Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/01/18
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
245 PM AKDT Sat Mar 31 2018
A ridge will build over the Bering sea and stretch northward
across the bering strait through Monday. A shortwave will move
east across the western north slope tonight and continue to track
to the east and will be over the eastern North Slope on Sunday.
Another shortwave will track across the Interior Saturday evening
bringing a shot of snow for the Middle Tanana Valley. On Tuesday
a cold 518 dam low will push southward into the western Interior
and deepen to 510 dam by Wednesday afternoon over the Yukon Delta
then move over Bristol Bay on Thursday.
Surface...A frontal boundary will sweep across the north slope
bringing snow and gusty winds this afternoon and will push over
the Beaufort Sea coast and into the Interior this evening. A 1042
mb high will build over the Bering sea and build northward over
the weekend and into next week.
West Coast and Western Interior: Fog and low clouds will persist
along the west coast into early Sunday (the HRRR actually has a
solid area of low visibility fog stretching from the Bering Strait
Coast southward to the Yukon Delta through early Sunday morning).
Dense fog headlines added for zones 213 and 211 for dense fog
around Nome and the Bering Strait. High pressure will build north
across west coast on Sunday, keeping the west coast free of
precipitation Sunday through Tuesday. Low level winds will
strengthen and become northeasterly on Tuesday.
North Slope and Brooks Range:
Winter weather advisories still in effect for zones 202 and 203. A
blizzard warning is in effect for zone 204. Snowfall amounts
around the 2 to 4 inch range with locally higher amounts over the
Eastern Brooks range through Sunday morning. A tight pressure
gradient will produce westerly winds gusting to 50 mph near Barter
Island area Sunday into Monday. High pressure will build along the
north side of the Brooks Range this evening. This will cause
strong northerly gap winds to develop in Brooks Range Passes. The
gap winds in the Brooks Range combined with falling snow will
result in blowing snow reducing the visibility to one half mile or
less at times into Sunday.
Central and Eastern Interior: Snow will begin to develop across
the Middle Tanana Valley late this afternoon due to a frontal
boundary and an increase in moisture. Expecting 1 to 3 inches
with the heaviest amounts south of Fairbanks and near the Alaska
range due to upslope enhancement. The snow will gradually taper
off Sunday morning. In addition to the snow, wind gusts as high as
25 mph will cause blowing snow reducing the visibility at times
mainly over higher terrain. Blowing and drifting snow possible
over the summits of the Steese, Dalton and Elliott Highways.
Winter weather advisories are in effect for snow and blowing snow
for zones 220 218 and 219. High pressure will build over the
Interior on Monday drying things out. Little to no precipitation
through mid week for the Interior.
Coastal Hazard Potential Days 3 and 4...None.
Blizzard Warning for AKZ204.
Winter Weather Advisory for AKZ202-AKZ203-AKZ206-AKZ218-AKZ219-
Gale Warning for PKZ240-PKZ245.
Brisk Wind Advisory for PKZ230-PKZ235-PKZ240-PKZ245.
JK MAR 18
Area Forecast Discussion
National Weather Service Albany NY
1033 PM EDT Sat Mar 31 2018
A strong cold front will cross the region overnight into Sunday
morning. A few rain and snow showers will accompany its passage.
A brisk day setting up for Sunday as a return to at least
partial sunshine. Another fast moving system may bring
accumulating snowfall south of I 90 overnight Sunday into Monday
.NEAR TERM /THROUGH SUNDAY/...
As of 1030 PM EDT, winds have increased to 15-20 mph with gusts
up to 35 mph. These winds will be sustained through the early
morning as temperatures stay fairly mild. That being said, no
major changes made as the forecast remains on track.
Prev Disc...As of 740 PM EDT, Cloud cover continues to increase
from west to east across the area this evening with
temperatures generally in the 40s to low 50s. Precipitation,
currently over western New York and northern Pennsylvania is
still working its way east, with mainly light rain being
reported. That being said, only made minor tweaks to the
forecast at this time, to align hourly temps with recent obs.
Sent updates to NDFD and web servers.
Prev Disc...As of 330 PM... A beautiful start to our weekend
with wall- to- wall sunshine, however, as seen in the enhanced
GOES 16 data the clouds will be on the increase from the west in
advance our next weather system. Rather strong cold front will
cross the region overnight as main surface low deepens and
tracks across the central Great Lakes and toward James Bay.
Upstream regional radar reveals an extensive area of showers
across the Great Lake State of Michigan with a break in the
coverage into Indiana and Ohio. Per the latest HRRR along the
analysis of the layer H2O vapor loop, the main center of the low
will become further removed from the front as mid level
moisture fields become increasingly drier overnight. This points
toward a decrease in PoPs/Wx overnight to scattered showers.
However, overall enhanced low level convergence and low level
jet with upper jet support would allow for showers to redevelop
over the region overnight. Hence our graduated PoP forecast with
the higher terrain the higher values than those in the Hudson
Valley. There could be another enhancement to the showers
southeast of Albany as the upper jet tracks northward with
enhanced low level ageostrophic lift for additional showers. As
for thermal profiles, cold advection quickly increases with
FROPA where some rain mixes with and changes to snow overnight
(again, mainly the higher terrain and west of the Hudson).
Accumulations should be an inch or less due to the fast movement
of these features.
Then some minor Lake Ontario response may occur Sunday morning
yet inversion levels are expected to drop as subsidence and
surface ridge builds in from the west. The main hazard potential
will be the increasing wind magnitudes through the morning
hours. Per BUFKIT hourly profiles at select points across the
region and hires wind gust potential, seems we will see wind
gusts just below the thresholds for wind advisory criteria.
Values will generally be in the the 30kt range which in
agreement with observations upstream per METARS. As H850
temperatures fall back below -10C, high temperatures will likely
be earlier in the day and with early April sun angle holding
temperatures nearly steady through the early afternoon.
