Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/14/17
Area Forecast Discussion
National Weather Service Caribou ME
816 PM EST Mon Feb 13 2017
.SYNOPSIS...
Intense low pressure will exit southeast of Nova Scotia
overnight. Weak high pressure will build over the area on
Tuesday. Low pressure will approach from central Canada on
Wednesday and redevelop over the Gulf of Maine Wednesday night.
&&
.NEAR TERM /THROUGH TUESDAY/...
Update...
The intense low which brought blizzard conditions and heavy snow
to portions of the region today is currently located southeast of
Nova Scotia and will move to the east overnight. Snow intensities
are decreasing across the region, though several areas of heavier
snow are still rotating across mostly eastern and Downeast
portions of the forecast area. This snow will gradually diminish
through the remainder of the evening before ending overnight.
Additional snow accumulations will be around an inch or less
across much of the region, with an additional 1 to 3 inches with
the areas of heavier snow. Winds are decreasing across the region.
However, expect blowing and drifting snow to remain a concern
into the the early morning hours across much of the forecast
area. All winter weather headlines remain in place at this time.
High pressure will begin to build across the region late tonight.
Overnight low temperatures will generally range from 5 to around
10 north, to the mid teens Bangor and interior Downeast with
upper teens to around 20 along the Downeast coast. Have updated the
forecast to adjust for current conditions along with snow chances
early tonight. Have also adjusted overnight temperatures.
Previous Discussion...
***Intense Storm continues into the evening***
Snow, winds and drifts causing major concerns across the CWA
especially across the central and downeast areas. Some areas were
closing in on 3 ft of accumulation in portions of SE Aroostook
County and the Central Highlands. Across downeast areas, 15-20
inches reported. Strong llvl convergence and deformation in the
band that dropped up to 3 inches/hr earlier has shifted s per the
latest radar loop. This band was setting up across interior
Downeast Maine and will add to the totals. Across northern Maine,
less snowfall w/some sporadic banding occurring. Winds gusting to
over 40 mph across the downeast region to close to 50 mph on the
coast has led to Blizzard conditions. The intense low will
continue to pull away from the region this evening as it moves s
of Nova Scotia. The latest run of the NAM12 and HRRR matching up
well w/this current conditions and showing things winding down
later this evening. Decided to keep headlines where they are for
now based on the ongoing impacts. Extremely Hazardous or even
Dangerous travel expected into the evening. Blowing snow will be
the issue overnight for all sites. As the low pulls away tonight,
temps will fall back as caa moves back into the region. Gradual
clearing will take place overnight from sw to ne. Readings will
back into the single numbers across the northern 1/2 of the CWA
while central and downeast areas will see low to mid teens.
Tuesday will be a more tranquil day w/high pres briefly ridging
across the region. Temps will moderate into the mid and upper 20s
w/a good deal of sunshine expected.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Our focus going into the mid-week period will be on a new storm
system diving in from Central Canada. Weak high pressure will be
over our region Tuesday evening as a large clipper type storm system
slides into the Great Lakes. The low will track into the eastern
Lakes Wednesday as jet energy rounding the bottom of a trough
nearing the east coast redevelops secondary low pressure east of New
England. Snow will spread across our area Wednesday as the new low
takes shape off the coast. The snow will continue Wednesday night.
Latest forecast guidance is suggesting a moderate snowfall across the
area with amounts from around 5 inches over the far north to 10
inches Downeast. Low pressure is expected to turn northeastward
crossing Nova Scotia Wednesday night and lifting across the
Maritimes on Thursday. Snow will gradually taper off on Thursday
with gusty northwest winds producing some blowing and drifting.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Low pressure will continue to lift northeast and away through the
Maritimes Thursday night through Friday. Skies will remain mostly
cloudy across the north but partially clear Downeast. High pressure
ridging across the area will then bring clearing Friday night
followed by a sunny to partly cloudy day on Saturday. Sunday should
remain dry with a mostly sunny sky Downeast and some increasing
clouds over the north. Some snow showers may brush northern areas
late in the day or Sunday night as a weak low tracks north of the
area.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: MVFR/IFR, with occasional LIFR, conditions are expected
across the region into the early morning hours, improving to
VFR/MVFR levels overnight. Blowing and drifting snow will remain
a concern into the early morning hours. Wind gusts of 40 to 50
mph are still possible Downeast early tonight, with 25 to 35 mph
gusts across the remainder of the region. Winds will decrease
overnight. VFR conditions are expected across the region Tuesday.
