Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/09/19
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
313 PM MDT Tue Oct 8 2019
.SYNOPSIS...
Two upper level disturbances moving through the region will help
force scattered showers and thunderstorms for the remainder of the
afternoon and evening. A few stronger storms may produce hail and
gusty winds. Most of this activity will push east of the area
by midnight. Drier and warmer conditions will prevail Wednesday
and Thursday, but a strong cold front will bring another taste of
Fall to the region by Friday morning. High temperatures will be in
the 60s across the lowlands Friday, with low temperatures in the
30s and 40s over much of the area Friday night. A slow warming
trend is expected heading into early next week.
&&
.DISCUSSION...
Water vapor imagery and RAP analysis shows a weakening low
amplitude upper-level trough over Arizona heading east, and a
leading shortwave trough over New Mexico. The initial trough
helped force a cluster of showers and thunderstorms which now runs
roughly from Alamogordo to Las Cruces. This first batch of storms
was perhaps a little more intense than most of the CAMS runs from
this morning suggested. Most of those model runs indicated
thunderstorms associated with the second trough would be more
intense, and would make a run at the Las Cruces/El Paso areas
between 23Z and 01Z. However, there is now some added uncertainty
thrown into the mix as the cold pool from the earlier storms may
have stabilized the lower levels over much of Luna and Dona Ana
Counties. Outflow from these storms has weakened as it has pushed
into Santa Teresa and the lower Mesilla Valley, but a few showers
are trying to develop east of the Franklin Mountains. So far,
storms developing over Hidalgo County associated with the 2nd
disturbance have been struggling, and lagging behind what the
recent HRRR (and earlier CAMS) runs suggest.
Overall, will still keep the risk of storms this evening, but
southern portions of Dona Ana County and areas east of the Rio
Grande may now be more favored for stronger storms with the
potential for marginally-severe hail and wind gusts.
Pretty much all of this activity will push east of the area
shortly after 06Z. Drier westerly flow will prevail tomorrow and
Thursday as an upper low embedded in a high amplitude upper trough
moves across the northern Rockies. Colder air flowing in behind
this system will drop down the Plains. We`ll get a glancing blow
Thursday night and Friday with a side-door front pushing through.
We`ll likely see the coolest temperatures of the season Friday and
Friday night, with highs stuck in the 60s, and freezing
temperatures possible in part of the Sacramento Mountains and Gila
Region. Some lowland sites could drop into the mid or upper-30s
by early Saturday morning. NBM and Superblend temps still running
rather high compared to GFS (MEX) and EC MOS guidance, so went
with the cooler temps for Fri/Sat.
Dry conditions look to prevail through the weekend. The GFS had
been teasing the idea of a East Pacific tropical system bringing
moisture to our area early next week, but most of the ensemble
members were not on board with the solution, and neither is the
12Z deterministic GFS, though it does hint at some subtropical
moisture sneaking in ahead of a trough mid-week (beyond the
forecast period).
&&
.AVIATION...Valid 09/00Z-10/00Z...
Mostly VFR conditions continue, but periods of MVFR and IFR are
possible near thunderstorms through 3Z, then VFR prevails across the
region after 12Z. Some storms will be capable of producing hail and
downburst winds. Outflow boundaries to 45 kts are possible during
the evening hours too. Southerly winds will continue through 12Z
with speeds to 10 to 15 kts, then veering to the west, and speeds
increasing after 18Z to 15 to 20 kts with stronger gusts over area
mountains as a broader upper trough approaches the area.
&&
.FIRE WEATHER...
The upper trough currently in the area will move on overnight,
but it will be quickly replaced by a broader upper trough
tomorrow. Showers and thunderstorms will continue through the
night with some of the storms producing hail and strong winds
through the early evening hours. As the next trough moves in we
will start drying out with minimum relative humidity going down to
around 20 percent in most areas. The northern zones will drop to
the teens over the weekend as more drier air streams in behind a
cold front. Ventilation rates will be excellent the next two days
as we get higher transport winds. The cold front on Friday is
expected to bring cooler temperatures and breezy winds on Friday.