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
Potential for an accumulating snowfall event south of Albany on
the increase overnight Sunday into Monday morning.
H2O vapor loop reveals a rather strong wave across the Pacific
northwest that will continue to track southeast across Idaho.
Models are now suggesting this wave will be a little further
north as downstream trough axis orientation will be more zonal
than amplified. The ECMWF was the first to suggest this
potential and the NCEP Model Suite appears to be trending
northward per the Dprog/Dt analysis. So clouds will increase
across the southern 2/3rds of the region Sunday night with light
snow developing from west to east overnight mainly south of I90.
Cross sections from the NAM/GFS point toward a tight 850-700 2D
FGEN fields near the I84 corridor. So a band of moderate
snowfall is possible and per the trends, did increase snowfall
amount forecast a bit from the previous forecast. At this time
time, 1-3" of snow with up to 4" possible along southern
Dutchess and Litchfield Counties. The snow should end rather
quickly around 15Z Monday as dry air advection occurs with
surface high building in across the region.
This surface high strengthens just to our east Monday night as
next storm system approaches from the west. This will increase
the cloud coverage from west to east yet again with the chance
for a light snow to develop late across most of eastern NY.
Temperatures through the short term will generally be at or below
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A Low pressure system over the mid western portion of the United
States will track north and eastward. As this system approaches the
region...it will bring widespread precipitation to the region late
Tuesday through Wednesday night. At this time...it may start out as
a mix of rain and snow as temperatures will be below freezing
initially. By Wednesday...warmer air will will move back into the
region keeping the precipitation in the form of rain.
Wednesday night...the low pressure system will continue to move
north and eastward. However...with wrap around flow from the
departing system...there may be the threat of rain showers changing
back over to snow showers. Any precip that does fall Wednesday
night will be light.
Thursday and Friday will be unsettled as another system drops down
from Canada. This will bring the threat of more precipitation and
cooler temperatures. With a cold air mass in place...will probably
see rain and snow mixed.
On Wednesday ahead of the storm systems cold front...temperatures
are expected to warm to seasonable levels with highs forecast in the
upper 40s to 50s. However with the passage of the cold front a
colder airmass returns with well below normal temperatures expected
Thursday. The end of the week could be blustery with a series of
systems dropping down from the north creating a tight pressure
gradient with strong winds and below normal temperatures.
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Clouds will continue to increase overnight as a low pressure
system with associated fronts approach from the Great Lake
region. The low pressure system will pass north of our region
with a warm frontal passage this evening, then a cold front by
Sunday morning. There is chance of light showers overnight with
the frontal passage. However, any precipitation that does fall
will be very light. Clouds should break up and lift across all
TAF sites by Sunday afternoon.
S-SW winds will gradually shift to the west by 12z/Sunday as a
cold front moves through the region. With a decent pressure
gradient in place, 10-20 kt sustained winds with gusts up to 35
kts are expected.
Prior to the cold frontal passage Sunday morning, some LLWS is
possible at KPSF.
Saturday Night: Moderate Operational Impact. Breezy. Scattered SHRA...SHSN.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
Monday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Tuesday: High Operational Impact. Likely RA...SN.
Tuesday Night: High Operational Impact. Likely RA.
Wednesday: High Operational Impact. Likely SHRA...RA.
Wind gusts over 25 mph are expected Sunday...
Scattered rain and snow showers are expected overnight into
Sunday morning as a strong cold front crosses the region. It
will turn breezy tonight and remain breezy on Easter Sunday with
cooler temperatures but mostly dry aside from lingering light
morning snow showers. Another round of light snow is possible
south of I-90 Sunday night into Monday morning.
Mild temps today may result in a little bit of snowmelt.
Scattered light showers are likely along an approaching cold
front tonight. QPF amounts less than 0.25 inches expected. Light
snow may fall above 1500 feet, especially over the southern
Adirondacks with around an inch possible. A colder airmass will
take hold Sunday into Monday, with limited snowmelt during the
day and subfreezing temps at night. A more widespread
precipitation event is likely for Tuesday into Wednesday. QPF
amounts could exceed an inch. This event is likely to be mainly
rain with fairly mild temperatures, but may begin as snow early
Tuesday, and may mix with snow toward the end of the event over
the higher terrain.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
Area Forecast Discussion
National Weather Service Denver/Boulder CO
820 PM MDT Sat Mar 31 2018
Issued at 802 PM MDT Sat Mar 31 2018
Areas of pcpn have developed over the plains from
Fort Morgan to Sterling and near the WY border. This
area is north of a frontal boundary and aligned with right
exit region of an upper level jet. Have adjusted pops a bit
further south to account for current trends. Late tonight
the upper level jet may sag further south as an upper level
disturbance moves across. This may allow for a chc of snow to
spread further south between 09z and 12z with the northern part of
the Denver metro area being affected and along the I-70 corridor
in the mtns.
.SHORT TERM...(This evening through Sunday)
Issued at 235 PM MDT Sat Mar 31 2018
Flow aloft is west-northwest as a shortwave trough over the
Pacific Northwest will be dropping southeast, crossing over the
Northern Rockies early Sunday morning. Moisture this afternoon has
been less than previously though, with little to no snow being
observed in the northern mountains. Most precipitation activity
is further north in Wyoming. Wind and temperature forecasts has
been difficult over the plains this afternoon as a cold front
hangs over the northeastern plains while a Denver Cyclone is
spinning up over Douglas County. Thinking is the cold front will
push in early this evening, but perhaps not as strong as
originally thought, with the Cyclone staying nearby which may keep
low clouds out of the western urban corridor, or at least not as
thick overnight. Latest forecast soundings have backed off
slightly on the amount/thickness of low clouds, but it still
remains. Therefore, for Easter Sunday morning, may have some low
clouds around sunrise and potentially for a few hours after, but
should break up by noon with sun shining in. The one exception
will be the far northeastern corner where the inversion will be
thicker and stronger. Temperatures Sunday will be similar to
For the shortwave passage overnight, trends in hi- res models
have been to shift this moisture further north, with the HRRR not
even wanting to bring precip into the plains, but with limited
amounts into the northern mountains. Will still have a chance to
likely chances over the far northern plains, but shift this area
slightly more to the north. Through Sunday morning, still
expecting 1 to almost 3 inches along the northern state border,
with 1 to 4 inches over the northern mountains north of I70 - some
higher areas could see up to 5 but this will be limited.