SHORT TERM: VFR conditions Tuesday night will lower to MVFR
late Tuesday night then IFR in snow Wednesday morning. IFR
conditions in snow are expected Wednesday into Wednesday night.
IFR conditions will continue through Thursday, possibly improving
to MVFR Downeast late in the day. Conditions will improve to VFR
Downeast Thursday night and become MVFR over the north. MVFR
conditions across the north and VFR conditions Downeast are
expected on Friday.
&&
.MARINE...
NEAR TERM: A Storm Warning remains in effect for the waters into
the early morning hours, with gale conditions expected later
tonight into early Tuesday. Small craft advisory conditions are
expected later Tuesday. Visibilities will be reduced in snow into
the early morning hours.
SHORT TERM: Winds will be light Tuesday night. Winds will
increase out of the southeast ahead of low pressure on Wednesday
and a gale warning may be needed late Wednesday into Wednesday
night as low pressure approaches and redevelops off the coast. An
SCA, or possibly a gale for the offshore waters, will be needed
Thursday into Thursday nights in northwesterly winds as low
pressure lifts northeast into the Maritimes.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning until 5 AM EST Tuesday for MEZ002-004>006-
010-011-031-032.
Winter Weather Advisory until 5 AM EST Tuesday for MEZ001-003.
Blizzard Warning until 5 AM EST Tuesday for MEZ015>017-029-030.
MARINE...Storm Warning until 1 AM EST Tuesday for ANZ050>052.
&&
$$
Near Term...Norcross/Hewitt
Short Term...Bloomer
Long Term...Bloomer
Aviation...Norcross/Bloomer
Marine...Norcross/Bloomer
Area Forecast Discussion
National Weather Service Corpus Christi TX
647 PM CST Mon Feb 13 2017
.DISCUSSION...
Update for 00Z aviation cycle.
&&
.AVIATION...
Very little change to the previous 18Z TAFs.
Tonight...MVFR/IFR. Stratus will work its way back into the region
from the east over the next hour or so. Stronger easterly winds
will remain place throughout the overnight hours with a brief
period of low-level wind shear possible between midnight and 4 AM.
The main issue, besides the cigs, will be the possibility for
thunderstorms to develop ahead of and along a quickly advancing
cold front. Thunderstorms along the frontal boundary have a decent
shot at passing through all our terminals beginning mid-morning.
KLRD may be too far south to see the more intense thunderstorm
activity. Medium to high confidence.
Tuesday...MVFR/IFR back to VFR. Cold front sweeps through by late
morning/early afternoon with clearing behind it. Could see a few
hours of sub-VFR conditions right behind the front but conditions
will rebound nicely to VFR by early/mid-afternoon with gusty
northwesterly winds. High confidence.
&&
.PREVIOUS DISCUSSION... /Issued 356 PM CST Mon Feb 13 2017/
SHORT TERM (Tonight through Tuesday night)...
