Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/30/20
Area Forecast Discussion
National Weather Service Bismarck ND
946 PM CDT Fri May 29 2020
.UPDATE...
Issued at 940 PM CDT Fri May 29 2020
No changes needed from previous update. Recent runs of the RAP
place the descending surface high center track just east of
Rolette county, more focused on the Devils Lake basin to Red
River Valley area. Utilizing the low end of guidance for
temperatures tonight still put lows in Rolette county (and
Bottineau/Pierce to an extent) at around 37-40 F. Additionally,
potential frost conditions don`t look to last more than an hour or
two so we refrained from issuing a Frost Advisory with this
update.
UPDATE Issued at 634 PM CDT Fri May 29 2020
Quiet but chilly conditions expected tonight with lows dipping
into the upper 30s in areas of the far north-central/northeast.
Light reflectivities were observed over McKenzie/Dunn counties and
over the far southwest over Bowman county. With ceilings at 15k
feet or higher and a lack of upstream precipitation reports there
is little confidence in precipitation reaching the surface.
In the north north central, cloud cover is on the decrease as a
surface high continues to build from the north. Low temperatures
will be the challenge with the center of the high likely to pass
through near or just east of Rolette county. Currently forecast
lows in the upper 30s in Rolette county look valid but if the air
mass trajectory trends change tonight, even lower temperatures
will be possible.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 239 PM CDT Fri May 29 2020
Quiet weather and seasonably cool temperatures are expected for the
short term period.
18Z surface analysis shows high pressure centered over the Canadian
Prairie Provinces, with a ridge axis extending south-southeastward
into the central Dakotas. Flow aloft is northwesterly and generally
unperturbed over the Northern Plains, with an upstream ridge axis
over the Northern Rockies and upper level jet streak extending from
western Saskatchewan into the northern Red River Valley. The surface
high/ridge axis will slide eastward tonight, resulting in increasing
southeasterly low level flow across western and central North
Dakota. A weak mid level impulse moving from southeast Montana into
western South Dakota may combine with upslope flow to produce some
scattered showers tonight. Think this activity will stay to the
south and west of North Dakota. Expect a quiet night with cool
temperatures. It should be slightly warmer than last night for most
areas given the increasing surface flow.
The benign weather pattern will continue on Saturday, with very
little progression of synoptic scale features. Expect another quiet
day with a slight uptick in winds across the western half of the
state. Highs will range from the mid 60s to mid 70s.
.LONG TERM...(Saturday night through Friday)
Issued at 239 PM CDT Fri May 29 2020
The long term period is highlighted by temperatures warming to above
normal and periodic chances for thunderstorms through next week.
Models are in agreement that synoptic scale ridging will shift from
the Rockies into the central CONUS by the end of the weekend and
generally hold there through the upcoming week, with varying degrees
of amplitude. This pattern suggests above normal temperatures, which
is supported by a prolonged period of NAEFS 850 mb temperatures
above the climatological 90th percentile and GEFS mean 850 mb
temperatures greater than 15 C. Model consensus calls for highs in
the 80s starting Monday.
Backtracking to Sunday, the surface high will move east into the
Great Lakes region, resulting in a tightening pressure gradient as
the upper level ridge begins to shift over the Northern Plains. This
will create breezy conditions across the area. Model consensus
currently calls for south-southeast winds sustained around 20-25 mph
with gusts near 35 mph. Guidance has been routinely under-
performing with wind speeds in these types of setups over the past
few weeks, so decided to use the strongest wind guidance
available for Sunday, which generally increased winds around 5 mph
above consensus.
A mid level shortwave is forecast to eject off the Northern Rockies
on Sunday, with a lee surface trough sharpening over eastern Montana.
This combined forcing should lead to convective initiation in the
eastern half of Montana Sunday afternoon, where CIN is forecast to
be weaker. SBCAPE exceeding 2000 J/kg is sufficient for severe
weather, but 0-6 km bulk shear around 30-40 kts is only marginal for
rotating updrafts.
Severe storms may move into western North Dakota Sunday evening, but
this threat will be highly dependent on 1) the longitudinal
placement of initial convection, of which there is currently notable
spread among guidance, and 2) storm evolution. Storm evolution
itself may be contingent on the initial storm mode, which is
currently difficult to diagnose. Shear vector orientation relative
to the surface trough switches from parallel directly upstream of
the trough to perpendicular directly downstream. If upscale growth
of convection occurs and storms can become elevated, enough
ingredients may be in place to support a large hail threat with
elevated convection moving into western North Dakota Sunday evening
and into the overnight. But this scenario is still also contingent
on the longitudinal placement of forcing mechanisms, which remains
uncertain at this time.
The mid level shortwave and surface trough are forecast to progress
eastward on Monday. It is possible that remnant showers and sub-
severe thunderstorms persist along these features as they move
across the state late Sunday night into Monday morning. Convection
may be reinvigorated across eastern North Dakota Monday afternoon,
but there are too many uncertainties to message this threat at this
time.
Models tend to favor periodic shortwaves moving across the top of
the broad upper level ridge through the upcoming weak. Any one of
these waves may be capable of sparking thunderstorms, but there are
significant timing differences, even as early as Tuesday. There are
also concerns about the strength of forcing that will be needed to
overcome low to mid level capping inversions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 634 PM CDT Fri May 29 2020
VFR conditions expected at all terminals through the forecast
period. Calm to light winds expected overnight and then becoming
southeast at 10-15 kts across western ND by Saturday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AE
SHORT TERM...Hollan
LONG TERM...Hollan
AVIATION...AE
Area Forecast Discussion
National Weather Service Billings MT
931 PM MDT Fri May 29 2020
.UPDATE...
