Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/31/23
Area Forecast Discussion
National Weather Service Cleveland OH
951 PM EDT Mon Oct 30 2023
.SYNOPSIS...
A ridge of high pressure will briefly build into the Ohio Valley
tonight before low pressure crosses the region Tuesday into
Tuesday night dragging a cold front across the area. High pressure
will return by Wednesday afternoon and persist through the end of
the week.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 930 PM it appears that the only rain/graupel is located
over interior NW PA. However would not be surprised if we get a
couple snowflakes or maybe some graupel under the lake effect
clouds. Away from NE OH/NW PA skies have become partly cloudy
to clear. This has allowed temperatures to quickly fall into the
30`s with the expectation that much of inland northern Ohio
drops into the 20`s.
Previous Discussion...
Busy start to the work week as unseasonably cold air pours
across the region leading to a widespread, hard freeze tonight
and rain showers eventually mixing with and changing over to
snow showers as the cold air deepens and interacts with the warm
waters of the lower Great Lakes, especially Tuesday night.
Starting off this afternoon, a highly amplified pattern is in
place across the lower 48 characterized by a strong mid/upper
ridge over the west coasts of the US and Canada and a broad
downstream mid/upper trough over the Plains and Midwest. The
initial cold front ushering in this cold airmass is well east
of the region as of late this afternoon as the associated
surface low moves off the coast of New England. This is leading
to cold air advection within a cyclonic flow regime, and this
combined with lingering wraparound moisture, 850 mb temps
cooling to -6 to -8 C, and favorable NW fetch across Lakes Huron
and Erie, is bringing lake effect rain showers. The greatest
coverage of these showers currently extends from north central
Ohio through the higher terrain of the primary snowbelt in NE
Ohio and NW PA. A recent flare up in this activity appears to be
tied to a weak mid-level shortwave rotating through the
cyclonic flow, and once this passes, expect the steadiest
showers to become confined to areas east of Cleveland through NW
PA (after 00Z).
Moving into tonight, an impressive mid/upper shortwave and
associated vort max will dive into the Upper Midwest acting to
further deepen the trough axis and big cold pool over the
western Great Lakes. The boundary layer flow will back ahead of
this feature, and this combined with shortwave ridging and
associated surface high pressure briefly building in from the SW
will result in the bands of lake effect becoming less organized
and lifting farther NE as the night goes on. The rain showers
will mix with snow over the snowbelt of NE Ohio and NW PA
tonight, and could see a trace to a couple of tenths over the
highest hilltops such as Chardon and Greenfield Townships.
Outside of the lake effect, skies will clear out as the high
builds in, and this combined with the cold airmass will lead to
a widespread freeze. Lows in the mid/upper 20s are expected in
most inland areas from NW and north central Ohio through the US
30 corridor, with low 30s in NE Ohio and NW PA, so continued the
Freeze Warnings for all areas despite slightly "warmer" lows
near the lakeshore. This will officially end the growing season.
As the boundary layer flow continues to back Tuesday morning,
lingering lake effect rain/snow showers over the I-90 corridor
from Lake County through Erie, PA will continue to lift north
and should be out over Lake Erie by 16Z as the flow becomes
220-240 degrees (true SW flow). Increasing low-level convergence
as the flow backs combined with long fetch could consolidate a
fairly intense band over the middle of the lake, but impacts
from this will stay in western NY through the afternoon. This
will lead to a mostly dry but cold day outside of the morning
precip east of Cleveland. Clouds will increase from west to east
in the afternoon as the aforementioned shortwave and vort max
rotates into Lower Michigan. This feature will bring the most
interesting weather of the near term forecast with the potential
for the first accumulating snow of the season (see below). Highs
Tuesday will stay in the low/mid 40s, so it will be another cold
day despite the drier conditions and partial sunshine.
Regarding the snow potential Tuesday evening and Tuesday night,
impressive mid-level PVA will accompany the shortwave itself.
This will support rain and snow showers areawide moving in from
west to east Tuesday evening. The mid-level low and associated
vort max will drop from southern Lower Michigan into the Ohio
Valley between 00 and 09Z Wednesday. As it does, it will drag a
reinforcing cold front/surface trough SE across the area. The
good dynamics and sharp frontal boundary will lead to bands of
rain/snow showers progressing east/southeast through the region
Tuesday evening ahead of the front/trough. Given the strength of
the mid-level lift, temperatures should wet bulb down quickly
leading to a transition to full snow after sunset. This could
put down a trace to a couple of tenths anywhere, so increased
PoPs areawide Tuesday evening into early Tuesday night. The main
story however will be a burst of intense lake effect. The
aforementioned band over Lake Erie will push onshore with the
trough, and NAM BUFKIT forecast soundings show very favorable
conditions for a burst of brief heavy snow early Tuesday night.
Boundary layer moisture deepens quickly ahead of the trough with
lake induced equilibrium levels progged to increase to nearly
20,000 feet. This combined with a 23 C lake to 850 mb delta T
and strong cold air advection (850 mb temps -8 C) will support
extreme instability with lake induced CAPE values in the
1000-1500 J/Kg range supporting thunder. This all combined with
sharp convergence along the advancing surface trough will lead
to a burst of heavy precip as the band pushes onshore and
advances SE. Expect a transition to all snow rapidly over the
highest elevations of the snowbelt east of Cleveland, but lower
elevations and areas near the lakeshore will stay a rain snow
mix longer (the lakeshore will probably not see any snow). In
terms of amounts, the main limitation is the short duration.
HREF members as well as the NAM12 and RAP move the band SE
quickly between about 02 and 06Z, but the rates will be high for
a time with thunder and lightning as mentioned above. This
could put down a quick 1 to 3 inches in the highest elevations
with up to an inch elsewhere. It will certainly be a quick
hitting burst of snow, but it will be potent for a few hours,
especially for the first snow of the season. There will likely
be a lull behind the main squall as the flow quickly veers NW
and some subsidence moves in, but continued boundary layer
moisture, cold air advection, and favorable fetch from Lake
Huron could generate additional bands in the 09-12Z timeframe,
although less organized given shear seen in forecast soundings.
This could bring additional snow into the secondary snowbelt
(Medina, southern Cuyahoga, Summit, and Portage) as well as
parts of the inland primary snowbelt. At this time, went with
2-5 inch snow amounts over the highest hills of northern Geauga
County and southern Erie County PA with generally 1-3 inches in
the rest of the primary snowbelt and into the secondary
snowbelt. Lakeshore areas will see little to no snow. If the
band is slower to move, then higher amounts are possible. A
Winter Weather Advisory is looking increasingly likely for
portions of the area Tuesday night into Wednesday morning.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Winds will turn southwesterly as Canadian high pressure moves into
the Appalachians with the CWA drying out except for lingering
precipitation in far NW PA. The return flow signals a pattern
change, and will see the beginnings of warm air advection bringing
850mb temperatures back above 0C. Thursday is still on the cool
side, but trending gradually upwards with some peaks of sun. Flow
aloft begins its transition to a zonal pattern as well.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Friday and Saturday back into the 50s in the southwesterly flow.