Afterwards westerly winds prevail bringing relatively dry and warm
air and a chance of some moisture early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 64 88 63 86 / 40 0 0 0
Sierra Blanca 60 86 60 86 / 40 0 0 0
Las Cruces 57 85 54 80 / 30 0 0 0
Alamogordo 58 84 56 81 / 50 0 0 0
Cloudcroft 46 62 46 59 / 50 0 0 0
Truth or Consequences 56 83 54 80 / 10 0 0 0
Silver City 52 75 48 71 / 10 0 0 0
Deming 55 84 51 81 / 20 0 0 0
Lordsburg 55 85 53 81 / 0 0 0 0
West El Paso Metro 63 87 62 85 / 40 0 0 0
Dell City 60 87 60 87 / 50 0 0 0
Fort Hancock 64 90 63 90 / 30 0 0 0
Loma Linda 60 82 59 81 / 50 0 0 0
Fabens 64 88 63 88 / 40 0 0 0
Santa Teresa 60 86 60 84 / 40 0 0 0
White Sands HQ 61 84 59 81 / 40 0 0 0
Jornada Range 56 83 53 80 / 40 0 0 0
Hatch 56 84 54 80 / 30 0 0 0
Columbus 58 86 54 83 / 20 0 0 0
Orogrande 58 84 58 82 / 40 0 0 0
Mayhill 51 73 50 69 / 50 0 0 0
Mescalero 51 71 50 66 / 50 0 0 0
Timberon 50 70 50 67 / 50 0 0 0
Winston 45 76 44 73 / 10 0 0 0
Hillsboro 53 81 50 76 / 20 0 0 0
Spaceport 55 83 53 79 / 30 0 0 0
Lake Roberts 45 75 42 69 / 10 0 0 0
Hurley 51 78 48 74 / 20 0 0 0
Cliff 49 82 46 77 / 0 0 0 0
Mule Creek 51 79 49 74 / 0 0 0 0
Faywood 52 79 48 75 / 20 0 0 0
Animas 56 86 53 83 / 0 0 0 0
Hachita 55 84 53 81 / 10 0 0 0
Antelope Wells 56 84 54 82 / 10 0 0 0
Cloverdale 56 81 52 78 / 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
25-Hardiman / 29-Crespo-san
Area Forecast Discussion
National Weather Service Hastings NE
703 PM CDT Tue Oct 8 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 338 PM CDT Tue Oct 8 2019
Aloft: Aircraft winds and animations of RAP tropopause analyses
indicated low-amplitude zonal flow over the Cntrl/Wrn CONUS. A
small shrtwv trof was over the NEB Panhandle and CO and was moving
E. This trof will cross NEB/KS tonight with nothing more than
some high clds. The bigger story is the deep trof sinking into the
Pac NW from SW Canada. 500 mb heights fell as much as 160 m over
WA from 00Z- 12Z. The longwave flow will amplify tonight and
tomorrow as heights cont to fall with the SW Can trof dropping
into the Nrn/Cntrl Rckys.
Surface: 1027 mb high pres was over the Ern GtLks. An
unseasonably strong cold front extended from Cntrl Canada SW into
the Pac NW. The high will strengthen as it heads into Ern Canada
thru tomorrow. Meanwhile...a very cold air mass and its cold front
will cont to spread S and E. By 00Z/Thu...the front is fcst to
extend from MN thru the NEB Sandhills thru Nrn CO...with a strong
1034 mb high over MT.
Rest of this afternoon: Sunny...breezy and seasonably warm. Temps
will are peaking right about now.
Tonight: Mostly clr to partly cldy as some patches of
cirrostratus move thru with the shrtwv trof. A mild night. Temps
10F above normal.
Maintained a low (20%) POP for isolated shwrs/tstms toward dawn
over the far SE fringe of the CWA...associated with WAA and modest
low- lvl mstr return.
Wed: Possibly a leftover shwr/tstm during the AM far SE fringe.
Otherwise mostly sunny...but turning partly cldy. Still seasonably
warm and breezy.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 338 PM CDT Tue Oct 8 2019
Aloft: The deep trof over the Nrn/Cntrl Rckys at 00Z/Thu will
slowly progress E Thu with a low dvlpg over WY. This low will
cross NW NEB Thu night on its way into MN where it will stall over
MN Fri-Sat due to a downstream block over the NW Atlc. The low is
then fcst to creep NE into ON Sun-Mon. In its wake...cyclonic NW
flow will remain over NEB/KS thru Sat. By Sun its effects on the
rgn should decrease as deamplification occurs. Global mdls cont to
indicate a wk shrtwv trof will be migrating thru the Wrn USA.
This trof should cross NEB/KS Mon...with more cyclonic WNW flow in
it wake Tue.
