Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/10/19
Area Forecast Discussion
National Weather Service Duluth MN
1054 PM CDT Tue Apr 9 2019
.UPDATE...
Issued at 1012 PM CDT Tue Apr 9 2019
Opted to issue a Lakeshore Flood Watch for the western tip of Lake
Superior. With waves in excess of 15 feet, a long period of strong
winds (some to 50+ mph), and the potential for ice chunks to be
embedded in the waves which in themselves would cause significant
damage and erosion, there were enough indicators to raise this
flag.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 440 PM CDT Tue Apr 9 2019
Generally quiet conditions expected through Wednesday afternoon
before a potent spring snow storm impacts the Northland for
Wednesday night through Thursday.
For tonight, mostly dry conditions are expected across the
region. The mid-level trough of low pressure that brought some
very light snow to areas along the Iron Range and points southeast
this afternoon will continue to move out of the region, to the
southeast. A large area of high pressure will be situated over
Hudson Bay, which should expand southward into the Northland,
keeping conditions mostly dry. Meanwhile, the surface low pressure
that will bring accumulating snow to the region later in the week
will develop via lee cyclogenesis over eastern Colorado and
advance eastward into the central Great Plains. Between the high
to the north and the low to the southwest, the flow will become
more east to northeast tonight and the surface pressure gradient
will tighten. This will result in some very gusty winds for
Wednesday, and perhaps some lake induced clouds and light snow or
flurries near the western arm of Lake Superior. Both the RAP and
the NAM model guidance at KDLH shows a shallow saturated layer in
the low-levels, along with persistently steep low-level lapse
rates. Chances of precipitation in the Twin Ports will be small
due to the limited moisture available, ramping up after midnight
and diminishing late Wednesday morning. Confidence is fairly low
regarding these chances of precipitation, but are much higher for
the strong northeast winds off Lake Superior. Wind gusts along
Lake Superior and points southwest could range between 25 to 35
mph Wednesday afternoon. High temperatures Wednesday will range
from the lower 30s along Lake Superior to the upper 30s to lower
40s farther inland.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 440 PM CDT Tue Apr 9 2019
The main concern for the long term continues to be the powerful
storm forecast to bring heavy snow and strong winds to the region
Wednesday evening through Friday afternoon.
A strong storm system will move out of the Plains early Wednesday
evening , across the Upper Midwest Thursday and Friday, and into
northeast Ontario by early Saturday morning. The system will have
access to rich Gulf moisture and is expected to be a prolific snow
producer. There are some concerns regarding poleward moisture
transport, especially Thursday and Thursday night. Thunderstorms
are possible along the warm front in southern Minnesota and
southern Wisconsin Thursday morning with another round of storms
possible Thursday afternoon and evening along the cold front in
Wisconsin and Illinois. Strong winds will accompany the storm
which may result in near-blizzard conditions from the Brainerd
Lakes east to the I-35 corridor and into northwest Wisconsin. The
Twin Ports area may also experience near-blizzard conditions
Thursday afternoon and evening. Snow accumulation of 8 inches or
more is forecast from central Minnesota into the Arrowhead and
over all of northwest Wisconsin. Northwestern portions of
Koochiching County can expect 2 to 5 inches of accumulation. Warm
air aloft may extend as far north a Spooner to Hurley line, which
may change snow to rain or a mix for a time early Friday morning.
Snow will taper off from southwest to northeast on Friday and
winds speeds will quickly diminish as the low fills and departs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 644 PM CDT Tue Apr 9 2019
Northerly winds will become northeasterly by morning with winds
strengthening throughout Tuesday as a surface low moves towards
the Northland. Winds will be highest near the head of Lake
Superior with sustained winds between 15 and 20 kt gusting to
around 30 kt by the afternoon. Skies will remain VFR this evening,
but MVFR skies are expected overnight and tomorrow morning for
most locations. Light lake effect snow flurries are possible in
the Twin Ports late tonight into tomorrow morning, but visibility
restrictions are not anticipated. Some partial clearing is
possible Tuesday afternoon with skies becoming VFR.
Strong winds will continue Wednesday night through early Friday
morning with heavy snow accumulating snow expected. Snowfall
rates up to one inch per hour are possible along with near-
blizzard conditions especially near the head of Lake Superior.
