Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/02/21
Area Forecast Discussion
National Weather Service Bismarck ND
958 PM CDT Thu Apr 1 2021
.UPDATE...
Issued at 958 PM CDT Thu Apr 1 2021
The Red Flag Warning has been allowed to expire. Most locations
are now reporting humidity above 20 percent and sustained wind
speeds below 20 mph.
The RAP and HRRR are advertising dewpoints much lower for Friday
afternoon than our current forecast (as much as 10 degrees
Fahrenheit). This would have huge implications on the potential
for critical fire weather conditions. Will allow additional
guidance and upstream trends to be further evaluated before making
any changes to the forecast.
Updates to sky cover were based on the GFS 300 mb RH field, which
seems to have a decent representation of current trends.
UPDATE Issued at 636 PM CDT Thu Apr 1 2021
The main concern early this evening continues to be critical fire
weather conditions. Many locations across western North Dakota
continue to report relative humidity around 10 percent, with winds
in the 10 to 20 mph range. Farther east, relative humidity is
closer to 15 percent, but with winds around 15 to 25 mph. We
expect a slow but steady improvement over the next few hours, with
decreasing wind speeds and increasing humidity. The timing of the
Red Flag Warning remains on track.
Cloud cover was increased this evening based on current trends.
&&
.SHORT TERM...(This afternoon through Friday night)
Issued at 133 PM CDT Thu Apr 1 2021
Critical fire weather conditions continue across all of western
and central North Dakota through this evening.
At the surface, a diffuse warm frontal boundary has generally
washed out as it has crossed the state and the pressure gradient
continues to tighten a bit. This has led to some breezy
conditions with sustained southerly winds up to 25 mph and gusts
to 35 mph. Additionally, widespread observations of relative
humidity values below 20 percent have been noted. These humidity
values should continue to plummet through the afternoon, possibly
down into the upper single digits in some locations. Along with
very dry vegetation, these conditions suggest the Red Flag
Warning for all of western and central North Dakota is in good
shape through the evening hours. Most of the area should see highs
in the 60s today but a few 70s will be possible across the
southwest.
Winds will start to relax after sunset and the critical fire
weather threat will also gradually diminish as we lose daytime
heating and dewpoints come up.
The upper ridge axis will continue to move across the state
overnight as a weak and dry shortwave skirts us to the north of
the International Border, transitioning us into more of a zonal
flow regime on Friday. We will likely see highs a bit warmer than
today Friday afternoon, with plentiful readings in the lower 70s
across the south. The very dry airmass will remain in place
leading to another afternoon where humidity values will dip into
the 13 to 20 percent range for most of western and central North
Dakota. However, winds be lighter than today. Therefore, near
critical fire weather conditions will once again be possible, but
the lack of stronger winds should keep us from needing any
headlines at the moment. The one area to watch will be east of
the Highway 83 corridor where we may see northwest winds
approaching 20 mph for a couple hours in the afternoon. Expect
Friday night lows in the 30s.
.LONG TERM...(Saturday through Thursday)
Issued at 133 PM CDT Thu Apr 1 2021
We transition to low amplitude west northwest flow aloft through
the weekend as the broad upper ridge across the west continues to
nudge into the region. While the NBM has backed off a bit on high
temperatures Saturday through Monday, we coordinated with our
neighboring offices to trend towards the 75th percentile of the
NBM guidance. Given the low amplitude ridging that will be in
place and considering the NBM has been consistently been too cool
recently for highs, this seems like a reasonable solution. This
will mean widespread highs in the 70s and even a few 80s across
the far south Saturday through Monday.
Dry air lingers through the weekend, so any day with an increase
in wind will raise fire weather concerns, likely through Monday or
even Tuesday of next week.
Next best chance for any precipitation will be next week after
Monday, when more of a southwesterly flow pattern tries to
develop. Uncertainty remains high amongst ensemble members, with
the latest WPC cluster analysis trended towards less potential for
much needed moisture, though not entirely dry either.
The deterministic GFS remains the wet outlier showing a strong
low moving through Tuesday through Thursday. However, looking
closer at the ensemble members it is clear that the deterministic
run is one of the more extreme outliers in the GEFS. Thus,
wouldn`t put too much credence into its solution at this time.
