Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/02/23

AREA FORECAST DISCUSSION

National Weather Service Bismarck ND

 1029 PM CDT Sat Apr 1 2023

.UPDATE...
Issued at 1013 PM CDT Sat Apr 1 2023

We issued a SPS to highlight the potential for freezing rain
tonight over western and central ND. Latest HREF shows the
potential for freezing rain over mainly northwest ND from 06-09
UTC. From 09-12 UTC the potential does extend down farther south
as precip approaches the Highway 83 corridor, to around Bismarck,
then lifts northeast 12-15 UTC. The qpf is quite light over
central ND, south of the Highway 200 corridor, and Pops here are
also 20-30 percent, so the probability of freezing rain looks
better along and north of the Highway 2 corridor. Looking at
Bufkit soundings, HRRR and RAP soundings indicate 1-2 hours or
fzra potential on the leading edge of the precipitation as it
moves across the forecast area, then a changeover to snow. The
question remains then, will there actually be accumulating rain
within that window where the sounding supports freezing rain,
before the changeover to rain/snow occurs. The higher qpf amounts
in the far north would suggest that this would be the area to see
the best chances for freezing rain, but as we all know, even if we
get a quick shot of freezing rain farther south, it can quickly
cause travel hazards. We settled on a SPS for now to get the word
out for the potential for freezing rain, but thought there was
enough uncertainty at this time to hold off on an Advisory.

We made some minor adjustments to pops based on the latest short
term guidance. Otherwise no changes to the going forecast. No
changes either to the Wind Advisory issued earlier this evening.

UPDATE Issued at 842 PM CDT Sat Apr 1 2023

Based on latest guidance we issued a Wind Advisory for west
central and southwest North Dakota for late Sunday morning through
Sunday afternoon MDT. A warm front/occluded front moves through
most of the forecast area tonight, and is situated over eastern ND
Sunday morning. Meanwhile a tight pressure gradient sets up over
western ND Sunday within the dry sector of a nearly stacked system
near the Turtle Mountains. During the afternoon, we see steep
lapse rates develop south and west of Lake Sakakawea and the
Missouri River with strong winds of 40 to 50 knots at the top of
the mixed layer. The main uncertainty is how well these winds mix
down with our deepening snowpack as you move from the southwest,
towards the River. At this time we kept the Advisory over the
western tier of counties, where the snowpack has been the most
depleted. Later shifts can adjust as needed but this looks to be
a good start. NAM Bufkit soundings are the most meager while the
GFS and even moreso the RAP soundings indicate Advisory level
winds possible, mostly during the afternoon hours. Updated text
products will be transmitted shortly.

UPDATE Issued at 625 PM CDT Sat Apr 1 2023

No significant changes for the early evening update. Shower
activity, and even some scattered thunderstorms is pushing through
central Montana at this time. Latest update from CAMS show
precipitation developing ahead of this line over northeast Montana
this evening and moving into the west by late evening. Current
timing has changed little from this afternoon. Main question will
be how temperatures at the surface and aloft drop this evening.
Current guidance suggests only a short duration as precip
transitions from rain to snow. Will need to keep an eye on this as
things develop through the evening.

&&

.SHORT TERM...(This Evening through Sunday)
Issued at 227 PM CDT Sat Apr 1 2023

Warmer temperatures this weekend with a wintry mix tonight across
the north.

An upper level wave is currently moving through Montana and will
move through North Dakota tonight. This will bring a wintry mix
across the north since the daytime highs are in the upper 30s
today, and temperatures in the upper 20s and lower 30s when the
wave moves through. 1-2 inches are possible north of Highway 2, with
a slight chance of freezing rain along and north of the Missouri
River and Highway 200. We reduced the chance of freezing rain down
to a slight chance because most model soundings have the
temperature profile quickly saturating and turning from rain to
snow. Winds overnight will turn westerly and will be breezy
through all of Sunday. This west downslope wind from Montana will
aid temperatures climbing to the mid 30s east to mid 40s west. It
could also create patchy blowing snow, however with above freezing
temperatures today, the snow may be crusted over too much to
actually create issues.

.LONG TERM...(Sunday Night through Saturday)
Issued at 227 PM CDT Sat Apr 1 2023

Temperatures will be slightly cooler on Monday with quasi-zonal
flow and a surface high pressure to our north. Our attention now
turns to the Colorado Low Tuesday-Thursday. The latest trend in
the models today has been a slight western shift. On the cluster
analysis, all 3 clusters has moved slightly west. This created
more confidence in the system and the chance of higher snow
amounts. The NBM probabilities of the high end snowfall has
increased as well. We are still 4 days out however but we have
enough confidence for a Winter Storm Watch that will probably be
issued within the next 24 hours for the southeast to start with.
The other concern is it could be very windy across the James River
Valley Tuesday night through Wednesday as snow is falling. This
would create big impacts, especially for those wanting to travel
this upcoming holiday weekend.

Temperatures through the week will drop as the Low brings in
cooler temperatures, the end of the week could see the warm
temperatures again (closer to average), but may depend on how much
snow falls.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1013 PM CDT Sat Apr 1 2023

A band of precipitation moves through the area tonight bringing
light precipitation to the Northern TAF sites. Southerly winds
this evening shift westerly from west to east late tonight and
sunday and becoming gusty 20 to 35kts Sunday afternoon. At this
time it looks like only a brief period of MVFR cigs/vsby at KXWA
and KMOT (if any) tonight into Sunday morning. KXWA looks to be
the most likely area for rain/freezing rain with only a brief
period of rain and snow at Minot. MVFR ceilings then drop south
into KXWA and KMOT late in the TAF period.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from noon CDT /11 AM MDT/ to 7 PM CDT /6 PM MDT/
Sunday for NDZ017-018-031>033-040-041-043-044.

