Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/19
Area Forecast Discussion
National Weather Service Columbia SC
1025 PM EDT Sun Mar 10 2019
.SYNOPSIS...
A weak cold front will move through the region tonight, with
scattered showers and a few thunderstorms expected ahead of it.
The front will stall south of the area into early next week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Radar and satellite imagery show extensive clouds over the area
along with a few light showers in the southeastern Midlands and
southern CSRA. Overnight a weak boundary will remain just south
of the area with a weak disturbance moving through the eastern
Midlands. Although the instability will be weak overnight there
is some potential for a few showers and possibly a thunderstorm
in the eastern Midlands. Toward daybreak the chance of showers
will end with clouds beginning to slowly diminish. Overnight
lows will range from the upper 40s north to the upper 50s
south.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Surface high pressure builds into the Southeast U.S. through
midweek. It will be a tranquil weather pattern with near normal
temperatures for mid March.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
High pressure moves off the East Coast on Thursday which allows
moisture and warmer temperatures to move back into the region.
An occluded surface low pressure system tracks into the Great
Lakes Thursday Night into Friday with a trailing cold front
slowly pushing into the Midlands and CSRA on Friday. Forecast
models do not depict significant instability with this frontal
passage, therefore will not mention thunderstorms in the
forecast.
High pressure rebuilds into the Southeast U.S. for next weekend
with dry conditions and near to slightly below normal
temperatures.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Observation trends support mainly VFR conditions. Low-level
drying has occurred in a westerly flow. The cold front will move
through the area tonight but radar trends indicate showers will
likely remain south of the area closer to deeper moisture. The
front will be just south of the area Monday. Satellite trends
indicate continued mid-level cloudiness will continue. Diminished
net radiational cooling because of this cloudiness plus some
boundary layer wind should help prevent fog during the early
morning hours. The GFS and NAM MOS plus HRRR and most SREF
members maintain VFR conditions through the 24-hour TAF period.
The GFS and NAM MOS support light west wind veering to northeast
as indicated by the GFS and NAM MOS.
EXTENDED AVIATION OUTLOOK...Dry high pressure is forecast to
dominate through Wednesday. A frontal system may bring flight
restrictions Thursday and Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
714 PM CDT Sun Mar 10 2019
.DISCUSSION...
Updated for the 00Z Aviation Discussion.
&&
.AVIATION...
Conditions expected to deteriorate through the evening,
especially across the coastal region, with IFR/LIFR conditions
developing between 00Z-06Z. LRD should take a big longer to lower
with lowering CIGs a bit more closer toward 06Z and beyond.
Improvements to VSBYs/CIGs expected around 15Z, however MVFR CIGs
will likely last through the rest of the TAF period. The exception
is LRD which may be able to break to VFR after 18Z. Winds will
generally be out of the E-SE 5-10 KTs.
&&
.PREV DISCUSSION... /Issued 322 PM CDT Sun Mar 10 2019/
SHORT TERM (Tonight through Monday Night)...
As of writing light showers/drizzle is ongoing across the Coastal
Plains and Victoria Crossroads as low level moisture increases
underneath the cap. A quasi-stationary boundary is currently
draped across central Texas and is progged to slowly track to the
south throughout the night. Ahead of this feature, fog is
expected to develop across much of the area as dewpoint
depressions will near 1 degree with condensation pressure deficits
ranging from 3 to 5 mb. We are currently seeing brief
improvements in visibilities along the coast but expected sea fog
to return this evening.
As the aforementioned shortwave moves to from NW to NE across the
northern part of the state late tonight, the weak boundary will
move south. How far south is the question. The NAM brings the
boundary into our northern tier of counties, while the RAP keeps
it across the Hill Country. Low level moisture will continue to
increase across the region, with the highest moisture axis located
along the Rio Grande. This boundary should be the focus for
scattered showers and potentially an isolated thunderstorm or two
on Monday. Our best chances for precip will be out west but
continued WAA across the Coastal Bend and Victoria Crossroads will
lead to sustained chances of scattered showers.
Onshore flow will keep us fairly warm over the next few nights
with lows 10-15 degrees above normal for this time of year. High
temps are expected to be a few degrees below normal tomorrow
across the east as mostly cloudy skies will hold temps down. We
may see some breaks in the clouds across the Brush Country
tomorrow, so they will warm into the low 80s.
LONG TERM (Tuesday through Saturday)...