Will continue to hold slight chance PoPs in the forecast for this
time period for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 636 PM CDT Thu Apr 1 2021
VFR conditions are expected through the forecast period. Southerly
winds will remain sustained around 10-15 kts through tonight,
turning to the northwest Friday morning and afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 10 PM CDT /9 PM MDT/ this evening for
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...Hollan
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Boston/Norton MA
1049 PM EDT Thu Apr 1 2021
.SYNOPSIS...
Mid-level trough slides east on Friday, cold and mainly dry
heading into Friday. Surface low moves north into the Gulf of
Saint Lawrence while a surface high builds across the southeast.
Seasonably cool and dry weather for the weekend under high
pressure. Though generally dry, conditions turn more unsettled
into early next week as an upper level low over the Maritimes
shifts westward toward coastal New England.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
No major changes to the forecast this evening. Still getting
some reports of sleet and graupel this evening. Not expecting it
to accumulate much. Main tweaks were to temperatures and
precipitation chances to reflect observed trends.
745 PM Update:
Lower-level colder and drier air is beginning to filter
southeastward behind the cold front aloft. Radar mosaic shows a
band of precip along the front`s extent across eastern MA. The
colder air in lower-levels has led to several reports of
graupel or ice pellets from spotters in the Metrowest Boston
area and from the weather observer at Logan Airport. RAP-based
soundings bear this out with sub-0C wet-bulb temps around
950-900 mb in the cold air advection, suggesting some re-
freezing of rain into pellets/graupel below cloud base. This
band of precip will move eastward into the coastal waters in
the next hour or so. While much of it will fall as light
showers, there may continue to be some ice pellets mixing in at
times but will not be impactful.
The colder air leading to steepening lapse rates, along with
2.5-3 mb per 3 hr pressure rises are also contributing to
increasingly blustery conditions in the post- frontal air, with
NW gusts across most of interior MA, CT and RI in the 20 to
near 30 mph range. Did opt to bump up wind gusts through 06z
following the 18z guidance and recent RAP soundings. Thinking
after midnight the gusts should start to lighten up, but
occasional breezes may linger especially into eastern MA, Cape
Cod and into RI given the cold advection all night.
Though skies should begin to gradually clear out later
tonight/overnight, northwest winds/gusts and falling temps will
make it feel rather raw/chilly. Not exactly a great way to
start the first evening of April for those who may prefer milder
weather.
Previous discussion:
The leading edge of our mid-level trough continues to move off the
coast of southern New England leaving a cold and dry air mass aloft.
In fact, temperatures at 850mb are between -10C and -16C, and those
temperatures are 10 to 16 degrees below the seasonal normal. This
will support minimum temperatures Friday morning in the upper teens
to low 20s across the interior and the upper 20s to low 30s across
the coast. Winds remain gusty, at times gusting between 20 and 25
knots, making it feel as if it`s the low teens at the eastern slopes
of the Berkshires and low 20s at the coast. Gusty winds will
diminish by early Friday morning.
As for precipitation, KBOX remains rather quiet heading into the mid
afternoon. A few rain and snow showers do continue upstream, as seen
on KENX, across Albany and points north and west. Those showers
continue to dry out as it reaches the western Berkshire slopes. We
did opt to leave low POPs in the forecast overnight as a few of
these streamers could make it into western MA/CT. Otherwise, PWATS
are crashing through the floor and the mid-levels dry out. But we
are left with enough moisture in the lower levels will continue our
overcast cloud cover through daybreak.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Friday:
The surface low that gave us the unsettled weather today will have
had moved into the Gulf of St. Lawrence. During the day on Friday we
have high pressure building across the entire east coast of the
United States. At the mid-levels over our area the mid-level trough
exits southern New England, but we expect a fair amount of cloud
cover. Additionally, a weak surface trough could provide a few
isolated showers. Confidence in any shower does remain low because
PWATs are less than 1/4 of an inch. If anything a shower would be
brief and more of a nuisance type of shower. As for temperatures, we
are cooler still because of cooler than normal temperatures aloft.
Afternoon temperatures are forecast to reach the low 40s with those
across extreme western MA/CT might only make it to the 40 degrees.
