Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/21/24
Area Forecast Discussion
National Weather Service Boise ID
850 PM MDT Tue Aug 20 2024
.DISCUSSION...The clouds should clear later this evening as the
upper- level jet max moves northeast. A few showers and
thunderstorms have formed northwest of Baker County, just ahead
of the upper- level low over Central Washington. Current radar
trends, along with the latest High-Res models, suggest this
activity will remain north of Baker County.
Fires in the Central Mountains continue to be quite active
despite the cloud cover. Smoke is expected to get trapped in the
valleys again tonight, with smoke filtering into the Western
Snake River Plain by Wednesday morning. The latest HRRR model
indicates that the Lower Treasure Valley and Upper Weiser Basin
will likely experience the most smoke. However, there is a 20%
chance that east Boise and the foothills could see smoke
Wednesday morning. No updates are needed at this time.
&&
.AVIATION...VFR, except localized MVFR/IFR and mountain
obscuration in the Central ID Mountains due to wildfire smoke,
especially near KMYL. Isolated thunderstorms and showers in far
northeast Valley County tomorrow afternoon. Surface winds: N-NW
5-15kt becoming variable early tomorrow morning everywhere
except in the KBKE-KONO then back to W-NW 10-15 kt with gusts to
25 kt. Winds aloft at 10kft MSL: S-SW 15-30 kt.
KBOI...VFR. Slight chance (20% chance) for 5SM-6SM visibilities in
smoke Wednesday morning, but higher chance (60%) by Wednesday
evening. Surface winds: NW 5-8 kt becoming variable after 21/03Z
then breezy W-NW 8-12 kt with gusts to 25 kt by the evening.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday night...Latest models
continue to show 15-25 percent coverage of showers and
thunderstorms in western and northern Baker County/OR this
evening, then a 15-25 percent chance of showers and thunder-
storms again in eastern Valley County/ID Wednesday afternoon,
as a weak upper trough passes by to the north. The rest of our
CWA will stay dry with partly to mostly cloudy skies in the
north to mostly clear skies in the south. Temperatures will be
cooler tonight through Wednesday night with lows in the 40s in
the mountains and 50s to lower 60s in the valleys, with highs
Wednesday in the mid 70s to mid 80s in the mountains and 80s in
the valleys. Thursday will be sunny and hotter under southerly
flow aloft ahead of a cooling upper low approaching from the
northwest coast. The low will move inland across Oregon Friday
and western Idaho Friday night and Saturday with showers and
thunderstorms and bringing much cooler air to the region, the
coolest since June. Latest models are a little slower than
before, with the first chance of showers and thunderstorms
reaching Harney County/OR Friday morning, increasing to a 30-40
percent chance Friday afternoon, then similar chances spreading
into western Idaho Friday night and a 30-50 percent chance
everywhere Saturday. A Pacific cold front Friday will lower high
temps to the 60s and 70s Friday and Saturday with lows temps in
the 40s and 50s. Pre-frontal southwest winds Friday will
increase to 15 to 25 mph in southeast Oregon and in the southern
Idaho Highlands. HRRR model keeps near-surface smoke in and
east of the active fires in the Boise National Forest.
LONG TERM...Friday through Tuesday...The cool upper low will
exit east Sunday and begin a warming and drying trend with
temps rising to normal by Tuesday and above normal Wednesday,
then holding level. The Canadian model has dropped its cooling
upper low for late next week and now is in line with the other
warmer long term models and ensembles.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Fire Weather Watch from Thursday afternoon through Thursday
evening IDZ403-421.
OR...None.
&&
$$
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DISCUSSION...JDS
AVIATION.....SA
SHORT TERM...LC
LONG TERM....LC
Area Forecast Discussion
National Weather Service State College PA
1049 PM EDT Tue Aug 20 2024
.SYNOPSIS...
A deep upper level low will drift slowly to the
south from Quebec Canada. This weather feature will be
responsible for stretch of cooler temperatures and fall-like
weather through the end of the week. Rain-free weather continues
into this weekend with warmer and more humid conditions.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A taste of fall out there with dewpoints in the 40s to lower 50s
and temperatures already ranging from the upper 40s north to
around 60 in the southeas. Sprinkles are coming to an end across
the north, and the balance of the overnight will be mainly clear
(central and south) to partly cloudy north.
The deep upper level low near Montreal Canada will drift slowly
to the south into northern NY over the next 36 hours, resulting
in the coolest stretch of weather we have seen since this past
Spring. We continue to lean slightly cooler than NBM guidance
and are maintaining patchy late night valley fog over the
northern valleys. Mins could dip as low as 38-39F in some of
the protected high valleys across the North, while lows
elsewhere early Wed will be mainly in the lower 40s over the
Northern and Western Mtns, and mid to upper 40s throughout most
other locations of Central and Southern PA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
The aforementioned upper low is progged to make its closest
pass to PA Wednesday, resulting in another cool/breezy day with
steeper lapse rates bringing a better chance of diurnally-
driven showers, especially over the northeast quadrant of the
forecast area. Ensemble prob of CAPE GRTN 500 J/KG is non-
existent over the CWA so the Prob Thunder Grids will show less
than 5 percent probs for Wed afternoon.
Forecast soundings indicate early sunshine should give way to a
mix of sun and cumulus. Deeper vertical mixing than (Tuesday)
and up to around 8 KFT AGL will create a moderately gusty, NW
sfc wind once again - up to 25 mph at times during the late
morning and afternoon hours.
Dry air and light winds associated with surface ridging should
result in a very cool Wednesday night by August standards. Have
undercut NBM min temps slightly based on the expectation of
efficient radiational cooling. The upper low is progged to begin
lifting out by Thursday, resulting in fair weather and less
diurnal cumulus. Despite mostly sunny skies, lingering chill
aloft should result in max temps still 5-10 degrees below
average.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Strong upper trough will continue to dominate New England and
the Mid Atlantic this week while starting to lift slowly
northeastward this weekend as ridging builds from the Central
US.