&&

$$

UPDATE...TWH
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...TWH



Area Forecast Discussion

National Weather Service Grand Forks ND

 722 PM CDT Sat Apr 1 2023

.UPDATE...
Issued at 710 PM CDT Sat Apr 1 2023

Water vapor satellite imagery reveal Sunday`s clipper centered
near the international border departing the Rockies headed due
east. This matches guidance nicely, reaffirming the thought of
wintry mix near the warm front out of the west and southwest
Sunday morning followed by clearing, warming, and increasing
westerly winds in its "warm sector" for the daytime Sunday
followed by cold front as the clipper departs which should
introduce some snow showers. There remains the possibility the
circulation could track and evolve in such a way where light snow
is experienced much of Sunday near the international border. Still
thinking up to 3 to 4 inches will be possible in our northern tier
of counties, along with a glaze of ice before 9 AM Sunday.

A note on tomorrow`s temperatures: clouds are expected to clear
along with winds out of the west-southwest over the Valley within
the clipper`s warm sector. This regime has a track record of
overachieving on temps within the Valley. Thus current
temperature forecast for Sunday may be too low, especially south
of US Highway 2 with temps nearing 40 not out of the question.
Should temps reach this high along with sunshine and breezy dry
winds, this could work at our snowpack some. It won`t melt it
completely by any means, but it may ripen and shrink its depth
some.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 224 PM CDT Sat Apr 1 2023

Key Messages:

-Quiet today, with below average temperatures continuing. Chance for
blowing/drifting snow later today into tonight.

-System moves in Tonight into Sunday bringing chances for snow,
mixed precipitation, and possible freezing rain I-94 northward.
Blowing/drifting snow will be possible behind the system.

-Impacts are possible from mixed precipitation/freezing rain Sunday
morning and blowing/drifting snow Sunday afternoon/evening creating
hazardous travel.

Rest of Today:

Skies remain mostly sunny across the area, with a few higher level
clouds expected to move into eastern ND throughout the afternoon and
evening hours. Guidance struggles to handle the temperatures today.
Went higher on temps using the 90th percentile for the valley. Highs
are expected to reach the mid to upper 20s, with some isolated 30s
in the valley. Outside of the valley towards central MN, highs could
reach the mid to upper 30s.

Tight pressure gradients ahead of an approaching system out of
southern Canada and steep lapse rates bring increased winds during
the evening and overnight hours for the northern Red River Valley
into the Devils Lake Basin. Some patchy blowing/drifting snow will
be possible creating reduced visibilities at times in open country.
Drifting snow could create some blow ice concerns overnight when
temperatures drop into the teens. This could create some minor
impacts at times overnight for areas along and north of Hwy 200.

Sunday into Monday morning:

An approaching system shifts its way into the northern plains Sunday
bringing strong mid level warm air advection to the region. Some of
this warm air is expected to reach the surface layer, with highs in
the mid to upper 30s within the valley. Areas towards northern MN
could see the low to mid 40s. As the warm front shifts west to east
across the area, precipitation chances increase along and north of I-
94. Snow, mixed precipitation, and the potential for freezing rain
are all possible Sunday.

Short range guidance (HRRR/NAM) continues to have the short wave
shift along the international border throughout Sunday and into
Sunday night. Start time still looks to be early on Sunday, with
strong WAA within the mid levels creating a warm nose under a large
amount of saturation in the low to upper levels. Mixed precipitation
with freezing rain is possible ahead of the system. This would be
tied to the warm front passage. Areas affected are medium in
confidence as a slight trend south has been noted in latest guidance
from the HRRR and NAM. None the less I-94 points northward has the
potential to see this mixed precipitation and freezing rain during
the morning hours before the inversion aloft begins to weaken late
morning. A glaze of ice to a couple hundredths are possible with any
mixed precipitation or freezing rain that moves through. There is a
potential (20-30% chance) to see up to 0.10 inches of ice in some
isolated locations near the Devils Lake Basin. Any area that sees
mixed precipitation and freezing rain will see impacts to travel
on untreated surfaces. Hazardous travel will be possible with any
ice accumulation.

A gradual transition to snow is expected near the International
border towards Highway 2 by late Sunday morning into the afternoon
hours as the warm nose decreases. Best chances for snow lies right
along the border towards the Turtle mountains. This is where the
frontogentic forcing and Synoptic forcing line up well with one
another in multiple short range models. Areas along the
International border could see up to an inch of new snowfall, with
isolated areas seeing up to 3 inches with any potential moderate
snowfall rates thanks to the frontogentic nature of the system.
Winds will be on the increase as the snow shifts east, with gusts up
to 40mph possible in eastern ND. Patchy blowing and drifting snow
will be possible during the afternoon and evening hours Sunday.
Areas where falling snow combines with strong winds will see reduced
visibilities in and out of urbanized centers. Impacts are looking
possible on Sunday from mixed precipitation in the morning, and
blowing/drifting snow chances in the afternoon and evening.