Satellite imagery shows the upper low near the New Mexico bootheel
moving slowly to the east. This upper low is expected to be over
southeast New Mexico by 12Z Tuesday and then move across the Red
River Tuesday evening. Convection is expected to increase over
northern Mexico into southwest Texas later tonight as the upper
system approaches. Better chances for convection to reach the
Brush Country will be after midnight. A strong upper jet will
move out of northern Mexico tonight into southeast Texas Tuesday
afternoon. Models are similar with the timing of the cold front
moving into South Texas early Tuesday morning with ECMWF still
faster than the other models. With front remaining over the
western Brush Country early Tuesday, there will be a window for a
moderately unstable air mass to move north across the coastal
plains. Models show mixed layer CAPE values reaching at least 1500
J/kg over the coastal counties and higher values over the Gulf
waters. Low to mid level shear is impressive with 0-6 km shear
values from 50-55 knots and 0-1 km shear 20-30 knots. Models show
an area of low pressure forming along the front that may move
toward the VCT area during the morning hours that could lead to
backing flow and an increase in low level storm relative helicity.
Latest RAP guidance shows 0-3 km SRH increasing to around 600
m2/s2 around VCT by mid morning with the other short range model
guidance showing values around 400 m2/s2. SPC Day 2 outlook shows
enhanced threat for severe storms near VCT/PKV area for Tuesday
morning. Will include mention of possible severe storms over the
northern Coastal Bend into the Victoria area Tuesday morning. The
front will move east of the area by 18Z with strengthing northwest
winds expected over the Brush Country during the afternoon. Much
cooler and drier air will move over the region Tuesday night with
lows generally in the 40s.
MARINE (Tonight through Tuesday night)...
An area of low pressure deepening northwest of Cotulla has
increased the pressure gradient over the southern Coastal Bend.
Issued SCA for the southern bays until early this evening. The low
level flow will continue to increase over the Gulf waters ahead of
the surface low forming over the Brush Country. SCA conditions
will likely develop late this evening over the offshore waters and
persist into the afternoon hours before the cold front passes.
A very unstable air mass is expected to move into the coastal
waters Tuesday morning. Expect threat for strong to severe storms
Tuesday morning as convection moves across the waters in advance
of the front. Rain chances will quickly come to an end during the
afternoon as the front moves east. Wind speeds will ramp up
Tuesday evening behind the cold front with a strong northwest flow
expected through the night over the Gulf waters.
LONG TERM (Wednesday through Monday)...
Wednesday and Thursday are expected to be pleasant with cooler and
drier conditions and partly cloudy to mostly sunny skies. As onshore
flow returns, warmer and more humid conditions will return by
Thursday night and Friday. Latest model runs show sufficient
moisture for isold -SHRA`s Thu night and Fri as an upper low swings
across the region. However, this low isn`t expected to bring any
fronts into the area and the warm, humid conditions will continue
into the weekend. Both ECMWF and GFS bring a very potent long wave
trough, dipping far south into MEX, toward the region Sunday and
brings a cold front through the area either Sunday night or Mon
morning. The ECMWF is a bit faster with these features than the GFS.
There is the potential for convection ahead of the front on Sunday
then ending from west to east Monday with drier and cooler
conditions once again filtering into S TX.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 70 79 48 67 42 / 30 70 0 0 0
Victoria 67 74 44 64 40 / 40 90 0 0 0
Laredo 61 70 47 67 44 / 60 20 0 0 0
Alice 67 78 47 68 41 / 40 60 0 0 0
Rockport 69 78 49 65 44 / 30 80 0 0 0
Cotulla 58 69 44 65 41 / 80 40 0 0 0
Kingsville 68 80 47 68 42 / 30 60 0 0 0
Navy Corpus 70 77 50 65 47 / 30 80 0 10 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory from 10 PM this evening to 4 PM CST Tuesday
For the following zones: Waters from Baffin Bay to Port
Aransas from 20 to 60 NM...Waters from Port Aransas to
Matagorda Ship Channel from 20 to 60 NM.
Small Craft Advisory until 8 PM CST this evening For the
following zones: Bays and Waterways from Baffin Bay to Port
Aransas.
&&
$$
GH/77...AVIATION
Area Forecast Discussion
National Weather Service Duluth MN
719 PM CST Mon Feb 13 2017
.UPDATE...
Issued at 719 PM CST Mon Feb 13 2017
A positively tilted long wave trof was moving through the forecast
area at 01Z. This was pushing a surface trof through the area. The
atmosphere has been reasonably dry which has led to mainly virga.