Dry weather, more sun than clouds, and comfortable humidity will
continue through the extended period. Fog becomes more likely
each morning beginning on Thursday with high pressure at the
surface. By the weekend, humidity and temperatures trend upward
with southerly return flow behind retreating high pressure. We
could see a shower or two by the end of the weekend, but dry
weather looks like a sure bet for most of the extended period.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are expected through 00Z Thursday with moderate-
to-high (60-70%) confidence. A broken-to-overcast cloud deck
around 5000-7000 AGL will continue to erode this evening with
clear-to-scattered conditions expected throughout the overnight
period. A slight breeze is expected to continue at all
airfields, keeping fog concerns to a minimum except at BFD where
winds going calm in the ~09Z-11Z timeframe does provide some
forecast complications. Based on RAP model soundings, it does
look like low-level moisture will be lacking in this timeframe,
but have kept mentions of VCFG in this TAF cycle as there is
still some potential for fog and/or low ceilings forming along
BFD in the ~10-12Z Wednesday timeframe.
After sunrise, a broken-to-overcast cloud deck is expected to
continue moving generally north-to-south across all of central
Pennsylvania. Based on a combination of HREF/RAP/GLAMP guidance,
generally expect these ceilings to be ~4000-6000 AGL although
some lower cloud decks could bounce some observations at BFD/JST
closer to MVFR thresholds. At this time, low (< 30%) confidence
in any MVFR ceilings, so have kept the 00Z TAFs with prevailing
VFR conditions at all airfields through 00Z Thursday. There
will also be a slight chance of an isolated SHRA at BFD/IPT
mainly in the ~15-22Z Wednesday timeframe; however, lower
confidence in coverage keeps mentions out of the TAF this cycle.
Outlook...
Thu...VFR/No sig wx
Fri-Sun...Mainly VFR. Isolated PM SHRA/TSRA possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/DeVoir
NEAR TERM...Lambert/DeVoir
SHORT TERM...Lambert/DeVoir/Fitzgerald
LONG TERM...DeVoir/Banghoff/Gartner
AVIATION...NPB
Area Forecast Discussion
National Weather Service Dodge City KS
500 PM CDT Tue Aug 20 2024
...Updated Aviation...
.KEY MESSAGES...
- Little change to the sensible weather today, with afternoon
highs again in the mid 80s to mid 90s.
- Scattered thunderstorms, some of which may be marginally
severe, are possible across the north/northwest zones tomorrow
evening.
- Mostly dry, warming trend continues into the weekend, with
widespread triple digit highs likely.
&&
.DISCUSSION...
Issued at 200 PM CDT Tue Aug 20 2024
19Z water vapor satellite imagery and RAP upper air analysis
indicates a strong, cut-off mid-level ridge remains in place
over the southern and central plains, flanked by a pair of
troughs on either side. At the surface, temperatures have once
again struggled to warm appreciably through the morning and
early afternoon across much of the area under another stubborn
stratus deck, but visible satellite trends suggest this cloud
cover will soon erode away allowing full sunshine to support
afternoon highs ranging from the mid 80s northeast to the mid
90s near the OK and CO borders. Later tonight, thunderstorm
development over the Rockies in southern CO will spread eastward
towards our area, but confidence is very low this activity will
actually cross into our area as HREF probability of QPF > 0.01"
is 20% or less for all zones. That said, if a stray storm
manages to reach far southwest KS, a brief marginally severe
wind gust cannot be ruled out.
Daytime Wednesday, short range ensembles agree the mid-level
ridge will begin to inch eastward ever so slightly. Strong
subsidence under this feature will support 850-mb temperatures
rising by 2-3C, which will translate into a slightly warmer day
for southwest KS as afternoon highs reach the upper 80s
northeast to the upper 90s southwest. Wednesday afternoon and
evening, a weak vorticity max is expected to eject out of the
central Rockies and into the central plains, resulting in
scattered showers and thunderstorms shifting into our area after
9pm CDT. While proximity to the center of the mid-level ridge
will only foster weak deep-layer shear, steep lapse rates may
still support a marginal severe threat with damaging wind gusts
and quarter-size hail the primary threats.
Thursday through the end of the period, medium range ensembles
agree the mid-level pattern will remain relatively static, with
the ridge continuing to inch east/northeastward while
expanding. This will engender a mostly dry, warming trend across
the central plains with afternoon highs warming into the 100-105
range by the weekend. The only hope for any precipitation
chances for our area exists Thursday evening/night and favor the
northern zones where weak mid-level perturbations may traverse.
However, LREF probability of QPF > 0.01" is only in the 10-20%
range, so confidence remains very low.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 500 PM CDT Tue Aug 20 2024
Excellent flying weather will continue through this TAF period,
with VFR/SKC and scattered cirrus at times. Scattered
stratocumulus currently will dissipate by sunset. Light
southeast winds will prevail at 9-12 kts. After 15z Wed, SE
winds will increase modestly at all airports, gusting 23-25 kts.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Springer
AVIATION...Turner
Area Forecast Discussion
National Weather Service Des Moines IA
622 PM CDT Tue Aug 20 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Light rain showers mainly west rest of today into Wednesday
- Mainly dry through the rest of the week, though a few on and off
showers and weak storms possible into Friday north and west
- Gradually warming temperatures, especially this weekend into the
90s
&&
.DISCUSSION...
Issued at 236 PM CDT Tue Aug 20 2024
Fairly quiet weather over the region today, with surface analysis
showing a large area of high pressure sitting over the Upper
Peninsula of Michigan, leaving Iowa in surface southeasterly flow,
while further west, a weak area of low pressure remains. Light rain
overall has been seen mainly over eastern South Dakota and Nebraska
into western Iowa, though drier air over Iowa has been limiting much
of this rain to reach the surface, with little accumulations so far.
Looking further into model soundings, the lower level dry air
generally looks to keep conditions dry for most, though some
guidance indicates better moisture return later this evening and
into Wednesday morning that may allow for at least a better chance
for rain showers mainly over western Iowa. CAMS continue to be more
robust with better moisture availability and overall coverage across
the state, but given that this has not been the case so far,
confidence remains on the lower end to increase PoPs very much
across the state. Regardless, little impact if any for the rest of
the day into Wednesday, with overall totals looking to remain on the
lower end as ensemble guidance keeps values generally less than a
quarter inch, though slightly higher values further northwest are
not out of the question. Otherwise, cloud cover is expected across
Iowa for the rest of the day, with temperatures increasing a bit
more yet with highs expected in the mid to upper 70s. Lingering
smoke per HRRR guidance is expected to remain overhead at least into
Wednesday as well, though this may not be visually as noticeable
given the increased clouds.