Convection continues to track through the Beartooth/Absaroka
mountains with the most intense activity staying over Wyoming.
Latest HRRR shows still a chance of some convection developing
over the plains where satellite imagery showed some mid level
moisture and instability was available but temperatures aloft are
warm enough to keep these thunderstorms from becoming too intense.
Minor updates for pops sent. borsum
&&
.Tonight through Saturday night...
A few showers were moving E through the western part of the
forecast area early this afternoon. Weak vorticity was moving into
the area which was inducing surface troughing over the W. ML
Capes were weak, but there was some shear over the area. Steep
lapse rates were confined to the extreme western and southern
fringes of the forecast area. Had chance PoPs this evening over
areas W and S/SE of KBIL, with isolated PoPs over central areas.
RAP showed decent elevated CAPE over KLVM, but convection will
have to overcome a fair amount of CIN to realize it. RAP also
showed decent Bulk Effective Shear for KLVM. So, cannot rule out a
strong storm in the W this evening. Soundings for KBIL and KSHR
did not have any strong convective parameters. Thunderstorms may
contain heavy rainfall with PWAT`s around .8 inches due to moist E
flow.
On Saturday, a strong impulse was forecast to move N to the S OR/N
CA border by 00Z Sunday. This wave continues pushing N Sat. night.
Meanwhile the upper ridge will remain over the forecast area. A
surface boundary sets up along the foothills in the afternoon, and
moves slowly NE overnight. Reef showed high ML Capes along the
foothills which could be influenced by dewpoint pooling. There was
also decent shear. The model did not produce much convection
which suggests there will be CIN to overcome. HREF did not show
much in the way of updraft helicity tracks. Kept PoPs near
mountains/foothills in the afternoon and evening. SPC painted
these areas with a "Marginal" outlook which means there could be
an isolated severe storm. Temps will be mainly in the 80s. Low-
level jet will make for breezy conditions E of KBIL Sat.
afternoon. Arthur
Sunday through Friday...
For Sunday, the upper ridge axis slides east as a disturbance
moves into the Pacific northwest, dragging an associated front
across the area. This will bring a chance for showers or
thunderstorms to the eastern counties Sunday afternoon and
evening. Some of the thunderstorms could be strong to severe with
ample moisture at the surface and modest instability and shear in
place ahead of the front. Before the frontal passage, Sunday looks
to be the warmest day of the year thus far, with high
temperatures approaching records for some locations (lower 90s F).
Uncertainty exists for Tuesday through the remainder of the next
week as an upper low cuts off west of California and troughing
begins to move into the Pacific northwest. The area looks to be
under a southwest flow aloft with multiple disturbances moving
across the forecast area. Unsettled weather is possible resulting
in showers and thunderstorms through the week.
Afternoon highs Sunday will warm into the 80s with some locations
seeing lower 90s. Behind the front Sunday, highs look to range
from the upper 70s to 80s Monday through Friday. With the
increasing temperatures comes increasing snowmelt across the
higher elevations. Rivers and streams will rise in response to the
snowmelt this weekend through early next week. Hooley
&&
.AVIATION...
VFR conditions will prevail tonight through Saturday. Localized
MVFR or lower conditions are possible in thunderstorms across much
of the region, especially south of a line from Roundup to
Ekalaka. Best potential for storms still appears to be over
mountains and foothills. Small hail and gusty winds are possible
with stronger storms. Showers across lower elevations should
clear by Saturday morning. Areas of mountain obscuration will
decrease overnight.
Additional storms development is expected Saturday
afternoon/evening over mountains and foothills, including the KLVM
and KSHR areas. Likewise, expect mountain obscurations to return
Saturday afternoon. Gilstad
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 055/085 060/091 057/086 059/083 056/084 058/082 057/084
21/U 10/B 00/U 11/B 23/T 33/T 33/T
LVM 052/082 058/084 051/084 053/079 052/080 052/078 052/079
22/T 20/N 01/U 13/T 35/T 45/T 45/T
HDN 054/086 060/094 056/088 057/084 055/086 057/085 056/087
21/U 11/B 00/U 11/B 24/T 44/T 33/T
MLS 052/078 058/092 058/085 059/083 057/085 059/085 059/086
00/U 02/T 10/U 11/B 23/T 43/T 32/T
4BQ 050/077 057/092 057/086 056/085 055/084 057/084 057/086
20/N 02/T 10/U 11/B 23/T 34/T 23/T
BHK 048/071 052/084 056/083 056/083 053/082 056/081 057/084
10/N 02/T 20/U 11/B 33/T 43/T 22/T
SHR 052/085 059/091 055/089 056/083 054/083 055/082 055/085
32/T 31/B 00/U 01/B 24/T 43/T 33/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1125 PM EDT Fri May 29 2020
.SYNOPSIS...
A cold front will move through tonight and end the showers and
thunderstorms. A noticeably cooler and drier/less humid airmass
will move into the area over the weekend with temperatures
trending below normal into early next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Still dealing with a lingering severe weather threat across the
southeast portion of the forecast area late this evening, where
01Z SPC mesoanalysis shows mlcapes near 1500j/kg in combination
with 40kts of deep layer shear and 20kts+ of 0-1km shear.
Latest radar loop indicates the cold pool has outrun convection
entering the Lower Susq Valley. However, given the environment,
can`t rule out severe weather from the Harrisburg area south and
east until around 04Z, when HRRR tracks line of convection out of
the forecast area.
Elsewhere, will maintain the chance of showers until passage of
the cold front, which is just entering northwest Pa at 01Z and
should take until around 09Z to clear the southeast counties.
In the wake of the front, winds will turn to the W/NW with
clearing occurring east of the Alleghenies. Lingering low level
moisture ascending the Alleghenies will likely cause stratus to
linger over the western counties.