Some inconsistencies in the extended with a cold front/low pressure
system for the end of the weekend time frame, but carrying some low
end POPs for now Saturday night into Sunday, but expect to get into
some cooling once again for Sunday and beyond.
&&
.AVIATION /00Z Tuesday THROUGH Saturday/...
All reporting sites are reporting VFR conditions. However there
is likely some patchy MVFR/IFR conditions with the showers that
are located over NE OH into NW PA. Drier air continues to flow
into the region overnight with all ceilings remain VFR away from
any remaining showers. The next upper level trough swings cross
the region late Tuesday afternoon into Tuesday night with a
significant increase in rain/snow becoming all snow after
sunset. IFR and lower conditions should occur as the trough axis
arrive late Tuesday afternoon into the evening.
NW winds of 5-15 knots will decrease through the evening. For
Tuesday expect W-SW winds that increase to 10 to 15 knots
during the afternoon.
Outlook...Non-VFR possible Tuesday night through Wednesday in
lake effect rain and snow.
&&
.MARINE...
Northwest winds 15-25kts ease late tonight into Tuesday before
turning southwesterly 10-15kts for a few hours ahead of the next
cold front. Wave heights subside slightly during this time, before
kicking back up again behind the cold front Tuesday night out of the
northwest at 15-25kts. High pressure moving south of Lake Erie
Wednesday translates to winds turning southwesterly again Wednesday
night into the first part of the weekend, reaching 15-25kts Thursday
at their peak.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Freeze Warning until 10 AM EDT Tuesday for OHZ003-006>014-
017>023-027>033-036>038-047-089.
PA...Freeze Warning until 10 AM EDT Tuesday for PAZ001>003.
MARINE...Small Craft Advisory until 4 AM EDT Tuesday for LEZ145>149.
&&
$$
SYNOPSIS...Garuckas/MM
NEAR TERM...Garuckas/MM
SHORT TERM...26
LONG TERM...26
AVIATION...MM
MARINE...26
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
615 PM CDT Mon Oct 30 2023
...Aviation Update...
.DISCUSSION...(This evening through Monday)
Issued at 452 PM CDT Mon Oct 30 2023
--- KEY MESSAGES FOR THE ENTIRE 7-DAY FORECAST:
(including all further discussion of Days 3-7 Thurs-Mon)
-- Key Message 1-sentence summaries (see paragraphs immediately
following for more details by topic):
* KEY MESSAGE 1:
Although it should be a dry frontal passage, a moderately-strong
cold front will surge southward across our coverage area (CWA)
overnight, featuring at least a brief period of 30-40+ MPH wind
gusts and making for a very cold Tues AM especially in terms of
single digit (probably above zero) wind chills.
* KEY MESSAGE 2:
More typical fall weather lovers take heart!: Following Tuesday`s
cold, we will rebound quickly with all days in the remainder of
the 7-day forecast featuring more typical (for early-Nov) highs in
the 50s-60s (and even an occasional 70 possible in our far south-
southwest zones).
* KEY MESSAGE 3:
Our forecast is all but "guaranteed" dry through AT LEAST Thurs
night, and probably a bit beyond, but at least low-end/still
fairly "iffy" chances for RAIN (NOT snow) appear a bit more
favored by around Sun night-Mon (although most areas have
maintained no mention of any mentionable/15+ percent/ rain
chances in this latest forecast).
-- Key messages details corresponding to #1-3 above:
* KEY MESSAGE 1 MORE DETAILS:
Although nothing "crazy" in terms of wind speeds, some brief peak
gusts up to around 45 MPH cannot be ruled out with/just behind the
initial cold frontal surge overnight, and this moderately-strong
wind potential has been introduced to our Hazardous Weather
Outlook (HWOGID). As for the single digit wind chills likely
Tuesday AM, will also maintain this previously-introduced
inclusion in our HWO given that it will be some of the coldest
wind chills of the season-so-far (but thankfully still quite a
ways short of our official Advisory criteria of -20 degrees). See
short-term specific paragraphs below for more.
* KEY MESSAGE 2 MORE DETAILS:
Hopefully those who perhaps thought more "true"/seasonably-
pleasant fall weather was done for, take heart! Once we get
through Tuesday`s Halloween cold, a prolonged stretch of
seasonably-mild weather commences Wednesday, with highs mainly
50s-60s most areas for the rest of the 7-day, and even a few 70s
possible especially near/south of the KS border mainly Friday
onward. Overnight lows will follow suit, climbing from the
teens/20s these next couple of nights, to mainly 30s (and maybe
even some low 40s) especially Thurs night onward.
* KEY MESSAGE 3 MORE DETAILS (including overview of upper air
pattern):
With broad/low-amplitude ridging prevailing from the western CONUS
into our Central Plains region through most of the week, our
forecast is all but "guaranteed" dry through AT LEAST Thursday
night. Beyond that, while our official forecast remains dry at
this time, it is a touch harder to guarantee it staying that way
perhaps as early as Fri night-Sat, as both the latest ECWMF/GFS
show a low amplitude wave passing mainly just to our
north...perhaps just close enough that especially northern zones
will need monitored for some future low rain chances. Then,
following what looks to be another fairly solid break from rain
chances Sat night-Sun daytime (as we reside "in between" waves),
our next chances for POSSIBLE rain could arrive with the next
disturbance currently slated to arrive from the west-northwest
around Sun night-Monday. However, with model signals for any rain
(and especially any meaningful amounts) still far from
unanimous/truly high confidence, the multi-model (NBM) blend used
to populate our longer-range forecast has kept Sunday night dry
for now, and only assigned slight chances (20%) to a few of our
far north-northeastern counties for Monday daytime (obviously
plenty of time for adjustments that far out in time).
-- Biggest changes with this latest 7-day forecast versus the
previous (night shift) issuance:
Honestly, those watching closely will note very little change, but
if anything:
1) Wind speeds (mainly gust) potential for tonight was bumped up
slightly...mainly to get more 40 MPH potential in the forecast.
2) High temperatures were nudged down very slightly (1-2 degrees)
most areas for Tuesday, and conversely were nudged very slightly
upward for especially Wed-Fri, as there is zero doubt that our
temperature recovery from "winter" back toward fall will be quite
noticeable.