However, ASX has finally reported light rain and CKC light snow.
This will move quickly to the east and be out of the region in the
next hour. Otherwise, clouds will be on the increase ahead of the
next/stronger short wave that will affect the area late tonight.
Made some minor adjustments for these trends.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 412 PM CST Mon Feb 13 2017
A mid-level shortwave trough, with an associated surface cold
front will support chances of precipitation this evening and
overnight for the northern portions of our forecast area. As of
2:30 PM CST this afternoon, some light returns can be seen on the
regional radar mosaic. However, analysis of the model soundings
indicate a layer of dry air near the surface, which should
suppress precipitation from reaching the surface. Thus, reduced
the chances of precipitation from the morning package. The only
ground truth received from the west was one ASOS site that
reported only a trace of precipitation. For now, kept only slight
chance POPs through this evening and most of the overnight period.
The latest RAP model soundings are indicating a lack of deep
saturation through the column, with some low-level saturation
present, indicating more of a drizzle/freezing drizzle
precipitation type tonight and Tuesday morning, eventually
transitioning to more snow as cold air advection enhances behind
the front late Tuesday morning. Where freezing drizzle occurs is
where some slick roads are more likely to develop. The low-level
cold air advection will bring colder 925 mb air during the day
Tuesday with values between -2 to -4 degrees C Tuesday morning
dropping to -7 to -9 degrees C by Tuesday evening for DLH.
Northwesterly winds will become gusty again Tuesday as surface
pressure gradient tightens and up to 50 knots of 850 mb level
winds advances, with winds possibly reaching up to 25 MPH at the
surface, with some isolated higher gusts. As the winds veer from
the northwest after FROPA, 1000-850 mb will become more supportive
for lake-effect snow along the Lake Superior snow belt region.
The heaviest snow amounts are expected to be from the Bayfield
Peninsula, southeast to Iron county. Total snowfall through 00Z
Wednesday could be up to one inch for portions of the MN Arrowhead
and the Gogebic Range.
.LONG TERM...(Tuesday night through Monday)
Issued at 412 PM CST Mon Feb 13 2017
High-amplitude blocking pattern expected to develop Tuesday night
and Wednesday with continued above to much above normal
temperatures a low precipitation chances through the long term.
An impressive shortwave trough will be centered over the western
Great Lakes Tuesday evening with high amplitude ridging building
over the western CONUS and western Canada. As the trough pivots
eastward toward New England by Wednesday morning, it will deepen
and close off. Lake-effect snow showers are possible in the
northwest Wisconsin snow belt through Tuesday evening, but should
taper off early Wednesday morning as upstream moisture shifts
eastward.
The closed upper low will anchor the eastern side of an Omega
Block over the western two-thirds of North America. By late
Wednesday afternoon the high amplitude, nearly meridional, arm of
the block will be positioned over the Northland. A meager stream
of moisture will support stratus, but otherwise conditions should
remain dry. Temperatures will trend cooler for Wednesday with the
cold airmass pouring into the area.
The closed upper low is forecast to drift farther eastward
Wednesday night to near Nova Scotia by late Friday night. The high
amplitude ridge will result in continued warm conditions across
the Northland and dry weather through Friday. By Friday night a
northern stream shortwave trough will move across the Canadian
Prairies, further flattening the ridge. The passing low will bring
an uptick in cloud cover, but dry conditions should continue in
the Northland. Behind that system, a return to a quasi-zonal
pattern is expected with quiet weather continuing through Sunday.