&&
.MARINE...
Issued at 1028 PM CDT Tue Apr 9 2019
A powerful spring storm will bring widespread gales Thursday
morning into Friday morning as a low pressure moves from Iowa into
the Lake Superior region. Strong northeast winds will develop
Wednesday afternoon and continue through Friday morning. While
gales will likely be the predominant wind speed, there is some
concern for stronger winds so we will maintain a Storm Watch
across the nearshore waters. With a fetch straight across Lake
Superior for around 48 hours, wave heights as high as 15 feet are
possible. Some ice cover along the South Shore of Lake Superior
along the Bayfield Peninsula will likely be pushed towards the
western shores of Lake Superior, creating hazardous conditions for
ships and wave-watchers in Duluth`s beach areas. Whiteout
conditions will be possible at times due to high winds and heavy
snow. Winds and waves will begin to weaken Friday afternoon as the
surface low moves northeast over Lake Superior and winds turn
northwesterly.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 26 34 25 30 / 20 20 60 80
INL 23 42 22 35 / 10 0 0 50
BRD 26 40 26 34 / 0 30 70 80
HYR 24 41 27 35 / 10 30 70 80
ASX 28 36 27 32 / 20 10 60 80
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Watch from late Wednesday night through Friday
morning for WIZ001>004-006>009.
Lakeshore Flood Watch from late Wednesday night through late
Thursday night for WIZ001.
MN...Winter Storm Watch from late Wednesday night through Friday
morning for MNZ033>038.
Winter Storm Watch from Thursday morning through Friday morning
for MNZ011-012-018>021-025-026.
Lakeshore Flood Watch from late Wednesday night through late
Thursday night for MNZ037.
LS...Storm Watch from late Wednesday night through Friday morning for
LSZ121-140>148.
&&
$$
UPDATE...Wolfe
SHORT TERM...JTS
LONG TERM...Huyck
AVIATION...JS
MARINE...JS
Area Forecast Discussion
National Weather Service Grand Forks ND
847 PM CDT Tue Apr 9 2019
.UPDATE...
Issued at 847 PM CDT Tue Apr 9 2019
No updates needed at this point.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 321 PM CDT Tue Apr 9 2019
Temperatures and precip in our far southern counties will be the
main issues for the period.
Quiet and cold tonight with weak upper ridging ahead of the trough
to our west and high pressure parked over central Canada and into
the Northern Plains. Temperatures this afternoon have stayed below
freezing across most of the CWA, with the exception of southeastern
ND and west central MN. The surface high to our northeast will
continue to bring cool, dry air into the area overnight. Precip on
radar over south central ND into eastern SD will not make much
progress into our southern counties tonight thanks to the high, so
think that precip will hold off until later tomorrow afternoon.
There will be a fair amount of cloud cover however, which along with
winds around 10 kts will keep temps in the 20s overnight even with
some pretty dry dew points.
Tomorrow, the upper trough will move into the Central Plains, with
the main surface low well to our south over KS/Neb. With the high
still over Ontario, precip will still be struggling to make its way
northward. However, do think we will see some saturation near the SD
border by Wednesday afternoon, so have some rain/snow mix starting
but any accumulation will hold off until later. Thus, much of the
day on Wednesday will be quiet and well below normal with highs in
the 30s to low 40s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 321 PM CDT Tue Apr 9 2019
Confidence continues to increase that a strong storm system will
impact the Plains/upper Midwest region Wednesday night through
Friday morning. This storm will bring the potential for impactful
winter weather to southeast ND and west central MN, but details
remain uncertain.
Wednesday night through Friday...
Afternoon water vapor imagery shows a stout upper level low
gradually deepening over the west coast of the CONUS thanks to
moderate to strong mid level cold advection. This low is expected to
continue to deepen before ejecting out into the central Plains
tomorrow. As this occurs, rapid intensification of a lee cyclone
will promote an equator-ward flux of colder arctic air currently
residing along the international border and into Canada per recent
RAP analyses.