Winds continue to be breezy Monday morning, with morning lows in the
teens to lower 20s. Quiet conditions ensue behind the system, with a
a more significant system approaching Tuesday into Wednesday
potentially bringing significant to extreme impacts to the northern
plains. See Long Term section for further details.

.LONG TERM...(Monday through Saturday)
Issued at 224 PM CDT Sat Apr 1 2023

Overview: High impact storm between Tuesday until Thursday
morning. Heavy snow accumulations are anticipated for much of the
region. Warm temperatures and calmer weather pattern Friday into
the weekend.

Discussion:

Monday some lingering snowfall along the Canadian Border as the
upper low passes over and continues to wobble along our border.
Temperatures in the 20`s and 30`s are expected during the day.

Tuesday-Thursday (winter storm): A substantial Colorado ejects from
the rockies and heads directly for our region. The global models and
ensembles are in a general consensus about the strength of the storm
and the potential significant to extreme impacts. The global models
depict upper level divergence from 850mb-500mb to support synoptic
lift for our region. Looking at the 0z and 12z 925mb-850mb moisture
transport there`s a little uncertainty with how much moisture will
make it into the system. The forecasted 6-hour QPF runs between 0.35-
0.6 inches between the globals and ensembles. The Grand ensemble is
depicting a 50% probability of the 0.6 to 1.2 inches for QPF amounts
for the system. The GEFS and ECMWF still retain varied amounts of
accumulating snow between 6-15 inches. The LREF shows approximately
equal chances of occurrence(~20%) for the same amounts. The global
models also slightly vary between model runs and with each other on
where to place the greatest band of warm air advection and embedded
FGEN within the system to nail down the heaviest snowband. Looking
at the GEMPAK there also seems to be a delay in timing between the
vorticity advection and the moisture advection which also slightly
raises the uncertainty in accumulations above 15 inches. The NBM
paints a lovely 60% probability of exceeding 12inches across the CWA
by 00z Thursday (Wednesday afternoon). To further compliment this
large snow amount the forecasted winds look to be a sustained 25-35
with gusts up to 45 mph for tuesday and Wednesday. Probabilities
of exceeding 6 inches are over 80%, while exceeding 12 inches are
60%. While total snow accumulations can`t be nailed down yet as
they are being further resolved. It is with high certainty that
this will be a high impact event that will depart our CWA around
Thursday morning.

Friday into the weekend: A ridge slowly starts to fill in behind the
trough. Temperatures will rise to the low to mid 30`s after the
winter storm and hopefully to start our slow melting cycle and
finally say Spring is here.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 710 PM CDT Sat Apr 1 2023

VFR conditions prevail through at least 09 UTC across the region.
After 09 UTC, a clipper system moves through from the west
increasing winds from the west-southwest, bringing a chance for
light snow and wintry mix, and lowered CIGs into the IFR and MVFR
categories at times. Additionally, some LLWS will be possible
after 15 UTC Sunday, especially over southeast North Dakota into
west-central Minnesota.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

UPDATE...CJ
SHORT TERM...Spender
LONG TERM...MM
AVIATION...CJ



Area Forecast Discussion

National Weather Service Goodland KS

 950 PM MDT Sat Apr 1 2023

.UPDATE...
Issued at 825 PM MDT Sat Apr 1 2023

Todays Red Flag Warning was allowed to expire on time.

A Fire Weather Watch is in effect Sunday afternoon and evening for
Cheyenne and Kit Carson counties of Colorado. I have some concerns
regarding whether or not to upgrade to a warning at present time.
The biggest one is the presence of mountain wave cirrus clouds per
various models 300mb relative humidity forecasts and HRRR showing
at least 90% high-level cloud cover over parts of the area
including the Fire Weather Watch area during time of peak heating.
Not only could this impact the high temperature forecast which is
one component of the relative humidity forecast but could also
prevent full mixing of the wind which would produce lower wind
speeds then currently advertised. For those reasons, will let the
mid shift make the call on upgrading to a Red Flag Warning or
canceling the watch.

Otherwise, did some tweaks to the grids through Sunday night,
nothing significant.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 248 PM MDT Sat Apr 1 2023

Across the Tri State region this afternoon, sunny skies area-wide
persist on decent southwesterly flow, providing above normal
temperatures to the entire region.

Conditions will persist through the remainder of the afternoon
hours, with winds slackening into sunset. Models shift the trough to
the west to the south of the cwa. The result will be a shift from
southwest to southeast flow gradient remains tight over south-
southwest zones. Lack of qpf/low level moisture will keep RH levels
low across areas south of the Interstate. Most areas are close to
Red Flag criteria, but at this time have put in Kit Carson and
Cheyenne counties in Colorado. Please refer to the Fire Wx section
below or the latest fire weather product for more information. Any
shift/setup of the system to our west, will force the areal coverage
of the wind/rh to shift.

Similar conditions on track for portions of the region Monday
afternoon, but not enough of Colorado zone coverage will fall into
criteria, so have left the cwa out of any fire wx product issuance
at this time. Newer guidance may change this.

By Monday night and on through Tuesday, guidance brings a surface
low along the KS/NE border with the upper support well into
Nebraska. Best/deepest moisture will lie north of the cwa, but wrap-
around moisture will south into areas along/north of Highway 36. Low
qpf and expected temp trend will bring a light rain to light snow
scenario, with little to no accum. Best chance at this time will be
in portions of Yuma and Dundy counties.