Low temperatures should range from around 50F over the northwest
mountains, to the mid 60s over the southeast counties.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Early stratus over the Alleghenies should mix out shortly after
sunrise. However, expect increasing clouds to spread in by
midday ahead of an approaching cold front. Although moisture
ahead of this front will be limited, there appears to be decent
large scale forcing ahead of parent shortwave over the Grt Lks.
Have therefore included low POPs for an afternoon shower across
the northern mountains and Laurels.
For the southeast half of the forecast area, model rh profiles
support abundant sunshine in the morning, then increasing afternoon
cumulus ahead of cold front, but little chance of showers.
Maxes will be close to 80 in the SE, but hold in the upper 60s
for the Alleghenies.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Early next week, models are in good agreement on an extended
period of NW flow as a large scale upper trough sharpens over SE
Canada and the Eastern US. An expansive sfc high pressure
builds back in across the Ohio Valley and drifts just south of
PA by Tue and then offshore by the middle of the week. Expect
mainly dry weather and cooler less humid conditions Mon-Tue
(including a couple of chilly mornings, though some cirrus
overhead may keep mins from bottoming out in the 30s over the
northern mountains).
Quick hitting shortwave trough slides through on Tue and may
produce some scattered light showers. The longwave trough
flattens a bit briefly before sharpening again as large ridge
builds over central parts of the country. This will allow
another weak shortwave or two to ripple by overhead on Thu which
will interact with a leftover weak surface boundary (from Wed)
to keep mention of showers in the forecast.
The first half of next weekend is looking pleasant and dry.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
As of 1120 PM, most of the area is free of showers and storms
now.
While there could be a brief shower across the central areas,
took them out of the fcst. Storms possible across the far
southeast until shortly after Midnight.
Back off on lower clouds a little, except the far west.
Earlier discussion below.
00Z TAFS sent.
Still a large area of showers and isolated storms over the
area as of 8 PM, as stronger winds aloft work into the area.
Drop in dewpoints since yesterday has so far kept storms from
being as strong as they are sometimes in late May.
Expect lower CIGS to work into the area later tonight. Main
change to the package was to bring up CIGS to VFR faster on
Saturday morning.
For the rest of this weekend, it remains dry, but we have a
chance of fog in the nrn valleys each morning through Monday.
The next chance for showers will arrive next Tuesday with a
system approaching from the Great Lakes.
Outlook...
Sun-Mon...AM Fog poss. Otherwise VFR.
Tues...chc SHRA/MVFR, mainly NW.
Wed...Sct/nmrs SHRA, TS poss, mainly N.
&&
.CLIMATE...
A record daily rainfall of 1.43 inches was set at Williamsport
yesterday. This breaks the old record of 1.22 inches set back in
1968.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo/Steinbugl
NEAR TERM...Fitzgerald
SHORT TERM...Dangelo/Fitzgerald
LONG TERM...Lambert/Banghoff
AVIATION...Martin
CLIMATE...Evanego/Steinbugl
Area Forecast Discussion
National Weather Service Cheyenne WY
838 PM MDT Fri May 29 2020
.UPDATE...
Issued at 823 PM MDT Fri May 29 2020
Increased the pops and associated QPF in the forecast package for
this evening. Increased coverage of showers and thunderstorm
activity warranted the slight changes. Still expect the shortwave
to move over the region overnight causing another possible round
of showers/thunder in our northern zones overnight. With the
associated cloud cover overnight expected, minimum overnight temps
should stay in the low to mid 50s in the lower terrain.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 235 PM MDT Fri May 29 2020
Cu field has been developing over the past 2 hours over the South
Laramie Range and Laramie Valley. So far, initial attempts at
deeper convection have been unsuccessful, but trends in Day Cloud
Phase Distinction RGB suggest a couple of thunderstorms are
possible in the next few hours. HRRR and NAMNest show cells
developing over Albany and Laramie Counties in Wyoming, but are
shortlived with at most 1000 J/kg of MLCAPE available. Gusty winds
and small hail remain possible with storms that do develop later
this afternoon. Stronger shortwave energy riding the ridge will
pass through northern sections of the CWA later tonight with
showers and thunderstorms possible over Niobrara County in Wyoming
along with Sioux and Dawes County heading into early Saturday
morning. Recent short-term guidance has hinted at stronger storms
diving south into the CWA under 45 kts of effective shear
originating from the Big Horns. So far nothing has initiated in
that area, but the Cu field is building so evening shift will
need to monitor satellite/radar trends. Heavier precipitation
accumulation is expected with the stronger lift as models are
indicating 0.5" of rainfall is very possible, if not slightly
more in stronger cells.
Scattered thunderstorms will be possible this weekend as
shortwave energy passes through under southwest flow with the
passing of the ridge axis to the east. Easterly upslope flow will
back higher moisture up against the Laramie Range Saturday. Axis
of highest instability is expected to setup along the higher
terrain with MLCAPE approaching 2000 J/kg in spots with 35 kts of
effective shear. The Wyoming High Plains will be fighting a cap
so biggest question is whether or not convection can sustain
itself off of the high terrain. Farther west towards Laramie with
the drier boundary layer, impressive inverted-v soundings are
forecast with LCL heights near the freezing level and weak
boundary level winds supporting dry microburst potential. Similar
setup expected Sunday with a dryline along the Laramie Range, but
less capping is expected over the High Plains and steeper mid-
level lapse rates are in place. SPC has highlighted areas along
and east of the Laramie Range with a Marginal Risk for severe
thunderstorms for Saturday and Sunday.