As the low deepens and moves into the central plains, strong warm
advection will take place over the eastern Dakotas and IA/MN
region. Nearly all deterministic guidance shows mid-level
frontogenetical banding within this frontal zone augmenting broad
synoptic scale lift over the region. This, combined with the
southward moving colder air, will promote widespread snowfall with
bands/pockets of heavier snow amounts. Snowfall will continue as the
low progresses towards the Great Lakes region and deformation
banding sets up somewhere over the eastern Dakotas/southwest MN
region. Snowfall is expected to begin across the southern Valley
late Wednesday night/early Thursday morning and could linger until
Friday afternoon.
With the strong surface low expected to pass relatively close to the
region (across southern MN/northern IA), strong northeasterly to
northerly surface winds are expected and could cause some blowing
snow impacts where strong winds are concurrent with heavy snowfall.
The strongest winds are expected around mid day Thursday, roughly
the same time as when confidence in snowfall is highest. This
suggests that the time of maximum impacts (such as travel
difficulties) will be from Thursday morning into Thursday afternoon.
Both recent ensemble and deterministic guidance over the past 24
hours have shown a notable shift to the north and west of the
surface low`s track and subsequently the placement of snowfall.
While the heaviest snowfall is still expected across eastern SD and
northwest MN, warning criteria snowfall (6+") has become more likely
across southeast ND and west central/parts of northwest MN. This has
prompted an expansion of the current watch to the northwest.
However, it should be stressed that there remains considerable
uncertainty with this system. High ensemble spread coupled with high
run-to-run variability in deterministic models does not lend a lot
of confidence in snowfall and liquid equivalent amounts.
Additionally, deterministic guidance continues to suggest that dry
air moving southward out of Canada could undercut snowfall amounts
north of the Highway 200 corridor - introducing further uncertainty
to the forecast. Changes to snowfall totals are expected as the
forecast is further refined tomorrow when the upper level wave is
better sampled and comes into range of higher-resolution guidance.
Saturday through Monday...
Generally dry weather is expected for the weekend and surface high
pressure moves into the region. Temperatures will rebound gradually
with highs in the 40s and low 50s expected by Sunday and Monday.
Overnight lows will remain below freezing through early next week.
Rain and snow chances increase Monday and Tuesday as an upper level
wave moves through the region. At this time mainly rain is expected
as temperatures will mostly remain above zero, but some light snow
can`t be ruled out as temperatures drop below freezing overnight.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 644 PM CDT Tue Apr 9 2019
The MVFR clouds have cleared out of KBJI and look to clear out of
KTVF shortly. Unless they back up again, these two locations
should stay in the VFR range overnight. There is a little more
uncertainty for the other TAF sites. If nothing else, KDVL, KGFK,
and KFAR will either stay where they are currently at, or they
may rise just a little more, potentially into the lower end of VFR
conditions. Wind should stay on the lower end tonight, but will
become a little more gusty Wednesday afternoon into the early
evening.
&&
.HYDROLOGY...
Issued at 321 PM CDT Tue Apr 9 2019
Flooding from snowmelt continues within the main stem Red River and
its tributaries. At Halstad, there was an increase to the crest now
expected to reach 38.5 with water levels to remain high for several
days. The Wild Rice River in Minnesota at Hendrum had an increase in
forecast crest at 32 feet pushing into major flood stage. The Snake
River at Alvarado had an increase in forecast crest at 108.5 feet
pushing into moderate flood stage. Crest is not yet within the
forecast range at Pembina and Drayton (ie crest expected more than 7
days away).
Ice is impacting locations like Drayton and Oslo on the Red River as
well as locations within the Pembina and Red Lake rivers. This may
cause sudden and unexpected fluctuations in water levels. Backwater
from the main stem Red River is affecting the Sheyenne River at
Harwood and West Fargo Diversion, the Wild Rice River in Minnesota
at Hendrum, Marsh River at Shelly, and Sand Hill River at Climax
effectively preventing flood waters from receding. The Sheyenne
River at Kindred, local flows appear to be trailing off and some ice
effect has been reduced, although the substantial volume of water
from upstream will be working it`s way through over the next several
days.