.LONG TERM...(Sunday night through Saturday)
Issued at 235 PM MDT Sat Mar 31 2018
The upcoming week will be characterized by a moderate to strong
northwest flow pattern along with several embedded disturbances to
move across Colorado. Before the first wave, there will be strong
westerly flow over the mountains Sunday night and Monday with
strong and gusty winds over the mountain passes. Some of these
winds will also surface over the plains by Monday afternoon with
breezy yet warm conditions in downslope flow. This does not appear
to be a significant high wind threat.
The first of the week`s waves and will move across Colorado on
Monday night and early Tuesday with shot of snow for the mountains
and lesser chances over the northeast plains. This will be a fast
moving system and any upslope will be short lived on the plains
as stronger northwest flow develops behind it. Best chances of
showers will be east of the Front Range. Drier and cooler on
Tuesday behind the wave and then warmer again on Wednesday with
dry northwest flow. The next wave later in the week is poised to
move over Colorado Thursday night and Friday with the next chance
for mountain snows and showers over the plains and cooler over all
areas on Friday.
Somewhat more unsettled over the weekend as stronger troughiness
develops over the Great Basin and spreads more moisture across
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 235 PM MDT Sat Mar 31 2018
Southeasterly winds currently over the airport, however a Denver
Cyclone setting up south of Denver should push east to bring
northwesterly winds over the terminals. There is a chance for the
southeasterly winds to remain to remain at DEN. VFR conditions
are expected through the rest of the day. A second surge of
northeast winds will occur this evening, by 02z with the potential
for ILS restrictions with cigs bkn around 5 kft agl around 06z,
then lowering to near 1 kft as the upslope deepens by 10z. Stratus
should then break up by 15-17z with VFR conditions and easterly
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 802 PM MDT Sat Mar 31 2018
Sfc low was over the Palmer Divide as nely winds continue at DIA.
Meanwhile stratus has advected into the area as well with ceilings
down to 2000 ft. Latest data suggest these lower ceilings may last
overnight thru sunrise. As for winds they will stay mostly east
or northeast overnight. Finally there is some risk of a brief
period of light snow late tonight between 10z and 13z which may
stay just to the north of DIA.
Issued at 235 PM MDT Sat Mar 31 2018
There is a potential for critical fire weather conditions Monday
afternoon and early evening as gusty southwest winds and low
humidities develop. Highest focus area will be over fire weather
zones (246..247) and includes eastern Elbert and Lincoln counties.
These areas have also only had limited rain/snowfall during the
Fire Weather Watch from Monday afternoon through Monday evening
Area Forecast Discussion
National Weather Service Billings MT
903 PM MDT Sat Mar 31 2018
Courtesy of a moist dendritic layer and weak ascent, areas of
light snow and flurries continue across our western cwa including
the Billings and Sheridan areas as of 830pm. Forcing is slowly
shifting south, with drying from the NW, so the light
precipitation should end soon, probably by around midnight. Only
other issue tonight is fog. Boundary layer is fairly dry in our
east where skies are clearing, and cloud cover will remain up in
our west, so not sure if we will realize our fog potential
tonight. With partial clearing we could see fog in valleys in our
central parts, areas that saw precip over the past day, and this
includes places like Roundup, Billings and Sheridan. Recent HRRR
runs are not suggestive of fog at all. Will make some adjustments
to the fog coverage later tonight into early Sunday. Something to
keep an eye on through the night. Otherwise, it will be COLD
tonight with a record low quite possible at Miles City (record is
4 above on April 1st). Be ready for a chilly Easter morning
.SHORT TERM...valid for Sun and Mon...
Snow showers were quickly winding down this afternoon as a
combination of drier air from the west, decreased upper level
support, and diminishing upslope flow moves in. It`s going to be a
very cold night across the forecast area with low temperatures in
the low teens and upper single digits. Can`t rule out some low
lying locations in eastern Montana seeing temperatures near or
just below zero (see Miles City forecast low of -1). Most roads
are clear of snow at this hour, thanks to our high sun angle this
time of year, but slick conditions are still possible into
tonight, especially as the sun begins to set and the roads quickly
cool. Last forecast concern for tonight will be the potential for
fog in eastern Montana as mostly clear skies and light winds
could allow patchy fog to develop overnight.
Quiet conditions anticipated Sunday along with warmer temperatures
in the upper 30s and low 40s. Eyes will be on the next winter
system to approach the region Sunday night. Precipitation will
begin to overspread the region Sunday night and Monday morning.
Any rain showers will turn to snow Monday morning as a upper
level low works into the region. This system, dynamically, is
different from Saturday`s system and is more typical of a spring
winter storm system. Expect a wet heavy snow to fill in across
the region Monday into Monday night with 4 to 6 inches of snow
possible over the lower elevations. The mountains will see more,
with 6 to 15 inches of snow possible through Tuesday morning.
Timing of this system, with the heaviest precipitation falling
during the day Monday, does leave some uncertainty in regards to
snow amounts. Accumulations this time of year can be hard to come
by during the day as a higher sun angle can limit accumulations
depending on the cloud cover, so its something to keep an eye on.
With these possibilities in mind have put out a winter storm watch
for Sunday night through Monday night across the entire forecast
.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...