As upper level ridging continues to drive the larger scale weather
pattern, a few shortwaves riding this ridge looks to bring at least
some potential for showers and maybe a few storms again by Friday
morning as low level WAA and moisture transport increases mainly
over the western portion of the central into northern plains.
Looking at overall forcing, the overall placement keeps more
favorable conditions mainly north into Minnesota Thursday and Friday
as the boundary associated with this wave moves through, as depicted
per guidance. For Iowa, could see a potential for a few on and off
showers and storms, though looking rather weak given limited shear
and instability into Friday, mainly over portions of western into
northern Iowa. Otherwise expecting largely dry conditions for most
through the rest of the work week, with high temperatures reaching
into the upper 70s to low 80s with south-southeasterly flow turning
slightly breezy each day with increased mixing due to diurnal
influences.
Into the weekend, the thermal ridge will continue to move eastward
into the Central US, which will come with much warmer temperatures
than have been experienced as of lately, with values soaring through
the 90s into early next week. Long-range models continue to
show additional low-end chances for showers and possibly some
storms during this time as well, but given differences in timing
and coverage, this potential is more uncertain and will be
better known in the coming days.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 622 PM CDT Tue Aug 20 2024
This TAF cycle continues to maintain VFR conditions through the
period. Scattered light showers are moving over northwest into
north central Iowa early this evening with several sites
reporting -RA. However, VFR conditions have remained so these
showers are quite light. Confidence is high enough to add in -RA
at FOD given the incoming showers that will prevail for the
next few hours intermittently. MCW may also need an amendment,
but more dry air over central Iowa leads to lower confidence in
adding in -RA.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Bury
AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Peachtree City GA
753 PM EDT Tue Aug 20 2024
...New 00Z Aviation Discussion...
.SHORT TERM...
(This afternoon through Wednesday)
Issued at 255 PM EDT Tue Aug 20 2024
Very few impacts in the short term forecast for the rest of today
and tomorrow. Afternoon cumulus have built across the 85 corridor
and points south and will stick around through sunset. The big
weather story may be the lows tonight, where areas in north Georgia
will drop into the 50s (!) with widespread 60s across the rest of
the CWA, with the exception of far south central Georgia where
better moisture continues to hang on.
Going into tonight and tomorrow, a backdoor front will slide through
the area bringing winds back out of the east. A by-product of this
may be that we see some moisture return from the Atlantic across the
area. This may be enough to kick up a few showers and
thunderstorms in the afternoon across central Georgia. The HRRR is
a bit of an outlier, firing off some storms across the metro
around sunset. Not fully willing to buy into a solution like this
given dry air remains aloft and storms may struggle with
entrainment, but worth noting the uncertainty here. Lows tomorrow
night will again be in the 60s.
Lusk
&&
.LONG TERM...
(Thursday morning through next Monday)
Issued at 255 PM EDT Tue Aug 20 2024
By Thursday into Friday the troughing that was just to our east will
have moved further to the east whereas the surface high pressure
will become dampened due to the low pressure going into the pacific
NW. This will ultimately take us away from the influence of the more
synoptically driven dry air and begin to bring moisture into the
southern portion of the area as we sit in this area. The moisture is
on the increase through the enc of the forecast period into early
next week. With this I have kept with the previous forecast of ~30%
PoPs for the southeastern part of the CWA. With this showers and
thunderstorms can be expected for that area. We are looking at temps
rising into the mid to upper 90s again towards the later half of the
period.
Hernandez
&&
.AVIATION...
(00Z TAFS)
Issued at 743 PM EDT Tue Aug 20 2024
VFR conditions throughout TAF cycle. NW winds will turn to the NE
after 05-06Z and will gradually become E by the end of the TAF
period. Wind speeds around 10-12KT this evening will diminish to
5KT or less overnight before picking back up to 5 to 8KT
after sunrise. Cu field will develop across northern TAF
locations tomorrow after 15Z and MCN/CSG after 17Z.
//ATL Confidence...00Z Update...
High confidence on all elements.
KAB
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 66 85 64 85 / 0 10 20 20
Atlanta 66 87 67 85 / 0 10 20 20
Blairsville 57 79 59 79 / 0 10 10 30
Cartersville 61 87 66 86 / 0 10 10 20
Columbus 69 91 71 89 / 0 20 20 30
Gainesville 65 84 65 84 / 0 0 20 20
Macon 68 89 67 87 / 0 20 20 20
Rome 60 86 65 85 / 0 0 10 20
Peachtree City 65 87 66 85 / 0 10 20 20
Vidalia 71 89 68 86 / 0 20 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Lusk
LONG TERM....Hernandez
AVIATION...KAB
Area Forecast Discussion
National Weather Service Grand Junction CO
521 PM MDT Tue Aug 20 2024
.KEY MESSAGES...
- Moisture returns tonight into tomorrow and lingers through
the end of the week. Once again, widespread showers and
thunderstorms will be possible. Main concerns will be gusty
winds, hail, and heavy rain. Localized flash flooding will be
a concern.
- Cooler temperatures take hold for the latter part of the week
with more cloud cover and precipitation anticipated.
- Dry conditions look to return next week.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 232 PM MDT Tue Aug 20 2024
This morning`s sounding at GJT saw PWATs fall from 1.12" yesterday
evening to 0.88" showing that drier air has indeed arrived. This
will work to limit convective coverage this afternoon and evening
with higher-terrain areas experiencing the highest chances for
showers and storms. With drier air in place, gusty outflow winds
will be the primary threat posed by precipitation today.