The mid-level closed low that is currently off the coast of northern
California will finally be coming onshore Tuesday over the
Baja/northwestern Mexico area. This will provide a strong southwest
flow of Pacific moisture to the mid-levels. A mid-level shortwave
looks to pass just north of the area during the day. This coupled
with southeasterly onshore flow at the surface, will bring slight
chances for precip. While CAPE is extremely meager Tuesday, forecast
soundings show great SRH and shear which could bring some rumbles of
thunder to the area. By Tuesday night, the low pressure system lifts
in the desert southwest and looks to cross the TX Panhandle by late
Wednesday morning. This will push a Pacific cold front through the
area. With the added instability from the front, values of CAPE,
SRH, and shear values increase, so wouldn`t be surprised if some
storms could become strong to an isolated severe. Small hail and
gusty winds would be the main threats. PWATs also rise to near the
99th percentile, so any slow moving storms may produce a decent
amount of rain.
The mid-level low should lift quickly towards the Great Lakes region
by Thursday and precip will clear out of the area from west to east.
A second stronger cold front will finally push south through the
area late Wednesday night/early Thursday morning. The colder air
mass behind the front will bring high temps back down into the 60s
for the end of the week into the weekend. Northerly surface flow
looks to stay in place through the weekend. Long range models have
some discrepancies for precip chances for Friday into Saturday with
the GFS keeping the area dry vs the ECMWF trying to build moisture
over the area and the Gulf. Would think the GFS would be the more
correct solution, so have lowered the PoPs given by the blends but
retained some PoPs.
Marine...
We have seen improvements in visibilities along the coast this
afternoon, however sea fog will develop again this evening as warm
air continues to flow over the cooler shelf waters. Went ahead and
extended the Marine Dense Fog Advisory through 7 AM and it will
likely need extending after that. A weak to moderate southeast
flow will continue to kick off the work week. SCA conditions are
expected to develop across the coastal waters Tuesday evening into
Wednesday afternoon as a strong upper level system and associated
frontal boundary move across the region. A second cold front will
move across the waters on Thursday, turning winds to the north,
and SCA conditions are likely to develop in its wake, and persist
through Friday afternoon.
MARINE...
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 68 77 67 77 67 / 20 20 20 20 30
Victoria 66 76 65 76 65 / 30 30 30 30 40
Laredo 69 83 69 85 66 / 30 30 30 20 20
Alice 67 79 67 81 67 / 20 20 20 30 30
Rockport 66 74 66 73 65 / 20 20 20 20 30
Cotulla 65 77 65 81 61 / 30 40 40 30 40
Kingsville 69 79 69 79 68 / 20 20 20 20 30
Navy Corpus 69 75 69 73 67 / 20 20 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Dense Fog Advisory until 7 AM CDT Monday For the following
zones: Bays and Waterways from Baffin Bay to Port Aransas...
Bays and Waterways from Port Aransas to Port O`Connor...
Coastal waters from Baffin Bay to Port Aransas out 20 NM...
Coastal waters from Port Aransas to Matagorda Ship Channel
out 20 NM.
&&
$$
CB/85...AVIATION
Area Forecast Discussion
National Weather Service Grand Forks ND
643 PM CDT Sun Mar 10 2019
.UPDATE...
Issued at 641 PM CDT Sun Mar 10 2019
Added patchy fog to the forecast for the southwestern half of the
CWA as HRRR guidance is picking up on efficient radiational
cooling overnight. Otherwise, the forecast remains on track.
&&
.SHORT TERM...(This evening through Monday)
Issued at 343 PM CDT Sun Mar 10 2019
This evening, some mid level clouds will linger in the area,
especially over portions of northwest MN, as the primary longwave
upper trough propagates through the Dakotas and into MN. Expect
light winds and temperatures dropping into the single digits above
and below zero as surface high pressure builds through the region
tonight and early Monday. With Sunday`s sunshine melting the new
snow on paved surfaces and temperatures dropping to near saturation
levels overnight, can see potential for patchy fog. However, this
will not quite be an ideal radiational cooling scenario with the
lingering clouds and light winds, so will hold on adding to forecast
at this time. Look for warmer air to begin building in Monday as
warm air advection develops with southerly flow behind the surface
high.
.LONG TERM...(Monday night through Sunday)
Issued at 343 PM CDT Sun Mar 10 2019
Strong WAA and moisture advection through midweek, with strong
storm system possibly bringing myriad of impacts to the Northern
Plains Wednesday through Thursday night.