.LONG TERM...(Sunday night through Friday)
Issued at 235 PM MDT Fri May 29 2020
Generally, the ridge axis remains in place east of the CWA heading
into next week with passing shortwaves over the Northern Plains.
Warm weather is expected to continue with daytime temperatures in
the 80s expected across much of Southeast Wyoming and in the 90s for
the Nebraska Panhandle. Monday looks to be the warmest day with
Chadron, Sidney, and Scottsbluff approaching record highs in the
mid-to-upper 90s. A 500 mb cutoff low sitting off the California
Coast will provide additional shortwave energy spinning off of it
moving downflow. This will aid in thunderstorm development across
the area Monday through Wednesday. By Thursday, the low begins to
propagate through the region and eventually breaking down the
ridging pattern over the Front Range and Great Plains.
&&
.AVIATION...(For the 00Z TAFS through Saturday afternoon)
Issued at 550 PM MDT Fri May 29 2020
Isolated showers and thunderstorms are expected across far eastern
Wyoming and western Nebraska through late this evening, especially
KCDR and KAIA. Lower CIGS and MVFR conditions are possible with
this thunderstorm activity, but confidence is pretty low at this
time. Low stratus expected to form late tonight near KCDR and KAIA
terminals after 09Z.
HAZARDS/WEATHER TRENDS: Generally VFR, especially for the southeast
Wyoming terminals. Brief periods of MVFR for KAIA and KCDR due to
thunderstorms and the potential for low clouds late tonight. These
conditions are less likely near KBFF and KSNY.
&&
.FIRE WEATHER...
Issued at 235 PM MDT Fri May 29 2020
Isolated to scattered thunderstorms are possible the next few
days with gusty outflow winds possible. Warming trend continues
through the weekend and into next week. Areas of Carbon County in
Wyoming will see drops in RH values to near critical levels with
gusty winds around 25 MPH Sunday afternoon. Portions of the
Nebraska Panhandle will warm into the 90s with afternoon RH values
dropping into the teens Monday. Will be something to watch if
fuels are deemed ready.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...BW
SHORT TERM...MB
LONG TERM...MB
AVIATION...TJT
FIRE WEATHER...MB
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1032 PM EDT Fri May 29 2020
.SYNOPSIS...
A cold front will continue to slowly approach the area from the
west tonight and Saturday moving offshore Saturday night. High
pressure will build into the region late this weekend and early
next week.ild into the region late this weekend and early next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 1025 PM Friday...Latest surface analysis continues to
show a deep flow of moisture with waning showers and
thunderstorms across much of the southeastern CONUS tonight.
Convective activity expected to continue offshore for much of
the night (as is common) with a relative lull inland. Grids in
good shape this hour with no changes needed.
Prev disc...Deep moisture remains in place across eastern NC
fueling bands of thunderstorms with heavy downpours at late
afternoon. Flood Advisories were issued earlier for northwest
Duplin County and are currently in effect in the Jacksonville
area. This area coincides with the best Theta-E and precipitable
water axis. Should see activity slowly work toward the coast
over the next few hours, then a lull can be expected one again
later this evening into tonight. The latest HRRR and 3km NAM
show showers and storms redeveloping near or just offshore
toward morning, much like this morning, and blossoming along the
coast by daybreak Saturday. PoPs continue in the high chance to
likely category this evening, dropping back to chance overnight
as loss of heating leads to at least some dissipation of the
convection. Another warm and muggy night expected with lows
69-73 degrees.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
As of 315 PM Friday...Another surge of deep moisture ahead of a
slow-moving cold front will lead to widespread showers and
scattered thunderstorms Saturday. Precipitable waters in excess
of 2 inches will again make heavy downpours the primary threat
tomorrow. Most of the area is also in a Marginal Threat of
severe weather. Although low-level shear is limited, there
could be a brief wet microburst or two during the day. What
breaks that occur in the clouds will lead to a very warm
afternoon as thickness values support highs in the low to mid
80s area-wide.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
As of 245 AM Friday...A cold front will approach the area
Saturday evening, then push offshore early Sunday with high
pressure building into the region early next week providing
drier and cooler weather. High pressure moved offshore by the
middle of the week with a series of disturbances bringing rain
chances back into the forecast.
Saturday night...The upper level trough and cold front approach
the area Saturday evening. Temps will remain quite mild, with
lows only in the mid to upper 60s.
Sunday through Tuesday...The front is progged to be offshore by
Sunday morning with high pressure building in from the
northwest through the day. The high will be centered across the
area Monday and Tuesday with NW downslope flow aloft bringing
dry and much more comfortable conditions with dewpoints dropping
into the 40s and 50s and temps about 5-10 degrees below normal
with highs in the 70s and lows in the 50s.
Tuesday night through Thursday...High pressure will slide
offshore Tuesday night with a series of weak disturbances
moving through the NW flow aloft bring a chance of showers
across the area through the middle of the week. SW return flow
around the high offshore will bring much warmer temps with highs
well into the 80s, and could approach 90 on Thursday.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term /through 18Z Saturday/...
As of 800 PM Fri...Variable flight conditions across the region
today with predominantly VFR conditions with pockets of sub-VFR
in heavier rainfall/shower activity. Biggest question tonight is
whether fog or stratus will overspread the region pre-dawn.
Satellite trends suggest mainly broken to overcast conditions
will prevail especially thanks to downstream convection
streaming across the region, but if some regions sufficiently
clear low-level moisture profiles combined with light winds
certainly could promote fog. Uncertainty here is too high to
mention explicitly in TAFs but did show MVFR ceilings.
More seabreeze shower/thunderstorm activity is expected tomorrow
afternoon with MVFR conditions in the morning giving way to
variable flight conditions by the afternoon with predominant VFR
except in showers/storms.
