Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/30/19
Area Forecast Discussion
National Weather Service Caribou ME
910 PM EDT Sun Sep 29 2019
High pressure will build across the state tonight into Monday.
A warm front will lift north into the region on Tuesday into
Tuesday night, followed by a cold front on Wednesday. High
pressure will build in on Thursday into early Friday.
.NEAR TERM /THROUGH MONDAY/...
9 PM Update...The wind is diminishing overland and valley temps
are beginning to cool faster than surrounding area so adjusted
temps a bit. Otherwise, no major changes this hour.
The Frost Advisory remains in place for the Maine Central
Highlands to the Downeast coast.
Confidence is high that a hard freeze is in store across the
north and west with frost as far s as the coast. High pres is
expected to build into the region overnight. Clouds across the
north are starting to dissipate as the dry air continues its
trek into the state. Looking for clear skies overnight and winds
dropping off the high presses east. Temps are expected to drop
off quickly after sunset. The question is whether the winds will
decouple enough for widespread frost. The latest RAP and NAM
show winds decoupling enough for the potential for frost.
Interestingly enough, the GEM tries to keep a wind around 5 mph
or so, especially across the eastern 1/2 of the CWA. This would
keep the blyr mixed enough to prevent widespread frost. Decided
to stay close to the previous thinking w/winds dropping off
below 5 mph after 1-2 AM, which should be enough time for frost
to develop. Some sites across the n and w, especially in the
river valleys will see mid/upper 20s by daybreak. The potential
for river valley fog is there. Tried to play for this in the
Monday will see a good deal of sunshine after a cold start.
Winds will be light averaging around 5 mph. Increasing clouds
from the west by late in the afternoon. Daytime temps will be
tad warmer than today, but near normal for the last day of
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Warm front approaches from the west Monday night with increasing
clouds. Still enough clearing and light enough winds earlier in
the night for most areas to decouple and cool off to the mid 30s
to low 40s. Not as cool as Sunday night though. For Tuesday,
warm front moves through with light rain, mainly in the
afternoon and mainly in the north, though there is a chance of
rain Downeast as well. Rather juicy airmass behind the warm
front Downeast late Tuesday into Tuesday night with dewpoints
rising to near 60. Can`t rule out a few thunderstorms Downeast
late Tuesday into Tuesday evening, but didn`t have the
confidence to put them into the forecast. Tuesday night, surface
low passes north of us from west to east, and as this occurs,
drags a cold front through Maine from north to south. Good shot
at rain as the front moves south through the night, but rain
doesn`t look very heavy as upper level dynamics aren`t
impressive with ridging aloft just to our west. Cold front
appears to push offshore Wednesday with cooler, drier airmass,
though some model ensemble members hang up the front enough near
the coast to where can`t totally rule out some rain Downeast.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Wednesday night into Thursday looks mostly dry and cool with
high pressure off to the north and a cold front well offshore.
Thursday night into Friday, a fairly potent shortwave trough
approaches from the Great Lakes. A surface low looks to move
from west to east through Southern New England. Some models have
the system passing far enough to our south to keep us dry,
while others having it getting far enough north to bring
precipitation. With us being on the north side of the surface
low and in the cool airmass, can`t rule out some snow in
Northern Maine if all things work out perfectly...that is, the
system comes far enough north into the cooler airmass with
precipitation intensity peaking around daybreak Friday (minimum
daytime heating). Raised PoPs to chance through the whole area,
but only went with a bit of a mix north of Millinocket early
Friday. Again, still lots of model uncertainty and lots of time
for the forecast to be refined. Most likely solution is little
or no snow. But with leaves still on the trees it bears
watching as any wet snow can lead to impacts on vegetation.
Cool high pressure for the weekend with below average
temperatures. Next precipitation chance late Sunday into Monday.
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR through Monday with light winds. The only caveat
will be KPQI as some fog is possible around daybreak which
could drop conditions briefly to MVFR/IFR.
Tuesday and Tuesday Night...
MVFR likely late Tuesday into Tuesday night with rain and low
Continued breezy with conditions improving to VFR by about mid-
Wednesday Night through Friday...Generally VFR. There is a
chance of a weather system Friday which could bring
precipitation and lower than VFR, but confidence is low.
NEAR TERM: No headlines. N winds to pick up this evening to
10-15 kt w/gusts around 20 kt. Winds are expected to drop by
Monday to around 10 kts. Seas 3-4 ft. Wave runup was a bit high
starting out, so trimmed waves back by around a foot.