Friday Night:
The mid-level trough moves east of New England and the surface high
expands into southern New England, this will allow for diminishing
clouds and once again cooler temperatures. The low will be dependent
on how much of the cloud cover we erode. As of now we are looking at
temperatures in the 20s across much of the area with the low 30s
across the coastal plain of MA.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Highlights...
* Seasonably cool but mostly sunny and dry for the weekend.
* Greater cloudiness eastern MA/RI with limited chances for light
showers into early next week as closed low in the Maritimes builds
back towards coastal New England. Less clouds and milder temps
western MA/CT.
* Moderating conditions toward midweek.
Details:
Saturday:
High-latitude blocking pattern over the North Atlantic will govern
the large-scale pattern this weekend thru at least the middle part
of next week.
Deep trough initially over the Northeast shifts eastward and evolves
into a closed low later Sat south of Nantucket, a feature which then
passes into the Gulf of Maine into Sat night. Moisture related to
this feature should stay far enough away from coastal MA Sat into
Sunday to allow for mostly clear skies. 925/850 mb thermal trough
also shifts east with moderating but still below-avg temps at these
isobaric levels. By Sunday, 850 mb temps around -3 to -5C should be
common across SNE. Surface high in place will also maintain dry
weather.
Should see highs in the mid-40s to low-50s Sat, with nighttime lows
in the upper 20s to mid 30s. Somewhat milder temps aloft support
highs in the 50s, on the lower side near the coasts and into the mid-
upper 50s across most of the interior due to NW wind downsloping.
Monday into Tuesday:
The high-latitude blocking over the North Atlantic leads to a
continued amount of uncertainty in this portion of the forecast.
This pertains more to how far west will the closed low over the Gulf
of Maine retrograde, which would influence the sky and temperature
forecast across eastern MA/RI. The 12z suite of guidance now however
shows more consistency in westward retrogression of the closed low
into coastal New England by Tuesday. Did increase sky cover a bit
over NBM guidance given this trend toward mostly cloudy for eastern
MA and RI. There may be some very light showers also in this area
but not a washout by any stretch and most should remain generally
dry. Most of western/central MA and much of CT should stay far
enough away from the closed low`s influence to allow for better
conditions. Highs mainly in the 50s for Mon, with highs Tues well
into the 50s to low 60s away from the coast. Under increasing clouds
on Tues, highs near the coast in the mid to upper 50s. Lows
generally similar each night in the upper 30s to low 40s.
Wednesday:
Bit larger variance in GFS/ECMWF guidance compared to early-week on
how quickly will the closed low near coastal New England dig south.
ECMWF is more optimistic with clearing early Wed allowing for
clearing skies and warming temperatures associated with an
amplifying ridge aloft to our west. On the other hand the GFS is
slower and doesn`t really clear the closed low out until late
Wednesday night and would maintain similar conditions to those
around early-week. Will stick with NBM guidance more closely in this
portion of the forecast until there is better agreement.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight: High confidence.
Generally VFR, with MVFR ceilings trending VFR across Cape
Cod/Nantucket. NW gusts 20-25 kt early, and while gust speeds
should start to lower after 03-05z, occasional gusts to 18-20 kt
may continue into the overnight/pre-dawn hrs.
Friday...High confidence.
VFR with NW winds between 5-10 kts.
Friday Night: High confidence.
VFR with easing NW winds.
KBOS TAF...High confidence in TAF. NW gusts may linger after 04z
but with lighter gust speeds.
KBDL TAF...High confidence in TAF.
Outlook /Saturday through Tuesday/...
Saturday: VFR. Breezy.
Saturday Night: VFR.
Sunday through Tuesday: VFR. Breezy.
&&
.MARINE...
Marginal Small Craft Advisories continue for the waters off the
coast of southern New England through Friday afternoon. Northwest
winds do remain gusty between 25 and 30 knots. Gusty winds diminish
early Friday as the surface low moves north into the Gulf of Saint
Lawrence. High pressure builds across the eastern half of the
United States through the end of the weekend. Late Sunday into
early next week a retrograding surface low will move westward
towards the Gulf of Maine.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt. Areas of seas approaching
5 ft.