Monday night-Tuesday night: WAA results in above freezing/above
normal temperatures finally returning to our CWA by Tuesday, with
degree warming at surface dependent on clearing. This is complicated
by the influx of moisture within southerly flow and potential for
melting to add low level moisture, which could lead to persistent
fog or low stratus. Under ideal conditions potential is there for
upper 30s and lower 40s over parts of the southern RRV and northwest
MN on these days with overnight lows possibly hovering near or just
above freezing. Depth of saturation combined with some weak ascent
at times could result in drizzle or freezing drizzle particularly
Tuesday-Tuesday night.
Wednesday-Thursday night: Strong upper low still projected to move
towards the Northern Plains out Colorado, though trend has been
towards slowing this down and shifting it a little further south.
Consensus of models favors deformation axis extending up into our
CWA with current track, with high QPF across our south Wed night
into Thursday. Slower timing may favor majority of precip to occur
after air mass becomes colder decreasing potential for rain or
freezing rain, and increasing potential for heavy snow. In addition,
strong wind signal as LLJ on NW side of upper low supports wind
gusts 45 to 60 mph over our CWA (strongest on ND side of Red River
Valley). Older snow pack will likely be crusted over, however if
these strong winds align with snowfall then whiteout conditions would
be possible. At this range further track changes would shift impacts
away or further into our CWA, and impacts will be highly dependent
on track/timing.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 637 PM CDT Sun Mar 10 2019
VFR CIGS prevail west of the Red River this evening with MVFR to
upper IFR conditions for KBJI and KTVF. This will deteriorate
overnight as efficient radiational cooling and fresh snowfall
combine to facilitate low stratus and patchy fog development
across the region. West winds will remain under 10 knots through
the overnight hours and into Monday morning. Any patchy fog that
develops will lift gradually after sunrise.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Lynch
SHORT TERM...DJR
LONG TERM...BP
AVIATION...Lynch
Area Forecast Discussion
National Weather Service Green Bay WI
720 PM CDT Sun Mar 10 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 244 PM CDT Sun Mar 10 2019
The latest RAP analysis and satellite/radar imagery show a potent
area of low pressure exiting the region over northeast Ontario
early this afternoon. Visibilities continue to improve over
northern WI as light snowfall on the back edge of the system
diminishes. Back edge of the cloud shield, however, is just
starting to enter western WI. Some partial clearing appears
possible by late this afternoon, particularly in the downsloping
areas of northeast WI, as this cloud line draws closer to the
area. With the snow ending, forecast concerns generally revolve
around cloud trends and temps.
Tonight...Northwest winds will remain breezy tonight between the
departing low pressure system off to the east and high pressure
over the central Plains. Though the back edge of the cloud mass
will pass across the area this evening, models show low level
cold advection continuing through the night, with progged
soundings indicating a thin saturated layer getting trapped
beneath the subsidence inversion. Downsloping over northeast WI
could be enough to overcome this shallow layer of strato-cu, and
will continue to show mostly clear to partly cloudy skies
developing by late evening and overnight. Central and north-
central WI may not be as lucky, and will continue to show partly
to mostly cloudy skies there. Due to the breezy WNW winds and at
least scattered cloud cover, sided with the warmer temp guidance
for lows ranging from the mid teens to near 20 by Lake Michigan.
Monday...High pressure will continue to draw closer to the region
which should lead to a quieter day. Any lingering clouds over
central and north-central WI should retreat to the north during
the morning. But then with heat of the day, steepening low level
lapse rates should lead to scattered cu popping in the afternoon.
Temps will fall back slightly with highs ranging from the upper
20s to low 30s across most of the area.
.LONG TERM...Monday Night Through Sunday
Issued at 244 PM CDT Sun Mar 10 2019
The main concern in the extended portion of the forecast will be the
potential rainfall/flooding potential for the middle of the workweek
along with above normal temperatures.
Monday night through Tuesday: A surface ridge and increasing 500mb
heights will be in place through this time period, bringing an
extended break in the precipitation along with warmer temperatures.
In fact many places will warm to near normal by Tuesday afternoon.
Highs Monday will be around 30 while high temps warm to the mid and
upper 30s for Tuesday. Overnight lows will be chilly with lows
dropping down into the teens Sunday night and to the single digits
above and below zero for Monday night. Leaned toward the colder
guidance for Monday night with high pressure over the area, clear
skies and PWAT values around 25 percent of normal.
Wednesday through Thursday: The next southern stream piece of energy
is expected to eject out of the Four Corners region into the central
Plains Tuesday night into Wednesday morning. This would likely
lead to rapid cyclogenesis across the Oklahoma and Texas Panhandles
Wednesday morning. The low is then expected to lift northeastward,
reaching western or central WI late in the day Thursday. This would
keep most of the CWA in the warm sector, keeping the precipitation
mainly in the form of rain. There could be a brief period of mixed
precipitation early Tuesday evening, but this should quickly
transition to all rain for the rest of this time period. Still could
cause a brief period of hazardous travel. Of greatest concern will
be how much rain falls out of this system as it traverses the area.