-- SHORTER TERM FORECAST DETAILS FOCUSED SOLELY ON THESE NEXT 36
HOURS (through late Tues night/Wed AM):
- CURRENT/RECENT WEATHER SCENE AS OF 4 PM:
Today has turned out very much as expected from previous/inherited
forecast package. Under widespread sunshine, high temps are on
track to top out between 44-49 degrees most areas, with a few
extreme southwestern counties (such as Phillips/Rooks) barely
tagging 50. If anything, westerly gusts were just a touch stronger
than anticipated at times with sporadic gusts to 25+ MPH at times
(mainly in our Nebraska counties, but overall wind today have
averaged sustained 10-15 MPH/gusts to around 20 MPH). In the mid-
upper levels, water vapor satellite and short term model data
clearly highlight a vigorous "Clipper" disturbance tracking
southeastward across the ND/SD/MN border area this afternoon,
while at the surface the leading edges of the fairly strong cold
front headed our way tonight is headed south through SD.
- THIS EVENING-TUES AM:
As noted by preceding forecast, sometimes these strong cold-season
frontal passages kick off a brief round of "surprise"
flurries/light snow, but have maintained a dry/snow-free forecast
as even flurry potential should mainly focus AT LEAST 50-100 miles
north-northeast of our CWA (let alone any measurable snow
potential which should focus closer to 200 miles northeast of our
CWA). That leaves moderately-strong north winds and seasonably-
frigid late night/early Tues AM wind chills as by far our main
issues. Prior to 10 PM, nearly our entire CWA will remain south of
the front, experiencing continued west-southwesterly breezes
mainly only 5-15 MPH. However, between mainly 10 PM-2 AM, this
strong front will race southward across our CWA it`s passage
marked by sustained northerly winds at least 20-25 MPH/and gusts
at least 30-40 MPH. Although it would certainly be the exception
(as supported by latest HRRR gust progs), at least brief/sporadic
gusts to 45 MPH cannot be ruled out especially along/just behind
the initial frontal surge. It might not be a bad idea to secure
any loose objects/trash cans overnight...just in case. Once the
initial pressure-rise passes through, winds will tame down a bit,
but even at sunrise sustained speeds OF 10-20 MPH/gusts 20-30 MPH
will be present (lightest west/highest east). Meanwhile, strong
cold air advection behind the front will drop overnight (near to
just after sunrise) low temps down into the 16-21 range most
areas. These temps, in combo with the aforementioned winds, will
promote late-night/early AM wind chills well down into the single
digits (above zero). While far from official Advisory criteria
(-20), we are not yet acclimated to wind chills this cold so early
in the season, and thus will continue inclusion in the HWO.
- TUESDAY DAYTIME:
This is almost assuredly the coldest day we will see for quite
some time, and high temps were nudged down slightly with most of
the CWA aimed 33-38 degrees, and any rogue 40 probably in far
southwest around Rooks County. However, on a positive note, winds
will be on a slow-but-steady DECREASE through the day as surface
high pressure moves across, and skies will be mostly sunny. By
mid-afternoon, wind speeds will mainly be down to 5-10 MPH as
direction transitions from northerly, to westerly to eventually
southerly Tues evening on the back-side of the departing surface
high.
- TUESDAY EVENING-OVERNIGHT:
The good news for Halloween trick-or-treaters is that although
the late afternoon-mid evening time frame will be chilly for sure,
we`ve certainly endured worse over the years. Focusing on the 6
PM-10PM time frame, winds will average no more than 5-10 MPH,
actual temps will fall through the 20s, and wind chills will
prevail only slightly colder (teens/20s). As the night wears on,
southerly breezes will pick up a bit with sustained speeds more so
10-15 MPH/sporadic gusts to around 20 MPH. While these breezes
will stabilize the late-night temperature drop, actual lows are
aimed pretty similar (maybe BARELY) warmer than tonight, with most
areas expected to bottom out within a few degrees either side of
20.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 602 PM CDT Mon Oct 30 2023
Main concern in this TAF window will be the cold front moving
through the area in the 04-05Z timeframe. A brief window of LLWS
is possible ahead of the push of strongest surface winds. Peak
gusts over 30kts are likely through daybreak on Tuesday.
A few midlevel clouds are possible during the early morning hours
on Tuesday, but VFR conditions should prevail.
Winds decrease late Tuesday morning and eventually become
light/variable by late Tuesday afternoon.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Pfannkuch
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Goodland KS
714 PM MDT Mon Oct 30 2023
.UPDATE...
Issued at 709 PM MDT Mon Oct 30 2023
Overall forecast remains on track, the main changes that were made
were to up wind gusts with the passage of the overnight front. RAP
and HRRR both suggest weak pressure rises of 3-5mb over three
hours with the passage of the front. The best cold air advection
looks to occur across central and southern Nebraska into NC/NE
Kansas where the stronger wind gusts look to occur. For the
northeast portion of the CWA wind gusts of 25-35 mph are possible
with the strongest across Red Willow, Norton counties.
&&
.SHORT TERM...(This afternoon through Tuesday)
Issued at 1139 AM MDT Mon Oct 30 2023
Latest upper air analysis shows northwest flow over the High
Plains. Water vapor imagery shows dry northwest flow, with some
high clouds over the Northern Plains. At the surface a weak cold
front is seen approaching South Dakota. In addition the snow from
yesterday can be seen. Due to the lack of any WAA, the snow field
has not reduced noticeably in size. The rest of today the light
winds will continue.
Tonight the west winds will turn to the northwest ahead of a weak
cold front and surface high pressure moving in from the north. Due
to the dry environment, am not expecting any precipitation with
the frontal passage.
Tuesday the northwest winds will remain light, then turn to the
south behind the exiting surface high pressure in the afternoon.
Meanwhile temperatures will be a little cooler than yesterday,
especially over the eastern part of the forecast area.
.LONG TERM...(Tuesday night through Monday)
Issued at 123 PM MDT Mon Oct 30 2023
This part of the forecast will continue to be dry. There will be
several cold front passages. However, the environment will be dry
enough to deter precipitation formation.
The upper level ridge continues to dominate the weather pattern
over the western CONUS. A weak cold front moves through Wednesday
accompanying a short wave trough rounding the ridge to the west.
After the cold front temperatures warm further as a stronger short
wave ridge approaches the forecast area through the rest of the
week.
Relative humidity values will fall to the upper teens over the
southern part of the forecast area Wednesday and Thursday
afternoons. However the winds continue to look light. However
there could be sporadic gusts Thursday afternoon.