Saturday Night through Sunday: Winds less than 25 kt. Seas
locally approaching 5 ft.
Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas.
Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Local rough seas. Slight chance of rain showers.
Monday Night: Winds less than 25 kt. Local rough seas.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 AM EDT Friday for ANZ230>234-236-
251.
Small Craft Advisory until noon EDT Friday for ANZ235-237.
Small Craft Advisory until 1 PM EDT Friday for ANZ250.
Small Craft Advisory until 8 PM EDT Friday for ANZ254>256.
&&
$$
SYNOPSIS...Loconto/Gaucher
NEAR TERM...Belk/Loconto/Gaucher
SHORT TERM...Gaucher
LONG TERM...Loconto
AVIATION...Belk/Loconto/Gaucher
MARINE...Belk/Loconto/Gaucher
Area Forecast Discussion
National Weather Service Springfield MO
623 PM CDT Thu Apr 1 2021
.SHORT TERM...(This evening through Friday)
Issued at 1214 PM CDT Thu Apr 1 2021
The key message of the short term forecast is the potential for a
frost and freeze Friday morning. Surface high pressure will be
building south into Missouri overnight. Light winds, clear skies
and a cool airmass will aid radiational cooling and result in low
temperatures in the middle 20s to lower 30s.
The National Blend of Models depicts over an 80% probability of
low temperatures below 32 degrees across the central and eastern
Ozarks. Low temperatures will flirt with record territory at Rolla
and West Plains. Surface winds in southeast Kansas and the Osage
Plain will turn to the southeast overnight and will keep
temperatures warmer compared to the Ozarks. Will continue with
current frost and freeze headlines.
Southerly surface winds will increase Friday in response to a
tightening pressure gradient ahead of a lee-side trough in the
High Plains. High temperatures will rebound to the mid 50s and
60s with dry weather.
.LONG TERM...(Friday Night through Thursday)
Issued at 1214 PM CDT Thu Apr 1 2021
The highlights of the extended forecast is a dry and warmer trend
through Easter weekend into early next week. Chances for showers
and thunderstorms return the middle of next week.
Ensemble members are in solid agreement of an upper ridge
building across the Plains. At the surface, south and southwest
return flow will advect a warmer airmass. Look for high
temperatures to jump above average to the 70s Sunday through the
middle of next week.
The next chance for precipitation will be focused on a shortwave
trough tracking through the Pacific Northwest into the Central
Rockies and ejecting into the Central Plains the middle of next
week. Moisture advection is likely to be sufficient ahead of the
approaching trough to support widespread rainfall. Lift and
instability also support the inclusion of thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 617 PM CDT Thu Apr 1 2021
Mainly VFR conditions with light winds expected this TAF period.
However, the HRRR model is bringing smoke from prescribed forest
burns into the KSGF area after midnight tonight. Right now, that
does not appear to cause significant visibility reductions, but
time will tell.
&&
.CLIMATE...
Issued at 258 AM CDT Wed Mar 31 2021
A cold airmass will impact the Ozarks Thursday night. While the
average last freeze for most of southwest Missouri is around April
15th, the warm weather over the past two weeks has jump started
the growing season. Trees and plants have begun setting buds and
leafing our and will be susceptible to freezing temperatures.
Some areas may approach record lows for tonight into the morning
of the 2nd. Below are the record lows for some locations across
the Ozarks.
Springfield Joplin West Plains Vichy
Low Low Low Low
Fri 20(1936) 25(1992) 22(1992) 24(1992)
2nd
Forecast:
29 34 25 26
Multiple hours of temperatures in the middle 20s are forecast and
will cause damage to sensitive plants and early growth.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Freeze Warning from 1 AM to 9 AM CDT Friday for MOZ055>058-
068>071-079>083-090>092-095>098-104>106.
Frost Advisory from 1 AM to 9 AM CDT Friday for MOZ066-067-077-
078-088-089-093-094-101>103.
KS...Frost Advisory from 1 AM to 9 AM CDT Friday for KSZ073-097-101.
&&
$$
SHORT TERM...Angle
LONG TERM...Angle
AVIATION...Titus
CLIMATE...Angle