While there will be little qpf with this system, a strong northerly
gradient will impact the region. Areas along the Nebraska border
could see 45-55 mph gusts, tapering off southward to at least 30-40
mph through the Interstate. These winds, combined with expected
snowfall will bring some patchy blowing snow in spots.

For temps, 60s and 70s for highs Sunday, will give way to 50s and
60s Monday, trending lower Tuesday as colder air arrives with 30s
and 40s west up to the 50s and 60s east. Overnight lows tonight in
the 30s will trend to the upper 20s west to near 40F by Monday
night.

.LONG TERM...(Tuesday night through Saturday)
Issued at 149 PM MDT Sat Apr 1 2023

00Z Wednesday the upper level low is situated over Nebraska, with
flow aloft briefly becoming west-northwesterly as the low pulls away
to the northeast before returning southwesterly ahead of the back of
the trough swinging through. An upper level ridge is moving into the
western CONUS around the Thursday timeframe with an upper level low
near southern CA/Baja California Thursday evening-night. Decent
disagreement model to model and run to run begins to appear around
Thursday-Friday onward so will continue to monitor for greater
consistency.

Down to the surface at 00Z Wednesday, the front is expected to have
recently moved through the area, leaving us with gusty north-
northwesterly winds, decreasing cloud cover, and CAA forecast to
drop temperatures into the middle teens to middle 20s overnight,
within a degree or two of potentially breaking a few locations`
daily minimum temperature records for April 5th. Minimum wind chills
will be in the single digits above/below zero. Winds continue breezy
out of the north-northwest during the morning hours on Wednesday,
before tapering off in the afternoon as the low continues to pull
away to the northeast. Afternoon highs Wednesday are expected to be
around 15-20 degrees below normal, in the middle 30s to upper 40s.
Fire weather conditions for Wednesday currently just looking like
borderline elevated for far southern portions of the area, with
maximum wind gusts in the low to middle 20s (mph) during the
overlapping afternoon period of minimum relative humidity in the
middle teens to low 20s. Overnight lows again Wednesday night into
Thursday morning fall into the middle teens to low 20s with wind
chills in the single digits to low teens. Temperatures thereafter
will gradually warm again, with highs reaching the middle 50s to
middle 60s and lows reaching the middle 20s to middle 30s by the
weekend. A few slight chances for precipitation, likely in the form
of rain, also possible late in the week into the weekend.|

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 950 PM MDT Sat Apr 1 2023

KGLD...VFR conditions are expected through the period. From taf
issuance through sunrise expect south winds gusting up to 25kts
early in the period before veering to the west and decreasing to
around 10kts. On Sunday, west winds around 10kts in the morning
become light and variable for a few hours mid day then establish a
northeast to easterly direction at speeds up to 10kts. For Sunday
evening, expect continued east to northeast winds at speeds up to
10kts.

KMCK...VFR conditions are expected through the period. From taf
issuance through sunrise expect a south wind around 12kts early in
the period before decreasing and eventually becoming westerly at
speeds under 10kts. On Sunday, west winds under 10kts in the
morning veer to the northwest at similar speeds by mid morning
then become light and variable through mid afternoon. From late
afternoon through the rest of the taf period look for winds to be
from the northeast and east at speeds up to 10kts.

&&

.FIRE WEATHER...
Issued at 248 PM MDT Sat Apr 1 2023

Saturday...Red Flag Warning remains in effect for Kit Carson/
Cheyenne counties in Colorado, and Wallace/Greeley counties in
Kansas through 700 PM MDT. Counties surrounding the Warning are
coming close to criteria especially for wind, but humidity shouldn`t
hit for the 3-hour period.

Sunday...a Fire Weather Watch has been issued for Kit Carson and
Cheyenne from noon to 700 PM MDT. Humidity is expected to reach
criteria and dry weather persists area-wide. Winds will be close
with best chances in Cheyenne county.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...Fire Weather Watch from Sunday afternoon through Sunday evening
     for COZ253-254.

NE...NONE.
&&

$$

UPDATE...99
SHORT TERM...JN
LONG TERM...CC
AVIATION...99
FIRE WEATHER...JN



Area Forecast Discussion

National Weather Service Gray ME

 1110 PM EDT Sat Apr 1 2023

.SYNOPSIS...
A cold front will cross the region this evening bringing
scattered showers and gusty thunderstorms. Very windy conditions
will continue on Sunday before high pressure crests the East
Coast Sunday night. A clipper crosses with some showers on
Monday, followed by a another slow moving system with more rain
showers Wednesday and Thursday. High pressure will build in late
in the week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
11 PM Update...Fog is really the only concern at the moment as
all showers and storms have moved offshore. The dense fog
advisory will remain in effect until 1 am when cold front should
advance and mix things up.

9 PM Mesoscale Update...At least one storm near Hooksett grew
upscale enough (55 dBz to around 25 kft) to necessitate a severe
thunderstorm warning mainly for hail potential. These storms are
moving over a cold boundary layer, but just above the shallow
boundary layer, sufficient instability and shear is available
for robust updrafts. So, we expect some storms with frequent
lightning and mainly small hail across southern NH and York
County ME before the storms move offshore within 2 hours.

755 PM Mesoscale Update...Line of showers that was tracking
across NY State has encountered richer moisture in the vicinity
of a warm from across southwestern NH. This has resulted in a
significant uptick of lightning in Cheshire County with upscale
cell growth. The main threat with this activity as it moves into
the Monadnocks is Pea to Nickel size hail and gusty winds up to
35 MPH as it becomes elevated. Not sure how far east the
lightning producing nature will last, but to the border with
York County ME is not impossible.