Long Term /Saturday Night through Wednesday/...
As of 330 PM Friday...An unsettled pattern will continue
Saturday night bringing periods of sub-VFR condition to the
terminals. With S/SW flow aloft, expect predominantly MVFR
conditions with occasional IFR/LIFR in heavier downpours. A cold
front will push across rtes early Sunday with high pressure and
a much drier airmass building into the area bringing pred VFR
conditions Sunday through Tuesday.
&&
.MARINE...
Short Term /Tonight and Saturday/...
As of 1030 PM Fri...Small Craft seas have failed to materialize
per observations and winds are not expected to increase beyond
current levels. Dropped the headline although couple 6 foot
waves are not out of the question overnight.
Prev disc...At late afternoon, winds are S/SSW at 10-20 knots
with seas 3-5 feet, with some 6-footers over the outer central
waters. No big change in the overall forecast thinking. A cold
front will continue to slowly approach from the west tonight, as
S/SW winds 10-20 kt will continue tonight. Winds Saturday
should primary be 10-15 knots from the SW with seas 3-5 feet as
Small Craft Advisories expire during late morning.
Long Term /Saturday Night through Wednesday/...
As of 330 PM Friday...A cold front will slowly approach from
the NW Saturday night before moving offshore Sunday morning. Winds
become N/NE around 10-20 kt with gust to around 25 kt at times
with seas around 3-6 ft Sunday into Monday. High pressure will
become centered across the area Tuesday bringing light and
variable winds and seas around 2 to 3 ft.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MHX
NEAR TERM...CTC/MS
SHORT TERM...CTC
LONG TERM...SK
AVIATION...SK/MS
MARINE...CTC/SK/MS
Area Forecast Discussion
National Weather Service Marquette MI
808 PM EDT Fri May 29 2020
.SHORT TERM...(This evening through Saturday)
Issued at 143 PM EDT FRI MAY 29 2020
A weak thermal trough of colder air aloft behind a cold front this
morning is bringing some diurnally-forced -SHRA across the west and
central this afternoon. A sharper shortwave is providing some
additional lift, which is helping some of these showers overcome
some increasingly dryer low-levels. Latest RAP analysis suggests
850mb temps have fallen to around 4C this afternoon across the west
as models suggest these will slowly fall through the evening as weak
CAA continues. Expect these isolated to scattered rain showers to
continue into the early evening...mainly across the west and central.
Tonight, as CAA continues, models suggest 850mb temps to fall to
near -2C by tomorrow morning. With this, have increased cloud cover
from the going forecast a little bit...which also led to slightly
warmer temperatures for the lows tonight. The shortwave axis should
be east of the UP tonight and without this additional forcing,
expecting any -SHRA chances to come to an end before sunset. By
tomorrow morning, another shortwave will move across the western
half of the UP, which will bring another quick chance at -SHRA. Look
for lows to be generally in the 30s, to near 40 across the south
half.
Tomorrow, some -SHRA will linger across central portions of Upper
Michigan in the morning. These showers will quickly come to an end
by the afternoon as heights begin to rise behind the passing wave.
Models suggest 850mb temps begin to raise in the afternoon as winds
slowly back a bit more from the WNW. As the heights rise and CAA
comes to an end by the afternoon, expecting skies to begin to scatter
out, which should bring some afternoon sunshine for most. Model
soundings indicated some mixing beginning around 18Z, so have
lowered Tds slightly from the going forecast...which brings RH
values to near 30% across the west half later in the afternoon. High
temperatures will be dependent on how quickly the clouds clear out,
but have went with the middle of the road, which may be too cool
across the west half as well. Expect widespread 50s, with some 60s
possible in the downsloping areas across the south-central and
perhaps across the west in the Baraga Plains.
.LONG TERM...(Saturday night through Friday)
Issued at 317 PM EDT FRI MAY 29 2020
Upper air pattern will have a trough on the west coast, a ridge over
the Rockies into the southern plains and a deep trough over the east
half of the U.S. 00z Sun. The ridge moves out into the plains this
forecast period into 00z Tue. Did not make too many changes to the
going forecast overall. Held off on a frost advisory, freeze watch
at this time for Sat night as confidence in low temperatures is not
high enough yet to issue. Went colder than some guidance, but not as
cold as the lowest guidance found which was the adjmet and adjmav
which would have a hard freeze in the west interior. Went a couple
degrees colder and lowest spot I have for a low Sat night is Amasa
at 31.
In the extended, the GFS and ECMWF show a 500 mb ridge across the
plains with a trough off the west coast and another off the east
coast 12z Tue. A shortwave moves over the top of the ridge and moves
into the upper Great Lakes 12z Wed which pushes a sfc front through
the area. This shortwave helps to dig a trough into New England 12z
Thu with the ridge starting to build back into the plains as the
upper flow amplifies on Fri. Temperatures will remain above normal
for this forecast period. Pushed back timing of pops on Mon with
warm front well off to the west and NBM appeared too quick and has
been for several runs now in bringing pops in too fast. Slowed them
down. Also added a lake breeze look to the pops in the extended with
dry pops over Lake Superior and the shoreline with pops inland
during the day which is typical in the summer with clearing over
Lake Superior and the shoreline with the lake breeze having build-
up cumulus along it inland.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 741 PM EDT FRI MAY 29 2020
Stratocu clouds and diurnally-driven isolated showers this
evening will give way to an upper-level disturbance and a
reinforcing shot of cold air which will briefly enhance lake
clouds and lake showers late tonight into Saturday
morning...mainly at KCMX and KSAW. MVFR conditions at KSAW should
improve to VFR this evening as diurnal instability clouds
dissipate, but then expect MVFR conditions and a few lake-enhanced
showers to move back in later tonight at both KCMX and KSAW later
tonight as the disturbance and shot of colder air moves through
the region. Ridging and drier air behind this disturbance will
result in clearing skies by late morning/early afternoon at KCMX
and KSAW. Expect VFR conditions at KIWD through the period as that
site will stay closer to the surface ridge and associated drier
air. &&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 143 PM EDT FRI MAY 29 2020
Northwest winds will back more to the west briefly this evening,
before a brief shot of colder air brings increasing winds from the
NW tonight. This colder air may bring winds gusting up to around 25
knots tonight, before winds back more from the west and then
southwest on Saturday. High pressure will then linger over the lake
for Sunday. A warm front on Monday evening may bring gusts up to 25
knots from the south, otherwise winds are expected to remain blo 25
knots through the rest of the forecast period.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...07
AVIATION...Voss
MARINE...JAW
Area Forecast Discussion
National Weather Service Paducah KY
614 PM CDT Fri May 29 2020
.UPDATE...