Friday the models disagree regarding how fast the next short wave
trough moves through. The ECMWF and GEFS seem to agree with a
faster frontal timing of Friday, while the operational GFS has
the front moving through Friday night. Have more confidence in the
earlier frontal arrival. The earlier frontal arrival should
result in the relative humidity values being above 20%. Even if it
does not, the front moving through should prevent the relative
humidity values from falling too far into the teens. Wouldn`t be
surprised if the winds are breezy along and behind the front.
Another cold front may move through Sunday night. This front may
be stronger, bringing another round of cold air to the forecast
area.
Due to the jet stream being mainly north of the forecast area, any
precipitation associated with the upper level short wave trough
passage will be north or east of the forecast area (following a
trough as it deepens to the east).
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 452 PM MDT Mon Oct 30 2023
Westerly winds will be present at each site to start the period. A
cold front moves through the area late this evening turning the
wind to the NNW and bringing a brief period of 20-25+ winds to the
area; the strongest winds currently appear to favor the KMCK
terminal where the greatest pressure rises will reside. In wake of
the front winds will weaken before becoming light and variable
before finally becoming more southerly by the end of the period.
LLWS looks to affect each terminal with the incoming frontal
passage. RAP soundings at KMCK suggest the LLWS should develop at
just after TAF issuance and may last through at least sunrise.
Guidance has also been consistently hinting at some stratus
developing around sunrise; its not an overall strong signal but
it has been consistent which has gained my attention. Low level
moisture currently favors the KGLD terminal so went ahead and
added in a tempo to account for it. Will monitor through the
evening to see if it will be warranted for KMCK come 06Z TAF
issuance.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...Trigg
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...Trigg
Area Forecast Discussion
National Weather Service Green Bay WI
1051 PM CDT Mon Oct 30 2023
Updated aviation portion for 06Z TAF issuance
.UPDATE...
Issued at 921 PM CDT Mon Oct 30 2023
The clipper low was situated N of MSP this evening, and the area
of max pressure falls suggested it would continue to shift SE. WV
imagery showed a sharp upper trough moving through NW MN. The
radar mosaic showed an initial band of snow moving through eastern
MN in association with the cold front, somewhat of a lull behind
the leading band, then more snow with the developing deformation
zone in NW MN. Models still show the low passing through our far
southwest counties late tonight/early Tuesday, with perhaps a bit
of a northward shift in the QPF. Did not make any major changes to
the forecast, with just a slight increase in snowfall amounts.
Agree with the previous shift that impacts with this system could
certainly warrant an advisory, but surrounding offices favored
continued messaging with Special Weather Statements and social
media this evening. Will pass on concerns to the night shift, and
if trends support it, they can issue a short-fuse advisory before
the commute begins.
Have updated the SPS to expand the coverage area a bit farther
north and east, along with a slight increase in snowfall amounts.
&&
.SHORT TERM...Tonight and Tuesday
Issued at 214 PM CDT Mon Oct 30 2023
Key Messages:
- First widespread accumulating snow of the season (70-90% chance)
remains expected from late tonight into Tuesday morning with a
general accumulation of 1 to 2 inches expected.
- The probability for 1 inch or greater during this event has
stayed relatively steady (50-70% chance) over central Wisconsin,
but has decreased slightly over the Fox Valley (20-40% chance).
- Considering it is the first snow of the season and the morning
commute will be affected, concerns are heightened for above
normal impacts with this magnitude of snowfall.
- Cold and breezy conditions expected for Halloween with temps in
the 30s, wind chills in the 20s, and gusty winds to 25 mph.
Forecast Details:
The latest RAP analysis and satellite/radar imagery show a surface
ridge axis moving across the western Great Lakes early this
afternoon. Scattered to broken convective clouds persist this
afternoon thanks to steep low level lapse rates within thermal
troughing. Combined with gusty west winds, wind chills remain in
the teens and 20s this afternoon. Meanwhile, a dynamic shortwave
and associated surface low are digging southeast across south-
central Canada and poised to enter the region late tonight.
Forecast concerns mainly revolve around potential snow
accumulations and impacts with this system.
While some strato-cu will persist into the evening hours, clouds
will be increasing this evening as the potent shortwave quickly
moves into the northern Mississippi Valley. Strong QG forcing
along with low level convergence with the surface low will then
pass across central WI to the Fox Valley after midnight through
late Tuesday morning. Timing of arrival of the snow looks to have
slowed slightly, while the ending timing has sped up compared to
the previous forecast.
Transient, but strong lift will occur for a few hour period when
the strongest forcing arrives late tonight into Tuesday morning.
The strong lift will be partially offset by a relatively dry
airmass (precipitable water values 1 standard deviation below
normal). Still though, precip amounts have remained relatively
steady though perhaps shifted south slightly. 1-2" snowfall remains
forecast from central WI to the Fox Valley. Locally higher amounts
are possible, particularly over central Wisconsin.
Timing of the snow remains less than ideal and is likely to impact
the morning commute. Up to an inch of snow may already have fallen
over central WI by 7 am and the higher snowfall rates will be
approaching the Fox Valley during the peak of the morning commute.
Despite these concerns, will refrain from issuing a Winter Weather
Advisory after coordinating with surrounding offices. Will instead
handle the situation with an SPS and later shifts can issue an
advisory if necessary.
After the snow ends, north winds will be gusting from 20 to 30 mph
on Tuesday afternoon. Wind chills will likely remain in the 20s
in the afternoon.
.LONG TERM...Tuesday Night Through Monday
Issued at 214 PM CDT Mon Oct 30 2023
Snow showers or flurries near Lake Michigan should end Tuesday
evening as the sharp upper trough moves quickly out of the Western
Great lakes. There should be some clearing overnight as a surface
high moves across the area. Cold advection and clearing should
make for a very cold night, with lows around ten to fifteen degrees
cooler than normal. If there is any snow left on the ground across
central Wisconsin a few places there could get near record lows.
Middle and high clouds will return Wednesday as a weak upper trough
goes by. The air will be dry enough to prevent anything more than
virga. Temperatures should be several degrees higher than Tuesday.
The upper flow become nearly zonal by the end of the week, with
some shortwaves moving through the fast flow. This sort of regime
makes it difficult to time features. Friday and Sunday look like
they have the best chance of seeing precipitation. It may be cold
enough for some snow across the north Friday, but Sunday might be
warm enough for all rain. Temperatures for the end of the week
and look to be near or a little below average.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1044 PM CDT Mon Oct 30 2023
A clipper low pressure system will cause light to moderate snow
to overspread the region from west to east overnight into early
Tuesday. Conditions will quickly lower to MVFR/IFR as the steady
snow arrives. Areas south of HWY 29 will be most impacted, but
steady snow may even impact the RHI TAF for a few hours into early
Tuesday. Most of the snow will end during the late morning/early
afternoon, except in the lake-enhanced areas of far northern and
eastern WI.