May consider a dense fog advisory for portions of Maine shortly,
although showers will probably disrupt fog formation here in
another couple of hours.

6 PM Update...Convective line to our west across Upstate NY
continues to weaken as SFC dewpoints have been in the 20s and
30s back there. Dewpoints are higher in southwestern NH, but
limited heating instability is meager. At this point we expect
some gusty showers with a few rumbles of thunder to move across
western and southwestern NH with a few gusts up to 40 kt
possible. Otherwise the warm front continues to stay put with
cold/stable air in place at the SFC for much of the rest of the
forecast area.

Previously...

A strong cold front will cross the region beginning by 00Z. The
latest HRRR continues to indicate convection reaching western
New Hampshire during this period and quickly moving to the east.
Wind fields and instability ahead of this line may allow for
strong storms to cross the region with very gusty winds and some
hail. An isolated storm or two may become severe as well with
SPC having southern portions of our forecast area in a marginal
risk.

Temperatures will be quite changeable this evening both ahead of
and with the passage of the front. Have included a nondiurnal
temperature curve for the first few hours of the near term
portion of the forecast.

Gradient winds will also align through an increasingly deep
layer later tonight. Mixing profiles suggest wind gusts will run
up to 40 mph.

A light coating of snow will fall in the mountains tonight after
the precipitation changeover to snow from rain.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Windy conditions will continue on Sunday as the surface low
strengthens and moves out to sea. Strong cold air advection will
support below average temperatures for this time of the year
with highs only inn the 20s and 30s north to around 40 in the
south.

The surface high building into New England will crest over Maine
and New Hampshire Sunday night. With light winds, mainly clear
skies and low dew points, expect radiational cooling to set in.
Overnight lows will fall quickly to the teens north to the 20s
south.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Overview: Low pressure tracks north of the region Monday evening
bringing the chance of rain and snow showers to the area,
tapering Tuesday morning. High pressure will keep temps a bit
cooler Tuesday, before return flow increases moisture into
Wednesday. This comes ahead of another storm system that could
bring more widespread precipitation mid-week.

Details: Monday will see some increasing return flow ahead of
low pressure. Despite marginal mid level lapse rates, moisture
and forcing will be limited, and believe notable showers should
hold off until the evening outside of the mountains. Snow
chances remain within the northwestern mountains, with warmer
sfc temps south to support mostly rain showers.

Weakening low pressure crossing north of the CWA Monday
night should be strong enough to drop a cold front through ME
and NH by Tuesday morning. This will cool temps for the day
under cloud cover as high pressure reinforces with NW winds.

The next chance for widespread precipitation comes mid-week as
large low pressure across the upper Midwest lofts moisture and
forcing through the Great Lakes and into the Northeast.
Uncertainty resides just how far east a possible occluded front
reaches from this parent low. This would affect timing and
QPF, especially if another area of sfc low pressure develops.
This doesn`t appear too likely given recent ensemble guidance,
but these lows also seem to trend in the more short to medium
range. Associated jet dynamics may also be too far west for more
than a few embedded shortwave, but this leaves much of the
eastern CONUS open for terrific moisture advection from the
south. As a result, PWATs potentially climb to around 1 inch
for the area.

While QPF amounts remain close to two tenths, there does appear
to be an extended amount of time with temperatures perhaps
around 50 degrees for southern NH. So, will want to keep an eye
on snowmelt combined with any increase in rainfall amounts via
training or expansion of synoptic precip.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term...Conditions then improve to VFR after midnight
outside the mountains as a strong west to northwesterly gradient
develops.

VFR conditions expected Sunday and Sunday night. Gusty winds
will relax Sunday night.

Long Term...VFR Monday with MVFR becoming more likely in the
evening for northern and western NH. VFR is likely outside of
the mountains Tuesday, with intermittent MVFR ceilings possible
in NH.

&&

.MARINE...
Short Term...Will be issuing gale warnings with this package.
Winds may gust as high as 35 to 40 kts with the strongest winds
along the outer waters. Gales will continue through Sunday.

Long Term...A few gusts to gale force will be possible Monday
evening as a cold front crosses the waters with low pressure to
the north. Winds and seas should subside below SCA conditions
Tuesday afternoon. Intermittent chances of SCA wind gusts will
be possible through Thursday, where a large storm system will
pass inland.

&&

.HYDROLOGY...
Rainfall and warm temps will lead to snowmelt this evening. The
most significant snowpack loss will be in southern and central
NH where the snowpack is ripe/isothermal and ready to melt out
releasing additional runoff. The drawn out nature of the rain
will help moderate mainstem river rises. Smaller rivers and
creeks in SW NH could be vulnerable to rapid rises which could
reach bankfull.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 1 AM EDT Sunday for MEZ018>028.
NH...Dense Fog Advisory until 1 AM EDT Sunday for NHZ006-009-010.
MARINE...Gale Warning from 4 AM to 6 PM EDT Sunday for ANZ150-152-154.
     Gale Warning from 6 AM to 6 PM EDT Sunday for ANZ151-153.

&&

$$

NEAR TERM...Ekster
SHORT TERM...Cannon
LONG TERM...Cornwell



Area Forecast Discussion

National Weather Service Wilmington NC

 937 PM EDT Sat Apr 1 2023

.SYNOPSIS...
Cool high pressure will build in briefly Sunday before we warm
back up early Monday through Wednesday, entering a spring like
pattern. Daily chances for showers and isolated thunderstorms
come into play by Tuesday with another possible cold frontal
passage later in the week.