Issued at 613 PM CDT Fri May 29 2020
Updated aviation discussion for the 00 UTC TAF issuance.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 322 PM CDT Fri May 29 2020
At the time of this discussion, the cold front was moving past the
Wabash and Ohio Rivers into parts of southwest Indiana and the
Pennyrile region of west Kentucky. Nearly all of the convection
(showers) were being lifted along and ahead of the frontal
boundary and should exit the region before 5 pm or 6 pm CDT.
The short range, high resolution HRRR and RAP CAM (Convection
Allowing Models) appear to have the best representation in both
time and space with respect to this afternoon`s convection
(including instability) and were incorporated into the forecast
package.
From a longer term perspective, a blend of the NBM (National Blend
of Models) and the Canadian guidance provided a reasonable
assessment of temperatures, dewpoints, cloud cover (or the lack
thereof) for this weekend. Temperatures will be near five degrees
below normal during the weekend, before returning to near normal
in the longer term.
.LONG TERM...(Monday through Friday)
Issued at 322 PM CDT Fri May 29 2020
By Monday, the upper-level trough that kept the weekend cool will
depart to the northeast. Taking its place will be a large upper-
level ridge which will be the predominant feature through the week
for the Midwestern and Plains states. Surface high pressure in the
southeast will shift flow southerly to southwesterly across the Quad
State, bringing tropical air into the region. The storm track is
likely to stay to the north, outside of the forecast area, due to
the ridge. High temperatures will climb from near 80 on Monday to
the upper 80s on Tuesday. Dew points will similarly increase from
the low to mid 50s on Monday to the lower 60s on Tuesday.
Midweek, the ridge will start to spread out from the Rockies to the
East Coast. Reductions in the northern extent of the ridge is likely
to bring the storm track far enough south to affect the Quad State.
Upper-level shortwaves have the potential to bring showers and a few
thunderstorms to the area Thursday and Friday. The ECMWF and GFS
generally agree on the minor break in the ridge that allows
precipitation to reach the area, though these systems being rather
small will keep precip chances on the lower side for now. Following
the upper-level shortwave disturbance, the ridge is likely to
reassert itself over the Midwest, keeping highs near 90 and lows
near 70 mid to late week. Heat index values are likely to reach the
lower 90s Wednesday and Thursday.
&&
.AVIATION...
Issued at 613 PM CDT Fri May 29 2020
The TAFs are VFR. The cold front has cleared all terminals.
Lingering scattered high clouds will diminish as high pressure
builds over the area. Winds will be generally light and variable
overnight, becoming northwesterly after daybreak at 4-7 kts.
Could see some scattered high cloud arriving tomorrow afternoon as
a weak impulse passes north of the region.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DWS
SHORT TERM...Smith
LONG TERM...ATL
AVIATION...DWS
Area Forecast Discussion
National Weather Service Reno NV
157 PM PDT Fri May 29 2020
.SYNOPSIS...
Strong high pressure continues to bring very warm to hot
temperatures for the remainder of today. Chances for showers and
thunderstorms in eastern California and western Nevada develop later
this afternoon and increase early Saturday as low pressure moves
into northern California. Windy and much cooler conditions are
expected for Saturday with average temperatures and chances for
showers continuing into next week.
&&
.SHORT TERM...
Very little changes were made to the short term forecast this
afternoon. For the most part, everything looks to be on track. Hot
temperatures and isolated thunderstorms for the rest of this
afternoon/evening and then more thunderstorm activity early Saturday
with strong winds and cooler temperatures thanks to the presence of
a low pressure system moving into northern California.
On the drive into the office this morning, some altocumulus clouds
were visible suggesting the mid to upper-levels were beginning to
moisten up. As the morning progressed, thunderstorm activity for
this afternoon was questioned due to cloud cover continuing to
increase possibly reducing overall heating which could inhibit
thunderstorm development. But, taking a look at the current visible
satellite imagery over the region, there is a back edge to these
mid to upper-level cloud decks along the western slopes of the
Sierra. Therefore, some breaks in this cloud cover should take
place within the next hour or so. Not much on radar yet, but short
term models are showing convection to begin in the next few hours
along the eastern Sierra and into the Tahoe Basin. A few cells
are also possible to form around the Reno-Sparks and Carson City-
Minden areas during this time.
Here are the details regarding temperatures, showers and
thunderstorms, and winds for the rest of today into Saturday:
* TEMPERATURES: With the ridge axis over the Four Corners region,
very warm temperatures for eastern California and western Nevada
are currently being felt with highs expected to be in the low to
mid 80s for Sierra valleys and mid to upper 90s for western Great
Basin valleys. The incoming upper low for Saturday will cause a
huge temperature swing as compared to today`s with highs 20-25
degrees colder. Highs rebound to near average on Sunday with mid
60s to lower 70s in Sierra valleys and mid 70s to lower 80s for
Basin valleys.
* SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON-EVENING: Later this
afternoon into the evening, cumulus buildups in the Sierra south
of I-80 and out into far western Nevada are expected to develop
into isolated-scattered showers with a few thunderstorms. Since
the best forcing with the aforementioned upper low arrives late
tonight and Saturday morning, convection later today will still be
largely dependent on instability from daytime heating and
convergence from zephyr flow off the Sierra.
Still, with rather classic inverted-V soundings and at least a few
hundred J/KG of CAPE likely (HREF progs, NAM/GFS soundings) near
the Sierra, thunderstorms could bring an enhanced threat for
outflow gusts up to 40-50 mph in addition to the standard brief
light-moderate rain and chance for cloud-to-ground lightning
strikes.
* RAIN WITH EMBEDDED THUNDERSTORMS LATE TONIGHT-SATURDAY: Forcing
with the negative-tilt upper low and an associated 100+knot jet
arrives in earnest by around daybreak Saturday for northern and
northeastern CA. This is expected to result in a blossoming of
showers and a few embedded thunderstorms in northeast CA Saturday
morning with a good chance at wetting rains from about I-80
northward. Meanwhile, western and northwestern NV will be on the
periphery of the best forcing so precipitation may be more of a
quick shot with considerably lower totals than farther west.
However, some mesoscale simulations from the HRRR continue to show
the possibility for thunderstorms (low confidence) in far western
NV Saturday morning which could amp up local rainfall totals quite
a bit. Even farther east into west- central NV, conditions look
mainly dry with wind being the main impact on Saturday.
* WINDS TODAY AND SATURDAY: Most areas will continue to see
unremarkable breezes today (outside of any thunderstorm outflows);
however, the Chalfant Valley in southeast Mono County and areas
east of Hwy 95 and south of Hwy 50 in the Basin look to see
considerably higher winds per MOS guidance and short-range model
guidance... with gusts 30-40 mph possible. For Saturday, we have
issued a Wind Advisory for Pershing, Churchill, and Mineral
counties along with Lake Wind Advisories for area lakes, including
Tahoe. Winds will pick up area-wide with widespread sustained
winds 15-25 mph with gusts 30-45 mph. Some guidance even shows the
possibility for winds 20-35 mph with gusts to around 50 mph east
of Highway 95 out in the Basin and Range. These winds would be
quite likely, if they develop, to pick up dust and spread it
northward across Hwy 50 and I-80 near/east of Hwy 95 Saturday
afternoon and evening.
-LaGuardia/Snyder
.LONG TERM...Next week...
As we begin the month of June (how crazy is that?), forecaster
confidence is increasing in a broad troughiness pattern setting up
for most of the west coast through next week. This translates to
around average low and high temperatures, breezy afternoon winds,
with chances for isolated to scattered rain showers and
afternoon/evening thunderstorms. No signals for any significant
storms or high pressure ridges forming over the region for next week.
-LaGuardia
&&
.AVIATION...
Expect isolated thunderstorms later this afternoon in the Sierra
with a 20-30% chance for a storm in the vicinity at KMMH, KTVL, and
KTRK. There will also be slight chances for thunderstorms for
portions of western Nevada and northeast California later this
afternoon, possibly impacting KRNO, KCXP, and KMEV. Showers and
thunderstorms are forecast to continue overnight into early Saturday
morning for the Tahoe Basin, northeast California, and portions of
western Nevada although there will be a lull for a time between
later this evening and early Saturday morning ahead of lifting from
an incoming upper low. Expect IFR/MVFR conditions at times and
possible strong outflow gusts, small hail, brief downpours, and
lightning are near any thunderstorms.
Winds become gusty this afternoon across Mineral County and far
southern Mono county with gusts up to 35 kts. Southwest winds on
Saturday are expected to be moderately strong across most of the
Sierra and western NV with gusts in the 25-40 kt range. Moderate
turbulence, especially if traveling over the Sierra, is anticipated
for much of Saturday afternoon. Winds look to ease by midnight
Sunday. JCM/LaGuardia
&&
.FIRE WEATHER...
Red Flag Warning across the eastern Sierra and western NV starts at
8 AM Saturday. No big change in the forecast reasoning with low
pressure moving through California tonight and Saturday. Winds
should increase rather quickly Saturday morning, perhaps sooner than
the official start time of the Red Flag Warning.
Thunderstorms this afternoon and this evening should remain confined
to the Sierra Front and west of Yerington to Pyramid Lake, including
the Tahoe Basin and Plumas NF. Storms should move quick enough to
limit rainfall raising the treat for a few lightning ignitions.
Gusty outflows are also possible if any stronger storms develop.
Showers and a few thunderstorms should re-fire after 3 am Saturday
when the low reaches the Sac Valley. Some decent potential for
wetting rains from Tahoe northward to Lassen Saturday morning.
* Red Flag Warning Details...
Southern Mono County...Breezy south to southwest winds (gusts near
30 mph) and low humidity today, may not let up much tonight as low
pressure approaches. Thunderstorm chances this far south look to be
only 5-10%. Winds will shift toward the southwest and west Saturday
with an uptick in humidity, peak gusts could reach 40-45 mph. Some
concern the stronger gusts may kick rather early tonight after 2am
or so.
The Sierra Front...A few thunderstorms this afternoon and again
Saturday morning followed by southwest to west winds with gusts 30-
45 mph the main concern. Humidity may rise above 30% during the day
Saturday with much cooler temperatures. Recent warm/dry weather,
threat for a few lightning ignitions, and strong winds are enough to
have a heightened awareness Saturday.