Some locations in the southern Red River Basin that are cresting or
have already crested include Hickson, Fargo, and Wahpeton on the Red
River as well as those on the Buffalo and Maple rivers. Fargo has
crested with a preliminary peak of 35.03 feet around 9 PM on April 8
placing it as the 10th highest crest on record, preliminarily. Top
10 crests are forecast for all other forecast points on the Red
River north of Fargo.
The Red River at Wahpeton was updated with new re-rise into moderate
flood stage next Tuesday due to this mid-week`s forecast snow and
subsequent melt in the far southern Red River Basin. Confidence in
this re-rise is low however due to low confidence in snow forecast.
This may cause a re-rise in area water levels or lengthen the period
of flood after snow melts and moves through the basin in the future.
Confidence remains low on exact impacts to the river system from
additional snowmelt associated with the mid-week system, however
confidence is high that this will not increase any crests within the
current flood wave moving through the basin. All morning updates to
river forecasts have accounted for forecast precipitation from the
mid-week snow.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Storm Watch from Wednesday evening through Friday
afternoon for NDZ038-039-049-052-053.
MN...Winter Storm Watch from Wednesday evening through Friday
afternoon for MNZ003-029>031-040.
Winter Storm Watch from Thursday morning through Friday
afternoon for MNZ002-017-022>024-027-028-032.
Areal and river point flood warnings continue across portions of
the region. Refer to the latest flood warnings and statements for
detailed information on specific locations.
&&
$$
UPDATE...Godon
SHORT TERM...JR
LONG TERM...AM
AVIATION...Godon
HYDROLOGY...CJ
Area Forecast Discussion
National Weather Service Key West FL
1009 PM EDT Tue Apr 9 2019
.CURRENTLY...
Showers and a few thunderstorms moved up the Keys late this
afternoon and early this evening. As of 10 pm, MTH had picked up
0.97" of rain today. MTH likely had one of the heavier rainfall
amounts from throughout the Keys. However, even heavier activity
passed E-NE through the Straits and south of the island chain. At
10 pm, the Keys were in a lull of merely light rain. Rain-cooled
air has helped temperatures cool off into the lower 70s.
A southern stream upper trough axis is currently moving east
acorss the Central Gulf. In advance of the trough, strong upper
level southwesterlies prevail over the Keys. This has brought up
plenty of deep-layer moisture from Central America. Indeed, the
00z KEY sounding revealed an integrated Precipitable Water (PW)
value of a very moist 1.98", and the sounding was almost saturated
and moist adiabatic from 6,000 feet to near 40,000 feet. So the
air mass is plenty moist with a tall and very skinny CAPE
profile, with the Most Unstable CAPE value of 259 J/kg.
.SHORT TERM...(Tonight-Wednesday)
Another round of showers and thunderstorms appears to be on the
way to the Keys overnight. A boundary is currently draped
southwest from the Fort Myers area over the southeast Gulf.
Meanwhile, a 100-knot jet streak at 300 mb will be exiting across
the Yucatan from the base of the Central Gulf upper through early
Wed morning. Over the Keys, it will enhance upper-level
divergence and large-scale lift overnight. Given the moist and
marginally unstable air mass, the low-level boundary over the
Southeast Gulf should act as an effective focus for convective
development overnight. Already, a narrow line is starting to
develop, but lightning has not yet developed. Recent runs of the
HRRR have been consistent in blossoming convection and pushing the
line to the Keys around 06z-09z. By that time, the line will be
moving slowly, so there is the potential for locally heavy
rainfall amounts in excess of 1", especially if convective cells
can start training. Have updated the forecast this evening, mainly
to maintain a high chance of showers and thunderstorms through
the night.
The line will eventually move southeast into the Straits and
beyond by 11-14z. The upper trough axis will follow late Wed
morning. Once the trough axis passes, the mid-upper level air mass
will dry out quickly, and upper level heights will start to rise.
Skies will become increasingly sunny, and precip chances will
taper off quickly on Wed afternoon. The forecast is completely
dry starting Wed evening.
&&
.LONG TERM...(Wed night-Tuesday)
From Previous Discussion: Gentle to moderate west winds will
shift northwest then collapse Wednesday night as the low over the
southeast moves off the Atlantic coast and begins filling. While
there is essentially no cool air advection expected, dew points
will slip into the upper 60s. As a result, radiational cooling
should happen Wednesday night, driving temperatures down to near
70 degrees. Slim to no rain chances are expected.
