as
forecast and change everything to rain. Regarding cigs/vsbys, NBM
guidance has performed VERY poorly in this moist airmass, and
consensus/consistency with MOS and HRRR guidance hasn`t been good
either, making cigs/vsbys very difficult to forecast. Confidence
in these elements is low throughout the entire forecast period,
but especially so for this next round of precip tonight/Tue. We`ve
been leaning a bit more optimistic/less impactful than the doom
and gloom of the NBM (and looking closely at the HRRR) for exact
numbers, while trying to capture the trends and timing as best we
can. In general, IFR conditions are forecast coincident with the
arrival of precip, continuing throughout much of the day Tue if
not right through Tue night, although perhaps improving after
17z/10am at KSUN as impacts shift east. Winds look very light
throughout the period (higher confidence there). Regarding KDIJ,
it`s possible organized precip and attendant cig/vsby reductions
move in at some point Tue, but so far many high-res models hold
the most organized activity west of the terminal, so stay tuned on
that.
KSmith
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Sacramento CA
212 PM PST Mon Jan 22 2024
.Synopsis...
A break in the weather is expected Tuesday before a less
impactful weather system moves through late Tuesday night and
Wednesday bringing another round of valley rain and mountain snow.
Another weak system will influence at least the northern half of
the region Friday into Saturday, with dry conditions Sunday.
&&
.Discussion...
As of 1:30pm, lingering cloud cover has inhibited the thunderstorm
development so far this afternoon. Mesoanalysis and latest runs
of the HRRR indicates that some isolated showers may develop along
the Coastal Range, quickly fizzling out as they move off
eastward. Given the heaviest rainfall has since ended and the
latest trends, decided to cancel the Areal Flood Watch.
Dry conditions will return for Tuesday. With increasing heights
providing little wind/mixing and very saturated grounds from
previous storms, expecting either dense fog to develop across the
Central Valley or significant low stratus. Aired on the side of
caution and just went with a valley-wide Dense Fog Advisory for
1AM-9AM Tuesday to capture the potential fog impacts so commuters
can plan accordingly and drive with caution tomorrow morning.
By Wednesday, a less impactful and quick-hitting storm will bring
more light precipitation across the region. Forecast amounts are
not expected to bring significant impacts, with storm totals of
generally remaining below 0.25" for much of the Valley, though
heavier amounts are possible near Redding, where around 0.50" is
possible for the 36 hour storm total. As usual, higher amounts are
possible in the foothills and mountains, with 0.50-1" total.
As the shortwave exits east Thursday afternoon, heights will
increase and dry northwest flow will provide another brief break
before yet another weak storm influences at least portions of our
region late week into the weekend.
//Peters
&&
.EXTENDED DISCUSSION (Friday THROUGH Monday)...
On Friday, upper level ridging still dominates the synoptic
pattern but moisture associated with an AR that is forecast to
impact the PacNW will glance over the area. This will allow for
slight chances of precipitation for the northern Sac Valley,
mainly north of Yuba City, and for the Sierra and southern
Cascades lasting through Saturday night. Right now the National
Blend of Models (NBM) has around a 20-50% probability of exceeding
0.50" inches of rainfall in the aforementioned areas through
Sunday morning. Confidence is still relatively low on rainfall
amounts, so stay tuned for forecast updates as we move through the
week. Monday we look to dry out with no forecast precipitation
for the area thanks to the upper-level ridging.
While the area is under the influence of high pressure and rising
heights, and as precipitation moves out of the area, temperatures
are forecast to rise above climatological normals as we move into
the weekend. Valley high temperatures on Saturday will be in the
upper 50s and on Sunday and Monday, the Valley will climb into the
mid 60s.
&&
.AVIATION...Areas of MVFR with afternoon and evening showers in
the Valley through 21Z and lingering in mountains through 14Z.
Possible isolated thunderstorms in the Sacramento Valley from 21Z
thru 03Z Tuesday. IFR/LIFR conditions possible due to fog from 06Z
thru 18Z Tuesday. Light winds across the forecast area outside of
gusts up to 15 kts in the Northern San Joaquin Valley through 18Z
Tuesday. &&
.STO WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory from 1 AM to 9 AM PST Tuesday for Carquinez
Strait and Delta-Central Sacramento Valley-Motherlode-Mountains
Southwestern Shasta County to Western Colusa County-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Southern Sacramento Valley.
&&
$$