Only trended the extended towards current model trends. Models did
not come in with any major changes. Monday`s trough will move out
Tuesday, so there should only be maybe some linger precip early in
the day. Flow through the period remains northwesterly, so cannot
rule out at least some slight chance PoPs through much of the
extended. The 12Z runs did some in a little wetter towards the end
of next week. The GFS is a little faster than the EC with the
precip. Temperatures still looks to be on the cool side. Reimer
Lingering areas of light snow and flurries should dissipate by
around 06z. Areas of MVFR ceilings along and west of a BIL-SHR
line should gradually improve to just VFR. Mountains will be
occasionally obscured tonight. There is a slight risk of patchy
valley fog later tonight into early Sunday, but confidence in fog
impacting a terminal is quite low. Will continue to monitor
through the night.
On Sunday, the next approaching disturbance will bring increased
chances of rain/snow showers west of BIL by afternoon. Expect
local MVFR and increasingly obscured mountains. JKL
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
BIL 011/042 027/035 013/037 022/043 028/044 026/041 026/046
11/B 77/W 52/S 12/R 24/O 54/O 43/O
LVM 011/047 031/038 015/040 025/048 031/050 029/047 031/051
13/W 87/W 52/O 23/O 36/R 75/R 44/R
HDN 008/042 027/035 012/037 019/043 026/043 023/041 022/045
10/B 68/J 62/S 11/B 24/O 55/S 43/O
MLS 901/037 024/030 010/031 016/038 022/037 018/033 019/039
00/B 67/J 72/S 11/B 34/O 33/S 33/S
4BQ 008/042 025/038 013/034 018/041 025/042 021/037 021/043
00/B 47/W 72/S 11/B 24/O 55/S 53/S
BHK 002/036 022/029 008/028 012/036 019/034 013/030 015/034
00/U 57/J 81/B 11/B 13/S 22/S 12/S
SHR 009/044 028/042 014/036 018/045 026/048 027/043 027/049
21/B 48/W 72/S 12/S 23/O 65/O 43/R
MT...Winter Storm Watch in effect from Sunday evening through
Monday evening FOR ZONES 28-29-34-35-39>42-56-63>68.
Winter Storm Watch in effect from late Sunday night through
late Monday night FOR ZONES 30>33-36>38-57-58.
WY...Winter Storm Watch in effect from late Sunday night through
late Monday night FOR ZONES 98-99.
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1154 PM EDT Sat Mar 31 2018
Fairly dense canopy of top of the mixed layer stratocumulus this
evening in the wake of the cold front that passed through all of
Southeast Michigan this evening. Initial cold advection in the
presence of high ambient moisture environment has led to saturation
below the established subsidence inversion. Really at odds tonight
with how quick clouds will scatter/move out as efficient, deep
column downglide is forecasted. Preference is to side with BKN-OVC
cloud early in the TAF forecast, giving way to SCT conditions by late
morning Sunday. However, note there is some uncertainty as clouds
could become emboldened again with diurnal heating. Look at the NAM3
output vs. RAP.
For DTW...Wind shift/fropa expected to occur right around 00z.
/DTW THRESHOLD PROBABILITIES...
* Medium to low for ceilings aob 5000 ft tonight through tonight.
Issued at 347 PM EDT Sat Mar 31 2018
The Wind Advisory will remain in effect as strong wind impacts
remain a concern during late afternoon and evening. After that,
conditions quickly improve overnight leading to a cold but otherwise
pleasant Easter Sunday.
Early afternoon wind gusts touched 45 mph in a few spots over
central Lower Michigan with the onset of rain, which also had a
stabilizing effect through mid afternoon. Incoming RAP model
soundings indicated a much shallower mixed layer as a result,
however observations do indicate some recovery taking place upstream
with several mid afternoon gusts in the upper 30 to lower 40 knot
range along the Illinois/Indiana border. This recovery is also
picked up by the rapid update model soundings depicting a deeper
mixed layer to neutral profile making northward progress into Lower
Michigan prior to the frontal passage. This leaves the door open for
gusts reaching 45 mph+ ahead of the front within and in between
shower activity. Surface temps and dewpoint reaching as high as the
mid 50s/mid 40s immediately ahead of the cold front also suggests we
monitor for an uptick in low-topped convection along the boundary
during late afternoon and early evening. This would also will be
capable of overachieving wind gusts, as will the frontal passage
itself. Isolated peak gusts reaching 50 mph+ remain possible until
the front exits SE Michigan 8-9 PM.
Northwest wind will continue Sunday morning but at much lower speed
and while backing toward the west as high pressure builds into the
southern Great Lakes. Model profiles still depict enough residual
boundary layer moisture and low level instability for pockets of
clouds and a few flurries as waning low level cold advection
combines with April 1st daytime heating. Forecast soundings do show
only shallow ice supersaturation along with cloud base on the high
side, near 5000 ft, and so coverage of flurries will be less than
indicated by radar. The incoming surface high will otherwise ensure
dry weather with partly sunny skies while cold air holds highs in
the 30s. There will also be precipitation nearby to the south as a
low pressure system moves through the Tennessee Valley, which is
shown in model data to spread a light mix of rain and snow as far
north as Toledo by Sunday evening. This will be monitored as
increasingly dry air in the low levels associated with the center of
high pressure moving over Lower Michigan is expected to prevent any
precipitation from moving north of the Ohio border.