Through the remainder of the week a robust high pressure system
will roll eastward off the Atlantic coast. Light and variable
winds will gradually firm up out of the east to southeast Thursday
night into Friday. Above normal temperatures are expected with dew
points gradually climbing back toward the mid 70s.
&&
.MARINE...
One more line of showers and thunderstorms will move across the
Keys waters overnight and early Wed morning. As it passes, expect
a sharp shift and pickup in wind, out of the northwest at first.
For most of Wed, moderate and locally fresh westerly breezes will
prevail as weakening low pressure moves across the Southeast
States and exits into the Atlantic. The speed of W-NW winds will
collapse on Wed night, as low pressure exits the picture and
gradients flatten.
High pressure will emerge off the US Atlantic coast through the
back half of the week, resulting in winds strengthening out of the
east then southeast Thursday night into Friday.
&&
.AVIATION...
Experiencing a lull in the rain currently as of 10 pm. Radar
shows a new line of convective showers and thunderstorms
developing over the Gulf about 100 miles northwest of the EYW
terminal. This line is forecast to move southeast and reach the
island terminals around 06-08z. The line will be moving slowly by
that time, so it could take until 11z- 12z for these showers and
thunderstorms to clear the terminals. Expect cloud decks to thin
and scatter out thereafter.
&&
.CLIMATE...
On this date in 1951, 1/2" to 3/4" hail fell in Key West for 7
minutes (the first hail since July 1926).
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...Haner
Aviation/Nowcasts....Haner
Data Collection......99
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Area Forecast Discussion
National Weather Service Marquette MI
721 PM EDT Tue Apr 9 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 325 PM EDT TUE APR 9 2019
WV imagery and RAP analysis indicated a well-defined shortwave
trough moving through the Upper Great Lakes this afternoon in a
cyclonic wnw flow aloft. Forcing associated with this shortwave (mid-
level q-vector convergence) has supported scattered to numerous snow
showers this afternoon with greatest coverage northeast half where
850 mb temps are marginally cold enough (around -7C) to provide some
enhancement to lake showers in nnw flow.
Tonight, expect snow showers to diminish toward evening as the
shortwave and associated forcing slides se of the area. As high
pressure builds through northern Ontario into the Upper Great Lakes,
winds will veer from nnw to nne this evening and ne overnight and
will shift the focus of any remaining snow showers into north
central Upper Michigan. Moist weakly cyclonic low level flow with
870-850 mb temps around -10C could still result in a light coating
of snow for higher terrain locations, mainly over western Marquette
and Baraga counties.
.Wednesday, sfc ridge builds in more prominently as low-level
northeast flow becomes increasingly anticyclonic and diffluent.
Expect low clouds to eventually scour out in the afternoon from
increasing subsidence and influx of dry air. Could be some increase
in mid-high clouds along the Wi border counties by late afternoon.
Prevailing onshore ne flow through the period under cloud cover will
result in near normal temps tonight, in the mid to upper 20s. Highs
Wed will range from the lower to mid 30s near Lake Superior to the
upper 30s to around 40F south and east, farther away from the
moderating influence of the lake.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 520 PM EDT TUE APR 9 2019
An active storm track will prevail across the CONUS for at least the
next 10 days under a progression of Pacific shortwaves dropping se
across the western CONUS and then lifting ne across the central and
eastern CONUS. The first shortwave has moved onshore over the w
today, and it will lift across the western Great Lakes late this
week. The second wave will drop sharply se along the W Coast into
far NW Mexico late this week, then lift across the Ohio Valley/Great
Lakes early next week. The third shortwave will drop se across the
western CONUS early next week and then probably lift ne toward the
Great Lakes during the mid part of next week. While there is
uncertainty in whether the fcst area will be affected by the second
shortwave, pcpn amounts across Upper MI will be above normal over
the next 10 days due to the first system moving across the area late
this week and due to the third system that should affect the area
during the middle of next week. The first system will bring a wintry
mix of pcpn to the fcst area with all areas seeing at least some
snow accumulation. Significant hvy/wet snow accumulations will be
possible over the nw. The second wave will likely pass too far to
the se to produce pcpn here early next week, but if the track does
shift nw, would be looking at another wintry mix. The third system
will likely bring a wet period during the middle part of next week.