It looks like there will be plenty of moisture for the system to
work with as the surface isobars remain wide open to Gulf moisture
through much of this time period.
PWAT values are progged to be around 1.0 to 1.5 inches for this time
period, which is roughly 200 - 250 percent of normal for this time
of year. A strong southerly LLJ is progged to develop ahead of this
system, which will allow moisture to quickly advect northward into
the CWA along with much warmer temperatures. Actually, most of the
models are pushing 850mb temperatures up to around the +6 to +10C
range Wednesday into Wednesday night. This would allow temperatures
to warm well above freezing through this time period with most
locations warming into the upper 40s and even pushing into the low
50s in a few locations. The combination of increasing dewpoint
temperatures (above freezing/mid to upper 30s) and warmer
temperatures will start melting some of the snow across the area;
however, this will take some time as the snowpack is fairly dense
and will take time to ripen to the point where rapid melt would take
place. The bigger concern will be largely focused on the potential
for an inch or so of rain to fall (GEM/GFS) on frozen ground and
across areas that may have poor drainage due to ice/snow clogging.
The latest 12Z model run of the EC has less QPF, closer to a half
inch or so. There will of course be some contribution from melting
snow, but the bigger issue will likely be any significant amount of
rain that falls, which may lead to at least localized flooding
concerns in areas that have poor drainage. The rain will likely
come in a couple of waves, the first would be Wednesday into
Wednesday night as waa/moisture advecting increase across the
area, leading to strong isentropic upglide ahead of an approaching
warm front. The warm front is expected to slide into/through the
area Wednesday night into Thursday morning, which would be the
most likely time for heavier rainfall and fog. A dry slot may end
the rainfall for a period during the day Thursday before the
upper- level system and surface low slide directly overhead,
leading to the next shot of rainfall.
Rest of the extended: Another cold front will pass through the area
ushering in colder air and a fairly deep upper-level trough for
Friday into Saturday. This will effectively put the brakes on any
snow melt issues and help to lock in any water making its way
through the snowpack. Otherwise, temperatures will fall back below
normal with highs only expected to reach into the upper 20s and low
30s for Friday into Saturday. As the colder air filters in, any
lingering precipitation, associated with the trough overhead, will
likely transition over to some light snow. Only minor snowfall
accumulation is expected at this time.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 717 PM CDT Sun Mar 10 2019
Low clouds have scoured out of most of the area, with just a
combination of sct-bkn low and middle clouds likely to linger
across the far north overnight. Winds will remain fairly strong
overnight, but some of the gustiness will diminish. Expect some
daytime convective cloudiness to develop Monday, but coverage will
be limited so primarily VFR conditions are anticipated.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Cooley
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1047 PM CDT Sun Mar 10 2019
.SHORT TERM...(This evening through Monday night)
Issued at 318 PM CDT Sun Mar 10 2019
Early afternoon satellite imagery together with RAP13 surface
analysis and 500mb heights showed and upper level shortwave trough
along the MN/Dakota border, with another trough upstream across
southern Canada. These two features will merge as they are forced
eastward by an upper level ridge racing in upstream. The subsidence
associated with this ridge will lead to a surface high pressure
system building over the Upper Midwest later tonight and tomorrow.
This subsidence can already be seen by the clouds dissipating this
afternoon over the Dakotas.
For that reason expect clear skies, but cooler temperatures to
continue tonight and tomorrow. Did increase highs above guidance
north of I-94 for tomorrow, since there should be full sun and light
winds which usually ends up warming the wooded areas more than the
snow-covered areas of western and southern Minnesota. Could see some
fog develop as early as Tuesday morning on the leading edge of the
cold air advection ahead of the next system.
.LONG TERM...(Tuesday through Sunday)
Issued at 318 PM CDT Sun Mar 10 2019
Forecast concern remains the midweek system which will bring
heavy rain some flooding concerns followed by cooler
temperatures, some snow and strong winds Thursday.
Southerly winds increase Tuesday as a weak short wave travels to
the north of the area. This should draw lower clouds north during
the day along with the chance of some light rain mainly in the
afternoon. We should see temperatures warm to the 35 to 40 degree
range with sunshine becoming less apparent.