Deterministic and ensemble guidance is split on the potential for
precipitation late Sunday night and Monday. For now kept a mix of
rain and snow in the forecast with chance POPs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 540 PM CST Mon Feb 13 2017
A trof of low pressure was moving past the terminals at the start
of the forecast. Due to a lack of good moisture, only some mid
clouds were found in the vicinity. This trof is being pushed along
by an upper short wave trof. These features will push east of the
terminals by 04Z. VFR is expected until about 09Z when some MVFR
clouds are expected to drop south out of Ontario. Gusty surface
winds are forecast to return by 09Z over northern MN, and reach
northwest WI by 14Z. Some showers will be in the vicinity of
HIB/DLH/HYR by late morning or early afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 27 31 9 25 / 0 10 0 0
INL 23 28 2 23 / 20 10 0 0
BRD 27 33 10 30 / 0 10 0 0
HYR 29 34 11 26 / 0 20 10 0
ASX 29 35 14 26 / 10 30 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...GSF
SHORT TERM...JTS
LONG TERM...Huyck
AVIATION...GSF
Area Forecast Discussion
National Weather Service Goodland KS
413 PM MST Mon Feb 13 2017
.SHORT TERM...(This afternoon through Tuesday)
Issued at 148 PM MST Mon Feb 13 2017
Closed upper low is centered near the southern Arizona/New Mexico
border, with SW diffluent flow over the southern plains. Plume of
mid- upper level moisture extends northward over our CWA. A
shortwave trough is currently moving over the northern plains with
an axis of subsidence mid-upper level dry air across northern
Wyoming/Nebraska. Radar shows light precipitation (pockets of
moderate) along covergence zone roughly along/south of I-70
corridor transitioning eastward.
This afternoon-evening: Short range and high resolution guidance
has had good handle on precip trends, and with this in mind we
should continue to see activity track eastward and diminish in
coverage late this afternoon and early this evening. RAP soundings
as of 18Z continues to show warm enough Tw aloft to support rain
reaching the surface this afternoon/evening and with above
freezing temps this should limit any frozen precip potential.
Tonight-Tuesday: Large scale subsidence and much drier air
transition over our CWA keeping conditions dry. Windy may remain
high enough (around 8-11kt). Tds will be low enough that some
cold spots could drop to the upper teens tonight, however winds
around 10kt may limit radiational cooling potential. I stayed in
line with consensus showing mid 20s for most. Temps aloft change
little from today on Wednesday, however the benefit of sunny skies
should allow highs to warm to around 50 or the low 50s (maybe a
few locations in the mid 50s). Increased mixing could help tap
into LLJ developing on back side of upper low resulting in windy
conditions during the day (gusts around 30 mph). RH remain in the
upper 20/30s, so critical fire weather conditions are not
anticipated.
.LONG TERM...(Tuesday night through Monday)
Issued at 157 PM MST Mon Feb 13 2017
Forecast concerns will be how warm does it get on Thursday and
chance of precipitation at the beginning of next week. Satellite
showing an amplified flow from the Pacific into North America.
Tuesday night...ridging aloft builds into the western portion of the
country which northerly flow over the area. Northerly winds calm
down and go much lighter, especially in the east. So nudged the mins
down a few degrees.
Wednesday/Wednesday night...Models continue to build the ridge into
the region although they differ on how fast/strong this is done.
Models are warming temperatures up, and what the builder gives me
makes sense, and made no changes.
Thursday...Combination of ridging/split flow develops over the
central portion of the country. Models differ on the details.
However it does look fairly certain that area will see rather deep
westerly flow. So per the latest data and collaboration, I did raise
the maxes.
Thursday night through Monday...models over the entire country are
having a very difficult time in resolving the flow pattern. The
problems/differences increase/get worse with time. In general the
models are showing a couple of open waves affecting the area at the
end of the period. Although the Canadian is still insisting on a
closed circulation moving across the area.
The forecast builder is giving me two different periods of pops.
The first is Sunday afternoon into the evening with the next chance
Monday afternoon running into the nighttime hours. The first wave
looks the strongest at this time with the Ecmwf bringing in a potent
negatively tilted system. Based on the above/current model
differences, am content to leave the current pops. Although if
models move toward the Ecmwf, the pops may need to be raise plus
some thunderstorm may have to be inserted.