SHORT TERM: Small craft likely late Tuesday into Tuesday night
ahead of a cold front. Cold front passes through early
Wednesday, with conditions slowly improving to below small craft
levels around late Wednesday and remaining below small craft
With king tides and a touch of surge and higher seas, can`t
rule out some minor coastal flood and/or wave runup issues
around the Tuesday early afternoon high tide. Most likely looks
to be at the level of a coastal flood statement and nothing
ME...Frost Advisory from 2 AM to 7 AM EDT Monday for MEZ010-011-
Area Forecast Discussion
National Weather Service Grand Forks ND
1008 PM CDT Sun Sep 29 2019
Issued at 1008 PM CDT Sun Sep 29 2019
Update to tweak timing of PoPs/Wx/QPF through Monday afternoon.
Overall, forecast messaging still on track. Latest trends in
environment indicating increasing WAA 925-700MB supporting
continued rain development. Very stable low levels inhibit ML
parcels, however MUCAPE axis of 1000-2000 J/KG on RAP analysis is
show to stretch as far north as Highway 2. This has supported a
few pulsy marginal updrafts, with reports of pea to half inch size
hail. Activity developing over western SD matching CAMs convective
signal and what may organize upstream and move into our CWA late
Elevated instability should continue to increase before
transitioning east Monday morning, and with very high deep layer
shear there is still potential for elevated supercell development
with hail to 2" (higher?) and heavy rain main threats. UH tracks
of latest CAMs trending more towards southeast ND compared to
earlier this evening, which makes sense considering how much
cooler temps are further north and where better instability will
be in place by time activity spreads out of western ND. Tracks
also weaken greatly as they move further east, so there is
uncertainty on whether organized severe threat would hold together
further east in our CWA. Will need to continue to monitor as
environmental parameters could still support isolated sig hail
threat late tonight-Monday morning, with best chance based on
timing after 4AM.
UPDATE Issued at 651 PM CDT Sun Sep 29 2019
Showers and non-severe thunderstorms continue to build and track
over our forecast area with some thunderstorms having history of
0.5" per hour (or more) rates. Luckily training/back building has
been limited, but there is still concern that the potential is
still there and could create localized flood threat. CAMs show
trend towards lull in rain intensity late this evening. Elevated
instability axis builds northward after midnight, and stronger
storms may develop upstream from our CWA and progress eastward
after 4AM. No change in thoughts for late night through midday
Monday severe threat, with signal in CAMs and model environmental
parameters showing potential for elevated supercells. Will
continue to monitor that situation/set up. During this update
minor adjustments were made to reflect near term trends,
otherwise forecast is on track.
.SHORT TERM...(This evening through Monday)
Issued at 317 PM CDT Sun Sep 29 2019
Primary impacts or concerns in the short term involve severe
storms chances and heavy rainfall threat. The rest of today and
into the overnight a warmer and more moist airmass will continue
to lift to the north over the FA. With PWats between 1 and 1.5"
and 850mb jet focusing over the valley will see showers with
embedded thunder persist into the late evening. For the overnight
MUCAPE increases with the 18Z NAM showing 3500j/kg in the
southern valley and cloud layer shear an impressive 50+kts will
see the threat for elevated severe hail storms. CAMs have
indicated stronger UH tracks moving into the FA from the west
after 1am with model soundings showing analogs for significant
hail with values above 2". It is another one of the low
probability occurrence at a specific location with high impact
type of events.
With respect to the widespread rainfall amounts that are expected
across the area overnight into tomorrow the most likely place for
more than 2 inches will be from TVF to southern Grand Forks
county to Valley city areas. Here a narrow strip of 0.75 to 1.25"
has already occurred. Otherwise 1 to 2 inches is still expected
with the higher amounts in the north and also would be if and where
ever an elevated storm tracks overnight. Rainfall move out of the
area during the afternoon with a dry Monday night expected.