Surface: Lee cyclogenesis will commence Thu eve over CO. This low
will eject into KS by 12Z/Thu. This low will move N along the
front as it crosses the CWA Thu while 1036 mb high pres over the
Rckys begins building in. The low will move into MN Thu night and
stall thru Sat night as it occludes. The circulation around the
low should finally release its influence on NEB/KS Sat. A wk low
is fcst to form over CO Mon and head E acrs KS. Anticyclogenesis
is then fcst Tue with strengthening high pres emerging from the
Nrn Rckys onto the Plns.
Temps: Very mild for most of Wed night ahead of the front...but
temps will plunge after the front moves thru. That will cont into
Thu AM with temps holding steady 35-45F in the afternoon.
Continued much colder than normal Fri with highs 25-30F below
normal. Back into the 50s Sat-Tue...with low-mid 60s SW fringe.
Cold: It will only take 1 night of this kind of cold to end the
growing season...but 2 hard freezes will occur back-to-back Fri
and Sat mornings over most of the CWA (28F or colder). It is
likely that Ord and Greeley will see freezes 4 if not 5
consecutive nights/mornings per the last svrl runs of MEX MOS.
It`s now in our official fcst.
Wind Chills: Anyone outdoors Fri AM will need winter wx gear.
WCI`s will range from the low teens to low 20s with howling NW
winds.
Winds: NW 20-35 mph Thu-Fri...gusting 40-50 mph in strong CAA
with downward transfer from 4K ft. GFS mixing heights and winds
are higher/stronger than the NAM.
Refreshed and resent the SPS at 1943Z highlighting cold/wind
chills/winds.
Precip: With the upr low remaining NW of the CWA...we will be
dealing with the dry slot. Therefore...decided to place more of
an emphasis on patchy drzl Wed night into Thu...which could turn
to frzg drzl Thu night. Precip will struggle to form over the CWA
with this system. Can`t completely rule out some shwrs and sub-
svr tstms...but it`s not looking good. The low-lvl mstr will
create conditional instability...but will shwrs and tstms actually
dvlp? The mstr will be shallow. Given that...it`s psbl even the
meager mention of snow that we have in the fcst may be overdone.
Based on past experience and mdl RH cross sections...when precip
occurs Thu night it could be patchy frzg drzl psbly mixing with or
briefly changing to very light snow (snow grains) at times when
slightly deeper mstr bands move thru. Believe the shallow NAM RH
is probably more realistic vs GFS. Some leftover snow flurries may
linger in a few spots Fri.
Overall...precip amts will be very minor with this system.
Dry wx currently expected Sat thru next Tue.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 645 PM CDT Tue Oct 8 2019
Strong low level wind shear will be the primary aviation concern
tonight with a strong low level jet of 40-45 kts. VFR conditions
are expected through Wednesday morning and then we could start to
see MVFR ceilings working into some areas Wednesday afternoon,
primarily around KGRI and points east from there. It will be
breezy throughout the forecast period with the wind remaining
southerly to south southeasterly.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Jacksonville FL
929 PM EDT Tue Oct 8 2019
.UPDATE...
Cold front will stall just south of the area tonight with surge
of Ne winds behind it. The shower activity across the far south
has just about dissipated. There are lingering showers offshore.
High- res HRRR indicating a resurgence of showers by later tonight
across the far Se counties in closer proximity to front. Also
potential for low clouds later tonight lingering into Wed given
moist low level Ne flow coupled with dry mid level air.
&&
.AVIATION...
[Through 00Z Thursday]
Potential continues for low clouds to develop later tonight and
have prevailing IFR at VQQ and GNV aft 07Z-08Z. Have prevailing
MVFR at remaining TAF sites aft 08Z-09Z. Gusty Ne winds expected
for Wed with prevailing MVFR.
&&
.PREV DISCUSSION [406 PM EDT]...
.NEAR TERM [Tonight and Wednesday]...Shower activity will continue
this evening over ne Fl with a slow decrease in coverage overnight.
A cold front will push through the region overnight with low clouds
expected to develop across the area in its wake before daybreak.
Drier air from the north will spread south with showers mostly
confined to areas south of a St. Augustine to Gainesville line on
Wednesday.
.SHORT TERM [Wednesday night Through Friday Night]...Drier air will
spread further across the area from the north as high pressure
builds in at surface and aloft. Rain chances will persist near the
ne Fl coast Wednesday night through Thursday night as onshore
flow persists. Onshore winds will gradually weaken by Friday along
with shower activity.