The main focus in the short term forecast is the return of monsoonal
moisture advection tonight into tomorrow. This happens as the
surface high that`s currently located over New Mexico slowly noses
eastward towards the Texas Panhandle. As southwesterly flow picks up
overnight, isolated showers may form on the moisture gradient as it
slides to the northeast. The most recent run of the HRRR is keen for
some overnight development, while other hi-res models like the NAM
NEST are drier or slower to tap into the moisture feed. Regardless,
afternoon convection is likely tomorrow afternoon with showers and
storms initiating over the high terrain. Localized heavy rainfall,
gusty outflow winds, and small hail will be the main threats of any
stronger storms that form tomorrow.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 232 PM MDT Tue Aug 20 2024
On Thursday, we will be under southwest flow aloft thanks to a low
pressure off the coast of WA/OR and high pressure over TX. This flow
will be tapped into modest monsoon moisture and advection will have
already brought that moisture here by mid day. PWAT values will be
170 to 200 percent of normal with 700 mb mixing ratios 7-10 g/kg,
which is fairly high. Chances are moderate that there will be either
cloud cover and or precipitation during the morning hours. With the
moisture in place the potential for heavy rain increases, which will
only be realized if instability can build. Therefore the heavy rain
threat will depend a lot on the morning cloud cover. Places that
clear out in the morning will have the higher chances, but still
nonzero for other locations that may stay cloudy. As of now the
models are showing a strong QPF signal across the southern half of
the forecast area for Thursday afternoon. The potential for flash
flooding will be highest along steep terrain, near burn scars, as
well as slot canyons and slick rock areas. It appears that
convection could linger into the overnight hours. Regardless it
appears to be a fairly active day.
On Friday, the low pressure makes landfall and pushes inland across
the Pacific Northwest. This will cause the pressure gradient to
increase overhead. The moisture values are fairly similar as it
appears advection will persist. The models are showing QPF in the
morning, which again plays a role in where instability is able to
build. Any storms that form on Friday should be capable of heavy
rainfall. The one difference is an increase in flow may limit the
flash flood potential. Although any storm training could lead to
heavy rainfall. Saturday is a transition day as the trough begins to
swing over the northern Great Basin and Pacific Northwest. Afternoon
convection is still expected and there may even be some forcing. The
difference this time is that the moisture is on the decrease and
flow increases once again. This could change the dynamics therefore
affecting the convection overall. The synoptic dry slot comes over
on Sunday, so we should see a downtick in storms in general. It
could be dry for most locations. Winds are gusty this weekend with
the trough passage. On Saturday night the trough may cool temps
enough for snow on the highest peaks. Amounts appear to be minor
attm.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 518 PM MDT Tue Aug 20 2024
Isolated to widely scattered showers and thunderstorms continue
to move through the area at this hour, bringing frequent
lightning, gusty and erratic winds, some small hail and brief
heavy rain. At the moment, KHDN and KTEX are the most likely to
see any impacts from this activity. Otherwise, look for showers
and storms to taper off over the next 3-6 hours, with gradually
clearing skies and terrain driven winds. Tomorrow is expected to
be something of a repeat of today, but with increasing coverage.
VFR conditions are expected to prevail for the next 24 hours.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...KAA
LONG TERM...KJS
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Gray ME
943 PM EDT Tue Aug 20 2024
.SYNOPSIS...
An upper low drops south into Upstate NY this evening. This
upper low will slowly meander across northern New England
through Thursday bringing chances of showers, and maybe a
thunderstorm, mainly in the afternoons and across the north. The
upper low exits Friday with high pressure building in for the
weekend. This will start a warming trend, with temperatures
climbing slightly above normal.
&&
.NEAR TERM /THROUGH TONIGHT/...
Update PM...
Clouds continue to dominate the region for central and northern
portions of the forecast area. Some breaks continue to gradually
form over southern areas, especially southern New Hampshire.
Otherwise, beside keeping cloud cover over northern sections,
there will be just some minor tweaks otherwise to the near term
portion of the forecast this evening. It will be a chilly night
with some 40s in the north.
Prev Disc... Plenty of low level moisture continues across the
region, however with some breaks in the cloud cover over
southern portions of the forecast area. Latest radar imagery
continues to show some precipitation in the mountains and
foothills where we have scattered showers with some drizzle in
the forecast for the overnight hours. This is in good agreement
with the latest HRRR solution.
It will be one of the more chilly nights that we have had for
quite some time. With the decreasing cloudiness, temperatures
will be allowed to fall rather quickly overnight with min
temperatures reaching the upper 40s in the north to the 50s
elsewhere.
Prev Disc...
Overcast skies remain bottled up NW of the mountains this
evening and overnight. Meanwhile, remainder of the CWA will
likely see some thinning as the night goes on. Plenty of
moisture remains in the low levels, and it won`t take much to
keep clouds around. But there is less lift for shower
development across much of the area. Opted to mention drizzle
through the night across the north given the dry air moving in
aloft.
CAA has been on display today, with many interior areas
struggling to hit 70 today. This continues into tonight, tho
flow will slacken. This should bring a fairly cool overnight for
the region. Lows dip into the mid to lower 50s, with some upper
40s possible towards the mountains and western NH.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
With upper low taking center stage once again, expect clouds to
remain throughout and showers to develop late morning. Daytime
heating will be key for these to form off increasing low level
lapse rates. Think instability will be lacking for thunder, but
can`t count out a few rumbles should a vigorous updraft or two
develop. These taper off in the evening w/ loss of daytime
heating, but lighter winds may promote some fog development.
Highs Wed rise to around the same as today, cooler than normal
in the 60s to around 70. Seeing as there will be little airmass
change with the low overhead, another cool night in store Wed
night.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Overview: The 500 mb pattern depicts ridging in place over the
Atlantic and central CONUS, leaving the East Coast in a weak
trough. This looks to result in scattered showers at times, but
with moisture exiting the region generally fair weather and a
weekend warm up will be the more prevalent conditions.
Impacts:
* No significant weather impacts expected.
Details: An upper low remains over the region Thursday so,
while the morning may start mostly dry, we will see scattered
showers and isolated thunderstorms forming in the afternoon.
With high pressure building in at the surface and a drier
airmass moving in aloft, these would be brief and many areas may
stay completely dry. High temperatures remain cool with upper
60s and low 70s south of the mountains, and low 60s to the
north. Clearing skies then allow low temperatures to fall into
the low to mid-50s across the area. The upper low departs Friday
morning and surface high pressure takes full control. Clear
skies and west-northwesterly flow ushers in warmer temperatures.