.LONG TERM...(Monday night through Sunday)
Issued at 317 PM CDT Sun Sep 29 2019
The extended period starts off with southwest flow aloft and an
upper trough over the intermountain west. A frontal boundary will
extend from New Mexico northeastward through Wisconsin Tuesday
morning...with ND/MN on the cold side of things. The upper trough
will close off early and move eastward through the area as an upper
low on Wednesday night. There could be some light rain showers
across much of the area Wed/Thu, with snow showers possible in the
far north late Wednesday night. With the cooler air in place Tuesday
and the upper low reinforcing temps, highs will stay around 50
degrees for Tue-Thu. Frost will be a concern for growers by mid-late
week as well. However, on Friday the cold surface high moves east
with southerly winds returning ahead of a low pressure system. An
upper trough and surface low then move through the region over the
weekend...with good agreement from the GFS and ECMWF models. There
will be a chance of rain over the weekend with this system.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 651 PM CDT Sun Sep 29 2019
Prevailing MVFR ceilings should decrease to IFR (possibly LIFR)
as low level moisture continues to linger over our area.
Showers/thunderstorm with pockets of light fog are resulting in
vis restrictions varying from 1 to 6sm, but not prevailing for
most terminals in eastern ND and northwest MN. expect lull in
thunderstorm activity late this evening before another round of
storms (possibly stronger) develops after 9Z through 15Z. Showers
may linger into the day Monday with ceilings slowly increasing.
Some locations (KFAR has best chance) may see VFR by the end of
the TAF period Monday afternoon.
Winds will remain easterly tonight, though strongest gusts will
decrease this evening. Low level wind shear will be possible for
MN terminals late tonight and Monday morning. Eventually winds
should shift to the north and then northwest as the larger system
moves across the region.
Area Forecast Discussion
National Weather Service Grand Rapids MI
1006 PM EDT Sun Sep 29 2019
Issued at 304 PM EDT Sun Sep 29 2019
- Rain tapering off late this afternoon
- Much warmer for Monday and Tuesday
- Heavy rain possible for the middle part of the week
Issued at 1007 PM EDT Sun Sep 29 2019
I updated the forecast to have drizzle and areas of fog overnight.
I do not think the fog will get to thick but the warm front starts
to make a serious push north overnight. It is after say 3 am that
the low level jet (the main core of the 40 to 50 knot winds) which
now is mostly west of the Mississippi River but after 3 am a
branch of it focus on Western Wisconsin. That push of the warm
front will bring more moist air into the cooler air over us and
that typically means fog.
Another aspect is there is a shortwave (convective) passing over
over the souther 1/3 of Southern Lower Michigan. There are some
scattered showers with that. Not enough instability for
thunderstorms. So prior to 3 am I see areas of fog and drizzle
with a few showers mostly south of I-96.
After 3 am through the southern branch of the polar jet reaches
southwest Michigan with the exit region over our western CWA. This
allows the more unstable air to move in with that so the push of
the warm front may cause scattered thunderstorms to develop. I
admit the MUC is marginal only around 500 j/kg but the SPC 3 hour
probability of thunderstorms does suggest thunderstorms west of
US-131 in the 3 am to 10 am time frame. Also surface convergence
on the warm front will help that cause too. If they even happen
(they have been forecast by the HRRR and ESRL HRRR for most of the
model runs I have seen tonight)they should not be anything to
special, still it looks reasonable enough to have in the
I still believe the warm front should clear the CWA by late
afternoon so we should see highs well into the 80s by late
afternoon. The air should be to stable for convection then but
curiously the RAP model shows MUC near 3000 j/kg over western
Lower Michigan by mid afternoon. There is not focus for storms to
develop so this should be no problem unless the warm front does
not get through.
The bottom line is we will see fog and patchy drizzle most of the
night with temperature mostly in the 50s. Clouds should clear by
noon or so, then temperatures should jump into the 80s.
.DISCUSSION...(This evening through next Sunday)
Issued at 304 PM EDT Sun Sep 29 2019
This initial round of rain today will push east of the CWA over
the next couple of hours as the mid level wave responsible for
this event pulls away. Rainfall amounts of up to 1.7 inches have
been observed just from todays rain with the highest amounts along
and south of I96. Clearly the ground is saturated in many areas as
a result of all the recent rain.
Scattered showers and storms are still possible tonight into early
Monday. This is when the warm front will be lifting through.
Locally heavy rain looks to be the main risk with any storms.
While a wing of instability will lift northward through the CWA
the main low level jet is off to the west.
Deep warm air advection sets up for Monday into Tuesday. A low
level jet is shown to track through Wisconsin into Northern Lower
Michigan. Thus it appears the main storm activity will be focused
in those areas. This leaves my northern zones most prone to
impacts. We will feature the highest POPs for those locations.
Right now if we do see storms then the main risk would be for
gusty winds and locally heavy rainfall.