.LONG TERM [Saturday Through Tuesday]...High pressure will weaken and
shift east of the area on Saturday. A cold front will weaken as
it approaches the area from the northwest as energy aloft remains
well to the north. The front will stall near the FL/GA line Sunday
into Monday with dry conditions through the period and temperatures
above average levels.
.MARINE...
Northeast winds will continue through Friday mostly in 15 to 20
knots range as high pressure builds in from the north. Seas will
remain also remain elevated with advisory conditions to continue
offshore through Wednesday evening. Slowly subsiding conditions
expected over the weekend as high pressure weakens and settles
over the area. A weakening cold front will approach the waters on
Sunday.
Rip Currents/Surf: Wind waves from Northeast flow and swells will
continue to support a high risk of rips. Rough surf will continue
with breakers in the 3-6 ft range.
Coastal Flood: Trapped water in the St Johns River Basin will
continue to produce Action/Elevated type levels during the high
tide cycle through the week. A moderate surge of NE winds on
Wednesday combined with localized runoff into the Basin may push
water levels to slightly higher values by the evening high tide
cycle on Wednesday with more widespread minor flooding possible
and Coastal Flood Advisories may need to be posted. These
conditions may continue for Thu/Fri in the St Johns River Basin
with the approach of the full moon phase this weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 65 84 62 84 58 / 10 0 0 0 0
SSI 71 80 71 80 68 / 10 0 10 20 0
JAX 70 83 68 83 65 / 20 10 10 20 10
SGJ 73 80 71 81 68 / 30 60 30 30 10
GNV 69 83 67 84 63 / 20 30 10 10 0
OCF 70 85 68 86 65 / 30 70 20 20 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 5 AM EDT Wednesday for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
GA...High Rip Current Risk until 5 AM EDT Wednesday for Coastal
Camden-Coastal Glynn.
AM...Small Craft Advisory until 9 PM EDT Wednesday for Waters from
Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM-
Waters from Fernandina Beach to St. Augustine FL from 20 to
60 NM-Waters from St. Augustine to Flagler Beach FL from 20
to 60 NM.
&&
Area Forecast Discussion
National Weather Service Key West FL
1041 PM EDT Tue Oct 8 2019
.DISCUSSION...
The 00z KEY evening sounding observed an extremely moist
Precipitable Water (PW) value of 2.34", nearly tying a record high
for this day of the year in the sounding climatology. MIMIC PW
imagery shows the axis of very moist air extending from the
northern Yucatan Peninsula through the Straits and up to the
northern Bahamas. This moisture axis exists on the equatorward
side of a 300 mb jet streak that stretches from the central Gulf
to the Mid-Atlantic region and beyond.
The jet streak will exit northeast over the next 24 hours,
eliminating the large-scale focus for the moist axis and the
remaining synoptic lift over the forecast area. Rain chances will
be on a steady downward trend through this weekend as the moist
axis breaks apart and eventually gets shoved away and replaced
with drier air spreading in from the northeast this weekend.
In the near term through Wed morning, radar currently shows a few
areas of stratiform rain producing light rain, especially over the
Straits. Most of the light rain is in the process of shrinking and
weakening.
Then late tonight to near sunrise on Wed morning, mesoscale models
including the 01z HRRR and the 00z ARW blossom new convection over
the Straits and near the Lower Keys, lifting showers and
thunderstorms out to the north into the Gulf waters later in the
morning and into the afternoon.
&&
.MARINE...
A trough of low pressure draped from the extreme Southeast Gulf
of Mexico into extreme South Florida will remain nearly stationary
overnight. This trough is expected to dissipate as it settles
back down to near the Keys Wednesday through Thursday. Thereafter,
the southern periphery of a strong high pressure system along the
Eastern Seaboard will expand down the Sunshine State.
&&
.AVIATION...
VFR conditions are expected to prevail at both Key West and Marathon
terminals. The radar is showing generally stratiform rain showers
across the Florida Straits, and they are expected to weaken over the
next few hours. Isolated to scattered showers with possible embedded
thunderstorms are possible tomorrow morning, resulting in brief
periods of sub VFR conditions. Winds are expected to remain light
and variable through the forecast period.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory for FLZ076.
GM...None.
&&
$$
Public/Marine/Fire...Haner
Aviation/Nowcasts....SDR
Data Collection......NB
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Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
945 PM CDT Tue Oct 8 2019
.UPDATE...
Locally dense fog will be the primary overnight weather concern.
Stubborn area of low clouds persisted over northeast MS this
evening, but was gradually clearing on the north side. This
newly-cleared area, and portions of west TN to the north, remain
at greatest risk for locally dense fog formation overnight.