Models continue trend of developing strong cyclogenesis over the
Colorado/Oklahoma panhandle region Wednesday morning and lifting
northeast to Iowa by THursday morning. Strong lift moves into the
area later Wednesday/Wednesday night as the upper trough
approaches and moisture lifts into the area. 12z NAEFS
standardized anomalies of PW`s continue the trend of 3 to 4
standard deviations above normal with at least 0.75 to 1 inch PWs
affecting the area during this period. This should generate some
higher QPF values during this period as the deformation axis moves
in. Localized flooding in urban areas and area streams/lowland
flooding can be expected if the 1 to 2 inch QPF is realized
Wednesday/Wednesday night. Fog will be an issue as well, with
higher dewpoints, rain and melting snow.
Deterministic model trends continue to lift the surface low to
the southeast of of Minnesota Thursday. We will likely see some
transition from rain to snow as the upper trough and surface
system exit the area. There could be some accumulating snow as
temperatures cool rapidly from west to east. into Thursday night.
Strong northwest winds will develop with 25 to 30 mph sustained
winds anticipated with gusts around 40 mph at least to the west
and south if models do verify current trend.
Following the storm, we see cooler temperatures and dry continue
through the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1047 PM CDT Sun Mar 10 2019
Only potential issue continues to be threat of fog overnight
beneath the surface ridge axis in central MN. The HRRR continues
to be pretty aggressive with fog development over NW MN, but is
limiting it`s expansion across central MN. Blend of hi-res models
continues to show fog developing into AXN tonight, so kept that
mention going, though the LAV is trending less and less bullish on
the fog there, so it`s certainly possible they see nothing at AXN.
Given recent model trends, feeling more confident in keeping fog
out at any other locations. Mainly clear skies are expected Monday,
though winds will switch to the south as the ridge axis works
east. Looks like low clouds really hold off on getting up here
until Tuesday morning.
KMSP...We will likely see a period of cross winds Monday
afternoon, but with speeds under 8 kts, they should be of minimal
impact.
/OUTLOOK FOR KMSP/
Tue...VFR early, then IFR/LIFR/-RA. Wind SSE 10-15 kt.
Wed...IFR/LIFR with RA. Wind ESE at 10-15 kt.
Thu...IFR with -SHRA becoming -SN late. Wind NE at 10 kt becoming
NW at 20G30 kt late.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...JRB
LONG TERM...DWE
AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
720 PM EDT Sun Mar 10 2019
.SHORT TERM...(This evening through Monday)
Issued at 417 PM EDT SUN MAR 10 2019
Water vapor imagery and RAP analysis show a weakening shortwave
lifting ne of the northern Great Lakes. Upstream, a shortwave is
tracking across MN toward northern WI with a second shortwave trof
extending from Hudson Bay to western ND. At the sfc, low pres is
located n of Georgian Bay. Rather tight pres gradient btwn this
994mb low and 1027mb high pres over the Plains is leading to
increasing winds across the fcst area this aftn with gusts now into
20-35mph range. Snow associated with the departing shortwave has
been diminishing and lifting ne today.
Shortwave now approaching northern WI should give a boost to the
lingering snow late aftn thru mid evening as it catches up to the
not yet departed deep moisture associated with the prior shortwave.
Model guidance over the last 24hrs, including hourly RAP/HRRR runs
since 12z, show an uptick in snow into the nw fcst area during the
late aftn/early evening and also into the eastern fcst area during
the evening in response to this shortwave. Given the rather vigorous
look of the approaching shortwave, have opted to buy into the
increase in snow this evening. Signal is stronger over the nw fcst
area due to the more pronounced upsloping under brisk westerly
winds. There are likely sufficient breaks in the ice cover on Lake
Superior to yield a weak lake enhanced component to the snow as well
as 850mb temps will be around -8 to -9C. With westerly winds gusting
to around 35mph or so, leading to areas of blsn/sharply reduced vis
in open areas and the expectation of an additional 1-4 inches of
snow accumulation, extended the winter wx advy for Keweenaw/northern
Houghton counties until midnight tonight. To the e, will let the
ongoing advy expire as scheduled at 21z. Expect an additional 1 to
perhaps as much as 3 inches of snow in that area tonight. Will need
to watch how snow intensity evolves over nw Upper MI in the coming
hrs. If a more substantial increase in snow occurs, may need to
issue a new advy over the e during the evening hrs.
Trailing shortwave trof currently extending from Hudson Bay to the
western Dakotas will reach the Upper Lakes Mon morning. While this
will provide some additional forcing late tonight/Mon morning,
departure of deeper moisture suggests there shouldn`t be too much
response to light LES that will be ongoing under a marginally cold
air mass (850mb temps around -14C) following the passage of the
other shortwave tonight. Lingering light w to nw flow LES will then
diminish/end from w to e on Mon as waa begins/drier air arrives.