Since at the end of the period with the current model disagreement
in place, am also content with leaving the pops in for Monday.
Overall made no changes to what the builder gave me for this period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 413 PM MST Mon Feb 13 2017
VFR conditions will continue through the TAF period at both KGLD
and KMCK terminals. Virga or a few sprinkles will be possible
early in the TAF period at KGLD, but chance for any precip was low
enough not to keep mention of VCSH in TAF. Northerly winds will
increase by midday Tuesday, with increasing winds aloft behind
departing upper level system. Expect afternoon gusts 20-25kt at
both terminals (strongest at KGLD).
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
Area Forecast Discussion
National Weather Service Memphis TN
923 PM CST Mon Feb 13 2017
.UPDATE...
Clouds are quickly spreading in from the west this evening. The
clouds are ahead of a low pressure system currently located
across South Texas. Rain from the system has already spread into
Southwest Missouri and Northwest Arkansas this evening. The
latest HRRR run shows the rain spreading into Northeast Arkansas
after 4 am. Will bump up POPS and make some minor adjustments to
lows as clouds will keep temperatures from dropping as much
especially along and west of the Mississippi River. Update will be
out shortly.
KRM
&&
.DISCUSSION... /issued 327 PM CST Mon Feb 13 2017/
Our temperatures have warmed from the 30s this morning well into
the mid and upper 50s this afternoon as a weak ridge builds
northerly across the area and surface high pressure shifts across
the northern portion of the area. To our West another trough is
digging across West Texas. As a result we will be under Southwest
flow by tomorrow morning with significant cloud cover returning to
the region. Guidance has been back and forth with respect to the
track of a surface low Tuesday into Wednesday...currently
reverting back to a track across Central Mississippi into Central
Alabama. This would result in a drier...forecast...featuring light
rain instead on convectively enhanced showers. Nevertheless...we
should see some rainfall Tomorrow and Tomorrow night with the
heaviest rain tomorrow night over north Mississippi. If the low
track shifts to the North again heavier rain and higher rain
totals would be likely farther North.
Mainly do to clouds and rain...high temperatures will trend a bit
cooler tomorrow and Wednesday but rebound after Midweek. No
strong or severe storms are expected.
Thursday and Friday we will be on the northern edge of strong
Surface high pressure centered along the North Gulf Coast. By the
weekend highs are expected to be back in the middle 60s. Another
trough will shift out of the plains, but moisture looks limited
until Sunday afternoon. It may be fairly cloudy...but should be a
dry and mild weekend.
30
&&
.AVIATION...
VFR conditions expected through Tuesday morning. Clouds and some
rain will spread into the region as low pressure develops and
moves into the Lower Mississippi Valley on Tuesday. Rain will
spread across the region Tuesday morning with cigs lowering to
MVFR by afternoon at KJBR...KMEM and KTUP. Rain should remain
north of KTUP through the end of the period wth VFR conds there
through 00z. Northeast winds will average around 5 kts through the
period.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
649 PM EST Mon Feb 13 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 330 PM EST MON FEB 13 2017
12Z raobs/latest wv imagery and RAP analysis show a nw flow aloft
over the Great Lks btwn upr rdging over the Pac nw/wrn Canada and
some upr troffing over ern NAmerica. The Upr Lks are dominated by a
steady wsw flow btwn a hi pres rdg over the Lower Lks/OH River
Valley and lo pres over nrn Manitoba associated with a pair of
shrtwvs digging sewd thru scentral Canada. The first of these
disturbances is moving thru srn Manitoba, but since the llvls shown
on the upstream 12Z raobs are so dry, only an area of mid/hi clds
are present and moving into Upr MI. The second shrtwv is closer to
the sfc lo center over nrn Saskatchewan. Despite the arrival of the
hi clds, the wsw flow in the presence of incrsg sun angle has lifted
sfc temps well into the 40s at most places away fm cooling off Lk MI.
Fcst concerns in the short term focus on fcst lo cld/pcpn trends/
pops tngt and Tue associated with upstream shrtvs.