As for temps, blo normal temps will prevail most days thru the first
half of next week.
Shortwave trof currently moving across the western CONUS will close
off into a mid-level low as it shifts out over the central Plains
Wed night. Associated sfc low will reach its lowest pres in the low
980s mb over se Nebraska by 12z Thu. Strong downstream
waa/isentropic ascent (40-50kt generally oriented perpendicular to
isobars) and band of strong mid-level fgen will be spreading toward
Upper MI during Wed night. However, given a good easterly feed of
low-level dry air emanating from strong sfc high pres centered over
far northern Ontario/southern Hudson Bay, prefer the slower non-NAM
solutions Wed night with regard to the northward progress of pcpn
and the pronounced warm nose surging n up at around 700mb. Expect
snow to move n into southern Upper MI, probably in the 09z-12z time
frame.
On Thu, the strong waa/isentropic ascent and band of strong mid-
level fgen will quickly shift n across the area. Thus, snow will
advance steadily n across the rest of the fcst area Thu morning into
early Thu aftn. Should be the potential for several inches of snow
given mixing ratios of 4-5g/kg in the 700-750mb layer. As the day
progresses and on into Thu night, warm conveyor pcpn will develop on
the front side of the trof within zone of strong 850-700mb moisture
transport. This pcpn will begin streaming n into the Upper Lakes.
Given the continued waa as this pcpn streams n, temp profile is
likely to push above 0C somewhere in the 850mb to 700mb layer across
at least the e half of the fcst area. NAM is very aggressive with
this warming, sending warm nose temps to at least 3C across all of
Upper MI. For now, have discounted the NAM since it is the outlier.
How fast the warming occurs will obviously be key to the snow
accumulations. As it stands now, there is at least an increasing
potential for more of the pcpn to end up as rain over the s central
into the eastern fcst area. During the transition, there may be some
-fzra for a time. Not expecting this to be a big issue. However,
if pcpn does not translate far enough e, the strong high to the
ne will be able to maintain a better feed of dry low-level air
into the fcst area, increasing the potential for more sustained
fzra. This will be something to watch. Then, depending on how the
warm conveyor pcpn organizes/develops, some hydro issues may
develop with ponding water in low-lying areas/drainage areas and
quick rises on smaller streams. Will also be something to
monitor. Out w, pcpn has a better chc to remain all snow, but
with the fgen lifting n of the area on Thu, and then the warm
conveyor probably setting up largely to the e of there, snow may
end up on the lighter side after the initial surge on Thu.
As for headlines, will retain the watch headline given the ongoing
uncertainty in ptypes and trends toward a warmer solution, but will
push back the start time to better align roughly with the expected
pcpn onset. Generally, it appears total snow accumulation potential
is trending downward. Total snow accumulations thru Thu night will
probably end up more in the 2-5 inch range e to 5-8 inch range w.
Some light rain/snow will linger on Fri as the weakening mid-level
low tracks across the Upper Lakes and potentially on Sat as well.
The next shortwave lifting out of far northern Mexico this weekend
will make a run ne early next week. ECMWF has already had a farther
nw track for the last 2 runs, far enough nw to support some
snow/rain across much of the fcst area. The GFS/CMC have shown a
slight nw trend with the 12z run. The 00z GFS/CMC ensembles did not
really show any support for a track far enough nw to impact the fcst
area, but still, will be something to monitor early next week.
The next shortwave will lift out across the Plains midweek, but
probably won`t affect the weather here until Wed. Early indications
point toward this system being a potential significant pcpn
producer.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 719 PM EDT TUE APR 9 2019
Lake-effect snow showers that have been persisting will eventually
taper off overnight at KSAW, with activity already tapering off at
KCMX. Although lowered ceilings look to remain in place at all
three terminals through the overnight period, there does appear to
be some break in sight tomorrow, with VFR looking to return
briefly. Generally light winds through tomorrow morning will
become gusty later in the day as a low pressure system approaches
the region.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 325 PM EDT TUE APR 9 2019
Winds will remain at or below 25 knots into Wed morning before
northeast winds of 20 to 30 knots develop Wed afternoon into Wed
evening. There is higher confidence that a strong low pressure
system approaching the region will bring strong gales to Lake
Superior, especially west. East to northeast gales to 45 knots are
expected across much of the west half with possible storm force
winds to 50 knots over far western Lake Superior late Wed night into
early Fri morning. Gale watch remains posted for most of Lake
Superior, except for far west where a storm watch has been posted.