The main period of concern is Tuesday night into Thursday and
flooding appears to be the main potential impact. The period will
feature a very moist airmass with several rounds of showers and
storms likely to occur. With the ground saturated from all the
recent rain and rivers on the rise the region will be prone to
flooding. The surface frontal zone slips slowly southward through
the region during this period and it could stall out for a period
of time. Meanwhile a mid level wave is shown to arrive Wednesday
night into Thursday. It does still look like we will be on the
cool side of this system. This will act to keep the storms
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 748 PM EDT Sun Sep 29 2019
For the most part the rain has come to an end early this evening,
through drizzle is very much possible into the mid evening at all
TAF sites. Solid IFR cigs prevailed from I-96 to I-94 and until
the warm front clears the area during the midday hours of Monday,
I expect IFR cigs to prevail.
There are two glitches to watch for. The first is dense fog. We do
have currently have a stationary front south of Michigan, but it
will turn into a warm front after midnight and march it`s way
north into Southwest Michigan during the early to mid morning
hours of Monday. Once the front really starts to push north the
higher dew point air will have to mix with the cooler air
currently over this area. Typically that means fog. The RAP and
NAM models are forecasting dense for near I-94 toward morning.
The other glitch is thunderstorms developing on the warm front as
it starts to lift north. Both the HRRR and ESL HRRR shows this
happening. The storms would develop southwest of AZO and march
northeast into the I-96 TAF sites by 12z before the storms
Issued at 304 PM EDT Sun Sep 29 2019
Gusty east winds will continue this evening with some values over
20 knots at times. As a warm front lifts northward through the
zones the wind will shift and become southwesterly Monday into
Monday night. Northern zones will need to be monitored for
possible headlines mainly starting Monday night. Confidence is not
high enough yet to go with one.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
853 PM PDT Sun Sep 29 2019
.SYNOPSIS...Isolated light showers are possible overnight. Dry
weather will return to all areas on Monday, but temperatures will
remain cool. A warming and drying trend is then forecast for
Tuesday and Wednesday. A dry weather system passing across
northern California on Thursday will result in a pause in the
warming trend. But warming will then likely continue late in the
week and into next weekend.
.DISCUSSION...As of 8:50 PM PDT Sunday...A deep upper trough over
the Western U.S. maintained cool temperatures across our region
today. Afternoon highs were anywhere from 4 to 12 degrees cooler
than normal. An shortwave embedded in the northerly flow on the
back side of the longwave trough dropped south into northern
California today, triggering thunderstorms as far south Mendocino
County late this afternoon. Scattered light showers managed to
develop as far south as Sonoma and Napa Counties by early this
evening and measurable rain has been recorded in northern and
western Sonoma County. Recent radar data indicate shower activity
has been dissipating across the North Bay over the past hour,
which is consistent with model forecasts. The 00Z NAM forecasts no
additional measurable rainfall overnight, while the latest HRRR
continues to show isolated light showers through late tonight.
Current forecast maintains slight shower chances overnight, but
the potential for thunderstorms has ended.
The airmass over our area remains very cool, with the 00Z Oakland
Sounding indicating an 850 mb temperature of less than 5 deg C.
Temperatures will remain well below normal on into Monday as the
upper trough remains slow to move off to the east. One final
shortwave is forecast to drop in from the north on Monday morning,
but all precipitation with that disturbance is expected to remain
to our north and east.
The upper trough is forecast to finally move off to our east by
Tuesday, allowing a warming and drying trend to start that day,
and continue on into Wednesday. Models then generally agree that
the warming trend will halt temporarily, or even reverse slightly,
on Thursday as an upper trough moves across northern California.
Precipitation with the Thursday trough is forecast to remain well
to our north. The warming trend will then likely redevelop on
Friday and continue on into next weekend as an upper ridge
develops near the West Coast.
.AVIATION...as of 04:55 PM PDT Sunday...Breezy onshore winds with
occasional gusts will continue into the early evening and decrease
after 03-04z. Overnight, a weak system will move through the
region from the north, producing mainly FEW/SCT clouds with bases
2000-4000 feet. FEW clouds with bases around 1500 feet will also
occur. MVFR cigs most likely to develop around the Monterey Bay
terminals overnight as moist northwest winds interact with the
terrain. Elsewhere, VFR should prevail through the period. A few
brief, isolated light showers are possible overnight tonight but
too low of confidence and isolated to include in the TAFs.