.LONG TERM...(Monday night through Sunday)
Issued at 339 PM EDT SUN MAR 10 2019
With a quiet Tue, attention is on Tue night into Thu night when
warm, moist air surges into the region ahead of a strong low
pressure system. Ptype is troublesome Tue night as surface
temperatures start out below freezing as rain moves in, resulting in
some freezing rain, but temperatures will be warming so the threat
will not be overly persistent. Current forecast is for a glaze of
ice over portions of the central and east. Temperatures will top out
in upper 30s to mid 40s Wed and in the 40s Thu with lows Wed night
above freezing. Dew points will also be above freezing. Rain is
expected more often than not during the period, with potential for
0.75-1.50" of liquid, although some guidance does have up to 2" in
spots. Uncertain on exactly how much runoff into streams will occur,
but at this point expecting the snow pack to soak much of the precip
up. Certainly could see some issues with ponding on water on roads,
though.
Precip turns to snow Thu night and Fri as the rapidly weakening low
and another shot of upper level energy shifts across the area.
Plenty of uncertainty in how much snow falls, but not looking like
anything too significant at this point. Colder temps Fri into the
weekend will, for the most part, put a halt to the melt, leaving us
with even more liquid in the very compressed snow pack.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 714 PM EDT SUN MAR 10 2019
At KIWD, expect prevailing MVFR condiitons into Mon morning before
improving to VFR. At KCMX, expect conditions varying btwn LIFR
and VLIFR early this evening in snow and blsn, then improving to
MVFR overnight and to VFR Mon afternoon. At KSAW, MVFR conditions
should mostly prevail this evening, then generally VFR overnight
into Mon as -sn ends. At all terminals, wnw winds will be gusty
to 25-35kt thru early evening before slowly diminishing overnight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 417 PM EDT SUN MAR 10 2019
W to nw gales to 35-40kt will continue for much of the night over
the e half of Lake Superior in the wake of departing sfc low pres.
Winds will slowly diminish from w to e Mon, leading to a period of
lighter winds under 20kt Mon night/Tue. Winds will increase again
midweek, but gales are not anticipated until possibly late week in
the wake of low pres tracking ne across the northern Great Lakes.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory until midnight EDT tonight for MIZ001-
003.
Lake Superior...
Gale Warning until 6 AM EDT Monday for LSZ248>251-265>267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Titus
AVIATION...Voss
MARINE...Rolfson
Area Forecast Discussion
National Weather Service San Francisco Bay Area
845 PM PDT Sun Mar 10 2019
.SYNOPSIS...An upper level low moving south offshore will
continue to produce scattered showers across the southern portion
of our area through late evening. Dry conditions will return by
Monday, but slight rain chances return on Tuesday as a weak cold
front moves through the area. Most locations will see little to
no precipitation as the system passes on Tuesday. High pressure
will build over the West Coast for the remainder of the week and
into next weekend, resulting in a warming and drying trend.
&&
.DISCUSSION...As of 8:45 PM PDT Sunday...An upper low is currently
centered about 150 miles west-southwest of Monterey Bay and is
drifting slowly south. This upper low trigger widespread showers
and isolated thunderstorms across our area today. A thunderstorm
over the South Bay late this afternoon produce considerable small
hail in San Jose, enough hail to cover the ground in some areas.
Thunderstorm activity ended around sunset this evening and current
KMUX radar shows that shower activity is winding down as well.
Currently, showers are mostly confined to areas from southern
Santa Clara County into northern Monterey County. 00Z NAM and
latest HRRR indicate all shower activity will end by midnight as
the upper low continues to drift south and the airmass across our
area becomes more stable. Expect dry and seasonably cool weather
in all areas from late tonight through Monday.
Today`s precipitation may be the last our area sees for a while.
A system currently in the Gulf of Alaska is forecast to move to
the southeast and sweep across northern California on Tuesday.
However, the model trend as of late has been to track this system
farther inland and it now appears that little or no rain will fall
in our area on Tuesday. The primary impact of the Tuesday system
will be the brisk northwest winds that are expected to develop
after the mostly dry cold front sweeps through. Winds will
increase during the afternoon and remain gusty into the evening,
particularly near the ocean where gusts as high as 40 mph are
possible late in the afternoon and into the early evening hours.