Winds will drop blo gales by midday Friday as storm weakens over
the area.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Storm Watch from Thursday morning through late Thursday
night for MIZ001-003>007-013-014-084-085.
Winter Storm Watch from late Wednesday night through late
Thursday night for MIZ002-009>012.
Lake Superior...
Gale Watch from Thursday morning through late Thursday night for
LSZ245>248-265>267.
Gale Watch from late Wednesday night through Friday morning for
LSZ240>244-263-264.
Storm Watch from late Wednesday night through Friday morning for
LSZ162.
Lake Michigan...
Gale Watch from late Wednesday night through Thursday evening
for LMZ221-248-250.
&&
$$
SHORT TERM...Voss
LONG TERM...Rolfson
AVIATION...lg
MARINE...Voss
Area Forecast Discussion
National Weather Service Pendleton OR
735 PM PDT Tue Apr 9 2019
.SHORT TERM...Upper low over Montana continues to push clouds and
showers into southeast Washington and northeast Oregon this
evening. Radar indicating moderate showers over the Blues with
upslope flow. This will continue through the evening then diminish
overnight. Remainder of the forecast area is clear to partly
cloudy. A weak short wave evident on water vapor imagery will
bring mid and high level clouds overnight. High pressure building
across the region still producing gusty westerly winds. These will
decrease later tonight. Weak upper ridge over the area Wednesday
with partly to mostly cloudy skies. Another short wave will then
move through the Pacific northwest later in the day into Wed
night with additional rain and mountain snow. 94
&&
.PREV DISCUSSION... /issued 400 PM PDT Tue Apr 9 2019/
SHORT TERM...Tonight through Friday...An upper level trough
accompanied by a surface cold front pushed across the forecast
area last night and this morning, and the trough axis is
currently near the Idaho border. Showers remain behind the trough,
and snow levels have lowered to around 4500 feet. High pressure
building from the west has caused a tight pressure gradient to
develop and winds to increase. Wind Advisories were issued for the
Kittitas Valley, Simcoe Highlands, Eastern Columbia River Gorge,
the Oregon Lower Columbia Basin, and the Oregon Blue Mountain
Foothills. The strongest winds will likely occur between 1700-2000
when the HRRR has a 13mb difference between PDX-GEG. Believe the
MAV guidance has done a decent job with winds so far and is
indicating winds meeting advisory for these areas. Surprisingly,
despite all the recent rainfall, blowing dust was reported
between Hermiston and Boardman with gusts 35-40 mph this afternoon.
Multiple flood warnings remain in effect. For details, refer to
the HYDROLOGY section of this discussion.
The trough will exit the region tonight, allowing high pressure to
bring drier conditions overnight and into Wednesday morning with
the exception of widely scattered mountain showers. Showers will
increase in coverage during the afternoon and evening as a
shortwave slides south down the ridge and over the forecast area.
Although precipitation with this upcoming system will not be as
heavy as what has been observed the past 72 hours, there is a slow
moving front that will bring steady precipitation Wednesday night
through Thursday morning with QPF amounts of around 0.25-0.5 inch
over the mountains. Snow levels will be around 3500-4000 feet and
2-5 inches of snow will likely occur in the mountains...not enough
to meet advisory but one may be issued if future shifts anticipate
higher amounts. Precipitation will taper off Thursday night and
only isolated to scattered rain and mountain snow (snow levels
around 4500 feet) are forecast on Friday. Wister
LONG TERM...Friday night through Tuesday. Slight cooler than
normal will prevail through the extended period. Weak high pressure
will be over the area with mainly dry conditions Friday night into
Saturday. The next system will overspread the area Saturday
afternoon with a chance rain and mountain snow showers through
Sunday. Snow levels will be 4500-5500 feet on Saturday, but cooler
near 3500-4500 on Sunday. Another break on Monday between system
with the next trough to move through Monday night and Tuesday. These
systems will keep the cooler air over the area with snow levels 3500-
4500 feet. 93
AVIATION...00Z TAFS. Scattered showers mainly over ALW PDT PSC
through early evening. Ceilings 030-060. Otherwise gusty winds for
all Taf sites with 20-35kt this evening diminishing overnight. 94
HYDROLOGY...Moderate to major flooding is occurring on the Grande
Ronde and John Day Rivers with minor flooding on the Umatilla, Walla
Walla and North Fork John Day rivers. Even as the large rivers
crest, they will take several days to fall back below flood stage.