Vicinity of KSFO...VFR. West winds with gusts 20 to 25 kt will
diminish 03-04z this evening. FEW/SCT clouds with bases near 4000
feet will continue through the overnight hours. A few clouds near
1500 feet may also develop overnight.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...West-northwest winds 10-15 kt will
continue through early evening and decrease overnight. MVFR
developing overnight with SCT/BKN clouds near 2000 feet. These
cigs will persist into Monday morning before clearing. Isolated
showers may also be possible early Monday morning. Will include in
the TAFs if confidence increases.
.MARINE...As of 8:43 PM PDT Sunday...Scattered showers will
continue overnight across the coastal waters. Lighter winds are
expected overnight through early Monday as an area of low pressure
over the Great Basin moves east. Northwest winds will increase on
Monday afternoon, resulting in hazardous conditions for small
crafts Monday afternoon through evening. Breezy to gusty northwest
winds will continue through the middle of the week. A moderate
northwest swell and long period southerly swell will continue
through mid week.
.Tngt...SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 9 PM
PUBLIC FORECAST: Dykema
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AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
1000 PM EDT Sun Sep 29 2019
A backdoor cold front will cross the Mid-Atlantic Monday and Monday
night with surface high pressure building into the region beginning
Tuesday. High pressure will then translate offshore, but extend
inland across NC through the middle of the work week.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 1000 PM Sunday...
Upper air analysis shows the anomalous 850mb ridge (1606m) centered
overhead tonight and a the 700mb ridge (3124m) centered between GSO
and FFC. A surface cold front, mmodulated in places by outflows,
stretched from the Delmarva to the Shenandoah`s to the IL/IN/KY
border region. Some convection associated with a weak upper
disturbance rounding the ridge and its weak surface trough, as well
as storms rolling off the mountains has mostly died off since
sunset, though one cluster showers and isolated storms on outflow
nearing the NC/VA border appears to be deep enough to tap into
lingering, slightly elevated instability noted on the SPC
mesoanalysis. Have adjusted POPs to account for some what should be
a diminishing trend in the northern Piedmont in the next few hours.
The other forecast challenge overnight is cloud cover associated
with the northeasterly flow behind the cold front as it pushes south
with otherwise little fanfare. Most guidance suggests some
stratus...already observed around the Tidewater...will spread
southwest across the area overnight, but recent satellite trends and
latest RAP soundings have me wondering how deep the moist layer
(near 1000ft) will be. Still increasingly cloudy skies and lows in
the upper 60s to lower 70s.
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
As of 400 PM Sunday...
Monday morning widespread stratus will be in place across
central North Carolina in the wake of a weak cold front. Global
and high res models are indicating some weak WAA/isentropic
upglide rain across the Triad Monday morning, but this signal is
weak. Forecast soundings show minimal saturation with little in
the way of warm rain process taking place (collision and
coalescence). Therefore anything that does occur will likely be
drizzle or light rain. By Monday afternoon breaks will start to
slowly appear in the clouds with a slow warming. Highs for
Monday will be extremely difficult as widespread precipitation
to help reinforce the CAD will be non-existent. The NAM guidance
has upper 70s for the Triad, while the ECMWF is indicating
mid-80s. For now have kept the forecast trended towards the
warmer guidance as reinforcement of the CAD will be difficult
given the lack of precipitation. Any breaks in the clouds will
also likely result in surface temperatures quickly rising as 850
mb temperatures are forecast to be around 15 degrees C.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 233 PM Sunday...
Ridging both sfc and aloft will keep a dry and unseasonably warm
pattern across our area for the mid-week period, until a strong cold
front moves through on Friday. That front will bring a chance for
scattered afternoon and evening showers and t-storms on Friday,
highest PoPs across the east invof more abundant moisture.
High pressure will then build into the area from the north for this
upcoming weekend, bringing with it a dry and much cooler airmass
that will result in temps closer to normal, if not several degrees
below normal. In short, very nice and comfortable weather is in
store for central NC for next week.
.AVIATION /00Z MONDAY THROUGH SATURDAY/...
As of 725 PM Sunday...