Winds will be fairly light overnight, but north winds gusting to
20 to 25 knots will develop as the low pressure system shifts
east in the late morning/afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.........Kieckbusch
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Grand Rapids MI
955 PM EDT Mon Oct 30 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 955 PM EDT Mon Oct 30 2023
While areas of light snow should develop before daybreak as
increased moisture and lift arrives near the bottom of the DGZ,
models remain lackluster on snow amounts. Travel impacts appear
unlikely for the morning commute.
Road slush and a respectable accumulation on grass and trees are
plausible during Tue afternoon through trick-or-treat time for a
portion of West Michigan. The 12Z HREF suite and subsequent HRRR
and RRFS runs have consistently placed the greatest probability
of multi-inch accumulations north of Holland-Hudsonville toward
Ludington, centered in or near Oceana county. This small area just
north of the surface low is where there may be an overlap in
where the low`s deformation zone pivots, plus where lake-enhanced
moisture in the DGZ layer is transported. An easterly component of
surface winds in this area may allow colder temperatures and snow
to stay closer to a warm Lake Michigan than is typical this time
of year. One caveat could be a tendency for more graupel very near
the lake, which may reduce snow totals in a smaller subset of
this favored area. Thundersnow and isolated totals over 3 inches
can`t be disregarded as a possibility, along with potential weak
tree limb breaks and isolated power outages from the weight of
0.5+ inch of water content.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 341 PM EDT Mon Oct 30 2023
-Chance of Lake Effect Snow Showers Tonight-
Some hi-resolution model guidance continues to suggest that surface
convergence along the lakeshore develops overnight tonight as
westerly winds over the lake interact with the shoreline and light
winds expected over land. Have chance PoPs to account for this
overnight tonight, however there is some uncertainty in regards to
coverage given that deep layer moisture is not impressive,
especially prior to 06z. Generally any snow showers would be
near/west of US131 with a dusting to a few tenths of snow possible
on grassy surfaces.
-Snow Expected Tuesday-
The upper-level low responsible for our next system arrives in
southern Wisconsin by 12z and traverses lower Michigan throughout
the day. This system will work in tandem with sfc-850 mb delta T
values near to exceeding 20C to provide notable lake based
instability to provide a great opportunity for a lake enhanced
snowfall event across the region.
Snowfall totals are generally expected to be in the 1-3 inch range
for most with the highest totals expected across our northwest CWA
where both deep layer omega values and DGZ saturation are greatest
in the 15z Tue to 00z Wed timeframe, especially after 18z. However,
some hi-res guidance wants to paint a more aggressive picture with
QPF as moisture is advected off of the lake resulting in the
potential for higher amounts. The favored region if this occurs is
between I96 and US10 in the vicinity of US131 given the southwest
flow expected off of the lake as well as the higher elevation of
central lower Michigan. The other notable source of uncertainty is
related to thermal profiles and ground temperatures. Warm ground
temperatures and low-level thermal profile may help to mitigate any
accumulation, particularly outside of any heavier bands that
occur, given that this will be a primarily daytime event.
Close to the lakeshore, some rain may mix in with any snow becoming
all rain over the lake due to the warming effect of the marine
layer. In terms of impacts, where heavier bands occur, brief
accumulations on roads and brief reductions in visibility are
expected. Some thunder is possible over and in the lakeshore
vicinity of Lake Michigan Tuesday as the cold pool associated with
the upper-level trough passes overhead generating a few hundred J/kg
of MUCAPE over the lake.
-Snow Near The Lakeshore Tuesday Night-
As the low exits the area Tuesday night snow winds down across the
inland portions of the CWA with lingering snow showers near the
lakeshore as deep layer moisture lingers with wind convergence at
the lake-land interface, with occasional snow showers continuing
through the night, albeit with higher chances the first half of
the overnight period.
.LONG TERM...(Wednesday through Monday)
Issued at 341 PM EDT Mon Oct 30 2023
Some light lingering snow showers or flurries will be possible near
the lakeshore for the first half of Wednesday as residual lake
effect diminishes and moves onshore with a WNW wind. This should not
cause any impacts, other than any icy patches from any wet roads
that might freeze. Otherwise, we will see some sunny breaks develop
as the entire system moves out, and ridging moves in.
The ridging will dominate our weather until later Friday, keeping
dry conditions and moderating temperatures. Once the ridge moves by,
the overall weather pattern will shift to that of a more zonal flow
over the northern portion of the country, including the Great Lakes.
The zonal flow will bring a mild and somewhat unsettled weather
pattern then from Friday night through next Monday. Short waves
embedded in the flow will periodically move through, bringing
chances of rain with each of them. Exact timing and amounts are
uncertain this far out. It will not be raining all of the time by
any means, with plenty of dry breaks between waves. It does not look
look like we will see heavy rain with these system as the Gulf does
not really look to be supplying much, if any, moisture to the area
based on the the low level flow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 630 PM EDT Mon Oct 30 2023
Primarily VFR conditions are expected at most of the terminals
overnight. The exception to this is at KMKG where some lower
clouds and redevelopment of lake effect light snow showers and
flurries will cause conditions to deteriorate to MVFR late
tonight.
Conditions will slowly deteriorate from mostly VFR to MVFR and
then IFR at some of the terminals from around midday Tuesday
through the afternoon as cigs deteriorate and snow showers
develop. Snow showers will become most prevalent at our western
terminals Tuesday afternoon where brief reductions to LIFR are
possible in heavier snow showers. The most significant snow
showers are expected from mid afternoon through mid evening
tomorrow.
&&
.MARINE...
Issued at 341 PM EDT Mon Oct 30 2023
The ongoing Small Craft Advisory is verifying well as persistent
small craft conditions have been reported at many of our observation
sites much of the day. A lull in winds and waves is expected of
around 10-12 hours overnight tonight into the morning hours.
However, given that waves ramp up again Tuesday afternoon due to the
gales over the lake, have elected to extend the current Small Craft
Advisory south of Pentwater until 04z Wednesday to cover both
today`s event and Tuesday`s. Fetch doesn`t look nearly as
favorable from Pentwater to Manistee for elevated waves at this
time so will not extend for that zone. Advisory conditions then
remain likely for much of the rest of the week as is common this
time of year. Waterspouts are also possible Tuesday into early
Wednesday as notable overlake instability interacts with the passing
low pressure system.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until midnight EDT Tuesday night for
LMZ844>848.
&&
$$
UPDATE...CAS
SHORT TERM...Thomas
LONG TERM...NJJ
AVIATION...Laurens
MARINE...Thomas
Area Forecast Discussion
National Weather Service Gray ME
1141 PM EDT Mon Oct 30 2023
.SYNOPSIS...