Monday will start out the new week with high pressure centered over
the Ohio border region and remaining in control of conditions across
SE Michigan. A generous amount of early April sunshine will help
temperatures moderate into the lower and mid 40s before clouds
thicken late in the day. These clouds will be arriving ahead of the
next low pressure system, currently analyzed over the Canadian
Pacific coast, as it moves into the Plains and Midwest by Monday
night. This system is projected to spread precipitation northward
into the Great Lakes later Monday night into Tuesday. There remains
considerable spread in model opinion on the quality of moisture
supplied to the system which affects the depth of saturation and
associated guidance projections on precipitation type. Considering
that the low will interact with the frontal zone left behind over
the Tennessee Valley, the low should have access to adequate
moisture favoring deeper saturation profiles that would result in
snow at onset over Lower Michigan followed by a quick transition to
rain during Tuesday morning. A mixed precip window is possible early
Tuesday but will maintain a basic change from snow to rain for now
considering the brief nature of the transition.
The precipitation Monday night and Tuesday will occur in advance of
the low pressure system and then continue Tuesday night into
Wednesday as the low moves through the southern Great Lakes. At this
point, variability remains high in model solutions regarding the
surface low track and QPF amount/distribution. The NAM provides a
warmer solution for SE Michigan with a surface low position over
central Lake Huron by Tuesday evening. The ECMWF has the surface low
over NW Indiana by then, and is colder with much higher with QPF.
The going forecast favors a snow to rain to snow transition through
this time period for now with later updates providing some clarity
on timing and track of the system. This system will also mark the
transition to broad long wave trough in the upper levels over
central Canada and the Great Lakes that will last into next weekend
and keep temperatures well below normal through the period.
Low pressure is tracking through the Straights late this afternoon and
will continue to deepen as it tracks off to the northeast into Eastern
Canada. The associated cold front will sweep through the Central Great
Lakes early this evening, leading to a wind shift to the northwest. All
marine headlines have been continued. Although, the low is slightly
weaker than expected and could just see brief storm force winds over
northern Lake Huron vs 3 hours or greater. Otherwise, extended period
of gale force winds look good for the other marine waters. Post frontal
northwest winds tonight will slowly diminish and become westerly
tomorrow, with light winds to start the work week on Monday as high
pressure slides through. Another strong low pressure system will move
move into the area on Tuesday, with northeast winds of 25 to 30 knots
expected over Lake Huron. Gale force winds are not out of the question
of central Lake Huron, funneling into Saginaw Bay.
Lake Huron...Gale Warning until 4 AM EDT Sunday for LHZ363-421-422-441>443-
Storm Warning until 4 AM EDT Sunday for LHZ361-362.
Lake St Clair...Gale Warning until 4 AM EDT Sunday for LCZ460.
Michigan waters of Lake Erie...Gale Warning until 4 AM EDT Sunday for LEZ444.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Indianapolis IN
1022 PM EDT Sat Mar 31 2018
The AVIATION Section has been updated below.
Issued at 239 PM EDT Sat Mar 31 2018
Active weather will continue across Central Indiana the next
several days as multiple weather systems will pass through the
A cold front will sweep across Central Indiana late this
afternoon...leading to some rain showers late this afternoon and
early this evening. Sunday will start as a dry day as the front
lingers across south of Indiana...However...a quick moving upper
level weather disturbance will arrive in the area on late Sunday
Afternoon. This will bring chances for a rain/snow mix of
precipitation across Central Indiana on Sunday evening. Light
accumulations will be possible.
After dry weather on Monday with high pressure across the
area...a couple more weather systems will push through Central
Indiana on Monday night through Wednesday...bringing more chances
for rain and maybe even a few spring thunderstorms.
Other than Tuesday...look for temperatures to be mostly below
.NEAR TERM /Tonight/...
Issued at 239 PM EDT Sat Mar 31 2018
Surface analysis early this afternoon shows a strong area of low
pressure in place over NE Wisconsin with a trailing cold front
stretching SW across Western Illinois to Central Missouri and SE
Kansas. Radar shows a few light showers across Central Indiana
Ahead of the front stretching from Muncie to GreenCastle and
Terre Haute. Southerly surface flow was in place ahead of the
front. Water vapor imagery shows the quick W-NW flow in place
aloft across the region...showing a few weather systems upstream
poised to push across the Ohio Valley.
HRRR suggests the progression of the precipitation across the area
will shift slowly to the southern parts of the forecast area by
00Z...exiting southern parts of Central Indiana by midnight.
Models suggest that the elongated front will sag across southern
parts of the state this evening as the front become more E-W
oriented. This suggests that some of the ongoing precip currently
over Missouri and SRN Illinois should advect to the southern
parts of the forecast area this evening. Forecast soundings and
time heights suggest good moisture in place across the area with
some dynamics aloft still passing. Thus will focus best pops
across the far southern parts of the forecast area mainly during
the evening hours...much much lesser pops through the early
evening as one progresses north across the forecast area.
Given the expected cold air advection...will trend lows at or
below the forecast builder blends.
.SHORT TERM /Sunday through Tuesday/...
Issued at 239 PM EDT Sat Mar 31 2018
Another weather system looks to impact Central Indiana on Sunday
afternoon and evening. As the frontal boundary left over from
today`s system stalls across Kentucky...the GFS and NAM suggest
another short wave within the flow aloft to push across Ohio
valley. Forecast soundings respond to this feature with a
saturated column by late in the day on Sunday with Pwats near 0.65
inches. The GFS 295K Isentropic surface shows excellent
isentropic lift across the southern parts of Central Indiana with
specific humidities over 4 g/kg. forecast soundings also show
much of the column below freezing...all expect the far lowest
levels near the surface. Thus precip type...should mainly be snow
in the IND metro area...but perhaps a mix across far southern
Indiana where the above freezing layer will be a bit thicker. Will
include a mix at those locations. Nonetheless...given the forcing
and ample moisture...will trend to a light accumulating snow.
Evaporational cooling from ongoing precip will also help to cool
lower levels. THus will trend pops at or above the forecast
builder blend on Sunday afternoon and Sunday Evening....along with
Highs at or below the forecast builder blends.