24 hour TAF period: Some scattered showers and thunderstorms will
continue through this evening, though coverage is not high enough to
include at a specific terminal. Best chances of showers/storms will
be at KINT and KGSO this evening. Expect low stratus to develop and
spread across central NC tonight, earliest at KRWI and KRDU and
latest at KINT and KFAY. Cigs should initially be around 1 kft,
briefly dipping into IFR before daybreak. Models suggest stratus
will be slow to scatter and lift on Monday, potentially remaining
MVFR into the late morning/early afternoon (though confidence in the
timing is low). Winds should be light and variable tonight (though
generally out of the east), increasing into the 5-10 kt range during
the day Monday. -KC
Looking ahead: VFR conditions are expected to prevail through the
extended period, though there could be a period of stratus around
3000 ft Monday night/Tuesday morning. -Haines
Record High Temperatures (Year)
GSO RDU FAY
9/29 90 (1921) 92 (1941) 95 (1933)
10/2 91 (1986) 91 (1986) 93 (1986)
10/3 91 (1986) 91 (2002) 95 (1986)
Record High Min Temperatures (Year)
GSO RDU FAY
9/29 71 (2015) 74 (2015) 75 (2015)
Area Forecast Discussion
National Weather Service Riverton WY
236 PM MDT Sun Sep 29 2019
.SHORT TERM...This evening through Monday
Continued areas of precip moving north-northeast across the forecast
area as of 20Z this afternoon. Will continue with the winter weather
advisory for the northwest mountains, which will run to 00Z this
evening. Will also continue with the high wind warnings for eastern
Sweetwater and into Natrona counties until 01Z this evening based
upon recent reports of winds approaching 50 mph into the high wind
warning area. The latest 20Z HRRR model update indicates that the
scattered precip should slowly lessen with time into the evening,
and expect that most of the precip should be confined to northwest
Wyoming by after 03Z tonight.
Most of the lingering precip into northwest and west of the
Continental Divide should end as a period of light snow/flurries
before ending generally by 06Z tonight. Much colder air will be in
the wake of the northeast movement of the vort max at 500 millibars
and surface cold front moving through the area after 06Z tonight. It
is expected that widespread temperatures should drop well below
freezing into the mid-upper teens and into the low-mid 20s
especially west of the Continental Divide. Have issued a freeze
warning for the western valleys and basins from 03Z tonight until
The short term models differ involving timing of the next short wave
to push across northwest Wyoming on Monday. The ECMWF model is
quicker involving the increased low level moisture into the forecast
area, compared to the slower GFS model solution. Will continue with
isolated/scattered snow showers west of the Continental Divide
through early afternoon, and then will follow closer to the GFS
timing involving more numerous snow showers expected to move into
northwest Wyoming by around 21Z Monday. Generally lighter precip
amounts are expected, so will not be opting for a winter weather
advisory at this time for Monday. May need to trend closer to the
colder NAM temp guidance for Monday afternoon high temps.
.LONG TERM...Monday night through Sunday
Some lingering showers in the northwest and north are possible
Monday night through Wednesday as the Canadian Low moves across
northern Montana but most locations will be drying out. With
moderate ridging building a warming trend will occur through the
end of the work week with temperatures rising to near normal. The
next system bringing precipitation will approach the region by
next weekend, but models are not yet in agreement with timing and
coverage. The ECMWF is still indicating Friday afternoon could see
scattered showers across the northern half of the area while the
GFS is dry. Have kept precip chances more in line with the ECMWF
for now. Gusty afternoon winds will likely return next weekend
across southern Wyoming.
.AVIATION...For the 00Z TAFS through 00Z Monday
Rain and snow will decrease after 00Z with VFR to MVFR conditions
occurring at times. Mountains will be frequently obscured. Isolated
rain and snow showers will occur after 01Z.
Along and east of the continental divide, VFR to MVFR conditions
will occur through 02Z with local IFR conditions in areas of heavier
precipitation. The showers and storms will decrease after 02Z with
only isolated activity through 06Z. Mountains will be frequently
Strong to high southwest winds will occur from KRKS to KCPR this
afternoon until shortly after sunset.
A cold front will continue its east-southeast movement through the
region tonight and into Monday. Lingering rain and snow showers
across the area will slowly dissipate by late tonight. Breezy to
windy conditions will continue until mid evening, with high winds
expected to continue into early evening in portions of Sweetwater
and Natrona counties. Isolated snow showers in western sections on
Monday will become more numerous by late afternoon across west and
into northwest Wyoming as another weaker system moves across the
area through Monday night. Relative humidity values will remain
above critical values through the short term period. Mixing and
smoke dispersion will remain in the poor category in the northern
basins to excellent range in the eastern and southern sections.
Winter Weather Advisory until 6 PM MDT this evening for WYZ001-
Freeze Warning from 9 PM this evening to 10 AM MDT Monday for
High Wind Warning until 7 PM MDT this evening for WYZ020-030.