Cool conditions will persist through the middle of the week
before a warming trend arrives by late week and next weekend. A
storm system exiting into the Canadian Maritimes tonight will
result in periods of upslope snow showers. High pressure then
will return for Tuesday through the remainder of the week with
mainly dry conditions. A cold front then approaches late next
weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
1130pm Update...Adjusted the chance for snow showers down
overnight in the mountains. Greatest forcing along a weak trough
following up tonight is expected to go a bit further north. This
will reduce the potency here. Meanwhile, skies have cleared
across much of the interior and gradually the coast. While CAA
will cause temps to plummet, it should also be drying out
surfaces.
715pm Update...Little update here mainly to adjust temperatures.
Parts of central Maine have fallen through the mid-30s and are
approaching freezing. Precip across the CWA is lightening, with
the back edge through the Whites at this time. It`s possible a
few of these central ME locations see a brief flurry, but
otherwise a drying trend is expected overnight. Area roads are
wet however, and temperatures falling at or below freezing may
cause some slick spots until they dry out by morning.
HRRR/NAMnest runs have been in agreement of a line of snow
showers approaching the international border around midnight
tonight. These may pack a punch in the way of a brief heavy snow
shower and gusty winds. At this time, not expecting impacts
outside of the mountains. This will result in reduced
visibility and a fresh dusting mainly where snow fell today.
Update...
Quick update to remove Winter Weather Advisories headlines which
expired as of 20Z. Patchy freezing rain and snow will gradually diminish
over the higher terrain before upslope snow showers take hold
overnight.
Low pressure over the Gulf of Maine as of 19Z will continue to
exit to our east overnight. The latest HRRR has the precipitation
moving to our east by this evening.
With cold air advection and a northwesterly flow developing
overnight, expect upslope snow showers across the mountains.
Went above most modeled pops with light additional accumulations
of snow possible across the higher peaks. It will be a chilly
night, especially where there is a fresh snowpack with min
temperatures ranging from the 20s in the north to the 30s in the
south.
Model consensus is now in relatively good agreement intensifying
an area of low pressure off the Mid Atlantic coastline Tuesday
night. Most of the synoptically driven precipitation will remain
off the coast during the short term portion of the forecast. It
will be the coldest night of the year with teens in the north
and min temperatures in the 20s to near 30 in the south.
Portland is forecast to drop to 31 degrees Tuesday morning. If
this occurs, it will be the second latest freeze on record for
the Forest City.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Upslope cloudiness will continue in the mountains on Tuesday
with mostly sunny conditions elsewhere. H8 temperatures around
minus 8C will lead to a chilly day despite some sunshine.
Afternoon temperatures will top out in the 30s north to the 40s
south.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Overview...
A coastal storm passes offshore on Wednesday as an upper level
trough swings through New England. High pressure builds in from
the southwest on Thursday, bringing a warming and dry pattern
into early next weekend. A cold front then approaches from the
north either Saturday night or Sunday, bringing a return to
cooler temps and the chance of showers.
Details...
The coastal storm we`ve been monitoring over the last few days
looks to be passing safely out to sea, east of the Gulf of
Maine. This keeps any precipitation associated with system
offshore, but at the same time the upper level shortwave helping
to drive this system swings through New England and brings the
chance for rain and snow showers, especially across western and
southern areas. These would mostly be light and scattered and
nature, providing little more than the first flakes of the
season to most people. The global models are starting to show
this more consistently, with the GFS and its ensembles now
joining the Euro/Euro Ensembles in the last couple runs. The
high res guidance is still not showing much, but the expectation
is that they will start to come around more in line with
favorable forcing moving through in the middle of day. Showers
may start as rain, but temps would quickly cool toward wet bulb
temps and at least mix with flakes on Wednesday. This system
then swings offshore and moves away during the evening hours.
Cold air flows in behind the passing storm, with lows dipping
into the 20s in most spots. High pressure then builds in from
the southwest by Thursday, bringing milder air and sunnier
conditions by Thursday. Temps warm through the 50s through the
end of the week, with some southern spots getting to near 60
degrees by Saturday.
A cold front then slowly approaches from the north Saturday
night. The front looks to be weakening and slowing upon
approach, so the exact timing of the frontal passage and extent
of the cool down remains somewhat uncertain at this time.
Regardless, some showers accompany the front either Saturday
night or Sunday, especially across northern areas. A ridge
starts to build into the Northeast by early next week, so there
is some uncertainty on whether or not the front fully manages to
clear the area, so this will be an item of interest to watch
over the coming days.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Short Term...KHIE is likely to hang onto lowered ceilings into
tonight with VCSH. Most of the rest of the region will have IFR
and LIFR conditions this evening, before slowly becoming VFR
during the overnight hours. Winds turning around to the
northwest this evening will become somewhat gusty overnight, to
around 20 kts or so. VFR prevails at all terminals Tuesday into
Tuesday night with diminishing NW flow.
Long Term...Some scattered rain and snow showers may bring
occasional restrictions at times on Wednesday, but otherwise VFR
conditions prevail from Wednesday through Saturday. Some
showers are then possible again Saturday night into Sunday
&&
.MARINE...
Short Term...Winds are forecast to gust up to around 25 kts
over the outer waters tonight, before diminishing on Tuesday as
high pressure builds into the region. Low pressure will move
well off the Mid Atlantic coastline Tuesday night.
Long Term...Low pressure passes east of the Gulf of Maine on
Wednesday, with gusty northwest winds likely bringing SCA
conditions behind the system Wednesday night. High pressure then
builds across the waters from the southwest on Thursday and
persists into the weekend. Increasing southwesterly winds may
gust to 25kts at times late this week. A cold front then
approaches from the north Saturday night.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 11 AM EDT Tuesday for ANZ150-152-
154.
&&
$$
NEAR TERM...Cannon/Cornwell
SHORT TERM...Cannon
LONG TERM...Clair
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
907 PM CDT Mon Oct 30 2023
.SYNOPSIS...
Issued at 902 PM CDT Mon Oct 30 2023
After a dry but cool day Monday, Tuesday will feature a chance for
snow, along with gusty northwest winds which will bring wind chills
into the teens by late evening. Wednesday morning low temperatures
are expected to be in the upper teens to low 20s, but temperatures
will gradually moderate towards normal to close the work week.
&&
.UPDATE...