Forcing and dynamics quickly exit the area overnight on Sunday
Night as isentropic lift is lost and subsidence resumes across the
area. Thus will trend pops toward a dry forecast overnight and
stick close to the forecast builder blends.
A pause between weather systems looks in storm for Monday Morning
and early monday afternoon as HIgh pressure quickly moves across
the area. Here forecast soundings show a dry column with
subsidence. Thus will trend toward partly cloudy for much of the
day. however by late afternoon the forecast soundings start
trending toward saturation as a warm front approaches from the
south...and yet another low pressure system begins to spin up
over the central plains. Aloft...but the models do show limited
forcing on Monday afternoon...appearing weak. Better lower level
organization arrives on Monday night as the warm front lifts
north across Central Indiana. Thus will focus best pops across the
The warm front to the north places Indiana clearly in the warm
sector briefly on Tuesday. Model suggest strong low pressure on
Tuesday sweeping from Illinois to toward Lake Huron. THis will
drag another strong cold front across Central Indiana...with
ample dynamics. Again forecast sounding here show deep saturation
with some potential for some elevated convection. Given this
favorable set-up will again include high pops on
Tuesday...particularly during the afternoon hours during the
expected frontal passage.
.LONG TERM /Tuesday Night through Saturday/...
Issued at 325 PM EDT Sat Mar 31 2018
Guidance suggests a couple of different systems will impact the area
during the long term period - the first, the tail end of the frontal
system that will bring rainfall to the area early in the week, and
the next, another cold front late in the week. Temperatures,
particularly late in the week, will be borderline and may support
some periods of light snow showers, although this is low confidence.
Temperatures will generally be below normal throughout the long term
with a couple of reinforcing shots of cooler air.
Blended initialization handled things well and only minor
adjustments were required.
.AVIATION /Discussion for the 01/03Z TAF Update/...
Issued at 1021 PM EDT Sat Mar 31 2018
Removed gusts from KIND.
The gusty southwest winds have begun to taper off and will
continue to do so over the next few hours. Meanwhile, current
radar mosaic shows rain showers mainly concentrated over KBMG,
ending there after Sun 06Z as well. Conditions will fluctuate
around the MVFR/VFR mark through Sun 03Z, then becoming primarily
VFR through the end of the TAF period. Winds will become northerly
early tonight at 5 to 10 kts.
Area Forecast Discussion
National Weather Service Jacksonville FL
929 PM EDT Sat Mar 31 2018
...PATCHY FOG AND LOW CLOUDS DEVELOP TONIGHT...
Coastal Trof is setting up over the Atlc Coastal Waters with a few
showers there, while the cool/moist N-NE flow over the land areas
will set the stage for low clouds and patchy fog development
tonight. High clouds have pushed SE of the region so many areas
will be mostly clear/partly cloudy until clouds develop later
tonight. Models still unsure of how thick any fog would get
towards morning with latest 15z SREF run showing just patchy 3-5
mile fog, while the latest 23z HRRR is hinting towards morning
patchy dense fog development around sunrise with local vsbys below
1 mile in some locations. Will depend on position of coastal trof
and how much the N-NE winds weaken towards morning, for now they
seem to holding in the 5-10 mph range and expected to decrease to
around 5 mph towards morning, while any decrease to near calm
winds will support some local dense fog. Temps expected to fall
near 50 degrees across inland SE GA/Suwannee Valley with rest of
the area falling into the 50s. On Sunday, low clouds/patchy fog
slow to disperse in the morning hours, but overall expect at least
partly to mostly sunny conds by the afternoon with light winds and
local sea breezes along the coast. Temps should push to near 80
degrees over inland areas while sea breeze along the coast will
hold max temps in the lower/middle 70s. Moisture from old frontal
boundary may lift northward enough to trigger a few widely
scattered showers along the Atlc sea breeze as it moves inland
from JAX southward along the St Johns River Basin, but chances
still remain fairly low at 20% or less for now.
MVFR CIGS have already developed at CRG/SGJ along the NE FL Atlc
Coast and these will spread inland and northward with widespread
MVFR CIGS by 06z then lowering to IFR CIGS by 09z with some patchy
4-6 mile vsbys possible as well. Some Hi-Res guidance suggesting
even lower LIFR CIGS/VSBYS in the 09-15z time frame but for now
just gone with IFR conds. These will slowly lift/improve into MVFR
CIGS by 14-15z and VFR conds by 18z Sunday.
Coastal Trof setting up over the offshore waters and will continue
at least N-NE winds 10-15 knots across the local waters with seas
lingering in the 4-6 ft range tonight with SCEC headlines. NE
winds will weaken slightly on Sunday with local sea breezes at the
coast and seas falling into the 3-5 ft range.
Rip Currents: Moderate Risk in the onshore flow.
.PRELIMINARY POINT TEMPS/POPS...
AMG 47 82 54 84 / 0 0 0 0
SSI 56 70 57 77 / 0 0 0 0
JAX 53 77 56 82 / 10 0 10 10
SGJ 58 73 57 78 / 10 10 10 10
GNV 53 81 56 83 / 0 10 10 10
OCF 56 82 57 83 / 0 20 20 10
Area Forecast Discussion
National Weather Service Paducah KY
634 PM CDT Sat Mar 31 2018
Issued at 634 PM CDT Sat Mar 31 2018
The AVIATION section has been updated for the 00Z TAF issuance.