Highs in the mid 70s to near 80 will make it all the way to the
coast, with low to mid 70s in the mountains and foothills. Low
temperatures Friday night stay a few degrees warmer south of the
mountains as well, in the mid- to upper 50s, whereas the
mountains and the foothills fall into the low 50s once again.
The dry and warming trend continues into Saturday with high
temperatures looking to top out in the low to mid-80s south of
the mountains, and mid- to upper 70s to the north. Moisture
moves back in aloft, but with little in the way of forcing the
only sensible weather this produces is increasing clouds. This
will keep low temperatures warmer on Saturday night, in the
upper 50s to low 60s south and mid-50s north. Sunday looks like
the warmest day, but also the next good chance for scattered
showers as a 500 mb trough builds in. High temperatures look to
be in the 80s south and 70s in the north. Partly cloudy skies
keep low temperatures Sunday night very similar to Saturday
night, albeit a couple degrees warmer.
Global models are in surprisingly good agreement that the upper
trough feature will be overhead Monday, even though they have
different ideas of exactly what it will look like, in regards to
axis location and amplification, at this time range. Because of
this it seems reasonable to keep the NBM`s slight chance PoPs.
The global models do have very different ideas of how long this
trough hangs out, so again having some slight chance PoPs
Tuesday to cover the uncertainty doesn`t hurt.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Scattered to broken MVFR through tonight and
Wednesday. These should be thinner towards the coast, and
thicker in the mountains. Drizzle may also bring vis reduction
in the mountains and foothills tonight into Wed AM. SHRA
develops Wed afternoon, with fog developing Wed night.
Long Term...Outside of the occasional brief afternoon
shower/thunderstorm, VFR will be the prevailing conditions
through Sunday. Westerly winds remain light.
&&
.MARINE...
Short Term...Waves have fallen below SCA, thus its been
cancelled. These continue to run 2 to 3 ft overnight, with winds
slackening further under the passing upper low through Wed and
Wed night. Development of marine fog will be possible, but not
expecting more than patches at this time.
Long Term...High pressure building over the waters will keep
conditions below SCA criteria through Sunday. Westerly winds
remain generally light with gusts 10 to 15 kts.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
Cannon/Baron
Area Forecast Discussion
National Weather Service San Francisco CA
453 PM PDT Tue Aug 20 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 102 PM PDT Tue Aug 20 2024
Slight warming continues today into Wednesday, before a rare August
cold front brings gusty winds, cooler weather, and a chance for rain
Friday into Saturday.
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 102 PM PDT Tue Aug 20 2024
Temperatures will remain near seasonal averages today and tonight as
the region is positioned between an upper level ridge over the Four
Corners region and troughing over the Pacific Northwest. Thus,
expecting mid 60`s to lower 70`s near the coast with temperatures
warming to the upper 80`s across the interior. Tomorrow temperatures
drop below seasonal averages slightly as the aforementioned trough
approaches. Breezy onshore flow continues each afternoon and evening
with gusts up to 20 to 30 mph in the gaps, passes, ridge tops, and
in the Salinas Valley.
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 102 PM PDT Tue Aug 20 2024
By Thursday, the upper level trough will dig into the Pacific
Northwest and kick off a significant cooling trend through late week
and into Saturday (Friday being the coolest). There is high
confidence in this cooling trend as clusters are in good agreement
with the timing and position of the trough. As the front moves
trough the region Friday into Saturday, there is a 10-40% chance of
rain over the North Bay with chances trailing downward as you head
south of the Bay Area. However, rainfall is currently expected to
remain light, not amounting to anything more than a 0.10".
This pattern won`t last long as the trough responsible for the late
week cool down will shift eastward and be replaced by high pressure
over the Eastern Pacific. This will bring a warming trend back to
the region for the upcoming workweek.
&&
.AVIATION...
(00Z TAFS)
Issued at 453 PM PDT Tue Aug 20 2024
VFR with pockets of MVFR-IFR expected overnight. Stratus will
generally return late tonight after 09/10Z as the marine layer
deepens slightly. Moderate confidence that stratus will at least
temporarily reach APC, OAK, SFO, MRY, and SNS. Guidance indicates
some potential for stratus to reach STS but confidence is low to
moderate. Stratus is expected to clear by mid to late morning with
VFR conditions persisting through the remainder of the TAF period.
Gustier conditions continue during the afternoon/evening with gusts
up to 29 knots possible throughout most of the Bay Area. Lighter,
more variable winds return overnight.
Vicinity of SFO...Gusty NW winds continue through the evening before
weakening overnight. Stratus and borderline MVFR-IFR CIGs are
expected to return around 09/10Z with decent model consensus between
the NBM and HRRR in stratus coverage and timing. VFR conditions
return by mid morning and persist through the remainder of the TAF
period. Gusty conditions continue through the evening with gusts up
to 28 knots possible. Winds weaken and become more moderate
overnight before gustier conditions return by the late morning and
continue into the evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR with conditions temporarily becoming
IFR overnight. HREF shows stratus generally staying close to the
coast but confidence has increased that stratus will at least
temporarily reach both MRY and SNS. NBM and HRRR guidance suggest
stratus may develop as early as 10Z with coverage becoming more
widespread beginning around 12-13Z. VFR is expected to return by mid
to late morning and continue through the remainder of the TAF
period. Moderate northwest winds develop during the
afternoon/evening before lighter, more variable winds return
overnight
&&
.MARINE...
(Tonight through next Sunday)
Issued at 453 PM PDT Tue Aug 20 2024
Moderate to breezy winds persist into the late week. Occasional
fresh to strong gusts may develop over the far southern outer
waters through late tonight. A strong, early season upper level
low will dig southward from Alaska reaching the Pacific Northwest
and far northern California late this week. As a result, slight
chances of rain will arrive Friday. Dry weather returns Saturday
and winds ease to become gentle.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Wednesday to 3 AM PDT Thursday
for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
to Pt Pinos 0-10 nm.
Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Pigeon
Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM.
Small Craft Advisory until 3 AM PDT Thursday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...Kennedy
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Area Forecast Discussion
National Weather Service Pocatello ID
214 PM MDT Tue Aug 20 2024
.SHORT TERM...Today and Tuesday.
Looking at current water vapor satellite imagery, there is a deep
upper level low going inland currently on the coast of
Washington. Drier air is filtering into our area in southwest flow
aloft.