Issued at 906 PM CDT Mon Oct 30 2023
A surface high pressure ridge axis has built over central IL this
evening, providing the lightest winds in the past several days,
along with mostly clear skies. Temperatures range from the upper
20s to mid 30s, on track for lows in the mid 20s across the area,
which will be the first hard freeze of the year in southeast and
east-central IL, and a freeze warning remains in effect
overnight. The only update needed this evening is to trim cloud
cover slightly given the efficient clearing seen on satellite.
37
&&
.DISCUSSION...
Issued at 314 PM CDT Mon Oct 30 2023
------------------------- [Key Messages] -------------------------
1. High confidence (> 90% chance) in sub-freezing temps area wide
tonight. About a 70% chance for a hard freeze tonight,
especially east of the IL River.
2. 20-40% chance for accumulating snow tomorrow late morning
through the afternoon. Highest chances for accumulation are
north of I-74. These scattered snow showers could be briefly
heavy and produce gusty winds.
3. Even outside of snow showers, northwest winds will be gusting
30-35 mph tomorrow afternoon.
4. Wind chills in the upper teens to low 20s during the evening
Tuesday. Trick-or-treaters will need to bundle up. Low
temperatures Wednesday morning could dip into the teens in
low-lying areas.
-------------------------- [Discussion] --------------------------
Unseasonably cool weather continues across central Illinois this
afternoon, with temperatures in the upper 30s to low 40s in most
spots at 3pm. With northwest breezes, wind chills are holding in the
low 30s. For reference, normal high temperatures this time of year
are around 60 and lows around 38.
Tomorrow will be even colder, as 850mb temperatures drop to -10 to -
12 degC beneath a compact shortwave which will drive a cold front
through our area during the morning west of I-57 and early afternoon
east. The CAMs continue to disagree (both run-to-run and model-to-
model) in the southward extent of a band of snow (perhaps mixed with
rain south of I-72) accompanying that front. The 30.06z run of the
HRRR had this line crossing pretty much the entire CWA, while the
30.12z iteration doesn`t really bring it south of I-74 at all. The
30.12z NAMNest, by comparison, impacts all except a couple of our
farthest southeast counties. With this band of snow, a brief drop in
visibilities along with gusty winds will be possible, though winds
aloft really increase during the afternoon as (1) the mixed layer
deepens and low level lapse rates steepen and (2) the HREF
ensemble mean brings northwest 850mb winds to around 40 kt north
of a Galesburg to Robinson line. NBM guidance is suggesting
probabilities for SBCAPE > 25 J/kg at around 40-65% (highest in
our northeast counties) for late morning-mid afternoon tomorrow,
when, despite surface temperatures being in the mid to upper 30s,
snow should be the predominant p-type given wet bulb temperatures
(per the 30.12z NAM) should be between 0 and -1 degC across most
of the area. We won`t have the frontal forcing during the
afternoon, but the HRRR continues to advertise some of these
splotches of snow will be heavy, and given the strong winds aloft,
which outside of convective snow showers will already be gusting
30-35 mph, they will likely also tap into some of those stronger
winds aloft for momentum transport to the surface. HREF ensemble
max advertises pockets of gusts over 40 mph, and this is likely
driven the models` attempts at resolving those stronger bursts of
convectively-enhanced, mixing- induced surface gusts. If snow
falls fast enough, it`s certainly possible it would overcome the
warm ground and result in some accumulations. NBM and HREF both
have sub 10% probabilities area- wide for more than an inch of
snow, but have 25-40% or greater chances for a tenth of an inch -
enough to turn the tips of the grass white - along the I-74
corridor. Still, with the strong dynamics associated with this
system, it seems like there`s potential for it to overperform and
one should not be surprised to find a quick inch of snow
accumulation. It may ultimately come down to close and careful
monitoring of surface observation trends tomorrow morning to
evaluate whether an SPS could be necessary for a low-end snow
squall with the front...or even for those briefly intense and
gusty isolated afternoon snow showers.
One thing is for sure, it`s going to be a cold trick-or-treat for
the little ones who will need to really bundle up to stay warm
and prevent frost-bite. Wind chills will drop through the 20s and
into the teens during the evening, and, depending on how quickly
winds ease up tomorrow night, low temperatures could plummet into
the teens in low-lying areas. NBM has pockets of 50-70%
probabilities for low temperatures less than 20 degF Wednesday
morning near the IL River.
As this compact system exits our area quickly to the east on
Wednesday, temperatures will moderate slowly towards normal by the
end of the work week. Model discrepancies become apparent as early
as the weekend in small to medium scale details, but WPC`s clusters
look fairly similar to one another with the general trend being
towards zonal or WNW 500mb flow across the Midwest and Great Lakes
regions, with near to slightly above normal h5s.
Bumgardner
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 642 PM CDT Mon Oct 30 2023
A strong shortwave and trailing cold front will move through the
region from around 12Z-16Z Tuesday morning, bringing snow showers
and gusty winds. Several models depict a fairly intense band of
snow sweeping through portions of northern IL, although
disagreements in the southward extent of the band and exact timing
continue. Likelihood is highest along the I-74 corridor and
northward. Have opted to highlight the most likely timeframe with
a tempo group for IFR cigs/MVFR vsbys and wind gusts approaching
30 kts for the I-74 terminals, and for KDEC only MVFR conditions.
However, adjustments to timing and intensity may be needed in
later TAFs. With the upper level trough remaining over the area
through the afternoon, at least scattered snow flurries will be
possible through 00Z. Winds Initially W around 4-8 kts, then
increasing out of the SW to around 12 kts by 11Z-13Z, and shifting
to WNW and increasing to 16-22 kts with gusts to near 30 kts by
15Z-17Z.
37
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 9 AM CDT Tuesday for ILZ044>046-052>057-
061>063-066>068-071>073.
&&
$$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1104 PM CDT Mon Oct 30 2023
.DISCUSSION...(This evening through Monday)
Issued at 238 PM CDT Mon Oct 30 2023
KEY MESSAGES:
- A potent system will pass through tonight, bringing widespread snow
showers and gusty winds. Accumulations of 1 to 2 inches expected
across central/eastern MN and WI. Some patchy blowing snow is
possible early Tuesday.
- Cold air remains in place through midweek. Slight warming into the
40s by late week, along with with the next chance for precipitation.
Satellite imagery reveals an impressive upper wave now descending
into North Dakota. This feature will continue to dig and become more
negatively tilted as it heads across central MN and southwest WI
tonight. Areas of snow showers are pinwheeling around the upper low
and visibilities are being reduced to 3/4 to 1/2 mile in some
instances over northeast ND, indicating some brief intense
bursts/snow squalls. The snow showers will build southeast for the
rest of the afternoon and should reach central MN early this evening
(7-8 PM), then western WI around 8-10 PM. Since these are pockets of
snow showers, continuous snow is not expected but a few areas may
have more prolonged periods which will help add up their totals.