.SHORT TERM...(Tonight through Monday night)
Issued at 320 PM CDT Sat Mar 31 2018
Showers continue to spread east into the area while increasing in
coverage. The RAP model continues to show increasing elevated
instability seen via steepening mid level lapse rates and computed
li`s aoa 800mb below zero into SEMO, far west KY, and perhaps the
southern tip of Illinois. Will continue with high PoPs for showers
and a couple of thunderstorms as the front moves south across the
region tonight. Highest QPF should be across the southern 1/2 of
Looks like a lull in the precipitation Easter morning, with the
front to our south and little upper support. Clouds will likely
hang around. During the afternoon, forcing aloft moves toward the
area in conjunction with a s/wv that should be over the Upper
Midwest by 00z Monday. Generally liquid precip through the end of
the day. We`ll keep a look out across the far NW counties of
SEMO/Southern IL late day and into the evening. First time frame
of interest is 00z-06z, as we may see a light wintry mix north of
a Marble Hill MO, to Mount Carmel IL line. However temperatures
will generally be at or just above freezing. So essentially no
impact. After 06z, we lose moisture aloft for any ice nucleation.
Temperatures close to and north of the aforementioned line fall
below freezing. So any lingering low level moisture that might
result in light freezing drizzle or very light rain could freeze.
It`s very borderline at this time. The NAM is about a degree
warmer than the GFS. Not really worth of much more than a mention
in the Hazardous Weather Outlook at this point. It is something to
keep an eye on though.
Return flow sets up Monday. Again a bit of a lull Monday morning,
followed by increasing shower chances in the afternoon from west
to east. Maybe some thunder too. Shower and thunderstorm chances
ramp up Monday night as the warm sector becomes better established
across the region. Best chance PoPs Monday night should be across
the northern 2/3 of the CWFA.
.LONG TERM...(Tuesday through Saturday)
Issued at 320 PM CDT Sat Mar 31 2018
The medium range deterministic models were in reasonably good
agreement on the active, fast pattern in the extended forecast
After daybreak Tue, though clouds may be quite plentiful,
indications are that the trop could destabilize enough for some
robust convection, given the amount of bulk shear available and
forecast temps in the upper 60s and lower 70s. By midday or so,
scattered clusters or lines of tstms are expected to develop across
the entire region. Severe thunderstorms are a possibility, with
damaging winds and large hail the primary concerns. It will be
breezy ahead of a cold front, with southwest winds 15 to 20 mph,
gusting to 25 to 30 mph. Fropa will begin in the northwestern
counties around nightfall, and the fast-moving cold front may be
through the entire region by midnight. A few showers may linger in
the Pennyrile region of KY after midnight.
High surface pressure will rule the forecast picture for our region
midweek. Under mostly clear skies, temps are progged to crash back
to the upper 40s to lower 50s for highs Wed and near or just below
freezing Wed night, which may be a concern for growers of early
spring vegetation especially in the southern half of the region.
Southerly winds on the backside of the high will assist with a
modest warm up ahead of a substantial system later in the week. As a
low pressure system over Hudson Bay finally rotates into the
vicinity of the Great Lakes, substantial height falls are forecast
across the eastern CONUS. By early Fri, clouds will be on the
increase in our region, along with coverage of showers, though the
12Z ECMWF came initially drier, starting the pcpn 6-12 hours later
than the other models. Fropa is forecast Fri afternoon, and it
appears most pcpn will be post-frontal. It will probably end with a
light wintry mix early Sat.
Issued at 634 PM CDT Sat Mar 31 2018
One area of showers will push eastward out of KCGI and possibly
KPAH early this evening, but will linger at the other sites
through the evening. As a cold front approaches later this evening
MVFR ceilings are expected to develop along with MVFR showers
that are expected to become widespread. Brief IFR conditions
cannot be ruled out. The cold front will move through the TAF
sites 04Z-07Z and north wind will become gusty at KCGI and to a
lesser extent at KPAH. The band of showers will move south out of
the TAF sites before daybreak. MVFR ceilings will linger through
the day in the south, but VFR conditions are expected fairly after
the rain quits in the northeast. Another area of rain will spread
north over the region in the afternoon.
Area Forecast Discussion
National Weather Service Blacksburg VA
850 PM EDT Sat Mar 31 2018
A cold front will approach from the northwest tonight before
sliding southeast across the area Sunday, and into North
Carolina by Monday morning behind a passing wave of low
pressure to the north. This front works back north as a warm
front Monday night into Tuesday in advance of a strong cold
front that looks to cross the region from the west on Wednesday.
High pressure follows the front with drier and cooler weather
for late week.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 845 PM EDT Saturday...
Very dry air remains in place across the region this evening as
seen via evening soundings and surface dewpoints that remain in
the teens and 20s. Satellite showing upstream clouds ahead of
the cold front to the west gradually approaching but fading upon
encountering the residual ridging in place. Latest guidance
indicates mainly increasing mid/high clouds through midnight
with moisture deepening somewhat by daybreak. However models
including the HRRR hold back most of the scattered showers
across the far northwest until just before 12Z. Thus delayed
pops a few hours overnight with low chances by dawn far west and
mainly increasing clouds elsewhere. Dropped lows again in spots
given only thin cirrus to start and dry air, which combined
with less wind in the valleys should allow some 30s overnight
with low/mid 40s elsewhere.
Previous discussion as of 248 PM EDT Saturday...
Going to see increasing clouds late tonight ahead of a weak front.
Models are showing limited eastern extent to shower threat late
tonight and Sunday as westerly flow will be cause a drying effect to
the lee of the Central Appalachians, so maintaining high chance to
low likelys over the western slopes of Southeast WV, to slight to
low chance pops as far east as the Blue Ridge.
Expect temps tonight to stay warmer than Saturday mornings, with
lows in the 40s, with possibly some upper 30s in the NC mountains.
Sunday will be will be a bit cloudier, especially in the mountains,
with some sunshine at times expect east of the Blue Ridge.
Temperatures will warm to the lower to mid 50s in the Southeast WV
mountains, to upper 50s to around 60 across the mountains, with mid
60s to around 70 from Roanoke east to the piedmonts of VA/NC.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
As of 300 PM EDT Sunday...