Isolated showers and thunderstorms are possible along our eastern
borders with Wyoming this afternoon, but are not that likely.
Expect gusty winds near 30 to 40 mph along with brief, moderate
rain and small hail with any thunderstorms.
Wednesday models show overall dry conditions but winds increase
(gusts near 20 to 30 mph) as the upper level low over the coast of
Washington weakens and moves over northern Idaho. There is a
slight chance of afternoon, isolated showers and thunderstorms
over northern Custer county.
Expect temperatures today slightly above normal (mid to upper 80s
for lower elevations) and temperatures Wednesday slightly below
normal (low to mid 80s for lower elevations).
Wyatt
.LONG TERM...Thursday through next Tuesday.
Look for dry conditions and breezy southerly winds (gusts of 25 to
35 mph) on Thursday out ahead of another upper level low off the
Pacific coast. Windy southerly winds continue Friday (gusts of 25
to 40 mph) with a slight chance of afternoon mountain showers and
thunderstorms. Model clusters continue to be in good agreement in
bringing an upper level low through the area late Saturday into
Sunday. However, the clusters continue to be slightly off on the
depth, strength, and timing of the upper level low. Temperatures
Thursday and Friday will be near normal to slightly below normal.
With good precipitation chances returning, temperatures look to be
8 to 12 degrees below normal on Saturday and Sunday. Expect
temperatures to increase slightly on Monday but still be below
normal. Temperatures increase slightly more on Tuesday (but still
below normal) as high pressure starts building back in over the
area.
Wyatt
&&
.AVIATION...
VFR conditions expected to prevail through the period. Breezy SW/W
winds this afternoon should subside later in the evening and become
light and variable. Winds will again become breezy, similar to
today, around 18Z tomorrow. No precipitation is expected through the
period with only a few mid/high clouds to contend with.
McKaughan
&&
.FIRE WEATHER...
A brief period of marginally critical winds and RHs could be realized
later today but will be localized and short-lived. Slightly cooler
temperatures on Wednesday should keep RHs above critical levels for
most locations tomorrow. On Thursday, we`ll likely get close to
marginal Red Flag conditions once again but probably very localized
once again. Showers and thunderstorms return late in the day Thu but
especially Friday and into the weekend as an upper low moves over
the region. This will bring widespread wetting rains and much cooler
temperatures. The low will depart early into next week while
temperatures slowly moderate once again.
McKaughan
&&
.AIR QUALITY...
Air Quality continues to be good across the whole area currently
except the Stanley area. The Stanley area is being impacted by a
fire due west of Stanley. The HRRR model is showing air quality
degrading more for Custer county, especially northern Custer
county, by Wednesday as southwest flow aloft sets up. A slight air
quality degradation is possible across the rest of our forecast
area, as the HRRR model continues to show smoke from central
California reaching our area in southwest flow aloft.
Wyatt
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...CORRECTED
National Weather Service Pueblo CO
619 PM MDT Tue Aug 20 2024
.KEY MESSAGES...
- Another round of thunderstorms today, some strong to
marginally severe across portions of the southeast plains.
Localized flash flooding possible.
- Daily afternoon and early evening showers and storms are
expected Wednesday night through Saturday.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 214 PM MDT Tue Aug 20 2024
Drier air is evident in WV pics across northern portions of the area
behind yesterday`s departing shortwave to the north. Monsoon plume
still holding strong across southern sections with weak
perturbations riding through the flow. Dew points remain high
across the plains today with readings in the 50s to lower 60s while
dew points have dried out into the 40s across El Paso to around 50
along the Raton Ridge.
For the rest of this afternoon and tonight...active monsoon plume
will generate thunderstorms and push them off into the adjacent
lower elevations through the late afternoon and evening, with
greatest coverage across southern areas where precipitable waters
will remain high (120-140%). Dew points are progged to remain in the
40s along portions of the I-25 corridor, especially the Pikes Peak
region today as lee troughing aides in mixing out some of the low
level moisture. However southeasterly flow along the Arkansas River
and Raton Ridge should keep an axis of higher dew points and CAPE in
place across the southeast plains. HREF mean CAPE values of around
1000-2000 J/kg will be in place east of the I-25 corridor, with 500-
1000 J/kg along the I-25 corridor and points westward. High res
models shift winds southeasterly towards 00z and tries to advect
higher dew points back northward into the Palmer Divide triggering
another round of thunderstorms across El Paso county this evening.
All in all, it looks like another active day for thunderstorms
(though less than yesterday out east) with best coverage across the
mountains, valleys and southern I-25 corridor. Plains will start out
capped, but with some southerly flow increasing this evening overtop
the frontal boundary across southern sections of the area, can`t
rule out a convective cluster working its way southeastward from the
Palmer Divide into the eastern plains overnight. NAMNest and HRRR
runs continue to advertise this scenario. Available instability
won`t be as strong in the overnight hours and the axis of the
stronger southerly low level flow appears to stay to the south and
east, so confidence in storm coverage during the late evening hours
east of the I-25 corridor is low. With deep layer shears 25-30 kts,
a strong to severe storm or two still looks possible through the
evening, with greatest likelihood south of the Arkansas River
valley.
Thunderstorm coverage ramps up for Wednesday as a disturbance
embedded within the monsoon plume moves across southern CO in
southwest flow aloft. Precipitable waters increase out west (up to
150% of normal). Increasing flow aloft nets around 30-35 kts of
shear, with strongest values across northern and western sections of
the area. Can`t rule out a strong to marginally severe storm or
two, though risks will likely transition more towards a heavy
rain/flash flood threat for burn scars and urban areas. Another
round of thunderstorms will push off the mountains into the adjacent
plains in the afternoon, though dew points look slightly lower and
storms are likely to be higher based which may keep things in the
sub severe category. Some smaller hail, gusty outflow winds and
heavy rainfall will be possible. -KT
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 214 PM MDT Tue Aug 20 2024
Wednesday Night - Saturday: For much of the long term period, a
relatively consistent pattern will be in place as monsoon flow
persist. A ridge of high pressure will be in place, and moisture
will be streaming into the ridge and over the region. While no major
forcing is expected, diurnal upsloping and modest orographic
forcing, in combination with the moisture in place, will allow for
daily afternoon rain showers and thunderstorms to blossom. The
greatest coverage of showers and storms will be along the mountains,
where any forcing will be greatest, and especially Wednesday, when a
minor wave gets ingested into the western periphery of the high
pressure. Gusty winds, heavy rain, and lightning are the anticipated
hazards with any more organized thunderstorms. With that all said
though, as instability wanes during the evening hours, any
precipitation present will lessen in coverage. Looking at
temperatures, the warmth continues over south central and
southeastern Colorado. With the ridge sitting over the region, above
seasonal temperatures are expected.