Will closely monitor trends for a possible Dense Fog Advisory.
PWB
&&
.PREV DISCUSSION... /issued 625 PM CDT Tue Oct 8 2019/
DISCUSSION... /issued 308 PM CDT Tue Oct 8 2019/
A stubborn stratus deck has persisted across northeast MS today,
blemishing what is an otherwise fantastic early October day across
the Mid-South. Temperatures remain in the 60s where the cloud
cover has lingered, warming into the 70s elsewhere. The shortwave
trough that brought yesterday`s cold front to the region is moving
east. Another cool night is on tap across the Mid- South. Much of
west TN and the Bootheel will dip into the 40s again tonight with
lower 50s anticipated farther south. Winds will be light and may
promote patchy fog across the area, mainly east of the MS River.
A shortwave trough will traverse the Ozarks on tomorrow, but scant
moisture will keep the CWA precipitation free. Temperatures will
moderate as southerly flow resumes and mid-level heights build.
The warm advection pattern will continue Wednesday night into
Thursday, drawing Gulf moisture poleward and increasing Mid-South
dewpoints back into the 60s. The global models all indicate some
warm advection showers developing east of the MS River Thursday
morning. Some mid-level capping will limit the vertical extent and
preclude thunder. Rain chances were limited to 20% given the high
spatiotemporal uncertainty.
A deep trough over the western CONUS will move slowly east into
the Plains on Thursday. This trough is progged to eventually
lift northeast into the western Great Lakes on Friday but will
drive a relatively strong cold front across the region. The timing
of the front will greatly influence Friday`s max temperatures.
This front is expected to arrive during the day Friday, providing
a good chance for showers and thunderstorms. Rain chances will
increase beginning late Thursday night, spreading across the area
through Friday, then tapering off from west to east by Saturday
morning.
The medium range models continue to suggest a region of surface
based instability nosing up the frontal boundary on Friday in
than environment with deep-layer shear ~30 kts. Given the line-
normal shear vectors, storms are likely to take on a linear mode
which could lead to a damaging wind potential.
Cooler and drier air will settle over the Mid-South this weekend.
While rain chances may linger into Saturday morning, most of the
area will be dry throughout the weekend with below normal
temperatures. Highs on Saturday are projected to be in the lower
60s with overnight lows in the upper 30s and lower 40s. We`re
still keeping an eye on the potential for a light frost across
portions of the Mid-South Sunday morning.
The pattern becomes more quasi-zonal by early next week as the
late week trough lifts north over Ontario and a second wave moves
across the northern Rockies. Both the deterministic GFS and ECMWF
are also lifting the remnants of a Pacific tropical cyclone over
northern Mexico and across TX early next week. Deeper moisture
will interact with weak perturbations in the flow aloft to
promote increasing rain chances late Monday into Tuesday. Expect
temperatures Sunday-Tuesday to remain near climatological norms.
MJ
&&
.AVIATION...
00Z TAF Set
Stratus clouds continue to hang on at KTUP, but should be gone by
another hour or so. Then, expect VFR conditions which will be
short-lived as fog will begin to develop by 05-07Z, and will
likely become dense near KTUP. Expect fog and/or low stratus to
develop over much of West Tennessee and Northeast Mississippi. The
HRRR is then showing the fog advecting into KMEM around 12Z due
to the easterly flow. For now have added 3SM BR BKN005 line at 11Z
at KMEM through 15Z. If fog and low stratus do advect in,
conditions could be lower. Some stratus could impact KJBR briefly
around 14-15Z, but for now have left mention of it out. Fog will
dissipate and stratus will scatter out by 15-17Z. VFR conditions
will then occur through the rest of the TAF period. Winds will be
light and variable overnight becoming southeasterly tomorrow.
Speeds will remain light.
KRM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
823 PM EDT Tue Oct 8 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 400 PM EDT TUE OCT 8 2019
WV imagery and RAP analysis indicated a mid/upper level trough into
the northwest CONUS and a ridge through the the central Great Lakes
resulting in wsw flow toward Upper Michigan. At the surface,
strengthening southerly flow prevailed through the Upper Mississippi
Valley into the northern Great Lakes between a trough from northern
Manitoba to southeast Montana and a high pressure over the eastern
Great Lakes. Vis loop showed patchy high clouds into Upper Michigan
and some more mid clouds moving into nw WI in the WAA pattern.