A weak mid-level disturbance tracking east in zonal flow is expected
to form a surface reflection along a washout frontal boundary draped
across North Carolina. Majority of the lift and moisture will reside
with the mid-level disturbance, bringing a chance for light rain to
areas north of hwy 460 and moderate rain chances north of I-64
Sunday night. Both waves track off the mid Atlantic coast Monday
A weak cold front will slowly move across the area Monday behind the
exiting disturbance. Light rain showers are possible Monday morning
north of hwy 460, then south during the afternoon. A weak shallow
wedge of high pressure will follow the front. A warm front aloft
will overrun the area Monday night, keeping light rain, drizzle, low
clouds and fog in the area into Tuesday. Pressure fall to the north
will break the wedge by late afternoon Tuesday.
With a frontal passage and a shallow dirty wedge providing abundant
cloud cover and rain to the region Sunday night through Monday
night, afternoon temperatures will be cooler than normal with
overnight temperatures being slight warmer than normal. Areas that
see the wedge erode Tuesday, such as the foothills and mountains,
should see temperatures warm into the lower 70s. If the wedge holds
over the piedmont through the afternoon, temperatures may get stuck
in the 60s. However, it looks like the wedge will break before
sunset, sending piedmont temperatures into the mid 70s.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 230 PM EDT Sunday...
An upper level trough over the Great Lakes will send a strong cold
front across the region Wednesday. The GFS has this front quickly
moving across the region Wednesday morning. Strong dynamics and
elevated PWATS could bring heavy rain into the region, however
thunderstorms-severe threat is low with the frontal passage occuring
during non-peaking heating hours. The ECM is slower with showers
coming across the mountains in the morning, then over the foothills
and piedmont in the afternoon. If cloud cover does not impede
heating, the chance for thunderstorms and severe weather is elevated
east of the Blue Ridge. High pressure builds in behind the front
Wednesday night and hangs around through Friday. The next chance for
rain will be Saturday with another strong frontal passage.
Temperatures will run 5F-10F cooler normal through the period.
Wednesday night into Thursday morning, temperatures will drop below
freezing. Other nights will remain cool with the possibilities of
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 700 PM EDT Saturday...
VFR conditions are expected to prevail tonight into early Sunday
under high pressure. A cold front will be approaching the
region from the northwest late tonight which will bring
high/mid clouds into the area overnight with cigs lowering by
Sunday morning. Some small possibilities do exist for stray
showers in the mountains overnight into tomorrow morning,
however probability is low enough that they will not be
advertised in the TAFs at this time. Expect cigs to remain VFR
east of the mountains Sunday afternoon but lower to perhaps MVFR
levels at KBLF/KLWB by mid to late afternoon. Still appears any
showers to remain across the far west but not enough to include
mention in the TAFS attm. West to southwest winds may again
pick up just ahead and espcly behind the front later Sunday
with gusts of 15-25 kts possible mainly along/west of the Blue
The front will cross the region from the northwest late Sunday
into Sunday night. Low pressure riding along the boundary will
likely result in sub-VFR cigs and vsbys in rainfall across at
least northern sections while KDAN may stay south of the lower
cigs/rainfall. There is a chance of snow or mixed winter
precipitation just north of KLWB Sunday night where more in the
way of IFR may occur.
Extended Aviation Discussion...
Low clouds, fog, and a few rain showers or drizzle may linger
into Monday ahead of a warm front lifting by to the northwest.
Tuesday still is questionable but appears improving flying
conditions in order behind a passing warm front with any
leftover lower cigs/drizzle giving way to VFR under increasing
southwest flow by afternoon. Another potent cold front crosses
the region Wednesday with widespread sub-VFR in showers likely.
A few thunderstorms may also occur with this stronger midweek
front. High pressure follows with a return to widespread VFR on
Area Forecast Discussion
National Weather Service Shreveport LA
932 PM CDT Sat Mar 31 2018
Weak shortwave energy aloft and an associated cold front at the
surface continues to make slow but steady progress south and east
across Southern Oklahoma late this evening. There is enough lift
aloft and frontal forcing for the development of showers and
thunderstorms along this frontal boundary during the last couple
hours across Central and Southern Oklahoma extending north and
east into Northwest Arkansas. 00z NAM output along with current
HRRR suggests that this boundary will continue a slow but steady
movement into our extreme northern zones by 12z Sun with the
possibility of scattered to numerous showers and thunderstorms
moving into these zones later tonight and into the morning hours
Sunday. The current forecast has a good handle on this
IR Imagery showing thin high clouds continue to blanket our region
this evening with progs showing the development of lower cloud
cover encompassing all but our extreme eastern zones after
midnight as well. Thus given the pressure gradient in place and
the continued southerly winds, do not think temperatures will fall
nearly as low as they fell last night. Current forecast suggest
another 5-10 degree temperature drop overnight, a little more
across our eastern zones which again is in the ballpark.
Therefore, no additional changes to the forecast are necessary
.PREV DISCUSSION... /issued 757 PM CDT Sat Mar 31 2018/
For the ArkLaTex VFR with some low and mid clouds over OK movg SE.
In addition, overnight stratus is expected toward daybreak and
will affect all terminals until mid to late morning. Some showers
will edge SE out of OK into near KTXK by 12Z. Light SE winds
overnight will pick up to 10KT from S/SW. Climb winds are S/SW
20-30KT to FZL 11.6kft and then W/NW 30-50KT for flight levels.
Outlook is for little change into Monday and fropa late Tuesday.
.PRELIMINARY POINT TEMPS/POPS...
SHV 59 78 60 78 / 10 10 20 10
MLU 55 79 57 78 / 10 10 10 10
DEQ 57 71 49 64 / 50 60 50 40
TXK 58 74 53 73 / 20 30 40 20
ELD 56 76 55 75 / 10 10 20 10
TYR 60 79 54 76 / 10 10 30 20
GGG 59 79 59 77 / 10 10 20 20
LFK 60 82 62 79 / 10 10 20 10