Sunday - Monday: For the end of the weekend and start of next week,
a pattern change is anticipated. A lifting trough will pass
near/over south central and southeastern Colorado Sunday. This wave
will flatten the ridge and scour out some of the moisture as drier
air pushes in behind the wave. Then Monday, as the wave exits, messy
flow will remain in place as the ridge tries to rebuild. With that
all said, drier conditions are expected given the drier air advected
over the region, even despite the heightened forcing from the wave.
The exception to this will be isolated showers and weak storms along
the mountains given some forcing and modest moisture still in place.
Any precipitation present during the afternoon hours will dissipate
during the evening hours as instability lessens. As for temperatures
the warmth is expected to cotinue Sunday as downsloping winds
prevail. Then Monday, a cool down is likely as cold front sags
southward behind the exiting wave.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 550 PM MDT Tue Aug 20 2024
Scattered showers and storms over the higher terrain are expected
to move east across the high mountain valleys, the I-25 Corridor
and possibly across the far southeast Plains through the rest of
the evening. These storms could bring gusty outflow winds and
produce brief MVFR conditions in brief heavy rainfall at the
terminals, with COS having the best chances of seeing storms.
VFR conditions with partial clearing skies through the overnight
hours, with another round of storms expected again Wednesday
afternoon.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...KT
LONG TERM...SIMCOE
AVIATION...MW
Area Forecast Discussion
National Weather Service Springfield MO
611 PM CDT Tue Aug 20 2024
.KEY MESSAGES...
- Below average temperatures and dry conditions expected through
the end of the week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 113 PM CDT Tue Aug 20 2024
The pattern aloft features a broad ridge that puts the greater
Ozarks region in a northwesterly flow pattern. In theory, the
surface high in the Great Lakes region should continue maintaining
easterly ground-level winds. However, a weak shortwave over the
northern Plains induced some showers this morning along with a
relative minimum in surface pressure in Iowa. Perturbations in
pressure from that disturbance have caused wind directions to be
more variable in our area, and the resulting tightening of the
pressure gradient has also caused wind gusts anywhere from 15 to
25 mph this morning, though these gusts should diminish through
the afternoon as the kink in the isobars shifts further east.
Skies are clear in the eastern Ozarks, but early afternoon radar
shows some scattered and weak echoes appearing in western
Missouri. These echoes are associated with the wave moving into
Iowa, though precipitation doesn`t seem to be making it to the
ground due to the dryness of the air column (as seen on our 12Z
sounding). Further to our south and west in northeastern Oklahoma
and south-central Kansas, there is a cluster of slightly stronger
returns. Observations within this region show that some rain has
made it to the ground, but much of this precipitation is likewise
evaporating while falling, leading to more of a haze or mist at the
surface than real precipitation. The HRRR seems to have a good
handle on the current conditions, and indicates that a few
patches of sprinkles could occur across SW MO before synoptic-scale
subsidence and unfavorable thermodynamics completely destroy any
attempts at precipitation. There would be no notable accumulation
with these sprinkles, if they even reach the ground.
Some transient mid-level clouds will overspread the region through
the afternoon, clearing out this evening. The northwest flow regime
will bring below average temperatures, peaking in the mid-80s
to the far southwest and in the low 80s elsewhere; temperatures
may not even break the 80 degree mark further toward central
Missouri. Low temperatures tonight will be an unseasonably cool
upper 50s to low 60s, which is between 5-10 degrees below normal
(normal is around 67 degrees for August 20). Local climatology
comparing 850/925mb temperatures to minimum surface temperatures
suggest that if cloud cover completely clears out by sunrise,
areas as far west as Joplin may even dip below the 60 degree
mark.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 113 PM CDT Tue Aug 20 2024
Little to report in the extended. Wednesday and Thursday`s
temperatures are to remain below normal. Expect high
temperatures in the upper 70s in the eastern Ozarks and mid to
upper 80s moving southwest into the quad-state area. Low
temperatures are forecast to be between the low 60s and low
50s, with the coolest conditions furthest east. The upper-level
ridge and dominant surface high over the Great Lakes will persist
until Friday. As the high finally gets kicked out to the east,
we will see a shift to southerly winds, which will warm things
up a bit. Little to no PoPs (<=10%) through the end of the work
week at this point, though things appear a little less stagnant
by Friday evening.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 610 PM CDT Tue Aug 20 2024
VFR conditions likely to prevail through the TAF period. An area
of scattered mid-level clouds dissipate through the evening
with light easterly winds. Winds become a bit more
east/southeast into Wednesday morning.
&&
.CLIMATE...
Issued at 113 PM CDT Tue Aug 20 2024
Record Low Temperatures:
August 22:
KVIH: 54/2016
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.
&&
$$
SHORT TERM...Camden
LONG TERM...Camden
AVIATION...Perez
CLIMATE...Camden
Area Forecast Discussion
National Weather Service Salt Lake City UT
438 PM MDT Tue Aug 20 2024
.SYNOPSIS...A drier airmass will continue to spread into the area
today. Another monsoon surge is expected Wednesday into the end of
the week while southwest winds increase ahead of an approaching
storm system.
&&
.SHORT TERM (Through 12Z/6AM Thursday)...
Southwesterly flow in place across the area is setting up a
moisture gradient with drier air penetrating into western Utah
while some marginal moisture remains in place across southeastern
Utah, shown on mesoanalysis by the the PW values around 0.3" in
northeastern Utah to around 0.9" down by Lake Powell. This
moisture gradient is supporting shower and thunderstorm develop
along the central spine of Utah mountains with storm motions
toward the northeast limiting the off-terrain storm movement. Thus
some isolated flash flooding remains possible across portions of
southern and eastern Utah this afternoon. Otherwise, the drier
airmass across northern Utah is supporting hot, dry and somewhat
breezy conditions in the southwesterly flow.