Tonight, expect the gusty south winds too diminish this evening over
most area. However, downslope flow should maintain winds gusting to
20-25 mph near Lake Superior. Boundary layer mixing will also keep
temps from falling off as far with min readings from the mid 40s
inland to the lower 50s along the Great Lakes.
Wednesday, dry air will continue to dominate the area. With plenty of sunshine,
daytime mixing to near 3k ft will support max temps into the
upper 60s and wind gusts of 20-30 mph.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 554 PM EDT TUE OCT 8 2019
As the much anticipated major storm system begins taking shape over
the northern Rockies Wednesday night, quiet weather will continue
locally through the day Thursday. However, clouds will be streaming
in as deeper moisture advects northward and the jet rounding the
closed upper low lifts into the Upper Midwest. Some rain may move
into the far west late in the afternoon, but for the majority of us,
rain will hold off until after dark Thursday evening when more
substantial theta-e advection and Q-vector focring overspread the
region. This will initially be a light steady rain that continues
into Friday morning, but that changes in the afternoon and evening
as the system`s cold front rushes through. Models don`t indicate any
instability for thunderstorms (NAM has maybe 300 J/kg MUCAPE at most
over the west), but strong fgen forcing in a region of 1.25-1.5"
PWATs should still lead to heavy showers with the FROPA late Friday.
That said, the front will be a quick-mover so overall rainfall
totals won`t be that high - an inch at most and closer to half an
inch for most of the U.P. Winds will be pretty breezy on Friday as
well, with 25-35 mph gusts initially out of the SE ahead of front
quickly becoming SW behind the front but continuing to gust to 30
mph or more. SE gales look probable on eastern Lake Superior as well.
Models are in good agreement that the low pressure area occludes
over northern Minnesota Friday night and then very slowly drifts
eastward across Lake Superior throughout the weekend. With plenty of
remnant moisture and cold mid-levels, there will be rain and snow
showers around for much of the weekend. It`s not actually lake-
effect as the surface flow remains SW through Sunday, but rather
enough wrap-around moisture, reduced stability, and "dirty" cyclonic
flow aloft with numerous vort packets rotating about the upper low.
Boundary layer temps stay pretty marginal for any snow accumulation
with model progged surface wet bulb temps at or above freezing.
Still, it`s not impossible that a little bit of slush accumulates
over the higher terrain, especially Saturday night.
There could also be a rare instance of October Lake Michigan lake-
effect precip (read: rain) Saturday afternoon into Sunday morning.
Nearshore water temps are still around 10-11 C in GLERL analysis
today so even with a bit of cooling from mixing this week, 850 mb
temps around -5 to -6 C would provide enough lake-based instability.
At the moment, SSW wind would favor a band pointing into the far
eastern U.P. east of our CWA, with perhaps a weaker band off of the
Bay of Green Bay. GFS wet blub zero heights of 1000-2000 ft would
keep this precip predominantly (if not entirely) rain. Still,
though, something kind of interesting to watch.
Once the system finally pulls out late Sunday into Monday, there
could be some lake-effect rain/snow showers for the NW to W wind
snow belts, but models don`t agree on wind trajectories just yet,
nor is it certain that there will be enough moisture left aloft.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 815 PM EDT TUE OCT 8 2019
Under a dry air mass, VFR conditions will prevail at KIWD/KCMX/KSAW
through the forecast period. As a low-level jet moves across the
western Upper Peninsula this evening into tonight, LLWS is
expected to develop at KIWD AND KCMX. Mixing in a downslope ssw
flow could keep gusty winds going through the evening which would
lower the risk of LLWS at KSAW. &&
.MARINE..
South winds 15-20 kts generally expected through Wednesday night
across the lake as high pressure gradually moves away and a new
storm system takes shape over the central U.S. That system
approaches Thursday night and winds back to SE and increase to 25
kts on the eastern lake. On Friday, SE gales are likely on eastern
Lake Superior with winds 25-30 kts on the western lake. Still a bit
uncertain right now just how strong this system will be but high-end
SE gales look possible. Though unlikely, there is a brief window for
storm force gusts Friday afternoon and evening, especially around
Whitefish Point. But to reiterate, there is only a low chance of
this for now. A strong cold front comes through and winds quickly
veer to SW late Friday. Though winds will stay in the 25-30 kt range
Friday night and Saturday, gales look pretty unlikely during this
period as the responsible storm system is expected to weaken pretty
quickly as it drifts eastward across the lake.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...RJC
AVIATION...Voss
MARINE...RJC