Pershing, Churchill and Mineral Counties...South winds will kick in
Saturday morning with 30-50 mph gusts and humidity below 20%.
Winds should decrease by Saturday evening along with rising
humidity. Brong
&&
.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 8 AM to 8 PM PDT Saturday NVZ423-429.
Wind Advisory from 8 AM to 8 PM PDT Saturday NVZ001-004.
Red Flag Warning from 8 AM to 8 PM PDT Saturday NVZ420.
Red Flag Warning from 8 AM to 8 PM PDT Saturday below 7000 feet
in NVZ421.
Lake Wind Advisory from 8 AM to 8 PM PDT Saturday NVZ002.
Lake Wind Advisory from 8 AM to 8 PM PDT Saturday for Washoe
Lake in NVZ003.
CA...Red Flag Warning from 8 AM to 8 PM PDT Saturday below 7000 feet
in CAZ274.
Lake Wind Advisory from 8 AM to 8 PM PDT Saturday CAZ073.
Lake Wind Advisory from 8 AM to 8 PM PDT Saturday CAZ072.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
757 PM EDT Fri May 29 2020
.UPDATE...
Upper trough lifting from the Great Lakes with weaker and warmer
SW flow aloft this afternoon as enhanced upper energy has moved NE
of the area. Diurnal convection mainly seabreeze driven not as
organized or strong as yesterday. This convection to continue to
wane and drift mainly inland on numerous outflow boundaries.
Overnight, continue to expect clearing skies with temps slightly
warmer than seasonal averages. Will adjust grids and forecasts
based on radar trends otherwise is fair shape.
&&
.AVIATION...
VCTS waning this evening with VFR conditions and light winds
tonight. Another round of VCTS Saturday afternoon.
&&
.Prev Discussion... /issued 200 PM EDT Fri May 29 2020/
SYNOPSIS...
Strong stacked ridging continues to reside over the Western
Atlantic. Meanwhile, a highly amplified pattern over the US with
ridging out West and troughing over the eastern half of the CONUS.
Associated surface cold fronts slowly work their way southeast
over the upcoming weekend. Finally, the tropical wave to the east-
southwest Bermuda, which has the potential of subtropical
development, will quickly get pulled off to the north and away
from the CONUS in the coming days as it becomes sandwiched between
a digging trough in the northwest Atlantic and a large omega
block over the north/central Atlantic.
DISCUSSION...
Today, surface ridging has built slightly and move north,
bringing more of a southerly/southeasterly flow to our area
compared to yesterday. This will favor rain chances a little bit
farther west towards the I-75 corridor along an area of enhanced
convergence formed near the west coast sea breeze. 12Z sounding
out of KTBW shows 500mb temps have warmed approximately 1.5
degrees so the threat of hail will be slightly less. However,
forecast PWAT and MLCAPE are still impressively high for late May
with ~2 inches, and 2500-3000 J/kg, respectively. Furthermore,
afternoon forecast RAP soundings for TBW show wind <10 knots from
the surface to 250mb. This suggests storm motion solely driven by
sea breeze and outflow boundaries. With much of the area
receiving 1-2 with localized 3-4 inches of rain yesterday (and a
lot of rain the previous day as well for some spots) , the
threshold for minor urban and small stream flooding will be lower.
So this will be something to watch for.
Low dewpoint depressions and calm winds will promote some patchy
fog north of I-4 and inland tomorrow morning. Meanwhile, the ridge
will axis will be located across the Suncoast, 1000mb-700mb flow
becomes light and variable in this location so initial storm
development will be favored across the spine of the peninsula in
Central FL. However, weak/moderate southwest flow across the
Nature Coast will promote a few earlier showers/storms in this
area. Later tomorrow, a weak upper level trough stretched across
the panhandle through the carolinas will push eastward. At the
surface, an associated weak frontal boundary will sag south into
the Big Bend of FL by Sunday morning. Westerly low-level flow will
usher in relatively drier air which will limit rain and
thunderstorm coverage some, especially for our western counties.
This front will be very weak and nearly stalled out across our
area on Sunday before very broad surface high pressure builds
across the eastern half of the CONUS. This reinforcing high
pressure will push it south-southwestward as a backdoor front.
This will bring breezy easterly winds to the area by Monday Night
or Tuesday and much drier air with less oppressive humidity,
especially along and north of I-4 corridor. Rain chances will
still be possible in the region of higher PWAT (South Central and
Southwest FL) through mid-week. The enhanced easterly flow will
also promote more showers/storms over the Gulf waters just about
anytime of day. Models diverge by Friday but it does appear
moisture will begin to get advected back northward as the western
flank of the ridge axis begins to degrade.
MARINE...
Surface high pressure will continue to across the Gulf waters
keeping mostly light winds and calm seas through the weekend.
However, isolated to scattered showers and thunderstorms each day
will be capable of producing frequent lightning, locally gusty
winds, and rough seas. Early next week a breezy east to northeast
flow will setup with winds speeds approaching exercise caution
criteria.
FIRE WEATHER...
Ample moisture will preclude any major fire weather concerns
through the weekend with overall weak winds. Daily afternoon
showers and thunderstorms will be capable of frequent lightning
and gusty winds from outflow boundaries. Some patchy fog will be
possible late overnight into Saturday morning for Pasco county
northward.
&&
.Preliminary Point Temps/PoPs...
TPA 74 89 75 89 / 20 40 10 20
FMY 74 89 74 89 / 50 60 10 30
GIF 72 89 72 89 / 40 80 10 50
SRQ 73 89 75 89 / 10 30 10 10
BKV 70 89 71 90 / 20 50 10 20
SPG 75 89 75 89 / 10 40 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
Davis