&&

.UPDATE...
Forecast updated to cancel the High Surf Advisory and convert
the upcoming expiring Gale Warning to a Small Craft Advisory
through Sunday morning. Bumped up temps and dewpoints over the
next several hours but otherwise no big changes from the
previous forecast.

&&

.NEAR TERM /THROUGH SUNDAY/...
Convection along the pre-frontal trough will continue to move
toward the coast this afternoon, while a dry frontal passage is
expected tonight. Could see a flare-up in convection prior to
encountering a more-stable marine environment over the next hour
or two. POPs will continue to trend downward during the
afternoon, with a much drier column in place by this evening per
cross sections. The pressure gradient will keep conditions
breezy, but not at Wind Advisory thresholds except for the
immediate coastal areas for a while longer, especially coastal
Brunswick, New Hanover, and Pender. Plan to lower the advisory
inland areas with the next forecast issuance. Otherwise, H5
zonal flow will prevail on Sunday with surface high pressure
across the area. This pattern will result in seasonable weather.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
Sfc high pressure will be overhead at the start of the period,
quickly moving offshore to the east putting us in light onshore flow
overnight. Clouds will initially start off as high cirrus with mid-
level cloud cover building in towards Monday morning due to a
passing shortwave. Despite virtually calm winds the clouds should
inhibit radiational cooling, with Sunday night lows in the mid-upper
40s, near 50 at the coast.

With the aforementioned shortwave moving through Monday, building
moisture and spotty PVA aloft could result in light shower formation
but not amounting to too much. Best chances for any accumulation
will be along the SC coast. Weak WAA during the day could result in
highs getting to near 70 Monday. These conditions will continue
overnight with lows nearly 10 degrees warmer in the mid-upper
50s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Ridging continues into mid week before a trough looks to move
through late Wednesday and spotty PVA aloft starts to filter in over
the area. We become more entrenched in this warm, moist air mass
ahead of the trough, highs nearing the mid 80s come Wednesday with
likely daily sea breezes and low diurnal POPs possible. A sfc cold
front approaches late Wed into Thu with precip chances increasing
ahead of it. This front seems to slow noticeably, models now showing
it pushing through late Thursday into early Friday but wouldn`t be
surprised if timing changes with newer guidance. Winds shift to out
of the NE with colder high pressure ridging down from the north
headed into the weekend. CAD is possible Fri and Sat, with highs
dropping from the 80s into the 60s.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR and mostly SKC though the 00Z TAF period. Rain chances have
all but ended this evening across the area, but gusty winds up
to ~30 kt continue. With CAA overnight, winds will stay
somewhat elevated but still slowly diminish. Some LLWS possible
as well, but not extremely strong due to the higher sfc winds.
Light and variable winds into Sunday aftn as weak sfc high
pressure moves into the area.

Extended Outlook...Mainly VFR expected through mid week.

&&

.MARINE...
Through Sunday...Strong SWly winds will continue ahead of a
pre- frontal trough and cold front, both approaching the waters
from the west. Will maintain a marginal Gale Warning until the
early evening based on some of marine observations this
afternoon, HRRR projections, and with the strong low-level winds
field expected to persist. Ultimately the Gale Warning will
need to be replaced by a Small Craft Advisory sometime this
evening. Winds will veer, and will diminish in earnest during
Sunday as high pressure builds across the area. Seas will be
highest this evening, then a range of seas will increase once
the offshore fetch develops tonight. Seas will subside more-so
during Sunday given the lighter winds expected. Otherwise,
scattered showers and a few thunderstorms are possible,
especially with the pre- frontal trough later this afternoon.

Sunday Night through Thursday... Sub-SCA conditions look to
persist through the end of the period. SE`ly winds veer more
S`ly Tuesday, generally AOB 10 kt, increasing slightly into
Wednesday becoming 10-15 kt. Seas generally 2-3 ft with a weak
NE swell at 8-9 seconds and a southerly wind wave 2-3 ft at 5-7
seconds.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 9 AM EDT Sunday for AMZ250-252.
     Small Craft Advisory until 6 AM EDT Sunday for AMZ254-256.

&&

$$
SYNOPSIS...ILM
UPDATE...MAS
NEAR TERM...SRP
SHORT TERM...LEW
LONG TERM...LEW
AVIATION...MAS
MARINE...LEW/SRP



Area Forecast Discussion

National Weather Service Mobile AL

 628 PM CDT Sat Apr 1 2023

...New AVIATION...

.AVIATION...
(00Z TAFS)
Issued at 617 PM CDT Sat Apr 1 2023

At 23z, a surface cold front has pushed near I-65, with
northwesterly winds northwest and southwest to west south. A few
residual showers have moved south of the coast and are of no
consequence to area TAF sites. CIGs were at upper end MVFR or
higher, which am anticipating on remaining so through the rest of
the forecast. Winds will shift to northwest to northerly 5 to 10
knots overnight. With the weak nature of the passing cold front,
guidance is advertising northerly winds around 5 knots will shift
to southeast to southerly 5 to 10 knots, around 10 knots along the
coast as surface high pressure near the East Coast re-asserts
itself.
/16

&&

.PREV DISCUSSION... /issued 354 PM CDT Sat Apr 1 2023/

..New NEAR TERM, SHORT TERM, LONG TERM, MARINE...