On Wednesday, a subtle monsoon wave will move northward out of
Arizona into southern Utah between the ridge to our east and broad
trough developing over the Pacific Northwest. Moisture advection
will increase on Wednesday, but will remain largely limited to
south-central Utah, while a gradient to drier air will remain in
place in west-central Utah. This will support drying of fire
weather fuels across western Utah despite increasing moisture
supporting increasing shower and thunderstorm potential across
southern Utah. There remains a diversity of solutions in the high
resolution models regarding the quality of the moisture advection
in south-central Utah, with the HRRR representing the drier end
of the solution space, while the Fv3 represents the wetter end of
the possibilities. While reality will likely land somewhere in the
middle, cannot rule out either of these more extreme solutions
until we see the quality of the low-level moisture moving in on
Wednesday. Thus flash flood potential will start to increase over
southern Utah on Wednesday. Thus have started ramping up the Flash
Flood Potential Rating (FFPR) into the `Probable` category for
portions of southern Utah on Wednesday, coinciding with the WPC
ERO day 2 upgrade to a Slight Risk.
More models getting on board with a resurgence of moisture
advection into far southwest Utah overnight Wednesday night into
early Thursday morning. Depending on how that evolves with a
potential convergent axis over that portion of the state, heavy
rainfall could redevelop in southwestern Utah off the typical
diurnal cycle during the overnight hours. This potential outcome
will have to be watched closely as well as this could impact urban
areas from St George to Cedar City, as well as Zion NP.
.LONG TERM (After 12Z/6AM Thursday), Issued 427 AM MDT...
Active weather is expected through at least Friday, after which a
cold front will bring cooler and drier weather to the area.
Early Thursday, a strong closed low will be making its way down the
US west coast. As it pushes inland late in the work week, increasing
southwesterly winds are expected, especially across western Utah.
Current ensemble means suggest gusts to 35-45mph in western valleys
on Thursday afternoon, increasing to 50-60mph on Friday afternoon.
Winds could even linger into Saturday depending on when the closed
low passes to our north. We will have to monitor for not only wind
headlines, but also critical fire weather conditions across western
valleys, though this ultimately depends on minimum RH (more details
in Fire Weather section).
While western Utah remains windy and dry on Thursday and Friday,
eastern Utah is actually still influenced by monsoonal moisture,
producing an increased flash flood threat due to showers and
thunderstorms. Prone areas such as slot canyons or areas near recent
burn scars are particularly at risk.
*Update 430PM*: With southwesterly flow deepening across the area,
moisture advection will strengthen and bring higher PW / CAPE
values into central and eastern Utah as well as southern Utah.
The thermodynamic profile will be even more favorable for flash
flooding over a larger area on Thursday, with the one potential
downside being increasing storm motions toward the northeast.
Thus the flash flood threat may be a bit more conditional on
areas of backbuilding or training that develop. Given this
potential continued to expand the `Probable` in the FFPR, which
also corresponds to the more widespread `Slight Risk` in the WPC
ERO.
There is increasing confidence in the track of the aforementioned
low, likely passing across northern Utah or southern Idaho this
weekend. Ensemble guidance is split with regards to timing and
intensity of its associated cold front. Roughly 60% of members favor
a quicker solution, reaching our area late Friday and cooling down
quite a bit to a mean of +5C at 700-mb (from +13C). Another 30%
suggest a late Saturday frontal passage, with a less aggressive
cooldown to +7C. Finally, the last 10% show an even later frontal
passage and warmer temperatures. In summary, below-normal
temperatures are very likely heading into the weekend especially
across northern areas, despite lingering uncertainty in the extent
of the cooldown and timing of the front.
&&
.AVIATION...KSLC...After a period of less certainty on wind
direction early Tuesday evening, higher confidence is noted on
return/maintenance of S winds by ~02-04Z. S winds then begin to
increase and become gusty mid-morning Wednesday into early
afternoon, with gradual shift W to NW by ~20-22Z. Precipitation
currently anticipated to primarily remain east of the high terrain.
.REST OF UTAH AND SOUTHWEST WYOMING...Any remaining precipitation
wanes through Tuesday evening, with winds at area terminals then
largely following a diurnally typical trend. For Wednesday, most
terminals will see increasing SW winds, with many seeings gusts in
the 20-30 kt range mixing in from late morning through the
afternoon. Increasing moisture will also yield elevated convective
threat during the afternoon, with isolated to scattered coverage
most likely at areas east of the I-15 corridor and south of the I-80
corridor. Convection will be capable of producing gusty erratic
outflow winds, lightning, and brief VIS reductions for any stronger
cell that moves directly over a terminal.
&&
.FIRE WEATHER...
Subtle drying trend today will limit shower and thunderstorm
activity over southern and eastern portions of Utah with a
decreased (but not zero) heavy rain threat compared to previous
days. Still isolated heavy rain, lightning, and gust and erratic
winds remain a threat. Moisture will start to increase across
southern Utah again Wednesday, but especially Wednesday night
through Thursday brining increasing shower and thunderstorm
coverage along with increasing potential for wetting rain, as well
as heavy rainfall which could result in flash flooding.
Meanwhile, dry air will intrude across western Utah, creating a
tight gradient in moisture mainly west of the I-15 corridor
through Friday. The combined winds and low RH across far western
Utah will combine to create areas of critical fire weather
conditions. Have issued a Fire Weather Watch for western UT zones
Thursday through Friday, while canceling the watch for Wednesday
in coordination with the Yacc on the marginal fuels given recent
wetting rains, however a day of drying should help fuels be more
primed by Thursday. The best chance for more widespread critical
fire weather conditions will be on Friday as the drier air and
strongest winds overlap.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Fire Weather Watch from Thursday morning through Friday evening
for UTZ478-492-495.
WY...Red Flag Warning from noon to 8 PM MDT Wednesday for WYZ277.
&&
$$
SHORT TERM...Church
LONG TERM...Cunningham
AVIATION...Warthen
FIRE WEATHER...Church
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity