Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/25/17
Area Forecast Discussion
National Weather Service Bismarck ND
941 PM CDT Fri Mar 24 2017
.UPDATE...
Issued at 937 PM CDT Fri Mar 24 2017
The area of stratus is not expanding westward as fast as earlier
thought so updated the cloud/sky forecast to maintain clear skies
a bit longer central tonight. The fog is also slow to develop but
starting to see temperature and dewpoint spreads close to
saturation at many locations and with an upslope component in the
windflow believe its juts a matter of time tonight. Delayed the
fog generally until after midnight.
UPDATE Issued at 635 PM CDT Fri Mar 24 2017
Am concerned about stratus area across the James River Valley
north through the Devils Lake Basin which appears to be expanding
westward in broad low level easterly flow. Expanded the clouds a
bit more into Bismarck and Minot tonight. Otherwise current
forecast looks ok.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 310 PM CDT Fri Mar 24 2017
A progressive pattern both in the short and long term period will
result in several fast moving systems with chances for precipitation
nearly every other day.
The latest suite of satellite imagery shows a mostly clear sky
across western and central ND this afternoon, with some cumulus
sprouting up in western ND. Webcams indicate shallow fair weather
cumulus, and this should be the extent of it as a mid/upper level
ridge and associated subsidence aloft continues to propagate
through this afternoon. By tonight, the ridge shifts east with a
southwest flow and low level warm air advection ensuing. With
increased vertical motion, expect an increase in mid/high clouds
per GFS 700-300mb RH field, mainly in the west and northern portions.
Latest HRRR visibility forecast maintains the development of fog
mainly along and east of the Missouri River tonight, especially
where we have the ongoing snowpack in the north central. However,
if clouds become thick enough overnight across the north, the fog
would likely be tempered a bit and reside farther south and east
from our current gridded forecast.
Current water vapor shows a shortwave trough along the northwest
coast with several lead shortwaves set to begin moving into
southwest ND early Saturday. These shortwaves will then move from
southwest to northeast throughout the day Saturday. At the surface,
low pressure forms in eastern Wyoming early Saturday morning and
shifts across southern South Dakota Saturday afternoon and evening.
An inverted surface trough from this surface low reaches into
western ND Saturday, which links up with a cold front sweeping
through central Saskatchewan. This cold front weakly extends into
north central ND, with a surface convergence setting up from
southwest to north central by afternoon. Thus will continue with a
chance for rain in the afternoon southwest through north central ND.
Afternoon highs will range from around 40F Turtle Mountains to
lower 60s southwest.
.LONG TERM...(Saturday night through Friday)
Issued at 310 PM CDT Fri Mar 24 2017
Chances for precipitation continue Saturday night north central/Turtle
Mountains and into south central ND as the convergence boundary
via the inverted surface trough to our south, and the Canadian
cold front to our north, propagate east. NAM BUFKIT soundings
sampled at Minot/Rolla/Devils Lake/Carrington/and Jamestown show
surface temperatures just above freezing late Saturday night,
with the exception of a couple hours before sunrise Sunday. That
being said, this leaves a small window of opportunity for light
freezing rain, but areal coverage this forecast cycle has shrunk
quite a bit from previous. At this point, would expect patchy/light
freezing rain from the Turtle Mountains into the northern James
River Valley, but not enough confidence to warrant advisory
criteria being met at this time. Future shifts can re-evaluate
this potential for any changes. Elsewhere, expect a high chance to
likely pops for rainshowers Saturday night through Sunday morning.
Although the probability for precipitation becomes less during
the afternoon, expect additional showers to develop as the main
mid/upper level shortwave slides through.
Beyond Sunday, expect a series of transitory ridges/troughs to
slip by with periodic chances for rain/snow at night and
rainshowers during the day. Nothing significant in terms of
precipitation amounts or a long duration event. Right now, expect
dry weather Monday into Tuesday morning, then chances for
precipiation increase from west to east Tuesday afternoon through
Wednesday. Thursday appears dry with the next system possible by
Friday into Saturday per GFS. The ECMWF keeps this system to our
south. High temperatures are forecast to remain above normal next
week with highs mostly ranging between 45F and 55F west and
central, and some 60s expected across the southwest.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 630 PM CDT Fri Mar 24 2017
Hazards to aviation will be areas of fog expected to initially
develop over the snow covered areas of north central North Dakota
this evening then expand south and east. Also stratus across east
central North Dakota will expand west to a KMOT-KBIS line late
this evening or early Saturday morning. IFR-LIFR expected KMOT
with MVFR to IFR at KBIS-KJMS. Some Wind shear possible KISN-
KMOT-KDIK 09-15z.
&&
.HYDROLOGY...
Issued at 310 PM CDT Fri Mar 24 2017
The continuation of a relatively benign spring melt season continues
as the spring melt is now upon the Souris (Mouse) River basin.
Thus far, minor flood stage has been reached only at the Souris
River below Lake Darling forecast point, but minor flooding is
expected to spread as snow melt in Canada initiates runoff and the
melt rate in North Dakota hits its stride over the coming days.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...KS
AVIATION...JJS
HYDROLOGY...JJS
Area Forecast Discussion
National Weather Service Taunton MA
1030 PM EDT Fri Mar 24 2017
.SYNOPSIS...
High pressure moves farther offshore tonight, bringing a
southwest flow of milder air to Southern New England. A cold
front will push south across the region Saturday. The front
will stall Saturday night, then will try to push northward
Sunday and Monday. Periods of light rain will fall Saturday,
then a mix of wintry weather will develop Sunday night into
early Monday. Rain may fall heavily at times later Monday as low
pressure passes across the region, then continues into Tuesday
ahead of an approaching cold front. Colder air lags Wednesday
into Thursday with breezy NW winds. Another chance for disturbed
weather Friday into the weekend given the continued active
weather pattern.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1030 PM Update...
Slowed the return of rainfall chances a bit more, based on
latest regional radar data and HRRR guidance. Will make further
tweaks to timing, as needed overnight.
Temperatures should remain nearly steady or slowly rise
overnight with a persistent southwest wind and abundant clouds.
Major theme of the forecast remains on track.
735 PM Update...
Precip associated with warm front has pushed NE into central
Maine and NH as seen on latest NE regional 88D radar imagery.
Based on this and increasing cloud bases, have updated to remove
mention of precip through around midnight. Will start to see
band of light rain shift S after midnight as front begins its
southward return. Light SW winds will also begin to shift to W
across N Mass as well. Will still see gusty SW winds through
this evening along the S coast, but those will start to diminish
as the pres gradient relaxes.
With the front and colder air behind it remaining N of the
region through most of the night, have updated temps/dewpts
to reflect current trends. Readings should bottom out in the
35-40 degree range.
Have updated remainder of forecast to bring conditions current
and incorporated trends through the remainder of the overnight.
Previous Discussion...
Upper level jet will push north of New England overnight,
carrying a wave of low pressure across Quebec. This will in turn
move the front south as a cold front after midnight. Low level
convergence may generate light showers that reach Northern Mass
by morning, but otherwise expect little/no precipitation in
Southern New England tonight due to southwest flow and no low
level forcing.
The mild flow of air will keep temperatures from falling much.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Saturday...
Cold front sweeps across the region first thing in the morning.
High pressure building in behind the front will turn winds from
the north Saturday morning and from the northeast in the
afternoon.
The upper jet referenced earlier will be to our northeast
Saturday with our area under the right entrance region. This may
maintain upper venting over/near the front while precipitable
water values along/south of the front remain at 0.75 to 1.0
inches, which is well above normal for mid-late March...the 90
pct exceed value is about 0.86. This should be enough to support
a chance of light rain, along and a little behind the front.
This rain shifts south of New England toward evening.
With clouds and potential light rain, expect temps to climb just
a little, with max values in the 40s.
Saturday night...
High pressure from Canada builds south into New England and
brings colder air. Expect dry weather most of the night. Dew
points will not fall as much as with most highs because our low
level flow will be out of the east-northeast, more of a marine
flow. Expect these dew points to be in the mid 20s to around 30.
As such, we expect min temps to be in the upper 20s to mid 30s.
With the ridge building in as it shifts toward the Maritimes,
the models show a developing cold air damming signature Saturday
night. This suggests the low level cold air will become
establish in advance of the next weather system.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Highlights...
* A period of wintry precip is possible Sunday night into Monday
morning
* Unsettled weather pattern will continue into Wednesday
* Improving conditions during the later half of next week
Overview...
Confidence with the overall pattern across the northeast U.S.
appears continues to improve, but still issues with details in
timing of weather systems as well as thermal pattern especially
this weekend into early next week based on 12Z model suite and
ensembles.
Active pattern continues for the region with split flow aloft
and several shortwaves ejecting across the lower 48 from the
Pacific. Model guidances continues to signal the deamplification
of H5 cutoff low over the midwest, becoming an open wave as it
moves across the region in the steering flow late this weekend
into early next week. With confluent flow aloft, high pressure
persists over northern New England keeping cool surface
temperatures which will result in a wintry mix of precip at
times late this weekend into early next week. A second wave
will follow a similar path from the Plains towards the northeast
before meshing or partially interacting with the northern jet
stream on Tuesday. This will result in another system for New
England Tues/Wed with high pressure to follow.
Details...
Sunday...Moderate confidence.
A stalled front along the mid Atlantic coast will try to work
northward as high pressure ridge shifts SE into the Gulf of
Maine. Winds aloft are mainly SW, which will allow some low
level moisture well ahead of low pressure over the midwest to
work slowly N during the day as ridge will shift slowly E.
Marginal thermal fields and good cold air damming pattern
remains across the region, which will lead to patchy mixed
rain, freezing rain and/or sleet across the interior for early
Sunday, but they are shallow so temps should rise above freezing
during the morning, However, some sleet/freezing rain may
linger through midday across the higher terrain. Temps will
recover to the upper 30s to around 40 well inland, to the lower
40s elsewhere thanks to low level onshore flow off the milder
ocean.
Sunday night through Monday night...Moderate confidence.
Stalled front to the S tries to shift back N as a warm front
late Sunday-Monday, while surface low pressure works toward the
Great Lakes. Good overrunning works across the region, with
H85-H7 temps rising to +5C to +6C during this timeframe.
Shallow low level cold air damming remains in place, though,
with temps falling the upper 20s to around freezing. This will
cause mixed precipitation to develop during the nighttime hours
both nights. Looks like the best shot for widespread light
sleet and/or freezing rain will occur Sunday night into early
Monday morning. Noting mainly freezing rain signatures on both
NAM and GFS BUFKIT soundings, can`t rule out sleet especially
across the higher terrain of the E slopes of the Berkshires and
northern Worcester hills. At this point, could see up to 0.1
inches ice accretion, but this remains dependent upon how long
the cold air remains in place as well as the low pressure
passage and the QPF amounts that move across.
Low pressure passes across the region during Monday afternoon/
evening so expect good shot of precip to work across. This will
coincide with increased PWAT values of around an inch and, along
with continued confluent pattern, could see around 0.5 to 0.7
inches QPF which will move across when temps should be above
freezing. Also noting some marginal instability across N
CT/RI/SE Mass moving across Monday afternoon, with total totals
around 50 and TQ values in the upper teens. At this point, with
E-SE low level flow continuing, not expecting any thunder at
this time.
Precip should slowly taper off as low moves offshore Monday
evening. With the marginal thermal pattern remaining in place,
could see another round of light freezing rain, though looks to
be primarily across the higher terrain of N central Mass after
midnight through the early morning hours of Tue.
Tuesday into Wednesday...
Continued risk of freezing rain early on, if not at a minimum a
cold rain is forecast. Associated deeper mid to upper level low
over the S Hudson Bay region with a cascading, deamplifying
open wave trough through the S-stream yields an elongated area
of low pressure across the E CONUS with secondary low
development across the Mid-Atlantic. Initial over-running moist
ascent transitioning to frontogenetical, synoptic forcing ahead
of a sweeping cold front. However the colder air lags. So
altogether, PoP chances through Tuesday night, clearing into
Wednesday. A cool, damp day especially for N/NE MA initially,
gradually warming, with a decent slug of rain. The cold air
lagging along with clearing Wednesday, may end up mild as
conditions dry.
Thursday...
High pressure in control however the crux of the colder airmass
is drawn S to the E of New England as the early to mid week low
over the Hudson Bay region of Canada undergoes deeper
cyclogenesis across the N Atlantic. Given a mix of sun and
clouds, and that being a late March sun, leaning mild with more
seasonable conditions. Cold air advection proceeding in the low
levels along with an enhancement of flow aloft, expect some
gusty NW winds the the boundary layer mixing up to around H85.
Friday into the weekend...
Confluence within the mid to upper levels of N/S streams across
the NE CONUS continues. Any closed lows emerging out of the SW
CONUS undergo deamplification. Scenario for continued over-
running setups to which the thermal profiles across the region
require scrutiny. Conflicting signals of low pressure evolution
associated with weak wave impulses neighbored against high
pressure out of Canada. A lot can change and thus a low
confidence forecast. Only confidence is that we`ll continue to
see an active weather pattern into the long term period.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday Night/...Moderate confidence.
Tonight...
Mainly VFR, with patchy MVFR CIGS across central and N Mass.
Gusty SW winds will continue to diminish. Patchy -RA may push S
out of NH/VT across N/Central Mass after 06Z.
Saturday...
A cold front moves north to south across the region during the
morning. An area of light rain may develop, with cigs and vsbys
lowering to MVFR. Winds shift from the north in the morning and
northeast during afternoon/evening.
Saturday night...
Mainly VFR as high pressure builds from the north. MVFR will
lurk to our southwest, preparing to move north again. East flow
through the night.
KBOS TAF...High confidence in TAF.
KBDL TAF...High confidence in TAF.
Outlook /Sunday through Wednesday/...
Sunday-Sunday night...Low to moderate confidence.
VFR CIGS/VSBYS early Sunday. CIGS lower to MVFR-IFR mainly
across the interior by midday Sunday and continue Sunday night.
Mainly VFR VSBYS Sun, then lower to MVFR-IFR Sun night in rain
and patchy fog. Areas of -FZRA/-PL develop across the interior
Sun night, especially across the higher terrain.
Monday-Monday night...Low to moderate confidence.
Any leftover -FZRA/-PL Monday morning will end across higher
terrain. Otherwise MVFR-IFR CIGS in light rain. VSBYS should be
mainly VFR, but may see local MVFR at times. Low chance for
-FZRA Mon night across higher terrain of N Central Mass, mainly
N of Route 2.
Tuesday...Low confidence.
MVFR-IFR mix with -RA/RA, low risk FZRA early over N/NE MA. N/E
winds turning out of the N/W.
Wednesday...Moderate confidence.
Improving. Cigs lifting VFR. N/W winds continue.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday Night/...
Converted the Gale Warnings to Small Craft Advisories for the
rest of tonight. Expecting more Small Craft Advisories to be
able to be dropped later tonight as SW wind gusts diminish.
Tonight...High confidence.
SW winds gusting 25-30 knots early will diminish overnight, and
become west toward morning. Rough seas linger across the outer
coastal waters, and ocean-exposed south coastal sounds.
Saturday...High confidence.
W winds shift to N in the morning and early afternoon as a cold
front moves north to south. Winds then shift from the northeast
by afternoon as high pressure moves in from Quebec. Winds will
be less than 25 knots through the day. Seas will linger at 5
feet on the southern outer waters and parts of RI Sound much of
the day. Small Craft Advisory will be needed where seas linger
near 5 feet.
Saturday night...Moderate-High confidence.
Northeast winds turn from due east overnight. Speeds remain
below 20 knots through the night. Seas will remain less than 5
feet through the night.
Outlook /Sunday through Wednesday/...
Sunday-Sunday night...Moderate confidence.
E-SE winds will increase especially on the southern outer
waters. Expect gusts up to around 25 kt on the open waters. Seas
may reach 5 ft on the outer waters S of RI briefly Sunday
afternoon/evening. Visibility reductions in rain and patchy fog
will develop Sun afternoon and continue Sun night.
Monday-Monday night...Low to moderate confidence.
E-SE winds continue. Winds gust to around 25 kt mainly over the
eastern waters as seas build to around 5 ft. May need small
craft headlines there. Local visibility restrictions continue in
rain and patchy fog mainly during Monday.
Tuesday through Wednesday...Low to moderate confidence.
Rain continues across the waters with E winds. Could see some
visibility restrictions ahead of a cold front sweeping the
region late into Wednesday morning. Behind the front winds
become more westerly and could see some gusts. Waves over 5 feet
possible on the outer waters.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ232>234-
250.
Small Craft Advisory until midnight EDT tonight for ANZ231-251.
Small Craft Advisory until 6 AM EDT Saturday for ANZ235-237.
Small Craft Advisory until 8 PM EDT Saturday for ANZ254>256.
&&
$$
SYNOPSIS...WTB/Sipprell/EVT
NEAR TERM...WTB/Belk/EVT
SHORT TERM...WTB
LONG TERM...Sipprell/EVT
AVIATION...WTB/Sipprell/EVT
MARINE...WTB/Belk/Sipprell/EVT
Area Forecast Discussion
National Weather Service Caribou ME
925 PM EDT Fri Mar 24 2017
.SYNOPSIS...
A cold front will cross the area tonight. High pressure will build
down from central Canada Saturday into Saturday night and crest over
the region on Sunday. Low pressure will approach from the west
Sunday night into Monday.
&&
.NEAR TERM /THROUGH SATURDAY/...
9:25 PM...Moisture continues to stream across the area this
evening as a weak wave of low pressure tracks across the region
and a cold front is expected to drop south across the CWA
overnight. Snow will continue across the southern half of the
CWA, perhaps mixed with a little rain at times along the coast.
A little band of light snow developed across far northern Maine
over the past 1 to 2 hours and this should not amount to more
than a dusting to a few tenths of an inch. Accumulations have
mostly been in the 1 to 2 inch range across the southern half of
the CWA, and up to another inch of snow is expected before most
of the precipitation pushes offshore with the cold front after
midnight. Made some tweaks to forecast based mostly on the
latest observations and radar trends. The near term models are
not capturing the snow across far northern areas well this
evening, but are doing a much better job with the precipitation
Downeast.
Previous discussion...
18Z sfc analysis showed warm front lift across the region
w/radar showing activity filling back in across central and
downeast areas. Activity was in the form of light snow w/very
light accumulations(< 1 inch) due to melting. Some sites across
northern Maine such as MLT and HUL seeing some light snow.
Temps across the central and downeast areas were tempered down a
bit today given the snow averaging the lower 30s. Temps should
warm a bit was precip lightens up. Further n, temps rose into
the upper 20s and lower 30s w/little or no snow. 12Z UA showed a
nice jet streak in the 850-700 mb layer helping to ignite the
first batch of snow. The 12Z run of the NAM and the latest HRRR
show this batch well and pushing as the warm front lifts n.
The next wave of snow will come this evening mainly affecting
the Downeast and southern Maine region. Kept 60-80% across
central and downeast areas this evening and then drop them off
sharply by midnight w/the loss of mid level forcing. Total
accumulations expected are in the 1-2 inch range w/highest
amounts across interior Downeast. Partial clearing later tonight
as the cold front pushes across the region. Overnight temps
forecast to be in the upper 20s across the n and w while central
and downeast will see low/mid 20s.
High pres is expected to slide east from central Canada on
Saturday. There should be a good deal of sunshine w/a nw breeze
of 10-15 mph. Despite the breeze, daytime temps should respond
to the March sunshine. Decided to go above the guidance on
Saturday maxes showing well into the 30s across n and w and
low to mid 40s central and downeast areas.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
High pressure building down from Canada will bring a starlit and
cold night Saturday night followed by a mostly sunny morning Sunday
morning. High pressure will crest over the region on Sunday bringing
tranquil conditions. Skies will begin mostly sunny. Some high
cloudiness streaming over the top of the ridge will dim sunshine a
bit during the afternoon. Clouds will then increase Sunday night
ahead of low pressure approaching from the west. Some light snow may
begin to push into western and Downeast areas toward morning Monday
morning. Light snow is likely across the area on Monday as a weak
upper level shortwave and disorganized surface low moves through.
Precipitation amount`s looks like with only an inch or two of snow
expected over inland locations. With temperatures rising well into
the 30s, road surfaces should just be wet during the midday and
afternoon on Monday.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
One weak wave of low pressure will slide by to the east Monday night
with any snow tapering off to flurries and skies remaining cloudy
with low clouds lingering. Another weak upper level shortwave and
surface low will approach on Tuesday. Another round of light snow is
likely late Tuesday into Tuesday night. Boundary layer temperatures
will be warmer with this second system and snow will likely change
to rain across Downeast areas Tuesday night. Precipitation will end
Downeast on Wednesday. However, snow may linger across the north
into Wednesday afternoon. An inverted trough from developing low
pressure south of Nova Scotia will likely extend across the north
and combine with an upper low moving over the region to extend snow
or a mix of snow and rain across the north. The low will continue
east Wednesday night into Thursday as gusty northwest winds follow.
Flurries and lingering clouds are likely north with some clearing
Downeast. High pressure will build over the area Thursday night
bringing clearing and lighter winds. Another weak shortwave may
approach with clouds and some light precipitation on Friday.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR to low end VFR late this evening for FVE, CAR,
PQI, and HUL. IFR and LIFR conditions in snow at BGR, and rain
and snow at BHB. Conditions at all sites improving to VFR from
north to south overnight with VFR conditions Saturday.
SHORT TERM: VFR conditions in mostly clear skies are expected
Saturday night through Sunday. Conditions may lower to MVFR
Downeast late Sunday night and remain VFR across the north.
Mainly IFR conditions in low clouds are then likely Monday into
Tuesday.
&&
.MARINE...
NEAR TERM: A small craft advisory remains in effect for the
coastal and intra-coastal waters. The wind will begin to
subside late this evening falling below SCA by around midnight.
Seas will remain above 5 FT until around 8 AM tomorrow across
the coastal waters. The wind and Seas will continue to subside
Saturday as higher pressure builds across the waters.
SHORT TERM: Winds will be below SCA Saturday
night into Monday morning as high pressure crests over the
waters. A SCA may be needed late Monday into Monday night for
east southeast winds ahead of approaching low pressure. Winds
may diminish a bit on Tuesday as weak low pressure south of Nova
Scotia moves away and another small low begins to approach from
the Appalachians.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ050>052.
&&
$$
Near Term...CB/Norton
Short Term...Bloomer
Long Term...Bloomer
Aviation...CB/Norton/Bloomer
Marine...CB/Norton/Bloomer
Area Forecast Discussion
National Weather Service Dodge City KS
641 PM CDT Fri Mar 24 2017
...Updated Aviation Section...
.SHORT TERM...(This evening through Saturday)
Issued at 345 PM CDT Fri Mar 24 2017
A strong upper level low pressure system was over the northeast
Texas Panhandle early this afternoon. This system is nearly
vertically stacked with the surface low and has been moving slowly
southeast this afternoon. Colder air was plunging south across the
western High Plains behind the low. An occluded front associated
with the surface low was pushing south along a Dighton-Garden
City-Hugoton line. Gusty north winds had developed along and west
of the front. Given the slow eastward movement of the upper
system, the strongest north winds had remained west of the
Colorado border this morning. Winds over eastern Colorado have
subsided somewhat to the point where warning criteria winds are no
longer a threat. As a result, the high wind warning that was in
effect for today has been cancelled. Radar mosaic was showing
scattered light showers or sprinkles developing along and
southeast of the front. Instability across this area is fairly
weak with the SPC Mesoanalysis showing SBCAPE values generally
less than 250 j/kg so the threat for thunder should be minimal.
Mesoscale models such as the HRRR, Nested NAM and RAP show the
precipitation developing and gradually shifting eastward through
the rest of this afternoon and evening. Have adjusted the WX/POP
grids with chance/slight chance pops into this evening before
precipitation chances end.
Gusty north winds behind the front will linger into the evening
hours as a tight pressure gradient moves through the area. Winds
will diminish later tonight as the gradient relaxes and ridge of
surface high pressure moves into the far west. Stratus behind the
front will also linger for much of the night but should be clearing
out later tonight as atmospheric subsidence increases.
Saturday is shaping up to be fairly pleasant with temperatures
expected to top out in the 60s. Northwest winds at 10-20 mph in
the morning will diminish during the afternoon as a high pressure
ridge at the surface moves through.
.LONG TERM...(Saturday night through Friday)
Issued at 345 PM CDT Fri Mar 24 2017
The 12z GFS and ECMWF models show the next wave to have an impact
on Central Plains weather moving out of the Rockies and into the
central High Plains on Sunday. There will be some moisture return
ahead of this system so the going chance for rainshowers looks
good. The models continue to be in good agreement with the long
advertised upper low pressure system that is progged to dig into
the Intermountain West on Monday into Monday night and then move
out across northwest Texas and Oklahoma through the middle of next
week. While there is some disagreement in where the most
significant rainfall will be with this system, it appears that a
good part of the central High Plains is in for some decent
rainfall that could put a little dent in the drought conditions
and get the spring greenup going in earnest. Temperatures through
the week will be fairly seasonal.
Beyond midweek, the models are in remarkable agreement with another
upper low system digging into the central/southern High Plains by
next weekend. The currently progged track of this system could
also bring some beneficial precipitation to western Kansas but a
little more uncertainty exists given how far out in the extended
period this is.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 638 PM CDT Fri Mar 24 2017
As the upper low pulls away through the night, we will continue to
see cold advection and remnant low clouds behind the cyclone,
leading to IFR ceiling around 700 to 1000 feet. The ceiling may
periodically go into MVFR, but the best indication is that ceiling
will predominantly be in the upper IFR cat. In the 09-12z time
frame, ceiling will scatter and we will see VFR conditions
resuming areawide. Winds will remain from the north to northwest
through the period with a gradual decrease in intensity through
the TAF period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 65 40 67 / 40 0 0 30
GCK 33 65 40 63 / 10 0 0 40
EHA 32 67 39 63 / 0 0 0 20
LBL 35 67 40 69 / 10 0 0 30
HYS 38 60 38 62 / 20 10 0 30
P28 43 64 41 73 / 50 10 0 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gerard
LONG TERM...Gerard
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
950 PM CDT Fri Mar 24 2017
.UPDATE...
Dry air aloft continues to filter into most of South Central Texas on
the southwest side of a strong upper level low over Central Oklahoma.
Although surface dew points in the 60s are gradually retreating west
towards the I-35 corridor, this will be short lived as the synoptic
cold front currently located just north of Sonora to DFW moves into
the region. The front moving through the I-35 corridor around 1 am
and clears the Coastal Plains by 5 am should quickly halt surface
moisture recovery. Although isentropic descent will quickly fill in
behind the front, there may be a very brief window for showers and
possibly a thunderstorm in the Coastal Plains as SW-NE isentropic
descent moves in just ahead of the front. However, hi-res models are
trending towards a faster progression of the front and holding off
on triggering showers and thunderstorms until after it clears our
CWA. Considering surface convergence will be very weak, we only have
20 POPs over parts of Fayette and Lavaca Counties tonight. Patchy
fog may occur in the Coastal Plains after Midnight before quickly
lifting behind the front. Aside from that, only minor grid edits
were made based on model and observational trends.
&&
.PREV DISCUSSION... /ISSUED 743 PM CDT Fri Mar 24 2017/
UPDATE...Corrected to change sunset to sunrise below...
Winds continue to remain above 15 mph out in parts of Val Verde and
Edwards Counties with relative humidity values remaining around 10-15
percent. Therefore, we have extended the Red Flag Warning for those
three counties for one hour to 8 PM for Val Verde, Edwards, and
Kinney Counties in coordination with FWD and SJT. Winds should fall
below 15 mph and relative humidity values should recover back above
20 percent within the next hour or so.
The showers and thunderstorms that developed along a confluence
boundary just west of the Highway 77 corridor have all moved out of
the county warning area except for one cell in Lavaca County that
moved just to the south-southeast of Hallettsville. We continue to
monitor that cell as storm-relative helicity values remain in the
200-300 m^2/s^2 range and we did have a cell briefly pulse to
possibly produce severe hail in NE Fayette County. However, mid-level
lapse rates remain very modest at 6-6.5 deg C/km, so the potential
for that storm to become severe remains low at this time. Once that
cell exits the CWA within the hour, all storm activity should end
until possibly late in the overnight hours around sunrise in the
Coastal Plains once the synoptic cold front moves through. We will
do one more grid update in the next few hours to address this, but
20 POPs seem reasonable for now.
PREV DISCUSSION... /ISSUED 643 PM CDT Fri Mar 24 2017/
AVIATION.../00Z TAF CYCLE/
VFR conditions prevail across all terminals late this afternoon and
are expected to continue through the TAF period. Isolated TSRA is
ongoing across the Texas Coastal Plains towards Houston. This
activity will shift northeast through the early evening hours into
East Texas. Surface winds remain gusty from the south and west for
KDRT/KAUS at 15-20 knots. These winds will subside next few hours to
sustained winds near or less than 10 knots from the west. Winds will
then shift more northerly through early to mid morning Saturday as a
dry front moves through the region. Low ceilings are likely to return
by Sunday morning however as moisture returns to the region.
PREV DISCUSSION... /ISSUED 320 PM CDT Fri Mar 24 2017/
SHORT TERM (Tonight through Saturday Night)...
Pacific front/dry line was near the I-35 corridor mid afternoon.
Dry slotting has occurred across the southern I-35 corridor. Farther
northeast aircraft soundings near AUS indicate the mid level cap
weakening. There is still a window through late afternoon and early
evening where a strong to marginally severe storm or two could form
across the EWX CWA near and east of U.S. 77. However the better
threat this afternoon and into tonight will be northeast of the area.
A secondary push/front will move into the area after midnight.
The latest few HRRR runs were showing the possibility of convection
developing along this boundary overnight across the far eastern CWA.
In addition, with the initial front/dry line slowing down there will
be a window for fog late tonight across the far southeast counties
before the secondary push of drier air arrives. Sunny and dry on
Saturday.
LONG TERM (Sunday through Friday)...
A progressive pattern will occur through the upcoming week. On
Sunday a weak shortwave will pass through the Southern Plains. A warm
front looks to come back into the CWA Sunday morning and then a dryline
gets dragged east into the western CWA Sunday afternoon. This will
lead to a warm day, especially across the southwest CWA where highs
could climb into the mid 90s. Upper 80s to low 90s are expected
elsewhere. A weak cold front looks to enter the area Monday and
results in highs a degree or two cooler.
Models are then consistent with an upper level low digging into the
Four Corners Tuesday and a rapid moisture return taking place across
South Central Texas ahead of it on Tuesday. Isolated to scattered
showers and storms are possible during the day on Tuesday, favoring
central and western areas of the CWA. This upper level low is
forecast to dig slightly farther south into Texas than the current
system, coming out into West Central Texas Wednesday morning.
South Central Texas becomes placed in a favorable location Tuesday
night into Wednesday morning, with a diffluent flow aloft between
the upper level low to the northwest and sub-tropical jet streak
just to the south. As large scale ascent spreads into the area late
Tuesday night through Wednesday morning both the GFS and ECMWF are
indicating showers and storms increasing in coverage, especially
across the Hill Country and I-35 corridor Tuesday night and along and
east of I-35 Wednesday morning. There are hints that a heavier band
of rainfall could occur near and east of I-35. Ingredients may come
into play for locally heavy rainfall but too soon to determine exact
amounts and locations. There could also be a threat for severe storms
as an organized convective complex may try and develop.
The area looks to eventually get dry slotted Wednesday afternoon from
west to east. GFS is a little more robust with mid level moisture
wrapping around the upper level low Wednesday night and Thursday and
is generating some QPF. Have retained some low pops across the
northeast half of the CWA during this time.
Dry conditions on Friday and then both the GFS and ECMWF indicate
another upper level system possibly impacting the CWA just beyond
Day 7.
FIRE WEATHER...
Winds have been a little slow to respond but in the past hour have
begun to see winds increasing across the western Hill Country and
Edwards Plateau. There will be a window now though sunset where
occasional wind gusts to around 25 mph could occur across Edwards and
Val Verde Counties and possible as far south as Kinney County. RH
values are currently bottoming out around 8-15 percent and should the
winds become gusty this will result in a critical fire danger. Will
allow the Red Flag Warning to remain in place until 7 PM.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 55 81 58 87 63 / - 0 0 10 20
Austin Bergstrom Intl Airport 52 81 55 87 62 / - 0 0 10 20
New Braunfels Muni Airport 52 82 56 87 62 / - 0 0 10 10
Burnet Muni Airport 50 78 56 85 58 / 0 0 0 10 20
Del Rio Intl Airport 53 84 57 91 57 / 0 0 0 0 0
Georgetown Muni Airport 52 79 55 86 61 / - 0 0 10 20
Hondo Muni Airport 49 86 56 90 59 / 0 0 0 - 10
San Marcos Muni Airport 53 82 56 87 63 / - 0 0 10 10
La Grange - Fayette Regional 58 80 57 86 66 / 20 - 0 10 20
San Antonio Intl Airport 53 84 58 88 62 / 0 0 0 10 10
Stinson Muni Airport 53 83 58 88 62 / 0 0 0 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Allen
Synoptic/Grids...LH
Public Service/Data Collection...Williams
Area Forecast Discussion
National Weather Service Green Bay WI
1053 PM CDT Fri Mar 24 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 238 PM CDT Fri Mar 24 2017
The latest RAP analysis and satellite/radar imagery show an occluded
low pressure system located over the panhandle of Oklahoma early
this afternoon and a shortwave trough moving east over northern
Ontario. An elongated area of mid-level convergence is occurring
between these two features, which is contributing to the band of
rain currently moving across central and northeast WI. Behind the
shortwave, high pressure is building southeast over northern
Manitoba, which will drive the band of rain southward towards
central WI through the rest of the afternoon. Forecast concerns
mainly revolve around precip trends over the next 24 hours.
Tonight...Low pressure will slowly move east across the central
Plains while a strong high pressure system builds southward into
northern WI. With a stronger push of dry air from the north, the
band of precipitation will get shoved southward through the night,
resulting in the most widespread rain occurring over central and
east-central WI. North-central WI could see some rain persist on the
northern edge of the band early this evening before it pulls out.
But by exiting the north early in the night, this will negate
another chance of freezing rain. Low temps ranging from the upper
20s in the north to the middle 30s in the south.
Saturday...The low pressure will continue to migrate east into the
central Mississippi Valley. But as the high retreats, rain will
gradually return northwest from east-central WI in the morning, back
into central and northeast WI in the afternoon. North-central WI
will likely escape the rain, being located in closer proximity to
the dry Canadian high to the north. With the rain and gusty
northeast winds, eastern WI will mostly likely be a few degrees
colder than locations over central and north-central WI.
.LONG TERM...Saturday Night Through Friday
Issued at 238 PM CDT Fri Mar 24 2017
Long term period starts out active with on-going chances for rain
and freezing pcpn as a surface and upper level low continue the
slow moving journey from Missouri to southern Lake Michigan
through the weekend. A quiet period looks more likely for the
middle of next week.
PoPs expand back into northern Wisconsin Saturday night as the
low moves closer to Wisconsin. Guidance would suggest boundary
layer temperatures falling below freezing in roughly the
northern half of the forecast area. An elevated warm layer is
evident during this time as well. This introduces freezing rain,
and perhaps some sleet, into the forecast through Sunday morning.
If precip timing and cooling temps lined up right, this could
result in ice accumulations around a tenth of an inch north of a
line from about Merrill to Antigo to Wausaukee. At this time
confidence is not high as this once again depends on the exact
timing of when the pcpn moves north and if temperatures get cold
enough. Will let later shift re-evaluate the potential. Any
freezing pcpn would switch back to rain by mid-morning Sunday.
The low moves east of Wisconsin Sunday night into Monday morning.
Another rough of freezing rain/sleet is possible in the far north
Sunday night, but with the bulk of the moisture and energy now to
the east wouldn`t expect more than a hundredth or two of icing to
occur in isolated areas.
Models in good agreement that the system moving out of the
southwest Monday into Tuesday will stay well south of Wisconsin.
By this time there may still be a hint of wrap around precip from
the weekend system through Monday morning. GFS, ECMWF, and
Canadian models all suggest a surface high and mid and upper
level ridge building in Monday afternoon, and will keep the area
dry Tuesday and Wednesday. High temperatures also get a boost
during this time.
For Thursday and Friday, another system moves out of the southwest
similar to the one currently affecting the Upper Midwest. However,
models vary significantly on placement of the low and its main
features. If southern solution pans out wouldn`t expect much pcpn
in the forecast area during this time. Northern solution could
result in a similar event with daytime rain and overnight mixed
precip. Kept with the blended model solution for now until these
details are able to get sorted out a bit better.
Rain and clouds will keep high temperatures within a few degrees
of seasonal normals through the weekend, in the upper 30s and
lower 40s. Highs should warm into the upper 40s and lower 50s next
week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1053 PM CDT Fri Mar 24 2017
Little change expected overnight with plenty of IFR/MVFR
cigs holding across northeast WI. The band of showers over
central/east-central WI is forecast to shift south later tonight,
but return Saturday afternoon to central/east-central WI and
Saturday evening across northern WI. This precipitation activity
tied to a frontal boundary that is expected to lift north ahead of
a system moving across the central Plains. There may be a brief
improvement to high MVFR or low VFR cigs Saturday afternoon.
However, as the rain approaches late Saturday/Saturday night, look
for cigs/vsbys to return to at least IFR conditions.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KLB
AVIATION.......AK
Area Forecast Discussion
National Weather Service Louisville KY
947 PM EDT Fri Mar 24 2017
.Forecast Update...
Issued at 945 PM EDT Fri Mar 24 2017
Current forecast remains on track for the overnight period. Plenty
of mid-high level clouds will continue to stream overhead with
showers arriving in our western counties Saturday morning.
&&
.Short Term (Now through Saturday Night)...
Issued at 249 PM EDT Fri Mar 24 2017
A southerly breeze and partly to mostly cloudy skies will keep
temperatures elevated tonight, with most lows in or around the upper
50s/60.
Low pressure will move NNE across Missouri Saturday and Saturday
night with its warm front well to our north. Even with increasing
cloudiness and showers/storms moving in in the afternoon, models
will underestimate high temperatures in the deep, strong WAA
tomorrow, so will go above guidance for MaxT. The showers and storms
will be most likely in the afternoon, especially west of I-65. (Some
models, like the RAP and the 3km NAM, actually hold precip off until
evening.)
It will be a breezy day in the warm sector with afternoon gusts of
30 to 35 mph possible, especially in the Bowling Green region.
Showers and scattered thunderstorms are virtually a certainty
Saturday night as the low to our west pushes a weak surface trof
through the Ohio Valley with deep moisture to work with. General
rainfall totals should be around half an inch.
.Long Term (Sunday through Friday)...
Issued at 258 PM EDT Fri Mar 24 2017
The Missouri surface low will slowly fill as it heads into the Great
Lakes by Monday morning with showers and thunderstorms continuing
out ahead of it. A 5h speed max coming in from the west Sunday
afternoon could enhance thunderstorm development in eastern sections
of central Kentucky.
After a brief break Sunday night, the next low will move from the
Ozarks to southern Great Lakes Monday-Monday night and bring more
showers and thunderstorms along with it. The better instability and
upper dynamics will be over the lower Mississippi Valley, but mid-
level lapse rates will steepen here in the afternoon coincident with
the low approaching from the west, so a few stronger storms Monday
afternoon aren`t entirely out of the question.
Tuesday the upper trof from the previous day will be off to our east
with some weak ridging moving in. Models do show lingering sfc-
850hPa moisture, with some light rain showers possible primarily in
the morning before the surface trof completely clears the area.
After a mid-week break, the next system will come out of the Plains
late in the week and bring more showers Thursday-Friday.
With the active storm track, no intrusions of Canadian air are in
our near future. The coolest morning will probably be on Thursday
with lows upper 40s to lower 50s.
&&
.Aviation...(00z TAF Update)
Issued at 702 PM EDT Fri Mar 24 2017
Main concern is LLWS threat overnight and then shower and
thunderstorm chances Saturday afternoon across central Kentucky.
Breezy south winds continue across the region and will relax
somewhat but stay around 10 kts through the evening. A 45 kt jet out
of the southwest will set up overnight, at about 2000 ft, and will
bring marginal LLWS conditions to central Kentucky.
Inversion should break between 13-14z giving way to gusty south
winds. Expect 20 to 25 kt gusts during the late morning and
afternoon. Shower chances will increase in the afternoon, and will
introduce VCSH 21z and after. A few thunderstorms will be possible
at BWG, possibly as far north as SDF and LEX. Looking ahead, some
MVFR ceilings and better coverage of showers and some thunderstorms
are likely after 00z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update............MJ
Short Term........13
Long Term.........13
Aviation..........ZT
Area Forecast Discussion
National Weather Service Medford OR
807 PM PDT Fri Mar 24 2017
.DISCUSSION...A cold front moved through today and brought heavy
rain and some mountain snow over the past 24 hours to portions of the
forecast area. From Illinois Valley north to Roseburg and points
west, the general rainfall amounts since yesterday afternoon were
1-2 inches. The Cascades received about a half inch to an inch,
while areas east of the Cascades received a quarter inch of
precipitation or less. About a foot of snowfall was observed at
the Annie Springs SNOTEL observation site near Crater Lake at
6000 feet.
Showers are currently diminishing behind the front, and there is
another shortwave trough moving towards the coast, but satellite
imagery suggests is has little punch, and HRRR output suggests
spotty rainfall with it and most occurring near the coast or in
the Cascades.
Midlevel moisture decreases tomorrow and, with an increasingly
stable air mass, most areas will be dry. Low level moisture does
remain high though, and simulated satellite imagery forecasts
suggest partly to mostly cloudy skies in most areas.
A hefty weather system arrives Sunday, and the previous forecast
discussion below provides details about expected impacts.
&&
.AVIATION...25/00Z TAF CYCLE...a mixture of VFR and MVFR Ceilings
will continue through this evening, especially during periods of
showers. This will lead to terrain and mountain obscuration
overnight. Conditions will be persistent overnight into Saturday
morning with a slight decrease in the coverage of showers and an
increase in west side valley MVFR. It`s likely that most locations
will become VFR by Saturday afternoon at the latest. FJB/SK
.MARINE...Updated 200 PM PDT Friday 24 March 2017...Seas will
remain steep into Saturday afternoon due to a combination of
moderate westerly swell and fresh short period southwest swell. Seas
will be highest in the outer waters and near Cape Blanco with seas
just a foot or two below advisory criteria in the near shore waters.
Improvement will be brief with the next front likely to produce
advisory winds late Saturday night then arrive early Sunday morning
with another round of very steep seas and possible gales. We have
issued a Gale Watch with winds rising as early as mid morning
Sunday. /FB
&&
.PREV DISCUSSION... /Issued 258 PM PDT Fri Mar 24 2017/
DISCUSSION...
Short Term...Tonight through Monday Night...The front has all
but passed through the area, and while the bulk of the
precipitation has moved to the east, numerous showers will
continue through this evening and into tonight. Wind and winter
weather advisories have come to an end, but snow showers may drop
some additional light accumulations, and some breezes are still
possible, especially in the aforementioned showers. Most
precipitation should end overnight, but some residual showers
could continue into Saturday morning.
High pressure and upper level ridging will attempt to nudge in on
Saturday, and should provide some clearing and what may turn out
to be a pleasant afternoon. The break in the wet pattern will be
short lived, however, as the next front will begin to make its way
into the region late Saturday night or early Sunday morning.
Sunday will turn out to be another wet and windy day with snow
levels between 4000 and 5000 feet. Models have backed off a bit
with the amount of moisture that the system has available, but it
will take a bit for the front to pass, and the duration of the
precipitation will make up for the lower rates. Other than the
speed and lower moisture content, the system will be very similar
to the one that juts passed, and wind and/or winter weather
advisories may be needed for Sunday afternoon and evening.
Uncertainty still remains too high in terms of timing and
magnitude, so will leave the final decision on headlines for the
upcoming shifts.
Post-frontal showers will then continue into Monday, but clearing
is expected by Monday afternoon and evening as ridging builds
into the West Coast. -BPN
LONG TERM...Tuesday through Friday.
In general terms, the seasonably wet pattern looks to continue
through the long term. Our area will be between a ridge offshore of
central and southern California and a trough in the Gulf of Alaska.
A series of disturbances in a westerly flow will move into the
Pacific Northwest. As such, the main uncertainty is the timing and
southward extent of these systems.
The probability of precipitation throughout the long term was
adjusted to reflect a blend of the latest 12Z ECMWF and GFS Ensemble
data, and will be highest in the western and northern portions of
our area. Temperatures and snow levels were nudged higher, closer to
normal.
Specifically model agreement is not bad on Tuesday into Tuesday
night with a warm front likely focusing rain on Washington. The
GFS keeps rain north of our area while the ECMWF is a bit stronger
and farther south...spreading rain into southwest Oregon and
northern Klamath County.
Model agreement diminishes Wednesday but the probability of
precipitation increases with the trailing cold front likely to
weaken as it moves through the Pacific Northwest Wednesday through
Wednesday night. There is considerable uncertainty on whether we
will or will not receive the brunt of what is likely to be a front
of moderate/seasonably typical strength.
It will be cooler and there is a chance of post-frontal showers in a
northwest flow as an upper trough moves inland on Thursday.
Ridging is likely to follow Thursday night into Friday with a
pattern similar to that of Tuesday...the next front will likely
track inland north of our area with the highest probability of
light rain at the coast north of Cape Blanco. -DW
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...Gale Watch from Sunday morning through Sunday afternoon for
PZZ350-356-370-376.
Small Craft Advisory for hazardous seas until 11 PM PDT Saturday
for PZZ350-356-370-376.
$$
NSK/DW/FJB
Area Forecast Discussion
National Weather Service Spokane WA
750 PM PDT Fri Mar 24 2017
.SYNOPSIS...
Scattered mountain showers will continue overnight. Showery and
breezy is expected weather for Saturday. Sunday looks dry.
Unsettled weather returns Sunday night into Monday and continues
through next week, with several more rounds of rain and mountain
snow expected.
&&
.DISCUSSION...
Made a few updates to the forecast. Front has moved quickly
through eastern Washington this evening and is making its way
through north Idaho before midnight. Skies cleared behind the
front, although mid level clouds and instabiltiy will increase as
the upper trough moves over the region along with a weak embedded
impulse. The HRRR has done a good job on the exit to the front,
but it does indicates some light showers across the northern
mountains overnight. Breezy post frontal westerly winds span the
Columbia Basin, into the Palouse and Spokane area. /rfox.
&&
.AVIATION...
00Z TAFs: Radar shows back edge of the rain reaching the KGEG-KCOE
corridor and KPUW area by 02z with clearing lagging behind. VFR
conditions expected in KEAT, while the IFR cigs in KMWH should
improve early this evening. KLWS hasn`t seem much pcpn and despite
the lower cloud deck, conditions should stay VFR. West to
southwest flow will prevail through the night and keep the
boundary layer mixed. So confidence on fog forming is low,
although some low sct stratus is possible through early morning.
TAF sites should remain mostly dry with an increase of a
stratacumulus deck in the eastern TAF sites. Light showers are
possible after 21z near KCOE and in the Panhandle mountains.
/rfox
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 50 32 49 38 51 / 40 30 10 40 70 70
Coeur d`Alene 36 48 31 48 36 48 / 70 50 10 30 80 70
Pullman 37 49 34 51 39 49 / 10 30 10 40 70 80
Lewiston 39 55 37 55 41 55 / 10 40 10 30 60 70
Colville 35 50 29 47 35 49 / 20 30 10 30 60 60
Sandpoint 33 46 30 46 33 46 / 70 70 20 10 80 70
Kellogg 34 44 31 47 34 44 / 80 80 20 20 90 70
Moses Lake 37 58 32 53 39 58 / 0 10 10 50 60 20
Wenatchee 35 53 32 47 36 53 / 0 0 0 60 70 20
Omak 35 53 29 48 36 53 / 10 10 0 60 70 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Norman OK
1034 PM CDT Fri Mar 24 2017
.DISCUSSION...
&&
.AVIATION...
Gusty northwest winds will follow a front now moving through
central Oklahoma. MVFR ceilings are expected over the northern
two-thirds of Oklahoma tonight while an upper storm system moves
west to east. Ceilings will lift and clear Saturday morning west
to east and winds will decrease through the afternoon.
&&
.PREV DISCUSSION... /issued 712 PM CDT Fri Mar 24 2017/
DISCUSSION...
AVIATION...
Light showers will move east across central Oklahoma this evening
underneath an upper low pressure system. Gusty southwest winds
will become north in central Oklahoma late this evening when a
front passes northwest-to-southeast. Gusty winds will slowly
diminish Saturday morning. A period of MVFR ceilings will sweep
across the northern two-thirds of Oklahoma overnight with the
upper storm.
PREV DISCUSSION... /issued 244 PM CDT Fri Mar 24 2017/
DISCUSSION...
Closed vertically stacked low is evident in radar and satellite
observations over the eastern Texas Panhandle. The presentation in
water vapor channel is particularly impressive and a well-defined
mid-level intrusion of dry air is seen moving across central
Oklahoma at this time. As deep mixing into this dry area
continues, surface dew points continue to fall and many locations
are already experiencing relative humidity values in the teens
already early this afternoon. The combination of dry air (dries
across central Oklahoma beneath the dry slot) and strong
southwesterly winds leads to continuation of fire weather
concerns. Near critical to critical fire weather conditions will
persist into the evening and so the Red Flag Warning continues.
Further west, with the main low circulation, visible satellite
and surface observations show fairly high based cumulus and
strato- cumulus. Radar shows bands of showers as well. Instability
to the east is meager owing to deep mixing/drying and so as the
low progresses east, much of western Oklahoma should not
experience more than passing light showers. Although, some
momentum transfer from showers could lead to brief bursts of
stronger winds and evaporative cooling process will probably cause
a sudden drop in temperatures.
Further east, where deep mixing is occurring, veering of surface
winds have been observed. Meanwhile to the east, winds remained
slightly backed with low level moisture still flowing north-
northwest into the far east and especially northeast portion of
the area. There may be an opportunity for deeper convection across
this area, particularly as fairly dramatic mid-level cooling with
the deep low approaches. Forecast soundings from RAP suggest
around 700 j/kg MLCAPE and veering low level winds and deep layer
shear supportive of storm organization/persistence. Thermal
profiles and distribution of CAPE, as well as character of the
CAPE within the hail growth zone would be supportive of marginally
severe hail, although some storms may be capable of fairly
sizeable quantities of smaller hail. North-central Oklahoma is
where the greatest threat of strong/severe thunderstorms exists.
Further south, significant mid-level moistening in close proximity
to the deep low could result in a period of high based showers,
and at least a low probability of measurable amounts as far south
as around I-40.
Fairly short wavelength between departing upper low and the next
shortwave/closed low raises some question on magnitude of moisture
return. Nevertheless, moisture seems sufficient to support at
least modest instability and thunderstorm formation east of a
dryline Sunday afternoon, with upscale growth likely into the
evening as deeper moisture advects in. The severe threat will
exist including the possibility of supercells. The details with
regard to low level moisture, low level shear, etc., will need to
be better refined before we have confidence on convective hazards.
Another concern Sunday is dry windy conditions behind the dryline
Sunday. Fuels visually are becoming green especially along roads
in ditches, but open fields still have plenty of dormant fuels
and ERC-G values are on the very high end of normal. Given this,
at least elevated to near critical conditions seem likely across a
good portion of the area. Mainly southwest Oklahoma and western
north Texas.
The active pattern continues into next week. Confidence is growing
on a much needed rain event from late Tuesday into early Thursday.
Timing of the highest precipitation probabilities and amounts will
need to be refined as ensemble spread lessens and determinist
guidance comes into better agreement.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 49 67 47 80 / 30 0 0 30
Hobart OK 45 70 47 80 / 20 0 0 10
Wichita Falls TX 49 72 50 85 / 10 0 0 10
Gage OK 41 69 44 76 / 20 0 0 20
Ponca City OK 48 62 43 75 / 40 10 0 40
Durant OK 52 71 49 81 / 10 0 0 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
04/09/09
Area Forecast Discussion
National Weather Service Topeka KS
634 PM CDT Fri Mar 24 2017
...AVIATION UPDATE...
.SHORT TERM...(This evening through Saturday)
Issued at 257 PM CDT Fri Mar 24 2017
Increasing isentropic lift within the warm sector this afternoon has
produced scattered showers and thunderstorms in the early
afternoon. Current position of the upper low was rotating through
the OK panhandle with the sfc low directly beneath. Frontal boundary
positioned from southwest to northeast over north central KS through
IA coincides with an additional dryline/front extending south of the
sfc low across central KS. Cloud cover and morning thunderstorms
have hindered sfc heating and instability across the CWA, leading to
further uncertainty with how severe storms will be later in the
afternoon and evening. Current analysis shows around 500 J/KG of sfc
based cape across central KS, in vicinity of the triple point with 0-
6 km bulk shear in excess of 40 kts. As the main system shifts east
southeast, bulk shear on the RAP increases towards 60 kts,
supportive of updrafts, however dependent on how much instability is
realized for supercells.
Current thinking is that scattered convection initializes along and
ahead of the southeast moving front after 3 PM (centered near the I
70 corridor), capable of producing large hail and damaging winds
near and south of the boundary. As convection lifts north of the
front, they should weaken. Latest runs of the HRRR and RAP depict a
few supercells developing east of Wichita, lifting north and east
into east central KS through 00Z. These storms may also produce
large hail and damaging wind gusts, especially if higher instability
is realized. As the upper low shifts over OK during the evening and
overnight periods, showers and scattered thunderstorms gradually
weaken and quickly lift off towards the north and east. Expect to
see off on and showers with embedded thunder overnight as weak mid
level frontogenesis wraps around the backside of the system.
On Saturday, model guidance is trending towards a slower
progression with the upper low exiting the CWA. Increased pops
in the morning through early afternoon hours with the scattered
showers gradually clearing east by the evening. Northerly winds
overnight and Saturday gust up to 25 mph under overcast skies,
resulting in a much cooler afternoon with highs in the 60s.
.LONG TERM...(Saturday night through Friday)
Issued at 257 PM CDT Fri Mar 24 2017
The unsettled weather pattern will continue at least through the
next 10 days with 4 storm systems very likely to impact the
central plains during that time frame. The first system over the
area today will exit with precipitation ending by late Saturday.
By late Sunday afternoon, a quick-hitting short wave trough will
cross Kansas, taking on a negative tilt and pulling a quick return
of modified gulf moisture into eastern Oklahoma...and to a lesser
extent eastern Kansas. Locally, instability will likely be limited
by unimpressive lapse rates and boundary layer moisture. However,
widespread vertical motion on the north quadrants of the system
suggests a high likelihood for precipitation especially along and
south of I-70. Temperatures will be warm enough to support an all
rain forecast. This system will exit quickly with fairly pleasant
conditions for Monday and Tuesday.
A stronger, deeper upper trough is forecast with good model
agreement to enter the plains Tuesday night and slowly progress
east before taking on a negative tilt and accelerating out of the
area late Thursday. The current storm track would take the heart
of this trough south of the forecast area, so while it should be
quite effective in northward transport of gulf moisture, the best
dynamics, shear, and instability will likely remain well south of
the forecast area. However, the strong mid and upper level forcing
in the northern quadrants of the trough will once again give a
good chance for widespread rain across the area. This is one of
those storms that would have been a great snow storm if it had
happened 2 months ago and 20 degrees colder...but in this scenario
looks to likely fall as all rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday)
Issued at 633 PM CDT Fri Mar 24 2017
Models continue to show conditions deteriorating through the
evening as wrap around moisture brings MVFR and IFR CIGS to the
terminals. Think that once the frontal boundary moves through the
area, chances for thunderstorms will wane with the lose of
surface instability. There does not appear to be much improvement
for Saturday with low levels remaining saturated as the low
pressure system slowly moves east.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Prieto
LONG TERM...Barjenbruch
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Las Vegas NV
847 PM PDT Fri Mar 24 2017
.SYNOPSIS...
High pressure will push eastward tonight as next system approaches
the west coast. Gusty winds and chances for rain and higher elevation
snow will increase tonight and Saturday. Widespread showers are
expected to develop across the Sierra, the southern Great Basin,
and northern Mohave county. Elsewhere, isolated, light showers
will be possible. A couple more rounds of weather are expected
next week with similar conditions as additional disturbances pass
across the region.
&&
.UPDATE...Radar shows a 50-100 mile wide band of light rain running
from Santa Barbara County northeast across the San Joaquin Valley
and into the southern Sierra Nevada. Have had some light rain in
northern Inyo County around Bishop while an automated station near
South Lake above 10000 feet indicates around 2 inches of new snow.
As upper trough moves in off the Pacific tonight, models in
agreement line of showers will fill in across northwest San
Bernardino, eastern Inyo, Esmeralda and Nye Counties around
midnight. The line will move east toward Pahrump, Las Vegas and
Lincoln County during the early morning hours. HRRR shows this band
moving through Las Vegas between 5 and 7 am Saturday. The widespread
precipitation will stay confined to Lincoln County Saturday morning.
Isolated to scattered showers will redevelop Saturday afternoon as
cold pool aloft associated with trough passes over. Precipitation
looks to end quickly over Mohave County Saturday evening as upper
trough races east. No update this evening as package looks in good
shape.
&&
.PREV DISCUSSION...231 PM PDT Fri Mar 24 2017
.SHORT TERM...through Saturday night
Ridge will continue its progression eastward as a Pacific trough
pushes onshore of the west coast Saturday morning. Ahead of the
trough precip chances will spread southeastward towards the the
I-15 corridor by tomorrow morning and continue towards I-40
throughout the day on Saturday as trough passes across the region.
Best chances remain along the Sierra, the southern Great Basin,
and northern Mohave county where numerous showers are expected to
develop. Snow levels should briefly lower to around 6500` late
tonight into tomorrow morning over the Great Basin where between
a trace to 3 inches of snow is possible across the higher
elevations. An isolated thunderstorm cannot be ruled out across
northern Mohave and eastern Lincoln counties Saturday afternoon
but confidence is low in this occurrence so have left out of
forecast for now. Elsewhere, primarily dry conditions expected with
a brief light rain shower possible. Gusty winds will accompany
this system overnight Friday into Saturday morning shifting from
southwest to northwest on Saturday in the wake of the trough.
Sustained winds around 20 mph gusting 30 mph are likely overnight.
Rain chances diminish quickly Saturday night on the backside of
trough as weak ridge builds over the area through Sunday morning.
.LONG TERM...Sunday through Thursday.
Active pattern continues as two storms are likely to affect the
region during the period. Models have come into better agreement
with the first storm Monday and Tuesday, so confidence is increasing
then, but agreement is poor for the second storm Thursday, so
confidence is below average then. Sunday should be dry areawide
until the first storm rolls in from the west, with precip chances
increasing in the Sierra in the afternoon and possibly spreading
into the southern Great Basin overnight. The models have come into
better agreement this morning on what is essentially a compromise
solution between the weaker and faster ECMWF of the past few days
and the slower and stronger GFS of the past few days. This
compromise shows the shortwave trough passing through Monday, with
precip chances limited to areas near and north of Las Vegas, before
deepening and digging over the Four Corners region Monday night.
This will keep precip chances going mainly in Lincoln and Mohave
counties Monday night, but the biggest impact will likely be gusty
north winds beginning over the northwest zones Monday afternoon and
spreading areawide by Tuesday. Wind Advisories may be needed. After
a dry period Tuesday and Wednesday, the next storm could start to
bring precip chances back to the area Thursday. The models agree on
the existence of this storm, but do not agree on its track or
timing, so confidence in where to put the best precip chances is
very low. Temperatures should stay close to late March averages
through the period, with areas of well below normal temps possible
wherever precip and/or thick clouds persist through the day on
Monday or Thursday.
&&
.AVIATION...For McCarran...Winds will continue to veer around to
the southwest by this evening becoming gusty overnight around
20 to 25 knots. Westerly winds Saturday morning are expected to
shift to the northwest Saturday afternoon as trough passes across
the area. This system will also result in increasing mid and high
cloud coverage and very isolated shower activity across the Vegas
area on Saturday.
For the rest of southern Nevada, northwest Arizona and southeast
California...Winds will continue to veer around to the southwest
by this evening becoming gusty overnight around 20 to 25 knots in
most areas. Higher gusts will be possible in the vicinity of the
Sierra and Spring mountains. Westerly winds Saturday morning are
expected to shift to the northwest throughout the day as trough
passes across the area. This system will also result in increasing
cloud cover and rain chances across the Sierra this evening,
spreading across central and southern Nevada and northwest Arizona
on Saturday. A very isolated thunderstorm will be possible across
northwest Arizona Saturday afternoon.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
Update...Pierce
Long Term...Morgan
Short Term/Aviation...Guillet
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