The models are in agreement in maintaining dry conditions for the
remainder of the week and into next weekend. Temperatures will
start off about 5 degrees cooler than normal on Monday and Tuesday
but then gradually warm through the rest of the week as an upper
ridge slowly strengthens over California. By next weekend we could
see temperatures about 5 degrees warmer then normal with highs in
the lower to mid 70s.
&&
.AVIATION...As of 04:28 PM PST Sunday...For 00z tafs. VFR
prevailing with scattered showers into this evening. Have observed
several lightning strikes this afternoon in the Oakland area and
north of San Jose along with reports of small accumulating hail,
mainly in the East Bay. Isolated thunderstorms will remain
possible around the Bay Area over the next couple of hours before
diminishing. Therefore kept VCTS in the Bay Area tafs until 02z.
Cigs/vis may lower in thunderstorms and winds will become
variable. Cigs have generally been around 3,000-6,000 ft AGL and
are expected to improve overnight with mainly clear skies expected
by tomorrow. Winds to remain generally light through the period.
Vicinity of KSFO...VFR. Isolated thunderstorms to remain possible
until around 02z with showers in the vicinity until late tonight.
Winds may become more variable during passing thunderstorms/showers
along with lowering cigs/vis. Skies to gradually clear into
tomorrow morning along with light winds overnight.
SFO Bridge Approach...Similar to KSFO except more showers on
approach to the south.
Monterey Bay Terminals...VFR to brief MVFR possible under passing
showers. Shower activity possible through early this evening with
a stray thunderstorm possible. Light winds through the period with
skies clearing out tonight.
&&
.MARINE...As of 8:09 PM PDT Sunday...Building high pressure will
increase northerly winds across the coastal waters tonight and
through the coming days. Gale force gusts may be possible late
Tuesday. A longer period northwest swell will continue to move
through the waters tomorrow as a shorter period west swell
dissipates.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Rough Bar Advisory for SF Bar
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: AS
MARINE: AS
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Area Forecast Discussion
National Weather Service Reno NV
144 PM PDT Sun Mar 10 2019
.SYNOPSIS...
Expect a few snow showers along with gusty northeast winds into
this evening. A quiet weather day is forecast Monday, with a fast
moving cold front bringing strong northwest winds and a brief
period of light snow Tuesday afternoon. High pressure returns
starting Wednesday with lighter winds, gradually warming
temperatures, dry conditions lasting into early to mid next week.
&&
.DISCUSSION...
Through Monday...
Looking out the window it`s pretty obvious the airmass is quite
unstable. Bubbling cumulus that you can watch grow by just staring
at them for a few seconds. As such, snow showers will be the main
issue for the next 12 hours or so. No major forecast changes.
* Scattered mainly instability driven snow and pellet showers are
expected through early evening over much of the region. HRRR
showing CAPE values 400-600 which is supporting these westward
moving cells. Any particularly heavy snow showers could put down
a very brief accumulation, but most paved surfaces are warm
enough to melt any new snow. A few cells showing reflectivity
above 40dBz so some thunder/lightning can`t be ruled out. Any
showers persisting after the now later sunset could have more of
a road impact but coverage looks isolated.
* Main concern area is the Eastern Sierra of Mono County into
Mineral County in Nevada. Here there is the instability plus
some synoptic forcing for banded snow lasting well into the
evening and perhaps the overnight hours. HRRR showing this
scenario last several runs. This would yield more accumulation
and travel impact post sunset for highways such as 395, 95, and
6. Even at lower elevations a light accumulation is possible.
* Monday still looks quiet with (very) shortwave ridging
overspreading the region ahead of Tuesday trough/front. GFS has
a few light snow showers lingering Monday in the Eastern Sierra
otherwise dry with light winds are expected.
-Chris
Tuesday Onward...
No significant changes were made to the forecast from Tuesday
through next weekend.
For Tuesday`s weak trough passage, the overall timing looks similar
with areas of light snow starting in the morning for areas north of
Susanville-Gerlach, then pushing southward across I-80 to near US-50
during the afternoon. After sunset, the majority of the snow is
likely to be south of US-50 before diminishing by midnight. We`re
expecting less than 1" for most areas, with maybe a couple inches in
parts of northeast CA/Tahoe and higher elevations of west central
NV. Minimal travel impacts are likely as most of the snow will
fall during the daytime hours, then after the snow ends, brisk
northwest winds should dry out most paved surfaces before road
temperatures drop below freezing late Tuesday night. If any icy
patches develop, this is more likely late Tuesday night into early
Wednesday morning in areas south of US-50 where the window for
drying will be shorter, and for the northeast CA/Tahoe regions
where road temperatures will cool off more quickly after sunset.