Tngt...Shrtwv now over srn Manitoba and accompanying deep lyr
forcing/lo pres trof are fcst to swing thru Upr MI. Many of the
models show expanding llvl mstr/lo clds and even some pcpn as early
as this evng over mainly the nw cwa, but dryness of the upstream
airmass suggests this fcst is overdone and perhaps related to poorly
handled sn melt moistening. Delayed the arrival of the lo clds/lgt
pcpn until late and restricted mention of any sn showers/flurries to
the nw cwa, where the strengthening wnw flow wl upslope in the wake
of the trof passage, and over the ern cwa where there could be some
moistening off Lk MI and greater ascent on the cyc side of shrtwv
track. Fcst h85 temps to -6C to -8C wl limit the intensity of any
sn showers. Steady sw veering wnw winds and a good deal of mid/hi
clds wl limit the diurnal temp fall.
Tue...Dpva/deep lyr qvector cnvgc associated with the second shrtwv
are progged to arrive in the mrng, with 12hr h5 hgt falls aprchg
100m during the day as the shrtwv digs thru the area. In tandem with
sharpening cyc wnw flow/caa that is fcst to drop h85 temps as lo as
-14C over the nw cwa by 00Z Wed, expect incrsg pops/intensity for
sn showers, mainly in the favored upslope locations near Lk Sup.
The sharpening pres gradient that wl support incrsg h925 winds up
to 40 kts and destabilization accompanying the caa wl result in
gusty winds and some blsn as well. Not out of the question an advy
for winds/sn/blsn wl be needed eventually, especially over the nw
and near Lk Sup e of Marquette.
.LONG TERM...(Tuesday night through Monday)
Issued at 342 PM EST MON FEB 13 2017
Cold air to the tune of -17C at 850mb will drop into the area
following a shortwave Tue night. The temps will moderate some on
Wed, but will increase more rapidly Wed night into Thu as a SFC
ridge moves through. This will lead to moderate LES in NNW wind snow
belts Tue night that will gradually diminish W to E Wed and Wed
night. Expect 2-5 inches in NNW wind snowbelts Tue night and up to
another 2 inches Wed, but only light amounts Wed night. NNW winds
gusting to 45 mph near central and eastern Lake Superior Tue night
and gradually diminish late Tue night through Wed, creating
widespread blowing and drifting snow in those areas.
Otherwise just watching the warmth coming in over the weekend with
building upper ridging. Could see highs up to 50F Sat and Mon. Looks
dry right now for the weekend, but could see widespread rain
sometime early-mid next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 648 PM EST MON FEB 13 2017
VFR conditions this evening will give way to MVFR overnight at
KIWD/KCMX in the wake of a passing sfc trof and wshft to upslope
westerly direction. Cigs probably won`t fall to MVFR at KSAW until
Tue morning. Sct -shsn will develop on Tue as a vigorous disturbance
drops se into the Upper Great Lakes. While conditions should remain
MVFR at all terminals, not out of the question for some periods of
IFR at KCMX where winds will be gusting over 30kt, adding some blsn
to the vis restriction.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 330 PM EST MON FEB 13 2017
Sw winds up to 25-30kts tonight will veer to the wnw and increase up
to gale force by late morning on Tue over most of Lake Superior as a
strong upper disturbance slides into the Upper Lakes and sharpens
the pres gradient. Since colder air will be arriving at the same
time and decreasing the overwater stability, confidence is hi enuf
to upgrade gale watches to warnings. These gales will persist into
Wed, when an approaching hi pres will cause winds to diminish under
20kts by Thu. Ssw winds up to 25kts will then prevail on Fri/Sat on
the western flank of the hi pres passing to the e.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 7 AM Tuesday to 1 PM EST Wednesday for LSZ266-
267.
Gale Warning from 7 AM Tuesday to 7 AM EST Wednesday for LSZ264-
265.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...Titus
AVIATION...Rolfson
MARINE...KC