Periods of snow will continue through early Tuesday morning before
the low pulls away to the southeast. Total accumulations of 1 to 2
inches are expected, but since this is more convective and less
continuous, amounts could vary within short distances.
With this system will also come strong cold air advection and gusty
winds. With the strong cold air advection will naturally come steep
low level lapse rates. Forecast soundings indicate 40-45 kt winds at
the top of the boundary layer and could see some gusts as high as
about 40 kts across western and southern MN overnight. Since the bulk
of the snow will be northeast of this area, planning to issue a Wind
Advisory. Gusty winds are also possible within the area of greatest
accumulation, but shouldn`t be as strong as to the southwest.
Nonetheless, some patchy blowing snow is possible - particularly in
the areas that can receive a couple inches. The wind will ease after
mid morning Tuesday and conditions should improve shortly thereafter.
Northwest upper flow will prevail into late week but southerly low
level flow will help moderate temperatures back into the 40s by
late week. The pattern will flatten more this weekend into next week
with several disturbances tracking east across the northern CONUS.
Low chances for precipitation are maintained this period, with low
confidence on the details or timing of each.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1050 PM CDT Mon Oct 30 2023
IR satellite imagery across central MN shows cooling cloud tops as
the 2nd round of snow is getting going. Round one will slow down over
western WI and there won`t be a break in the snow for RNH/EAU between
this initial burst of snow on the cold front and the developing
deformation band. It`s taken 24 hours, but the HRRR finally looks to
have realized there will be a deformation band and the 2z run looks
to be a good general idea for how this deformation band will evolve.
Looking up over northern MN and NoDak, clouds improve pretty quick
once it stops snow, so current TAFs may be leaning pessimistic with
how long it takes for VFR conditions to return. For winds, they`re
jumping as we get behind the front, but they still look to start
settling down slowly through the morning.
KMSP...Still looks good for a second wave of snow to arrive between
7z and 8z. The one trend we`ve seen with recent model runs is the
potential for another burst of heavier snow (1sm vis) around 12/13z,
so we`ll have to keep an eye on that.
/OUTLOOK FOR KMSP/
Wed...VFR. Wind SW 10-15 kts.
Thu...VFR. Winds W 5-10 kts.
Fri...VFR. Wind SE 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Wind Advisory until 10 AM CDT Tuesday for Chippewa-Lac Qui Parle-
Redwood-Renville-Stevens-Swift-Yellow Medicine.
Wind Advisory until 10 AM CDT Tuesday for Blue Earth-Brown-
Faribault-Freeborn-Martin-Nicollet-Waseca-Watonwan.
WI...None.
&&
$$
DISCUSSION...Borghoff
AVIATION...MPG
Area Forecast Discussion
National Weather Service Phoenix AZ
452 PM MST Mon Oct 30 2023
.UPDATE...Updated 00z Aviation Discussion...
&&
.SYNOPSIS...
Cool high pressure will moderate the next several days as near to
below normal temperatures steadily warm into an above normal
category. Occasionally breezy conditions will be common through the
midweek period across south-central Arizona. Otherwise, chances of
rain area essentially zero through at least early next week.
&&
.DISCUSSION...
Latest surface analysis reveals an anomalous surface high across
the southern Rockies, with a cold air mass plunging southward into
Texas. Further west across the Desert Southwest, conditions are
not quite as chilly, however cool and dry conditions predominate
with afternoon temperatures generally in the upper 70s and lower
80s across the lower deserts. Morning ACARS soundings measured
PWATs near a quarter of an inch, while at the surface, dewpoints
in the teens and twenties are prevalent.
RAP streamline analysis indicates a pronounced northwesterly flow
in the upper levels. A weak short wave trough is also evident on
water vapor imagery east of the Four Corners, which brought a
reinforcing shot of cool air to the region this morning and
produced wind gusts up to 35 mph, particularly across the
foothills east of Phoenix. Winds earlier this morning were also
strong enough to generate areas of blowing dust across portions of
Pinal County, which briefly resulted in reduced visibilities near
the intersection of I-8 and I-10.
Latest HREF indicates winds will subside this afternoon, however
ECMWF EFIs above 70 percent suggest another period of windy
conditions is likely tonight and Tuesday morning as another
surface high drops southward into the Plains. The strongest winds
are again expected in the same spots east of Phoenix, mainly in
the foothills and along ridge tops in the Superstitions. HREF
median/mean gusts were considerably stronger than what was
observed this morning. Nevertheless, even the 25th percentile
suggests occasional breeziness across the Valley tomorrow.
Some of the coldest temperatures of the fall are expected
overnight in the sheltered areas outside of Phoenix where light
winds and radiational cooling can be maintained. There is a 60
percent chance temperatures will drop into the 40s near Deer
Valley and portions of the West Valley. At Sky Harbor Airport, the
NBM forecast low temperature is 55 degrees, which would make it
the coolest temperature observed since early April.
Model ensembles are in good agreement and indicate the ridge
across the western CONUS will persist through at least early next
week, initially oriented meridionally across the Great Basin
before shifting into the eastern Pacific and extending eastward
with a zonal ridge axis. Positive height anomalies are expected to
increase, which will translate into a gradual warming trend and a
return to above normal temperatures by the middle of the week.
Model clusters are also exhibiting little variability and with
PWATs likely remaining below normal, the pattern will remain
unfavorable for any precipitation across the Desert Southwest.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Easterly winds will prevail throughout the period. Light winds aob
10 kts expected through early Tuesday morning. Winds will pick up
during the mid to late morning hours with occasional gusts as
high as 20-25 kts before subsiding to aob 10 kts by the mid to
late afternoon hours. Skies will remain mostly clear.
Southeast California/Southwest Arizona including KIPL and KBLH:
At KIPL, winds will fluctuate between the northwest and north with
speeds aob 10 kts. At KBLH, winds will favor a northerly component
with moderate speeds through this evening fluctuating between
10-15 kts before becoming light aob 8 kts through the rest of the
period. Skies will remain mostly clear.
&&
.FIRE WEATHER...
Very dry conditions with no chance of rain will continue through the
week as temperatures gradually warm back above the seasonal normal.
Minimum afternoon humidity levels will generally fall into the teens
with somewhat higher values over mountain areas of eastern
districts. Overnight recovery will only be poor to fair in a 15-40%
range. Wind speeds will remain somewhat enhanced into the middle of
the week favoring an east or north component before weakening
substantially later in the week. Ridge tops and terrain gaps of
eastern districts should experience the strongest gusts above 20 mph
creating periods of elevated fire danger.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
AVIATION...Lojero
FIRE WEATHER...Young/18