NEAR TERM...
(Now through Sunday)
Issued at 324 PM CDT Sat Apr 1 2023

A vigorous upper trof over the interior eastern states moves off
into the western Atlantic tonight. A fairly zonal flow prevails
over the forecast area meanwhile and continues into Sunday while a
shortwave trof advances across the south central states. A cold
front currently extending from south central Alabama into
extreme southeast Mississippi will progress slowly into the
northern Gulf this evening. A broken line of convection oriented
near/along the frontal boundary is expected to steadily diminish
this afternoon with dry conditions prevailing by early this
evening. There is a small potential for a strong storm mainly over
the western Florida panhandle during the rest of this afternoon.
Much drier deep layer air settles over the region in the wake of
the front tonight with a generally modest recovery on Sunday as a
light southeasterly flow develops over the area. Dry conditions
tonight continue into Sunday as the modest return of deep layer
moisture looks too limited to consider pops. Lows tonight range
from the upper 40s well inland to the mid/upper 50s near the
coast. Highs on Sunday will be mostly in the mid to upper 70s.
Based on the latest area webcams, have cancelled the marine Dense
Fog Advisory for the Mississippi Sound and southern Mobile Bay,
but have also extended the advisory for the near shore Alabama
waters until 4 pm and included the near shore waters of the
western Florida panhandle. A high risk of rip currents is in
effect until 7 pm, after which a moderate risk follows for tonight
with a low risk for Sunday./ 29

SHORT TERM...
(Sunday night through Tuesday night)
Issued at 324 PM CDT Sat Apr 1 2023

The short term period starts off with an interesting scenario of a
northward advancing warm front across far southeastern MS into
southwestern AL and an approaching shortwave trough across the
region late Sunday night into Monday morning. This will in turn
bring a chance for showers and thunderstorms across the region,
gradually clearing through the day. In the wake of the shortwave,
upper level ridging builds in and we dry out for Monday night into
Tuesday night. Temperatures remain well above normal to near
record territory in the lower to middle 80`s both days, and lows
go from the upper 50`s and lower 60`s Sunday night to upper 60`s
and lower 70`s for both Monday and Tuesday nights.

Now to elaborate on the aforementioned shortwave early Monday
morning. CAMs are beginning to get within range and paint a wide
spread of scenarios in terms of the convective evolution across
the region. Impacts will solely depend on the northward
advancement of the warm front, which will be creeping onshore
sometime near or just after midnight Sunday night. Along and
south of the warm front will feature sufficient moisture along
with warming temperatures to generate around 500 to 750j/kg of
MLCAPE. Forecast hodographs are quite large and curved, with deep
layer shear of around 60kts and rather streamwise sfc-1km and
sfc-3km SRH values in the 300 to 400 range. North of the warm
front, there is evidence of some elevated CAPE with MUCAPE values
around 600j/kg. If this were to improve to closer to 1,000j/kg
with the incoming forcing it would not surprise me if a couple
elevated splitting supercells with small hail potential can
manifest. The problem area could be in the vicinity of and south
of the warm front. At this time, most the guidance suggests the
warm front is too slow to advance northward and we end up with
mostly elevated convection and heavy rain. However, there are
several CAMs that are being devious and advancing the warm front
northward quicker (something that is certainly on the table
considering how things have trended in the 48 hours prior to an
event this year). IF we manage to get surface based convection, a
better threat for tornadoes and damaging winds could materialize
across far southeastern MS into far southwestern AL. This is
captured somewhat by the WRF-ARW and last few runs of the HRRR in
the form of an MCS- like complex advancing southeastward during
the pre- dawn hours. While I can`t rule this scenario out, I`d
like to see more model support for it before sounding any alarms
on a more robust severe potential. As we move closer to the event
time, we will likely get a better idea of where the warm front
will end up and if there is any threat for severe weather.
Regardless, moderate to heavy rainfall will likely occur over
interior areas of southeastern MS and southwestern AL where
forcing is strongest associated with some overrunning
precipitation north of the warm front. MM/25

LONG TERM...
(Wednesday through Saturday)
Issued at 324 PM CDT Sat Apr 1 2023

Once again, no significant changes to the extended forecast. Upper
level ridging across the Gulf of Mexico dominates the forecast,
with perhaps a couple weak shortwaves rounding the periphery of
the ridge mainly later in the week into the weekend. Likewise,
PoPs reflect this with generally slight chance to chance PoPs on
any given day, perhaps with best chances as we get into Thursday, Friday
and Saturday for much of the area. Prior to that, any rain should
be limited to along and northwest of the I-65 corridor Wednesday.
A "cold" front attempts to push into the area sometime Wednesday
into Wednesday night, hanging up along or north of the I-10
corridor. This feature will serve as a focus for any convection to
develop each day. At this time, with relatively meager CAPE
values forecast I don`t foresee any severe threat across the area
through the period. Temperatures will be quite warm Wednesday in
the lower to middle 80`s, but drop off into the middle to upper
70`s west of the I-65 corridor and lower 80`s east of the I-65
corridor for Thursday through Saturday. MM/25

MARINE...
Issued at 324 PM CDT Sat Apr 1 2023

Light to moderate southwesterly winds switch to
northerly tonight as a cold front moves through. Areas of
dense marine fog will will continue to erode into this evening
across the nearshore waters. A light to moderate southeasterly
flow develops on Sunday, with an onshore flow expected through
midweek. MM/25

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk until 7 PM CDT this evening for ALZ265-266.