River flood warnings will continue. Reports of flooding along
smaller creeks including Canyon Creek, Camas Creek and others across
Union, Grant and Umatilla Counties. Smaller streams have been slow
to crest, but should start seeing those crest tonight, but in mean
time will continue areal flood warnings through next 24 hours. The
cooler temperatures expected overnight with mountain areas seeing
freezing temperatures will slow any snowmelt over the next few days
as well. 93
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 38 55 41 55 / 20 30 60 50
ALW 40 57 42 58 / 40 40 70 40
PSC 41 61 44 63 / 10 20 30 30
YKM 38 59 40 60 / 0 30 30 30
HRI 41 60 44 61 / 10 20 40 40
ELN 38 53 36 55 / 0 40 30 30
RDM 32 50 37 50 / 10 30 50 50
LGD 35 49 37 50 / 60 30 80 60
GCD 33 47 36 52 / 30 30 80 70
DLS 43 56 45 59 / 10 40 50 40
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 10 PM PDT this evening for ORZ041-044-507-
508-510.
WA...Wind Advisory until 10 PM PDT this evening for WAZ024-026-521.
&&
$$
94
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
819 PM EDT Tue Apr 9 2019
.UPDATE...
The latest RAP model places a deep low along the AL/GA line
this evening with mid level troughing and a cold front
stretching south over the eastern Gulf of Mexico. These
features slide across the state during tonight and over the
Atlantic coastal waters early Wed. As a result drier air
filters in...with model PWAT values dropping down to around
1.2 inches by daybreak...and southwesterly lower level flow
this evening shift to westerly then northwesterly Wed
morning.
Bands of showers with low clouds and gusty winds continue
to traverse the area but are expected to exit to the east
by midnight. A few areas of mostly light rain may drift in
from the Gulf during the rest of the night. Some lower
clouds will remains until after sunrise. While winds are
diminishing some this evening a high risk of rip currents
tonight will continue into Wed. Higher winds on the Gulf
this afternoon created some higher waves and seas that will
impact areas beaches and maintain the rip current threat.
Forecasts are generally on track but have made minor adjusts
in precipitation coverage for the next couple of hours or
so.
&&
.AVIATION...
10/00Z TAFs. Broken bands of SHRA with OCNL MVFR CIGS are
expected to clear the terminals by 05Z. Then prevailing BKN
VFR CIGS that slowly begin clearing AFT 16Z but with TEMPO
MVFR CIGS and LCL BR BTWN 09-14Z. SW winds diminish as they
shift to W then NW...gusty AFT 16Z at southern terminals.
&&
.MARINE...
The bulk of the showers have cleared the coastal waters
although there may be some periods light rain overnight.
Winds have diminished to around 15 knots or less. Seas may
be on the high side but below headline criteria.
&&
.Preliminary Point Temps/PoPs...
TPA 69 81 68 84 / 20 10 0 10
FMY 70 85 67 85 / 40 10 0 0
GIF 66 84 66 86 / 30 10 0 10
SRQ 69 80 66 84 / 20 10 0 0
BKV 64 82 61 87 / 20 10 0 10
SPG 71 80 70 85 / 20 10 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Wednesday evening for
Coastal Charlotte-Coastal Hillsborough-Coastal Lee-
Coastal Manatee-Coastal Sarasota-Pinellas.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...09/Rude
UPPER AIR...42/Norman
DECISION SUPPORT...69/Close