For the remainder of the week, we are expecting dry conditions as
high pressure develops near the west coast and builds inland.
Wednesday will remain brisk and chilly with highs only in the lower-
mid 40s for lower elevations and 30s near the Sierra, about 10-15
degrees below average. Then we`re expecting a steady warming trend
starting Thursday with light winds each day, leading to some
valley inversions and limited mixing especially in the morning.
By next weekend, temperatures are likely to reach or surpass 60
degrees in lower elevations, although some of the warmer scenarios
bring highs close to 60 as soon as Friday, and above 65 degrees by
Sunday. For areas near the Sierra, highs are likely to reach or
exceed 50 degrees by next weekend. MJD
&&
.AVIATION...
Weakening low pressure dropping along the California coastline
combined with an unstable airmass will help generate scattered
snow showers into this evening across portions of the Sierra and
Western Nevada. Quiet weather is expected Monday before a fast
moving cold front briefing strong NW winds and a brief period of
light snow Tuesday afternoon.
For RNO,CXP: Latest HRRR simulations show continued risk of MVFR
periods in snow showers through about 3z/Mon. Quieting down
afterward as instability wanes. Generally the warm pavement in
mid-March will melt most snow, but if we were to have a heavy snow
shower with visibility below 1SM then can`t rule out a very temporary
light accumulation under a half-inch.
For TVL,TRK: Latest HRRR simulations show continued risk of MVFR
periods in snow showers through about 5z/Mon. Quieting down
afterward as instability wanes. Generally the warm pavement in
mid-March will melt most snow, but if we were to have a heavy snow
shower with visibility below 1SM then can`t rule out a very temporary
light accumulation. Any snow after sunset also has better chance
of accumulating. Up to one inch possible.
For MMH: Unlike this morning, MMH is probably more in the focus
for snow late this afternoon into the evening. Best forcing and
instability are projected for eastern Sierra during this timeframe.
Periods of MVFR to IFR snow between 0z and 10z/Mon from latest
HRRR. With falling temps some runway accumulations are possible
during this timeframe. 9/10 chance of 1", 4/10 chance of 3"+.
-Chris
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Sacramento CA
204 PM PDT Sun Mar 10 2019
.SYNOPSIS...
Scattered showers today, mainly over the foothills and mountains,
with a slight chance of an afternoon thunderstorm. Dry Monday,
then a weak storm moves through Tuesday bringing light precip to
portions of the forecast area. Dry weather follows into the
weekend with some breezy north to east wind Wednesday into
Thursday.
&&
.DISCUSSION...
Closed low off the coast centered near 37N and 124W will stay
off the coast and drift southward along the coast tonight.
Scattered showers will be popping up this afternoon, mainly over
the mountains with some isolated activity for the valley. Snow
levels are around 3500 to 4500 feet. Models showing light amounts
of snow accumulation over the northern Sierra into the evening
before ending. Afternoon instability is indicated in the models
with the best chances over the motherlode and places west of the
motherlode into the valley and Delta. HRRR indicates some possible
thunderstorms late afternoon to early evening in the Delta and
over the motherlode.
Shower threat ends tonight with drier weather Monday as interior
NorCal comes under short wave ridging. Ridge axis shifts through
Monday night followed by another short wave trough for Tuesday.
Overall precip amounts with this system look light, generally
below quarter of an inch for the mountains and probably just
hundredths of an inch accumulating for parts of the valley. Snow
levels will generally be in the 3500 to 4500 foot range.
Breezy northerly winds will set up behind the weak system Tuesday
night into Wednesday and a ridge of high pressure starts to build
over the west coast. Warmer temperatures are expected this week
with highs in the 60s for the valley and 40s for the mountains
after chilly morning starts.
&&
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)
Persistent high pressure expected throughout the extended period,
bringing dry conditions and warming temperatures. The upper level
ridge axis will shift east and center over the Western US Thursday
through the weekend. Winds will calm Thursday as surface pressure
gradients will relax. Temperatures will warm slightly every day.
Models continue to trend warmer with the temperatures, especially
over the weekend. Temperatures could top near or in the 70s for
most Valley locations this weekend. HEC
&&
.AVIATION...
Mainly VFR conditions expected except periods of MVFR/IFR
conditions in rain showers today. Showers ending after 00z Monday
Sacramento valley and after about 03z Monday northern San Joaquin
valley. Winds generally northerly less than 10 knots TAF sites in
the valley with gusts to 25 knots over the higher elevations after
00z.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$