FL...High Rip Current Risk until 7 PM CDT this evening for FLZ202-204-
     206.

MS...None.
GM...None.
&&

$$

This product is also available on the web at:
www.weather.gov/mob



Area Forecast Discussion

National Weather Service Twin Cities/Chanhassen MN

 736 PM CDT Sat Apr 1 2023

.DISCUSSION...(This evening through Saturday)
Issued at 302 PM CDT Sat Apr 1 2023

KEY MESSAGES:

- Chance of a wintry mix late tonight and early Saturday with minor
  impacts possible.

- Another major winter storm will impact the Upper Midwest Tuesday
  into Wednesday. Significant snowfall, strong winds, heavy rainfall,
  and thunderstorms are possible depending on the eventual track.

Much has improved in the last 12 hours as the system responsible for
producing thunderstorms and heavy snow has pushed well off to the
east. Drier air as arrived with abundant April sunshine, enough to
take a bite out of the fresh snowpack. Still, temperatures remain
much below normal today, and with light winds this evening, should
drop into the teens and 20s. After midnight, strengthening southerly
flow and increasing cloud cover will bring milder air back in by
early Sunday. A short wave will swing east across the northern Plains
and Upper Midwest early Sunday, which could bring a brief period of
light snow or freezing rain to central MN and western WI. There will
be quite a bit of dry air below the 8-10kft cloud deck, however, and
any resultant precipitation that can survive that dry layer won`t
amount to much. PoPs have been increased, especially in WI, but
anything more than minor impacts aren`t anticipated. A cold front
will follow in the afternoon with winds becoming west and gusty.
Should see gusts of 30 to 40 mph with steepening low level lapse
rates and CAA. Temperatures will be warmest over WI and southern MN
where 50 is possible, but they will drop mid to late afternoon behind
the front.

Attention then turns to the next large system to impact much of the
U.S. early next week. Overall, model consistency with this so far has
been quite good. However, with the track being overhead, even small
shifts to the east or west could mean big changes to the forecast.
Generally, the low will track from Colorado to the Upper Mississippi
Valley (likely MN) by Tuesday night. An arc of precipitation will
develop over the central and northern Plains late Monday night and
overspread the area Tuesday. Thermal profiles suggest a wintry mix at
the onset in most locations. As the low tracks into MN, winds will
shift southeasterly to the east of the track and turn any wintry mix
to rain. Steep mid level lapse rates and a prominent, moist inversion
around 750 mb could lead to robust elevated instability by Tuesday
evening. Elevated supercells with large hail will be a threat. The
surface warm front will likely be hung up along the southern edge of
the snowpack over southern MN. Storms south of there would likely be
surface-based and capable of all severe weather hazards. Increased
thunderstorm chances Tuesday afternoon and evening ahead of the
system.

On the cold side, a well-developed trowal and associated deformation
snow band will drop significant snow totals (possibly in excess of a
foot) across the Dakotas and western and northern Minnesota Tuesday
into Wednesday. Winds will also be quite strong as the sub-990mb low
tracks through. CAA will be stronger than with yesterday`s system and
low level lapse rates will be steeper, so confidence in 40+ kt wind
gusts are higher. A large blizzard may develop on the western half of
the system, creating significant impacts.

Ensemble spread is tighter than usual for the track, but
longitudinally still ranges from western Minnesota to western
Wisconsin. While overall confidence is high on a large scale,
locally for our CWA confidence is lower than normal with such a
dichotomy of potential outcomes on either side of the low center.

Wrap around snow and strong winds should impact the whole region
Wednesday with the potential for light accumulations. High pressure
will then slide east across the area late week and southwesterly flow
could finally bring the season`s first 50 for many next weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 709 PM CDT Sat Apr 1 2023

Not many changes from the going TAFs, with the arrival of a LLJ
tonight expected to bring mid-level clouds and LLWS. We`ll see strong
warm air advection and precip generation with this LLJ as well, but
very dry air below 10k feet leads to uncertainty with whether or not
that precipitation reaches the ground. There is concern though that
precip chances are much better than what the CAMs let on as the Euro
ensemble has just 1 of its 51 members that is completely dry for
MSP Sunday morning. At this point, left prob30s for precip in at STC
and MSP and went prevailing for precip in western WI, where the euro
ensemble mean QPF is up over 0.1". Precip will be brief, but from
wet bulbing, it looks to be a mix of rain, freezing rain, and snow.
Behind this batch of clouds, followed the idea of the HRRR and RAP
that skies will clear out Sunday afternoon (we`re not buying into the
IFR cigs the LAV brings in).

KMSP...Was on the fence about converting our prob30 to a tempo or
even prevailing group, but kept it prob30 for now. Type looks like
it could be predominately liquid (so rain or freezing rain depending
on surface temperatures), but only looks to last for up to 1 hour
between 11z and 13z. Also like the idea of the RAP/HRRR that
subsidence and dry air in the wake of the morning wave will lead to
mainly clear skies in the afternoon.

/OUTLOOK FOR KMSP/
Mon...VFR. Wind NW 5-10 kts.
Tue...MVFR-IFR with RASN. Wind ENE 15-25G30-35 kts.
Wed...MVFR-IFR with -SHSN. Wind WSW 20-30G40 kts becoming W.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&

$$

DISCUSSION...Borghoff
AVIATION...MPG